Tatian polynomial-based annular pupil wavefront optimization method for high-NA extreme ultraviolet lithography

Abstract

The advanced technology node has an exact error tolerance. The effect of projection objective aberration on imaging cannot be neglected. In order to reduce the effect of aberration, considering the central obscuration of the high-NA extreme ultraviolet projection objective, we propose a Tatian polynomial-based annular pupil wavefront optimization (TBAPWO) method. An active pupil consisting of 64-term Tatian polynomials is incorporated into the imaging model. The suitable coefficients of the Tatian polynomials are solved using the gradient iteration method. The optimized active pupil can improve lithographic imaging quality. Simulation results show that the TBAPWO method can effectively reduce the pattern error of imaging by more than 30%, which indicates that the effect of aberration on imaging is controlled.