Method for removing metal surface contaminants from silicon
AssigneeHemlock Semiconductor Corporation
InventorsLydia Lee-York Hwang, Arthur Francis Porsche
Life of this patent
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Abstract
A method for removing metal surface contaminants from silicon metalloid. The method comprises sequentially contacting the silicon with gaseous hydrogen fluoride and then with an aqueous solution comprising at least one-half weight percent hydrogen peroxide. The method is especially useful as a means for recovering metal surface contaminants on semiconductor grade silicon for analysis of surface contamination of the silicon by such metals. The method is useful for recovering copper from the surface of semiconductor grade silicon in an aqueous solution which can be analyzed directly to determine the amount of copper contamination of the surface of the silicon.
Claims20
A method for removing metal surface contaminants from a silicon metalloid, the method comprising:
- (A) in a first step contacting silicon metalloid having a metal surface contaminant with vapor phase hydrogen fluoride and
- (B) in a second step contacting the silicon metalloid having the metal surface contaminant with an aqueous solution consisting essentially of at least one-half weight percent hydrogen peroxide.
A method for analyzing semiconductor grade silicon for metal surface contaminants, the method comprising:
- (A) in a first step contacting semiconductor grade silicon metalloid having a metal surface contaminant with vapor phase hydrogen fluoride,
- (B) in a second step contacting the semiconductor grade silicon metalloid with an aqueous solution consisting essentially of at least one-half weight percent hydrogen peroxide thereby forming an aqueous phase containing the metal surface contaminant, and
- (C) analyzing the aqueous phase to determine metal concentration.
A method for analyzing semiconductor grade silicon for surface contamination by copper, the method comprising:
- (A) in a first step contacting semiconductor grade silicon metalloid having copper as a surface contaminant with vapor phase hydrogen fluoride,
- (B) in a second step contacting the semiconductor grade silicon metalloid with about 10 ml to 20 ml per 100 g of silicon of an aqueous solution consisting essentially of about 1.5 to five weight percent hydrogen peroxide thereby forming an aqueous phase containing the copper, and
- (C) analyzing the aqueous phase to determine copper concentration by graphite furnace atomic absorption.
Dependencies are inferred from the claim text.