One embodiment of a method for process window optimized optical proximity
correction includes applying optical proximity corrections to a design
layout, simulating a lithography process using the post-OPC layout and
models of the lithography process at a plurality of process conditions to
produce a plurality of simulated resist images. A weighted average error
in the critical dimension or other contour metric for each edge segment
of each feature in the design layout is determined, wherein the weighted
average error is an offset between the contour metric at each process
condition and the contour metric at nominal condition averaged over the
plurality of process conditions. A retarget value for the contour metric
for each edge segment is determined using the weighted average error and
applied to the design layout prior to applying further optical proximity
corrections.