Patent ID: 7232630

Claim:
A method for enhancing printability of a complementary mask in a sub-wavelength photolithographic process, the method comprising: receiving data corresponding to a complementary mask; wherein the complementary mask is designed for use with a phase shifting mask; wherein a pattern represented by said data of the complementary mask defines a number of openings that expose unwanted photoresist located between regions exposed via the phase shifting mask during the sub-wavelength photolithographic process; identifying from among said openings, a plurality of critical openings as being too small to print due to intensity of radiation passing therethrough being ineffective in exposing said unwanted photoresist during the sub-wavelength photolithographic process; determining a threshold intensity for radiation passing through the plurality of critical openings during the sub-wavelength photolithographic process, to be effective in erasing the unwanted photoresist; modifying at least a portion of the data representing the plurality of critical openings such that each of the plurality of critical openings will provide radiation of at least the threshold intensity during the sub-wavelength photolithographic process.