Processing method and processing apparatus for ingot

Abstract

An ingot is processed by applying exciting light, and detecting fluorescence occurring from an upper surface of the ingot. A distribution of the number of photons of the fluorescence on the upper surface of the ingot is stored as two-dimensional data in association with XY coordinate positions, and a Z-coordinate position at which the two-dimensional data is obtained is also stored. A laser beam forms a peeling layer by irradiating the ingot while positioning the condensing point of the laser beam at a depth corresponding to the thickness of a wafer from the upper surface of the ingot. A wafer is separated from the ingot with the peeling layer as a starting point, and three-dimensional data is generated representing the distribution of the number of photons of the fluorescence in the whole of the ingot on the basis of two-dimensional data at each Z-coordinate position of the ingot.