OPC to improve lithographic process window

摘要

Optical Proximity Correction (OPC) has become an indispensable tool used in deep sub-wavelength lithographic processes. OPC has been quite successful at reducing the linewidth dispersion across a product die, and also improving the overlapping process window of all printed features. This is achieved solely by biasing the mask features such that all print on target at the same dose. Recent advances in process window modeling, combined with highly customizable simulation and correction engines, have enabled process-aware OPC corrections. Building on these advances, the authors will describe a fast Process Window OPC (PWOPC) technique. This technique results in layouts with reduced sensitivity to defocus variations, less susceptibility to bridging and pinching failures, and greater coverage of over/underlying features (such as contact coverage by metal).