Patent ID: 7794899

Claim:
A method of generating design data for a photo mask formed with patterns to be transferred to a substrate using an exposure apparatus, the method comprising: providing pattern data having a pattern row in which three or more hole patterns are arranged in one direction; executing a resizing process and a differentiating process on the hole patterns to generate an assist pattern, the longitudinal length of the assist pattern being equivalent to or larger than the length of the pattern row in one direction, the longitudinal direction of the assist pattern being substantially parallel with the one direction, the assist pattern being not transferred to the substrate; and merging the pattern data with the assist pattern to create the design data, wherein lights transmitted through the respective hole patterns are in phase, the assist pattern includes a first assist pattern for which transmitted light is in phase with the lights transmitted through the hole patterns and a second assist pattern which is located between the first assist pattern and the hole pattern and for which transmitted light is 180° out of phase with the lights transmitted through the hole patterns.