Magnetron Sputtering of metal oxides - VACUUM … Optics.pdf · Plasma Assisted Reactive Magnetron Sputtering of High Performance Interference Filters A. Zöller, H. Hagedorn, W.

Plasma Assisted Reactive Magnetron Sputtering of High Performance Interference Filters

A. Zöller, H. Hagedorn, W. Lehnert, J. Pistner, M. Scherer,

Alzenau

2Photonex 2012; Plasma Assisted Reactive Magnetron Sputtering of High Performance Interference Filters

Outline

� Plasma Assisted Reactive Magnetron Sputtering (PARMS)

� System layout

� Material properties

� Typical interference filter application

� UV coatings

� Defect investigation

� LIDT on HR mirrors

� Conclusion


Plasma Assisted Reactive Magnetron Sputtering

Load lock valve

Dual magnetronProcess module

Turn table

Substrate heater

Plasma source

Substrate



Ar+e-

Magnetron 1

MF Power supply ~

Magnetron 2

Cathode

AnodeAnode

Cathode

Magnetron 2 Magnetron 1

Vt

Plasma stabilization by MF Dual Magnetron Sputtering


System layout

� HELIOS 400 / 800

• 100mm

- 16 substrate carrier

- useful area 12 x 78cm²

= 0,12m²

• 200mm- 12 substrate carrier

- useful area 12 x 314cm²

= 0,38m²


Substrate handling

HELIOS single substrate load lock


Substrate handling

HELIOS substrate transfer


Substrate handling

HELIOS substrate transfer


Direct optical monitoring

■ Intermittent direct on-substrate monitoring

Load Lock Valve


Coating materials

�� Low intrinsic compressive coating stress

0,33- 1001,48SiO2

0,5-1802,075HfO2

0,5-702,13ZrO2

0,6- 902,166Ta2O5

0,55- 1502,365Nb2O5

0,4- 1151,67Al2O3

0,45- 3001,48SiO2

Deposition rate[nm/s]

Film stress [MPa]

Ref. index n@ 550nm

Material



Helios magnetron sputtering system with direct monitoring

Coating materials: Nb2O5 / SiO2

Short wave pass filter

OD > 7 @ 750nm-1100nm



0

10

20

30

40

50

60

70

80

90

100

200 300 400 500 600 700 800 900 1000 1100 1200

Wavelength (nm)

Tra

ns

mit

tan

ce

(%

)

Theory_Front+Back

090609-2-4-F+B_P2

090609-2-4-F+B_P3

090609-2-4-F+B_P4

090615-B+F_P9

090615-B+F_P11

� Band pass filter with broad blocking range OD6

Design

Front and backside

coating

H = Nb2O5

L = SiO2

Total layer number

94 / 104

Total thickness

9,4µm / 10.4µm



11-Cavity Bandpass Filter Ta (50% BW=30nm)


Optical Performance of the monitor glass (first run)

(w/o backside AR coating)Coating materials: Ta2O5 / SiO2

0

10

20

30

40

50

60

70

80

90

100

410 430 450 470 490 510

Wavelength (nm)

Tra

nsm

itta

nce

(%

)

Theory

OMS in chamber



13-Cavity Bandpass Filter for life science applications


0,5 dB (89%) BW– 47,7 nm

3dB (50%) BW – 48,0 nm

10dB (10%) BW – 49,2 nm

30dB (0,1%) BW – 53 nm

steepness – >50dB/nm

Highest peak - 0,3dB (95%)w/o backside AR

-40

-35

-30

-25

-20

-15

-10

-5

0

400 420 440 460 480 500 520 540

Wavelength (nm)

Tra

ns

mit

an

ce

(d

B)

1st run

2nd run

Coating materials: Nb2O5 / SiO2

Optical Performance of the monitor glass (w/o backside AR coating)



1-Cavity NBP Filter with Ta2O5/SiO2

Magnetron sputtering with direct monitoring

Optical Performance of the monitor glass (w/o backside AR-coating)

Highest peak – 0,2 dB

3dB (50%) BW – 2,1 nm

Substrates 16

Useful area @ Uniformity <+-0,2%

Diameter 60- 80mm

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1050 1052 1054 1056 1058 1060 1062 1064 1066 1068 1070 1072 1074 1076 1078 1080

Wavelength / nm

Tra

nsm

itta

nce

/ d

B

Absorption:

Single Layer 4 λλλλ /4@1064nm

Ta2O5 < 4ppmSiO2 < 3ppm



Single side coating

H = Nb2O5

L = SiO2

Total layer number

198

Total thickness

20µm

Batch time

app. 13h

4-fold-notch filter, AOI=10°

0

10

20

30

40

50

60

70

80

90

100

420 460 500 540 580 620 660 700 740

Wavelength [nm]

Tra

nsm

itta

nce [

%]

Theory

Pos 3

Pos 4

Pos 5

Pos 7

Pos 9

Pos 10

Pos 11

Spec. Tavg

� Multi notch filter


UV- and VIS Filter Coatings by PARMS

Dispersion n & k of optimized HfO2, ZrO2, and Ta2O5

2

2.05

2.1

2.15

2.2

2.25

2.3

2.35

2.4

2.45

2.5

200 250 300 350 400 450 500 550 600

Wavelength (nm)

Refr

acti

ve I

nd

ex n

0.0E+00

1.0E-04

2.0E-04

3.0E-04

4.0E-04

5.0E-04

6.0E-04

7.0E-04

8.0E-04

9.0E-04

1.0E-03

Exti

ncti

on

k

n Ta2O5 n ZrO2 n HfO2

k Ta2O5 k ZrO2 k HfO2


UV- and VIS Filter Coatings by PARMS

0,5-170λ λ λ λ ≥ 2502,075HfO2

0,5-70λ λ λ λ ≥ 2802,130ZrO2

0,6-90λ λ λ λ ≥ 3252,166Ta2O5

Rate (nm/s)Streß (MPa)k < 1 E- 3n (550nm)Material

Properties of optimized HfO2, ZrO2, and Ta2O5 films


UV- Filter Coatings by PARMS

Al2O3 and SiO2 for UV applications

� Dispersion n & k of optimized Al2O3 and SiO2

1,50

1,55

1,60

1,65

1,70

1,75

1,80

1,85

1,90

200 210 220 230 240 250 260 270 280

Wavelength [nm]

Refr

acti

ve I

nd

ex

n

0,0E+00

5,0E-04

1,0E-03

1,5E-03

2,0E-03

2,5E-03

3,0E-03

3,5E-03

4,0E-03

Exti

ncti

on

k

n SiO2 n Al2O3 k SiO2 k Al2O3


UV Filter Coatings by PARMS

Direct optical monitoring @212nm

- BP Filter 212nm, 6 cavity, 90 layer Al2O3 and SiO2

0

10

20

30

40

50

60

70

80

90

100

200 205 210 215 220 225

Wavelength (nm)

Tra

ns

mit

tan

ce

(%

)

measured in chamber

CWL=212.025

FWHM=7.55nm


UV- Filter Coatings by PARMS

Al2O3 for UV applications

� Mirror for 193nm, Result

Mirror for 193nm based on Al2O3 and SiO2 with HELIOS PARMS

0

2

4

6

8

10

12

14

16

18

20

185 190 195 200 205

Wavelength [nm]

Tra

nsm

itta

nce

[%

]

80

82

84

86

88

90

92

94

96

98

100

Refl

ec

tan

ce [

%]

T Helios R Helios R APS


■ Refractive index n at 550nm vs. power ratio Nb/Si+Nb

Co-sputtering: Intermediate refractive indices

Refractive index vs. power ratio of reactive co-sputtered NbxSiyOz layers

1,4

1,5

1,6

1,7

1,8

1,9

2

2,1

2,2

2,3

2,4

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

Power ratio [Nb/Si+Nb]

Re

frac

tiv

e i

nd

ex

n

n at 550nm

SiO2 Nb2O5


Rugate type Filter with co-sputtering

■ Rugate/notch filter design: λλλλ/4 design

Refractive index profile

1,4

1,5

1,6

1,7

1,8

1,9

2,0

2,1

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41

Number of QWOT

Re

fra

cti

ve

in

de

x a

t 6

00

nm


■ Rugate filter with λλλλ/4 layer design

- Comparison with theory and reproducibility

Rugate type Filter with co-sputtering

HELIOS rugate/notch Filter, comparison of theory with 4 repro runs

0

10

20

30

40

50

60

70

80

90

100

350 400 450 500 550 600 650 700 750 800 850

Wavelength [nm]

Tra

ns

mit

tan

ce [

%] 050607-02 Pos. 2

050607-05 Pos. 2

050608-02 Pos. 2

050608-05 Pos. 2

Rugate Disign-41L

Process time 3h


Defect formation Helios prototype, SiO2

� Defect density of < 5 cm-2 for a longer period achievable

� No onset of defect generation until the end of the target lifetime

� Advanced configuration: Circular SiO2 target, RF-powered


LIDT S-on-1 @ 1064nm SiO2 (RF)

� Single layer 4 L

� Substrate Suprasil


LIDT S-on-1 @ 1064nm SiO2 (RF); Ta2O5(MF)

� HR Mirror (HL)^11 L

� Substrate Suprasil




� Substrate Silicon Wafer




� Substrate Silicon Wafer


PARMS Coatings @ 1064nm SiO2/Ta2O5

99.991%

90ppm

0.47nm

Reflection

Total loss

(CRD)

Surface roughness

RMS

158 J/cm2

0%- LIDT

@ 1064nm

H 1 on 1

SiO2/Ta2O5

Si-Wafer

/super polished

Coating material

Substrate

HR Mirror

HL^18L

@1064nm

Design


Conclusion

� PARMS has shown within the last 10 years to be

capable to produce the most complex interference filter

with high productivity

� PARMS can produce coatings with high laser damage

threshold and very low total losses

� Using RF sputtering for SiO2 can lower the defect

density significant


Thank you for your attention !

Magnetron Sputtering of metal oxides - VACUUM … Optics.pdf · Plasma Assisted Reactive Magnetron Sputtering of High Performance Interference Filters A. Zöller, H. Hagedorn, W.

Documents