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Journal of Micro/Nanolithography, MEMS, and MOEMS

Influence of resist blur on ultimate resolution of ArF immersion lithography
Author(s): Tokuyuki Honda; Yasuhiro Kishikawa; Yuichi Iwasaki; Akinori Ohkubo; Miyoko Kawashima; Minoru Yoshii
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Paper Abstract

The chemical amplification provides high sensitivity of resists for deep-uv and extreme-uv (EUV) lithography. On the other hand, the chemical amplification involves photoacid diffusion that causes contrast degradation of the latent image or, in other words, resist blur. We study the influence of the resist blur in high–numerical aperture ArF immersion lithography by using an interferometric exposure tool. The contrast ratio between the resist latent image and the original aerial image was measured for half pitches from 45 to 80 nm. Acid diffusion length for a high-resolution ArF resist was determined as 11 nm in sigma (26 nm in full width at half maximum) assuming a Gaussian blur kernel. The results revealed that the influence of the resist blur is a significant issue for the 45-nm half-pitch node. The reduction of acid diffusion length is highly desirable. Given the tradeoff between the resist resolution and sensitivity, increasing illumination intensity in exposure tools can be an effective means to overcome the challenge of the resist blur. We also demonstrate resist imaging of 30-nm line-and-space pattern with a high-index fluid. While our focus is on ArF immersion lithography, our findings are also relevant to EUV lithography.

Paper Details

Date Published: 1 October 2006
PDF: 6 pages
J. Micro/Nanolith. 5(4) 043004 doi: 10.1117/1.2397018
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 5, Issue 4
Show Author Affiliations
Tokuyuki Honda, Canon Inc. (Japan)
Yasuhiro Kishikawa, Canon Inc. (Japan)
Yuichi Iwasaki, Canon Inc. (Japan)
Akinori Ohkubo, Canon Inc. (Japan)
Miyoko Kawashima, Canon Inc. (Japan)
Minoru Yoshii, Canon Inc. (Japan)


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