Low loss dielectric materials for LTCC applications: a review

Low loss dielectric materials for LTCCapplications: a review

M. T. Sebastian1 and H. Jantunen*2

Small, light weight and multifunctional electronic components are attracting much attention

because of the rapid growth of the wireless communication systems and microwave products in

the consumer electronic market. The component manufacturers are thus forced to search for new

advanced integration, packaging and interconnection technologies. One solution is the low

temperature cofired ceramic (LTCC) technology enabling fabrication of three-dimensional

ceramic modules with low dielectric loss and embedded silver electrodes. During the past

15 years, a large number of new dielectric LTCCs for high frequency applications have been

developed. About 1000 papers were published and y500 patents were filed in the area of LTCC

and related technologies. However, the data of these several very useful materials are scattered.

The main purpose of this review is to bring the data and science of these materials together, which

will be of immense help to researchers and technologists all over the world. The commercially

available LTCCs, low loss glass phases and researched novel materials are listed with properties

and references. Additionally, their high frequency and thermal performances are compared with

the other substrate material options such as high sintering temperature ceramics and polymers,

and further improvements in materials’ development required are discussed.

Keywords: LTCC, Dielectric, Shrinkage, Glass, Permittivity, Q value, Temperature compensation, Constraint sintering

IntroductionThe microwave devices have been traditionallymachined from metal, and coaxial RF connections areprovided with connectors generally leading to expensiveheavy and bulky packages.1,2 These metal packagescannot meet the market demand for portable and lowcost modules with multiple external I/Os. Additionally,electronic circuits for the automotive industry, enter-tainment electronics and telecommunications have tohandle today a steady increasing amount of functionsoccupying as tiny space as possible. In the developmentof complex miniaturised circuits, flexible glass ceramictapes, so called low temperature cofired ceramic (LTCC)tapes, play a decisive role as a base material. The LTCCshave been used for the past 15 years or so, and havebecome crucial in the development of various modulesand substrates.3–5 This technology combines many thinlayers of ceramic and conductors resulting in multilayerLTCC modules and have been generally used in theform of a three-dimensional (3D) wiring circuit boardtoday, using low permittivity (usually er<4–9) dielectric

compositions. Additionally, it enables in a versatile mixof passive microwave components such as microstrips,strip lines, antennas, filters, resonators, capacitors,inductors, phase shifters and dividers making possiblea whole matrix of design that are not practical onregular alumina or any soft substrates. Furthermore,these integrated components are interconnected with3D strip line circuitry.3,6,7 Among the various com-ponents which could be realised in LTCC packages,the resonators and internal capacitors are importantin terms of the latest technology. The internal capa-citors are required to realise decoupling capacitorsmonolithically in LTCC packages, and the resonatorsare needed for filters of quarter wavelengths on theLTCC layer. The appropriate relative permittivityrange for the resonators and the internal capacitorsis 20–100 or even more.8,9 The embedding of these pas-sive elements into a module also decreases its foot-step saving top surface for discrete active componentsassemblies.

The low sintering temperature provided by the LTCCtechnology is the key issue enabling its advantageousutilisation for today’s packaging concepts in microelec-tronic and microsystems and in microwave modules.Since the LTCC tapes can be sintered at low tempera-tures (,950uC), the embedded microwave componentsand transmission lines can be fabricated using highlyconductive and inexpensive metals such as silver orcopper with low conductor loss and low electricalresistance at high frequencies. This is an advantage over

1Materials and Minerals Division, National Institute for InterdisciplinaryScience and Technology, Trivandrum 695019, India2Microelectronics and Materials Physics Laboratories and EMPARTResearch Group of Infotech Oulu, University of Oulu, PO BOX 4500,FIN-90014 Oulu, Finland

*Corresponding author, email [email protected]

� 2008 Institute of Materials, Minerals and Mining and ASM InternationalPublished by Maney for the Institute and ASM InternationalDOI 10.1179/174328008X277524 International Materials Reviews 2008 VOL 53 NO 2 57

other ceramic technologies. Furthermore, throughmaterials’ research novel LTCCs with low dielectricloss, tan d (or high Q), and temperature compensatedrelative permittivity have been developed. If low thermalexpansion (close to that of silicon), high strength andhigh thermal conductivity of the LTCCs are also takeninto account, this technology can be seen very desirableeven against polymer materials especially for low loss,high frequency circuits required for high speed datacommunications.

The main purpose of this paper is to gather togetherthe research carried out, discuss the performancesavailable with different materials’ combinations andguideline further development required. A comparisonof the material properties of a range of LTCC tapesystems and some well known commercially availableRF and microwave substrate and printed circuit board(PCB) materials are given in Table 1. For applicationalreasons, low permittivity materials enabling fabricationof devices for high speed applications, are especiallydiscussed. Additionally, the high relative permittivity,low dielectric loss and temperature stability of theelectrical properties enabling microwave filters, withconvenient size and impedance matching, low insertionloss, steep cutoff of the performance curve and opera-tional stability against ambient change,10 are presented.The number of papers published and patents filedincreased exponentially as shown in Fig. 1.

LTCC process and design aspects ofmicrowave componentsIn the LTCC fabrication process, a slurry being amixture of ceramic powder and glass and/or sinteringaids in binders and organic solvents, is cast under‘doctor blades’ to obtain a certain tape thickness. Theholes or vias to the dried tape are mechanically punchedor laser aided micromachined followed by filling with aconductive paste. A stencil and screen printing processesare used to generate conductive patterns. Ceramic sheetsare then stacked, laminated and sintered followed bypost-firing metallisation, electrical testing and finalassembly. Table 2 shows the basic design rules commonfor LTCC modules as well as some process variation tobe taken into account. A more detailed description ofthe process is described elsewhere.11,12 The individualprocess to process variations are large, and dense, fineline technique and positioning accuracy of differentLTCC layers are important. This is especially importantas the operational frequency increases, since more viasare needed to provide isolation between differentelements as the dimensions of discrete elements decreaseat higher frequencies. Several methods especially suita-ble for LTCC tapes enabling line widths ,100 mm havebeen developed.13,14 The positioning accuracy neededdepends on the size of the discrete structures in themodule. Usually the stacking of different layers is

Table 1 Summary of substrate material properties

Material er tan d Remark

FR-4 y4.0 0.0250 –Rogers RO4003 3.38 0.0027 Ceramic filled PTFERogers RT/duroid 5880 2.2 0.0009 Ceramic filled PTFEArlon AR600 6.0 0.0035 PTFE/woven fibre glass–ceramicArlon AR1000 10.0 0.0035 PTFE/woven fibre glass–ceramic99.6% alumina 9.9 0.0004 ceramicDupont 951 7.85 0.0063 Glass–ceramicDupont 943 7.5 0.0020 Glass–ceramicFerro A6 5.7 0.0012 Glass–ceramicHeraeus CT800 7.68 0.0039 –Emca T880B 7.94 0.0063 –Taconic RF-60 4.1 0.0028 PTFE woven fibre glass–ceramicTaconic CER 10 5.0 0.0035 PTFE woven fibre glass–ceramic

1 Plot of a number of published papers and b number of filed patents on LTCC versus year

Sebastian and Jantunen Low loss dielectric materials for LTCC applications

58 International Materials Reviews 2008 VOL 53 NO 2

carried out mechanically using pins in punched registra-tion holes. The achieved accuracy is y60 mm which isnot enough for high frequency applications. In suchcases, more accurate optical positioning method isused.15 Another important issue is that large conductorareas, such as grounds, are not desirable in LTCCstructures, because they may cause component warpingduring the cofiring process.16 This forces designers to usemeshed ground planes with metallisation coveragebelow 50%, causing excess decrease in the Q factor ofresonators and degraded isolation properties.

Thermally driven curvature developed in LTCC tapesand laminates can introduce property limiting defects into a device which should be also taken into accountwhen modules are designed. This curvature, caused byimproper organic burnout rather than sintering17 or bynon-uniform shrinkage of the tape, could result inundesirable defects including delamination, cracks andcamber in the final products.18–21 Any such deviationfrom the designed dimensions can significantly affectcomponent assembly and complicate successful electro-nic property specification. In order to meet the abovementioned electrical requirements and processingdemands, it is necessary to control the particle size,shape and purity of the raw material powder as well ascomposition of the compound. This control is importantalso since conductor loss is sensitive to surface rough-ness at high frequencies and the surface of conductorsdeposited on a dielectric substrate reproduces the shapeand topography of that substrate.

However, the benefits of the LTCC technology, suchas the parallel manufacturing process with high yieldand low cost, the ability to utilise highly conductive andinexpensive metallisation, quick rounds in prototyping,environmental stability, compact structures, integration,etc., makes the techniques unique.22 Several papers haverecently been published about the excellent performance

of LTCC microwave modules up to 75 GHz.23,24

Although there are also other highly dense multilayersubstrate technologies available, such as organic lami-nates, the LTCC has a unique set of combinedcharacteristics, which makes it a more attractivealternative as the operational frequencies shift into themicrowave region.

In fact, considerable attention is needed in selectingthe LTCC material to meet the demands of LTCCprocess, electrical function of multilayer components,external interconnections, reliability and sealing.

Materials selection and requirementsAlthough the LTCC technology for high frequencyapplications demonstrates some very advantageousfeatures, its development is still in the early stages. Themain problems relate to the rigorous demands placed onthe materials requirement. In general, it is believed thatthe main difficulties in the development of new LTCCmaterials are not only related to their dielectric proper-ties but also to their sintering behaviour, thermomecha-nical properties, chemical compatibility, production costand the range of variation of each parameter. There aretwo limiting factors which prevents us from getting lowtotal loss of designed components. One is related to theconductivity losses in the circuitry and the other to thelosses occurring in the glassy phase of the glass–ceramiccomposite substrate or other dielectric loss factors. TheLTCC materials should also have a good thermalconductivity, good mechanical properties and shouldnot react with the conductive material used. Table 3shows some of the properties of commercial LTCCmaterials from data sheets compared with alumina andFR-4.

Important characteristics of LTCCs

Densification temperatureThe densification or sintering temperature of the LTCCshould be less than 950uC, since the common electrodematerial, Ag, melts at 961uC. To produce a module, theLTCC materials are cofired with an inner electrodestructure and as a consequence, the sintering tempera-ture must be lower than the melting point of theelectrode. In addition, a chemical compatibility betweenthe LTCC material and the electrode must exist. Silverpaste is a usual choice for the electrode, which meansthat the sintering temperature is commonly adjusted toy900uC. Copper, gold or gold palladium are other

Table 3 Properties of commercial LTCC materials, alumina and FR-415

Property Commercial LTCCs Alumina (96%) Coors FR-4

Permittivity commonly at 1 MHz 3.8–9.2 9.2 5.5Loss tangent commonly at 1 MHz 0.0007–0.006 0.003 0.022Microwave insertion loss (at 10 GHz), dB m21 4.7–23.6 – –CTE, ppm K21 4.5–7.5 7.1 12–16Thermal conductivity, W m21 K21 2.0 – 4.5 21 0.2Young’s modulus, GPa 80–150 314 24Flexural strength, MPa 116–320 397 430Surface roughness, mm in.21 ,1–25 ,25 –Green tapes thickness tolerance, % ¡2 to ¡9 – –X,Y shrinkage, % (9.5–15)¡0.3 – –Z shrinkage, % (10.3–25)¡0.5 – –Metallisation Au/Ag – Cu

Table 2 Common design parameters for LTCCmultilayers15

Design parameter Value

Minimum width of conductor lines and spaces, mm 150Tolerances of width of conductor line and space, mm ¡20Layer to layer positioning accuracy after firing, mm 60Minimum diameter of vias after firing, mm 150Minimum spaces for vias, mm 300Typical diameter of thermal vias, mm 200–450Ground plane coverage ratio, % 50No. of layers 10–24


International Materials Reviews 2008 VOL 53 NO 2 59

alternative electrode materials with melting points ofy1080uC. Kingon and Srinivasan25 used deposited leadzirconate titanate thin films directly on copper electrodesfor ferroelectric, dielectric and piezoelectric applications.In the glass–ceramic composites, the main phase is adielectric material having high sintering temperature.However, an addition of a glass phase to the dielectriclowers the sintering temperature to a suitable leveldepending on the amount and type of the glasscomposition. In these composites, the main phase isthe crystalline phase which makes a significant con-tribution to the dielectric properties. The glass phaselowers relative permittivity and increases the dielectricloss. The dissolution of the ceramic particles in theglassy phase has an important influence on the viscosityof the melt during the firing. Sintering occurs throughthe viscous flow mechanism in which liquidation of glasshas a dominant role. Thus the selection of glassmaterials is very important and influences the mechan-ical and dielectric properties of the composites.11 Itshould be noted that any densification or crystallisationof the composite at lower temperatures, such as below800uC, is undesirable as this can prevent the evaporationof the organics and solvents used in conductive pastesand binder and plasticisers causing residual carbontraces in the microstructure.3,26 Any residual carbon thatmay form during binder decomposition if left in theLTCC would adversely affect the dielectric properties asshown in Fig. 2. It is estimated that the residual carboncontent should be below 300 ppm to get the desirabledielectric properties.3 The removal of last traces ofcarbon from the green sheet extends up to 800uC asshown in Fig. 3. This means that the densification of theceramic should starts above this temperature.3 Thuscomplete carbon removal makes the selection of theglass–ceramic and identification of a suitable composi-tion very challenging. This is the reason that, e.g.borosilicate based glass–ceramics are not often usedsince they have a shallow viscosity–temperature relation-ship and they exhibit a softening point of y750uC.These facts also relate, not only glass–ceramic compo-sites but, also to the LTCCs developed using sinteringaids or compositions having intrinsically low sinteringtemperature.

Relative permittivity er

The dielectric properties of a particular LTCC materialdetermine its functionality. Low relative permittivitymaterials with er in the range of 4–12 are used for

substrate layers while high permittivity materials areused as mainly for capacitor layers or resonatingstructures. Signal propagation is one of the mostimportant aspects in electronic packaging. This is adirect function of the relative permittivity. In the case ofceramic packages, the relative permittivity of theceramic over and within the metal lines is deposited orembedded governs the propagation delay td, which isgiven by27

td~l(er)1=2=c

where l is the line length, er is the relative permittivity ofthe substrate and c is the speed of light. Thus substrateswith low relative permittivity are required to increase thespeed of the signal.3 Figure 4 shows the propagationdelay as a function of the relative permittivity of theceramic materials.

The relative permittivities of commercial LTCCs,which are usually measured at low frequencies, are inthe range 3–10 (Table 1). Alumina and FR-4 also fallinto this range. However, one advantage is that therelative permittivity of all commercial LTCCs is verystable, and batch to batch variations are generally lessthan 2%. Furthermore, the frequency dependence ofthe relative permittivity is commonly very low. Forexample, er of Dupont 943 changes from 7?6 at GHz to7?48 at 12 GHz being y1?6%,28 where as the relative

2 Variation of relative permittivity as function of residual

carbon in glass–ceramic3

3 Polymer degradation in neutral atmosphere3

4 Propagation delay as function of relative permittivity

with different ceramic materials3



permittivity of FR-4 changes, more than 10% in thefrequency range from 1 kHz to 1 GHz.29

One important advantage of the LTCC technology isalso that it can provide compositions with much higherpermittivity (er.20) enabling small embedded capaci-tors, inductors, filters and antennas.30,31 In this case, onemust, however, pay more attention to the componentfabrication, since smaller dimensions mean higherprocessing accuracy especially in the alignment ofdifferent layers. Also to enable 50 V lines in highpermittivity substrate, narrower conductor lines andtheir spaces than possible with the commonly usedscreen printing process are needed.

Qf .1000 GHzRecent material development has produced new genera-tion LTCC systems, e.g. Dupont 943, with low insertionloss values easily satisfying the normal electricalspecifications of high frequency applications.32–34 Asshown in Table 3, the dielectric loss values (loss tangent)of the commercial LTCCs even at low frequencies arecompetitive with the loss values of alumina and muchlower than the values typical for FR-4. At highfrequencies, the situation is even more favourable tothe LTCCs. Actually in the case of the LTCCcomponents, the main losses in the frequency range 4–44 GHz are conductor losses although their role alsoincrease with increasing frequency. The dielectric lossvalue of common LTCC materials, as expressed with theQ value (1/tan d) multiplied by the measurementfrequency in GHz, can easily exceed the value1000 GHz.

tf close to 0The temperature variation of the electrical properties isvery important for practical application and not muchattention has been paid on LTCC materials. Thecoefficient of temperature variation of the resonantfrequency tf) value of 10 ppm K21 causes a 0?11% shiftof the resonant frequency (5?7 MHz at 5?2 GHz) withinthe temperature range from 230 to z80uC, a commonoperation temperature range for mobile terminals. Largetf values are especially problematic, because temperaturecompensation requires additional mechanical structuresor electrical circuits.35,36 Novel LTCC materials withzero temperature dependence of relative permittivityte are now available,30,37 e.g. Heraues CT2000 withte,10 ppm K21. In spite of this, the design engineershould be aware of the fact that the device structure mayaffect its temperature stability. The tf is actually relatedto te and the coefficient of thermal expansion (CTE) bythe relationship

tf~te{al=2

where al is the CTE. However, it should be noted thatthe tf values of the most novel LTCCs are much betterthan those for FR-4 (z80 ppm K21).

Thermal propertiesThe thermal conductivity of LTCC is another importantaspect. The removal of heat generated by the deviceduring operation is critical for the efficient and reliablefunctioning of the package. This is especially true if heatsensitive discrete components are assembled on a LTCCmodule. Maintaining the temperature of these devicesbelow 100uC is commonly desired. Hence the heat

removal is a very important function of the package.The heat removal has become even more critical inrecent years because of the ever growing need tofabricate high density and high power devices that canoperate at high speed. Considerable attention shouldalso need to be paid to the thermal design as higherpackaging density and operating frequencies increasepower density. One disadvantage of LTCC is its lowthermal conductivity usually in the order of 2–5 W m21 K21, although it is 10 times more than thatfor organic laminates. In high power applications, suchas microwave amplifier packages, the low thermalconductivity of LTCCs may drastically increase relia-bility problems. A common method to improve thermaldissipation is to use a heat spreader, but a moreadvantageous alternative provided by the LTCC tech-nology is to place metallic via arrays under high powercomponents.38

Another important material aspect is its CTE. Forexample, in the systems based on silicon chips with ahigh device density mounted on LTCC substrates, athermal expansion mismatch would give rise to failure ofsolder connections between the chip and the substrate.These affect the reliability of the designed components.The CTE should thus be chosen such that it matches thevalue of the mounting board and chip. This means thatif the LTCC module is mounted on silicon, CTE shouldbe y4 ppm K21 while on alumina, it should be 7–9 ppm K21 and on PCB, 12–20 ppm K21.3,26 Thematch of the thermal expansion of the LTCC withother materials can be performed in some limits with theadjustment of the phases present in its microstructure.The materials having a large amount of glassy phasescommonly show low thermal expansion.

Chemical compatibility with electrode materialFinally, the LTCC should not react with the electrodematerial. The formation of additional phases in theceramic should thus be minimised since their reactionswith the conducting electrode can degrade the perfor-mance of the microwave modules. A critical issue inmanufacturing LTCC microelectronics is the precise andreproductive control of shrinkage of the whole moduleon sintering. Antonio et al.39 successfully applied mastersintering curve theory as a tool to predict and controlthe LTCC sintering. The system itself is, however,complicated since the conductive patterns are printedusing pastes, instead of pure metals, containing con-ductive particles in glassy or frit less additives. Thus,when developing LTCC materials, one has to take intoaccount reactions not only with the conductive materiallike silver, but also with other additives of the conductorpaste.

Commercial LTCC materialsTable 4 gives a list of almost 60 commercially availableLTCCs and their properties. A great majority of thesematerials have relative permittivity lower than 10 andonly six of them reach higher values with the highest of25. The lowest loss tangent values within thesecommercial LTCCs at 2 GHz are near 0?0002 (Qf:,10 000 GHz). However, for a designer or a researcher,it is difficult to make solid comparisons. One reason isthat measurements are carried out at different frequen-cies. Especially since the dielectric loss depends on



frequency, one has to do accurate premeasurements atdesired frequency before selecting the material for aproduct or before comparing the compositions. Anotherproblem especially in mobile phone use is that the tf

value is not commonly given. Thus standardisation ofthe measurement frequencies could provide moreadvantages and productive utilisation of the LTCCtechnology. It should be noted that the Table 4 does notinclude materials which are used internally by several

manufacturers. The lack of this information hinders thefull commercial utilisation of the LTCC technology.

Glass–ceramic compositesMost conventional electroceramics do not meet the basicrequirements with regard to sinterability for LTCCtechnology since they have relatively high sinteringtemperature. In general, there are several methods to

Table 4 Dielectric properties of commercial LTCCs

LTCC supplier Composition er Q or tan d (f)

Asahi glass 35 wt-%Al2O3z25 wt-% forsteritez40 wt-%BSG glass 7.4Kyocera G 55 G 55 (BSGzSiO2zAl2O3zcordierite) 5. 800 (10 GHz)Kyocera GL 660 9.5 300 (10 GHz)Kyocera JHB62 (Pb–borosilicate glasszAl2O3zSiO2) 7.9 0.0002 (2 GHz)Kyocera JIB62 18.7 0.00025 (2 GHz)Kyocera AAB62 9.4 0.0005 (3.2 GHz)Kyocera GL 560 6 0.0017Kyocera GL 530 4.9 0.0006 (2 GHz)Murata BAS (Celsian) (BaO–Al2O3–SiO2) 6.1 300 (5 GHZ)Murata CaZrO3zglass 25 700 (5 GHz)Murata BaO–B2O3–Al2O3–CaO–SiO2 6.1 0.0007NEC glass MLS-25M (Al2O3–B2O3–SiO2) 4.7 300 (2.4 GHz)NEC MLS-41 (Nd2O3–TiO2–SiO2) 19 500 (2.4 GHz)NEC MLS-1000 (PbO–Al2O3–SiO2) 8 500 (2.4 GHz)NEC MLS-61 8.1 150 (2.4 GHz)NEC vacuum glass GCS78 (PbO–BSG glasszAl2O3) 7.8 .300 (1 MHz)NEC vacuum glass GCS 71 7.1 .300 (1 MHz)NEC vacuum glass GCS 60 6.0 .300 (1 MHz)Sumitomo metal LFC (CaO–Al2O3–SiO2–B2O3zAl2O3) 7.7 –NTK GC-11 7.9 200 (3 GHz)NTK NOC-F1 6.3 0.0028 (40 GHz)NTK GC-21 7.6 0.003 (3 GHz)Matsushita MKE-100 (PbO–glasszAl2O3) 7.8 500 (1 MHz)Niko NL-Ag II 7.8 .300 (1 MHz)Niko NL-Ag III 7.1 .300 (1 MHz)Maruwa HA-995 9.7 –Dupont 951 (Al2O3zCaZrO3zglass) 7.8 300 (3 GHz)Dupont 943 7.8 500 (40 GHz)Ferro A6M 5.9 500 (3 GHz)Ferro A6-B 6.5 0.005Electro-Science Lab 41020-70C 7–8 200 (1 MHz)Electro-Science Lab 41110 4.2 0.0037 (3 GHz)Heraeus CT700 7.5–7.9 450 (1 MHz)Heraeus CT2000 9.1 1000 (450 MHz)EPCOS K8 7.8 0.001EMCA T8800 7.2 0.002Motorola T2000 9.1 0.003Amkor GCS 50 5.0 0.001 (10 GHz)Amkor GCS 71 7.1 0.005 (10 GHz)Amkor GCS 60 6.0 0.001 (10 GHz)Amkor GCS 44 4.4 0.001 (10 GHz)Amkor GCS 2000 18.0 0.006 (10 GHz)Samsung TCL-6A 6.3Samsung TCL-70 6.8Taiyoyudan Al2O3–CaO–SiO2–ZrO2–MgO–B2O3 6.7 0.001Taiyoyudan Al2O3–SiO2–ZrO2–MgO 7.3 0.002Tektronix MgO–CaO–silicatezAl2O3 5.8 0.0016Toshiba BaSnB2O6 8.5Toshiba BaO–SnO2–TiO2–B2O3 7–13 0.0005–0.0008Noritake Al2O3–forsteritezglass 7.4Shoei BaZr(BO3)2 7.0 0.001Alcoa Borosilicate glasszSiO2zdopants 3.9–4.2 ,0.003NGK ZnO–MgO–Al2O3–SiO2 (cordierite) 5.0IBM Cordierite crystallised glass 5.0Corning Crystallisable glasszcrystalline cordierite 5.2Hitachi (BaO–Al2O3–BSG)zAl2O3zZrSiO4 7.0Hitachi Pb–aluminoborosilicatezAl2O3, CaZrO3 9.0–12 0.001–0.003Fujitsu Al2O3–BSG (50 : 50 wt-%) 7.8Fujitsu Borate glasszAl2O3,SiO2 4.9



lower the sintering temperature of ceramics, such as useof a glass with low melting temperature, addition ofoxides as sintering aids, chemical processing and usingstarting materials with small particle size. In this paper,the sintering aid method is discussed with actualexperiments later on and the chemical processingmethod or the use of small particles are ignored asthese are less commonly used methods. The use ofglasses, however, is explained here in more detail since itis found to be an effective way to decrease the firingtemperature and also being the most commonly usedmethod. Table 5 lists most commonly used glasses in theLTCCs with physical properties. In practice, there aretwo approaches to exploit glasses to obtain ceramiccompositions sinterable below 1000uC.

The first approach is via the glass–ceramic route,which starts with a fully glassy system that devitrifiesalmost completely during the sintering process. Thedevitrification of glass greatly increases the viscosity ofthe system during firing, thereby improving the resis-tance to distortion.40 The starting materials used in theapproach are pure glasses, such as cordierite glass,40

which densifies first, followed by crystallisation. Thephysical properties of the resulting composition arecontrolled by the degree of crystallisation, which can beenhanced by the addition of a small amount ofcrystalline phase which acts as a nucleating agent.During the sintering, the glass recrystallises to low lossphases and produces a low dielectric loss ceramicbody.41 Thus during the heat treatment, when the glassis transformed into a glass–ceramic material, not onlycomplete densification should be obtained, but alsosufficient crystallisation must be achieved. Otherwise,high porosity or low degree of crystallinity can result inrelatively poor mechanical properties. Another consid-eration is that an addition of some sintering aid ornucleating agent would also show42 difference inproperties, such as the relative permittivity er, qualityfactor Q, the CTE and temperature coefficient of therelative permittivity te. As a result in this approach,optimisation of glass–ceramic composition and furtherunderstanding of the related property differences withcrystallinity is vital. A good example is Ferro A6Mcontaining CaO–SiO2–B2O3 glass. During firing, thecrystallites of wollastonite (CaSiO3) are formed, andsome residual borosilicate glass is also present in thesintered product. This type of dielectric tape is suitablefor 20–30 GHz applications such as in military andaerospace applications where very low losses arerequired.

In the second approach (glasszceramic), the startingmaterial consists of a low softening point glass anda crystalline ceramic.3,40,43,44 The densification ofglasszceramic has been described by a three stageliquid phase sintering by particle rearrangement, dis-solution and precipitation and solid state sintering.45–54

Depending on the type and amount of glass added, twosintering mechanisms are possible:55,56 reactive and non-reactive liquid phase sintering. The densification ofglasszceramic can be further classified as non-reactive,partially reactive and completely reactive system,depending on the reactivity between glass and ceramics.Little dissolution of ceramic filler in glass during thesintering is observed for non-reactive systems, such asborosilicate glass (BSG)zcordierite, in which the

densification is mainly achieved by particle rearrange-ment.50,57 The required amounts of glass content toachieve densification decrease with increasing theparticle size ratio between ceramic filler and glass.51 Insome cases with a mixture of low melting glass andceramic filler, the role of the glass is not only to serve asa bonding agent to hold the ceramic particles but is alsoto react with filler ceramic at the sintering temperatureto form high Q crystalline phases. In this type of reactivesystem, the microstructure, phases and final propertiesare controlled by the sintering conditions, such asheating rate, sintering temperature and soaking time.For partially reactive systems such as BSGzalumina,57

the dissolution of ceramic filler in glass is localised andlimited, and no particle growth and shape accommoda-tion are observed. The required BSG content to achievedensification is close to that of non-reactive system suchas BSGzcordierite.50,51 A lower and slower densifica-tion results when larger BSG or ceramic filler particleis used for a completely reactive system.53 Jean andLin studied the densification kinetics of non-reactive (BSGzcordierite),50,51 partially reactive(BSGzalumina and BSGzTiO2)52,54 and reactive(BSGzhigh silica glass)53 glasszceramic systems. Inthe case of alumina–glass composites, very small amountof alumina dissolve in the glass at the sinteringtemperature. The small amount of alumina is enoughto suppress crystallisation of the glass or in some casespromote crystallisation of the glass, thus playing animportant role in controlling the properties.11 In the caseof BSG when heat treated, cristobalite, which have largethermal expansion, is precipitated. This makes it difficultto control the thermal expansion of this kind of LTCCand may retard the densification process.58,59 However,precipitation of cristobalite can be suppressed and acomposite with a matrix of amorphous glass can beobtained.60 Jean et al.42 reported that addition of a smallamount of Ga2O3 in a mixture of BSG and silicacan completely prevent formation of cristobalite.Additionally, Nishigaki et al. reported that precipitationof anorthite in alumina–CaO–Al2O3–SiO2–B2O3 glassimproved the mechanical strength of the composites.61

The selection of glass materials is very important tothe sintering process, since the liquification of glass takesa dominant role in the viscous flow mechanism amongconstituents. When glasszceramic composites are sin-tered, the liquification of the glass is the key mechanism,where the glass penetrates the 3D mesh structure formedby the ceramic particles, facilitating the wetting of eachceramic particle surface with glass melt. Thus in order toimprove the sintered density of glasszceramic composi-tion, it is necessary to control the softening point of theglass material, as well as its volume and powder particlesize to increase its fluidity.62,63 It may be noted that theceramic has the effect of hindering the flow of the glassand hence use of ceramic with large particle size lowerthe specific surface area, and is beneficial in improvingthe sintered density. Glass fluidity, crystallisation,foaming and reactions are all important in lowtemperature firing. Additionally the glass consists ofdifferent oxides which all have effect on its properties.11

Commercial LTCC tapes are mainly low er glasszcera-mic compositions having typically four or five phasespresent and none of which should react with theelectrode. SiO2 and B2O3 glasses form commonly the



Table 5 Physical properties of common glasses in LTCCs

GlassDensity,g cm23 Ts, uC Tcryst, uC Tg, uC er

tan d at1 MHz, %

Referenceno.

ZnO–B2O3 (50 : 50) 3.65 582 718 74BaO–ZnO–B2O3 (10 : 45 : 45) 3.85 552 622 6.9 0.009 74, 75BaO–ZnO–B2O3 (15 : 42.5 : 42.5) 3.92 544 615 74ZnO–B2O3 (71 : 29) 2.19 567 4.21 0.003 76BaO–ZnO–B2O3 (20 : 40 : 40) 4.03 536 604 74BaO–ZnO–B2O3 (30 : 35 : 35) 4.39 496 568 74BaO–ZnO–B2O3 (40 : 30 : 30) 4.42 480 532 74La2O3–B2O3–ZnO (1 : 2 : 0.5) – 660 750 640 77La2O3–B2O3–ZnO (1 : 3 : 0.5) – 640 750 610 77La2O3–B2O3 (26 : 74) – 700 – 680MgO–B2O3–SiO2 (42 : 45 : 13) 613 71SrO–B2O3–SiO2 (32.85 : 52.09 : 15.05) 583 71BaO–B2O3–SiO2 (42 : 45 : 13) 560 71CaO–B2O3–SiO2 (42 : 45 : 13) 613 71CaO–B2O3–SiO2 (P2O5 doped) 2.51 820 6.51 0.0018 78ZnO–B2O3–SiO2 (Ferro EG2730) 3.9 615 715 –SiO2–B2O3–Al2O3 (Asahi K801) – 640SiO2–BaO–Al2O3 (Asahi K807) – 725SiO2–BaO–Al2O3 (Asahi LS-5) – 553SiO2–B2O3–CaO (Asahi BS-7) – 789SiO2–MgO–Al2O3 (Asahi FF201) – 820B2O3–Li2O (Asahi K801) – 450La2O3–B2O3–TiO2 (20 : 60 : 20) 722 835 79(40–50)Li2O–(32–40)B2O3–(12–30)SiO2 437–524 420–503 6.4–7.7 0.42–0.58 80(25–40)CaO–(20–31)B2O3–(30–40)SiO2 637–684 570–636 8.0–8.5 0.2–0.3 80(55–60)SiO2–(20–22)B2O3–(2–4)Al2O3–(5–15)AE 732–770 642–685 4.8–5.8 0.15–0.22 80(65–72)SiO2–(20–24)B2O3–(0–2)Al2O3–(2–8)AE 735–780 674–722 4.4–4.8 0.12–0.18 80Li2O–B2O3–SiO2 (51.3 : 36.53 : 12.1) 2.38 422 403 7.21 0.004 81Li2O–B2O3–SiO2 (35.4 : 31.66 : 33.2) 2.34 513 488 6.44 0.0036 81Li2O–B2O3–SiO2 (56.92 : 37.59 : 5.49) 2.4 433 410 7.58 0.0045 81Li2O–B2O3–SiO2 (50 : 40.24 : 9.76) 22.4 398 379 8.15 0.0057 81Li2O–B2O3–SiO2–CaO–Al2O3 (28 : 27 : 30 : 5 : 10) 2.36 484 456 8.12 0.0025 81Li2O–B2O3–SiO2–CaO–Al2O3 (25 : 30 : 33 : 5 : 7) 2.42 484 470 8.12 0.0023 81Li2O–SiO2–CaO–Al2O3 (28 : 27 : 27 : 8 : 10) 2.45 470 450 8.31 0.0027 81Li2O–B2O3–SiO2–CaO–Al2O3 (52.45 : 31.06 : 11.99 : 2.25) 2.31 389 373 8.76 0.0042 81Li2O–B2O3–SiO2–CaO–Al2O3 (44.3 : 29.71 : 16.99 : 4 : 5) 2.32 427 409 8.52 0.0037 81Li2O–B2O3–SiO2–CaO–Al2O3 (36.15 : 28.35 : 22 : 6 : 7.5) 2.38 464 444 8.42 0.0036 81(30–50) wt-%CaO–(10–20) wt-%SiO2–(35–45) wt-%B2O3

z0.5 wt-%P2O5z0.5 wt-%ZnO1.74 6.5 0.002 82

BaO–B2O3–SiO2 (30 : 20 : 50) 717 7.28 0.008 75BaO–B2O3–SiO2 (30 : 40 : 30) 677 7.31 0.0057 75BaO–B2O3–SiO2 (30 : 60 : 10) 627 7.31 0.004 75BaO–B2O3–SiO2 (50 : 20 : 30) 595 9.61 0.01 75BaO–B2O3–SiO2 (50 : 30 : 20) 586 9.52 0.01 75BaO–B2O3–SiO2 (50 : 40 : 10) 577 9.15 0.01 75ZnO–B2O3–SiO2 (50 : 30 : 20) 614 7.08 0.0095 75ZnO–B2O3–SiO2 (50 : 40 : 10) 611 6.91 0.0095 75ZnO–B2O3–SiO2 (60 : 20 : 20) 604 7.51 0.009 75ZnO–B2O3–SiO2 (60 : 30 : 10) 581 7.56 0.011 75PbO–B2O3–SiO2 (30 : 60 : 10) 492 9.06 0.011 75PbO–B2O3–SiO2 (40 : 20 : 40) 442 12.11 0.01 75PbO–B2O3–SiO2 (40 : 40 : 20) 449 12.74 0.009 75PbO–B2O3–SiO2 (50 : 40 : 10) 408 13.78 0.012 75PbO–B2O3–SiO2 (60 : 20 : 20) 348 15.32 0.018 75PbO–B2O3–SiO2 (70 : 20 : 10) 312 19.57 0.02 75La2O3–B2O3–ZnO (2 : 4 : 1) 660 750 640 77La2O3–B2O3–ZnO (2 : 6 : 1) 640 750 610 77La2O3–B2O3–TiO2 (20 : 40 : 60) 722 778 12.6 77B2O3–SiO2 (70 : 25, trace amounts of Li2O, K2O and Na2O) 700–750 4.1 41B2O3–La2O3–MgO–TiO2 (60 : 12 : 18 : 10) 847 661 83BaO–ZnO–B2O3–SiO2 575 600 84B2O3–Bi2O3–SiO2–ZnO (27 : 35 : 6 : 32 mol.-%) 430 21 0.01 85La2O3–B2O3–TiO2 (23 : 35 : 42 mol.-%)zZrO–BaO–SrO(,3 mol.-%)

725 16 85

MgO–B2O3–SiO2 (42 : 45 : 13 vol.-%) 2.32 613 6.64 0.00045 71CaO–B2O3–SiO2 (42 : 45 : 13 vol.-%) 2.77 613 7.47 0.00042 71SrO–B2O3–SiO2 (32.85 : 52.09 : 15.05 vol.-%) 2.29 653 7.12 0.00027 71BaO–B2O3–SiO2 (42 : 45 : 13 vol.-%) 2.71 623 7.63 0.00025 71



network structures of glass. The SiO2, for example, has ahigh melting point and high viscosity. Thus when theSiO2 content is large, the glass has a high transitiontemperature, low thermal expansion and better chemicalstability. Thus addition of B2O3 to quartz (SiO2) glasslowers the viscosity. Na2O, PbO, K2O, Li2O, CaO, MgOand BaO are modifier oxides. Na2O lowers the softeningpoint considerably, but it increases the CTE anddegrades the stability. However, the addition of Na2Oand Li2O modifiers increases the ionic conductivity andthe Li2O crystallises readily. Furthermore, Al2O3 canform AlO4 tetrahedrons and can connect to the networkstructure and has effect of controlling crystallisation.

The glass basically only softens and wets the ceramicpowder during sintering, providing a dense hermeticstructure. At the same time, it allows the dielectric toconform to the setter on which it is fired, bringing anextremely flat finished part. The volume fraction of theadded glass determines the sintering characteristics andthe crystalline filler is a major determinant of electricalproperties, also increasing viscosity during sintering andthereby minimising distortion. The crystalline phase alsoincreases the mechanical strength of the final LTCC.Thus the properties of the final glasszceramic arecontrolled by the ratio of glass to ceramic and theindividual properties of the mixtures. Typically, thesintered properties in this system are designed to matchthe CTE of standard alumina ceramics and to have therelative permittivity of 6–9. The approach ofglasszceramic has been widely used, being apparentlysimple and ease in controlling densification behaviour.However, the composition can produce very compli-cated phase formation. Typical systems with thisapproach include the BSGzalumina by Fujitsu64 andthe lead BSGzalumina by Dupont.65 Table 6 presentsthe crystalline phases commonly considered forglasszceramic systems.

Fujitsu and NEC have developed LTCC systemsusing the above mentioned mixed phases’ methodrequiring their reaction during the sintering process.Fujitsu developed two systems: cordierite–BSG andalumina–BSG systems. Cordierite is interesting becauseit has got a low relative permittivity and its CTE is veryclose to that of silicon.66 In the first composition, asagainst to internally nucleating a crystalline ceramicphase within the glass matrix, the glass was admixed intothe crystalline composition to form a glass and ceramicmixture. The glass and cordierite system fabricatedshowed a high CTE of the order of 17 ppm K21

attributing to the formation of cristobalite. However,

the alumina–glass system did not show large differencein thermal expansion since cristobalite were not pro-duced in the composite system. NEC developed a LTCCsystem consisting of alumina and 45 wt-% lead BSG.67

The use of lead based glass increased the relativepermittivity to 7?8 which is more than that of cordieritebased, but less than alumina. The samples sintered at900uC gave a CTE of 4?2 ppm K21 which is close tosilicon. Crystallisation occurs on heat treatment at900uC as a result of the reaction between the glass andthe ceramic particles, resulting in the formation ofcristobalite. The formation of crystalline quartz alsoimproved the mechanical strength.

As a conclusion, although the use of glass or additionof sintering aids are found to be an effective method todevelop LTCC systems, the reduction of the sinteringtemperature of an original dielectric ceramic is usuallyaccompanied by an abrupt degradation of the dielectricproperties due to the formation of secondary phases.Only in a few cases could the sintering temperature bereduced without degradation of the dielectric propertiesdue to the enhancement of the density of ceramicsor elimination of oxygen vacancies.68 The effectivenessof sintering aids depends on several factors, such assintering temperature, viscosity, solubility and glasswettability.69 The main requirement for liquid phasesintering is that the liquid phase should wet the grains ofthe ceramics. Generally, chemical reaction betweensintering aids and ceramics can provide the best wettingcondition.70 However, chemical reaction often results inthe formation of secondary phases. X-ray diffractionstudy of the glass materials heat treated at 800uCshowed71 that MgO–B2O3–SiO2 is the most susceptiblefor crystallisation and BaO–B2O3–SiO2 represents theleast. For further analysis, Kemethmuller et al.72

proposed a method based on Rietveld refinement forX-ray analysis to determine quantitatively the amountof crystalline phases and also the amount of remainingamorphous phase of glass–ceramic composites.Additionally, Eberstein et al.73 developed a softwarefor calculating the permittivity and dielectric lossaccording to the effective medium theory and effectivefield theory.

Finally the instability source in development ofLTCCs, glass fabrication, must also be controlledcarefully. In almost all cases, initial glass preparationis needed, which involves mixing raw materials to yieldthe chosen glass composition, melting the mixturebetween 900 and 1500uC, quenching and pulverisation.This high temperature step involves volatilisation ofconstituents such as Bi2O3, B2O3 and PbO, which canlead to undesirable variations in the final composition.

Microwave dielectric properties ofglassesThe microwave dielectric properties of ceramics withglass additives strongly depended on the densification,microstructure and interactions between glass andceramics. Single components with low melting pointare often used as sintering aids, but they easily formcomplex compound with matrix ceramics degrading thedielectric properties.86 However, complex additives andmulticomponent glasses are much effective to reduce thesintering temperature of ceramics with good microwave

Table 6 Crystalline phases considered for glass–ceramic3

Composition Crystal phase CTE

Li2O–Al2O3–SiO2 Beta eucryptite 210.0Li2O–2SiO2 Lithium disilicide 11.00Li2O–Al2O3–4SiO2 Beta spodumene 0.9Al2O3–TiO2 Aluminium titanate 0.52MgO–2Al2O3–5SiO2 Cordierite 1.0BaO–Al2O3–2SiO2 Celsian 2.7CaO–Al2O3–2SiO2 Anorthite 4.5MgO–SiO2 Clinoenstatite 7.8MgO–TiO2 Magnesium titanate 7.92MgO–SiO2 Forsterite 9.4CaO–SiO2 Wollastonite 9.4SiO2 Quartz 11.2



dielectric properties.87 Generally, low softening tem-perature glass materials were mixed with the ceramicmaterials to reduce the firing temperature. However,network formers contained in the glass materials mayabsorb the microwave power profoundly in highfrequency region, degrading the quality factor for thematerial.88 At least three types of loss for glasses havebeen distinguished:89 resonance type vibration losses atvery high frequency, migration losses caused by themovement of mobile ions (mainly alkali ions) anddeformation losses by defect or deformation of thebasic silicon oxide network. Resonant type vibrationlosses are particularly important in the microwaveregion. Among the glasses, silica glass has the lowesttan d in the microwave region.91,92 The tan d in fusedquartz is less than 0?001 in the frequency range from16102 to 2?561010 Hz.92 Although the loss level isuseful, silica is not an effective flux to lower sinteringtemperature for microwave dielectrics if used alone. Tolower the melting point, the rigid bonds in SiO2 may bebroken by modifiers such as alkali ions, but the use ofalkali ions considerably increases the loss factor.92,93

The tan d of silica based binary glasses such asborosilicate (B2O3–SiO2) is y0?001 at 3 GHz.94 Thetan d of ternary glasses based92,94 on borosilicates suchas low potash lithium borosilicate at 3 GHz is y0?0012,aluminium borosilicate y0?002 at 3 GHz, and sodaborosilicate y0?004 at 3 GHz. Aluminium silicates suchas cordierite (MgO–Al2O3–SiO2) and celsian (BaO–Al2O3–SiO2) also show low loss factors in the microwavefrequency region.94,95 Wu and Huang75 investigated themicrowave dielectric properties of several low meltingZnO–B2O3–SiO2, BaO–B2O3–SiO2 and PbO–B2O3–SiO2

glasses. The zinc and barium based glasses have low er inthe range 7–9?5, whereas the Pb based glasses have er upto 19?5 depending on the composition (Table 5). Theglasses have a negative tf with Qf up to 3400 GHz. ThePb based glasses have a relatively low Qf. Zhu et al.82

reported that CaO–SiO2–B2O3 with 0?5 wt-%P2O5 and0?5 wt-%ZnO sintered at 820uC showed er56?5 andtan d50?002 at 30 MHz. Mandai et al.96–98 reportedthat BaO–CaO–Al2O3–B2O3–SiO2 glass had er56?1 andQf5400 at 10 GHz, BaO–SrO–SiO2–ZrO2 had er512and Qf51000 GHz, and CaO–ZrO–glass had er525 andQf53500 GHz. Wakino reported91 that MgO–Al2O3–B2O3–SiO2–TiO2 has er56?1 and Qf54200 GHz.

Takada et al.77,99 investigated the microwave dielec-tric properties of rare earth borates. LaBO3 showed thehighest quality factor (53 000 GHz) and the highester (12?5), although the sintering temperature wasy1200uC. The er increased with increasing rare earthionic size. It was found that the Qf improved when amixture of amorphous melt and crystalline mixtures ofLa2O3–B2O3 was fired. The best dielectric properties,Qf572 000 GHz and er58 at 13 GHz, with low firingtemperatures of 900uC, were found when the mixingratio of La2O3–2B2O3–0?5ZnO was 20% crystalline meltand 80% amorphous melt. Kagata et al.100 reported thatMgO–Sm2O3–Al2O3 (MgSmAl11O19) and Al2O3–SiO2–B2O3 in equal amount and sintering at 920uC resultedin LTCC with er57?8, Qf510 000 GHz andtf5z6 ppm K21. Chang and Jean101 studied thecrystallisation kinetics and mechanism of low er, lowtemperature, cofireable CaO–B2O3–SiO2 glass ceramicsusing commercially available A6 tapes. The samples

were fully densified during sintering at 850uC. Severalcrystalline phases of calcium silicate (WollastoniteCaSiO3, Ca3Si2O7 and Ca2SiO4) and CaB2O4 formedduring the firing. Crystalline phases of CaSiO3 andCaB2O4 were the stable phases with CaSiO3 as the majorphase and other phases disappeared on firing at highertemperatures. The relative permittivity decreased andthe CTE remains almost constant with increasingcrystalline phase or with increased sintering durationat 850uC. The samples had a relative permittivity er

of y6 and tan d ,0?2% at 1 MHz. Additionally,Kobayashi and Kato102 reported the low temperaturepreparation of anorthite ceramics, and Lo et al.103

reported the effects of crystallisation level in anorthiteon the dielectric properties. They added 5–10 wt-%TiO2

as the nucleating agent for crystallisation. At a constantheating rate of 5uC min21, the anorthite glass crystal-lised at 950uC. The LTCC dielectric had low er of 8 andQf of 22 500 GHz for the samples containing5 wt-%TiO2. Addition of 5 wt-%B2O3 glass increasedthe er to 10?5 and lowered the quality factor. Kim et al.84

studied the effect of addition of different types of fillers(TiO2, ZrO2, Al2O3, MgO and cordierite) to BaO–ZnO–B2O3–SiO2 (BZBS) (10 : 40 : 40 : 10) glass on CTE,optical reflectance and relative permittivity. All thefillers partially dissolved into the glass at 575uC. TheBZBS glass has er of 9?9. Finally, Lim et al.104 studiedthe effect of BaO content on the crystallisation, sinteringbehaviour and properties of BaO–B2O3–SiO2 glass.Since BaO acted as a network modifier, the glasstransition temperature and crystallisation temperaturedecreased as the BaO content increased. Crystallisationoccurred when more than 50 mol.-%BaO was added.

LTCC materials and their propertiesTakada et al.105 reported in 1994 for the first time theeffect of glass additions on the microwave properties ofdielectric ceramics. Since then, several different types oflow melting glasses and sintering aids have been addedto several low loss dielectric ceramics and sintered attemperatures less than 1100uC. Table 7 gives a list ofthese dielectric materials with their properties andreferences. The following sections explain the importantcompositions researched and the microwave propertiesare thus reported. A few sections discuss the LTCCsystems based on well known dielectric ceramics usedwidely in high frequency applications, and a section tosystems based on dielectrics having originally excep-tional properties such as low sintering temperature orhigh Q value or relative permittivity, and the rest of thecompositions developed are only briefly discussed.

AluminaAlumina, although having somewhat low tf

(260 ppm K21) and high sintering temperature(1550uC), is widely used as substrate materials at highfrequencies. Its er and Qf are 10?5 and 680 000respectively, and thus is a good basic material to startdevelopment of low permittivity LTCC.106 Severalauthors investigated107–112 the effect of various glassadditions on the sintering behaviour and microwavedielectric properties of alumina. The best dielectricproperties were reported by Seo et al.109 when Al2O3

filled with different amounts of La2O3–B2O3 glass wassintered at 950uC. The composition had er of 8?4 with Qf



Table 7 LTCC compositions: sintering temperature,1100uC

Sl no. Material

Sinteringtemperature,uC er Qf, GHz f, GHz ef, ppm K21 References

1 Li3AlB2O6 650 4.2 12 460 16.8 2290 2912 CaO–B2O3–SiO2 (29.3 : 9.3 : 61.4 mol.-%) 900 3.9 1800 9.9 2923 CaO–B2O3–SiO2 (19.8 : 30.9 : 49.3 mol.-%) 900 4.1 2000 9.9 2924 CaO–B2O3–SiO2 (10.5 : 22.2 : 67.3 mol.-%) 900 4.1 2600 9.9 2925 Li3AlB2O6 700 4.9 12 609 16.9 2201 2916 Li3AlB2O6 775 5.4 20 448 17.4 2244 2917 40 wt-%Al2O3z60 wt-% SiO2–B2O3–Al2O3 875 5.4 8000 250 808 NaAlSi3O8 1025 5.5 11 200 25 2939 m-cordieritezB2O3–P2O5 860 5.8 3000 255 29510 a-cordieritezB2O3–P2O5 950 5.8 6000 215 29511 K0?9Ba0?1Ga1?1Ge2?9O8 990 5.9 94 100 12 225 29412 Al2O3zMgO–Al2O3–SiO2–GeO2zZnO–B2O3 900 5.92 5594 8.4 29613 MgO–Al2O3–B2O3–SiO2–TiO2 900 6.1 4200 9114 MgO–Al2O3–B2O3–SiO2–TiO2 ,1000 6.1 4200 6 9915 50 wt-%Al2O3z50 wt-% SiO2–B2O3–Al2O3 875 6.2 11 400 235 8016 KGaGe3O8 970 6.2 19 800 12 221 29417 AlSbO4 1100/3 h 6.3 3200 4 17718 45 wt-%Al2O3z55 wt-% SiO2–B2O3–Al2O3 875 6.3 11 500 233 8019 Mg3(VO4)2 950/5 h 6.4 48 800 283 26820 55 wt-%Al2O3z45 wt-% SiO2–B2O3–Al2O3 900 6.4 13 000 258 8021 K0?9Ba0?1Ga1?1Ge2?9O8 1040 6.4 94 700 12 223 29422 K0?4Ba0?6Ga1?6Ge2?4O8 990 6.6 12 680 12 221 29423 MgO–B2O3–SiO2 (42 : 45 : 13) glass 640 6.64 2137 6.88 7124 ZnO–0.6SiO2zBi2O3–Li2CO3 910/2 h 6.65 33 000 11 270 29725 50 wt-% La2O3–B2O3z50 wt-%Al2O3 850 6.7 2800 17.7 10926 ZnO–B2O3 (50 : 50) glass ,800 6.88 1733 16.36 210 7527 K0?67Ba0?33Ga1?33Ge2?67O8 1020 6.9 32 660 12 227 29428 ZnO–B2O3–SiO2 (50 : 40 : 10) glass ,800 6.91 1717 15.8 221 7529 Ba2V2O7 950 7.0 19 000 274 26930 BaGa2Ge2O8 1100 7 106 400 12 225 29431 SrCuP2O7 925/2 h 7.04 101 110 262 27532 SrZnP2O7 950/2 h 7.06 52 781 270 27533 MgMoO4 900 7.07 79 000 246 29834 ZnO–B2O3–SiO2 (50 : 30 : 20) glass ,800 7.08 1677 15.97 243 7535 SrO-B2O3-SiO2 (32.85 : 52.09 : 15.05) glass 580 7.12 3608 6.98 7136 Mg3B2O6 ,900 7.2 9400 16 25637 SrZnP2O7 925/2 h 7.25 71 520 264 27538 BaO–B2O3–SiO2 (30 : 20 : 50) glass ,800 7.28 1837 14.82 262 7539 BaCu(B2O5) 810 7.3 50 000 232 29940 CaO–B2O3–SiO2 (69.7 : 16.2 : 14.1 mol.-%) 900 7.3 2300 9.6 29241 CaO–B2O3–SiO2 (38.3 : 31.5 : 30.2 mol.-%) 900 7.3 1800 9.6 29242 BaO–B2O3–SiO2 (30 : 40 : 30) glass ,800 7.31 2701 15.35 234 7543 BaO–B2O3–SiO2 (30 : 60 : 10) glass ,800 7.31 3388 14.9 225 7544 CaCuP2O7 900/2 h 7.33 71 620 276 27545 MgAl2O4–Li–Mg–Zn–B–Si–O glass 1000 7.4 48 000 24 290 255, 25646 CaO–B2O3–SiO2 (42 : 45 : 13) glass 600 7.47 2380 6.24 7147 DyBO3, HoBO3 and YBO3 ,800 .7.5 .10 000 9948 ZnO–B2O3–SiO2 (60 : 20 : 20) glass ,800 7.51 1412 15.35 284 7549 ZnO–B2O3 (60 : 40) glass ,800 7.51 1437 15.13 23 7550 ZnO–B2O3–SiO2 (60 : 30 : 10) glass ,800 7.56 1439 15.48 221 7551 CaZnP2O7 900/2 h 7.56 63 100 282 27552 BaO–B2O3–SiO2 (42 : 45 : 13) glass 550 7.63 4100 6.65 7153 Mg3Sm4Al44O75zB2O3–SiO2–Al2O3 920 7.8 10 000 11 10054 Mg3(VO4)2 950/10 h 7.9 53 000 284 26855 CaO–B2O3–SiO2 (50.1 : 22.2 : 67.3 mol.-%) 900 7.9 2100 9.6 29256 CAS-T5 glass (CaO–Al2O3–SiO2–TiO2) 950 8.0 22 500 10 220 10357 Li2O–B2O3–SiO2–Al2O3–CaO 550 8 2400 248 16658 La2O3–2B2O3–0.5ZnO 900 8 72 000 13 – 7759 Li2O–B2O3–SiO2–Al2O3–CaO 550 8 2400 248 16660 MgZn2(VO4)2 800/5 h 8.1 38 600 2108 30061 60 wt-% La2O3–B2O3z40 wt-%Al2O3 850 8.1 4500 17.5 10962 MgTiO3–CaTiO3 (MMT-20)zSiO2–B2O3–BaO 875 8.2 3000 7 19863 BaWO4 1100 8.24 17 000 8 233 301, 30264 BaWO4z0.05 wt-%B2O3 950 8.25 32 700 285 30265 70 wt-% La2O3–B2O3z30 wt-%Al2O3 850 8.3 5500 17.2 10966 80 wt-% La2O3–B2O3z20 wt-%Al2O3 850 8.4 9800 17.6 10967 MgTiO3–CaTiO3 (MMT-20)–ZnO–B2O3–SiO2

(44.57 : 17.32 : 6.95 : 30.16)875 8.5 7000 7 6.2 255, 256

68 Li2O–B2O3–SiO2 frit glass ,800 8.5 1800 2157 200



Table 7 Continued

Sl no. Material


69 Li2MgSiO4 1000 8.5 30 000 15 255, 25670 Mn2SiO4 1100/N2 8.52 50 000 290 30371 MnMoO4 900 8.55 54 100 274 29872 ZnMoO4 800 8.67 49 900 287 29873 CaWO4z0.5 wt-%Bi2O3z9 wt-%H3BO3 850/0.5 h 8.7 70 220 215 30474 Ca–Al–B–Si–OzAl2O3 (K8) 870 8.7 900 3 – 30575 Mg3(VO4)2 950/25 h 8.8 61 900 293 26876 ZnO–B2O3–SiO2–MMT-20 (44.97 : 17.2 : 6.9 : 29.93) 900 8.9 810 8 215 19777 ZnO–B2O3–SiO2–MMT-20 (46.34 : 17.09 : 6.85 : 29.72) 900 8.9 7000 8 224 19778 ZnCu2Nb2O8 985 8.9 23 350 218 18579 ZnO–B2O3–SiO2–MMT-20 (49.21 : 16.15 : 6.49 : 28.15) 900 9 7000 8 262 19780 (ZrSn)TiO4z5 wt-%B2O3 1100/4 h 9 12 360 10.3 20281 Zn2V2O7 ,900 9 37 000 11 30682 MgTiO3–CaTiO3–ZnO–B2O3–SiO2 900 9 7000 7 255 19783 PbO–B2O3–SiO2 (30 : 60 : 10) glass ,800 9.06 1702 13.51 215 7584 K2O–B2O3–SiO2–CaO–SrO–BaO (glass)zAl2O3 900 9.1 600 0.5 0 11385 Mg3(VO4)2 950/50 h 9.1 64 140 293 26886 BaO–B2O3–SiO2 (50 : 40 : 10) glass ,800 9.15 1221 13.13 243– 7587 SmBO3 1100 9.3 11 000 9988 BaMoO4 900 9.3 37 200 279 29889 Mg3(VO4)2 1050 9.4 65 500 290 26890 MgCo2(VO4)2 900/5 h 9.4 78 900 295 26891 SrMoO4 1050 9.49 61 000 267 29892 MgCo2(VO4)2 930/5 h 9.6 55 300 83 30793 La2O3–2B2O3–0.5ZnOzLa2O3–3B2O3–0.5ZnO 900 9-10 72 000 13 7794 BaO–B2O3–SiO2 (50 : 30 : 20) glass 1100 9.52 1256 13.5 295 7595 BaO–B2O3–SiO2 (50 : 20 : 30) glass 1100 9.61 1315 14.3 2114 7596 ZnO–B2O3–SiO2–MMT-20 (44.77 : 17.59 : 7.05 : 30.59) 900 9.7 7000 8 8.8 19797 MgWO4 950 9.9 5400 30898 CAS-T10 glass (CaO–Al2O3–SiO2–TiO2) 950 10 22 500 10 215 10399 (ZrSn)TiO4z5 wt-%SiO2 1100/4 h 10 12 610 9.7 202100 TiO2–CaAlSi2O8 960/0.5 h 10 22 500 210 to 260 103101 0.83ZnAl2O4–0.17TiO2z10 wt-%BBSZ glass 950 10 10 000 223 309102 BaTeO3 800 10 34 000 254 310103 CAS-TB glass (CaO–Al2O3–SiO2–TiO2)z5 wt-%B2O3 950 10.5 14 200 10 220 103104 MgTiO3–CaTiO3 (MMT-20)zSiO2–B2O3–BaO 900 10.6 6000 7 198105 CaCu2Nb2O8–3V2O5 935 10.8 9300 216 186106 NdBO3 ,800 11 17 000 99107 0.7b-Ca2P2O7–0.3TiO2 1100/2 h 11 44 000 10 311108 (TiO2–B2O3–Ca–Al–Si) glass 960/0.5 h 11 1400 10 103109 PbO–B2O3 (40 : 60) glass 1100 11.11 1320 12.22 243 75110 NiCu2Nb2O8z3 wt-%V2O5 935 11.2 5760 211.7 186111 Cu3Nb2O8 985 11.2 25 560 23.7 186112 MgCu2Nb2O8z3 wt-%V2O5 935 11.3 2900 227 186113 ZnCu2Nb2O8z3 wt-%V2O5 935 11.4 10 200 223 186114 BaTi(BO3)2 1000/2 h 11.5 23 000 174115 Mg4(Nb22xVx)O9 (x50.0625) 1025 11.6 160 256 – – 240116 CaCu2Nb2O8 1110 11.6 2300 217 186117 0.6LiYW2O8–0.4BaWO4 900 11.7 19 750 14 302118 CaMoO4 1100 11.7 55 000 260 312119 Mg4NbTaO9 1100 11.8 281 673 266 313120 Mg4Nb1?5Ta0?5O9 1100 11.9 234 518 267 313121 CoCu2Nb2O8z3 wt-%V2O5 885 12 7530 218 186122 (ZrSn)TiO4z5 wt-% R2O–B2O3–SiO2 1100/4 h 12 14 400 9.6 202123 (ZrSn)TiO4z5 wt-% PbO–Al2O3–SiO2 1100/4 h 12 8110 8.1 202124 BaO–SrO–SiO2–ZrO2 ,1000 12 1000 5 98125 PbO–B2O3–SiO2 (40 : 20 : 40) glass 1100 12.11 1420 12.22 231 75126 Mg3CoNb2O9 1100/10 h 12.3 34 561 264 313127 LaBO3 1150 12.5 53 000 99128 Ba3(VO4)2z0.5 wt-%B2O3 950/5h 12.5 41 065 38.8 269129 Mg4Nb2O9z3 wt-%LiF 950/10 h 12.6 11 6418 272 239130 Mg3(VO4)2–0.5Ba3(VO4)2z0.0625 wt-%Li2CO3 950/5 h 12.6 74 450 25.8 314131 PbO–B2O3–SiO2 (40 : 40 : 20) glass 1100 12.74 1704 12.09 269 75132 NiCu2Nb2O8z3 wt-%V2O5 985 12.8 4240 481 186133 Mg3(VO4)2–0.5Ba3(VO4)2z0.0625 wt-%Li2CO3 950/5 h 13 74 000 26 315134 Mg2Co2Nb2O9 1100/10 h 13.2 12 461 251 313135 Ba2Ti9O20z50 vol.-%BaBSiO glass 900/0.5 h 13.2 1150 174136 MgWO4 1050 13.5 69 000 258 316137 ZnMnW2O8z0.005 mol.%B2O3 950 13.7 10 670 217 302



Table 7 Continued

Sl no. Material


138 PbO–B2O3–SiO2 (50 : 40 : 10) glass 1100 13.78 878 10.72 298 75139 80 wt-% La2O3–B2O3–TiO2 (20 : 60 : 20 mol.-%)

z20 wt-%BaNd2Ti5O14

850 14.2 9800 7.5 94 317

140 80 wt-% La2O3–B2O3–TiO2 (20 : 60 : 20 mol.-%)z20 wt-%BaNd2Ti5O14

800 14.5 9100 7.5 86 317

141 Zn3Nb2O8z3 wt-% 0.29BaCO3z0.71CuO 950 14.7 8200 8.3 184142 LiYW2O8z0.005 mol.%B2O3 900 14.8 9550 64 302143 MnWO4 1100 14.8 32 000 264 316144 (ZrSn)TiO4z5 wt-% 5ZnO–2B2O3 1100/4 h 15 23 660 9.1 202145 (ZrSn)TiO4z 5 wt-% Al2O3–SiO2 1100/4 h 15 8820 9.8 202146 Al2O3zCa–Al–B–Si–OzBa–(Sm,Nd)–Ti–O 870 15.1 2800 3 – 305147 PbO–B2O3–SiO2 (60 : 20 : 20) glass 1100 15.32 650 11.72 2124 75148 Cu3Nb2O8 900/2 h 15.6 48 400 275 183149 Mg4Nb2O9z3 wt-%LiFz6 wt-%CaTiO3 950/10 h 15.7 22 100 23 241150 MgCu2Nb2O8 1010 15.9 6780 246 186151 Zn3Nb2O8z3 wt-% 0.81MoO3z0.19CuO 950 15.9 10 200 8.2 158152 (0.4Bi2O3–La2O3–MgO–TiO2)–0.6La(Mg0?5Ti0?5)O3 900 15.9 14 300 35.3 319153 75 wt-% ZnNb2O6–TiO2z25 wt-% SiO2–B2O3–Al2O3 875 15.9 15 000 220 80154 (ZrSn)TiO4z5 wt-% Al2O3–B2O3–SiO2 1100/4 h 16 490 8.2 202155 (ZrSn)TiO4z5 wt-% ZnO–B2O3 1100/4 h 16 14 110 8.3 202156 CuNb2O6 1000 16.1 7100 7.4 245 318157 (Mg0?95Ca0?05)TiO3z3 mol.-%V2O5 1100 16.2 62 000 50 86158 CoCu2Nb2O8 985 16.6 36 800 237 186159 (Mg.095Ca0?05)TiO3z5 mol.-%V2O5 1000 16.6 13 700 49.9 86160 ZnCu2Nb2O8 900/2 h 16.7 41 000 277 179161 70 wt-% La2O3–B2O3–TiO2 (20 : 60 : 20 mol.-%)

z30 wt-%BaNd2Ti5O14

800 16.8 5900 7.1 109 317

162 Ba2TeO5 950 17 49 600 2124 310163 (ZrSn)TiO4z5 wt-% BaO–B2O3–SiO2 1100/4 h 17 12 460 8.9 202164 (ZrSn)TiO4z5 wt-% ZnO–B2O3–SiO2 1100/4 h 17 17 220 8.2 202165 CaTeO3 840 17.4 49 300 10 214166 BaTe4O9 500/2 h 17.5 54 700 290 215167 0.96MgTiO3–0.036SrTiO3z4 wt-%CuO 1070/2 h 17.5 25 100 320168 ZnWO4 1100 17.6 65 000 260 316169 MWF-38z10 wt-%(Li2O–B2O3–SiO2–CaO–Al2O3)

(28 : 27 : 30 : 5 : 10)875 17.7 3700 215 81

170 Ce2O2–WO3–TiO2 1025 17.8 13 100 6.214 85 321171 (Zr.8Sn.2)TiO4z10 wt-% BaO–B2O3–SiO2–Li2O–CuO 950/4 h 17.8 12 700 1.1 322172 (Zn0?6Mg0?4)TiO3z5 wt-% ZnO–B2O3–SiO2–Al2O3 1100 18 29 400 323173 MgTiO3z6 wt-% CuO–Bi2O3–V2O5 900 18.1 20 300 257 324174 (Zr0?8Sn0?2)TiO4z10 wt-%

BaO–B2O3–SiO2–Li2O–CuO950/8 h 18.4 10 500 20.3 322

175 BaNd2Ti5O14zLa2O3–B2O3–TiO2 750 18.4 6100 3.6 79176 Zn0?6Mg0?4TiO3z5 wt-% B–Si–Zn–K glass 950 19 18 950 323177 ZnTiO3 1100 19 30 000 10 255 221178 80 wt-%ZnNb2O6–TiO2z20 wt-% SiO2–B2O3–Al2O3 875 19.1 9600 9 80179 0.96MgTiO3–0.036SrTiO3z45 wt-%CuO 1070/2 h 19.1 1500 320180 85 wt-%ZnNb2O6–TiO2z15 wt-% CaO– B2O3–SiO2 875 19.2 11 000 17 80181 CaTe2O5 780 19.3 13 400 10 214182 TeO2 640/15 h 19.3 30 000 4 2119 210183 MgTi2O5z10 wt-%LBS glass 950/2 h 19.3 6800 – 216 166, 327184 90 wt-%ZnNb2O6–TiO2z10 wt-% SiO2–B2O3–Al2O3 900 19.5 9200 18 80185 ZnTiO3z0.25 wt-%V2O5 900 19.5 2700 7.4 325186 90 wt-%(Mg,Ca)TiO3z10 wt-% Li2O–B2O3–SiO2 950 19.5 26 700 212 326187 PbO–B2O3–SiO2 (70 : 20 : 10) glass 1100 19.57 505 10.32 2155 75188 LiYbW2O8z0.005 mol.%B2O3 900 19.7 8720 45 302189 BaNd2Ti5O14zLa2O3–B2O3–TiO2 850 19.9 8200 77 79190 Ca[(Li1/3Nb2/3)0?95Ti0?05]O3-d z5 wt-%Bi2O3 900/3 h 20 6500 24 233191 Li2?081Ti0?676Nb0?243O3 1100 20.02 49 700 13 252192 90 wt-%ZnNb2O6–TiO2z10 wt-% Li2O–B2O3–SiO2 875 20.3 8200 5 80193 ZnTiO3z0.5 wt-%V2O5 900 20.3 5200 7.76 325194 MgTiO3z5 mol.-%Bi2O3–7 mol.-%V2O5 875 20.6 10 420 6.3 194195 ZnTiO3z0.75 wt-%V2O5 900 20.6 8800 8.2 325196 Li2?081Ti0?676Nb0?243O3z1.5 wt-%B2O3 880 20.9 34 100 8.3 252197 ZnTiO3 925 21 30 000 290 225198 BaTe2O6 650 21 50 300 251 310199 ZnTiO3z1 wt-%V2O5 900 21.3 8000 8.8 325200 Ca[(Li0?33Nb0?67)0?9Ti0?1]O32dz20 wt-%LiF 840 21.3 20 450 4.59 218 328201 5Li2O–0.583Nb2O5–3.248TiO2z1 wt-%V2O5 920 21.5 32 950 6.1 254



Table 7 Continued

Sl no. Material


202 85 wt-%Ba5Nb4O15z15 wt-%Li2O–B2O3–SiO2–CaO–Al2O3

875 21.5 3400 215 326

203 90 wt-%CaZrO3z10 wt-% Li2O–B2O3–SiO2 875 21.9 4700 258 326204 (Zn0?7Mg0?3)TiO3 950 22 65 000 280 225205 Li2?081Ti0?676Nb0?243O3z0.5 wt-%B2O3 880 22 32 000 9.5 178206 CaLa8Ti9O31z3 wt-% Bi2O3–B2O3z0.5 wt-%LiF 950 22 6500 5 1 329207 ZnTiO3z5 wt-% B2O3–SiO2 850 22.2 52 400 6 330209 Zn12xMgxTiO3 950 22–26 60 000 280 to z20 225210 Zn3Nb2O8z2 mol.-%V2O5 850–1000 22.4 67 500 185211 ZnNb2O6z5 wt-%CuO 925/2 h 22.1 59 500 265 179212 CoNb2O6 1100 22.8 11 300 245 178213 CaTiO3–CaZrO3–frit glass (70 : 15 : 15) 875 23 2400 0 200214 CeO2–CoO4–TiO2z0.5 wt-%CuO 1050 23 45 000 255 339215 Zn(Nb12xVx/2)2O622?5x (x50.15) 975/2 h 23.3 37 000 271 181216 ZnNb2O6z5 wt-%CuOz4B2O3 900 23.3 46 800 26.7 331217 Ca(Li1/3Ta2/3)O3-dz6 wt-%B2O3 1100 23.33 27 900 10.99 174218 Zn0?95Mg0?05TiO3z0.25TiO2z1 wt-% 3ZnO–B2O3 940/2 h 23.6 30 990 7.75 28 226219 Zn(Nb12xVx/2)2O622?5x (x50.025) 1000/2 h 23.8 64 000 250 181220 Zn(Nb0?94V0?06)2O6 875/2 h 23.9 65 000 272 180221 BaO–TiO2–WO3z5 wt-% 5ZnO–2B2O3 1100 24 13 000 9.4 105222 Ca(Li1/3Ta2/3)O3-dz3 wt-%B2O3 1100 24 40 300 10.86 230223 Ca(Li1/3Ta2/3)O3-dz1 wt-%B2O3 1100 24.1 38 900 10.8 230224 Zn0?95Mg0?05TiO3z0.25TiO2z1 wt-% 3ZnO–B2O3 880 24.6 4000 214 227225 Ca[(Li0?33Nb0?67)0?9Ti0?1]O32dz10 wt-%LiF 900 24.8 19 300 4.16 215 328226 CaO–ZrO2–glass 25 3500 98227 BaO–TiO2–WO3 (N-35)z5 wt-% PbO–SiO2–B2O3 1100 25 6500 6 – 105, 332228 CaO–ZrO–glass ,1100 25 3500 5 98229 (Zr0?8Sn0?2)TiO4z10 wt-%


230 BaO–TiO2–WO3 (N-35)z5 wt-% BaO–SiO2–B2O3 1100 26 8400 6.1 – 105, 332231 MWF-38z10 wt-% Li2O–B2O3–SiO2–CaO–Al2O3

(52.45 : 31.06 : 11.99 : 2 : 2.5)875 26 10 200 24 81

232 Ba(Zn1/3Ta2/3)O3z5 mol.-%B2O3z10 mol.-%CuO 870/2 h 26 11 000 0 333233 85 wt-%BaTi4O9z15 wt-%

Li2O–B2O3–SiO2–CaO–Al2O3

875 26 10 200 0 326

234 Ca[(Li1/3Ta2/3)0?95Ti0?05]O32d z3 wt-%B2O3 1050/4 h 26.1 22 000 10.3 297 230235 BaO–Sm2O3–4TiO2z10 wt-%B2O3 1100/2 h 26.5 11 800 29.5 164236 (Zr0?8Sn0?2)TiO4z10 wt-%


237 BaO–TiO2–WO3 (N-35)z5 wt-% ZnO–B2O3–SiO2 1000 27 8400 7.0 105, 332238 BaO–TiO2–WO3 (N-35)z5 wt-% PbO–Al2O3–SiO2 1100 27 8400 6.1 – 105, 332239 ZnO–TiO2z2 wt-%ZBS glass 900/3 h 27 19 400 6 2 223240 BaTi4O9zB2O3–ZnO–La2O3 glass 900 27 20 000 6.5 334241 Ba2Ti9O20z1 wt-% ZnO–B2O3 940/2 h 27.3 8300 7.2 2.5 335, 336242 Ba(Mg1/3Nb2/3)O3zB2O3 900 27.5 8500 27 273243 90 wt-%(Zr,Sn)TiO4z10 wt-% Li2O–B2O3–SiO2 875 27.5 9000 14 326244 ZnTiO3–0.25TiO2 925 27.5 14 000 220 222245 Ca[(Li1/3Ta2/3)0?9–Ti0?1]O32dz3 wt-%B2O3 1000/4 h 27.6 9800 10.2 – 230246 BaTi4O9–10 mol.-% BaO–ZnO–B2O3 glass 925 28–33 20 000 6.6 74247 Ba2Ti9O20z3 wt-%B2O3 940/2 h 28.3 10 800 28.2 337248 Ca[(Li1/3Ta2/3)0?8Ti0?2]O32dz3 wt-%B2O3 1050 28.4 12 900 9.9 215 230249 (Pb123x/2Lax)(Mg1/2W1/2)O3 (x50.56) 1100 28.7 18 100 26 338250 BaO–TiO2–WO3 (N-35)zZnO–B2O3 1100 29 7000 5.8 – 105, 332251 BaO–TiO2–WO3 (N-35)z5 wt-% ZnO–B2O3 1100 29 6500 5.8 105, 332252 BaTiTe3O9 650 29 1700 7.6 2372 213253 Ca[(Li1/3Ta2/3)0?85Ti0?15]O32dz3 wt-%B2O3 1050/4 h 29.45 20 700 10.47 257 230254 ZnTiO3z0.25TiO2z1 wt-%B2O3 875/4 h 30 56 000 10 222255 Bi2ZnNb2O9zZnNb2O6z3 wt-%

PbO–Bi2O3–B2O3–ZnO–TiO2 glass900 30 3500 6 150

256 Ba2Ti9O20z9 wt-%B2O3 1050/2 h 30 13 700 6 175257 0.15TiTe3O8–0.85TeO2 700 30 22 000 5 0 210259 (Ca12xNd2x/3)TiO3z3ZnO–2B2O3 glass

(20–40 mol.-%)880 30–60 200–5500 20–60 238

260 MWF-38z10 wt-% Li2O–B2O3–SiO2

(56.92 : 37.59 : 5.49)875 30.2 9500 3 81

261 Ca(Li1/3Nb2/3)O32dz4 wt-%B2O3 1000 30.6 31 000 217.5 229262 BaO–TiO2–WO3 (N-35)z5 wt-% Al2O3–SiO2–B2O3 1100 31 5400 5.7 – 81, 221263 Ba(Mg1/3Nb2/3)O3z2 mol.-%B2O3z10 mol.-%CuO 875/2 h 31 21 500 221.3 274264 BaO–Sm2O3–4TiO2z10 wt-%BaB2O4 1100/2 h 31 7700 29.5 164



Table 7 Continued

Sl no. Material


266 (Zr0?8Sn0?2)TiO4z10 wt-%BaO–B2O3–SiO2–Li2O–CuO

1050/4 h 31.4 32 200 21.4 322

267 (Zr0?8Sn0?2)TiO4z10 wt-%BaO–B2O3–SiO2–Li2O–CuO

1050/12 h 31.7 29 700 21.8 322

268 90 wt-%BaTi4O9z10 wt-% Li2O–B2O3–SiO2 875 31.7 9000 10 326269 MBRT-90z10 wt-% Li2O–B2O3–SiO2–CaO–Al2O3

(28 : 27 : 30 : 5 : 10)875 31.9 2200 20 81

270 BaO–TiO2–WO3 (N-35)z5 wt-% Al2O3–SiO2 1100 32 11 000 5.6 – 105, 332271 SnTe3O8 700/15 h 32 13 200 4 177272 Ba(Zn1/3Nb2/3)O3z5 mol.-%B2O 900 32 3500 20 340273 BaTi4O9z10 wt-% glass frit 875 32 9000 10 176274 BaTi4O9z12 mol.-%BaCu2(B2O5) 875/2 h 32 10 800 32 299275 CaWO4z0.005 mol.%B2O3 1050 32.7 70 600 247 302276 Bi6Te2O15 (oxygen atm) 800/15 h 33 41 000 285 216277 BaTi4O9z5 wt-% ZnO–B2O3 glass 900/2 h 33 27 000 7 341278 93 wt-%BaTi4O9z10 wt-% Li2O–B2O3–SiO2 950 33.8 12 700 25 326279 LiNb3O8 1075/3 h 34 58 000 296 342280 0.2TiTe3O8–0.8TeO2 670 34 22 000 24 210281 Ca[(Li1/3Nb2/3)0?84Ti0?16]O32dz2 wt-%LiF

z3 wt-%ZBS900 34.3 17 400 24.6 343

282 BiNbO4z0.03 wt-%CuV2O6 1050 34.9 16 100 23.4 344283 Ca[(Li1/3Ta2/3)0?7Ti0?3]O32dz3 wt-%B2O3 1050 35 22 800 9.45 24 230284 Ca[(Li1/3Nb2/3)0?9Ti0?1]O32dz0.7 wt-%B2O3 1000 35 22 100 25 231285 Ca[(Li1/3Nb2/3)0?8Ti0?2]O32dz5 wt-%Bi2O3 900/3 h 35 11 000 13 233286 2.5ZnO–0.5CeO2–4.5TiO2–2.5Nb2O5

z2 wt-%FeVO4

1100 35 12 000 250 345

287 TiTe3O8 700/5 h 36 10 200 4 177288 Ba2Ti9O20z9 wt-%BaB2O4 1050/2 h 36 12 600 22 175289 Ba(Zn1/3Nb2/3)O3z5 mol.-%B2O3zCuO 875 36 19 000 21 340290 Li2O–Nb2O5–TiO2z1 wt-%B2O3 1100 36 10 450 5.9 12.2 253291 BaTi4O9z2 mol.-%B2O3z5 mol.-%CuO 900/2 h 36.3 30 500 28 346292 BaO–TiO2–WO3 1100 37 53 000 6 2x 347293 Bi12(B0?5P0?5)O20 780 37.4 850 219 217294 0.42ZnNb2O6–0.58TiO2z10 wt-%CuO 875 37 17 000 27 348295 Bi12SiO20 850 37.6 8100 220 217296 Bi12GeO20 850 38 7800 231 217297 (Zr0?8Sn0?2)TiO4z2.5 wt-%BaCuO2zCuO 1000 38 35 000 70298 Bi12PbO19 850 38.6 2900 284 217299 Bi2Te2O8 (oxygen atm) 650/10 h 39 23 000 243 216300 Bi12MnO202d 720 39.4 800 235 217301 Ba5Nb4O15z3 wt-%B2O3 925/2 h 39 18 700 0 349302 Ca[(Li1/3Nb2/3)0?8Ti0?2]O32dzB2O3zBi2O3 920 40 20 500 8 4.7 350303 Ca[(Li1/3Nb2/3)0?8Ti0?2]O32dz12 wt-%

B2O3–ZnO–SiO2–PbO frit glass900 40 12 500 28 234

304 Ba5Nb4O15z0.3 wt-%ZnB2O4 glass 900 40 12 100 48 351305 Ba–Nd–Sm–Bi–Ti–Oz9 wt-% BaO–B2O3–SiO2 950/2.5 h 40 3000 169306 Ba3Ti5Nb6O28z3 wt-%B2O3–1 wt-%CuO 900/2 h 40.3 32 500 – 9 352307 BiNb0?6Sb0?4O4 920 40.7 9500 231 153308 (T0i.8Sn0?2)Te3O8 700/5 h 41 22 000 4 177309 Bi0?95Sm0?05NbO4 1040 41 5200 2200 154310 Bi12TO20 850 41 3300 232 217311 0.9BiNbO4–0.12ZnNb2O6z1.2 wt-%CuV2O6 850 41 28 120 4 155312 2.5ZnO–0.5ZrO2–4.5TiO2–2.5Nb2O5z2 wt-%FeVO4 1100 41 25 000 215 337313 Bi12TiO20 800 41 3300 232 217314 Li2O–Nb2O5–TiO2 (5 : 1 : 5)z1 wt-%B2O3 900 41.3 9320 353315 BiNbO4 : 0.4 wt-%B2O3 960/2 h 41.5 21 000 22.4 354316 BaNb12xMoxO4 (x50.01) 950 41.8 3500 215 355317 0.84Ba5Nb4O15–0.16BaNb2O6z0.3 wt-%B2O3 900 42 28 000 0 190, 191318 BaNb2O6 (hex) 1050 42 4000 2800 190, 191319 Ba0?79Sr0?21Ti5O11 (hot pressed) (jp) 1050/72 h 42 39 000 10 44 356320 [Ca0?6(Li0?5Nd0?5)0?4]0?45Zn0?55TiO3 z2 wt-%

0.3ZnO–0.67H3BO3

875/4 h 42 10 300 19.5 236

321 ZnO–Nb2O5–TiO2–SnO2z1.5 wt-% CuO–V2O5 860 42.3 9000 8 357322 BiNbO4 875 43 15 700 4.3 38 29, 156323 BiNbO4z0.043 wt-%CuOz0.05 wt-%V2O5 875 43 4260 4.3 3 29324 Ca[(Li1/3Nb2/3)0?7Ti0?3]O32dz6 wt-%Bi2O3

–2 wt-%B2O3

920 43.1 10 600 7.68 10 218

325 Ca[(Li1/3Nb2/3)0?7Ti0?3]O32dz3 wt-%Bi2O3

–2 wt-%B2O3

940 43.1 12 900 7.73 53.7 350



Table 7 Continued

Sl no. Material


326 BiNbO4z0.5 wt-%CuO 900 43.3 13 000 6.3 15 157327 Bi0?99La0?01NbO4 920 43.36 10 600 7 22 158328 BiTaO4 950 43.5 12 000 240 159329 Bi0?99(La0?38Nd0?62)0?01NbO4 820 43.57 12 323 12.8 160330 Ca[(Li1/3Nb2/3)0?7Ti0?3]O32dz1 wt-%Bi2O3

z1 wt-%B2O3

960 43.9 16 600 7.6 35 350

331 2.5ZnO–0.2SnO2–4.8TiO2–2.5Nb2O5

z2 wt-%FeVO4

900 44 13 000 29 345

332 BiNbO4z0.5 wt-%V2O5 895 44 15 800 7 18 250, 161333 BiNb0?95Sb0?05O4 880 44.49 14 278 25.2 153334 BiNb0?88Ta0?12O4z0.5 wt-%CuO 920 44.5 14 000 20.2 157335 BiNbO4z0.03 wt-%CuV2O6 (ortho) 1000 44.9 16 100 23.4 344336 2.5ZnO–0.5SnO2–4.5TiO2–2.5Nb2O5

z2 wt-%FeVO4

900 45 17 500 225 345

337 Ca[(Li1/3Ta2/3)0?5Ti0?5]O32dz3 wt-%B2O3 1050 45 12 300 8 75 230338 7Bi2O3–2TeO2 (oxygen atm) 750/15 h 46 1100 2144 216339 0.65LiNb3O8–035TiO2 1100 46.2 5800 0 342340 Bi2Ti4O11 1100 47 4800 2540 377341 Ca[Li(12x)/3Nb(12x)/3Ti3x]O32dzLi2OzB2O3 (x50.1) 940 47 8100 358342 Ca2Zn4Ti16O38 1100 48.4 31 600 6.7 48 359343 Ba4Sm9?33Ti18O54z0.6 wt-% 0.4Bi2O3–0.6B2O3 1050 49 7700 4.3 225 360344 11Li2O–3Nb2O5–12TiO2z0.5 wt-%B2O3 900 49.2 8800 57.6 361345 Ca[(Li1/3Nb2/3)0?9Ti0?3]O32dz1 wt-%B2O3 940 50 6500 27.6 232346 TiTe3O8 720 50 30 600 5 133 210347 Ba4Sm9?33Ti18O54z1 wt-% 0.4Bi2O3–0.6B2O3 1050 51.7 7600 4.3 223 360348 Bi2(Zn1/3Ta2/3)2O7 850 51.8 2600 226 362349 CaTi0?5(Fe0?5Nb0?5)0?5O3z3 wt-%B2O3 900/2 h 52.3 2930 13 363350 MBRT-90z10 wt-% Li2O–B2O3–SiO2 (56.92 : 37.59) 875 55.3 2500 26 81351 Bi2TeO6 (oxygen atm) 720/15 h 56 10 400 249 216352 Li1zx2yNb12x2yTixz4yO3 (x50.1, y50.15) 1100/1 h 56.19 8345 6.02 15 250, 364353 Bi2O3–CaO–Nb2O5 (46.15 : 23.08 : 30.77) 950 57 470 3.7 24 29354 2.5ZnO–5TiO2–2.5Nb2O5 1100 58 16 300 210 345355 Bi2O3–CaO–Nb2O5 (45.75 : 21.75 : 32.5) 1050 58 1060 3.8 20 29356 Li1zx-yNb12x2yTixz4yO3 (x50.05, y50.1) 1100/1 h 58.45 6233 6.3 231 248, 250357 Bi18Ca8Nb12O65 950 59 610 3.7 25 29358 Li1zx2yNb12x2yTixz4yO3 (x50.1, y50.125) 1100/1 h 59.16 7565 6.05 22 248, 250359 BaSm2Ti4O12z16 mol.-%BaCu(B2O5) 875/2 h 60 4500 230 165360 MBRT-90z10 wt-% Li2O–B2O3–SiO2–CaO–Al2O3

(52.45 : 31.06 : 11.99 : 2 : 2.5)875 61.6 2500 18 81

361 0.83Bi2O3–0.25Nb2O5 900/3 h 62 560 2372 365362 0.9Bi2O3–0.1Nb2O5 900/3 h 62 800 2234 365363 (Pb0?4Ca0?6)(Fe0?5Ta0?5)O3 (mechanochemical) 1050/3 h 62 9000 215 366364 Bi2Zn2/3Ta4/3O7z0.05 wt-%CuOz0.05 wt-%V2O5 930 63 6800 5.35 145365 Bi2(Zn1/3Ta2/3)2O7 1050 63.6 6100 233.7 362366 Bi2(Zn1/3Ta2/3)2O7z0.5 wt-%B2O3 850 63.9 3500 214 362367 Li1zx2yNb12x2yTixz4yO3 (x50.15, y50.075) 1100/1 h 64.04 4612 5.92 215 248, 250368 Li1zx2yNb12x2yTixz4yO3 (x50.1, y50.1) 1100/1 h 64.79 6385 5.7 8 250, 366369 LiNb0?6Ti0?5O3z0.5 wt-% 0.17Li2O–0.83V2O5 850 64.7 5900 9.4 367370 Ba3Ti4Nb4O21z1 wt-%B2O3z3 wt-%CuO 900/2 h 65 16 000 101 368371 0.1Pb(Fe2/3W1/3)O3–0.9Pb.2Ca.8(Fe1/2Nb1/2)O3 1000 65.3 2270 224 260372 Li1zx2yNb12x2yTixz4yO3 (x50.1, y50.1)

z2 wt-%V2O5

900/1 h 66 3800 5.6 11 249

373 Bi2O3–CaO–Nb2O5 (52.5 : 17.5 : 30) 925 66 330 3.6 35 29374 Bi2(Zn1/3Ta2/3)2O7 850 66.3 3200 28.8 145375 BaNd2Ti4O12zB2O3–Bi2O3–SiO2–ZnO

glasszLa2O3–B2O3–TiO2

900 67 6000 6 4 85

376 (Pb0?5Ca0?5)(Fe0?5Ta0?5)O3 1100 67.9 5680 369377 ZrTe3O8 700/15 h 68 950 4 177378 BaO–(Nd0?8Bi0?2)2O3–4TiO2z10 wt-%

Li2O–B2O3–SiO2–Al2O3–CaO glass900 68 2200 55 166

379 Bi2(Zn1/3Nb2/3)2O7z1 wt-% of 0.15CuO–0.85MoO3 900 70 4800 3 147380 LiNb0?6Ti0?5O3z1 wt-%B2O3 880 70 5400 26 370381 0.2Pb(Fe2/3W1/3)O3–0.8Pb0?2Ca0?8(Fe1/2Nb1/2)O3 1000 71.4 1520 229 260382 TiO2zzinc borosilcate glass 90072 h 74 8000 340 121383 Bi2(Zn1/3Nb2/3)2O7 950/2 h 76.2 2980 148384 Li1zx2yNb12x2yTixz4yO3 (x50.15, y50) 1100/1 h 76.21 997 5.32 262 248, 313385 Ba4Sm9?33Ti18O54z0.5 wt-%GeO2 950 77.3 8900 219 371386 Li1zx2yNb12x2yTixz4yO3 (x50.05, y50.05) 1100/1 h 77.76 2184 5.2 242 248, 250387 Bi2(Zn1/3Nb2/32xVx)2O7 (x50.001) 850/2 h 78.55 3780 148



of 12 400 GHz. The results, however, demonstrated thatthe firing temperature is a dominant factor in controllingthe dielectric properties due to formation of crystallinephases at certain temperatures and should thus becarefully controlled.

Dai et al.113 in Motorola developed a low loss andnear zero tf LTCC (T2000) based on alumina. This workforms a good example how zero tf can be achieved bycompensating the large negative tf of a basic dielectricceramic or glass–ceramic composites with TiO2 havinga positive one. X-ray diffraction study revealed thatduring sintering, Al2O3 reacted with the glass andformed anorthite type crystalline phases MSi2Al2O8

(M5Ca, Sr or Ba). The consumption of SiO2, CaO, SrOand BaO to form anorthite greatly decreased the volumeof glass in the final structure and results in high dielectricQ. The dissolution of Al2O3 into the glass andsubsequent formation of crystalline phases via a diffu-sion process were observed.114,115 The T2000 dielectrichas er59?1 and Qf52500 GHz. Figure 5 shows how thetf of T2000 can be adjusted over a wide range depending

on the amount of TiO2 in the formulation. The dielectrichas tf of 280 ppm K21 in the absence of TiO2.Extensive study using TEM and EDS analysis showed

Table 7 Continued

Sl no. Material


388 Bi2(Zn1/3Nb2/32xVx)2O7 (x50.003) 850/2 h 78.62 3480 148389 Bi18(Ca12xZnx)8Nb12O65 (x50.725) 925 79 1000 3.2 1 29390 0.8Bi2O3–0.3Nb2O5 920/3 h 80 420 2306 365391 Bi2O3–TiO2 (1 : 11.3)z0.112 wt-%CuO 915/2 h 81 8900 0 372392 (Pb0?45Ca0?55)[(Fe0?5Nb0?5)0?9Sn0?1]O3

z0.2 wt-%CuOz0.1 wt-%Bi2O3

1000/3 h 83 6085 8 261

393 (Pb0?45Ca0?55)[(Fe0?5Nb0?5)0?9Sn0?1]O3

z0.2 wt-%CuOz0.4 wt-%Bi2O3

1000/3 h 86 4340 8 261

394 0.74Bi2O3–0.26Nb2O5 900/2 h 86 1000 120 365395 0.2Pb(Fe2/3W1/3)O3–0.8Pb.3Ca0?7(Fe1/2Nb1/2)O3 930 91.3 1650 24 260396 (12x)Ca2/5Sm2/5TiO3–xLi1/2Nd1/2TiO3 (x50.3) 1100/3 h 87 4600 373397 0.05Pb(Fe2/3W1/3)O3–0.95Pb0?4Ca0?6(Fe1/2Nb1/2)O3 1000 88.4 3800 26 260398 (Pb0?45Ca0?55)[(Fe0?5Nb0?5)0?9Sn0?1]O3

z5 wt-% BiO3–LiF950 89 800 215 364

399 0.75Bi2O3–0.25Nb2O5 900/3 h 90 630 60 167400 Bi3NbO7 940 91 730 100 374401 (Pb0?5Ca0?5)0?92La0?08[Fe0?5Nb0?5]O3zBi2O3–MnO2 1050/4 h 91.1 4870 18.5 263402 0.3Pb(Fe2/3W1/3)O3–0.7Pb0?2Ca0?8(Fe1/2Nb1/2)O3 1000 91.3 1650 7.3 260403 (Pb0?45Ca0?55)(Fe0?5Nb0?5)O3 1100/3 h 92.7 5970 375404 0.75Bi2O3–0.25Nb2O5 850/3 h 92 725 96 365405 PbCa(Fe,W,Nb)O3 1000 95.7 3840 9.6 260406 TiO2z2 wt-%CuO 900/2 h 98 14 000 374 119407 0.75Bi2O3–0.25Nb2O5 930/3 h 98 300 2154 365408 0.05Pb(Fe2/3W1/3)O3–0.95Pb0?45Ca0?55(Fe1/2Nb1/2)O3 1000 100.8 3250 20 260409 [(Pb1/2Ca1/2)0?95La0?05](Fe1/2Nb1/2)O3 z1 wt-%

PbO–B2O3–V2O5 glass1050/3 h 101 5400 5 5.9 235

410 Bi1?733(Zn0?733Nb4/3)O6?67 1000 101 4800 4.77 376411 0.2Pb(Fe2/3W1/3)O3–0.8Pb0?4Ca0?6(Fe1/2Nb1/2)O3 930 107.2 3790 48 260412 0.1Pb(Fe2/3W1/3)O3–0.9Pb0?45Ca0?55(Fe1/2Nb1/2)O3 930 109.4 3500 52 260413 0.05Pb(Fe2/3W1/3)O3–0.95Pb0?5Ca0?5(Fe1/2Nb1/2)O3 1000 112.2 2734 52 260414 Bi1?5Zn0?92Nb1?5O6?92z3 wt-% 0.81MoO3–0.19CuO 900/4 h 118.2 1000 2.3 184, 360415 Bi1?5Zn0?92Nb1?5O6?92z3 wt-% 0.21BaCO3–0.79CuO 950/4 h 120.1 1050 2.3 184, 360416 Bi1?5Zn0?92Nb1?5O6?92 1050/4 h 126.2 520 2.4 184417 0.2Pb(Fe2/3W1/3)O3–0.8Pb0?45Ca0?55(Fe1/2Nb1/2)O3 930 127.2 2300 96 260418 (PbCa)(FeW,Nb)O3 930 128 2600 97 260, 296419 Bi1?5Zn0?92Nb1?5O6?92z0.6 wt-%V2O5 850/1 h 148.0 120 184420 Ag(Nb2/4Ta2/4)O3 1200 285 300 2.39 247421 Ag(Nb1/4Ta3/4)O3 925 295 600 2.6 247422 Ag(Nb2/4Ta2/4)O3z1 wt-%CuO 900 398 400 2.248 247423 Ag(Nb3/4Ta1/4)O3–Ag(Nb1/4Ta3/4)O3 (45 : 55) 925 463 200 1.97 247424 Ag(Nb3/4Ta1/4)O3 925 487 200 1.89 247

5 Variation of resonant frequency with and without TiO2

addition in T2000 glass–ceramic system113



the presence of a significant amount of titanium in thecrystalline phase as well as in the embedded glass matrix.They suggested that during sintering, part of the TiO2

dissolves into the glass matrix and acts as nucleationagents for the subsequent growth of the titanium richcrystalline phases. The compensating mechanism ofTiO2 for tf can be significantly different from that of aTiO2 addition to a non-reactive LTCC dielectric. Daiet al.113–115 proposed that the tf of T2000 is adjusted bya combination of residual TiO2, titanium in the glassmatrix and the titanium rich crystalline phases. Thedissolved titanium and subsequently formed titaniumcompounds probably have much higher positive tf valuethan TiO2, contributing to more adjustment of tf. Inthe case of LTCC dielectrics in which TiO2 remainsunreacted nearly double the amount of TiO2 is needed toachieve zero tf. The tf of T2000 dielectric can bedecreased to near 0 ppm K21 by incorporating arelatively small amount of TiO2 into the composition.The TiO2 dissolves into the glass during sintering andforms titanium rich plate like crystalline phases via anucleation and growth process. This process makes thetf modification more efficient than a simple mixing ofTiO2 into the composition.

TiO2

The TiO2 is widely researched as a basic ceramic for highpermittivity LTCCs. Several approaches including mono-sized116 or nanosized117 TiO2 have been attempted tosinter the TiO2 ceramics at temperatures lower than1000uC. Kim et al. in 1992 reported118 that the additionof CuO to anatase significantly lowered the sinteringtemperature. The final composition was a mixture of CuOand rutile119 and with 2 wt-% addition of CuO sintered at900uC for 2 h, the er, Qf and tf of 98, 14 000 GHz and374 ppm K21 were achieved respectively.

Several authors studied120–123 TiO2 with BSG and arethe most commonly used glass materials in glasszcera-mic composites for microelectronic packaging. Yoonet al.121 prepared compositions of TiO2 in anastaseform, modified borosilicate glasses (BSG and ZBSG)and studied their sintering behaviour, phase evolutionand microwave properties. The results showed that thewetting behaviour of a glass with the basic ceramic hasan important role and should be carefully studied. It wasfound that BSG did not react with TiO2 but ZBSGreacted with TiO2 forming second phase of Zn2SiO4

having also a clear effect on the microwave properties ofthe composition (Fig. 6). Thus the highest Qf(,11 000 GHz) value was achieved with the non-reactive system (TiO2 with BSG), but at the same time,the material showed low relative permittivity (,55). Inboth cases, however, the tf kept undesired high valueover 300 ppm K21. On the other hand, Jean and Lin122

studied the effects of borosilicate addition on thedensification and dielectric and thermal expansionproperties of TiO2 both in rutile and anatase phases.They reported that anatase has better wetting propertieswith BSG and hence results in larger densification thanrutile.122 The densification was controlled by viscousflow of BSG. Figure 7 shows the variation of CTE andvolume fraction of rutile VR formed as a function ofsintering time for 40 vol.-%BSG and 60 vol.-% anataseand fired at 875uC for 1 h. The results show that CTEand VR increased with increasing firing time122 which isclear since the rutile has a higher CTE than anatase.124

Other results reported mainly relate to use of TiO2

as filling particles to modify the tf value or nucleationof different glasses. Yano et al.120 reported themodification of tf by adding TiO2 in glass–ceramic inwhich the reaction of TiO2 with glass was purposelyminimised by coarsening the TiO2 particles via heattreatment. They reported that 15 wt-%TiO2 was neces-sary to decrease the original tf of an undoped LTCCdielectric at 250 ppm K21 to almost 0 ppm K21.Miyauchi and Arashi125 investigated the composition0?15 vol.-%Al2O3, 0?15 vol.-%TiO2 and 0?7 vol.-% Sr–Mg–Ca–Si–Al–B–O glass with several average particlesizes of TiO2. The results showed that the viscosity of theglass–ceramics increased with decreasing TiO2 averageparticle size and the effect was attributed to the abilityof smaller particles to more effectively obstruct glassliquefaction.125

Additionally, the anorthite (CaO–Al2O3–2SiO2:CaAl2Si2O8) predominant glass–ceramic system with

a quality factor; b temperature coefficient of resonantfrequency; c relative permittivity

6 Microwave dielectric properties of low temperature sin-

tered TiO2 with BSG and ZBSG as function of sintering

temperature121

7 Coefficient of thermal expansion and VR of composi-

tion with 40 vol.-%BSG and 60 vol.-% anatase as func-

tion of sintering duration at 875uC122



TiO2 has been extensively investigated and regarded as apotential material for LTCC applications.103,126–129 Thisis clear since the anorthite is an important material forLTCC substrates due to its lower CTE and lowerrelative permittivity than alumina.127 Lo et al.130 andMarques et al.131 reported a low temperature anorthiteglass–ceramic by reducing the particle size of glasspowders to the submicrometre scale. With this glass,also TiO2 has been reported to play the role ofnucleating agents to reduce the crystallisation tempera-ture lower than 900uC.129 Lo et al.103 investigated thesintering behaviour of TiO2 nucleated anorthite basedglass–ceramics using three different compositions (CAS-T10: CaO–Al2O3–SiO2–TiO2, 18?16 : 32?94 : 38?9 : 10;CAS-TB: 17?24 : 31?3 : 36?96 : 10 : 5B2O3; CAS-T5:19?17 : 34?77 : 41?06 : 5). The results showed that theanorthite glass densified and crystallised on sintering aty950uC and the glass–ceramic showed a CTE in therange 4–5 ppm K21 which is very close to silicon. Therelative permittivity of the composition, however,increased with TiO2 content, but in this case, thetemperature dependence of the permittivity was onlyslightly influenced.

Bi2O3 based compoundsAmong the bismuth based ceramics, Bi2O3–ZnO–Nb2O5

(BZN) ternary oxides received considerable attention.Several research groups132–135 studied the structure and

properties of BiO–ZnO–Nb2O5 ceramics. There are twomain phases in BZN, a cubic pyrochlore phaseBi1?5ZnNb1?5O7 (a-phase) with er y150 and tf about2400 ppm K21, and a monoclinic zirconolite like phaseBi2Zn2/3Nb4/3O7 (b-phase) with er y80 and tf aboutz150 ppm K21. Several authors136–139 reported thatBZN are temperature stable dielectric suitable for thecapacitor industry with sintering temperature ofy1000uC. Yan et al.137 proposed that the sinteringtemperature can be further lowered below 950uC byincorporating Bi2O3–NiO–Nb2O5 into BZN ceramics.Several authors investigated the microwave dielectricproperties of Bi2O3–ZnO–Nb2O5/Ta2O5 ceramics.140–143

Figure 8 shows the XRD pattern of Bi2(Zn1/3Ta2/3)2O7

calcined at different temperatures in the range 900–1100uC. Several authors143–149 reported that the sinter-ing temperature can be lowered by suitable doping, suchas B2O3, V2O5, CuO–V2O5, BaCO3–CuO, MoO3–CuO,PbO–Bi2O3–B2O3–ZnO–TiO2, etc. The 0?5 wt-% addi-tion of B2O3 lower the sintering temperature of Bi2(Zn1/

3Ta2/3)2O7 to y850uC forming low temperature mono-clinic phase with er5y63 and Qf53500 GHz andtf5214 ppm K21.143 Although vanadate based addi-tion lower the sintering temperature considerably, itmust be noted that silver is reactive136,150 with V2O5 andhence not suitable for LTCC. Youn et al.134 formulatedhigh relative permittivity bismuth pyrochlore dielectriccomposition with low dielectric loss at microwave

a 900uC; b 950uC; c 1000uC; d 1050uC; e 1100uC8 X-ray diffraction patterns of Bi2(Zn1/3Ta2/3)2O7 calcined at different temperatures for 2 h143



frequencies. These compositions closely matched151,152

the shrinkage profiles with certain commercially avail-able LTCC systems, allowing the cofiring of systemswith two materials. Plugs made of the high er bismuthbased compounds were integrated into a low er LTCCmatrix and cofired to produce a miniaturised, highperforming 2?5 GHz micro strip band pass filter withexcellent characteristics. By utilising the 3D capabilitiesof LTCC technology, Baker et al.151,152 used a series ofloop inductors and parallel plate capacitors within astructure to create a unique miniaturised patch antennawith antenna size reduction up to 93% with good bandwidth and gain characteristics. Mixed dielectric struc-tures combine the attributes of high and low relativepermittivity materials. Low er substrates are useful forimpedance matching transmission lines and for mini-mising cross-talk. The incorporation of high er bismuthpyrochlore capacitors in low er LTCC substrates wasfound151,152 to decrease band pass filter dimensions withimprovement in the overall filter characteristics.

Kagata et al.30 also investigated the microwavedielectric properties of bismuth based compounds.They reported that BiNbO4 ceramics is difficult to sinterwithout additives. An addition of small amounts of CuOor V2O5, CuV2O6, B2O3 to BiAO4 (A5Nb/Ta) resultedin dense ceramics with er in the range 40–45 and Qf up to30 000 GHz and low tf when sintered at temperatures,950uC.30,153–162 Finally, Bi can be partially substitutedby La, Nd, Sm, Ce and Nb/Ta by Mo, Sb,etc.153,154,158,160

Tungsten bronze typeTungsten bronze type BaO–Ln2O3–TiO2 ceramics(Ln5Nd/Sm) sintered at y1400uC are well knownmicrowave compositions having moderately high rela-tive permittivity (70–100), high Qf (.7000 GHz) andzero tf. BaO–Ln2O3–TiO2 (Ln5Sm/Nd) in 1 : 1 : 4 or1 : 1 : 5 compositions are especially suitable for dielectricresonators in mobile phone hand sets.163 It has thusclear that these compositions have also been investigatedby several authors79,81,85,164–169 as a basic dielectric forLTCCs. Dernovsek et al.85 reported the effect ofaddition of B2O3–Bi2O3–SiO2–ZnO (BBSZ) andLa2O3–B2O3–TiO2 (LBT) modified by BaO, ZrO, SrOon the densification and microwave dielectric propertiesof BaNd2Ti4O12 ceramics. Especially the addition of10 vol.-%BBSZ enabled sintering at 900uC producing acomposition with er of 68, Qf above 6000 GHz and zerotf. Even higher Qf (8500 GHz) was achieved by Chenget al.168–170 with the addition of 42BaO–45B2O3–13SiO2

in Ba(Nd,Sm,Bi)2Ti5O14. Sintering performed aty900uC, however, decreased er to 40. In this research,it was also found that the wetting ability of the glass byrecalcining the glass–ceramic mixture improved themicrowave dielectric properties.168

The highest Qf values in tungsten bronze basedLTCCs was reported by Park et al.81 They reportedthe relative permittivity and Qf value of 32 and9000 GHz respectively, to the composition made ofMBRT-90 with 10 wt-% 52?45Li2O–31?06B2O3–11?99SiO2–2CaO–2?5Al2O3 and sintered at 875uC.However, these microwave ceramics also easily formedsecondary phases with glasses which were added todecrease the sintering temperature. The secondaryphases thus formed altered the relative permittiv-ity79,164,165 and the microstructure.

BaO–TiO2 systemBaO–TiO2 system is also widely used in microwaveapplications. The typical phases BaTi4O9 and Ba2Ti9O20

are commonly sintered at about 1250 and 1300uC, and er

and Qf are close to 36 and 50 000 GHz respectively.Additionally, the tf value depends on the formationof secondary phases, but can be very close to0 ppm K21.171 BaO–TiO2 with 0?1 wt-%WO3 (N-35)was found to show excellent microwave dielectricproperties with er535, Qf552 000 GHz and tf close to0 ppm K21.172 The sintered N-35 consists of BaTi4O9,Ba2Ti9O20 and BaWO4 phases. However, its sinteringtemperature is relatively high (1360uC). In order tolower the sintering temperature, Takada et al.105 added5ZnO–2B2O3, B2O3, SiO2 and six categories commercialglasses such as simple glass formers, ZnO–B2O3 based,B2O3–SiO2, Al2O3–SiO2, lead containing and alkalicontaining glasses. The commercial glasses have soft-ening points in the range 595–926uC. The addition of5 wt-% SiO2–B2O3 lowered sintering temperature toy1200uC, but the SiO2 glass considerably reduced thequality factor. All other glasses in 5 wt-% reduced thesintering temperature to y1100uC with a Qf factor inthe range 1000–13 000 GHz and er in the range 24–31.The dielectric properties of N-35 with different glassesare given in Table 7. Several groups173–175 studied theeffect of adding glasses, such as B2O3, Ba2Ti9O20,BaB2O4, etc., in Ba2Ti9O20. It was found173–175 thataddition of 5 wt-%B2O3 and sintered at 900uC gavesingle phase Ba2Ti9O20. However, the addition of largeramount of B2O3 led to the formation of BaTi(BO3)2 andrutile secondary phases. Choi et al.176 studied the effectof addition of lithium BSG (10–35 wt-%SiO2, 23–43 wt-%B2O3 and 33–51 wt-%Li2O) having the relative per-mittivity of 7?5 in BaTi4O9. The addition of 10 wt-%glass frit sintered at 900uC showed a density of 98% wither of 32, Qf of 9000 GHz and tf of 10 ppm K21. Secondphases of BaTi5O11 and Ba4Ti13O30 were observed whichdid not adversely affect the properties. The bestcomposition with BaTi4O9 was, however, reported byJhou and Jean.74 They increased BaO content in thebarium zinc borate (BZB) glass and for BZB glass with0–20 mol.-%BaO content in 90 vol.-%BaTi4O9z10 vol.-%BZB, the er varied in the range 28–33 and theQf varied in the range 15 000–20 000 GHz.

Zinc niobatesMNb2O6 (M5Ca, Co, Mn, Ni or Zn) ceramics areknown177,178 as a useful microwave dielectric materials.The ZnNb2O6 sintered at 1150uC for 2 h has Qf of83 700 GHz and er of 25.178 Kim et al.179 reported thataddition of 5 wt-%CuO to ZnNb2O6 decreased thesintering temperature to y900uC. The presence of aCuO rich intergranular phase, identified as(ZnCu2)Nb2O6, was observed indicating liquid phasesintering. Since this secondary phase has a low meltingpoint with excellent dielectric properties (er516?7,Qf541 000 GHz and tf5276 ppm K21), the finalcomposition was able to reach er of 22?1, Qf of59 500 GHz and tf of 266 ppm K21. It was alsofound180,181 that addition or substitution of V2O5 toZnNb2O6 lowers the sintering temperature to y900uC,but with a lossy secondary phase degrading the qualityfactor. On the other hand, the Zn(Nb0?942V0?06)2O6

samples sintered at 875uC for 2 h showed a single phase



columbite structure with er of 23?9, Qf of 65 000 GHzand tf of 272?8 ppm K21. This composition, as alsoZn(Nb.95V.025)O5?85 sintered at 1100uC with er of 23?8,Qf of 64 000 GHz and tf of 250 ppm K21, waschemical compatible with silver.181 In these composi-tions, the large negative tf is caused by the ZnNb2O6

having the value of 256 ppm K21.177,178 Kim et al.182,183

added TiO2 and showed that (12x)ZnNb2O62xTiO2

with x50?58 has a zero tf with er of 45 and Qf of30 000 GHz. The sintering temperature of this composi-tion was relatively high, and addition of CuO loweredthe sintering temperature but formed secondary phasesdecreasing the Qf. The (12x)ZnNb2O6–xTiO2 (x50?58)with 10 wt-%CuO sintered at 875uC showed Qf of17 000 GHz, er of 37 and tf of 27 ppm K21.183

The Zn3Nb2O8 has also been reported to be a materialwith excellent dielectric properties but high sinteringtemperature of y1200uC. Several different sintering aidshave been tried to lower the sintering temperature.184–186

An addition of 2 mol.-%V2O5 and sintering at 850uC for4 h produced er of 22?4 with Qf of 67 500 GHz.185

The BaNb2O6 exists in two polymorphic forms beinghexagonal at low temperatures and transforms toorthorhombic at y1150uC.187 The transition is rever-sible and the dielectric properties of both the phases arevery different. The hexagonal phase prepared bysintering at 1050uC has er of 42, Qf of 4000 GHz andtf of 2800 ppm K21, but orthorhombic phase sinteredat 1300uC shows er of 30 with Qf of 43 000 GHz and tf

of 245 ppm K21. Sreemoolanathan et al.188,189 reportedthat Ba5Nb4O15 is a suitable material for microwaveapplications but its sintering temperature (1400uC) andtf are quite high. Kim et al.349 found that B2O3 additionto BaNb4O15 lowers the sintering temperature toy925uC by producing the hexagonal BaNb2O6 havinga high negative tf which compensated for the highpositive tf of Ba5Nb4O15. Addition of 3 wt-%B2O3 toBa5Nb4O15 resulted in the formation of 6?3 vol.-%BaNb2O6. For this composition, er was 39 and Qfwas 18 700 GHz with zero tf. Figure 9 shows thevariation of dielectric properties as a function of B2O3

content. Kim et al.190,191 further developed the composi-tion by adding both B2O3 and V2O5. When a mixture of0?3 wt-%B2O3 and 0?3 wt-%V2O5 was added, thesintering temperature decreased to 900uC/2 h. It wasalso found that 0?063 vol.-% hexagonal BaNb2O6

formed could tune the tf to 0 with er of 42 and Qf of19 500 GHz.

(Mg,Ca)TiO3

(Mg,Ca)TiO3 is a very useful dielectric material for highfrequency antenna applications. When sintered at,1350uC, er is y20, Qf is 86 000 GHz and tf is23 ppm K21.192 In order to decrease the sinteringtemperature, Chen et al.71,193 studied the densifica-tion and microwave dielectric properties of(Mg0?95Ca0?05)TiO3 with barium borosilicate basedglass. With the volume ratio of 50 : 50, the compositeexhibited the highest er and quality factor. However, theXRD and SEM studies indicated chemical reaction ofthe ceramic and glass with formation of secondary phaseof BaTi(BO3)2. Additionally, the glass–ceramic compo-site was found to be very porous showing also very lowshrinkage characteristics.

Several additives enabling liquid phase sintering ofMgTiO3 have also been investigated.194,195 These

additives, such as Bi2O32V2O5, commonly producedsecondary phases decreasing the er. Decomposition ofthe MgTiO3 to MgTi2O5 and Mg2TiO4 during liquidphase sintering using lithium borosilicate glass was alsoobserved.195 However, this decomposition does notadversely affect the dielectric properties since MgTi2O5

has er517?4 and Qf 547 000 GHz and Mg2TiO4 haser514?4 and Qf555000 GHz. Jantunen et al.196–199

made a detailed study of the effects of different glasscompositions on the tape casting and the microwavedielectric properties. Nearly full density (97%) wasachieved when ZSB glass (60?3ZnO–27?1SiO2–12?6B2O3) was mixed with the (Mg,Ca)TiO3. Afterfiring fully crystalline structure with ZnTiO3, Zn2SiO4,Mg4/3Zn2/3B2O5 and TiO2 phases were found. Withoptimised composition, the material system sintered at900uC showed excellent microwave properties such aser58?5–9?5 and dielectric loss of ,0?001 at 7 GHz.Jantunen et al.196 prepared this composition also with-out adding separate glass phase. The ceramic powderwith 70 wt-% glass composed of oxides ZnO, SiO2 andB2O3 in 60?3 : 12?6 : 27?1 mol.-% was mixed in a ball mill,dried, pressed and sintered at 900uC. The samplesprepared in this method were found to have betterproperties than those prepared by mixing glass withceramic powder. This kind of glass addition to decreasethe sintering temperature of the (Zr,Ca)TiO3 was alsoreported by Choi et al.200 The addition of lithiumborosilicate glass to CaZrO32CaTiO3 system loweredsintering temperature from 1450 to 900uC.

a quality factor; b relative permittivity; c temperaturecoefficient of resonant frequency

9 Microwave dielectric properties of Ba5Nb4O15 ceramics

sintered at 925uC for 2 h as function of amount of

B2O3 added349



(Zr,Sn)TiO4 system(Zr,Sn)TiO4 having excellent high frequency properties(er540, Qf553 000 GHz and tf50 ppm K21) has beenused for microwave applications for decades201 and thusseveral groups202–208 have worked on decreasing itssintering temperature from 1600uC. Takada et al.202

investigated the effect of addition of several commercialand non-commercial glasses (such as SiO2, B2O3,5ZnO22B2O3, ZnO2B2O32SiO22Li2O2CuO) andsintering aids (ZnO, CuO, V2O5, La2O3, BaO andBi2O3 with various combinations).The preparation ofdense (Zr,Sn)TiO4 seems to be difficult when sintered attemperatures less than 1200uC. Wang et al.207 succeededin sintering the (Zr,Sn)TiO4 at 1050uC for 4 h usingBaO2B2O3–SiO2–Li2O–CuO glass. With 10 wt-% glassaddition, er530, Qf530 300 GHz and tf524 ppm K21.However, this glass was not effective in densifying theceramic and the samples had relatively low density.

Systems with originally low sinteringtemperatureMost tellurium based oxide materials can be synthesisedand sintered at temperatures below 900uC, representinga potential candidate for use in LTCC technology withlow sintering temperatures. For ceramic processing, themost important oxidation states of Te are Te4z andTe6z, where Te4z has a lone electron pair. Pure TeO2

never oxidises in air to form 6z oxidation state.209

Udovic et al.210 reported that TeO2 has a poorsinterability and the ceramics sintered at 640uC for15 h has 20% porosity with er519?3, Qf530 000 GHzand tf52119 ppm K21.

Many authors210–212 have reported the synthesis ofTiTe3O8 with a cubic unit cell from oxides at 700uC.Kwon et al.213 reported that it is difficult to prepare itsdense ceramic. Udovic et al.210 prepared single phasedense TiTe3O8 by muffling in TeO2 powder and thesamples showed er of 50 and Qf of 30 600 GHz, but thetf was z133 ppm K21. Figure 10 shows a typical TEMimage of a TiTe3O8 ceramic sintered at 720uC for 5 h.The low porosity led to considerable improvement inproperties as compared to Maeda et al.177 In order tolower tf, they prepared TiTe3O8–TeO2. The resultsshowed that TiTe3O8 and TeO2 have negligible solid

solubility when sintered into a dense ceramic at 670uC.Figure 11 shows the variation of the microwavedielectric properties of TiTe3O8 as a function of TeO2

content having a zero tf with er of 30 and Qf of22 000 GHz for the composition 0?15TiTe3O82

0?85TeO2. Valant and Suvorov214 reported thatCaTeO3 and CaTe2O5 sintered well at low temperatures(,900uC) with excellent quality factor but the reactionwith silver forms a problem. Kwon et al. reported215

BaTe4O9 as a high Q LTCC material with a densemicrostructure when sintered at 550uC showing er of17?5, Qf of 54 700 GHz and tf of 290 ppm K21.Figure 12 shows the microstructure of this ceramicsintered at 550uC. However, BaTe4O9 was found to bechemically compatible and successfully cofired withaluminium electrode maintaining good electrical proper-ties. Figure 13 shows the cross-sectional scanningelectron micrographs of cofired BaTe4O9 with Al topelectrode and integrated and cofired BaTe4O9/Al innerelectrode/BaTe4O9 sample. Udovic et al.216 preparedseveral bismuth tellurite compounds such as Bi2Te2O8,Bi2TeO6, Bi6Te2O15 and 7Bi2O322TeO2 in oxygenatmospheres with low sintering temperatures down to650uC. The compositions had er in the range 33–56 andQf up to 41 000 GHz with negative tf. However,Bi2Te2O8 and Bi2TeO6 compounds are found to reactwith silver, whereas no reactions with bismuth richcompositions such as Bi6Te2O15 and 7Bi2O322TeO2

were observed. Figure 14 shows the microstructure ofBi6Te2O15 sintered at 800uC for 10 h. Valant andSuvorov217 investigated Bi12MO202d (M5Si, Ge, Ti,Pb, Mn or B1/2P1/2) sillenite compounds. The ceramicscan be sintered at a relatively low temperature ofy800uC. These compositions had er in the range 37–41,Qf up to 8000 GHz, and all have negative tf.Additionally, the Bi12MO202d ceramics do not seem toreact with silver being thus suitable materials for LTCCapplications.

The ZnO–TiO2 system contains ZnTiO3 (hexagonal),Zn2TiO4 (cubic) and Zn2Ti3O8 (cubic).218 The prepara-tion of ZnTiO3 from a mixture of ZnO and TiO2 isdifficult because the compound decomposes into

10 Typical TEM image of TiTe3O8 ceramic sintered at

720uC for 5 h and cooled at 100 K min21: micrograph

reveals no main structural defects21011 Microwave dielectric properties of composition from

TiTe3O8–TeO2 tie line210



Zn2TiO4 and rutile at y945uC.219 Haga et al.220 in 1992reported for the first time the microwave dielectricproperties of ZnO–TiO2 ceramics. Later in 1998Golovochanski et al.221 reported that ZnTiO3 can besintered at a relatively low temperature of y1100uCwith Qf530 000 GHz and er519 and proposed it as asuitable material for LTCC. ZnTiO3 has a negative tf

and addition of rutile improves the tf close to 0.222,223

Several authors222–224 studied the effect of glass additionon the sinterability and microwave dielectric propertiesof ZnTiO3 ceramics. Addition of B2O3, ZnO–B2O3,B2O3zLiF, etc., all lowered the sintering temperaturewith reasonably good dielectric properties. Figure 15

shows the variation of microwave dielectric properties ofZnTiO3z0?25TiO2 with B2O3 content sintered at 875uCfor 4 h.222 The best properties, er530, Qf556 000 GHzand tf510 ppm K21, were obtained with 1 wt-% addi-tion of B2O3 sintered at 875uC for 4 h.222 Also theaddition of 2 wt-%ZBS lowered sintering temperature to

12 Image (SEM) of BaTe4O9 ceramic sintered at 550uCfor 2 h215

13 Cross-sectional SEM image of a cofired BaTe4O9 with

Al top electrode and b cofired BaTe4O9/Al inner elec-

trode/BaTe4O9 sample215

14 Image (SEM) of thermally etched microstructure of

Bi4Te2O15 ceramic fired at 800uC for 10 h216

15 Microwave dielectric properties of ZnTiO3z0?25TiO2

mixture as function of B2O3 content sintered at 875uCfor 4 h222



900uC for 3 h with good dielectric properties of er527,Qf520 000 and tf52 ppm K21.223 Furthermore, it wasfound that this composition does not react with silver,and thus Zhang et al. proposed it as an ideal material forLTCC applications.223 Further improvement of themicrowave properties of hexagonal ZnTiO3 has beenpreformed by replacing it partly by hexagonalMgTiO3.225–227 Thus the thermal stability and unitcell parameters of the hexagonal phase varied withMg content of the system.225 Zero tf can be obtainedin Zn12xMgxTiO3 for x in the range 0–0?1 whensintered at y925uC.227 X-ray diffraction and thermalanalysis showed that the stability range of thehexagonal phase increased to higher temperatures asthe Mg content increased. Sintering (Zn,Mg)TiO3

above 950uC led to the formation of (Zn,Mg)2TiO4

and rutile, the latter one enabling material with zerotf. Finally, Lee and Lee227 studied the effect of addi-tion of zinc borate (3ZnO–B2O3) to Zn0?95Mg0?05TiO3z0?25TiO2 in the temperature range 860–940uC. Thezinc–borate addition of y1 wt-% significantly improvedthe density and microwave dielectric properties and at900uC excellent microwave properties were achieved(er523?6, Qf530 990 GHz and tf528 ppm K21).

Ca(Li1/3Nb2/3)O32d represents also a composition thathas low intrinsic sintering temperature (1150uC). Kim etal.228 reported that this complex perovskite is also auseful low loss dielectric material, but it needs to besintered in a Pt box to control the volatility of Li2O atsuch high temperatures. Hence the decrease in itssintering temperature is needed in two ways and severalauthors229–234 have added glasses to Ca(Li1/3Nb/Ta2/

3)O32d. The 4 wt-% addition of B2O3 significantlyimproved the density of non-stoichiometric Ca(Li1/

3Nb2/3)O32d or Ca(Li1/3Ta2/3)O32d229,230 with as good

dielectric properties sintered at 990uC as at 1150uC(er530?6, Qf531 000 GHz and tf5217?5 ppm K21).However, addition of larger than 4 wt-% of B2O3

deteriorated the dielectric properties due to formationof Li2B4O7. In order to lower tf, also in this caseTi was partially substituted233,235,236 for Li–Nb. Liuet al.232 studied the effect of B2O3 addition inCa[(Li1/3Nb2/3)12xTix]O32d (x50–0?2). An orthorhom-bic single phase is formed in the entire range of the

composition (x50–0?2). As x increased from 0 to 0?2, er

increased from 30 to 89, Qf decreased from 33 000 to3820 GHz and tf increased from 216 to 22?4 ppm K21.For x50?1 and sintered at 940uC with 1 wt-%B2O3

showed er of 50, Qf of 6500 GHz and tf of27?6 ppm K21.232 However, an addition of a glass fritgave better dielectric properties.234 With a glass fritaddition level of z12 wt-% samples sintered at 900uCfor 3 h, the er, Qf and tf were 40, 12 500 GHz and28 ppm K21 respectively.234 Ha et al.233 investigatedthe effect of Bi2O3 addition on lowering sinteringtemperature, densification and dielectric properties inCa[(Li1/3Nb2/3)12xTix]O32d. Ca[(Li1/3Nb2/3)0?8Ti0?2]O32d

with 5 wt-%Bi2O3 addition sintered at 900uC had er535,Qf511 000 GHz and tf513 ppm K21.236 Figures 16–18show the variation of er, Qf and tf as a function of Tiand Bi2O3 contents.

An interesting basic ceramic for LTCCs is also(Ca12xNd2x/3)TiO3 having er580–100 and Qf5150–1000 GHz when sintered at 1300uC.237 Figure 19shows the XRD pattern of (Ca12xNdx)TiO3 ceramicsfor different values of x. In order to lower thesintering temperature and to improve densification,Wei and Jean238 added 3ZnO22B2O3 glass to thiscomposition. The addition of 20 vol.-% or more ofthe glass lowered sintering temperature to 850–900uC,and reactions took place at the interface betweenthe glass and the dielectric ceramics. The Ca in(Ca12xNd2x/3)TiO3 dissolved into the glass formingthe glass of CaO–ZnO–B2O3 at 870–880uC whichimproved the densification of the ceramic. The samplewith 20–40 vol.-% glass sintered at 900uC shows er in therange 30–60, Qf of 2000–5000 GHz and tf of 20–60 ppm K21. However, improved dielectric propertieswere reported by Kim et al.236 with the addition of ZnO–H2BO3 from 1 to 4 wt-% in Ca0?6(Li0?5Nd0?5)0?4)0?45Zn0?55TiO3.The Ca0?6(Li0?5Nd0?5)0?4)0?45Zn0?55TiO3 with the2 wt-% addition of 0?33ZnO–0?67H3BO3 sintered at875uC for 4 h had er of 42, Qf of 10 300 GHz and tf of19?5.

16 Relative permittivity of Ca[(Li1/3Nb2/3)12xTix]O32d spe-

cimen sintered at 900uC for 3 h as function of TiO2

and Bi2O3 content in starting mixture234

17 Qf of Ca[(Li1/3Nb2/3)12xTix]O32d specimen sintered at

900uC for 3 h as function of TiO2 and Bi2O3 content

in starting mixture234



Material systems with originally high Q value orhigh er

Yokoi et al.239 reported that Mg4Nb2O9 sintered with3 wt-%LiF at 850uC has a very high quality factor of103 600 GHz with er of 12?6. Kan et al.240 reported thata small amount of V substitution for Nb in Mg4Nb2O9

improved the quality factor and decreased the sinteringtemperature. However, the tf was relatively high(270 ppm K21) for practical applications. In order tolower the tf, Yoki et al.241 added 6 wt-%CaTiO3 sinteredat 950uC for 10 h to get er of 15?7, Qf of 22 100 GHzand tf of 23?3 ppm K21.

The AgNbO3 and AgTaO3 compounds represent aclass of materials with high relative permittivity greaterthan 400 with Qf in the range 600–900 GHz.242–244 Ingeneral, these compounds undergo a series of structuralphase transitions as they cool from the prototypiccubic perovskite phase and AgNbO3 exhibits aweak ferroelectric behaviour at room temperature.245

One example is a composite structure consisting of45 wt-%Ag(Nb0?65Ta0?35)O3 and 55 wt-%Ag(Nb0?35Ta0?65)O3

having er of 430 and Qf of 700 GHz. Large grain sizehelps to minimise the reaction between phases duringsintering.244 Moreover, the evaporation and reductionof Ag2O at high temperature and in oxygen deficientatmospheres severely affect the densification and micro-wave propertie.244 In order to lower the sinteringtemperature Sakabe et al.246 added V2O5 and substitutedLi for silver in Ag(NbxTa12x)O3. More recently, Kimet al.247 succeeded in lowering the sintering temperatureto below 950uC by liquid phase sintering with theaddition of 1 wt-%CuO. They adjusted the temperaturecoefficient of capacitance by adjusting the Nb/Ta ratioin the solid solution and by creating composite micro-structures.247 This CuO added temperature stablecomposite had a relative permittivity of y390 and Qfof y800 GHz. Scanning electron microscopy andEDAX analysis revealed that CuO segregated at thegrain boundaries. Figure 20 shows the variation of

temperature coefficient of capacitance for Ag(Nb,Ta)O3

end members and composite. The ANT31:13 sintered at900uC for 2 h is nearly temperature stable. Additionallyit was found that the material did not react with silverconductor and thus is a promising candidate asembedded capacitors for high frequency applications.247

Other LTCC systemsBorisevich and Davies reported248–250 thatLi1zx2yM12x23yTixz4yO3 (M5Nb/Ta; x50?1;y50?05–0?175) solid solutions are potential candidatematerials for LTCC applications with a quality factor up

19 X-ray diffraction spectra of (Ca12xNd2x/3)TiO3

ceramics237

18 tt of Ca[(Li1/3Nb2/3)12xTix]O32d specimen sintered at

900uC for 3 h as function of TiO2 and Bi2O3 content

in starting mixture234

20 Temperature dependence of relative permittivity for

ANT31:13 end members and composite247



to 10 500 GHz when sintered at 1100uC. However,volatile Li has a deleterious effect on dielectric proper-ties in Li based ceramics and the deficiency of Li lead todecrease in density and lattice defects. Nevertheless,several groups have reported LTCC compositions basedon the Li2O–M2O5–TiO2 system.251–254 Commonly thelower sintering temperature was achieved by additionof oxides or their combinations, such as Li2O, V2O5

and B2O3. The relative permittivity values were inthe range of 20 up to ,65, the Qf value even up to50 000 GHz. One practical example is 5Li2O2

0?583Nb2O523?248TiO2z1 wt-%V2O5 sintered at920uC with good dielectric properties (er521?5,Qf533 000 GHz and tf56?1 ppm K21).254

Mori et al.255,256 studied MgAl2O42Li2Mg2Zn2

B2Si2O glass. The glass–ceramic sintered at 900uCshowed er of 7?4 with high Qf of 48 000 GHz and tf of290 ppm K21. The mechanical strength and thermalconductivity were 250 MPa and 5?59 W m21 K21

respectively. Although the composite has excellentquality factor, the temperature stability is poor whichprevents its immediate application. However, recentlySurendran and Sebastian257 have reported that it ispossible to tune tf by the addition of TiO2.

Kato et al.258 reported the microwave dielectricproperties of (Pb,Ca)(Fe1/2Nb1/2)O3 ceramic andKucheiko et al.259 improved its microwave propertiesby partial substitution of Fe and Nb to er of ,94, Qf of7100 GHz and tf of z18 ppm K21 typically sintered at1150uC. These compositions indicate the possibility ofproducing LTCCs with relative permittivity close to 100.Very complicated materials systems, however, easilyform. Additionally, the LTCC compositions basedon (Pb,Ca)(Fe1/2Nb1/2)O3 can be adjusted, e.g. to beparaelectric at room temperature260 and compositionswith the relative permittivity from 40 to ,130 havebeen reported.235,259–266 One interesting example is(Pb,Ca,La)(Fe,Nb)O3 with 1 wt-% addition ofPbO2B2O32V2O5 glass studied by Yang et al.235

When sintered at 1050uC, only slight degradation ofthe properties was observed although Pb6BVO10 wasdetected as a secondary phase. The dielectric pro-perties measured were er5101, Qf55400 GHz andtf55?9 ppm K21.

The Mg3(VO4)2 ceramic has an orthorhombic struc-ture with space group Cmca.267 The Mg3(VO4)2

ceramics sintered at 1050uC showed the high Qf of64 000 GHz, with er59?1 and tf5293 ppm K21.268,269

They could also achieve the same properties by sinteringthe sample at 950uC by increasing the sintering durationto 50 h. The XRD studies also showed that the ceramicsdo not react with silver. The Mg3(VO4)2 decompose aty1074uC to form a liquid phase.270 In order to lowerthe sintering temperature, Mg was substituted268 par-tially by Co by forming Mg32xCox(VO4)2 enabling thedecrease in the sintering temperature from 1050 to850uC due to formation of CoO–V2O5 liquid phase. TheMg32xCox(VO4)2 with x52 sintered at 900uC for 5 hshowed Qf of 78 000 GHz and er59?4 andtf5295 ppm K21. The vanadate system, Ba3(VO4)2

ceramic with a high sintering temperature of 1600uC/5 h has also been studied having er of 11, Qf of62 350 GHz and tf of 28?8 ppm K21.269 The additionof 0?5 wt-%B2O3 resulted in a Qf of 41 000 GHz, er of12?5 and tf538?8 ppm K21 when sintered at 950uC for

5 h, but larger addition of B2O3 led to a formation of thesecondary phase Ba2V2O7 and degraded dielectricproperties.

Complex perovskite Ba(Mg1/3Nb2/3)O3 ceramic hasgood microwave dielectric properties with er of 32,Qf556 000 GHz and tf of 33 ppm K21.271

Kolodiazhnyi et al.272 reported that the Qf of thisdielectric considerably improved reaching 160 000 GHzwhen prepared by solid state method using MgNb2O6

precursor. However, its sintering temperature isy1450uC. Lim et al. have studied this composition asa basic ceramic for LTCCs and reached as low sinteringtemperature as 875uC273,274 with addition of 2 mol.-%B2O3 and 10 mol.-%CuO. The ceramic had a Qf valueof 21 500 GHz with er of 31 and tf of 21?3 ppm K21.

Bian et al.275 reported that AMP2O7 (A5Ca/Sr,M5Zn/Cu) ceramics are suitable glass free LTCCmaterials. Some of them can be sintered at temperaturesof y900uC with a low er of y7, Qf up to 10 000 GHzand negative tf of about 270 ppm K21. Some modifica-tions to improve the tf value or enhance the densificationhave been proposed especially by Kim et al.276 However,it must be kept in mind that these materials all react withsilver.

Constrained sinteringLike all ceramic materials, the LTCC tapes shrink in allthree directions during a free sintering process being 12–16% in the X–Y (radian) direction and slightly more inthe thickness (axial) direction. The shrinkage andshrinkage variation limit the size of the substrates thatcan be processed, impose limitations on embeddedpassive components, and introduce complexity in theprocessing of boards with cavities. The constrainedsintering technology was consequently proposed as asolution, referring to various techniques used in LTCC:pressure assisted sintering (PAS), pressureless assistedsintering (PLAS), self-constrained sintering and theLTCC-M approach. In the LTCC-M, a metal substrateis used as a constraint.277–280 Except for the PAStechnique, all use either an internal or external non-sintering material to constrain in plane shrinkage of theLTCC, to achieve zero shrinkage in the X–Y direction.This controlled shrinkage makes the printed metallisedfeatures unchanged and enables the formation of precisecavities. An external pressure is required to makecontact between non-shrinking Al2O3 layers andLTCC tapes. Hot pressing is used for pressure assistedconstrained sintering to manufacture multilayer ceramicsubstrates. Zuo et al.281 reported X–Y shrinkage freesintering of LTCC cylindrical samples by in situadjusting of the applied uniaxial compressive stressesbased on concurrent radial strain measurements. Theconcept of constrained sintering or zero shrinkagetechnology has recently become important in LTCCfor the precise control and maintenance of sinteringshrinkage and tight dimensional tolerances.277–280

During the normal cofiring, stresses develop because ofthe mismatch in sintering behaviour of differentcomponents.18,282–284 These stresses can lead to warpand non-uniform shrinkage leading to dimensionalvariations. The zero shrinkage technology is thus anattractive option as it completely inhibits the transverseshrinkage, resulting in extremely low dimensional



changes in the plane of the structure, thus maintainingtight tolerances.

Rabe et al.285 reported production of LTCC moduleswith shrinkage in X–Y direction of less than 0?5% bothby self-constrained tapes and by self-constrained lami-nates. Self-constrained tapes are based on the integra-tion of a layer preventing shrinkage inside each tape.The self-constrained laminates consist of special tapessintering at different temperature intervals.285 Kagataet al.100 succeeded in making non-shrinkage LTCC byfiring the laminated sheet with HTCC alumina ormagnesia green sheets on both sides and then removingthe non-sintered HTCC. The glass–ceramic sheet shrinksonly in the Z direction and not in the X–Y direction dueto the constraining effects of the HTCC layers.

Choi et al.80 reported that low er LTCC layers forroutine function and the middle er LTCC layers forresonators are to be incorporated in the module torealise multifunctional LTCC module. When low er andmiddle er LTCC tapes are laminated and cosintered inthe module, the physical and chemical incompatibilitiesbetween the hetero layers can lead to severe problemssuch as delamination and warping. Delamination mayoccur when there is a large difference between theshrinkage behaviour of thermal expansion of the heterolayers and also when there are chemical reactionsbetween the glass frits of the low er and middle er layers.Densification profile mismatch can also lead to warping.Although several reports were published on the devel-opment of low er and middle er materials, very fewattempts were made on the cofiring of low er and middleer LTCC materials. Choi et al.80 made a very detailedstudy of matching the low er and middle er LTCCcompositions physically and chemically in the cosinter-ing process. They selected ZnNb2O6–TiO2 (er 5y20)ceramics as middle er ceramics. Glasses with alumina asa filler was used as the low er (er5y6) material. Severalglass compositions were tried and modified for matchingthe shrinkage of the low er and middle er layers. Bycontrolling the processing parameters such as the solidloading ratio and stacking sequence, the warping of themodule could be minimised.282 It is found that thedelamination and warping occur when the low er and

middle er materials have different glass frits as shown inFig. 21a. When there are differences in the shrinkageprofile parameters, warping occurs as shown in Fig. 21b.However, when the same glass frit was used for both lower (LG3: 55 wt-%Al2O3z45 wt-% glass frit AE-alumi-noborosilicate) and middle er (MG4: 80 wt-%ZnNb2O6–TiO2z20 wt-% AE-alumnoborosilicate glass frit), aminimum delamination occurred (Fig. 21c). Thus bycontrolling the processing parameters such as the solidloading ratio, sintering profile and the stackingsequence, the warping between the hetero layers can beminimised as shown in Fig. 22.

ConclusionsThere are about 400 low loss dielectric materials(Table 7) reported with sintering temperature less than1100uC. Figures 23 and 24 show the variation of their Qfand tf as a function relative permittivity respectively. Ingeneral, as with all dielectric materials, the dielectric lossincreases with increasing er. Within the low relativepermittivity materials (,20), there are several tempera-ture compensated compositions such as ZnO–B2O3–SiO2 (60 : 20 : 20) glass and NaAlSi2O8 and severalothers needing only a slight adjustment fulfillingthis demand. Some of these materials such asKxBa12xGa22xGe2zxO8, BaGa2Ge2O8, SrCuP2O7,Mg4(Nb22xVx)O9 (x50?0625), Mg4NbTaO9,Mg4Nb1?5Ta.5O9 and Mg4Nb2O9z3 wt-%LiF, havealso high Qf .100 000 GHz. The Mg4NbTaO9 sinteredat 1100uC showed the highest quality factor (Qf5,280 000 GHz) with er of 11?8 and tf of266 ppm K21. There is, however, some further researchto be performed with these low relative permittivitymaterials. First, suitability for LTCC applications ofmany of these compositions is not examined and second,any of these is not able to reach the high Qf values680 000 GHz of Al2O3.286 Finally, further lowering ofthe sintering temperature of some of these compositionsshould be carried out which could be obtained byaddition of suitable glasses, or low melting additivessuch as CuO, V2O5, Bi2O3, etc.

Within the high relative permittivity materials (.70),the situation is better. The properties of reported LTCC

21 a, b cofiring of low and middle relative permittivity LTCC tapes with delaminastion and warpage, and c cofiring of

tapes with matched shrinkage profiles (LG3 and MG4): optical microscopy images with sintering at selected

temperature80



compositions (Table 7) well compete with the dielectricmaterials needing sintering temperature near 1500uC.The most successful ones are the compositions where

low sintering temperature has been reached by theaddition of a very small amount of sintering aid such asBi2O3–TiO2 (1 : 11?3) with 0?112 wt-%CuO and TiO2

with 2 wt-%CuO, with reported sintering temperaturesclose to 900uC. Their permittivity and Qf values are 81and 6085 GHz, and 98 and 14 000 GHz respectively. Ifcompared with the well known high relative permittivitycompositions, Ba–Nd–(Bi)–Ti oxides with sinteringtemperature between 1350 and 1500uC, having therelative permittivity and Qf values typically close to 90and 8300 GHz,287–289 the work with correspondingLTCC compositions has been very successful. Thesematerials have also been well temperature compensated.

Although several authors reported success in reducingthe sintering temperature to the level suitable for LTCC,very little attention was paid to know their chemicalcompatibility with electrode materials and silicon,thermal expansion, shrinkage, thermal conductivity,etc. Tapes of most of the materials are not made andtheir sintering behaviour, shrinkage, dielectric propertiesand chemical compatibility with electrode materials arenot investigated.

While there is no doubt that LTCC technology offersmany benefits over other packaging technologies, thereare three characteristics that are perceived as a limitationof this technology: shrinkage control, strength andthermal conductivity. While these are valid concerns,industry has addressed these issues by improvedmaterials, fabrication process and thermal via/heat sinktechnology as discussed below.

Fabricating large multilayer structures which incor-porate fine lines and spaces can result in alignmentproblems in the X and Y axis due to the shrinkagetolerance of ¡0?2%. This can lead to the problem of finepitch connector pads that traverse across the width ofthe substrate not aligning with the substrate. However,tape manufacturers have addressed the shrinkage issueby improving their tape casting processes. To avoidshrinkage, some manufacturers used tape on substratetechnology (TOS). Shrinkage is virtually eliminated bylaminating and firing each layer of tape on a substratemade of alumina, BeO or AlN. However, this process israther expensive. Some manufacturers such as CMAC-Thomson and Ragan have developed a zero shrinkLTCC tape system.

22 a total sintering shrinkage of ceramic green tapes by

adjusting solid loading ratio of LG3 and MG4 slurries,

b cofiring of LG3 and MG4 shown with optical micro-

scopy and SEM images of interface A–B bilayer struc-

tures and interface of c AB–A sandwiched structure80

23 Temperature dependence of relative permittivity of

dielectric LTCCs as function of relative permittivity

24 Quality factor of dielectric LTCCs as function of rela-

tive permittivity



While LTCC is known for its good electrical proper-ties, mechanical strength has been identified as one of itsmain weaknesses (150–150 MPa) as compared toalumina (400–500 MPa). Recently EMCA T8800 tapesystems showed mechanical strength comparable toalumina.

As the power density of MCMs continues to increase,thermal conductivity of the package must be able toconduct and spread the heat to maintain the productreliability. The LTCC ceramics have thermal conductiv-ity in the range 2?0–2?5 W m21 K21 and this low valueis a limitation in MCM designs. Many thermal manage-ment techniques are being utilised to improve thethermal conductivity through the substrate (Z axis) aswell as spreading the heat across the area of thesubstrate (X and Y axis). The most common methodof spreading heat is by applying a thick layer of gold orsilver on the back side. For applications requiring betterheat spreading, some manufacturers are looking atapplying a higher conductivity thin internal layer ormounting the substrate on higher conductive materialssuch as copper–tungsten (CuW) or copper–molybde-num–copper (CuMoCu). However, use of the additionalheat spreaders increases the weight of the modules.

Jang290 investigated the effect of pores existing at theconductor/dielectric interface and inside the conductorline on the microwave properties of LTCC packageswith experiments and simulations. Simulation resultsshowed that the pores existing at the interface made theQ value increase by 7–8% while eeff decrease by morethan 10%. The pores inside the conductor line madeconductivity of the conductor line and Q decrease.

As a final conclusion, it should be however noted thatthe research of novel LTCC compositions have beenvery successful showing outstanding improvement of thematerials properties. Especially, the high relative per-mittivity material offers an opportunity to furtherminiaturise the microwave modules and the low relativepermittivity, although not reaching yet the high Qfvalues of the best high sintering temperature dielectric,show a decrease in loss in large extent when compared tothe properties of commercially available LTCCs.

Acknowledgements

One of the authors (M. T. Sebastian) is grateful toNokia Foundation for the award of a Nokia VisitingFellowship to carry out research at University of Ouluand additionally, H. Jantunen acknowledges theAcademy of Finland for its support (projectno. 206123).

References1. L. Hongwei, H. L. Barnes, J. Laskar and D. Estrich: IEEE Trans.

Microwave Theory Tech., 2000, 48, 2644–2651.

2. T. A. Midford, J. J. Wooldridge and R. L. Sturdivant: IEEE

Trans. Antennas Propag., 1995, 43, 983–991.

3. R. R. Tummala Rao: J. Am. Ceram. Soc., 1991, 74, 895–908.

4. A. L. Eustice, S. J. Horowitz, J. J. Stewart, A. R. Travis and H. T.

Sawhillm: Proc. 36th Electron. Compon. Conf., Seattle, WA,

USA, May 1986, IEEE, 37–47.

5. J. Muller, H. Thust and K. H. Drue: Int. J. Microcircuits Electron.

Packag., 1995, 18, 200–206.

6. M. A. Rodriguez, P. Yang, P. Kotula and D. Dimos: J.

Electroceram., 2000, 5, 217–223.

7. H. T. Sawhil: Ceram. Trans., 1987, 26, 307–319.

8. K. W. Long and K. M. Luk: IEEE Trans. Antenna Propag., 1995,

43, 517–519.

9. K. Delaney, J. Barret, J. Barton and R. Doyle: IEEE Trans. Adv.

Packag., 1999, 22, 68–77.

10. R. Ludwig and P. Bretchko: ‘RF circuit design: theory and

applications’, 65; 2000, Upper Saddle River, NJ, Prentice Hall.

11. Y. Imanaka: ‘Multilayers low temperature cofired ceramics

(LTCC) technology’, Chapter 2; 2005, New York, Springer.

12. R. E. Mistler and E. R. Twiname: ‘Tape casting, theory and

practice’; 2000, Westerville, OH, The American Ceramic Society.

13. S. Dzuirdzia, S. Nowack, M. Ciez and W. Gregorcyzk: Proc. 26th

Int. Conf. on ‘International microelectronics and packaging

society – Poland Chapter’, Warshaw, Poland, September 2002,

IMAPS, 409.

14. J. Hagberg, M. Pudas, M. Kittila and S. Leppavuori: Proc. Int.

Symp. on ’Microelectronics’, Baltimore, MD, USA, October

2001, IMAPS, 681–687.

15. H. Jantunen, T. Kangasvieri, J. Vahakangas and S. Leppavuori:

J. Eur. Ceram. Soc., 2003, 23, 2541–2548.

16. H. Thust, K. H. Drue, J. Mueller, T. Thelemann, T. Tuschiek,

J. Chilo, C. Golovanov and F. Ndagijimana: Microwave J.,

1998, 41, 70–79.

17. W. Li and J. Lannutti: IEEE Trans. Compon. Packag. Technol.,

2005, 28, 149–156.

18. J.-H. Jean and C.-R. Chang: J. Mater. Res., 1997, 12, 2743–2450.

19. T. Cheng and R. Raj: J. Am. Ceram. Soc., 1989, 72, 1649–1655.

20. C. H. Hsueh and A. G. Evans: J. Am. Ceram. Soc., 1985, 68, 120–

126.

21. Y. Wang, G. Zhang and J. Ma: Mater. Sci. Eng. B, 2002, B94,

48–53.

22. A. Sutono, D. Heo, Y. J. E. Chen and J. Laskar: IEEE Trans.

Microwave Theory Tech., 2001, 49, 1715–1724.

23. M. Ito, K. Maruhashi, K. Ikuina, N. Senba, N. Takahashi and K.

Ohata: Int. IEEE MTT-S Microwave Symp. Digest, 2000, 1,

57–60.

24. C. H. Lee, A. Sutono, S. Han and J. Laskar: Int. IEEE MTT-S

Microwave Symp. Digest, 2001, 2, 945–948.

25. A. I. Kingon and S. Srinivasan: Nature Mater., 2005, 4, 233–237.

26. V. Gektin, A. Bar-Cohen and S. Witzman: IEEE Trans. Compon.

Packag. Technol. A, 1998, 21A, 577–584.

27. B. Schwartz: Am. Ceram. Soc. Bull., 1984, 63, 577–581.

28. L. Devlin, G. Pearson and J. Pittock: Proc. 38th IMAPS Nordic

Conf., Oslo, Norway, September 2001, IMAPS, 96–110.

29. S. H. Hall, G. W. Hall and J. A. McCall: ‘A high speed digital

system design: a hand book of interconnect theory and design

practices’, 91–92; 2000, New York, John Wiley & Sons.

30. H. Kagata, T. Inoue and J. Kato: Jpn J. Appl. Phys., 1992, 31,

3152–3155.

31. R. L. Whalers, S. J. Stein, Y. D. Huang and M. R. Heinz: ‘Lead

free multilayer system for telecommunications’; 2001, Prussia,

Electro-Science Laboratories.

32. D. I. Amey, M. Y. Keating, M. A. Smith, S. J. Horowitch, P. C.

Donahue and C. R. Needes: Proc. Int. Symp. on

‘Microelectronics’, Boston, MA, USA, September 2000, IMAPS,

654–658.

33. R. Brown: Proc. RF Design ’97 Conf. and Exposit., Englewood,

FL, USA, 1997, 209–221.

34. R. Kulke, W. Simon, C. Gunner, G. Mollenbeck, D. Kother and

M. Rittweger: Proc. IMAPS-Nordic, Stockholm, Sweden,

September 2002, IMAPS, 97–102.

35. C. Wang and K. A. Zaki: Proc. Int. IEEE MTT-S Microwave

Symp. Digest, 1993, 3, 1041–1044.

36. H. Jantunen and A. Turunen: US Patent 5302924, 1994, USA.

37. H. Jantunen: ‘A novel low temperature cofiring ceramic (LTCC)

material for telecommunication devices’, PhD thesis, University of

Oulu, Oulu, Finland, 2001, available at: http://herkules.oulu.fi/

isbn951426553X/isbn951426553X.pdf

38. J. P. Sommer, B. Michel, U. Goebel and J. Jelonnek: Proc. 7th

Soc. Conf. on ‘Thermal and thermomechanical phenomena in

electronic systems’, Las Vegas, NV, USA, May 2000, ITHERM,

355–360.

39. C. B. D. Antonio, D. N. Bencoe and K. G. Ewsuk: Proc. Conf.

SPIE, Bellingham, WA, USA, 2003, SPIE, 160.

40. S. Knickerbocker, A. H. Kumar and L. W. Herron: Am. Ceram.

Soc. Bull., 1993, 72, 90–95.

41. Ferro Coporation: ‘FERRO-TAPE-A6’, Technical publication,

Ferro Coporation, Santa Barbara, CA, USA, 1996.

42. J. H. Jean, T.-H. Kuan and C.-R. Chang: Mater. Chem. Phys.,

1995, 41, 123–127.

43. K. Niwa, Y. Imanaka, N. Kamehara and S. Aoki: ‘Advances in

ceramics’, (ed. M. P. Yan et al.), Vol. 26, 323; 1989, Columbus,

The American Ceramic Society



44. A. H. Kumar, P. W. McMillan and R. R. Tummala: US Patent

4301324, 1981, USA.

45. O.-H. Kwon and G. L. Messing: J. Am. Ceram. Soc., 1990, 73,

275–281.

46. V. K. Singh: J. Am. Ceram. Soc., 1981, 64, C133–C135.

47. K. G. Ewsuk and L. W. Harrison: ‘Advances in ceramics’, (ed. C.

Handwerker et al.), Vol. 29, 356; 1990, Westerville, OH, The

American Ceramic Society.

48. W. D. Kingery, E. Niki and M. D. Narasimhan: J. Am. Ceram.

Soc., 1961, 44, 29–34.

49. R. M. German: ‘Liquid phase sintering’, 65–151; 1985, New York,

Plenum Press.

50. J.-H. Jean and T. K. Gupta: J. Mater. Sci., 1992, 27, 1575–1584.

51. J.-H. Jean and T. K. Gupta: J. Mater. Sci., 1992, 27, 4967–4973.

52. J.-H. Jean and T. K. Gupta: J. Mater. Res., 1994, 9, 771–780.

53. J-H. Jean and T. K. Gupta: J. Mater. Res., 1994, 9, 486–492.

54. J.-H. Jean and S.-C. Lin: J. Mater. Res., 1999, 14, 1359–1363.

55. M. Eberstein and W. A. Schiller: Glass Sci. Technol., 2003, 76, 8–

16.

56. M. Eberstein and W. A. Schiller: Keramische Zeitschrift, 2003, 55,

344–348.

57. A. L. Eustice, S. J. Horowitz, J. J. Stewart, A. R. Travis and H. T.

Sawhill: Proc. 36th Conf. on ‘Electronic component’, Seattle, WA,

USA, May 1986, IEEE, 37–67.

58. T. Noro and H. Tozaki: Japanese Patent No. 6070799A, 1986,

Japan.

59. Y. Imanaka, S. Aoki, N. Kamehara and K. Niwa: J. Ceram. Soc.

Jpn, 1987, 95, 1119–1121.

60. Y. Imanaka, K. Yamazaki, S. Aoki, N. Kamehara and K. Niwa:

J. Ceram. Soc. Jpn, 1989, 97, 309–313.

61. S. Nishigaki, S. Yano, J. Fukuta, M. Fukuyama and T. Fuwa:

Proc. Conf. ISHM ’85, Reston, VA, USA, November 1985,

ISHM, 225–234.

62. G. C. Kuczynski and I. Zaplatynskyj: J. Am. Ceram. Soc., 1956,

39, 349–350.

63. H. Ohsato: J. Ceram. Soc. Jpn, 2006, 113, 703–711.

64. Y. Imanaka and N. Kamehara: J. Ceram. Soc. Jpn, 1992, 100,

558–561.

65. J. I. Steinberg, S. J Horowitz and R. J. Bacher: ‘Advances in

ceramics’, (ed. J. B. Blum et al.), Vol. 19; 1998, Westerville, OH,

The American Ceramic Society.

66. R. R. Tummala Rao, P. Garrou, T. Gupta, N. Kuramoto,

K. Niwa, Y. Shimada and M. Terasawa: ‘Ceramic packaging

in: microelectronic packaging hand book: Part II’, (ed. R. R.

Tummala et al.); 1997, New York, Chapman & Hall.

67. Y. Shimada, Y. Shiozawa, M. Sizuki, H. Takimizawa and Y.

Tamashita: Proc. 36th Electron. Compon. Conf., New Orleans,

LA, USA, 1984, IEEE, 395–405.

68. K. H. Yoon, S. J. Yoo, W. S. Kim, J. B. Kim and E. S. Kim: Jpn

J. Appl. Phys., 1999, 38, 5616–5620.

69. W. D. Kingery: J. Appl. Phys., 1959, 30, 301– 306.

70. J.-H. Jean and S.-S. Lin: J. Am. Ceram. Soc., 2000, 83, 1417–1422.

71. C.-S. Chen, C.-C. Chou, W.-J. Shih, K.-S. Liu, C.-S. Chen and I.-

N. Lin: Mater. Chem. Phys., 2003, 79, 129–134.

72. S. Kemethmuller, A. Roosen, F. Goetz-Neunhoffer and

J. Neubauer: J. Am. Ceram. Soc., 2006, 89, 2632–2637.

73. M. Eberstein, J. Moller, J. Wiegmann and W. A. Schiller: CFI-

Ceram. Forum Int., 2003, 80, E39–E46.

74. M.-Z. Jhou and J.-H. Jean: J. Am. Ceram. Soc., 2006, 89, 786–

791.

75. J. M. Wu and H. L. Huang: J. Non-Cryst. Solids, 1999, 260, 116–

124.

76. K. P. Surendran, P. Mohanan and M. T. Sebastian: J. Solid State

Chem., 2004, 177, 4031–4046.

77. T. Takada and K. Kageyama: Jpn J. Appl. Phys., 2005, 44, 6629–

6635.

78. H. Zhu, M. Liu, H. Zhou, L. Li and A. Lv: J. Mater. Sci., 2006,

17, 637–641.

79. B.-H. Jung, S.-J. Hwang and H.-S. Kim: J. Eur. Ceram. Soc.,

2005, 25, 3187–3193.

80. Y.-J. Choi, J.-H. Park, W.-J. Ko, I.-S. Hwang, J.-H. Park, J.-G.

Park and S. Nahm: J. Am. Ceram. Soc., 2006, 89, 562–567.

81. J. H. Park, Y.-J. Choi and J.-H. Park: Mater. Chem. Phys., 2004,

88, 308–312.

82. H. Zhu, M. Lu, H. Zhou, L. Li and A. Lv: J. Mater. Sci., Mater.

Electron., 2006, 17, 637–641.

83. A. Yang, H. Lin, L. Luo and W. Chen: Jpn J. Appl. Phys., 2006,

45, 1698–1701.

84. S.-G. Kim, J.-S. Park, J.-S. An, K. S. Hong, H. Shin and H. Kim:

J. Am. Ceram. Soc., 2006, 89, 902–907.

85. O. Dernovsek, A. Naeini, G. Preu, W. Wersing, M. Eberstein and

W. A. Schiller: J. Eur. Ceram. Soc., 2001, 21, 1693–1697.

86. N. Ichinose and H. Yamamota: Ferroelectrics, 1997, 201, 255–262.

87. H. Tamura, H. Kagata, T. Inoue and I. Kameyama: Jpn J. Appl.

Phys., 1992, 31, 3152–3155.

88. L. Navias and R. L Green: J. Am. Ceram. Soc., 1946, 29, 267–276.

89. J. O. Israd: Proc. Int. Conf. on ‘Comp. Mater. Electron. Pack.

Eng.’, 1961, IEEE, 3636.

90. E. B. Shand: ‘Glass engineering hand book’, (ed. E. B. Shand), 16;

1958, New York, McGraw-Hill.

91. K. Wakino: Proc. ISIF, 1992, 308–335.

92. A. R. von Hippel (ed.): ‘Dielectric materials and applications’;

1954, Cambridge, MIT Press.

93. D. L. Kinser: ‘Physics of electronic ceramics: Part A’, (ed. L. L.

Hench et al.); 1971, New York, Marcel & Dekker.

94. A. I. Berezhoni: ‘Glass ceramics and photo-citalls’, (ed. A. G.

Pincus); 1970, New York, Plenum Press.

95. G. A. Pavlova and V. G. Chistoserdov: ‘Structure of glass’, Vol. 3;

1964, New York, Consultants Bureau.

96. H. Mandai, K. Sugo, K. Tsukamoto, H. Tani and M. Murata:

Proc. IMC, Kobe, Japan, May 1986, 61–64.

97. H. Mandai: Proc. 2nd Int. Cong. on ‘Ceramic science and

technology’, Orlando, FL, USA, November 1990, 83–86.

98. H. Mandai and S. Okube: Ceram. Trans., 1992, 32, 91–101.

99. T. Takada, H. Yammoto and K. Kageyama: Jpn J. Appl. Phys.,

2003, 42, 6162–6167.

100. H. Kagata, R. Saito and H. Katsumura: J. Electroceram., 2004,

13, 277–280.

101. C.-R. Chang and J.-H. Jean: J. Am. Ceram. Soc., 1999, 82, 1725–

1732.

102. Y. Kobayashi and E. Kato: J. Am. Ceram. Soc., 1994, 77, 833–

834.

103. C.-L. Lo, J.-G. Duh, B.-S. Chiou and W.-H. Lee: J. Am. Ceram.

Soc., 2002, 85, 2230–2235.

104. E. S. Lim, B. S. Kim, J.-H. Lee and J.-J. Kim: J. Non-Cryst.

Solids, 2006, 352, 821–826.

105. T. Takada, S. F. Wang, S. Yoshikawa, S.-J. Jang and R. E.

Newnham: J. Am. Ceram. Soc., 1994, 77, 1909–1916.

106. H. Ohsato, T. Tsunooka, M. Ando, Y. Ohishi, Y. Miyauchi and

K. Kakimoto: J. Korean Ceram. Soc., 2003, 40, 350–353.

107. W. C. J. Jei, C. L. Chen and A. Roosen: Key Eng. Mater., 2005,

280–283, 929–934.

108. M.-H. Lim, J.-H. Park, H.-G. Kim and M.-J. Yoo: Proc. IEEE

Int. Conf. on ‘Properties and applications of dielectric materials’,

Nagoya, Japan, June 2003, IEEE, Vol. 2, 757–760.

109. J. J. Seo, D. J. Shin and Y. S. Cho: J. Am. Ceram. Soc., 2006, 89,

2352–2355.

110. C.-L. Chen, W.-J. Wei and A. Roosen: J. Eur. Ceram. Soc., 2006,

26, 59–65.

111. I. N. Chakraborty, J. E. Shelby and R. A. Condrate: J. Am.

Ceram. Soc., 1984, 67, 782–785.

112. Y.-C. Fang and J.-H. Jean: Jpn J. Appl. Phys., 2006, 45, 6357–

6361.

113. S. Dai, R.-F. Huang and D. L Wilcox: J. Am. Ceram. Soc., 2002,

85, 828–832.

114. D. Wilcox, R.-F. Huang and S. Dai: ‘Ceramic transaction,

multilayer electronic ceramic devices’, (ed. J.-H. Jean et al.), Vol.

97, 201–213; 1998, Westerville, OH, USA, The American Ceramic

Society.

115. S. Dai, R.-F. Huang and D. Wilcox: Proc. 1st China Int. Conf. on

‘High performance ceramics’, Beijing, China, October 1998.

116. E. A. Barringer and H. K. Bowen: J. Am. Ceram. Soc., 1982, 65,

C199–C201.

117. H. Hahn, J. Logas and R. S. Averback: J. Mater. Res., 1990, 5,

609–614.

118. D.-W. Kim, T. G. Kim and K. S. Hong: Mater. Res. Bull., 1999,

34, 771–781.

119. D.-W. Kim, B. Park, J.-H. Chung and K. S Hong: Jpn J. Appl.

Phys., 2000, 39, 2696–2700.

120. S. Yano, N. Hirofumi, Y. Komaki and T. Hirai: US Patent

5232765, 1993, USA.

121. S.-H. Yoon, D.-W. Kim, S.-Y. Cho and K. S. Hong: J. Eur.

Ceram. Soc., 2003, 23, 2549–2552.

122. J.-H. Jean and S.-C. Lin: J. Mater. Res., 1999, 14, 1359–1363.

123. X. M. Cui, J. Zhou, C. L. Miao and J. H. Shen: Rare Earth Mater.

Eng., 2005, 34, 410–415.

124. J.-H. Jean and T. H. Kuan: Jpn J. Appl. Phys., 1995, 34, 1901–

1905.

125. Y. Miyauchi and T. Arashi: J. Jpn Soc. Powder Powder Metall.,

2005, 52, 271–275.



126. D. M. Mattox, S. R. Gurkovich, J. A. Olenik and K. M. Mason:

Ceram. Eng. Sci. Proc., 1988, 9, 1567–1578.

127. R. A. Gudla: Am. Ceram. Soc. Bull. , 1971, 50, 555–557.

128. M. G. M. U. Ismail and H. Aria: J. Ceram. Soc. Jpn, 1992, 100,

1385–1389.

129. C.-L. Lo, J.-G. Duh, B.-S. Chiou and W.-H. Lee: Mater. Res.

Bull., 2002, 37, 1949–1960.

130. C.-L. Lo, J.-G. Duh, B.-S. Chiou and W.-H. Lee: J. Mater. Sci.,

2002, 38, 693–698.

131. V. M. F. Marques, D. U. Tulyaganov, S. Agathopoulos, V. K.

Gataullin, G. P. Kothoyal and J. M. F. Ferreira: J. Eur. Ceram.

Soc., 2006, 26, 2503–2510.

132. I. Levin, T. G. Amos, J. C. Nino, T. A Vanderah, I. M. Reaney,

C. A. Randall and M. T. Lanagan: J. Mater. Res., 2002, 17, 1406–

1411.

133. M. Valant and P. K. Davies: J. Am. Ceram. Soc., 2000, 83, 147–

153.

134. H.-J. Youn T. Sogabe, C. A. Randall, T. R. Shrout and M. T.

Lanagan: J. Am. Ceram. Soc., 2001, 84, 2557–2562.

135. H. Du, X. Yao and L. Zhang: Ceram. Int., 2002, 28, 231–234.

136. H. C. Ling, M. F. Yan and W. W. Rhodes: J. Mater. Res., 1990, 5,

1752–1762.

137. M. F. Yan, H. C. Ling and W. W. Rhodes: J. Am. Ceram. Soc.,

1990, 73, 1106–1106.

138. X. Wang, H. Wang and X. Yao: J. Am. Ceram. Soc., 1997, 80,

2745–2748.

139. D. Liu, Y. Liu, S.-Q. Huang and X. Yao: J. Am. Ceram. Soc.,

1993, 76, 2129–2132.

140. S. L. Swartz and T. R. Shrout: US Patent 5449652, 1994, USA.

141. D. P. Cann, C. A. Randall and T. R. Shrout: Solid State

Commun., 1996, 100, 529–534.

142. H. J. Youn, C. A. Randall, A. Chen, T. R. Shrout and M. T.

Lanagan: J. Mater. Res., 2002, 17, 1502–1506.

143. H. B. Hong, D.-W. Kim and K. S. Hong: Jpn J. Appl. Phys., 2003,

42, 5172–5175.

144. H. Wang, H. Du, Z. Peng, M. Zhang and X. Yao: Ceram. Int.,

2004, 30, 1225–1229.

145. B. Shen, X. Yao, L. Kang and D. Peng: Ceram. Int., 2004, 30,

1203–1206.

146. H. Wang, Z. Peng, H. Du, T. Yao and X. Yao: Ceram. Int., 2004,

30, 1219–1223.

147. S.-Y. Chen and Y.-J. Lin: Jpn J. Appl. Phys., 2001, 40, 3305–3310.

148. G.-K. Choi, D.-W. Kim, S.-Y. Cho and K. S. Hong: Ceram. Int.,

2004, 30, 1187–1190.

149. E. A. Nenesheva and N. F. Kartenko: J. Eur. Ceram. Soc., 2006,

26, 1929–1922.

150. W. F. Su and S. C. Lin: J. Eur. Ceram. Soc., 2003, 23, 2593–2596.

151. C. A. Randall, J. C. Nino, A. Baker, H.-J. Youn, A. Hitomi, R.

Thayer, L. F. Edge, T. Sogabe, D. Anderson, T. R. Shrout, S.

Trolier-McKinstry and M. T. Lanagan: Am. Ceram. Soc. Bull.,

2003, 82, 644–652.

152. A. Baker, M. Lanagan, C. Randall, E. Semouchkina, G.

Semouchkin, K. Z. Rajab, R. Eitel, R. Mitra, S. Rhee, P.

Geggier, C. Duschl and G. Fuhr: Int. J. Appl. Ceram. Technol.,

2005, 2, 514–520.

153. N. Wang, M.-Y. Zhao, W. Li and Z.-W. Yin: Ceram. Int., 2004,

30, 1017–1022.

154. Y.-C. Chen, W.-C. Tzou, C.-F. Yang and P.-S. Cheng: Jpn J.

Appl. Phys., 2001, 40, 3252–3155.

155. H. R. Lee, K. H. Yoon and E. S. Kim: Jpn J. Appl. Phys., 2003,

42, 6168–6171.

156. E. S. Kim and W. Choi: J. Eur. Ceram. Soc., 2006, 26, 1761–1766.

157. C.-L. Huang, M.-H. Weng and C.-C. Yu: Ceram. Int., 2001, 27,

343–350.

158. C.-L. Huang, M.-H. Weng and C.-C. Wu: Jpn J. Appl. Phys.,

2000, 39, 3506–3510.

159. C.-L. Huang and M.-H. Weng: Mater. Lett., 2000, 43, 32 –35.

160. N. Wang, M.-Y. Zhao, Z.-W. Yin and W. Li: Mater. Res. Bull,

2004, 39, 439–448.

161. C.-L. Huang, M.-H. Weng and G.-M. Shan: J. Mater. Sci.,

Mater. Electron., 2000, 35, 5443 –5447.

162. D. Shihua, Y. Xi and Y. Yang: Ceram. Int., 2004, 30, 1195–1198.

163. H. Ohsato: J. Ceram. Soc. Jpn, 2006, 113, 703–711.

164. J.-M. Yoon, J.-A. Lee, J.-H. Lee, J.-J. Kim and S.-H. Cho: J. Eur.

Ceram. Soc., 2006, 26, 2129–2133.

165. J.-B. Lim, K.-H. Cho, S. Nahm, J.-H. Paik and J.-H. Kim: Mater.

Res. Bull., 2006, 41, 1868–1874.

166. I.-S. Cho, D.-W. Kim, J.-R. Kim and K. S. Hong: Ceram. Int.,

2004, 30, 1181–1185.

167. C. F. Yang, L. Wu and T. S. Wu: J. Mater. Sci., 1992, 27, 6573–

6578.

168. C.-C. Cheng, T. Hsieh, I.-N. Lin: J. Eur. Ceram. Soc., 2004, 24,

1787–1790.

169. C.-C. Cheng, T.-E. Hsieh and I.-N. Lin: J. Eur. Ceram. Soc., 2003,

23, 2553–2558.

170. C.-C. Cheng, T.-E. Hsieh and I.-N. Lin: Mater. Chem. Phys.,

2003, 79, 119–123.

171. H. Choy, Y. S. Han, J. H. Sohn and M. Itoh: J. Am. Ceram. Soc.,

1995, 78, 1169–1172.

172. S. Nishigaki, S. Yano, H. Kato, T. Hirai and T. Nomura: J. Am.

Ceram. Soc., 1988, 71, C-11–C-16.

173. S.-F. Wang, C.-C. Chiang and C.-H. Wang: Mater. Chem. Phys.,

2003, 79, 256–260.

174. W. Huang, K.-S. Liu, L.-W. Chu, G.-H Hsiue and I.-N. Lin:

J. Eur. Ceram. Soc., 2003, 23, 2559–2564.

175. J.-A. Lee, J.-H. Lee and J.-J. Kim: J. Eur. Ceram. Soc., 2006, 26,

2111–2115.

176. Y.-G. Choi, J.-H. Park, W.-J. Ko, J.-H. Park, S. Nahm and J.-G.

Park: J. Electroceram., 2005, 14, 157–162.

177. M. Maeda, T. Yamamura and T. Ikeda: Jpn J. Appl. Phys., 1987,

26, 76–79.

178. H. J. Lee, K. S. Hong, S. J. Kim and I. T. Kim: Mater. Res. Bull.,

1997, 32, 847–855.

179. D.-W. Kim, K. H. Ko and K. S. Hong: J. Am. Ceram. Soc., 2001,

84, 1286–1290.

180. S.-H. Wee, D.-W. Kim, S.-I. Yoo and K. S. Hong: Jpn J. Appl.

Phys., 2004, 43, 3511–3515.

181. J. Wang, Z. Yue, Z. Gui and L. Li: J. Alloys Compd, 2005, 392,

263–267.

182. D. W. Kim, D. Y. Kim and K. S. Hong: J. Mater. Res., 2000, 15,

1331–1335.

183. D.-W. Kim, H. B. Hong and K. S. Hong: Jpn J. Appl. Phys., 2002,

41, 1465–1469.

184. M.-C. Wu, K.-T. Huang and W.-F. Su: Mater. Chem. Phys., 2006,

98, 406–409.

185. Y.-C. Lee, C.-H. Lin and I.-N. Lin: Mater. Chem. Phys., 2003, 79,

124–128.

186. R. C. Pullar, C. Lai, F. Azough, R. Freer and N. M. Alford:

J. Eur. Ceram. Soc., 2006, 26, 1943–1946.

187. D.-W. Kim, H. B. Hong, K. S. Hong, C. K. Kim and D. J. Kim:

Jpn J. Appl. Phys., 2002, 41, 6045–6048.

188. H. Sreemoolanathan, M. T. Sebastian and P. Mohanan: Mater.

Res. Bull., 1995, 30, 653–658.

189. R. Ratheesh, M. T. Sebastian, P. Mohanan, M. E. Tobar,

J. Hartnett, R. Woode and D. G. Blair: Mater. Lett., 2000, 45,

279–285.

190. D.-W. Kim, H. J. Yoon, K. S. Hong and C. K. Kim: Jpn J. Appl.

Phys., 2002, 41, 3812–3816.

191. D.-W. Kim, K. S. Hong, C. S. Yoon and C. K. Kim: J. Eur. Cer

Soc., 2003, 23, 2597–2601.

192. I. S. Kim, W.-H. Jung, Y. Inaguma, T. Nakamura and M. Itoh:

Mater. Res. Bull., 1995, 30, 307–316.

193. C.-S. Chen, C.-C. Chou, C.-S. Chen and I.-N. Lin: J. Eur. Ceram.

Soc., 2004, 24, 1795–1798.

194. Q.-L. Zhang, H. Yang and J.-X.Tong: Mater. Lett., 2006, 60,

1188–1191.

195. H.-K. Shin, H. Shin, H. S. Jung, S.-Y. Cho, J.-R. Kim and K. S.

Hong: Mater. Res. Bull., 2006, 41, 1206–1214.

196. H. Jantunen, R. Rautioaho, A. Uusimaaki and S. Leppavuori:

J. Am. Ceram. Soc., 2000, 83, 2855–2857.

197. H. Jantunen, A. Uusimaki, R. Rautioaho and S. Leppavuori:

J. Am. Ceram. Soc., 2002, 85, 697–699.

198. H. Jantunen, A. Uusimaki, R. Rautioaho and S. Leppavuori:

J. Eur. Ceram. Soc., 2000, 20, 2331–2336.

199. T. Hu, R. Rautioaho, H. Jantunen, S. Leppavuori, K.

Soponmanee and S. Sirisoonthorn: Ceram. Int., 2005, 31, 85–93.

200. Y.-J. Choi, J.-H. Park, J.-H. Park and J.-G. Park: Mater. Lett.,

2004, 58, 3102–3106.

201. S. Hirano, T. Hayashi and A. Hattori: J. Am. Ceram. Soc., 1991,

74, 1320–1324.

202. T. Takada, S.-F. Wang, S. Yoshikawa, S.-J. Jang and R. E.


203. J.-H. Jean and S.-S. Lin: J. Am. Ceram. Soc., 2000, 83, 1417–1422.

204. C.-L. Huang and M.-H. Weng: Mater. Res. Bull., 2000, 3, 1881–

1888.

205. C.-L. Huang, M.-H. Weng, C.-C. Wu and C.-C. Wei: Jpn J. Appl.

Phys., 2001, 40, 698–702.

206. C.-L. Huang, M.-H. Weng and H.-L. Chen: Mater. Chem. Phys.,

2001, 71, 17–22.



207. Y.-H. Wang, S.-F. Wang and C.-K. Wen: Mater. Sci. Eng. A,

2006, A426, 143–146.

208. S. X. Zhang, J. B. Li and H. Z. Zhai: Mater. Chem. Phys., 2002,

77, 470–475.

209. G. Bayer: Fortschr. Miner., 1969, 46, 42.

210. M. Udovic, M. Valant and D. Suvorov: J. Eur. Ceram. Soc., 2001,

21, 1735–1738.

211. S. Yamanaka and M. Miyake: J. Less-Common Met., 1990, 159,

179–189.

212. G. Meunier and J. Galy: Acta Crystallogr. Sect. A, Found.

Crystallogr., 1971, 27A, 602–608.

213. D.-K. Kwon, M. T. Lanagan and T. R. Shrout: J. Ceram. Soc.

Jpn, 2005, 113, 216–219.

214. M. Valant and D. Suvorov: J. Eur. Ceram. Soc. 2004, 24, 1715–

1719.

215. D.-K. Kwon, M. T. Lanagan and T. Shrout: J. Am. Ceram. Soc.,

2005, 88, 3419–3422.

216. M. Udovic, M. Valant and D. Suvorov: J. Am. Ceram. Soc., 2004,

87, 591–597.

217. M. Valant and D. Suvorov: J. Am. Ceram. Soc., 2001, 84, 2900–

2904.

218. O. Yamaguchi, M. Morimi, H. Kawabata and K. Shimizu: J. Am.

Ceram. Soc., 1987, 70, C-97–C-98.

219. Y. S. Chang, Y. H .Chang, I. G. Chen, G. J. Chen, Y. L. Chai,

S. Wu and T. H. Fang: J. Alloys Compd, 2003, 354, 303–309.

220. K. Haga, T. Ishiji, J. Mashiyama and T. Ikeda: Jpn J. Appl. Phys.,

1992, 31, 3156–3159.

221. A. Golovochanski, H. T. Kim and Y. H. Kim: J. Korean Phys.

Soc., 1998, 32, S1167–S1169.

222. H. T. Kim, S. H. Kim, S. Nahm, J. D. Byun and Y. Kim: J. Am.

Ceram. Soc., 1999, 82, 3043–3048.

223. Q. L. Zhang, H. Yang, J. L. Zoua and H. P. Wang: Mater. Lett.,

2005, 59, 880–884.

224. A. Chaouchi, M. Aliouat, S. Marinel, S. D. Astorg and

H. Bourahla: Ceram. Int., 2007, 33, 245–248.

225. H. T. Kim, S. Nahm, J. D. Byun and Y. Kim: J. Am. Ceram. Soc.,

1999, 82, 3476–3480.

226. Y.-C. Lee, W.-H. Lee and F.-T. Shiao: Jpn J. Appl. Phys., 2004,

43, 7596–7599.

227. Y.-C. Lee and W.-H. Lee: Jpn J. Appl. Phys., 2005, 44, 1838–1843.

228. J.-W. Choi, C.-Y. Kang, S.-J. Yoon, H.-J. Kim, H.-J. Jung and

K. H. Yoon: J. Mater. Res., 1999, 14, 3567–3570.

229. P. Liu, E. S. Kim and K. H. Yoon: Jpn J. Appl. Phys., 2001, 40,

5769–5773.

230. P. Liu, H. Ogawa, E. S. Kim and A. Kan: J. Eur. Ceram. Soc.,

2003, 23, 2417–2421.

231. J. W. Choi, C. Y. Kang, S. J. Yoon, H. J. Kim and K. H. Yoon:

Ferroelectrics, 2001, 262, 1141–1146.

232. P. Liu, E. S. Kim, S. G. Kang and H. S. Jang: Mater. Chem.

Phys., 2003, 79, 270–272.

233. J.-Y. Ha, J.-W. Choi, S.-J. Yoon, D. J. Choi, K. H Yoon and

H.-J. Kim: J. Eur. Ceram. Soc., 2003, 23, 2413–2416.

234. J.-Y. Ha, J.-W. Choi, C.-Y. Kang, S.-J. Yoon, D. J. Choi and H. J.

Kim: Jpn J. Appl. Phys., 2005, 44, 1322–1325.

235. Q. H. Yang, E. S. Kim, Y. J. Kim and P. K. Kim: Mater. Chem.

Phys., 2003, 79, 236–238.

236. E. S. Kim, B. S. Chun, J. D. Kim and K. H. Yoon: Mater. Sci.

Eng. B, 2003, B99, 243–246.

237. Y. Yoshida, N. Hara, T. Takada and A. Seki: Jpn J. Appl. Phys.,

1997, 36, 6818–6823.

238. C.-H. Wei and J.-H. Jean: J. Am. Ceram. Soc., 2003, 86, 93–98.

239. A. Yokoi, H. Ogawa, A. Kan, H. Ohsato and Y. Higashidav:

J. Ceram. Soc. Jpn, 2004, 112, S1633–S1636.

240. A. Kan, H. Ogawa, A. Yokoi and H. Ohsato: Jpn J. Appl. Phys.,

2003, 42, 6154–6157.

241. A. Yokoi, H. Ogawa, A. Kan, H. Ohsato and Y. Higashida:

J. Eur. Ceram. Soc., 2005, 25, 2871–2875.

242. M. Valant, D. Suvorov and A. Meden: J. Am. Ceram. Soc., 1999,

82, 81–87.

243. M. Valant, D. Suvorov and A. Meden: J. Am. Ceram. Soc., 1999,

82, 88–93.

244. M. Valant, D. Suvorov, C. Hoffmann and H. Sommariva: J. Eur.

Ceram. Soc., 2001, 21, 2647–2651.

245. M. H. Framcombe and B. Lewis: Acta Crystallogr. Sect. A,

Found. Crystallogr., 1958, 11A, 175–178

246. Y. Sakabe, T. Takeda, Y. Ogio and N. Wada: Proc. 10th US–

Japanese Semin. on ‘Dielectric and piezoelectric ceramics’,

Providence, RI, USA, September 2001, 63–66.

247. H. T. Kim, T. R. Shrout, C. Rindall and M. Lanagan: J. Am.

Ceram. Soc., 2002, 85, 2738–2744.

248. A. Borisevich and P. K. Davies: J. Eur. Ceram. Soc., 2000, 21,

1719–1722.

249. A. Borisevich and P. K. Davies: J. Am. Ceram. Soc., 2002, 85,

2487–2491.

250. A. Borisevich and P. K. Davies: J. Am. Ceram. Soc., 2002, 85,

573–578.

251. D. H. Kang, K. C. Nahm and H. J. Cha: J. Eur. Ceram. Soc.,

2006, 26, 2117–2121.

252. Q. Zeng, W. Li, J.-L.Shi, J.-K. Guo, M.-W. Zuo and W.-J. Wu:

J. Am. Ceram. Soc., 2006, 89, 1733–1735.

253. Q. Zeng, W. Li, J.-L. Shi and J.-K. Guo: Mater. Lett., 2006, 60,

3203–3206.

254. Q. Zeng, W. Li, J.-L. Shi and J.-K. Guo: J. Am. Ceram. Soc.,

2006, 89, 3305–3307.

255. N. Mori, Y. Sugimoto, J. Harada and Y. Higuchi: J. Eur. Ceram.

Soc., 2006, 26, 1925–1928.

256. N. Mori, Y. Sugimoto, J. Harada and H. Takagi: J. Ceram. Soc.

Jpn Suppl., 2004, 112, (1), S1563–S1566.

257. K. P. Surendran and M. T. Sebastian: J. Appl. Phys. A, 2005, 81A,

823–826.

258. J. Kato, H. Kagata and K. Nishimoto: Jpn J. Appl. Phys., 1992,

31, 3144–3147.

259. S. Kucheiko, J. W. Choi, H. J. Kim, S. J. Yoon and H. J. Jung:

J. Am. Ceram. Soc., 1997, 80, 2937–2940.

260. M. Nakano, K. Suzuki, T. Miura and M. Kobayashi: Jpn J. Appl.

Phys., 1993, 32, 4314–4318.

261. J.-Y. Ha, J.-W. Choi, H.-J. Kim, S.-J. Yoon and K. H. Yoon:

Mater. Chem. Phys., 2003, 79, 261–265.

262. Y. Qiuhong, K. E. Soo and X. Jun: J. Chin. Ceram. Soc., 2002, 31,

554–558.

263. H. M. Zhe, Z. D. Xiang, G. H. Shuang, W. Hao, Z. Tianjing and

Z. Bin: Mater. Sci. Eng. B, 2005, B117, 199–204.

264. H. Kagata and J. Kato: Jpn J. Appl. Phys., 1994, 31, 5466–5465.

265. H. J. Kucheiko, H. J. Kim, S. J. Yoon and H. J. Jung: Jpn J. Appl.

Phys., 1997, 36, 198–202.

266. K.-W. Kang and H. T. Kim: Mater. Res. Bull., 2006, 41, 1385 –

1391.

267. N. Krishnamurti and C. Calvo: Can. J. Chem., 1971, 49, 1629–

1637.

268. R. Umemura, H. Ogawa, H. Ohsato, A. Kan and A. Yokoi:

J. Eur. Ceram. Soc., 2005, 25, 2865–2870.

269. R. Umemura, H. Ogawa, A. Yokoi, H. Ohsato and A. Kan:

J. Alloys Compd, 2006, 424, 388–393.

270. R. C. Kerby and J. R. Wilson: Can. J. Chem., 1973, 51, 1032–

1040.

271. S. Nomura: Ferroelectrics, 1983, 49, 61–70.

272. T. Kolodiazhnyi, A. Petric, A. Belous, V. Yunov and O.

Yancheevskij: J. Mater. Res., 2002, 17, 3182–3189.

273. J. B. Lim, J.-O. Son, S. Nahm, W. S. Lee, M. J. Yoo, N. K. Kang,

H. J. Lee and Y. S. Kim: Jpn J. Appl. Phys., 2004, 43, 5388–5391.

274. J.-B. Lim, D.-H. Kim, S. Nahm, J.-H. Paik and H.-J. Lee: Mater.

Res. Bull., 2006, 41, 1199–1205.

275. J.-J. Bian, D.-W. Kim and K. S. Hong: Mater. Res. Bull., 2005,

40, 2120–2129.

276. D.-H. Kim, C. An, K.-S. Bang, J.-C. Kim and H.-G. Lee: Solid

State Phenomena, 2003, 317, 90–91.

277. C. R. Needs, C. B. Wang, K. W. Hang, M. F. Barker, D. I. Amey,

M. A. Smith and K. E. Souders: Proc. Conf. on ‘Ceramic

interconnect technology’, Denver, CO, USA, April 2003, IMAPS,

126.

278. F. Lautzenhiser and E. Amaya: Proc. SPIE – Int. Soc. Optical

Eng., 2002, 4828, 143–149.

279. A. Mohanram, S.-J. Lee, G. L. Messing and D. J. Green: J. Am.

Ceram. Soc., 2006, 89, 1923–1929.

280. A. Mohanram, S.-J. Lee, G. L. Messing and D. J. Green: Acta

Mater., 2005, 53, 2413–5418.

281. R. Zuo, E. Aulbach and J. Rodel: J. Am. Ceram. Soc., 2004, 87,

526–528.

282. G.-Q. Lu, R. C. Sutterlin and T. K. Gupta: J. Am. Ceram. Soc.,

1993, 76, 1907–1914.

283. A. Mohanram, G. L. Messing and D. J. Green: Proc. Int. Conf.

on ‘Microelectronic Packaging Soc. Proc., Washington, DC,

USA, 2002, IMAPS, 772–777.

284. T. J. Garino: Proc. SPIE – Int. Soc. Optical Eng., 2003, 5231, 171–

176.

285. T. Rabe, W. A. Schiller, T. Hocheimer, C. Modes and A. Kipka:

Int. J. Appl. Ceram. Technol., 2005, 2, 374–382.

286. H. Ohsato, T. Tsunooka, Y. Ohishi, Y. Miyauchi, M. Ando and

K. Kakimot: J. Korean Ceram. Soc., 2003, 40, 350–353.



287. T. Okawa, M. Imaeda and H. Ohsato: Jpn J. Appl. Phys., 2000,

39, 5645–5649.

288. H. Ohsato, H. Kato, M. Mizuta, S. Nishigaki and T. Okuda: Jpn

J. Appl. Phys., 1995, 34, 5413–5417.

289. Y. J. Wu and X. M. Chen: J. Mater. Res., 2001, 16, 1734–1738.

290. J. H. Jang: J. Am. Ceram. Soc., 2004, 87, 1466–1470.

291. M. Ohsahi, H. Ogawa, A. Kan and E. Tanaka: J. Eur. Ceram.

Soc., 2005, 25, 2877–2881.

292. C.-C. Chiang, S. F. Wang, Y.-R. Wang and W.-C. J. Wei: Ceram.

Int., 2007, to be published.

293. M. M. Krzmanc, M. Valant and D. Suvorov: J. Eur. Ceram. Soc.,

2005, 25, 2835–2838.

294. M. M. Krzmanc, A. Meden and D. Suvorov: J. Eur. Ceram. Soc.,

2007, 27, 2957–2962.

295. J.-M. Wu and H.-L. Huang: J. Mater. Res., 2000, 15, 222–227.

296. M.-H. Lim, J.-H. Park, H.-G. Kim and M.-J. Yoo: Proc. 7th Int.

Conf. on ‘Properties and applications of dielectric materials’,

Nagoya, Japan, June 2003, IEEE, Vol.2, 757–760.

297. J.-L. Zou, Q.-L. Zhang, H. Yang and H.-P. Sun: Jpn J. Appl.

Phys., 2006, 45, 4143–4145.

298. G.-K. Choi, J.-R. Kim, S. H. Yoon and K. S. Hong: J. Eur.

Ceram. Soc., 2007, 27, 3063–3067.

299. J.-B. Lim, Y. H. Jeong, N.-H. Nguyen, S. Nahm, J.-H. Paik, J.-H.

Kim and H.-J. Lee: J. Eur. Ceram. Soc., 2007, 27, 2875–2879.

300. R. Umemura, H. Ogawa and A. Kan: J. Eur. Ceram. Soc., 2006,

26, 2063–2068.

301. S. Nishigaki, S. Yano, H. Kato, T. Hirai and S. Nomura: J. Am.

Ceram. Soc., 1988, 71, C11–C17.

302. J. S. Kim, J. C. Lee, C. I. Cheon and C. H. Lee: Proc. Int. Symp.

on ‘Research reactor and neutron science’, Daejeon, Korea, April

2005, 682–685.

303. T. Sugiyama, T. Tsunooka, K. Kakimoto and H. Ohsato: J. Eur.

Ceram. Soc., 2006, 26, 2097–2100.

304. E. S. Kim, S.-H. Kim and B. I. Lee: J. Eur. Ceram. Soc., 2006, 26,

2101–2104.

305. Y. Higuchi, Y. Sugimoto, J. Harada and H. Tamura: J. Eur.

Ceram. Soc., 2007, 27, 2785–2788.

306. S.-I. Yoo: Proc. Korea–UK Semin. on ‘Microwave dielectric

materials’, Seoul, Korea, February 2003, Seoul Kyoyuk Munhwa-

Hoekwan.

307. J. Bang: J. Eur. Ceram. Soc., 2007, 27, 3855–3859.

308. R. C. Pullar, S. Farrah and N. M. Alford: J. Eur. Ceram. Soc.,

2007, 27, 1059–1063.

309. S. Thomas and M. T. Sebastian: Mater. Res. Bull., 2007, to be

published.

310. D. K. Kwon, M. T. Lanagan and T. R. Shrout: Mater. Lett.,

2006, 61, 1827–1831.

311. I.-S. Cho, S.-K. Kang, D.-W. Kim and K. S. Hong: J. Eur.

Ceram. Soc., 2006, 26, 2007–2010.

312. G.-K. Choi, S.-Y. Cho, J.-S. An and K. S. Hong: J. Eur. Ceram.

Soc., 2006, 26, 2011–2015.

313. A. Kan, H. Ogawa and H. Ohsato: J. Ceram. Soc. Jpn Suppl.,

2004, 11, S1622–S1626.

314. H. Ogawa, A. Yokoi, R. Unemura and A. Kan: J. Eur. Ceram.

Soc., 2007, 27, 3099–3104.

315. H. Ogawa, A. Yoki, R. Umemura and A. Kan: J. Eur. Ceram.

Soc., 2007, 27, 3099–3104.

316. S. H. Yoon, D.-W. Kim, S.-Y. Cho and K. S. Hong: J. Eur.

Ceram. Soc., 2006, 26, 2051–2054.

317. S. J. Hwang, Y.-J. Kim and H. S. Kim: J. Electroceram., 2007, 18,

121–128.

318. R. C. Pullar, J. D. Breeze and N. M. Alford: Key Eng. Mater.,

2002, 224–226, 1–4.

319. A. Yang, H. Lin and W. Chen: Jpn J. Appl. Phys., 2006, 45, 1698–

1701.

320. W. W. Cho, K. Kakemoto and H. Ohsato: Mater. Sci. Eng. B,

2005, B121, 48–53.

321. P. V. Bijumon, S. Solomon, M. T. Sebastian and P. Mohanan:

J. Mater. Sci., 2003, 14, 5–8.

322. Y.-R. Wang, S.-F. Wang and C.-K. Wen: Mater. Sci. Eng. A,

2006, A426, 143–146.

323. Y.-R. Wang, S.-F. Wang and Y.-M. Lin: Ceram. Int., 2005, 31,

905–907.

324. Q. L. Zhang and H. Yang: J. Mater. Sci. Mater. Electr., 2007, to

be published.

325. X. Liu, F. Gao, L. Zhao and M. Zhao: J. Electroceram., 2007, 18,

103–109.

326. Y.-C. Choi, J.-H. Park, S. Nahm and J-G. Park: J. Eur. Ceram.

Soc., 2007, 27, 2017–2024.

327. H. Shin, H.-K. Shin, H. S. Jung, S.-Y. Cho and K. S. Hong:

Mater. Res. Bull., 2005, 40, 2021–2028.

328. J. X. Tong, Q. L. Zhang, H. Yang and J. L. Zou: Mater. Lett.,

2005, 59, 3252–3255.

329. N. I. Santha and M. T. Sebastian: unpublished work.

330. Y.-L. Chai, Y.-S. Chang, Y.-J. Hsiao and Y.-C. Lian: Mater. Res.

Bull., 2008, 43, 257.

331. C.-L. Huang, R. J. Lin and J. H. Wang: Jpn J. Appl. Phys., 2001,

41, 758–762.

332. T. Takada, S. F. Wang, S. Yoshikawa, S.-J. Jang and R. E.


333. M.-H. Kim, S. Nahm, W. S. Sung, M.-J. Yoo, N.-K. Kang,

H.-T. Kim and H.-J. Lee: Jpn J. Appl. Phys., 2005, 44, 3091–

3094.

334. E. Guan, W. Chen and L. Luo: Ceram. Int., 2007, 33, 1145–1148.

335. Y.-C. Lee, W.-H. Lee and F.-S. Shieuc: Jpn J. Appl. Phys., 2002,

41, 6049–6053.

336. Y.-C. Lee, W.-H. Lee and F.-S. Shiuc: J. Eur. Ceram. Soc., 2005,

25, 3459–3468.

337. Y.-C. Lee, W.-H. Lee and F.-S. Shieuc: Jpn J. Appl. Phys., 2003,

42, 1311–1314.

338. J. J. Jiang, H. B. Gao and X. W. Wang: Mater. Res. Bull., 2004,

39, 2127–2135.

339. P. S. Anjana and M. T. Sebastian: unpublished work.

340. M. H. Kim, J. H. Jeong, S. Nahm, H. T. Kim and H. J. Lee:

J. Eur. Ceram. Soc., 2006, 26, 2139–2142.

341. D.-W. Kim, D.-G. Lee and K. S. Hong: Mater. Res. Bull., 2001,

36, 585–595.

342. S. O. Yoon, J. H. Yoon, K. S. Kim, S. H. Shim and Y. K. Pyeon:

J. Eur. Ceram. Soc., 2006, 26, 2031–2034.

343. J.-X. Tong, Q.-L. Zhang, H. Yang and J.-L. Zou: J. Am. Ceram.

Soc., 2007, 90, 845–849.

344. E. S. Kim and W. Choi: J. Eur. Ceram. Soc., 2006, 26, 1761–

1766.

345. D.-H. Kim, S.-K. Lim, C. An, Y.-S. Lee, K.-S. Bang, J.-C. Kim

and H.-K. Lee: Proc. 7th Int. Conf. on ‘Solid dielectrics’,

Eindhoven, Netherlands, June 2001, IEEE, 195–199.

346. J.-B. Lim, S. Nahm, H.-T. Kim, J.-H. Kim, J.-H. Paik and H.-J.

Lee: J. Electroceram., 2006, 17, 393–397.

347. I. Nishigaki et al.: Proc. 3rd US–Japan Semin. on ‘Dielectric and

piezoelectric ceramics’, Toyama, Japan, November 1986, 55.

348. D.-W. Kim, H. B. Hong and K. S. Hong: Jpn J. Appl. Phys., 2002,

41, 1465–1469.

349. D.-W. Kim, J-R. Kim, S-H.Yoon, K. S. Hong and C. K. Kim:

J. Am. Ceram. Soc., 2002, 85, 2759–2762.

350. P. Liu, H. Ogawa, E. S. Kim and A. Kan: J. Eur. Ceram. Soc.,

2004, 24, 1761–1768.

351. J.-R. Kim, D. W. Kim, H. S. Jung and K. S. Hong: J. Eur. Ceram.

Soc., 2006, 26, 2105–2109.

352. J.-R. Kim, D.-W. Kim, S. H. Yoon and K. S. Hong:

J. Electroceram., 2006, 17, 439–443.

353. Q. Zeng, W. Li, J.-L. Shi and J.-K. Guo: Mater. Lett., 2006, 60,

3203–3206.

354. D. Shihua, Y. Xi and Y. Yang: Ceram. Int., 2004, 30, 1195–1198.

355. Y. Mao, S. H. Ding, X. Yao and L. Y. Zhang: Mater. Chem.

Phys., 2006, 98, 198–202.

356. S. Hirano, T. Hayashi, K. Kikuta and J. Otsuka: Ceram. Trans.,

1990, 12, 733–740.

357. Q.-L. Zhang and H. Yang: Mater. Res. Bull., 2005, 40, 1891–1898.

358. P. Liu, H. Zhang, H. Ogawa and E. S. Kim: Phys. Status Solidi A,

2004, 201A, 2175–2179.

359. F. Zhao, Z. Yue, J. Pei, Z. Gui and L. Li: J. Solid State Chem.,

2006, 179, 1720–1726.

360. H. P. Wang, Q. L. Zhang, H. Yang and J. L. Zhou: Electron.

Compon. Mater., 2004, 23, 4.

361. Q. Zeng, W. Li, J. L. Shi, X. L. Dong, J.-K. Guo: Mater. Res.

Bull., 2008, 43, 411.

362. H. B. Hong, D. W. Kim and K. S. Hong: Jpn J. Appl. Phys., 2003,

42, 5172.

363. K.-W. Wang, H. T. Kim, M. Lanangan and T. Shrout: Mater.

Res. Bull., 2006, 41, 1385–1391.

364. C. Qin, Z. Yue, Z. Gui and L. Li: Mater. Sci. Eng. B, 2003, B99,

286–289.

365. P. Samoukhina, S. Kamba, S. Santhi, J. Petzelt, M. Valant and

D. Suvorov: J. Eur. Ceram. Soc., 2005, 25, 3085– 3088.

366. Y. J. Wu and X. M. Chen: J. Mater. Res., 2001, 16, 1734–1738.

367. D. H. Kang, K. C. Nam and H. J. Cha: J. Eur. Ceram. Soc., 2006,

26, 2117–2121.

368. D. K. Yim, J.-R. Kim, D.-W. Kim and K. S. Hong: J. Eur.

Ceram. Soc., 2007, 27, 3053–3057.



369. E. S. Kim, H. S. Park and K. H. Kim: Mater. Chem. Phys., 2003,

79, 213–217.

370. Q. Zeng, W. Li, J.-L. Shi, J.-K. Guo, H. Chen and M.-L. Liu:

J. Eur. Ceram. Soc., 2007, 27, 261–265.

371. Y. Ota, K. Kakimoto, H. Ohsato and T. Okawa: J. Eur. Ceram.

Soc., 2003, 24, 1755–1760.

372. A.-K. Axelsson and N. M. Alford: J. Eur. Ceram. Soc., 2006, 26,

1933–1936.

373. G. Huang, D. Zhou, J. Xu, Z. Zheng and S. Gong: Mater. Res.

Bull., 2005, 40, 13–19.

374. M. Valant and D. Suvorov: J. Am. Ceram. Soc., 2003, 86, 939–944.

375. E. S. Kim, J. S. Jeon and K. H. Yoon: J. Eur. Ceram. Soc., 2003,

23, 2583–2587.

376. S. L. Schwartz and T. R. Shrout: US Patent 5449652, 1995, USA.

377. A.-K. Axelsson, M. T. Sebastian and N. M. Alford: J. Korean

Ceram. Soc., 2003, 40, 340–345.



Low loss dielectric materials for LTCC applications: a review

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