Configuration design for the variable pupil shaping unit of a photolithography machine

Abstract

This work provides an integrated design and simulation method for a pupil shaping unit, which combines optical design and simulation software using the Python programming language. The novel approach presented here allows for systematic optimization and solves the inverse problem to obtain the configuration of a pupil shaping unit with given partial coherence factors (sigmas). The relationships among sigma, focal length, zoom lens separation, axicon separation, and ring width are investigated for conventional and annular illumination modes. Results of the pupil shaping unit for a NA 0.75 193 nm photolithography machine are presented, and a new interpolation table design method that simplifies the original method is proposed. The maximum residual experimental error for sigma is 0.01106.