Mask decomposition for double dipole lithography

Abstract

Method and apparatus for generating a pair of layouts suitable for forming exposure mask to use in a double dipole lithographic process are disclosed. With some implementations, a y-dipole layout and an x-dipole layout are generated by decomposing a target layout. Subsequently, an optical proximity correction process is implemented on the y-dipole layout and the x-dipole layout. The decomposition may designate ones of the edge segments in the target layout at major edge segments and other ones of the edge segments as minor edge segments. A higher feedback value may then be assigned to the minor edges than the major edges. Subsequently, a few iterations of an optical proximity correction process that utilizes a smaller than intended mask rule constraint value and the assigned feedback values is implemented on the target layout. The minor edges separated by a distance of less than the intended mask rule constraint distance are then collapsed. After which, a few iterations of the optical proximity correction process are allowed to iterate. In further implementations, once the y-dipole and x-dipole layouts have been generated. An additional optical proximity correction process is implemented on the layouts. During this optical proximity correction process, a higher feedback values is again assigned to the minor edge segments. At a point during the optical proximity correction process, minor edges within portions of the layouts that have a bias value larger than a predetermined value are expanded back from their collapsed position.