18 March 2015 Impacts of post OPC shapes on pattern
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As feature size get smaller, it's crucial to gain depth of focus (DOF) common window in optical lithography. In addition to the DOF of individual patterns, the shift of the best focus between various patterns is significant reducing the common DOF. High-order spatial frequencies diffracted from sharp corners and small patterns on the mask induce additional phase terms and can shift the best focus significantly. We analyzed the correlation between the pattern shape after OPC correction and its corresponding DOF, and found that more complicated shapes lead to more focus shift. Wafer experiment and simulation confirm the predictions. This provides another index for future OPC application.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
W. H. Chu, W. H. Chu, Y. T. Tsai, Y. T. Tsai, S. Y. Huang, S. Y. Huang, C. C. Kuo, C. C. Kuo, H. T. Lin, H. T. Lin, "Impacts of post OPC shapes on pattern", Proc. SPIE 9426, Optical Microlithography XXVIII, 94261S (18 March 2015); doi: 10.1117/12.2087531; https://doi.org/10.1117/12.2087531

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