Slurry distributor for chemical mechanical polishing apparatus and method of using the same

Abstract

A polishing apparatus (100) is provided for polishing a substrate (102) that has slurry distributor (125) which improves planarization uniformity. Generally, apparatus (100) includes: (i) platen (106) with polishing surface (110); (ii) head (116) adapted to hold substrate (102) against polishing surface; (iii) mechanism to rotate platen (106) during polishing; (iv) dispenser (124) having nozzles (126, 128) to dispense slurry on the surface (110); and (v) distributor (125) between the nozzles (126, 128) and head (116). In one embodiment, apparatus (100) further includes a wiper (180) between head (116) and distributor (125) to remove used slurry and polishing byproducts from surface (110), thereby reducing agglomerations or deposits that can damage substrate (102) and improving yield. Optionally, apparatus (100) further includes dispenser (186) for dispensing a fluid before and / or after wiper (180) to substantially eliminate buildup of deposits. Method for polishing and substrate polished according to method.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of and claims the benefit of priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 10 / 234,780 filed 3 Sep. 2002 and entitled Slurry Distributor For Chemical Mechanical Polishing Apparatus And Method Of Using The Same, which application claimed priority from U.S. Provisional Patent Application Ser. No. 60 / 323,117, filed Sep. 10, 2001, each of which applications are incorporated herein by reference.FIELD OF THE INVENTION [0002] This invention pertains generally to systems, devices, and methods for polishing and planarizing substrates, and more particularly to an apparatus and method for distributing slurry on a polishing surface of a chemical mechanical polishing (CMP) apparatus. BACKGROUND OF THE INVENTION [0003] As feature size decreases, density increases, and the size of semiconductor wafers or substrates increase, Chemical Mechanical Planarization (CMP) process requirements become more st...

AI Technical Summary

Benefits of technology

[0015] In another embodiment, the distributor further includes one or more guide or spacers on the lower surface thereof, the spacers adapted to contact the polishing surface during a polishing operation and to guide or position the distributor relative to the polishing surface. Preferably, the spacers include an adjustment mechanism to adjust a gap between the lower surface of the distributor and the polishing surface, thereby enabling a rate of removal of material from the substrate to be varied.

[0028] (iv) improved yields due to reduction or eliminating of buildup or deposits of solid polishing byproducts that can damage the substrate.

Problems solved by technology

Substrate to substrate process uniformity as well as intra-substrate planarization uniformity are important issues from the standpoint of producing semiconductor products at a low cost.

As the size of dies increases a flaw in one small area increasing results in rejection of a relatively large circuit so that even small flaws have relatively large economic consequences in the semiconductor industry.

One problem with slurry distribution in a conventional CMP apparatus a non-uniform distribution of slurry on a polishing surface. FIG. 1 is a top plan view of a platen and a slurry dispenser in a conventional CMP apparatus illustrating a non-uniform distribution of slurry on a polishing surface.

While an improvement over conventional slurry dispensers, this approach is not wholly satisfactory for a number of reasons.

One problem with the approach taught in GUTHRIE is that the constant contact between the flexible member and the polishing surface during polishing operations causes rapid wear of the flexible member.

This in turn leads to the need to frequently replace the flexible member.

In addition to the cost of replacement parts, this results in excessive down time or loss of availability or the apparatus for processing due to the time needed to replace the flexible member and the time need to re-characterize the polishing process or apparatus.

Moreover, prior to replacement, as the flexible member wears the amount and distribution of slurry across the polishing surface can vary introducing a new source of non-uniformity.

This is particularly a problem with polishing surfaces comprising a pattern of features, such as indentations in a porous polishing surface or concentric grooves, for aiding in slurry distribution.

These features cause the flexible member to wear unevenly across the surface in contact with the polishing surface, resulting in a non-uniform distribution of slurry across the polishing surface.

Another problem with conventional CMP apparatuses and methods, related to the problem with non-uniform distribution described above, is the inefficient use and wastage of slurry.

Because of strict requirements concerning the purity of the slurry and in particular the size of the abrasive particles suspended therein, slurry tends to be expensive.

Moreover, because materials used in fabricating semiconductors are often hazardous to people and to the environment, used slurry, which can contain significant amounts of material removed from the substrates, must be disposed of as hazardous waste.

Thus, a significant factor in the cost of operating conventional CMP apparatuses is the cost of supplying and disposing of the slurry.

Yet another problem with conventional CMP apparatuses and methods is the buildup of solid polishing byproducts on the polishing surface that can damage or destroy a substrate being polished.

This particularly a problem for CMP apparatuses including polishing surfaces with numerous small, shallow grooves for the distribution of slurry, or porous polishing pads or coverings.

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