Pretreatment method for impurity analysis of semiconductor silicon crystal, and impurity analysis method of semiconductor silicon crystal

摘要

PROBLEM TO BE SOLVED: To provide a preprocessing method which allows a larger amount of sample to be completely dissolved in a shorter time by vapor phase decomposition, in preprocessing for analyzing impurities of a semiconductor silicon crystal.SOLUTION: A preprocessing method for analyzing impurities of a semiconductor silicon crystal is a method for conducting vapor phase decomposition of the whole of a sample picked up from the semiconductor silicon crystal, by putting the sample and a mixed acid of hydrofluoric acid and nitric acid in a closed vessel and then heating the mixed acid to generate mixed acid vapor in preprocessing for analyzing impurities of the semiconductor silicon crystal. In this method, a closed vessel with a pressure adjustment valve is used as the closed vessel, and vapor phase decomposition is conducted while volatile decomposition products generated in the closed vessel and the mixed acid vapor are leaked through the pressure adjustment valve so that a pressure in the closed vessel is 0.20 MPa or higher and 0.40 MPa or lower in terms of absolute pressure.SELECTED DRAWING: Figure 1