Patent ID: 8264535

Claim:
A method for analyzing a group of at least two masks for photolithography, wherein each of the masks comprises a substructure of a total structure, which is to be introduced in a layer of a wafer in a lithographic process by introducing the substructures in sequence in the layer of the wafer, wherein a first aerial image of a first one of the at least two masks is recorded, digitized and stored in a data structure; a second aerial image of a second one of the at least two masks is recorded, digitized and stored in a data structure, in which the first and second aerial images are recorded with different illumination settings; a combination image is generated from the data of the first and second aerial images, and the combination image is represented and/or evaluated, wherein: the data of the first and second aerial images are added pixel by pixel to form the combination image, and the data of the combination image are modified by photoresist simulation, wherein the data of the combination image are subjected to folding with a Gaussian function in a first step and to a threshold function in a second step, so that the modified data correspond to a developed photoresist image on the layer of the wafer.