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Proceedings Paper

Immersion defectivity control by optimizing immersion materials and processes
Author(s): Katsushi Nakano; Hiroshi Kato; Soichi Owa
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Paper Abstract

Volume production of 55nm node device using Nikon immersion lithography tool, S609B, has started. One very important issue for volume production immersion lithography is defectivity control. The mainstream resist process for the initial stage of immersion is to use a topcoat, because chip manufacturers can continue to use conventional resist whose lithographic properties are well characterized. On the other hand, because of its simplicity and cost effectiveness, a topcoat-less resist process is an attractive candidate for the second stage of immersion lithography. Intensive study and development of topcoat-less resist is being done by resist vendors. One unexpected benefit of topcoat-less resist is it is much easier to increase hydrophobicity than developer soluble topcoat. For defectivity analysis of both topcoat and topcoat-less process, a dedicated immersion cluster comprised of a volume production immersion exposure tool, S609B, with NA of 1.07 and a resist coater-developer LITHIUS i+ (TEL) is used. Excellent defectivity data obtained using various materials and processes are shown in this paper. Understanding the root cause of defects is very important to control them. Defect source analysis (DSA) revealed particles cause many types of defects. Interesting correlations between particles and other topcoat defects and resultant pattern defects are shown in this paper. In the immersion resist process, wafer edge condition is one key issue. Using topcoat-less resist, wafer edge condition and its defectivity dependency is discussed and analyzed.

Paper Details

Date Published: 29 March 2007
PDF: 10 pages
Proc. SPIE 6519, Advances in Resist Materials and Processing Technology XXIV, 65190D (29 March 2007); doi: 10.1117/12.711466
Show Author Affiliations
Katsushi Nakano, Nikon Corp. (Japan)
Hiroshi Kato, Nikon Corp. (Japan)
Soichi Owa, Nikon Corp. (Japan)

Published in SPIE Proceedings Vol. 6519:
Advances in Resist Materials and Processing Technology XXIV
Qinghuang Lin, Editor(s)

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