Performance analysis of pixelated source-mask optimization for optical microlithography

The optical lithography is facing great challenge from the continuous shrinkage of the technology node. As one of the promising techniques, the free-form source-mask optimization (SMO) has been increasingly explored in recent years with great interests in the performance of SMO on its process robustness. In this paper, a free-form SMO framework is proposed, and its performance is tested by comparing the process window of SMO and the mask-only optimization.