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Proceedings Paper

Optimization and scale-down of wafer-based resist strip and rinse processes for photomask production
Author(s): Brant L. Aggus; Gene Weaver
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Paper Abstract

Retrofitting of wafer processing equipment is a common scenario in the photomask industry, as most available tools are built to accommodate the high throughput and substrate size of wafers. The acid process tanks in use at most mask shops are built to suit a single rack of 25 8 inch wafers, each coated with roughly two microns of photoresist. Conversely, a typical photomask shop sends one to two masks at a time through the resist strip line, each coated with 4500 angstroms of resist. The amount of unused volume of active chemical within an 8 inch X 8.5 inch X 10 inch acid tank when it is dumped is enough to warrant a hardware change. Experimentation has shown that it is possible to decrease Piranha usage by 43 percent by optimizing tank size for photomasks. The same logic applies to quick dump rinsers (QDRs). Additionally, water is wasted with 'spray down' processes, whereby masks are sprayed via perforated bars or nozzles. Because a < 0.5 μm viscous sublayer can not be practically achieved through spraying the mask, better cleaning performance is obtained with a bottom-filled weiring process. This is demonstrated through experimental results and theoretical mass transfer models.

Paper Details

Date Published: 11 March 2002
PDF: 10 pages
Proc. SPIE 4562, 21st Annual BACUS Symposium on Photomask Technology, (11 March 2002); doi: 10.1117/12.443112
Show Author Affiliations
Brant L. Aggus, Photronics, Inc. (United States)
Gene Weaver, Photronics, Inc. (United States)

Published in SPIE Proceedings Vol. 4562:
21st Annual BACUS Symposium on Photomask Technology
Giang T. Dao; Brian J. Grenon, Editor(s)

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