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Proceedings Paper

Quartz etch process for alternating aperture phase shift masks (alt-APSM)
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Paper Abstract

The quartz dry etch is a critical step in the manufacture of Alternating Aperture Phase Shift masks (alt-APSM). In order to maintain uniform phase shift across the mask, the etch depth uniformity has to be strictly controlled. Both the radial and linear components of non-uniformity have to be minimized. The Mask Etcher IV developed at Unaxis USA reduces both the components of non-uniformity using unique hardware adjustments. Using a fluorocarbon based chemistry, etch depth variations between different feature sizes is also minimized. With good etch depth linearity, phase shift does not vary with feature size. To achieve this, etched quartz structures need to have good selectivity to resist / chrome and vertical sidewalls. Etch depth uniformity was measured using an n&k1700 RT and etch depth linearity was measured using an AFM. Etched quartz structure morphologies are observed using a SEM. After preliminary screening experiments, an optimized hardware suite and process conditions that produce good etch depth uniformity, linearity and quartz profiles with vertical sidewalls and minimum microtrenching is determined.

Paper Details

Date Published: 28 June 2005
PDF: 6 pages
Proc. SPIE 5853, Photomask and Next-Generation Lithography Mask Technology XII, (28 June 2005); doi: 10.1117/12.617095
Show Author Affiliations
Sunil Srinivasan, Unaxis USA (United States)
Russ Westerman, Unaxis USA (United States)
Jason Plumhoff, Unaxis USA (United States)
Dave Johnson, Unaxis USA (United States)
Chris Constantine, Unaxis USA (United States)

Published in SPIE Proceedings Vol. 5853:
Photomask and Next-Generation Lithography Mask Technology XII
Masanori Komuro, Editor(s)

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