Chemical mechanical polishing pads having a consistent pad surface microtexture

Abstract

The present invention provides pre-conditioned chemical mechanical (CMP) polishing pads comprising a polymer, preferably, a porous polymer having a pad surface microtexture effective for polishing having a series of visibly intersecting arcs on the polishing layer surface, the intersecting arcs having a radius of curvature equal to or greater than half of the radius of curvature of the pad and extending all the way around the surface of the pad in radial symmetry around the center point of the pad wherein the resulting CMP polishing pad has a surface roughness of from 0.01 μm to 25 μm, Sq. The CMP polishing pads may be made by methods comprising grinding the surface of a CMP polishing pad with a rotary grinder to form the surface microtexture.

Description

[0001]The present invention relates to chemical mechanical polishing (CMP) pads having a consistent pad surface microtexture. More particularly, the present invention relates to CMP polishing pads having a CMP polishing layer of one or more polymer, preferably, a porous CMP polishing layer, having a radius, and having a surface roughness of at least 0.01 μm to 25 μm, Sq, or, preferably, from 1 μm to 15 μm, Sq, and having a series of visibly intersecting arcs on the polishing layer surface and having a radius of curvature equal to or greater than half, preferably, equal to half the radius of curvature of the polishing layer.[0002]The manufacture of polishing pads for use in chemical mechanical planarization is known to include the molding and curing of a foamed or porous polymer in a mold having the desired diameter of the final polishing pad, such as a polyurethane, followed by demolding and cutting the cured polymer in a direction parallel to the top surface of the mold to form a l...

AI Technical Summary

Benefits of technology

The patent is about a process called conditioning, which is like buffing for chemical mechanical polishing. The process involves using a rotary abrasive wheel with a surface like fine sandpaper to improve the efficiency of polishing. The conditioning helps to make the pad ready for use right away without a break in period. The technical effect of this patent is to provide a pre-conditioned pad for polishing without the need for a break in period.

Problems solved by technology

These methods have limited capability to achieve a consistent pad surface microtexture required for low defectivity in polished substrates and uniform removal of material from substrates.

In fact, the methods generally create a visible design, such as grooves of a given width and depth and a visible but inconsistent texture.

For example, a skiving process is unreliable for pad surface shaping because the stiffness of the mold changes with mold thickness and the skiver blade continuously wears.

Single point facing techniques have been unable to yield a consistent pad surface microtexture due to continuous tooling wear and lathe positioning accuracy.

Pads made by injection molding processes lack uniformity owing to inconsistent material flow throughout the mold; further, the moldings tend to distort as the pad sets and cures because the curative and the remainder of the molded material can flow at different rates during injection into a confined area, especially at elevated temperatures.

Unfortunately, while the methods of West et al. can smooth a pad, they do not provide a consistent pad surface microtexture and cannot be used to treat in a softer pad (Shore D hardness according to ASTM D2240-15 (2015) of pad or pad polymer matrix of 40 or less).

Further, the West et al. methods remove so much material that the useful life of the resulting polishing pads may be adversely affected.

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