Metal Thermal Interface Materials€¦ · Metal Thermal Interface Materials Introduction Liquid Indalloy® Alloys Liquid at Room Temperature Introduction Several very low melting

MetalThermalInterface Materials• LiquidMetal• CompressibleMetal• Solder• TIMFluxes

86W/m•K

Products•Au/SnSolder•In/PbSolders•PureIndium•Informs•SMA-TIM•SACPb-FreeSolders

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www.indium.com/TIM [email protected]

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Metal Thermal Interface Materials RadicallyImprove:

•HeatDissipationEfficiencyinElectronicDevices

• ThermalConductivityforHighPowerDeviceswithPowerDensitiesinExcessof50W/cm2

•End-of-LifePerformanceattheThermalInterface–toAvoidFailuresCommonwithFluidicSolutionsSuchasGreases

•PortableDeviceBatteryPerformance–byReducingThermalResistanceandCoolingFanSize

• PortableDeviceUseProfile–byReducingHeatsinkSizeandMass

•CompliancewithRoHSWhileAccommodatingStepSolderingRequirements

Indium CorporationHasSolutionsfor:•Telecom

•Computing

•Semiconductors

•LEDs

•Photonics

•Medical•Cryogenics•Automotives•PowerDevices

Metal Thermal Interface MaterialsIntroduction Liquid

TypesofMetalTIMs: • Liquid • CompressibleMetal • Solderable • Low-MeltingAlloy

•IncreasedPowerDemands•ReducedPackageSize

Superior Thermal Conductivity

Problem:

Solved.

ApplicationsSomeApplicationsInclude:

•SemiconductorIntegratedCircuits

•PowerQFNs

•PowerDevicetoPCBAttach(TO220,etc.)

•Telecom

•Die-Attach(Photonics,MOSFETS,LEDetc.)

•LaserDiodes

Products•Au/SnSolder

• In/PbSolders

•PureIndium

•Informs

•Sn/PbSolders

•SACPb-FreeSolders

Packaging•TapeandReel

•Syringe

•Bottle

•CustomPackaging

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Metal Thermal Interface MaterialsIntroduction Liquid

Indalloy® Alloys Liquid at Room TemperatureIntroductionSeveralverylowmeltingpointIndalloy® alloysareliquidatroomtemperature.Thesegallium-basedalloysarefindingincreaseduseinvariousapplicationsasareplacementfortoxicmercury,whichhasahighvaporpressureatroomtemperature.Thesealloyshavereducedtoxicityandlowervaporpressurethanmercury.

Excellent Thermal and Electrical ConductivityAlloysystemsthatareliquidatroomtemperaturehaveahighdegreeofthermalconductivityfarsuperiortoordinarynon-metallicliquids.Thisresultsintheuseofthesematerialsforspecificheatconductingand/ordissipationapplications.Otheradvantagesoftheseliquidalloysystemsaretheirinherenthighdensitiesandelectricalconductivities.

Wetting to Metallic and Non-Metallic SurfacesThesealloyswillwetmostmetallicsurfacesonceoxideshavebeensufficientlyremovedfromthesubstratesurface.However,galliumisveryreactivewithsomemetals,evenatroomtemperature.Athightemperatures,galliumdissolvesmostmetals,althoughanumber,includingNa,K,Au,Mg,Pb,NiandinterestinglyHg,areonlyslightlysolubleatmoderatetemperatures.1

Asstated,galliumiscorrosivetoallmetalsexcepttungstenandtantalumwhichhaveahighresistancetocorrosion.Columbium,titaniumandmolybdenumhaveresistancetocorrosionbutlessthantungstenandtantalum.2

Galliumandthegalliumalloys,likeindium,havetheabilitytowettomanynon-metallicsurfacessuchasglassandquartz.Gentlyrubbingthegalliumalloyintothesurfacemayhelpinducewetting.

Note:Thesealloysformathindulllookingoxideskinthatiseasilydispersedwithmildagitation.Theoxide-freesurfacesarebrightandlustrous.

ApplicationsTypicalapplicationsforthesematerialsincludethermostats,switches,barometers,heattransfersystems,andthermalcoolingandheatingdesigns.

Uniquely,theycanbeusedtoconductheatand/orelectricitybetweennon-metallicandmetallicsurfaces.

PackagingAlloysarepackagedinpolyethylenebottlesandshippedinaccordancewithapplicablefederalregulations.

Storage/Shelf LifeUnopenedbottleshaveaguaranteedone-yearshelflife.Itisrecommendedthat,asthealloyisremovedfromthebottle,thevolumebereplacedwithdryargon.Thiswillminimizethepossibilityofoxidationatthesurfaceofthealloy.Ifthealloyhasbeenstoredbelowitsmeltingpointandhassolidified,itshouldbere-meltedandthoroughlyshakenormixedbeforeuse.Careshouldbetakeninreheatingthealloyintheoriginalpackagingprovided.Temperaturesshouldnotexceed65.6°C.

1 .PergamonTextsinInorganicChemistryVolume12,TheChemistryofALUMINUM,GALLIUM,INDIUM,andTHALLIUMbyK.Wade&A.J.Banister,UniversityofDurham,PergamonPress,1975.

2.Lyon,RichardN.,ed.Liquid Metals Handbook.2nded.WashingtonDC:1952

Indalloy Number Type Liquidus Solidus Composition Density

lb/in3SpecificGravity

46L OrdinaryAlloy 7.6°C 6.5°C 61.0Ga/25.0In/13.0Sn/1.0Zn 0.2348 6.50

51 EutecticAlloy 10.7°C 10.7°C 62.5Ga/21.5In/16.0Sn 0.2348 6.50

60 EutecticAlloy 15.7°C 15.7°C 75.5Ga/24.5In 0.2294 6.35

77 OrdinaryAlloy 25.0°C 15.7°C 95Ga/5In 0.2220 6.15

14 PureMetal 29.78°C 29.78°C 100Ga 0.2131 5.904

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Metal Thermal Interface MaterialsCompressible Metal–SMA-TIM Solderable Metal

IntroductionIndium’sSoft Metal Alloy Thermal Interface Materials (SMA-TIM)exhibitsuperiorthermalconductivity,compressibilityandeaseofapplication.SMA-TIMpreformsconstructedofindiumwithourheat-springprocessingtechnologyareahighlyeffectivechoiceforhigh-endcoolingdevices.

Specifications Typical Dimensions 25.4mm x 25.4mm x .05-.3mm (1" x 1" x .002"-.012") Application Pressure >20psi Alloy Purity Level 99.99% In Max. Operational Temp. 140°C Thermal Conductivity 86W/m•K

Compressed Interface ApplicationAnSMA-TIMmadeofindiumoffersuniformthermalresistanceatlowerappliedstressesincompressedinterfaces.Themalleabilityofindiumminimizessurfaceresistanceandincreasesheatflow.Ourpatentpendingheat-springtechnologywillfurtherreducethethermalresistance.

ReliabilityIndium’shigh-endthermalinterfacematerialsdeliversuperiorperformance.AsSMA-TIMproductsaremadeofmetal,theydonotexperiencepumpoutproblemsevenunderpowercycling.Theheat-springmaterial,whichdoesnotcontainsilicone,willconformtosurfaceirregularities,therebyreducingthermalresistancethroughthelifeoftheTIM.Duetoitssolidstate,theSMA-TIMalsoresistsbakeoutasshowninthediagrambelow.

Heat-Spring Baseline Thermal Grease

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Metal Thermal Interface MaterialsCompressible Metal–SMA-TIM Solderable Metal

Properties Indalloy #4 Electrical Conductivity ('% of IACS) (1.72microhms-cm) 24 Thermal Conductivity (W/m•K) (@ 85°C) 86 Coefficient of Thermal Expansion (µin/µin per °C) (@20°C) 29 Density (lb/cu. in.) 0.2641 Mass Density (gm/cm3) 7.31 Tensile Strength (PSI) 273 Shear Strength (PSI) 890 Young's Modulus (PSI X 10x6) 1.57 %Elongation 22 to 41 Brinell Hardness (2mm ball, 4kg load) 0.9 Latent Heat of Fusion (J/g) 28.47 Melting Point (°C) 156.7

Material Safety Data SheetTheMSDSforthisproductcanbefoundonlineathttp://www.indium.com/techlibrary/msds.php

IntroductionThermal interface materialsareusefulforavarietyofapplications,butsolderthermalinterfacematerials(sTIM)areespeciallysuitedtohigh-enddevicecooling.Toimprovepackagereliability,itisespeciallyimportanttochoosetherightalloy.Indium,inparticular,shouldbeconsideredasasTIMbecauseofitshighthermalconductivity,compressibility(SMA-TIM),andeaseofapplication.

Specifications Max. Operational Temp. 125°C Standard Purity Level 99.99% Typical Size 25.4mm x 25.4mm x .05-.3mm (1" x 1" x .002"-.012")

ApplicationsIndiumPreformsmaybeusedinavarietyofprocesses.

•Compressed Between Two Surfaces Without Reflow (SMA-TIM) Soft Metal Alloy-TIM Theextrememalleabilityofindiumallowsittominimizesurfaceresistance–therebyincreasingheatflow.Thegraphbelowdemonstratesthisphenomenon.

•Soldered Between Two Surfaces (sTIM) Solder-TIM Usedtofurtherimprovethermalresistance,thisapplicationmayrequiretheuseofafluxtoreduceoxidesonsolderingsurfaces.

•Cold-WeldingAnotherprocessthatisusedtocreateathermalinterfaceinvolvesreflowingindiumpreformsontoeachsolderablesurface.Then,indium-coatedsurfacesshouldbecleanedandpressedtogethertoformafluxlesscold-weldsolderjoint.(SeetheApplicationNote:Etching Indium to Remove Oxidesformoreinformationaboutthisprocess.)

Storage and PackagingSMA-TIMPreformscomeinavarietyofpackagingoptions,includingtape&reelandcustomadhesivecarriersfordirect-attachtoheat-sinks.Tominimizeexcessivehandlingandoxidationduetoairexposure,itisrecommendedtokeepTIMpreformsintheiroriginalcontainerinacooldryplace.IndiumSMA-TIMs,whenexposedtoair,willself-passivatetoalevelofapproximately10nanometersandwillhaveausefullifeofatleastsixmonths.SMA-TIMscanalsobestoredinaninertatmospheresuchasnitrogen.

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Metal Thermal Interface MaterialsSolderable Flux-Coated Preforms

Selecting DimensionsThelocationofthesolderjointandthevolumeofsolderneededwilldeterminethesizeandshapeofthepreform.Oncetheflatdimensions(diameter,length,width)havebeendetermined,thethicknesscanbeadjustedtoachievethedesiredvolumeofsolder.Generally,forthrough–holeconnections,add10–20%tothecalculatedvolumeforagoodfillet.Forpadtopadjoints,figureabout5%lesssurfaceareathanthepad.

EachSolderPreformshouldhaveaburrtolerancespecified.Youshouldstayasclosetostandardtolerancesaspossibletoavoidaddingcostandleadtimetoyourpreforms.

IndiumCorporationhasanextensivelibraryofsizesandshapesfromwhichyoucanchoose,orwecancreateaset–upspecificallyforyourapplication.Usinganexistingpreformsizecaneliminatetheadditionaltimeassociatedwithcreatinganewset–up.

IntroductionSolderPreformsareusedinavarietyofapplicationsthatrequirepreciseamountsofsolder.

Preformscomeinstandardshapessuchassquares,rectangles,washersanddiscs.Typicalsizesrangefrom.254mm(.010”)upto50.8mm(2”).Smallerandlargersizes,aswellascustomshapes,arealsoavailable.Dimensionscanbeheldtotighttolerancestoassurevolumeaccuracy.

Selecting AlloysAwideassortmentofalloysisavailableinliquidustemperaturesthatrangefrom47°Cto1063°C.Alloyscanbeindium–contained,gold-contained,lead–free,fusibleorstandardtin–lead,aswellasmanyothers.

1.Alloyselectionshouldbebasedonstrengthandotherrequiredphysicalproperties,aswellasthepreferredsolderingtemperatureandtheoperatingtemperatureofthedevicebeingsoldered.Ageneralruleistoselectanalloythatmeltsatleast50°Chigherthantheoperationaltemperatureofthepartbeingsoldered.

2.Next,considerthematerialsbeingsolderedandwhatsolderismostcompatiblewiththem.Forexample,tin–basedsolderswillscavengethegoldfromgold-platedparts,formingbrittleintermetallics,soindium-basedsoldersaregenerallyrecommendedinthesecases.

3.Metalsandalloyshavedifferentcharacteristicsthatcanaffecttheeasewithwhichtheycanbemadeintodifferentshapesandthicknesses.Itisimportanttoconsidertheshapeofthefinalpreforminthealloyselectionprocess.

4.Theoperatingenvironmentofthecompletedassemblyisalsoanimportantconsiderationforalloyselection.Willitoperateinveryhighorverylowtemperatures,orbesubjectedtovibration?Ifso,youneedtoselectanalloythatwillstanduptotheseconditions.

OurApplicationEngineerswillworkwithyoutodeterminethebestalloyforyourapplication.

Dimensional Specification RecommendationsWidth/length or diameter: Typical TolerancesUp to 2.54mm (0.100”) ± 0.051mm (± 0.002”) Over 2.54mm (0.100”) ± 0.127mm (± 0.005”)Thickness:Up to 0.025mm (0.001”) ± 0.005mm (0.0002”)

0.025mm (0.001”) to 0.050mm (0.002”) ± 0.0076mm (0.0003”)> 0.050mm (0.002”) to 0.254mm (0.010”) ± 0.0127mm (0.0005”)> 0.254mm (0.010”) to 0.508mm (0.020”) ± 0.0254mm (0.0010”)> 0.508mm (0.020”) to 1.27mm (0.050”) ± 0.0635mm (0.0025”)> 1.27mm (0.050”) ± 5%Burr Tolerances (Discs, Squares & Rectangles):≤ 1.27mm (0.050”) 0.050mm (0.002”)> 1.27mm (0.050”) to 12.7mm (0.500”) 0.076mm (0.003”)> 12.7mm (0.500”) 0.127mm (0.005”)Burr Tolerances (Washers & Frames):≤ 2.54mm (0.100”) 0.076mm (0.003”)When thickness ≥ 2/3 of I.D. 0.127mm (0.005”)

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Metal Thermal Interface MaterialsSolderable Flux-Coated Preforms

Features• Eliminatestheneedformanualfluxing• Eliminatesexcessivefluxresidue• Increasesproductivity• Appliesfluxpreciselywhereitisneeded• Appliesauniformamounteverytime

IntroductionFluxCoatedPreformseliminatethecostlyproductionstepofseparatefluxingandincreasethroughputyields.FluxCoatingsforPreformsareavailableinno-cleanandrosin-basedchemistrieswithavarietyofactivitylevelstosuityoursubstratemetallizations.

Flux CoatingsIndiumCorporation’suniquecoatingprocesscancontroltheamountoffluxtotighttolerances.FluxCoatingsaremeasuredandappliedbyweightpercentage.Thecoatingsrangefrom1-3%andstandardtolerancesarecontrolledat+/-.5%.Coatingscanbeappliedtomostsizesandshapesofpreforms.

Using Flux-Coated Preforms In Soldering

Forcertainsolderingapplications,fluxcoatedpreformsmayofferthegreatestnumberofbenefitsoverothermoreconventionalformsofsolder.Forapplicationsotherthanactivedevicemanufacture,fluxcanbeincorporatedasanintegralpartofthepreformdesigntomeetcustomerneedsforthepreciseamountsofflux,easyautomation,andeliminationofcostlyseparatefluxapplications.

Ingeneral,fluxesshouldbeavoidedinactivedeviceassemblyduetothedifficultyinremovingthefluxresidueaftersoldering.Ifcareistakentoensurethejoiningsurfacesandthepreformsarethoroughlyclean,andifareducingatmosphereat350°Cisused,fluxcoatingisusuallynotnecessary.

FluxcoatedIndalloysoftsolderpreformseliminatethenecessityofmanuallyapplyingexternalliquidfluxesinoperationssuchasvaporphasesolderingofback-planewiringassembliesandcapacitormanufacture.Fluxcoatedpreformsaremanufacturedwiththeexactamountoffluxrequiredforthespecificapplication,providingahighdegreeofconsistencyfromonebondtoanother.Fluxpercentagescanbespecifiedbetween0.5%and3%byweightwithatoleranceof±0.5%.Themostpopularpercentagebeing1.0%byweight.

Indalloyfluxtypesareavailableinnon-activatedpuregumrosin(typeR),mildlyactivatedrosin(typeRMA)andfullyactivatedrosin(typeRA).RMAfluxeshaveasmallbuthighlyeffectiveamountofanactivatoraddedtoincreasefluxingactionovertheRtype.RAfluxescontainasmallamountofanaminehydrochlorideactivatorthatprovidessuperiorfluxingaction,ascomparedtoRandRMAtypefluxes.RAfluxfindsuseinsolderingassemblieswhereahighdegreeoffluxingactionisdesired,e.g.solderingtotarnishedcopperornickelplate.RSA,anenhancedversion,isalsoavailablefor

preformcoating.Thisfluxisthestrongestoftherosintypes.NC-7andNC-9fluxesarespeciallyformulatedRMAtypefluxesthat,alongwiththeRtypeflux,leavenonconductiveandnon-corrosiveresiduesthatcansafelybeleftonanassemblywithoutfearofcorrosion.However,foraestheticorvisualinspectionpurposes,thefluxresiduecanberemovedusingabipolarsolventtoremoveboththerosinportionandtheionizableactivatorportionoftheflux.Thisismostoftenaccomplishedusingvapordegreasingequipment.

Insummary,theuseofIndalloyfluxcoatedpreformscanresultinthefollowingadvantages:

1.Allfluxesusedtocoatpreforms,whenreflowedusingastandardSn63profile,passSIRtests.

2.Thepreciseamountoffluxandalloyaredeliveredtothesolderjoint.

3.Thecostlyproductionstepofseparatefluxingiseliminated.

4.Bondingisfasterbecausethefluxispositionedwhereitisrequired,nexttothesurfacestobejoined,unlikethecasewithflux-filledpreforms.

5.Becauselessfluxisused,postsoldercleaningiseasier.

6.Thefluxquantityisuniforminthicknessandconsistentinamountfrompiecetopiece.

7.Thedull,flux-coatedsurfaceisidealforIRreflow.

8.Sincethefluxonfluxcoatedpreformscontainsnosolvent,voidingistypicallylessthanwhenmanuallyapplyingliquidfluxtouncoatedpreforms.

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Solderpreformsaremanufacturedsoldershapesthatcomeinstandardformssuchassquares,rectangles,discs,washersandframes.Theycanalsobemanufacturedwithcustomgeometries.Preformsprovideconsistentpart-to-partdimensionsthatresultinconstantsoldervolumes,therebyinsuringconsistencyinsolderassembly.Becausepreformsaremadewithauniformshapeandsize,automationoftheassemblyprocesscanbeeasilyimplemented,resultinginfasterproductionandreducedcosts.

Toolingdesignchangescanincreasecostsrapidly,especiallywhenexperimentingwithmultipleshapesandsizes.A“trialanderror”approachtodeterminingthebestpreformgeometryforanapplicationthatincludessolderscontainingpreciousmetalscanalsocreateunnecessaryexpenditures.Itisbesttodoallthepreformdesignhomeworkbeforecommittingtofinaltooling.Thisapplicationnotewillexploresomesimplewaystoarriveattheoptimumpreformsizeandshapewhilereducingcosts.Theprinciplesbelowcanbeusedinconcertwithoneanother.

1)Avoid using solder alloys that contain precious metals when determining the optimum preform geometryDeterminingthebestgeometrycanbedoneusingalessexpensivealloy.Forexample,iftheapplicationcallsforAu/Snsolder,use90Pb/10Snorsomeotherlowercostalloytooptimizepreformdimensionstodeterminetherequiredsoldervolumeforthejoint.Higherleadcontainingalloysarepreferredsincethedensityofleadisclosertogoldthantin.Iftheapplicationrestrictsthe2dimensionalshapeofthepreform,varyingthethicknessisagoodwaytoarriveattheappropriatevolumeofsolderrequired.

2)Cut preforms by hand from solder ribbon or sheet when prototypingChangestotoolingdesigncanaddcostandimpacttheoveralltotalcostofpreforms.Fabricatingsmallvolumesofpreformsmanuallycanbeaneconomicmethodofarrivingattheoptimumpreformshapeandsize.

Standardalloysandmanyspecialtysolderalloyscanbepurchasedinribbonorsheetforminwidthsclosetothatofonedimensionofthepreform.Usingasharpcuttinginstrument,suchasanX-Actoknife,cuttheexperimentalshapefromtheribbonorsheet.

3)Begin evaluations using thin solder materialsIftheproperpreformthicknessisinquestion,itisbesttobeginwiththethinnestpreformpossible.Iftheappropriatevolumeisnotimmediatelyachievedwithonepreform,theycanbestacked.Multiplepreformswillflowtogetherandfunctionasone.

Forexample,afterattemptingtouseapreformthatis.002”thick,itisevidentthatthevolumeofsolderprovidedbythepreformisinsufficient.Theamountofsoldercanbedoubledbystackingtwopreforms,whichwouldequatetohavingonepreformthatis.004”thick.Thesoldervolumecanbetripled,andevenquadrupleduntilthepropervolumeisachieved.Thisallowsfortheappropriatethicknessofasingleproductionpreformtobedetermined.

4)Use the simplest preform geometry possibleEngineeringchargesforintricatedesignscancostsubstantiallymorethanlesscomplexdesigns.Designthesolderlocationssothattheycanbeadequatelybondedusingsimplepreformgeometriessuchaswashers,frames,discs,rectangles,etc.

5)Determine from the solder supplier the sizes and shapes for which tooling existsAnimportantissueinanysolderingapplicationistheresultantvolumeofsolderatthejointafterreflow.Thesizeandshapeofthepreformaregenerallysecondaryconsiderations.Oftenexistingtoolingthatyieldsslightlydifferentxandydimensionsfromtheidealsizecanbeutilizedifthethicknessofthepreformisadjustedaccordinglytoproducethesamesoldervolume.

Forexample,thedesignofanapplicationcallsforasolderpreformintheshapeofa1.2”x1.2”square.Thesoldersupplierdoesnothavetoolingforthissizebuthasexistingtoolingfora1.0”x1.0”preform.Toavoidadditionaltoolingcoststhe1.0”x1.0”sizeisselectedandthepreformthicknessincreasedtoyieldthesamesoldervolume.

Metal Thermal Interface MaterialsSuggestions for Solder Preform Design Informs

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Metal Thermal Interface MaterialsSuggestions for Solder Preform Design Informs

IntroductionInFoRMS®arepatentedfabricationsinwhichbraided,woven,orrandom-fibermetalornon-metalsubstratematerialsaresandwichedbetweenlayersofpureindiumorsolderalloy.Inthemanufacturingprocess,materialfromthesurfacelayerspassesthroughthesubstratematrixtocoldweldwherethemetalsmeetwithinthematrix.Theprocessproducesareinforcedindiumorsolderfabricationwithimprovedstrengthandhandlingcharacteristics.

Thelayersmayalsobeadheredtothesubstratewithoutcoldweldingattheinterfacesothesubstratecanflextoaccommodateshearorthermally-inducedforces.Anotheroption,wouldbetoadhereanouterindiumoralloylayertoonlyonesideofasubstrate.

Forsolderapplications,fluxmaybeincorporatedwithinthematrixorappliedasacoating.

Afterthelaminatingprocessiscomplete,partsarecutorpunchedintodiscs,washers,rectanglesandothershapestosuitspecificapplicationrequirements.Stripmaterialscanalsobeprovidedforcustomsizingbytheuser.

Product AdvantagesInformsofferdramaticallyimprovedhandlingwhencomparedtoconventionalsolderalloyorindiumsheet,foil,ribbonorlargepreformmaterials.InFORMSalsoofferincreasedtensileandcompressivestrengthviathesubstratematerialswhileretainingtheuniqueattributesoftheouterlayermetal(e.g.thesoftness,ductility,andotheradvantagesofindium).

ApplicationsInFoRMSprovideengineerswithanenhancedmaterialforthedevelopmentofnew,ortheimprovementofexisting,applications.Theycanbeusedincryogenicorvacuumseals,EMIandRFIshielding,groundstraps,stand-offs,thermalmismatchdevicesorbackplaneassemblywashers.Whileanumberofmetalsmaybeused,indiumshouldbeconsideredinmanyapplicationsbecauseofitsuniqueattributes.Forexample,Indiumreadilywetsglass,quartz,andglazed

ceramics.Whencomparedtoconventionalsolders,indium-basedsolderssignificantlyreducescavengingandleachingofgoldandotherpreciousmetals.

Substrates and outer Layer MetalsInFoRMScanbeproducedfromawiderangeofmetalandnon-metalsubstratesdependingontheneedsoftheapplication.InFoRMShavebeensuccessfullyproducedusingtinplatedcoppershieldingmesh,stainlesssteelmesh,andevenwovenandrandom-fiberfiberglasscloth.PleasecontactourTechnicalSupportEngineersifyouwouldlikeustoworkwithyoutodevelopsamplesforexperimentation,includingspecialsubstratematerials,layerthicknesses,orouterlayermetallizations.

Inapplicationswherethemetalmeetsinthesubstratematrix,metalsusedonouterlayersmaybedissimilaraslongastheyarecompatiblewitheachother.Wheretheapplicationdoesnotrequirecoldweldingoftheouterlayers,thelayersmayalsobedissimilar.Ineithercase,compatibilitywiththesubstratematerialmustbeconsideredinapplicationsdevelopment.Mostcompatibilityissuesaredocumentedinsoldertechnicalguides.However,ifinquestion,it’salwaysagoodideatocontactIndiumCorporationforadvice.Whensolderalloysarespecified,publishedtemperatureguidelinesareapplicable.

Dimensional SpecificationsInFoRMSareproducedinsheetformandcanbecutorpunchedintolargeuniqueshapesforapplicationssuchascryogenicorvacuumseals,orintosmallpreformsfortaskssuchascomponentassembly.Dimensionaltolerancescanbeheldtothosenormallyspecifiedforstandardsolderpreforms,butmayvarydependingonthepartsize,thickness,substrate,andouterlayermaterials.Pleasecontactusifyouhavespecialrequirements.

SummaryInFoRMSaddhandlingcapabilitytosoftandductileindiumandsolderalloys.Theyalsostrengthenandyetretain,theuniqueattributesofthemetalsselectedfortheouterlayers.InFoRMSoffercountlessopportunitiesforsolvingdifficultapplicationproblems.

Reinforced Indium and Solder Alloy Fabrications

Tape and Reel PackagingFlexibilityTape and Reelpocketsareavailableinawiderangeofsizestoaccommodatevariouspreformshapesandsizes.

Shelf LifeTheshelflifeofsolderpreformsisdependentonthealloycomposition.Pb-freealloys,andalloyswithleadcontentoflessthan70%,haveashelflifeof1-yearfromthedateofmanufacture(DOM).Alloyswithleadcontent>70%haveashelflifeof6-monthsfromtheDOM.

Technical SupportIndiumCorporation’sinternationallyexperiencedengineersprovidein-depthtechnicalassistancetoourcustomers.ThoroughlyknowledgeableinallfacetsofMaterialScienceasitappliestotheelectronicsandsemiconductorsectors,TechnicalSupportEngineersprovideexpertadviceinsolderproperties,alloycompatibilityandselectionofsolderpreforms,wire,ribbonandpaste.IndiumCorporationTechnicalSupportengineersprovideRapidResponsetoalltechnicalinquiries.

IntroductionSolderPreformsareusedinavarietyofapplicationsthatrequirepreciseamountsofsolder.Dimensionscanbeheldtotighttolerancestoassurevolumeaccuracy.Solderpreformsareavailableinavarietyofalloys,includingindium,gold,tin,lead,andmanyothers.

SolderPreformscomeinstandardshapes,suchassquares,rectangles,washers,anddiscs.Typicalsizesrangefrom0.010”(.254mm)upto2”(50.8mm).Smallerandlargersizes,aswellascustomshapes,arealsoavailable.

Tape and Reelpackagingofpreformsallowsforeasieruseinhighvolumeandautomatedmanufacturingenvironments.

ApplicationsTape and Reel Preformsofferadvantagesoverloose-packedpreformsinmanyapplications.Somecommonexamplesare:

•Automation–Tape and Reel PreformsallowforeasyusewithpickandplaceequipmentinSMTlines.Theycanbepreciselyplacedasfastasyourequipmentwillallow.

•SolderFortification–TherearecertaininstancesinSMTapplicationswheresimplyprintingpastedoesnotprovidesufficientsoldervolume.Ratherthanresorttostepstencilingordispensing,aplacedpreformcanbemoreefficientbygivingyouprecise,repeatablesoldervolume.

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Benefits • Maintainsstandoff• Bridgesgaps• Addsstrengthtosolderjoints

IntroductionClad Solder Preformsaremanufacturedshapesthatdeliverapreciseamountofsolderwhilemaintainingand/orbridgingaparticulargap.Theyconsistofacopperlayerthatiscladononeorbothsideswithaspecifiedthicknessofsolder.Dimensionscanbeheldtotighttolerancestoassurevolumeaccuracy.Cladsolderpreformscomeinstandardshapesandsizessuchassquares,rectangles,washers,framesanddiscs.Typicalsizesrangefrom.254mmupto50.8mm.Smallerandlargersizes,aswellascustomshapes,arealsoavailable.

Alloys/Materials Typicalalloysinclude:• Sn62/Sn63• 96.5Sn/3.5Ag• Sn10• Otheralloysareavailableuponrequest.

ThecorematerialisOFHCCopper:• AnnealedPerASTM-B152• Fscale• TensileStrength35,000psimax.• Othercoppersareavailableuponrequest.

PackagingClad Solder Preformsarepackagedinformatssimilartostandardpreformsandtakeintoconsiderationthesizeandstrengthofthepreform.Commonpackingmethodsincludejars,boxes(stackorlayerpack)andtape&reel.Mostpackagescanbebackfilledwithargonuponrequest.

Whenpossible,wesuggestfillingeachpackagewiththequantityofcladsolderpreformsthatwillbeconsumedinoneshift.

Storage and Handling ProceduresClad Solder Preformsshouldbekeptintheirunopenedcontainerinacooldryplaceuntiltimeofuse,preferablyinanitrogendrybox.Afteropening,anyunusedpreformsshouldbestoredinthesesameconditions.

SafetyEating,drinkingandsmokingshouldbeavoidedwhilehandlingpreforms.Handsshouldbewashedimmediatelyfollowinguse.Ifpossible,preformsshouldbehandledwithprotectiveglovesorfingercots.

Applications• HeatSinkAttach• PinSoldering• 3DSoldering• JumperBridges• Connectors

Andothersolderingapplicationswherethefollowingpropertiesaredesired:•Strength•WearResistance•Formability•ElectricalProperties•ThermalProperties

Compatible Products • Clad Solder Preformscanbefluxcoatedwithanyofourstandardpreformfluxcoatings.

• IndiumCorporation’sliquidfluxesandTACfluxes.

MetalThermalInterfaceMaterials FluxesClad Solder Preforms Rosin/Resin Based Liquid Soldering Fluxes

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Flux RemovalSincethepostsolderresiduesoftypesRandRMAfluxesareconsiderednon-corrosive,non-conductiveandnon-hydroscopic,fluxremovalisnotusuallynecessary.Ifcleaningisdesiredthisisbestaccomplishedwithacommerciallyavailablefluxresidueremover.

BestpracticeistoalwaysremoveRAresiduesinelectronicsapplications.

Standard PackagingTheseliquidsolderingfluxesarepackagedin2differentsizeplasticcontainers:•1U.S.pint(0.473liter)•1U.S.gallon(3.785liter)

MetalThermalInterfaceMaterials FluxesClad Solder Preforms Rosin/Resin Based Liquid Soldering Fluxes

Features•SuitableforPin-GridArrayandstandardBallGridArrayapplications

•Excellentsolderabilitytoallcommonsurfacemetallizations

•No-cleanresidue•Canbeusedforprinting,dipping,andpintransferdeposition

•OffershighyieldsinBGAbumpingprocess•SuitableforbothPb-FreeorSn/Pbapplications

IntroductionBall Attach Flux NC-506isalowviscositythixotropicno-cleanfluxdesignedforuseinballattachmenttosubstrates(BGAmanufacturing).Itisespeciallyusefulinapplicationsrequiringsolderingtosurfacefinisheswithtenaciousoxides,suchasnickel.Itcanalsobeusedwhereverano-cleanballattachfluxisneeded,andissuitableforavarietyofdifferentdepositionmethods.

NC-506 Flux

Properties Value Test MethodFlux type Classification: ROL1 J-STD-004 (IPC-TM-650: 2.3.32 and 2.3.33)Typical Viscosity: 320kcps Brookfield HB DVII+-CP (5rpm)SIR (ohms, post cleaning): Pass (>109 after 7 days @ J-STD-004 (IPC-TM-650: 85ºC & 85% RH) 2.6.3.3 IPC-B-24Typical Acid Value: 103mg KOH/g Titration Typical Tack Strength: 250g J-STD-005 (IPC-TM-650: 2.4.44)Shelf Life: 6 months (-20°C to +5°C)* Viscosity change/ microscope examination All information is for reference only. Not to be used as incoming

product specifications.

All information is for reference only. Not to be used as incoming product specifications.

Flux #5R #5RMA #5RARosin/Resin Bas Heat Stabilized Resin Heat Stabilized Resin Heat Stabilized ResinSolderingTemperature Range

125ºC - 350ºC 125ºC - 350ºC 125ºC - 350ºC

MetallizationTo Be Soldered

Au, Ag, Pt, Pd, Clean Cu

Au, Ag, Pt, Pd,Clean Cu, Sn, Solder Plate

Ni, Rh, Cd, Brass, Bronze BeCu, Pb, Oxidized Cu

Activation None Added Mildly Activated Fully ActivatedSolids Content 47% 46% 44%Water Resistivity Extract (ohm-cm)

>100,000 >100,000 >50,000

Specific Gravity .90 .91 .88Boiling Point 84°C 84°C 84°CFlash Point 11°C 11°C 11°CIPN 84072 84032 84039

Thinner #8300 (Part Number 84041) - all fluxes

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Benefits• Excellentcleanability,residuecanberemovedwithroomtemperaturewater

• Canbeusedforprinting,dipping,andpintransferdeposition

• OffershighyieldsinBGAbumpingprocess• Excellentsolderability• Wideprocesswindow• SuitableforSn/Pb,Pb-Free,andhighlead-containingapplications

• DesignedforFlip-Chipapplications

IntroductionWS-366 Interconnect Fluxisahighviscositypaste-typefluxdesignedforuseinBGAbumpingandboardlevelattachment.Itcanalsobeusedwhereverawater-solublefluxwithexcellentcleanabilityisdesired.

All information is for reference only. Not to be used as incoming product specifications.

Fluxless SolderingSomeapplicationsareverysensitivetotheuseofafluxduetothepostreflowresiduethatmaybepresent.Also,fluxmaybeaprobleminavacuumenvironmentorinanapplicationinwhichitmustbefreeofcorrosiveorvolatilematerials.

Ifgoldisusedfortheoutermetalizationonthepartstobejoined,acceptablewettingmaybepossiblewithouttheuseofaflux.Ifthisisnotpossible,areducingatmospheremaybeusedtoremovetheoxidesandresultinsufficientwetting.Belowaresuggestionsandhelpfulhintsforchoosingareducingatmospherethatfitsyourapplication.

•Commonreducingatmospheresare:88%nitrogen,12%hydrogen90%nitrogen,10%hydrogen95%nitrogen,5%hydrogen100%hydrogen

•Thehigherthereflowtemperaturethemoreeffectivetheoxidationremovalusingareducingatmosphere.Areflowtemperaturethatis350°Candaboveisthebestforoxideremoval.

•Nitrogenorargonissometimesusedinfluxlesssolderingbecauseitpreventstheformationofoxidesduringreflow.However,thesegasesdonotremovepreexistingoxidesonthemetalization,onlythehydrogencandothat.

Fluxlesssolderingisalsousedwhenjoiningthetwosubstratestogetherwherefluxresiduewouldbedetrimentaltotheoperationofthefinalproduct.Forexample,voidingduetofluxentrapmentcanresultinpoorperformancebecauseofredudedelectricalorthermalconductivity.

Inanapplicationwhereareducingatmosphereisnotpractical,twoormoremetalizationscanbejoinedusingfluxintheinitialpre-coatingofthesubstrates.Afterpre-coatingiscomplete,thefluxresiduecanberemovedusinganappropriatesolvent.Thecleanedpartscanthenbeassembledwithoutafluxandreflowedafinaltimetojointhem.Thismethodisespeciallyeffectivewhenfairlylargepiecesneedtobejoinedandfluxentrapmentcannotbetolerated.

Fluxes MetalThermalInterfaceMaterialsWS-366 Interconnect Flux Bonding Non-Metallic Materials

PropertiesFlux type Classification: H1Color: Amber to brownStencil Life: >8 hours at room temperatureShelf Life: 3 months at 0 to +30°CSIR (ohms, post cleaning): Pass (>109 after 7 days @ 85ºC & 85% RH) Typical Viscosity: Brookfield: 425 kcps at 5rpm Halide Content: <3% Cl equivalent Acid Value: 30-50 Tack Strength: 100-400g

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ApplicationAuniquepropertyofindiumisthatitwillwetandbondtocertainnon-metallicssuchasglass,glazedceramics,mica,quartzandvariousmetallicoxides.

Metal/Alloy SelectionIndalloy#4(100%indium)andIndalloy#1E(52In48Sn)exhibitthebestwettingqualityonnon-metallics.Indalloy#3(90In10Ag)andIndalloy#290(97In3Ag)exhibitslightlylowerwettability,buthigherstrength,duetothehardeningeffectofthesilverpresent.

Surface PreparationBeforebonding,thoroughlycleanthenon-metallicsubstratewithastrongalkalinecleaner.Rinsewithdistilledwaterandrinseagainwithelectronicsgradeorganicsolvent,suchasacetone.Inthecaseofglass,quartzorglazedceramics,adhesionisenhancedbyheatingthematerialtoabout350°C,thencoolingtoabout200°C.

Bonding ProcedureApplyindiumtotheheatednon-metallicusinganindium-platednickelfeltapplicator.Rubgentlyuntilthenon-metalliciscoatedwithathinfilmofindium.

Tobondtwonon-metallicsubstratestogether,precoateachsurfacewithindiumasdescribedabove.Bringthetwoprecoatedsubstratesincontactwitheachotherandreflowat20-30°Covertheliquidustemperatureofthesolderusedtoprecoat.

Tobondanon-metallicsubstratetoametallicsubstrate,precoatthenon-metallicsurfacewithindiumasdescribedabove.Precoatthemetallicsurfacewiththesameindiumalloyasusedonthenon-metallicsurface,usinganappropriateflux.Completelyremovethefluxresidue.Bringthetwoprecoatedsurfacesincontactwitheachotherandreflowat20-30°Covertheliquidustemperatureofthesolderusedtoprecoat.

Inmostcases,ultrasonicenergy,likethatgeneratedbyanultrasonicsolderingironorpot,iseffectiveinpromotingwettingofthesurface.Bondstrengthsof400-700PSIaretypicalofthistechnique.

Thefollowinglistoffouralloysarerecommendedforbondingnon-metallicmaterials.Themeltingtemperaturesandsomeofthepropertiesoftheindividualalloysarealsolisted.

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otesFluxes MetalThermalInterfaceMaterialsWS-366 Interconnect Flux Bonding Non-Metallic Materials

Using Indium and High Indium Alloys

E= Eutectic, MP= Melting Point

IndalloyNumber Liquidus Solidus

TensileStrength

PSI

ElectricalConductivity% of IACS

ThermalCoefficient

of Expansionµ in/in/°C@20°C

ThermalConductivity

W/m•K@85°C

Composition

# 1E 118°C E 1720 11.7 20 34 52In 48Sn

# 3 237°C 143°C 1650 22.1 15 67 90In 10Ag

# 4 157°C MP 273 24.0 29 86 100In

# 290 143°C E 800 23.0 22 73 97In 3Ag

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Contactareainathermalinterfaceisakeyconsideration,especiallyinreal-worldapplicationsinvolvingsurfacesthatarenotideal.

Typicalflip-chipdiesurfacesonlaminatepackagescanvary.001”/.4”(1cm),andthesameistruewithliddedcomponents.Mostofthisvariationoccursbecauseofstressesimpartedduringtheattachmentofthedieorpackage.Ontheheatsinkside,manufacturingmethodsvary–asdoessurfaceplanarity.Thefirstpartofplanningthedesiredthicknessofyourthermalinterfacematerial(TIM)istodetermineastack-updimensionoftolerances.Takeintoaccountmaximumsurfacevariationsatambientconditionsandduringoperationaltemperatures(includingburn-in)tocompensatefortheleastidealassemblythatispossiblefromyourprocedure.

Assemblycanalsoincreasethegapbetweentheheatgeneratingcomponentandthelidorheatsink.Forinstance,ona1cmdie,1°ofmisalignmentcreatesagapof.007”(RefertoFig.#2).Misalignmentneedstobefilledwithathermalinterfacematerialforproperconduction.

Finally,itisimportanttomakesurethereissomeTIMbetweenthetwointerfacedsurfacesattheclosestpoint.Itmaybenecessarytoadd.001”ofsTIMthicknesstothepreviouslyestimatedstack-upthickness.Evenanideallyflat,alignedinterfaceshouldhavea.001”sTIMbondline.

Suggested Preform Thickness(1cm x 1cm interface)

For Worst Case Bondline Thickness

Metal Thermal Interface MaterialsDesigning a sTIM Etching Indium to Remove Oxides

Fig.#1Heatsink/BoardWarpFig. Fig.#2CompoundWarp/Alignment

Lessroughness,lesscurvature,smallerareaandreducedCTEwillenableathinnerbondline.

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Die Curvature(µm) Lid Curvature (µm) Misalignment (µm) Suggested Thickness (µm)

10 10 10 60-90

10 10 30 80-100

10 30 30 90-110

30 10 30 90-110

10 10 50 100-130

10 30 50 110-140

30 10 50 110-140

30 50 80 180-200

50 50 80 200-230

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Indium Cold Welding

Theformationofmetaloxidesonindiumisself-passivating.Athicknessof80-100Angstromsofoxideisallthatwillformonthesurface.Priortousingindiuminasealingorcoldweldingapplication,itisrecommendedthatthisoxidelayerberemoved.Hereistherecommendedprocedureforoxideremoval:

1.Degreasetheindiumwithanorganicsolvent,suchasacetone,toremoveanyorganiccontaminantsthatmaybeonthesurface.

2.Mildlyetchtheindiumsurfacesinasolutionof5-10%hydrochloricacid(byvolume)atroomtemperaturefor1to5minutes,dependingonoxidethickness,untilsurfaceappearsbright.Thiswillremovethe80-100Angstromsofoxidethatformonthesurface.

3.ThoroughlyrinsetwiceinDIwater.

4.Rinseoffthewaterwithacetone(preferred)orisopropylalcohol.

5.Blow-drywithdrynitrogen.

Note:Becausethisprocedureslightlyetchesthemetallicsurface,exposingalargersurfaceareatooxidation,onlytheindiumthatisgoingtobeusedimmediatelyshouldbecleanedbythisprocedure.Returnanyunused,etchedindiumtostorageundernitrogenorargon.

Indiumhastheuniqueabilitytocoldweldtoitself.Ifthesurfaceshavebeencoatedwithindium(minimum0.002”-0.003”),theycanbejoinedbyfollowingthisprocedure:

1.Degreasetheindiumwithanorganicsolvent,suchasacetone,toremoveanyorganiccontaminantsthatmaybeonthesurface.

2.Mildlyetchtheindiumsurfacesinasolutionof5-10%hydrochloricacid(byvolume)atroomtemperaturefor1to5minutes,dependingonoxidethickness,untilsurfaceappearsbright.Thiswillremovethe80-100Angstromsofoxidethatformonthesurface.[Indiumisself-passivatingandwillformanoxidelayerthatisonly80-100Angstromsthick.Theoxide,onceremoved,willreformtothe30-40Angstromslevelimmediatelyandtothe80-100Angstromslevelinabout3days.Thisoxidelayerreducesindium’sabilitytocoldweld.]

3.ThoroughlyrinsetwiceinDIwater.

4.Rinseoffthewaterwithacetone(preferred)orisopropylalcohol.

5.Blow-drywithdrynitrogen.

6.Amildpressureisallthatisusuallyrequiredtojointheindiumsurfacestogether.

7.Usecautiontoproperlyaligntheindiumbeforejoining,astheywillnoteasilyseparatewithoutdamagingthejoint.Theywillsticklikecontactcement.

Pure indium ribbon with normal oxide layer of 80-100 Å (formed at room temperature in ambient conditions).

Indium ribbon being etched in the hydrochloric acid solution for 1 minute to remove oxide layer.

Etched indium ribbon wound back on itself and cold-welded to form a loop.

Metal Thermal Interface MaterialsDesigning a sTIM Etching Indium to Remove Oxides

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Metal Thermal Interface Materials

MaterialIndalloy Number

Thermal Conductivity

W/m•K at 300K


W/m•K at 85C

Liquidus (C) MP/E

Solidus (C)

Diamond 1300-2400 SiC 611 Ag 429 Cu 401 Au100 200 318 1064 MP Au 317 Beo 250 Al 240 AlN 200 W 180 Zn 116 Ni 91 Fe 84-90 In100 4 82 86 156.7 MP In97 Ag3 290 73 143.3 E 143.3Sn100 128 73 232 MP Pd 72 Pt 72 In90Ag10 67 In90 Ag10 3 67 237 143Sn 66 Sn91 Zn9 201 61 199 E 199Au80 Sn20 182 57 57 280 E 280Sn77.2 In20 Ag2.8 227 54 187 175

Sn62.5 Pb36.1 Ag1.4

104 50 179 E 179

Sn63 Pb37 106 50.9 50 183 E 183Sn60 Pb40 109 49.8 49 191 183Sn62 Pb36 Ag2 49

Sn50 Pb50 116 46.7 48 212 183Sn70 Pb18 In12 9 45 167 154

Pb60 Sn40 130 44 238 183Au88 Ge12 183 44 44 356 E 356Sn40 Pb60 43.6 In80 Pb15 Ag5 2 43 154 149

Pb70 Sn30 141 40.5 41 257 183In70 Pb30 204 38 175 165Pb80 Sn20 149 37.4 37 280 183Pb100 170 35 35 327 MP In52 Sn48 1E 34 118 E 118In50 Sn50 1 34 125 118

Sn96.5 Ag3.5 121 33 33 221 E 221

Sn60 Bi40 281-338 30 170 138

MaterialIndalloy Number


W/m•K at 300K


W/m•K at 85C

Liquidus (C) MP/E

Solidus (C)

In60 Pb40 205 29 181 173Sn95 Sb5 133 28 28 240 235Pb88 Sn10 Ag2 228 27 290 267

Au96.76 Si3.24 184 27 363 E 363

Pb90 Ag5 Sn5 155 25 292 MP

Pb92.86 In4.76 Ag2.38

6 25 300 MP

Pb90 Sn10 159 35.8 25 302 275Pb89.5 Sn10.5 242 25 302 275

Pb90 In5 Ag5 12 25 310 290

Pb92.5 In5 Ag2.5 164 25 310 300

Sb 24 Pb37.5 Sn37.5 In25 5 23 181 134

Pb97.5 Ag1.5 Sn1 165 23 309 E 309

Pb95 Sn5 171 35.2 23 312 308Pb94.5 Ag5.5 229 23 365 304

In50 Pb50 7 35 22 210 184Pb95 In5 11 21 313 300Bi58 Sn42 281 19 138.3 E 138.3Pb60 In40 206 19 231 197Pb75 In25 10 18 260 240Pb81 In19 150 17 275 260Alloy 42 15.6 Bi52 Pb30 Sn18 39 13 96 E 96

Boron Nitride filled Silicone

6

Bi55.5 Pb44.5 255 4 124 E 124

Solver Filled Phase Change

3.0 - 8

Ag - Filled Die Attach 1.3 - 5

Molding Compounds 0.6 - 0.7

BT Epoxy 0.19 FR-4 0.11 Air 0.03

Typical Indium ApplicationsIndium,the49thelement,wasdiscoveredinGermanyin1863.In1934,IndiumCorporationofAmericawasthefirsttobegincommercialdevelopmentofindium,andisstilltheleadingrefiner,fabricator,andmarketerofthisversatilesilver-whitemetal.Indiumisusedinawidevarietyofapplications,basedonitsuniqueattributes.

SolderingWhenindiumisincludedinsoldercompositions,manyadvantagesarerealized.Comparedtoconventionaltin-leadsolders,indiumalloysexhibitlowercrackpropagationandimprovedresistancetothermalfatigue.Indiumwillreducegoldscavengingthatcanoccurwith

tin-basedsolderongoldorgold-platedparts.Itsductilitywillallowsomematerialswithdifferentcoefficientsofthermalexpansiontobejoinedtogether.Inspiteofthemetal’ssoftness,itcanstrengthenmaterialsitisalloyedwith.

BondingTheuniquepropertiesofindiummakeitanidealbondingmaterial,especiallywhenbondingnon-metalssuchasquartz,glass,andglazedceramics.Indiumcanalsobecoldweldedtoitself.Iteasilydeformsunderpressureandwillfillvoidsbetweentwosurfaces,evenatcryogenictemperatures.

Low-Temperature AlloysIndiumisalsothebasisformanylowmeltingpointfusiblealloys.Thesealloysareoftenusedtoholdproducts,suchaseyeglasslensesorturbineblades,whiletheproductsarebeingworkedon.Thenthealloycanberemovedwithminimalheat,keepingtheproductfrombeingdamaged.Indiumisalsousedwithgalliumtocreatealloysthatareliquidatroomtemperature.

Thin FilmsThinfilmsofindium-tinoxide(ITO)onclearglassorplasticfunctionastransparentelectricalconductorsand/

orinfraredreflectors.TypicalusesofthinfilmsofITOincludeLCDflatpaneldisplays,touchscreenCRT’s,ELlampsanddisplays,EMIshields,solarpanelsandenergyefficientwindows.AircraftandautomobilewindshieldsarecoatedwithITOfordemistinganddeicing.Otherindiumchemicalsareusedinalkalinebatteries,replacingtoxicmercurycompounds.

High-Purity IndiumHigh-purityindium(99.9999and99.99999)isusedinIII-Vcompoundsemiconductorssuchaslaserdiodes.

Tech

nical Sp

ecificatio

ns

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Metal Thermal Interface Materials

Indium,the49thelement,wasdiscoveredinGermanyin1863.In1934,IndiumCorporationofAmericawasthefirsttobegincommercialdevelopmentofindium,andisstilltheleadingrefiner,fabricator,andmarketerofthisversatilesilver-whitemetal.Indiumisusedinawidevarietyofapplications,basedonitsuniqueattributes.

SolderingWhenindiumisincludedinsoldercompositions,manyadvantagesarerealized.Comparedtoconventionaltin-leadsolders,indiumalloysexhibitlowercrackpropagationandimprovedresistancetothermalfatigue.Indiumwillreducegoldscavengingthatcanoccurwith

tin-basedsolderongoldorgold-platedparts.Itsductilitywillallowsomematerialswithdifferentcoefficientsofthermalexpansiontobejoinedtogether.Inspiteofthemetal’ssoftness,itcanstrengthenmaterialsitisalloyedwith.

BondingTheuniquepropertiesofindiummakeitanidealbondingmaterial,especiallywhenbondingnon-metalssuchasquartz,glass,andglazedceramics.Indiumcanalsobecoldweldedtoitself.Iteasilydeformsunderpressureandwillfillvoidsbetweentwosurfaces,evenatcryogenictemperatures.

Low-Temperature AlloysIndiumisalsothebasisformanylowmeltingpointfusiblealloys.Thesealloysareoftenusedtoholdproducts,suchaseyeglasslensesorturbineblades,whiletheproductsarebeingworkedon.Thenthealloycanberemovedwithminimalheat,keepingtheproductfrombeingdamaged.Indiumisalsousedwithgalliumtocreatealloysthatareliquidatroomtemperature.

Thin FilmsThinfilmsofindium-tinoxide(ITO)onclearglassorplasticfunctionastransparentelectricalconductorsand/

orinfraredreflectors.TypicalusesofthinfilmsofITOincludeLCDflatpaneldisplays,touchscreenCRT’s,ELlampsanddisplays,EMIshields,solarpanelsandenergyefficientwindows.AircraftandautomobilewindshieldsarecoatedwithITOfordemistinganddeicing.Otherindiumchemicalsareusedinalkalinebatteries,replacingtoxicmercurycompounds.

High-Purity IndiumHigh-purityindium(99.9999and99.99999)isusedinIII-Vcompoundsemiconductorssuchaslaserdiodes.

Phy

sical Co

nstan

ts

StructureFacecenteredtetragonalat25°C: a=0.32525nmandc=0.49465nm

Mass CharacteristicsAtomicweight: 114.82

Density:

°C gm/cc 20 7.30 164 7.026 194 7.001 228 6.974 271 6.939 300 6.916Volumechangeonfreezing,2.5%contraction

Thermal PropertiesMeltingpoint: 156.6°CBoilingpoint: 2080°CCoefficientofthermalexpansion: Linear,24.8µm/m•Kat20°C

Specificheat:

°C J/kg•K 25 233 127 252 156.63 (solid) 264 156.63 (liquid) 257 227 256 327 255 427 254Latentheatoffusion: 28.47kJ/kgLatentheatofvaporization: 1959.42kJ/kgThermalconductivity: 83.7W/m•Kat0°C

Vaporpressure:

°C kPa 1215 0.1013 1421 1.013 1693 10.13 2080 101.3

Electrical PropertiesElectricalresistivity:

°C nΩ-m 3.38 K — Super conducting 20 84 154 291 181 301 222 319 280 348

Electrochemicalequivalent: Valence3,396.4µg/CElectrodepotential: In0gIn3++3e,0.38VElectronegativity: 1.7Pauling’s

Magnetic PropertiesMagneticsusceptibility,Volumetric:7.0x10-6mks

Nuclear PropertiesNaturalisotopedistribution:

Mass Number % 113•115 4.3 115 95.7

ThermalneutroncrosssectionFor2.2km/sneutrons: absorption,190±10b; scattering,2.2±0.5bValencesshown: 3also2and1Atomicradius/Goldschmidt: 0.157nmAtomicnumber: 49Photoelectricworkfunction: 4.12eVElectronicstructure: Kr4d105s25p1Firstionizationenergy: 133k-cal/g-mole

Mechanical PropertiesTensilestrength:

K MPa 295 1.6 76 15.0 4 31.9

Compressivestrength: 2.14MPaHardness: 0.9HBElasticmodulusat20°C: 12.74GPaintensionPoisson’sat20°C: 0.4498Bulkmodulus: 35.3GPaTensilemodulus: 10.6GPa

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TechnicalSupport

Technical Support—When You Need It. Youhavechallenges,opportunities,andnewprocessestoaddress.Indium’stechnicalexpertiseisavailableinseveralforms:

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Indium’s Process Simulation Lab providesApplicationsEngineerswiththetoolstoworkwithyouandindustrypartnersondesignedexperimentstofullycharacterizeSMTassemblymaterialsandtheiruseinleading-edgetechnologyapplications,including:

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ConfidentialityIndiumCorporationrecognizestheimportanceofconfidentialityinthedesignofsolutions.Asatrustedpartner,ourengineerswillworkwithyoutohelpyoufindtherightsolutionforyourassemblyproblems.Wecanhelpyoufindtherightalloyforperformanceandthebestsolderformforeaseofassembly.

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Singapore

Clinton,NYUSA

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MiltonKeynes,UK

Utica,NYUSA

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Clinton,NYUSA

Chicago,ILUSA

Suzhou,PRC

Chicago, USA ★★★★

★★

Clinton, NY, USA

Milton Keynes, UK

★★★

★

Suzhou, China

Liuzhou, ChinaShenzhen, China

Singapore

Torino, Italy

Utica, NY, USA

LocationsWorldwide

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www.indium.com [email protected]

ASIA: Singapore: +65 6268 8678 CHINA: Suzhou, Shenzhen, Liuzhou: +86 (0)512 628 34900EUROPE: Milton Keynes, Torino: +44 (0) 1908 580400USA: Utica, Clinton, Chicago: +1 315 853 4900

Metal Thermal Interface Materials€¦ · Metal Thermal Interface Materials Introduction Liquid Indalloy® Alloys Liquid at Room Temperature Introduction Several very low melting

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