US 7,507,670 B2
Silicon electrode assembly surface decontamination by acidic solution
Hong Shih, Walnut, Calif. (US); Tuochuan Huang, Saratoga, Calif. (US); and Chunhong Zhou, Fremont, Calif. (US)
Assigned to Lam Research Corporation, Fremont, Calif. (US)
Filed on Dec. 23, 2004, as Appl. No. 11/19,726.
Prior Publication US 2006/0141802 A1, Jun. 29, 2006
Int. Cl. H01L 21/302 (2006.01)
U.S. Cl. 438—704  [257/347; 438/459; 137/3] 21 Claims
 
1. A method of cleaning a used electrode assembly for generating plasma in a plasma etch chamber comprising a plasma-exposed silicon surface, the method comprising contacting the silicon surface with an acidic cleaning solution comprising:
0.25 to 1% by volume hydrofluoric acid;
10 to 40% by volume nitric acid;
10 to 20% by volume acetic acid; and
balance deionized water; and
wherein contaminants are removed from the silicon surface; and
further wherein the silicon surface is not discolored as the acetic acid is present in an amount effective to control oxidation by the nitric acid.