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Proceedings Paper

Photomask etch and profile control of 65nm chromeless phase lithography masks using scanning probe metrology
Author(s): Scott A. Anderson; Alex Buxbaum; Ajay Kumar; Ibrahim Ibrahim
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Paper Abstract

The demands on photomask pattern transfer become tighter with every advancing technology node. Transferring patterns with feature sizes below 200nm threaten to limit lithography capabilities and prohibit the extension of current 248nm and 193nm lithography techniques. One demand that jeopardizes the current technology is the degradation of line resolution at the smaller features sizes. Transferring patterns smaller than the lithography wavelength can distort the image at the wafer. One of the resolution enhancement techniques (RET) for improving this performance and extending the lifetime of current lithography methodology is chromeless phase lithography (CPL). In this work chromeless phase lithography masks have been etched using the Tetra II Photomask Etch System. Process development of the CPL etch process is discussed with emphasis on etch depth uniformity and CD profile. Effects of varying process parameters on etch performance are discussed for a typical low load patterned mask showing excellent etch uniformity range and reactive ion etch (RIE) lag. The requirements for uniformity range and RIE lag performance (both typically < 1%) require Z-depth precision on the order of the 0.25nm provided by the SNP. Non destructive CD profiling capability of the SNP is used to show the vertical sidewall etch performance. The ability to eliminate micro-trenching while maintaining excellent phase range and RIE lag is demonstrated. The capability of the Tetra II Photomask etch system to undercut the chrome hard mask during quartz etch is also demonstrated.

Paper Details

Date Published: 28 June 2005
PDF: 10 pages
Proc. SPIE 5853, Photomask and Next-Generation Lithography Mask Technology XII, (28 June 2005); doi: 10.1117/12.617206
Show Author Affiliations
Scott A. Anderson, Applied Materials, Inc. (United States)
Alex Buxbaum, FEI Co. (United States)
Ajay Kumar, Applied Materials, Inc. (United States)
Ibrahim Ibrahim, Applied Materials, Inc. (United States)

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

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