Patent ID: 7681166

Claim:
A computer-executed method for performing dummy fill in a design layout to achieve a target density that is within a narrow range of target densities, the method comprising: receiving a low target density and a high target density which define a narrow range of target densities; receiving a design layout that includes a region whose density is less than the low target density, but whose density is increasable by placing dummy shapes which require assist features and optical proximity corrections to print properly; receiving a set of dummy-fill cells which is used to place a dummy-fill array to fill an arbitrarily sized rectangle, and which includes assist features and optical proximity corrections to obviate the need for performing assist feature placement and optical proximity correction on the dummy fill array; determining, by one or more computers, a polygon in the design layout to fill with dummy-fill cells; fracturing the polygon into a set of rectangles; and using the set of dummy-fill cells to place a first dummy-fill array in the design layout that fills a first rectangle in the set of rectangles.