Assist feature aware double patterning decomposition

Double patterning has gained prominence as the most likely lithographic methodology to help keep Moore's law going towards 32nm 1/2 pitch lithography. While solutions, to date, have focused mainly on gap splitting to avoid minimum spacing violations, the decomposition should, ideally, also attempt to optimize the process window of the decomposed masks. A major contributor to process window sensitivity is the correct placement of sub-resolvable assist features. These features are placed once the polygons of each mask are defined, i.e. post decomposition. If some awareness of this downstream process step is made available to the double patterning decomposition stage, then a more robust decomposition can be achieved.