Patent ID: 7725872

Claim:
A computer-implemented method of generating masks for printing a pattern on a substrate utilizing dipole illumination comprising a first and a second polar illumination component, said method comprising the steps of: identifying background areas in said pattern that do not contain any features to be imaged on said substrate; generating a vertical component mask based on said pattern to be exposed by said first polar illumination component, said vertical component mask comprising a plurality of first flare-reduction features in said background areas; and generating a horizontal component mask based on said pattern to be exposed by said second polar illumination component, said horizontal component mask comprising a plurality of second flare-reduction features in said background areas, wherein each of said first and second flare-reduction features have sub-resolution dimensions such that they do not print on said substrate, said first and second flare-reduction features being adapted to significantly reduce negative effects of lens flare and thereby improve imaging performance of printing said pattern, and wherein one or more of the above steps are implemented by a computer.