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A SHARP LOOK AT FUTURE NODES
OF EUV LITHOGRAPHY
SHARP High-NA actinic Reticle Review Project
Markus Benk, Weilun Chao, Ryan Miyakawa,Kenneth Goldberg, Patrick Naulleau
2018 International Workshop on EUV LithographyLawrence Berkeley National Lab, Berkeley, June 13
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1Overview 2018 EUVL Workshop, Berkeley
TitleSource: Synchrotron
Optics: Zoneplate lenses
4×NA: 0.25–0.625
Sigma: Programmable
Navigation: 2-µm position accuracy
Throughput: up to 24 sites/hour
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2Introduction
ApertureSource
angular
spectrum
2018 EUVL Workshop, Berkeley
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2Introduction
Fourier
synthesis
illuminator
Zoneplate
lens
2018 EUVL Workshop, Berkeley
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3Fourier Synthesis Illuminator
▪ 0.625 4xNA
10° CRA
=0.8
=1 outline
Illuminator angular range
2018 EUVL Workshop, Berkeley
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4
Pupil fill▪ Conventional
▪ 0.33 4xNA, 6° CRA
Pupil diagram YAG image, 4mm below focus
Liu, SPIE 90480Q (2014)
Fourier Synthesis Illuminator 2018 EUVL Workshop, Berkeley
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Pupil fill▪ Crosspole
▪ 0.33 4xNA, 6° CRA
Pupil diagram YAG image, 4mm below focus
Liu, SPIE 90480Q (2014)
Fourier Synthesis Illuminator 2018 EUVL Workshop, Berkeley
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Pupil fill▪ Crosspole
▪ 0.33 4xNA, 6° CRA
Pupil diagram Modulation of flux in pupil channels
Liu, SPIE 90480Q (2014)
Fourier Synthesis Illuminator 2018 EUVL Workshop, Berkeley
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Pupil fill▪ Quasar
▪ 0.33 4xNA, 6° CRA
Pupil diagram Modulation of flux in pupil channels
Liu, SPIE 90480Q (2014)
Fourier Synthesis Illuminator 2018 EUVL Workshop, Berkeley
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Pupil fill▪ Freeform Source
▪ 0.33 4xNA, 6° CRA
Pupil diagram
Fourier Synthesis Illuminator 2018 EUVL Workshop, Berkeley
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4Introduction 2017 EUVL Workshop, Berkeley
5 mm
▪ Gold pattern onSi3N4-membranes
▪ Magnetic mounting
▪ Kinematic positioning 2 mm
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Chip B
▪ Zernike Phase Contrast
▪ Differential Interference Contrast
▪ Stereoscopic imaging
▪ Cubic Phase Modulation
Zoneplates
6
Standard Zoneplates:
▪ 0.25 to 0.625 4xNA
▪ 6° to 10° CRA
▪ 5 azimuthal angles 160 µm
Zoneplates
0.625 4xNA:
▪ 22-nm hp resolution on the mask
▪ 5.5 nm hp resolution wafer scale
(for a 4x system)
2018 EUVL Workshop, Berkeley
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Zoneplates
6
Standard Zoneplates:
▪ 0.25 to 0.625 4xNA
▪ 6° to 10° CRA
▪ 5 azimuthal angles
Chip B
▪ Zernike Phase Contrast
▪ Differential Interference Contrast
▪ Stereoscopic imaging
▪ Cubic Phase Modulation
160 µm
Chip C
▪ Elliptical zoneplates
Zoneplates 2018 EUVL Workshop, Berkeley
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Thin-absorber wafer mask
7Absorber study
Mo/Si Multilayer
Ruthenium
Chrome
40-nm Nickel absorber
Silicon wafer
J. Micro/Nanolith. MEMS MOEMS 15(3),033501 (2016)
2018 EUVL Workshop, Berkeley
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Thin-absorber wafer mask
7
4x/4x 4x/8x
2 µm 2 µm
2018 EUVL Workshop, BerkeleyAbsorber study
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Comparison of absorbers
8
Future Study
▪ Two photomasks with identical patterns
▪ Mask SEM characterization
2018 EUVL Workshop, BerkeleyAbsorber study
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Comparison of absorbers
8
Initial Study
▪ Identify comparable patterns on available photomasks
2018 EUVL Workshop, BerkeleyAbsorber study
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▪ 0.33 4x NA
▪ Quasar illumination ▪ 22.5 nm CD (1x)
200 nm (1x)
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Patterns
▪ Ta-based ▪ Nickel
200 nm (1x)
2018 EUVL Workshop, BerkeleyImaging
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Patterns
▪ Ta-based V ▪ Nickel▪ Ta-based H
100 nm (1x) 100 nm (1x)100 nm (1x)
▪ 0.55 4x/8x NA
▪ Quasar illumination ▪ 12.5 nm CD (1x)
2018 EUVL Workshop, BerkeleyImaging
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Contrast and NILS
▪ Ta-based ▪ Nickel
200 nm (1x) 200 nm (1x)
▪ 0.33 4x NA
▪ Quasar illumination
22.5 nm
CD (1x)
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Contrast and NILS
▪ Ta-based ▪ Nickel
▪ 0.33 4x NA
▪ Quasar illumination
2018 EUVL Workshop, BerkeleyImaging
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Contrast and NILS
200 nm (1x)
▪ 0.33 4x NA
▪ Nickel
2018 EUVL Workshop, BerkeleyImaging
0.33 4xNA:
▪ higher on vertical
features
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Contrast and NILS
200 nm (1x)
▪ 0.33 4x NA
▪ higher contrast in V
▪ 0.55 4x/8x NA
▪ higher contrast in H
100 nm (1x)
2018 EUVL Workshop, BerkeleyImaging
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Contrast and NILS
▪ 0.33 4x NA
▪ higher contrast in V
▪ 0.55 4x/8x NA
▪ higher contrast in H
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▪ 0.33 4xNA, regular mask
▪ balanced Quasar
▪ 0.33 4xNA, regular mask
▪ imbalanced Quasar
6º
0º
12º
100%
70%
Optimized source
2018 EUVL Workshop, BerkeleyImaging
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▪ 0.33 4xNA, Ta-based
▪ balanced Quasar
▪ 0.33 4xNA, Ta-based
▪ imbalanced Quasar
Optimized source 200 nm (1x)
▪ 22.5 nm CD (1x)
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12
Imbalanced Quasar:
▪ higher NILS for both
grating orientations
▪ wider focus range
Optimized source
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a ▪ Image ia
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a ▪ Image ia
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a ▪ Image ia
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a ▪ Image ia
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a ▪ Image ia
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil Channel a ▪ Image ia
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Image I = ia
a
å▪ Pupil
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil ▪ Image I = ia
a
å
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132018 EUVL Workshop, BerkeleyImaging
Source Optimization
▪ Pupil ▪ Image I = ia
a
å
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142018 EUVL Workshop, BerkeleyImaging
Source Optimization▪ Quasar
▪ 40-nm (1x) dense contacts
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142018 EUVL Workshop, BerkeleyImaging
Source Optimization▪ Quasar
▪ 40-nm (1x) dense contacts
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142018 EUVL Workshop, BerkeleyImaging
Source Optimization▪ Quasar ▪ Freeform Source
▪ 40-nm (1x) dense contacts
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142018 EUVL Workshop, BerkeleyImaging
Source Optimization▪ Quasar ▪ Freeform Source
▪ 40-nm (1x) dense contacts
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SummarySHARP High-NA Actinic Reticle
Review Project
▪ Emulation of imaging in
EUV scanner
▪ Emulation of anamorphic imaging
▪ Increased imaging performance
with thinner absorber both
for 0.33 and 0.55 anamorphic
▪ Source Optimization
demonstration
2018 EUVL Workshop, Berkeley
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Thanks to
our users.
Thanks to
INTEL for funding
SHARP operations.
EUV infrastructure at
Berkeley is funded through
the EUREKA program.
2018 EUVL Workshop, Berkeley
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Thanks to
our users.
Thanks to
INTEL for funding
SHARP operations.
Thank you!
2018 EUVL Workshop, Berkeley
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AIS: Characterization of aberrations
8Zoneplates
▪ Through-focus image data
of 4 grating orientations and
12 monopole illuminations
▪ Aberrations solved from
measured focus shifts
using least-squares approach
90º (3 points)
0º (3 points)
135º (3 points)
45º (3 points)
2018 EUVL Workshop, Berkeley
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Field dependent aberrations
9Zoneplates
Sweet spot (Z4 to Z8) : 7.2 ml RMS (l EUV /139)
▪ Ideal 0.33 4xNA zoneplate ▪ AIS measurement
Fie
ld location (
um
)
Fie
ld location (
um
)
2018 EUVL Workshop, Berkeley
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Field dependent aberrations
9Zoneplates
Sweet spot (Z4 to Z8) : 4.4 ml RMS
▪ Ideal 0.33 4xNA zoneplate
Latest measurement
Fie
ld location (
um
)
2018 EUVL Workshop, Berkeley
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Programmed aberrations
9Zoneplates
Astigmatism zoneplate
2018 EUVL Workshop, Berkeley
Mixed Zernike zoneplate
programmed
measuredComa zoneplate
Sperical aberration zoneplate
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Programmed aberrations
9Zoneplates
Astigmatism zoneplate
2018 EUVL Workshop, Berkeley
Mixed Zernike zoneplate
programmed
measuredComa zoneplate
Sperical aberration zoneplate
RMS error:
3.2 mλ (0.043 nm)
RMS error:
4.1 mλ (0.055 nm)
RMS error:
5.2 mλ (0.070 nm)RMS error:
4.8 mλ (0.065 nm)