Application of an Effective Wavelet Matrix Transform Approach for Optical Lithography Simulation: Analysis of Topological Effects of Phase-Shifting Masks

초록

In this paper, the boundary element method (BEM) is newly applied to the numerical simulation of an optical lithography, and also is combined with the wavelet matrix transform approach in order to resolve the disadvantage of BEM. Though the impedance matrix derived from the boundary element formulation is usually unsymmetric and fully populated with non-zero elements, the combination of two methods transforms it into the highly sparse matrix, which can be solved efficiently by a sparse solver. The proposed method is implemented for analyzing the topological effect of two-dimensional phase-shifting masks, and their results are compared with those of the waveguide method (i.e. rigorous coupled wave analysis). From the comparison, it is confirmed that the proposed method would be more efficient than the methods based on either BEM itself or the waveguide method in views of the convergence, the accuracy, the calculation time and the usage of computer memory.