Minimizing mask complexity for advanced optical lithography

The extension of optical lithography to ever deeper sub-wavelength feature sizes has led to an alarming increase in photo-mask complexity and associated cost. Changes in design philosophy can play a key role in mitigating this trend. We propose the introduction of a new optimization cycle early in the physical design process based on minimizing pattern complexity. We study the use of a pattern complexity metric based on Fourier coding to accomplish such an optimization. The ultimate goal is simplification of resolution enhancement technology (RET) methods required for a given design and the generation of a correspondingly simpler and more cost effective mask set.