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Proceedings Paper

The next-generation ArF excimer laser for multiple-patterning immersion lithography with helium free operation
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Paper Abstract

Multiple patterning ArF immersion lithography has been expected as the promising technology to satisfy tighter leading edge device requirements. A new ArF excimer laser, GT64A has been developed to cope with the prevention against rare resource shortage and the reduction of operational costs. GT64A provides the sophisticated technologies which realize the narrow spectral bandwidth with helium free operation. A helium gas purge has usually been employed due to the low refractive index variation with temperature rises within a line narrowing module(LNM). Helium is a non-renewable resource and the world’s reserves have been running out. Nitrogen gas with an affordable price has been used as an alternative purge gas of helium on the restrictive condition of low thermal loads. However, the refractive index variation of nitrogen gas is approximately ten times more sensitive to temperature rises than that of helium, and broadens a spectral bandwidth in the high duty cycle operations. The new LNM design enables heat effect in laser shooting at optical elements and mechanical components in the vicinity of an optical path to be lower. This reduces thermal wavefront deformation of a laser beam without helium gas purge within LNM, and narrows a spectrum bandwidth without helium purge. Gigaphoton proved that the new LNM enabled E95 bandwidth without control to improve a lot with nitrogen purge.

Paper Details

Date Published: 15 March 2016
PDF: 6 pages
Proc. SPIE 9780, Optical Microlithography XXIX, 97801I (15 March 2016); doi: 10.1117/12.2218778
Show Author Affiliations
Hirotaka Miyamoto, Gigaphoton Inc. (Japan)
Takahito Kumazaki, Gigaphoton Inc. (Japan)
Hiroaki Tsushima, Gigaphoton Inc. (Japan)
Akihiko Kurosu, Gigaphoton Inc. (Japan)
Takeshi Ohta, Gigaphoton Inc. (Japan)
Takashi Matsunaga, Gigaphoton Inc. (Japan)
Hakaru Mizoguchi, Gigaphoton Inc. (Japan)

Published in SPIE Proceedings Vol. 9780:
Optical Microlithography XXIX
Andreas Erdmann; Jongwook Kye, Editor(s)

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