I think, but I'm not sure.

A method of cleaning process residues from the surface of a substrate processing chamber component having holes. In the method, the component is at least partially immersed into a cleaning solution having hydrafluoric acid and nitric acid, and a non-reactive gas is passed through the holes to prevent the cleaning solution from back-flowing into the holes during the cleaning process. The method is particularly useful for cleaning sputtering residue deposits from an electrostatic chuck used in a sputtering process.
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