Abrading – Abrading process – With tool treating or forming
Reexamination Certificate
2000-03-21
2001-05-08
Banks, Derris H. (Department: 3723)
Abrading
Abrading process
With tool treating or forming
C451S443000
Reexamination Certificate
active
06227948
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to chemical-mechanical polishing of semiconductor wafers and, more particularly, to an apparatus and method for reconditioning a polishing pad using a chemical-mechanical polishing apparatus.
BACKGROUND OF THE INVENTION
Chemical-mechanical polishing (CMP) is performed in the processing of semiconductor wafers and/or chips on commercially available polishing apparatus. The standard CMP polishing apparatus has a circular polishing pad and a rotating carrier for holding the wafer. A slurry is used on the polishing pad.
Ideally, a CMP polishing apparatus delivers a globally uniform, as well as locally planarized, wafer. CMP polishing pads require reconditioning to maintain uniformity in polish rate. This is done to prevent oxide and slurry debris buildup on the polishing pad. If the film of debris is not removed, then polish rates and uniformity both degrade very quickly.
Conventional polishing pad apparatus use conditioning wheels that sweep across the polishing pad. The conditioning wheel typically holds a diamond grit conditioner. The diamond grit conditioners typically have grit values in the range of 40 to 200. The diamond grit conditioner can degrade polish pad life and cause contamination from the diamond grit and associated materials. The diamond grit conditioners are also expensive.
The present invention is directed to solving one or more of the problems discussed above in a novel and simple manner.
SUMMARY OF THE INVENTION
In accordance with the invention, there is provided a method of reconditioning a polishing pad using a polishing pad material.
Broadly, there is disclosed herein a method of reconditioning a polishing pad using a chemical-mechanical polishing apparatus, wherein the polishing pad contacts a workpiece in the presence of a slurry to perform chemical-mechanical polishing on the workpiece. The method comprises contacting the polishing pad with a reconditioning pad. The reconditioning pad is made of a polishing pad material similar to that ofthe polishing pad.
It is a feature of the invention that the polishing pad and reconditioning pad are of the same material.
In accordance with one aspect ofthe invention, the contacting step comprises rotating the polishing pad relative to the reconditioning pad.
In accordance with another aspect of the invention, the contacting step comprises sweeping the reconditioning pad across the polishing pad.
It is another feature of the invention to recondition the reconditioning pad. This is done using a second reconditioning pad of the same material.
It is a feature of the invention that the reconditioning pad is adhered to a conditioning wheel using an adhesive.
There is disclose in accordance with another embodiment of the invention an apparatus for reconditioning a polishing pad using a chemical-mechanical polishing apparatus. The apparatus includes a conditioning wheel. A reconditioning pad is affixed to the conditioning wheel. The reconditioning pad is made of a polishing pad material similar to that of the polishing pad. Means are provided for supporting the reconditioning pad in contact with the polishing pad and providing relative movement there between.
It is a feature of the invention that the reconditioning pad has an adhesive backing for adhering to the conditioning wheel.
Further features and advantages ofthe invention will be readily apparent from the specification and from the drawings.
REFERENCES:
patent: 5367839 (1994-11-01), Pearce
patent: 5655951 (1997-08-01), Meikle et al.
patent: 5738574 (1998-04-01), Tolles et al.
patent: 5779526 (1998-07-01), Gill
patent: 5785585 (1998-07-01), Manfredi et al.
patent: 5807161 (1998-09-01), Manor et al.
patent: 6004196 (1999-12-01), Doan et al.
patent: 6022266 (2000-02-01), Bullard et al.
Khoury Raymond M.
Merkling, Jr. Robert M.
Ocasio Jose M.
Ziemins Uldis A.
Banks Derris H.
International Business Machines - Corporation
Wood Phillips VanSanten Clark & Mortimer
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