Patent ID: 7686973
Filing Date: 2010-03-30
Classification: H01L

Abstract:
1. A method for analyzing impurities of a silicon wafer, the method comprising the steps of: applying a carrier gas through a mixed solution of hydrofluoric acid and nitric acid or of hydrofluoric acid, nitric acid and sulfuric acid to obtain an etching gas; introducing the etching gas obtained by bubbling and containing vaporized hydrofluoric acid and nitric acid into a vessel equipped with an inlet and an outlet; cooling said vessel to a specific temperature, wherein the etching gas is condensed on the surface of a silicon wafer that is held inside said vessel and that has been cooled, thereby etching said surface; recovering any decomposition residue by maintaining a droplet of mixed solution of hydrofluoric acid and aqueous hydrogen peroxide between a nozzle and the wafer and moving the nozzle to apply the solution on the wafer, then applying suction to the nozzle and moving the nozzle for recovery by suction of the solution with the residue; and analyzing said residue.