Source mask optimization for extreme-ultraviolet lithography based on thick mask model and social learning particle swarm optimization algorithm

Extreme ultraviolet (EUV) lithography plays a vital role in the advanced technology nodes of integrated circuits manufacturing. Source mask optimization (SMO) is a critical resolution enhancement technique (RET) or EUV lithography. In this paper, an SMO method for EUV lithography based on the thick mask model and social learning particle swarm optimization (SL-PSO) algorithm is proposed to improve the imaging quality. The thick mask model's parameters are pre-calculated and stored, then SL-PSO is utilized to optimize the source and mask. Rigorous electromagnetic simulation is then carried out to validate the optimization results. Besides, an initialization parameter of the mask optimization (MO) stage is tuned to increase the optimization efficiency and the optimized mask's manufacturability. Optimization is carried out with three target patterns. Results show that the pattern errors (PE) between the print image and target pattern are reduced by 94.7%, 76.9%, 80.6%, respectively. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This paper introduces an EUV lithography SMO method based on the thick mask model and SL-PSO algorithm, which effectively improves imaging quality and reduces pattern errors.