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Proceedings Paper

A hyper-NA projection lens for ArF immersion exposure tool
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Paper Abstract

Resolution enhancement in ArF dry lithography is limited by the numerical aperture (NA), which cannot be extended past the physical limit of 1.0. Immersion lithography is proposed as a candidate to overcome this limitation as resolution can be enhanced with a hyper-NA immersion projection lens. In addition, depth of focus (DOF) can be extended owing to the small incident angle for marginal rays onto the image plane. Our development of immersion optics can be divided into three phases. First, the initial evaluation has successfully been conducted in the engineering evaluation tool (EET), in which the projection optics is converted from dry-use to wet-use while retaining the same NA, 0.85. Second, the projection optics with 1.07NA has been developed aiming at devices with 50-55nm half-pitch (hp) patterns. The optics, comprising only the refractive elements, is exclusively dedicated to immersion usage. Third, catadioptric optics with 1.3NA targeting at 45nm hp devices is intensively studied. This paper will focus on the second and the third phases of the development.

Paper Details

Date Published: 15 March 2006
PDF: 8 pages
Proc. SPIE 6154, Optical Microlithography XIX, 615421 (15 March 2006); doi: 10.1117/12.656083
Show Author Affiliations
Hironori Ikezawa, Nikon Corp. (Japan)
Yasuhiro Ohmura, Nikon Corp. (Japan)
Tomoyuki Matsuyama, Nikon Corp. (Japan)
Yusaku Uehara, Nikon Corp. (Japan)
Toshiro Ishiyama, Nikon Corp. (Japan)

Published in SPIE Proceedings Vol. 6154:
Optical Microlithography XIX
Donis G. Flagello, Editor(s)

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