Patent ID: 8423928

Claim:
A method for decomposing a particular pattern on a layer of a design layout into multiple sub-patterns for multiple photolithographic exposure operations, the layer comprising a plurality of regions, the method comprising: receiving a region of interest comprising the particular pattern defined by a set of edges; identifying corner edges where a plurality of edge segments from the set of edges are joined together; processing the set of edges by rounding the identified corner edges of the particular pattern; demarcating the set of processed edges by defining a set of nodes that follows contours of the set of processed edges, the set of nodes comprising a set of internal edge nodes defined inside the particular pattern and a set of external edge nodes defined outside the particular pattern, the space between the internal edge nodes and external edge nodes specifying an acceptable edge placement error during pattern decomposition; specifying intensity values for the set of internal nodes and the set of external nodes, wherein the intensity value for the set of internal nodes is different than the intensity value for the set of external nodes; and by a computer, searching, based on the specified intensity values, a solution space of lithographically feasible images to identify at least two images for decomposing the particular pattern such that a union of the images closely approximates the particular pattern.