Optimization of contact hole lithography for 65-nm node logic LSI

摘要

Patterning of contact/via is a difficult issue for the optical lithography for each successive generation of LSIs. We examined a number of approaches to obtain a large process window and found that a dry ArF exposure tool with a large depth of focus (DOF) can form 100 nm contact holes. Our experimental results show that enough DOF can be obtained for various layouts by using sub-resolution assist feature (SRAF) technology and a unique illumination technology.