Sidelobe correction for attenuated phase shift masks

摘要

A method and system for simply and efficiently correcting sidelobe formation is disclosed. The method for reducing sidelobe formation in an aerial image created from an attenuated phase shift mask used in photolithography includes the steps of: a) generating a density map for an input design having a set of nodes identified as being outside of a periphery of the input design; b) examining the aerial image using the density map to compare an image intensity of the aerial image at a plurality of locations, each location corresponding to one node of the set of nodes; c) marking a node of the density map when the image intensity at the corresponding location of the aerial image satisfies a threshold intensity criterion and a separation distance criterion to create a set of marked nodes; and d) masking each node of the set of marked nodes.