8 August 1993 Effect of duty ratio of line and space in phase-shifting lithography
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This paper discusses the effect of duty ratio of line and space patterns and the coherency of illumination for the projection system on the lithographic characteristics, which must be taken into consideration in designing LSI patterns with an alternated type phase-shifting method. It was found that the alternated phase-shifting method improved the DOF for space patterns using a width smaller than the line width. On the contrary, there was no effect for narrow line patterns when the space width was larger than twice the line width. It was also found that the DOF became larger, when the coherency became higher using both the alternated and the conventional mask for line patterns having a width smaller than the space width. It is concluded that a high coherency must be chosen for the phase-shifting method.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Junji Miyazaki, Junji Miyazaki, Atsumi Yamaguchi, Atsumi Yamaguchi, Keiji Fujiwara, Keiji Fujiwara, Nobuyuki Yoshioka, Nobuyuki Yoshioka, Hiroaki Morimoto, Hiroaki Morimoto, Katsuhiro Tsukamoto, Katsuhiro Tsukamoto, "Effect of duty ratio of line and space in phase-shifting lithography", Proc. SPIE 1927, Optical/Laser Microlithography, (8 August 1993); doi: 10.1117/12.150462; https://doi.org/10.1117/12.150462

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