Yield enhancement/Productivity improvement for Sub-110nm Memory Lithography using new alignment strategy

摘要

The characteristics and performance of SPM and XPA were investigated for the sub-110 nm and below memory lithography. Various alignment strategies using SPM and XPA were compared on the production wafer for improved overlay performance. It is evident that SPM out-performs XPA for most of layers as CMP can easily over polish XPA due to the low pattern density. Based on these results, it is believed that SPM will be a promising candidate for sub-110nm memory process with better overlay performance.