Abstract: A method for determining a mask pattern is described. During the method, a first mask pattern that includes a plurality of second regions corresponding to the first regions of the photo-mask is provided. Then, a second mask pattern is determined based on the first mask pattern and differences between a target pattern and an estimate of a wafer pattern that results from the photolithographic process that uses at least a portion of the first mask pattern. Note that the determining includes different treatment for different types of regions in the target pattern, and the second mask pattern and the target pattern include pixilated images.

Abstract: A method for verifying a lithographic process is described. During the method, a set of guard bands are defined around a target pattern that is to be printed on a semiconductor die using a photo-mask in the lithographic process. An estimated pattern is calculated using a model of the lithographic process. This model of the lithographic process includes a mask pattern corresponding to the photo-mask and a model of an optical path. Then, whether or not positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands is determined.