Abstract: A method integrating target optimization and optical proximity correction including: fragmenting sides of a target pattern in the metal layer to form a plurality of fragments; simulating the target pattern and calculating image log slope of each fragment; calculating a target pattern optimal parameter for each fragment which is a product of three parameters including the image log slope, overlap ratio of the target pattern and a via pattern in a via layer, and critical dimension; optimizing the target pattern based on the target pattern optimal parameter; preforming optical proximity correction to the optimized target pattern; determining whether the corrected target pattern meets requirements; if yes, ending the target optimization and optical proximity correction; otherwise, using the corrected target pattern as a current target pattern and iterate from the step of simulating the target pattern and calculating image log slope of each fragment.