Extended Nijboer-Zernike (ENZ) based imaging into an image region containing a layered configuration
1S. van Haver, 1J.J.M. Braat, 2A.J.E.M. Janssen, 1S.F. Pereira 1TUDelft, TNW-IST Optics Research Group, Lorentzweg 1, 2628CJ Delft, the Netherlands
2Philips Research Europe, HTC 36, 5656AE Eindhoven, the NetherlandsContact: [email protected]
EOS AIT Jena, June 10th 2009, 18:00-18:20.
www.nijboerzernike.nl
Simplified transmittive
mask object
Computed near-field
when illuminated by an x-polarized plane wave
Extended Nijboer-Zernike imaging
•
2 years ago at EOS AIT in Lille we have given a proof of concept on ENZ-based imaging
www.nijboerzernike.nl
Extended Nijboer-Zernike imaging
•
2 years ago at EOS AIT in Lille we have given a proof of concept on ENZ-based imaging
Electric field in the
exit pupil
Through-focus image of the mask computed with
ENZ-imaging algorithm (NA =0.95)
www.nijboerzernike.nl
Entrance
pupil
Extended Nijboer-Zernike imaging
•
ENZ-imaging model vs common Fourier based imaging
complex transmission
function
complex transmission
function
+
low-pass filter
FT FT-1
ENZ
Fourier
ENZ computes the image directly from
the Zernike expansion of the
complex exit pupil distribution
Image is obtained by inverse Fourier transforming the filtered spectrum
ENZ
www.nijboerzernike.nl
Extended Nijboer-Zernike imaging
•
ENZ-imaging model vs. common Fourier based imaging
ENZ-imaging:• Novel method
• Isolated objects
• Potentially fast using tabulation
• Highly accurate#
•
Current work to include image formation in stratified media
Fourier-imaging:• Established widespread method
• periodic objects
• Fast using FFT
•
Some concern about accuracy (applied approx.)
#
S. van Haver et al., J. Opt. Soc. Am. A 26, 1221-1234 (2009).
www.nijboerzernike.nl
Multilayer ENZ-imaging
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Schematic representation of the configuration under consideration:
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Multilayer ENZ-imaging
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Effective pupil: Homogeneous imaging
pupildistribution
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Multilayer ENZ-imaging
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Effective pupils: half-space imaging
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Multilayer ENZ-imaging
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Effective pupils: 3-layer image space
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Multilayer ENZ-imaging
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Insert effective backward and forward propagating distributions into Debye Diffraction integral
•
Apply ENZ semi-analytic solution!
Forward propagating
Backward propagating
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Multilayer ENZ-imaging example 1:
•
Three models to represent a lithographic stack
(water immersion lithography; λ=193nm, NA=1.368)
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Multilayer ENZ-imaging example 1:
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Single water-photoresist interface
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Multilayer ENZ-imaging example 1:
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Simple stack including highly reflective substrate
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Multilayer ENZ-imaging example 1:
•
Advanced lithographic stack with ARC
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Multilayer ENZ-imaging example 2:•
High-capacity optical data storage with Solid Immersion Lens:
air-gap
SIL
SIL
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Conclusions & Discussion
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ENZ Image formation in stratified media is possible by using layer dependent pupil distributions
•
Accurate semi-analytic image formation•
Tabulated basic functions:•
Layer configuration changes do not require a new full simulation
•
Efficient optimization of multilayer stacks•
Zernike expansion of the pupil contains valuable information on layer induced aberrations, without calculating the actual image
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Questions?
Visit:http://www.nijboerzernike.nl
Acknowledgements:
