SURFACE TESTER AND SURFACE TESTING METHOD

摘要

A surface tester comprises an illumination part which illuminates the bevel edge part of a wafer to be tested from a direction deviated from the direction of the normal line of the edge part by a predetermined angle, an imaging optical system which forms an image of diffracted light from the edge part, an imaging part which captures an image obtained by the imaging optical system, and a detection means which detects the presence or absence of a defect depending on whether a linear image appears in an image corresponding to the edge part obtained by the imaging part.