Monte-Carlo-Based Automatic Design of Chromeless Phase Shift Mask

The optical proximity effect correction algorithm (OPERA) program based on the Monte-Carlo method has been used for optical proximity correction (OPC) and phase shift mask (PSM) generation for low-NA projection lithography systems. To apply OPERA to high-NA systems, we adopted an imaging model based on a vector diffraction theory. Also, we developed a new convergence algorithm that does not reduce the degree of freedom and prevents the convergence process from falling into a local minimum. The new program, OPERA-V, is at least 10 times faster than the previous version. OPERA-V not only improves the computation time of traditional OPC, but can also be used as an automatic design tool for creating chromeless PSMs.