Optimization of polarization aberration for NA1.35 lithographic projection optical system

In order to obtain high imaging quality of numerical aperture(NA)1.35 lithographic projection optical system, except for controlling the wavefront aberration, the polarization aberration also should be optimized during design process. The polarization aberration of NA1.35 lithographic projection optical system was expressed by the use of Jones pupils and physical pupils, and the magnitude of polarization aberration was analyzed with bi-attenuation and retardation. According to the max incident angles of different optical surfaces, corresponding coatings of each optical surface were designed to optimize polarization aberration of optical system. After optimizing coatings, the diattenuation and retardation of NA1.35 lithographic projection optical system decrease to 0.021 8 and 0.057 2 rad separately compared with regular coatings, it means that the polarization aberration of optical system decreases. Using lithographic simulation software Prolith to simulate the lithography performance with regular coatings and optimized coatings separately, the result shows that the image contrast with optimized coatings increases 4.4%, proving the effectiveness of the method for optimizing polarization aberration of NA1.35 lithographic projection optical system.