Patent ID: 7576852

Claim:
A semiconductor wafer inspection device comprising: an optical illumination device that directs a light spot onto an inspection point on a surface of the semiconductor wafer; a first optical sensor that, of scattered light from said inspection point, receives narrowly scattered light scattered with a scattering angle that is narrower than a prescribed angle and detects intensity of said narrowly scattered light; a second optical sensor that, of scattered light from said inspection point, receives widely scattered light scattered with a scattering angle that is wider than a prescribed angle and detects intensity of said widely scattered light; and a signal processing circuit that identifies the type of laser light scatterer present at said inspection point in response to a detection signal from said first and second optical sensors, wherein said signal processing circuit comprises: first calculation means that, if the intensity of said narrowly scattered light is within a prescribed sizing range, calculates a first PLS-based size from the intensity of said narrowly scattered, light; second calculation means that, if the intensity of said widely scattered light is within said sizing range, calculates a second PLS-based size from the intensity of said widely scattered light; and identification means that, if the intensities of said narrowly scattered light and said widely scattered light are both within said sizing range, identifies the type of said laser light scatterer in accordance with both the first PLS-based size and said second. PLS-based size.