Extended Nijboer-Zernike (ENZ) based imaging into an image ... · 2 years ago at EOS AIT in Lille...

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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: s.vanhaver@tudelft.nl

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

Electric field in the

exit pupil

Through-focus image of the mask computed with

ENZ-imaging algorithm (NA =0.95)

Entrance

ENZ-imaging model vs common Fourier based imaging

complex transmission

function

complex transmission

function

low-pass filter

FT FT-1

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-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).

Multilayer ENZ-imaging

Schematic representation of the configuration under consideration:

Effective pupil: Homogeneous imaging

pupildistribution

Effective pupils: half-space imaging

Effective pupils: 3-layer image space

Insert effective backward and forward propagating distributions into Debye Diffraction integral

Apply ENZ semi-analytic solution!

Forward propagating

Backward propagating

Multilayer ENZ-imaging example 1:

Three models to represent a lithographic stack

(water immersion lithography; λ=193nm, NA=1.368)

Single water-photoresist interface

Simple stack including highly reflective substrate

Advanced lithographic stack with ARC

Multilayer ENZ-imaging example 2:•

High-capacity optical data storage with Solid Immersion Lens:

air-gap

Conclusions & Discussion

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

Questions?

Visit:http://www.nijboerzernike.nl

Acknowledgements:

Extended Nijboer-Zernike (ENZ) based imaging into an image ... · 2 years ago at EOS AIT in Lille...

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