US 5,310,455 AGranted

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

AssigneeLSI Logic Corporation

InventorsNicholas F. Pasch, Thomas G. Mallon, Mark A. Franklin

Life of this patent

Estimating the term…

Loading patent…

Abstract

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.

Claims9

Dependent claims

Method of assembling polishing pads to the platen of apparatus for chemi-mechanical polishing of semiconductor wafers, comprising:

assembling a first planar polishing pad to a platen of a chemi-mechanical polisher, the platen having an outer edge and a diameter "d";
trimming the first polishing pad so that an outer edge of the first polishing pad is coincident with the outer edge of the platen;
assembling a second polishing pad, having a front face for polishing a wafer, to the first polishing pad, the second polishing pad having a diameter "D" greater than the diameter "d" of the platen, so that an edge portion region of the second polishing pad extends beyond the periphery of the first polishing pad about the entire circumference of the first polishing pad, the front face of the second polishing pad being exposed after assembling to the first polishing pad for polishing the wafer.

Dependencies are inferred from the claim text.