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Proceedings Paper

Tritone PSM and its performance
Author(s): Makoto Kohzuma; Kazuaki Chiba; Hiromasa Unno; Yasutaka Kikuchi; Yoshiro Yamada; Masao Otaki
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Paper Abstract

The halftone phase shift mask (PSM) gives a significant improvement on DOF for hole pattern printing on wafer. However, we need to be careful when we use it on other patterns such as line and space or patterns surrounded by bright field, because sub-peak effect could cause deterioration of those patterns when they are printed on wafer. Toppan presents a new structure in which Cr film is partially placed on the half tone surface. With this structure, so called Tri-tone PSM, we can block harmful light transmission for non-hole patterns, while keeping the full characteristics of PSM effect on targeted patterns. This structure could also prevent the line shortening problem. Using this structure we can get good printability on smaller geometry without using optical proximity correction (OPC) patterns (serif, etc.). Of course this method can offer a perfect shielding of the opaque ring which prevent the wafer damage caused by light leakage. By using this Tri-tone structure, the application of half tone PSM, which is so far limited to hole patterns, would be extended to line patterns.

Paper Details

Date Published: 12 February 1997
PDF: 14 pages
Proc. SPIE 3236, 17th Annual BACUS Symposium on Photomask Technology and Management, (12 February 1997); doi: 10.1117/12.301197
Show Author Affiliations
Makoto Kohzuma, Toppan Printing Co., Ltd. (Japan)
Kazuaki Chiba, Toppan Printing Co., Ltd. (Japan)
Hiromasa Unno, Toppan Printing Co., Ltd. (Japan)
Yasutaka Kikuchi, Toppan Printing Co., Ltd. (Japan)
Yoshiro Yamada, Toppan Printing Co., Ltd. (Japan)
Masao Otaki, Toppan Printing Co., Ltd. (Japan)

Published in SPIE Proceedings Vol. 3236:
17th Annual BACUS Symposium on Photomask Technology and Management
James A. Reynolds; Brian J. Grenon, Editor(s)

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