Paper
26 March 2007 Assessment of trade-off between resist resolution and sensitivity for optimization of hyper-NA immersion lithography
Yasuhiro Kishikawa, Miyoko Kawashima, Akinori Ohkubo, Yuichi Iwasaki, Seiji Takeuchi, Minoru Yoshii, Tokuyuki Honda
Author Affiliations +
Abstract
The resist blur due to photoacid diffusion is a significant issue for 45-nm half-pitch node and beyond. Furthermore, it has been generally recognized that there is a trade-off between resist resolution and sensitivity. In this paper, we study the influence of the resist blur on resolution and sensitivity in hyper-numerical aperture ArF immersion lithography by utilizing a two-beam interferometric exposure tool. We evaluated the current photoresist performance for some of the latest commercial resists, and estimated their acid diffusion lengths as 8 to 9 nm in sigma assuming Gaussian blur kernel. In addition, we found that the acid diffusion length, that is, the resist resolution was controllable by PAG anion size, polymer resin size, and PEB temperature. We also found that there was the trade-off between resist resolution and sensitivity. Our results indicated that the resist blur is still a concern in order to extend ArF lithography for 45-nm half-pitch node and beyond, however, it will not likely be a showstopper. We consider that total optimization of resists and exposure tools is important in order to achieve ultimate resolution in hyper-NA immersion lithography.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yasuhiro Kishikawa, Miyoko Kawashima, Akinori Ohkubo, Yuichi Iwasaki, Seiji Takeuchi, Minoru Yoshii, and Tokuyuki Honda "Assessment of trade-off between resist resolution and sensitivity for optimization of hyper-NA immersion lithography", Proc. SPIE 6520, Optical Microlithography XX, 65203L (26 March 2007); https://doi.org/10.1117/12.711420
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Cited by 2 scholarly publications and 43 patents.
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KEYWORDS
Diffusion

Modulation transfer functions

Photoresist materials

Immersion lithography

Polymers

Interferometry

Lithography

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