SPIE conference, 3-8 march 2002, p 1 imec Characterization of a projection lens using the extended Nijboer-Zernike approach 1) Philips Research 2) Delft University of Technology 3) IMEC 4) International Sematech 1 1 2 1 Peter Dirksen, Joseph Braat, Peter De Bisschop, Augustus Janssen, Casper Juffermans, Alvina Williams 3 4
20
Embed
Characterization of a projection lens using the extended ... · PDF fileCharacterization of a projection lens using the extended Nijboer-Zernike approach 1) ... Casper Juffermans,
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
SPIE conference, 3-8 march 2002, p 1 imec
Characterization of a projection lens usingthe extended Nijboer-Zernike approach
1) Philips Research
2) Delft University of Technology
3) IMEC
4) International Sematech
1
1
2
1Peter Dirksen, Joseph Braat, Peter De Bisschop,
Augustus Janssen, Casper Juffermans,Alvina Williams
3
4
SPIE conference, 3-8 march 2002, p 2 imec
Introduction to lens characterization
♦ Lens aberrations have an important contribution to CD variation and image misplacement
♦ Load a reticle, observe aerial image on a CCD camera
Applications to a microscope
Ideal to observe the point spreadfunction of the objective lens
SPIE conference, 3-8 march 2002, p 16 imec
Through-focus aerial image of an isolated hole(λ=193 nm MSM-100)
The dominant term is high order coma
Retrieved Zernike coefficientsExperimental
Best focus- focus + focus
SPIE conference, 3-8 march 2002, p 17 imec
Applications to a scanner
FEM: combine contours into a through-focus aerial image
Single contour of the point spread function
SPIE conference, 3-8 march 2002, p 18 imec
The dominant terms are low order astigmatism and low orderthree-foil.
Retrieved Zernike coefficients
Through-focus aerial image of an isolated hole(ASML PAS 5500/950, λ=193 nm scanner)
Experimental
Best focus- focus + focus
SPIE conference, 3-8 march 2002, p 19 imec
Summary♦ The proof of principle of a new experimental method to
characterize a lens has been given.
♦ The method is based on the observation of the point spreadfunction.
♦ ‘Getting the Zernikes’ is solved analytically: the extended Nijboer-Zernike approach
Applications:
♦ Projection lenses 193, 157 and 13 nm
♦ Optical microscopes, such as reticle inspection tools
SPIE conference, 3-8 march 2002, p 20 imec
Acknowledgement
The authors wish to thank David van Steenwinckel, MichaelBenndorf and Johannes van der Wingerden from PhilipsReseach Leuven for their valuable input and experimentalsupport.