Layout pattern modification method

A computer-implemented method of layout pattern modification, comprising the following steps:

• step 1:
• performing, by a processor, an optical proximity correction (OPC) process on a layout containing a plurality of square patterns to obtain a plurality of post-OPC patterns in correspondence with the plurality of square patterns;
• step 2:
• performing, by the processor, a check of a manufacturing rule on each of the plurality of post-OPC patterns to identify, from the plurality of post-OPC patterns, one or more post-OPC patterns violating the manufacturing rule;
• step 3:
• rotating at least one of the one or more post-OPC patterns violating the manufacturing rule;
• and
• step 4:
• performing, by the processor, a check of the manufacturing rule on each of the rotated and non-rotated post-OPC patterns, if no post-OPC pattern violating the manufacturing rule is identified, finishing the OPC process;
• otherwise, if one or more post-OPC patterns violating the manufacturing rule are identified, continuing to perform step 3 and step 4.