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Proceedings Paper

Dependence of compaction in fused silica on laser pulsewidth at 248 nm (Abstract Only)
Author(s): Richard L. Sandstrom; Richard G. Morton; Thomas P. Duffey
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Paper Abstract

Designers of DUV lithographic lenses are faced with serious materials problems relating to compaction and color-center formation in fused silica, especially at 193 nm. However, these problems, while less sever, are not negligible at 248 nm. Compaction appears to be the more serious, since it degrades imaging performance and effectively sets the lifetime limit for the lens. Previous damage studies have clearly shown that fused silica compacts as a function of the parameter grouping (NI2/(tau) ), where (tau) is the pulsewidth. This fact has strongly influenced the design of the excimer laser light source by stressing repetition rate over pulse energy as a way of achieving high average power, and by driving the optical pulsewidth to be as long as possible. These studies, however, have emphasized the dependence of damage rates on the energy density I(mJ/cm2), whereas the optical pulsewidth (tau) has been given only cursory attention and has not been well controlled during the damage experiments. In this paper we report the results of an experiment to more clearly establish the functional dependency of compaction on laser pulsewidth.

Paper Details

Date Published: 7 April 1999
PDF: 3 pages
Proc. SPIE 3578, Laser-Induced Damage in Optical Materials: 1998, (7 April 1999); doi: 10.1117/12.344434
Show Author Affiliations
Richard L. Sandstrom, Cymer Inc. (United States)
Richard G. Morton, Cymer Inc. (United States)
Thomas P. Duffey, Cymer Inc. (United States)

Published in SPIE Proceedings Vol. 3578:
Laser-Induced Damage in Optical Materials: 1998
Gregory J. Exarhos; Arthur H. Guenther; Mark R. Kozlowski; Keith L. Lewis; M. J. Soileau, Editor(s)

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