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.