Patent ID: 8015511

Claim:
A method of making mask shape adjustment, the method comprising: creating a first mask shape; identifying one or more mask segments of said first mask shape as candidate mask segments of needing segment adjustment; applying an optical proximity correction (OPC) process, by using a computer, to said first mask shape, said OPC process identifying at least one of said candidate mask segments as a constrained mask segment; applying a rotational adjustment to said constrained mask segment; and creating a second mask shape having said constrained mask segment being rotationally adjusted, wherein applying said rotational adjustment to said constrained mask segment comprises splitting said constrained mask segment into two new mask segments having a common end point at a middle of said constrained mask segment; moving said common end point outwards, normal to said constrained mask segment, to cause said two new mask segments to expand and rotate in opposite directions, said two new mask segments forming a triangle shape with said constrained mask segment before splitting.