Patent ID: 7698665
Filing Date: 2010-04-13
Classification: G03F

Abstract:
1. A computer-implemented method of modifying a photomask pattern for producing a target pattern in a region of a photomask comprising: providing a functional representation of a first photomask pattern comprising a first plurality of values over the area of the region of the photomask; modifying the functional representation of the first photomask pattern to produce a functional representation of a second photomask pattern based, at least in part, upon a merit function for the second photomask pattern and the target pattern; wherein the functional representation of the second photomask pattern comprises a second plurality of values over the area of the region of the photomask; wherein the functional representation of the first photomask pattern is capable of being fractured into a smaller number of rectangles than the functional representation of the second photomask pattern; and wherein the functional representation of the second photomask pattern includes polygons having a smaller number of vertices than corresponding polygons in the functional representation of the first photomask pattern; and determining a functional representation of a third photomask pattern that is capable of being fractured into a smaller number of rectangles than the functional representation of the second photomask pattern; wherein the functional representation of the third photomask pattern comprises a third plurality of values over the area of the region of the photomask; and wherein a merit function over the area of the region of the photomask for the third photomask pattern and the target pattern is improved relative to a merit function over the area of the region of the photomask for the first photomask pattern and the target pattern.