Optical lithography simulation using wavelet transform

Optical lithography is an indispensible step in the process flow of design for manufacturability (DFM). Optical lithography simulation is a compute intensive task and simulation performance, or lack thereof can be a determining factor in time to market. Thus, the efficiency of lithography simulation is of paramount importance. Coherent decomposition is a popular simulation technique for aerial imaging simulation. In this paper, we propose an approximate simulation technique based on the 2D wavelet transform and use a number of optimization methods to further improve polygon edge detection. Results show that the proposed method suffers from an average error of less than 5% when compared with the coherent decomposition method. The benefits of the proposed method are (i) >10X increase in performance and more importantly (ii) it allows very large circuits to be simulated while some commercial tools are severely capacity limited. Approximate simulation is quite attractive for layout optimization where it may be used in a loop and may even be acceptable for final layout verification.