SYSTEM, MASKS, AND METHODS FOR PHOTOMASKS OPTIMIZED WITH APPROXIMATE AND ACCURATE MERIT FUNCTIONS

摘要

Photomask patterns are represented using contours defined by mask functions. Given target pattern (901), contours are optimized such that defined photomask, when used in photolithographic process, prints wafer pattern faithful to target pattern. Optimization (904, 906, 908, 909) utilizes " merit function" (907) for encoding aspects of photolithographic process, preferences relating to resulting pattern (e.g. restriction to rectilinear patterns), robustness against process variations, as well as restrictions imposed relating to practical and economic manufacturabiliry of photomasks.