Techniques for assembling polishing pads for chemical-mechanical polishing of silicon wafers

摘要

A technique for mounting polishing pads to a platen in chemi- mechanical semiconductor wafer polishing apparatus is disclosed. A lower pad is mounted to the platen, and is trimmed to the size of the platen. An upper pad is mounted to the lower pad, and is sized so that an extreme outer edge portion of the upper pad extends beyond the trimmed outer edge of the lower pad. The outer edge portion of the upper pad is deformed downwardly, towards the lower pad. In this manner, polishing slurry is diverted from the pad-to-pad interface. Additionally, an integral annular lip can be formed on the front face of the upper pad, creating a reservoir for slurry to be retained on the face of the upper pad for enhancing residence time of the polishing slurry prior to the slurry washing over the face of the upper pad.