Polishing pad and polishing apparatus

Abstract

A polishing pad enables efficient removal of a polishing product and an “old polishing liquid” remaining on a surface (polishing surface) or in through-holes of a polishing pad. The polishing pad has a polishing surface and a plurality of through-holes extending in the thickness direction, which communicate with each other by communication grooves. The through-holes have a diameter of, e.g., 2 to 5 mm. The aperture ratio of the through-holes is, e.g., 10 to 50% of the surface area of the polishing surface of the polishing pad. The depth of the communication grooves is, e.g., 40 to 60% of the thickness of the polishing pad. The width of the communication grooves is, e.g., 10 to 50% of the diameter of the through-holes.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a polishing pad and a polishing apparatus, and more particularly to a polishing pad useful for polishing an interconnect material (metal), such as copper, deposited on a substrate, such as a semiconductor wafer, and embedded in fine interconnect recesses provided in an insulating film (interlevel dielectric film) formed on the substrate, thereby forming interconnects, and to a polishing apparatus that uses the polishing pad. [0003] The present invention also relates to a method for conditioning a polishing pad of a polishing apparatus, and to a polishing apparatus and a polishing method which are useful for processing a film of conductive material formed on a substrate, such as a semiconductor wafer, or removing impurities adhering to the surface of the substrate. [0004] The present invention also relates to a dresser for dressing a polishing pad of a polishing apparatus, a polishing...

AI Technical Summary

Benefits of technology

[0038] Also in electrochemical mechanical polishing, a polishing pad is generally employed which is composed of, for example, a closed-or open-cell foamed polyurethane, a polyester non-woven fabric, a PVA sponge or a conductive pad. By initially conditioning such a polishing pad for use in electrochemical mechanical polishing into the optimum conditions, electrochemical mechanical polishing of a substrate can be carried out while maintaining the intended polishing rate and its uniformity in the surface of the substrate and preventing the occurrence of dishing or erosion.

[0039] Polishing and removal of a metal film, for the most part, may preferably be carried out by electrolytic polishing which performs polishing only by an electrolytic action without using abrasive grains, thus without causing significant damage to a polishing object. This can materially reduce damage to the interconnect structure of the substrate upon polishing of the metal film. An electrolytic polishing (electrochemical mechanical polishing) process is frequently employed in combination with other polishing process, such as followed by chemical mechanical p

Problems solved by technology

Such through-holes generally have a low efficiency of passage therethrough of a polishing liquid (electrolytic liquid), and therefore a polishing product and an “old polishing liquid” are likely to remain in the through-holes.

When the polishing product remains in the through-holes and is accumulated on the surface of the processing electrode, the electrical conduction between a substrate and the processing electrode will be impeded by the polishing product, which would cause lowering of polishing characteristics of the polishing apparatus and the stabilities of the characteristics.

It is thus a problem in maintaining the polishing characteristics of the polishing apparatus how to efficiently remove the polishing product and the “old polishing liquid” remaining on the surface of the polishing pad.

Such a polishing pad, however, may contact recessed portions in a surface of a film of interconnect metal or interconnect recesses whereby the recessed portions will be polished, which would cause dishing or erosion.

A large surface roughness of a polishing pad thus lowers the flattening property of the polishing pad.

A polishing pad having a small surface roughness, on the other hand, is poor in the

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