Illumination-source shape definition in optical lithography

摘要

A method and system are described for determining lithographic processing conditions for a lithographic process. After obtaining input, a first optimization is made for illumination source and mask design under conditions of allowing non-rectangular sub-resolution assist features. Thereafter, mask design is optimized in one or more further optimizations for which only rectangular sub-resolution assist features are allowed. The latter results in good lithographic processing while limiting the complexity of the mask design.