US Patent 7694269 Method for positioning sub-resolution assist features

The present application is directed to a method of selectively positioning sub-resolution assist features (SRAF) in a photomask pattern for an interconnect. The method comprises determining if a first interconnect pattern option will result in improved circuit performance compared with a second interconnect pattern option, where the first option is designed to be formed with SRAF and the second option is designed to be formed without SRAF. If it is determined that the first option will result in improved circuit performance, the first pattern option is selected as a target pattern and one or more SRAF patterns are positioned to facilitate patterning of the first pattern option. If it is not determined that the first option will result in improved performance, the second pattern option is selected as a target pattern.