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Proceedings Paper

Wafer flatness for CD control in photolithography
Author(s): Tadahito Fujisawa; Masafumi Asano; T. Sutani; Soichi Inoue; Hiroaki Yamada; Junji Sugamoto; Katsuya Okumura; Tsuneyuki Hagiwara; Satoshi Oka
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Paper Abstract

Wafer-induced focus error is investigated for analysis of our focus budget in photolithography. Using a newly developed wafer monitor, NIWF-300 (Nikon Corp.), we directly measure surface flatness of the wafer placed on wafer holder with vacuum chuck. Single site polished Si wafers were evaluated with NIWF-300 and a conventional flatness monitor. We also investigated the effect of wafer holder using a ring-shape wafer support and a pin-shape wafer support. As a result, we found wafer shape measured in a freestanding condition does not represent surface flatness of the wafer on a holder. The holder has an impact on the wafer surface. The increase of adsorption ratio between wafer and holder improves the surface flatness.

Paper Details

Date Published: 30 July 2002
PDF: 8 pages
Proc. SPIE 4691, Optical Microlithography XV, (30 July 2002); doi: 10.1117/12.474630
Show Author Affiliations
Tadahito Fujisawa, Toshiba Corp. (Japan)
Masafumi Asano, Toshiba Corp. (Japan)
T. Sutani, Toshiba Corp. (Japan)
Soichi Inoue, Toshiba Corp. (Japan)
Hiroaki Yamada, Toshiba Corp. (Japan)
Junji Sugamoto, Toshiba Corp. (Japan)
Katsuya Okumura, Univ. of Tokyo (Japan)
Tsuneyuki Hagiwara, Nikon Corp. (Japan)
Satoshi Oka, Shin-Etsu Handotai Co., Ltd. (Japan)

Published in SPIE Proceedings Vol. 4691:
Optical Microlithography XV
Anthony Yen, Editor(s)

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