Image Process Method to Improve Mask Inspection Performance

The present disclosure relates to a method of inspecting a photomask to decrease false defects, which uses a plurality of image rendering models with varying emphasis on different design aspects, and an associated apparatus. In some embodiments, the method is performed by forming an integrated circuit (IC) design comprising a graphical representation of an integrated circuit. A first image rendering simulation is performed on the IC design using an initial image rendering model to determine a plurality of initial mask defects. A second image rendering simulation is performed on the IC design using a modified image rendering model that emphasizes a design aspect to determine a plurality of modified mask defects. By comparing the plurality of initial mask defects with the plurality of modified mask defects, falsely identified mask defects can be detected and eliminated.