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Particulate contamination removal from wafers using plasmas and mechanical agitation

United States Patent

5,849,135
December 15, 1998
View the Complete Patent at the US Patent & Trademark Office
Los Alamos National Laboratory - Visit the Technology Transfer Division Website
Particulate contamination removal from wafers using plasmas and mechanical agitation. The present invention includes the use of plasmas with mechanical agitation for removing particulate matter from the surface of a wafer. The apparatus hereof comprises a mechanical activator, at least one conducting contact pin for transferring the vibration from the activator to the wafer, clamp fingers that maintain the wafer's position, and means for generating a plasma in the vicinity of the surface of the wafer, all parts of the cleaning apparatus except the mechanical activator and part of the contact pin being contained inside the processing chamber. By exposing a wafer to a plasma and providing motion thereto in a direction perpendicular to its surface, the bonding between the particulate matter and the surface may be overcome. Once free of the wafer surface, the particulates become charged by electrons from the plasma and are drawn into the plasma by attractive forces which keep them from redepositing. The introduction of a flowing gas through the plasma sweeps the particulates away from the wafer and out of the plasma. The entire surface is cleaned during one cleaning step. The use of an rf plasma to accomplish the particulate removal was found to remove more than 90% of the particulates.
Selwyn; Gary S. (Los Alamos, NM)
The Regents of the University of California (Los Alamos, NM)
08/ 614,110
March 12, 1996
The invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy to The Regents of The University of California. The government has certain rights in this invention.