Abrading – Accessory – Cooling
Reexamination Certificate
1999-05-10
2001-06-26
Rachuba, M. (Department: 3724)
Abrading
Accessory
Cooling
C450S053000, C450S056000
Reexamination Certificate
active
06251001
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to substrate polishing techniques, including chemical mechanical polishing (CMP).
Chemical mechanical polishing is a process by which a substrate surface is smoothed (planarized) to a uniform level by a polishing pad and an abrasive slurry. A substrate to be polished is usually mounted on a rotatable carrier head and pressed against a moving polishing pad. The polishing pad typically consists of an abrasive sheet. An abrasive chemical solution (slurry) may be introduced onto the polishing pad to assist in the polishing process. Typically, a rinse arm supplies de-ionized water or other rinse fluid to the polishing pad to remove coagulated slurry and other material from the polishing pad surface.
SUMMARY OF THE INVENTION
In one aspect, the invention features systems and methods for polishing a substrate with reduced contamination. A substrate polishing system comprises: a substrate polishing apparatus including a substrate carrier, a polishing surface, and a slurry dispenser; and a humidifier configured to direct moist air to one or more surfaces in proximity to the polishing surface and exposed to airborne slurry particles generated during polishing. A method of polishing a substrate with a substrate polishing system comprises: supporting a substrate above a polishing surface; dispensing slurry onto the polishing surface; polishing the substrate against the polishing surface; and directing moist air to one or more surfaces of the substrate polishing system in proximity to the polishing surface and exposed to airborne slurry particles generated during polishing.
Embodiments may include one or more of the following features.
The humidifier may be configured to direct moist air in the vicinity of the substrate carrier. In one embodiment, the humidifier comprises a liquid atomizer. In another embodiment, the humidifier comprises a nozzle. In accordance with this embodiment, the humidifier is configured to receive a liquid and a gas, to mix received liquid and gas, and direct the mixed liquid and gas through the nozzle to generate a fine mist in the vicinity of the one or more exposed surfaces.
In operation, the humidifier may be configured to maintain the atmosphere in the vicinity of the one or more exposed surfaces at a relative humidity level of about 80% or greater. In one mode of operation, the humidifier may be configured to maintain a layer of liquid on the one or more exposed surfaces.
A humidistat may be coupled to the humidifier to control the humidity in the vicinity of the exposed surfaces.
Among the advantages of the invention are the following. By maintaining the atmosphere in the vicinity of the exposed surfaces at an elevated relative humidity level, airborne slurry particles adhering to the exposed surfaces remain in suspension and, therefore, may be easily cleaned, e.g., during a high pressure rinse cycle. This feature reduces the likelihood that slurry particles will accumulate on exposed surfaces of the polishing apparatus and flake off while a substrate is being polished, reducing the likelihood of substrate defects caused by such slurry contamination.
REFERENCES:
patent: 5195922 (1993-03-01), Genco
patent: 5401212 (1995-03-01), Marvell et al.
patent: 5431599 (1995-07-01), Genco
patent: 5595522 (1997-01-01), Simpson et al.
patent: 5779520 (1998-07-01), Hayakawa
patent: 5797789 (1998-08-01), tanaka et al.
patent: 6053801 (2000-04-01), Pinson et al.
Bennett Doyle E.
Bonner Benjamin A.
Brown Brian J.
Flores Paul
Osterheld Thomas H.
Applied Materials Inc.
Fish & Richardson
Rachuba M.
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