Retention of a polishing pad on a platen

Abstract

A polishing pad is retained on a platen by structures which do not require adhesive. In one embodiment, a polishing pad has a top polishing surface and an undersurface. The undersurface has a surface profile which is configured to interfit with a complementary surface profile on a platen. The surface profile of the undersurface may comprise an array of parallel ridges and grooves.

Description

[0001] 1. Field of the Invention[0002] The invention relates to device and method for securing a polishing pad on a platen of a polishing apparatus.[0003] 2. Discussion of Related Art[0004] Polishing pads for removing material from the surface of a workpiece are well-known. A typical polishing pad is a relatively thin, disk-shaped article that is mounted on a platen of a polishing machine. The polishing pad is generally secured to the platen by a pressure sensitive adhesive that is laminated on the back side of the polishing pad.[0005] The pressure sensitive adhesive has a number of disadvantages. First, as the polishing pad is placed on the platen, bubbles of air tend to get trapped between the adhesive and the platen. Any trapped air will distend the relatively thin polishing pad, thereby causing raised areas or bulges in the polishing surface of the polishing pad. These bulges cannot be eliminated by forcing the air bubbles out from under the pad with a roller. Instead, the bulge...

AI Technical Summary

Problems solved by technology

First, as the polishing pad is placed on the platen, bubbles of air tend to get trapped between the adhesive and the platen.

Any trapped air will distend the relatively thin polishing pad, thereby causing raised areas or bulges in the polishing surface of the polishing pad.

These bulges cannot be eliminated by forcing the air bubbles out from under the pad with a roller.

This is a time-consuming process, and some small bulges often go undetected and remain in the polishing surface.

Any bulges in the polishing surface will generate non-uniformities on the polished surface of the workpiece, thereby causing defects in the polished surface.

Another problem associated with the adhesive is that considerable force is required to pull a used polishing pad up from the platen for replacement, which work leads to strain injury to personnel.

Also, adhesive residue normally remains on the platen after the old polishing pad is pulled off.

Removing the residue is a time-consuming process which exposes personnel to potential chemical hazards.

Another problem is that the adhesive may release sodium and other ion bearing elements which interfere with semiconductor processing.

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