Multilayer mirrors for EUVL, status progress · Multilayer mirrors for EUVL, status progress Yuriy Platonov, Jim Rodriguez, Michael Kriese, Vladimir Martynov Rigaku Innovative Technologies,

Multilayer mirrors for EUVL, status progress

Yuriy Platonov, Jim Rodriguez, Michael Kriese, Vladimir Martynov

Rigaku Innovative Technologies, 1900 Taylor Rd., Auburn Hills, MI 48326, USA

Outline

• Collector optics

• Illuminator optics

• Thermal stability

• Substrates ion beam polishing

• Barrier layers for La/B4C

• Conclusion

2012 EUVL Workshop. Maui, June 4-8, 2012

Collector optics deposition

• Vacuum (load-locked)

– 10-8 ultimate

– 10-9 water

– 15min from atm to 10-6

• Process

– 5 planar magnetron (RF,DC)

– 4 process gases

– 0.5 to 5 mTorr

– linear ion source

– 20-100 particles/cm2 on optical surface

• Dual Spinning Capability

#1: 550mm dia x 220mm thick

#2: 175mm dia x 35mm thick

(Compatible with velocity motion

control)

• Mechanical

– 500 x 1500mm carrier (2)

– 0.2mm accuracy

– 1-133 mm/sec (±0.1%)

– velocity profiling (6 pts/mm)


Radial variation of Reflectivity

Performance has been improved

Collector optics


3

Angular variation at a fixed radius

is within tolerance of the measurement

±0.25% full PV range ±0.35% full PV range

Collector optics


4

Illuminator optics


EUV measurements were done at CXRO and NIST

EUV measurement results

5

M1 M2

R = 69.2%

l = 13.36nm

Regular Wafer

(AFM RMS=1.5A at 10mm)

Ion Mill treatment

(AFM RMS=1A at 10mm)

Mo/Si multilayer

Ion beam polishing


Improvement by substrates polishing

69.2% vs 68.7%

6

Substrate smoothing: Sample 1

Spatial periods RMS Roughness

>1 mm 11Å 7Å

<1 mm 10Å 1.2Å


7

Substrate smoothing: Sample 2

Spatial periods RMS Roughness

>1 mm 4Å 4Å

<1 mm 2Å 1Å

Ion beam polishing


8

“Dark field”

imaging:

Sample 1

Ion beam polishing


Before Ion Mill After Ion Mill_2

After Ion Mill_3 After Ion Mill_5

9

PV smoothing: after Ion Mill_5

Ion beam smoothing


10

Ion beam polishing

High Spatial Frequencies Roughness

Change in HSFR depends on polishing process


11

2259.116

1506.077

1129.558

903.6463

753.0386

645.4617

564.779

502.0257

451.8232

410.7483

376.5193

347.5563

322.7308

301.2154

282.3895

265.7783

251.0129

237.8017

225.9116

215.1539

205.3742

196.4449

188.2597

180.7293

173.7781

0.01

0.1

1

10

100

1000

10000

100000

0.1110100100010000

PSD (nm^3)

Spatial Periods (microns)

Before Ion Milling 1.25xBefore Ion Milling 10xBefore Ion Milling 40xAfter Ion Milling 1.25xAfter Ion Milling 10xAfter Ion Milling 40x

Ion beam smoothing

Mid Spatial Frequency Roughness

No change in MSFR


12

Thermal stability

Mo/Si taken from: C. Montcalm, Eng. Opt. 40, 469 (2001) others from: S. Yulin, SPIE 5751, 1155 (2005)

Materials choice Barrier layer

2012 EUVL Workshop. Maui, June 4-8, 2012 13

C barrier layer B4C barrier layer

Barrier Layer: d-spacing change (Cu-Kα)

Thermal stability


C barrier 250oC: <0.2% loss 300oC: <0.2% loss

B4C barrier 250oC: ~0.3% loss 300oC: ~0.8% loss

14

Barrier Layer: λ(peak) change


Thermal stability

C barrier 250oC: ~0.1% 300oC: ~0.4%

B4C barrier 250oC: ~0.5% 300oC: ~0.8%


Thermal stability Barrier Layer: EUV reflectivity change


C barrier 400oC: <0% loss 600oC: ~10% loss

B4C barrier 400oC: <2% loss 500oC: ~100% loss


R = 69.7%

λ = 13.29nm

EUV reflectivity of Mo/Si

multilayer with barrier layers

Barrier layers

Measurements were done at NIST in June 2012

Measurements in 2 weeks

after deposition.

The multilayer was stored in

a typical room environment.


0

0.1

0.2

0.3

0.4

0.5

0.6

6.6 6.65 6.7 6.75 6.8 6.85 6.9

74deg.75deg.76deg.

77deg.78deg.79deg.

80deg.81deg.82deg.

83deg.84deg.85deg.

Wavelength, nm

Previous year results

R(max)=42.8% at ~6.63nm R(max)=49.83% at ~6.656nm

La/B4C structure La2O3/B4C structure

Measurements at CXRO, March 2011

Measurements at New Subaru, May, 2011


ML for 6.X nm

18


A typical La/B4C structure

Cu-Kα (λ=1.54Å) fitting

ML for 6.X nm

19


Barrier layer for La/B4C structure

0.001

0.01

0.1

1

0 1 2 3 4

Experimental reflectivity at Cu-Ka

R(La/B4C)R(B4C/X/La)

Theta, deg.

ML for 6.X nm

20


6.4 6.5 6.6 6.7 6.80

10

20

30

40

50

Pe

ak r

efle

cta

nce

Wavelength (nm)

36442-1

36446-1

ML for 6.X nm

0

0.1

0.2

0.3

0.4

0.5

6.4 6.45 6.5 6.55 6.6 6.65 6.7 6.75 6.8

Experimental reflectivity of B4C/X/La structure.XRO#36442

75deg.76deg.77deg.78deg.79deg.80deg.81deg.82deg.83deg.84deg.85deg.86deg.87deg.

Wavelength, nm

EUV reflectivity results

Measurements done at CXRO in May, 2012

0

0.1

0.2

0.3

0.4

0.5

6.3 6.4 6.5 6.6 6.7 6.8 6.9

Experimental reflectivity of B4C/X/La structure.XRO#36446

70deg.71deg.72deg.73deg.74deg.75deg.76deg.77deg.78deg.79deg.80deg.81deg.82deg.83deg.84deg.85deg.

Wavelength, nm

Rmax=45.15% @ 6.656nm

Rmax=45.87% @ 6.665nm

λ(Rmax) ≈ 6.656nm – 6.665nm

21

Optical constants and maximum reflectivity

20

30

40

50

60

70

80

90

65.5 66 66.5 67

Reflectivity of La/B4C structures versus wavelengthcalculated with two different sets of B4C constants.

R(cxro), %

R(souf li), %

Wavelength, Å

(max)=6.602nm

R(max)=80%

(max)=6.624nm

R(max)-67.2%

CXRO - B4C constants are from CXRO website

Soufli - B4C constants are from R. Soufli et al, Applied Optics, 47, 25 (2008)

6.64nm R(max) for La2O3/B4C

6.656nm R(max) for La/B4C and B4C/X/La


ML for 6.X nm

6.665nm R(max) for La/X/B4C

22


0

0.1

0.2

0.3

0.4

0.5

6.5 6.55 6.6 6.65 6.7 6.75 6.8

Experimental reflectivity of La/X/B4C (XRO#36461)versus B4C/X/La (XRO#36446) structures

R(La/X/B4C)R(B4C/X/La)

Wavelength, nm

ML for 6.X nm

Barrier layer on B4C or on La ?

23

Conclusion • Collector optics

+/- 0.5% reflectivity variation across CA, R~67%

+/- 0.25% λc variation at fixed radii

• Illuminator optics 45 degrees off-axis ellipsoids

< +/- 1% d-uniformity; R ≈ 66%

• Substrates ion beam polishing HSFR: smoothing from 10Å to 1.2Å

MSFR: no change

• Mo/X/Si/X ML thermal stability – Δλ ~ 0.1% @ 250oC; Δλ ~ 0.4% at 300oC

– ΔR ~0% loss at 400oC; ΔR ~ 10% loss at 600oC

– R(max) = 69.7% at ~13.3nm

• La/X/B4C and B4C/X/La performance – Structural improvement based on Cu-Kα testing

– ~46% for B4C/X/La and ~16% for La/X/B4C


0

0.1

0.2

0.3

0.4

0.5

6.5 6.55 6.6 6.65 6.7 6.75 6.8

Experimental reflectivity of La/X/B4C (XRO#36461)versus B4C/X/La (XRO#36446) structures

R(La/X/B4C)R(B4C/X/La)

Wavelength, nm

24

Acknowledgement

• RIT

G. Fournier, J. Hummel, C. Coffel, T. Camitan

• CXRO

E. Gullikson

• New Subaru

H. Kinoshita, T. Harada, T. Watanabe,

• NIST

C. Tarrio, S. Grantham, T.B. Lucatorto


Thank you

Osmic® Products

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Multilayer mirrors for EUVL, status progress · Multilayer mirrors for EUVL, status progress Yuriy Platonov, Jim Rodriguez, Michael Kriese, Vladimir Martynov Rigaku Innovative Technologies,