Patent ID: 7601538

Claim:
A method of analyzing impurities in a bulk layer of a silicon wafer, the method comprising: immersing each of sets of two evaluation silicon wafers into a washing solution to obtain evaluation data, thereby contaminating each of sets of the evaluation silicon wafers to be in a same state of contamination; dissolving a surface layer portion of one of the evaluation silicon wafers with a solution including hydrofluoric acid, and measuring a concentration of impurities included in the solution; dissolving a bulk portion of the other evaluation silicon wafer with a solution including hydrofluoric acid, and measuring a concentration of impurities included in the solution; determining a calibration curve that characterizes a relation between the concentrations of the impurities in the surface layer portions of the evaluation silicon wafers and the concentrations of the impurities in the bulk portions of the evaluation silicon wafers; dissolving a surface layer portion of a silicon wafer of a test object which is immersed in the washing solution with a solution including hydrofluoric acid, and measuring a concentration of impurities included in the solution; and determining a concentration of impurities in a bulk portion of the silicon wafer of a test object based on the calibration curve using the measured concentration of the impurities.