One of the critical challenges facing lithographers is how to optimize the numerical aperture (NA) and illumination source intensity and polarization distribution to deliver the maximum process window for a given design in manufacturing. While the maximum NA has topped out at 1.35, the available illuminator options continue to increase, including the eventual possibility of dynamically programmable pixelized illumination to deliver nearly any imaginable source shape profile. New approaches to leverage this capability and simultaneously optimize the source and mask shapes (SMO) on a per-design basis are actively being developed. Even with the available “standard” illumination source primitive shapes, however, there exist a huge range of possible choices available to the lithographer. We report here on the use of several analysis methods, including process variability bands, as convenient metrics to optimize full-chip post-OPC CD control in conjunction with illumination optimization tooling.

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