Diffraction pattern suppression method for use in association with the optical inspection of semiconductor wafers, whereby a matched suppression pattern is temporarily created in an optical fashion using a light sensitive layer

摘要

Method has the following steps: provision of a semiconductor wafer (5) to be examined, provision of an optical inspection unit (14), provision of an absorbing plate (20) with an optically transparent substrate (22) and a light-sensitive layer (26) between the wafer and a detector (16), illumination of the front side (10) of the wafer, and formation of a pattern of absorbing elements (24) using the light sensitive layer, illumination of the front side of the wafer for a second period and detection of the scattered light for the second time period. Independent claims are also included for the following:- (A) a further method for suppressing diffraction patterns during the optical inspection of semiconductor wafers and; (B) an optical inspection unit for inspecting a semiconductor wafer.