Method of evaluating quality of silicon wafer and method of reclaiming the water

摘要

A method of evaluating the quality of a silicon wafer is characterized by analyzing a silicon wafer by an infrared absorption spectrum, and then evaluating the quality of the silicon crystal based on an absorbance ratio represented by the following formula (1):; $PTEXTPDAT\{(Absorbance\; \&agr;1\; at\; an\; arbitrary\; wavenumber\; between\; 1055\; and\; 1080\; cm/PDATHILSPPDAT\−1/PDAT/SP/HILPDAT)\−(Absorbance\; \&agr;BL\; of\; base\; line)\}/\{(Absorbance\; \&agr;2\; at\; an\; arbitrary\; wavenumber\; between\; 1100\; and\; 1120\; cm/PDATHILSPPDAT\−1/PDAT/SP/HILPDAT)\−(Absorbance\; \&agr;BL\; of\; base\; line)\}\ \ (1)/PDAT/PTEXT$ ;wherein absorbances &agr;1 and &agr;2 represent absorbances of the measured silicon wafer, and base line absorbance &agr;BL represents the absorbance of a base line of the measured silicon wafer, which is drawn from 1030 to 1170 cm^−1. By using the quality evaluating method of the present invention, internal crystal defects of silicon can be precisely detected in a non-destructive manner. The method of the present invention thus has the advantages of improving productivity, decreasing reclaiming cost, etc.