Patent ID: 9009633
Filing Date: 2015-04-14
Classification: G03F,G06F

Abstract:
1. A method of correcting assist features, comprising: receiving a first layout pattern by a computer system; splitting the first layout pattern into a plurality of first regions; adding a plurality of assist features into the first layout pattern to form a second layout pattern, and defining at least one of the assist features neighboring any one of the edges of the first regions as a selected pattern in the first regions of the first layout pattern and also in the second layout pattern; splitting the second layout pattern into a plurality of second regions, wherein the second regions are larger than the first regions; performing a check step on the region of the second regions that contains the selected pattern, wherein the check step comprises checking if the selected pattern obeys the rules of process rule check (PRC) of assist features; correcting the second layout pattern to form a corrected second layout pattern; performing at least an optical proximity correction (OPC) on the corrected second layout pattern to form a corrected first layout pattern and a plurality of corrected assist features; outputting the corrected first layout pattern and the corrected assist features onto a mask; and performing a lithography process on a material layer through the mask to form the first layout pattern in the material layer.