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Proceedings Paper

Effect of argon and non-argon ion impingement on the stress reduction of multilayers for extreme-ultraviolet lithography
Author(s): Masayuki Shiraishi; Wakana Ishiyama; Noriaki Kandaka; Tetsuya Oshino; Katsuhiko Murakami
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Paper Abstract

We investigated the effects of oxygen and nitrogen atoms on stress reduction in low-stress multilayers developed by us. It was considered that the presence of non-argon atoms in molyndenum layers caused the stress change in the multilayers, because in the ion-beam polishing (IBP) of low-stress multilayers, we found that air was mixed with the argon gas for IBP with an assisting ion source. We analyzed the composition of the low-stress multilayer with oxygen- and nitrogen-mixed gas in the depth direction and detected oxygen and nitrogen atoms near the surface of the molybdenum layers. We also used an in situ stress monitoring system developed by us and investigated the contribution to stress reduction of each process with/without oxygen and nitrogen. We found that there were thresholds for both oxygen gas flow rate and thickness oxygen-doped molybdenum layers (i.e., molybdenum oxide layers) to suppress the compressive stress change in silicon layers. It was considered that the molybdenum oxide layers functioned as barrier layers to impede the formation of the interdiffusion layers causing strain, resulting in the suppression of the compressive stress change in subsequent silicon layers.

Paper Details

Date Published: 1 July 2002
PDF: 11 pages
Proc. SPIE 4688, Emerging Lithographic Technologies VI, (1 July 2002); doi: 10.1117/12.472329
Show Author Affiliations
Masayuki Shiraishi, Nikon Corp. (Japan)
Wakana Ishiyama, Nikon Corp. (Japan)
Noriaki Kandaka, Nikon Corp. (Japan)
Tetsuya Oshino, Nikon Corp. (Japan)
Katsuhiko Murakami, Nikon Corp. (Japan)


Published in SPIE Proceedings Vol. 4688:
Emerging Lithographic Technologies VI
Roxann L. Engelstad, Editor(s)

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