Illumination optimization with actual information of exposure tool and resist process

摘要

A solution tool to optimize exposure tool functions has been developed. Shown are examples of pattern matching, maximizing ED-window or NILS considering several patterns simultaneously, and so on. From these results, the following conclusions have been derived. Pattern matching whose accuracy less than 1nm can be attained flexibly by tuning illumination. Ideal illumination for hole patterns through pitches are shown and the results are sensitive to setting of exposure latitude of ED-window. Evaluation conditions such as evaluated locations and their numbers have impact on the optimization results. An optimized illumination of a device pattern varies according to k1 factor. And it is important to apply OPC during illumination optimization in case of optimizing several patterns. A model of resist simulation created by an exposure condition should be available for various exposure conditions during optimization. For this purpose an image log slope and a pattern curvature have strong impact among various characteristics of optical image.