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Performance Characterization of the
EUV optical imaging module of the
Reticle Imaging Microscope (RIM)
R. Hudyma
Hyperion Development LLC
H. Glatzel, J. Daniel, K. Khajehnouri, U. Mueller, T.
Roff, J. Rosenbohm, S. Sporer
Tinsley Labs

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C
2
C
1
C
3
C
4
M
1
M
2
Y
X
Z
The EUV optical system
Koehler Ilumination:
Source imaged to
intermediate pupil plane
w/ coherence apertures
source
Off-axis
Schwarzschild
condensor
Equal-radii
Cassegrain
10x Microscope
• Diffraction-limited imaging and
inspection of Reticles at 13.5 nm (EUV)
• Description of entire RIM system by
M. Booth et al, SPIE vol 5751 (2005), p. 78
[Ref 1]
• Areas of Responsibilities:
• Exitech: entire tool
• Hyperion Development:
optical design, lithographic
modeling
• Osmic: High-Reflectivity coatings
• Tinsley: EUV optical system –
imaging and illumination modules,
system integration & alignment
Reticle
Scintillator
Relay
optics
700mm

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The imager module
M1
mirror
M2
mirror
3 bipods w/
flexures
6 Struts w/
flexures &
picomotors
3 bipods w/
flexures
All metal
parts in
Invar
Optics in
Zerodur
• Equal-radii Cassegrain
• 10x mag
• NA = 0.0625
(off-axis subaperture)

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Scope of this Poster
optical surface topology of imager mirrors
- typical surface data
- 3D maps using various instruments
- average Power Spectral Density (PSD)
- PSD fit
- MSFR and HSFR RMS
transmitted wavefront error of imager module
- full annulus
- subaperture
- Zernike expansion
optical performance predictions
- comparison as-designed versus as-build
- 128 nm L/S and 72 nm isolated lines
- aerial images
- ED and DOF analysis

5. Surface Metrology
•
Phase Shifting
Interferometer (PSI)
Phase Measuring
Microscope (PMM)
4x Mag
Phase Measuring
Microscope (PMM)
50x Mag
Atomic Force
Microscope (AFM)
95 mm
0.3 mm
3.3 mm
2 um
FoV
+ 3 nm
- 3 nm

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1.00E-08
1.00E-07
1.00E-06
1.00E-05
1.00E-04
1.00E-03
1.00E-02
1.00E-01
1.00E+00
1.00E+01
1.00E+02
0.01 0.1 1 10 100 1000 10000 100000 1000000
spatial frequency (1/mm)
PSD(nm^2*mm)
+ 3 nm
- 3 nm
Fourier Transformation of surface maps
1D Power Spectral Density (PSD)
PSD(f) = A*f S
lg(PSD) = lg(A) + s*lg(f)

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1.00E-08
1.00E-07
1.00E-06
1.00E-05
1.00E-04
1.00E-03
1.00E-02
1.00E-01
1.00E+00
1.00E+01
1.00E+02
0.01 0.1 1 10 100 1000 10000 100000 1000000
spatial frequency (1/mm)
PSD(nm^2*mm)
MiniFiz
4X
50X
f^(-1.06)*10^(-1.67)
AFM
Typical PSD of surface errors

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Achieved integrated Surface Errors
for various imager mirrors
Error type spatial period WFE RMS
range (nm)
Surface Figure Error (LSFR) CA … 1 mm 0.25 .. 0.39
Mid-Spatial Frequency Error (MSFR) 1 mm … 1 µm 0.28 .. 0.36
High-Spatial Frequency Error (HSFR) 1 µm … 1 nm 0.33 .. 0.37

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TWF RMS = 0. 79 nm nm
nm
Transmitted Wavefront Error
of imager module

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Simulation of as-designed and as-built performance
shows excellent agreement for 128 nm L/S
• Modeling assumptions
– 128 nm dense L/S
– NA = 0.0625
– Sigma = 0.60
– Flare = 0%
– “ As-designed” =
Zernikes computed from
optical design code
– “ As-built” = Measured
Zernikes
– Thin mask
• Results
– Contrast, NILS, and CD
are in excellent
agreement
– Image shift that can be
removed via system
alignment
RIM Aerial Image Comparison "As-Designed "
vs. "As-Built" for 128 nm L/S (s = 0.60, no flare)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-128 -96 -64 -32 0 32 64 96 128
Simulatin domain (nm)
As-Designed
As-Built
Intensity(au)

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ED analysis shows no meaningful degradation in
measurement capability due to aberrations for 128 nm L/S
RIM As-designed RIM As-built

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• Modeling assumptions
– 72 nm isolated
– NA = 0.0625
– Sigma = 0.60
– Flare = 0%
– “ As-designed” =
Zernikes computed from
optical design code
– “ As-built” = Measured
Zernikes
– Thin mask
• Results
– Contrast, NILS, and CD
are in excellent
agreement
– Image shift that can be
removed via system
alignment
RIM Aerial Image Comparison "As-Designed " vs.
"As-Built" for 72 nm isolated lines (s = 0.60, no flare)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
-128 -96 -64 -32 0 32 64 96 128
Simulatin domain (nm)
As-Designed
As-Built
Intensity(au)
Simulation of as-designed and as-built performance
shows excellent agreement for isolated 72 nm lines

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ED analysis shows no meaningful degradation in
measurement capability due to aberrations for 72 nm
isolated lines
RIM As-designed RIM As-built

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Summary: optical performance prediction
• Simulations using as-designed Zernikes and as-
built Zernikes demonstrate that the imagery shows
excellent correlation under the stated simulation
assumptions
– Predicted as-built image contrast, NILS, CD, and ED
characteristics show excellent correlation to baseline
design
• Low-order aberrations induced by mirror fabrication
and alignment errors will have little or no impact on
RIM tool performance
– Zernike based tolerance method and error budgeting
procedure developed specifically for the RIM tool has been
validated

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Acknowledgements & References
Acknowledgements
• Special thanks to the teams at
- Exitech,
- Hyperion,
- LLNL,
- Osmic,
- SSG and
- Tinsley
for supporting this work with passion and dedication
• Ian Wallhead at Exitech for supporting our development activities and providing
specifications and valuable feedback
• Layton Hale at LLNL for contributions to the mechanical design and structural analysis
References
1. M. Booth et al, “High-resolution EUV imaging tools for resist exposure and aerial
image monitoring” , SPIE vol 5751 (2005), p. 78.

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End of presentation