US Patent 8716841 Photolithography mask and process

A photolithography mask and method includes receiving a layout of an integrated circuit including main pattern elements, inserting an array of dummy pattern elements between and around the main pattern elements, analyzing a diffraction spectrum of at least one of the main pattern elements and the array of dummy pattern elements, and varying one or more of a first pitch between corresponding features of dummy pattern elements adjacent to each other in a first direction and a second pitch between corresponding features of dummy pattern elements adjacent to each other in a second direction based on the analyzed diffraction spectrum to form a modified array of dummy pattern elements. The diffraction spectrum of the modified array of dummy pattern elements and the main pattern elements is more diffuse than a diffraction spectrum of a corresponding array of dummy pattern elements in which neither the first nor second pitch are varied and the main pattern elements.