The present disclosure is directed generally to a method and apparatus for monitoring mask process impact on lithography performance. A method including receiving a physical wafer pattern according to a mask, extracting a mask contour from the mask, and extracting a deconvolution pattern based on the mask contour. A lithography process is simulated to create a virtual wafer pattern based on the deconvolution pattern. The virtual wafer pattern is then compared to the physical wafer pattern.