Performing advanced post-CMP cleans to reduce copper detectivity and surface roughness

摘要

The effectiveness of the copper chemical-mechanical planarization (CMP) process can be improved by establishing an efficient and complete post-CMP cleaning process that reduces the roughness of the polished wafer surface and leaves the polished surface defect- and contamination-free. The cleaning process starts immediately after the barrier polish process is performed on the last platen of the CMP tool. It continues, and typically concludes, in a scrubber module. The chemistry used in these process steps can both reduce the roughness of the polished wafer surface and have a major impact on defec-tivity levels. This article focuses on studies that were performed to determine the optimal cleaning-chemical treatments for reducing surface roughness and defect levels.