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Proceedings Paper

Practical approach to full-field wavefront aberration measurement using phase wheel targets
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Paper Abstract

An automated aberration extraction method is presented which allows extraction of lithographic projection lens' aberration signature having only access to object (mask) and image (wafer) planes. Using phase-wheel targets on a two-level 0/π phase shift mask, images with high sensitivity to aberrations are produced. Zernike aberration coefficients up to 9th order have been extracted by inspection of photoresist images captured via top-down SEM. The automated measurement procedure solves a multi-dimensional optimization problem using numerical methods and demonstrates improved accuracy and minimal cross-correlation. Starting with a detailed procedure analysis, recent experimental results for 193-nm projection optics in commercial full field exposure tools are discussed with an emphasis on the performance of the aberration measurement approach.

Paper Details

Date Published: 15 March 2006
PDF: 9 pages
Proc. SPIE 6154, Optical Microlithography XIX, 61540Y (15 March 2006); doi: 10.1117/12.657928
Show Author Affiliations
Lena V. Zavyalova, Rochester Institute of Technology (United States)
Bruce W. Smith, Rochester Institute of Technology (United States)
Anatoly Bourov, Rochester Institute of Technology (United States)
Gary Zhang, Texas Instruments Inc. (United States)
Venugopal Vellanki, Benchmark Technologies (United States)
Patrick Reynolds, Benchmark Technologies (United States)
Donis G. Flagello, ASML US, Inc. (United States)

Published in SPIE Proceedings Vol. 6154:
Optical Microlithography XIX
Donis G. Flagello, Editor(s)

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