1 January 2009 Influence of resist blur on resolution of hyper-NA immersion lithography beyond 45-nm half-pitch
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Abstract
For lithography of 45-nm half-pitch and beyond, the resist blur due to photoacid diffusion is a significant issue. On the other hand, it has been generally recognized that there is a trade-off between resist resolution and sensitivity. We study the influence of the resist blur on resolution in hypernumerical 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 nm to 9 nm in sigma assuming Gaussian blur kernel. In addition, we found that the acid diffusion length, which is directly related to the resist resolution and is controllable by photoacid generator (PAG) anion size, polymer resin size, and post-exposure bake (PEB) temperature. We confirmed that there is a trade-off between resist resolution and sensitivity. Our results indicate that the resist blur is still a concern in order to extend lithography for 45 nm 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.
© (2009) Society of Photo-Optical Instrumentation Engineers (SPIE)
Minoru Yoshii, Minoru Yoshii, Yasuhiro Kishikawa, Yasuhiro Kishikawa, Yuichi Iwasaki, Yuichi Iwasaki, Akinori Ohkubo, Akinori Ohkubo, Miyoko Kawashima, Miyoko Kawashima, Seiji Takeuchi, Seiji Takeuchi, Tokuyuki Honda, Tokuyuki Honda, Toyohiko Yatagai, Toyohiko Yatagai, } "Influence of resist blur on resolution of hyper-NA immersion lithography beyond 45-nm half-pitch," Journal of Micro/Nanolithography, MEMS, and MOEMS 8(1), 013003 (1 January 2009). https://doi.org/10.1117/1.3059551 . Submission:
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