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Proceedings Paper

Overlay and lens distortion in a modified illumination stepper
Author(s): Chul-Seung Lee; Jeong Soo Kim; Ikboum Hur; Young-Mog Ham; Soo-Han Choi; YeonSeon Seo; Scott M. Ashkenaz
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Paper Abstract

Optical lithography, when extended by phase shift mask technology and modified illumination techniques, is a promising technology for sub-half-micron devices. Modified illumination can improve the resolution limit and depth of focus, but the imaging profile is changed, with pattern type, direction, and density having an effect on the result. The uniformity of the illumination system also differs according to aperture type. Because lens distortion may be affected by the aerial image and structure of illumination optics, we can expect that a modified illumination system may affect lens distortion and overlay accuracy in a real process. A comparison of changes in overlay and lens distortion was done for different illumination conditions. Focus was varied for each combination. As a result, we can observe the variation of overlay error in a modified illumination system relative to the conventional system. To use modified illumination in sub-half-micron processes distortion error must be reduced.

Paper Details

Date Published: 17 May 1994
PDF: 7 pages
Proc. SPIE 2197, Optical/Laser Microlithography VII, (17 May 1994); doi: 10.1117/12.175404
Show Author Affiliations
Chul-Seung Lee, Hyundai Electronics Industries Co., Ltd. (South Korea)
Jeong Soo Kim, Hyundai Electronics Industries Co., Ltd. (South Korea)
Ikboum Hur, Hyundai Electronics Industries Co., Ltd. (South Korea)
Young-Mog Ham, Hyundai Electronics Industries Co., Ltd. (South Korea)
Soo-Han Choi, Hyundai Electronics Industries Co., Ltd. (South Korea)
YeonSeon Seo, KLA Instruments Korea (South Korea)
Scott M. Ashkenaz, KLA Instruments Corp. (United States)

Published in SPIE Proceedings Vol. 2197:
Optical/Laser Microlithography VII
Timothy A. Brunner, Editor(s)

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