Method to eliminate side lobe printing of attenuated phase shift

Abstract

A computer implemented method that uses a full integrated circuit (IC) chip design, to be printed by an attenuated phase shift mask, as an input parameter. Each feature environment within the input full IC chip design is individually simulated to determine how the features within the environment would be printed from the mask created according to the input design. The simulation of each environment also determines the extent and locations of unwanted side lobes that would also be printed from the mask. Once the side lobes are determined, auxiliary features are incorporated into the input design so that the auxiliary features will become transparent openings within a mask created in accordance with the modified input design. Each auxiliary feature opening is placed at a side lobe location and is designed to eliminate the side lobe by passing radiant energy that is 180 degrees out of phase with the radiant energy of the side lobe. Thus, each auxiliary feature serves as a side lobe inhibitor when incorporated into the mask. The modified input design undergoes a proximity correction to ensure that features of each environment print as originally desired. Once corrected, each environment is simulated again to verify that its features will print as originally desired and without side lobes. Once verified, the modified input design is used to create an attenuated phase shift mask that prints the desired features, but does not print side lobes.