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Proceedings Paper

Influence of photoresist on the optical performance of high NA steppers
Author(s): Donis G. Flagello; Richard Rogoff
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Paper Abstract

The theoretical foundation for high NA imaging, which has been previously presented is used to examine the effects of the photoresist film on the optical performance of an advanced lithographic lens. We show that the high NA image formed by the lens within the photoresist interacts with the development process; hence, the image behavior is highly correlated to process parameters such as development and photoresist thickness. The effects of aberrations with the photoresist are explored by comparing aberrated and ideal systems. Changes in field related focal deviations and depth of focus (DOF) are shown. A general rule-of-thumb equation is formulated that relates best focus, i.e., focal plane deviation, derived from either simulations or experiments to the amount of wavefront aberrations. The relationship is extended for an approximate calculation of DOF change with aberration. Since the measurement of various amounts of aberration is dependent on the photoresist processing, definitions of best focus using testing procedures such as focus/exposure matrices, are influenced by the ability to measure optical performance.

Paper Details

Date Published: 26 May 1995
PDF: 9 pages
Proc. SPIE 2440, Optical/Laser Microlithography VIII, (26 May 1995); doi: 10.1117/12.209265
Show Author Affiliations
Donis G. Flagello, ASM Lithography BV (Netherlands)
Richard Rogoff, ASM Lithography BV (Netherlands)

Published in SPIE Proceedings Vol. 2440:
Optical/Laser Microlithography VIII
Timothy A. Brunner, Editor(s)

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