Method of wafer inspection system

Abstract

A method includes performing a first wafer inspection process using an illumination source in a wafer inspection tool; replacing the illumination source with a new illumination source; generating a radiation beam from the new illumination source; placing an assisting tool along a propagation path of the radiation beam, wherein the assisting tool has a hole, and wherein the radiation beam creates a light spot around the hole of the assisting tool; determining whether the propagation path of the radiation beam is along a predetermined propagation path based on a position of the hole and a position of the light spot; and performing a second wafer inspection process using the new illumination source in response to the propagation path of the radiation beam being determined as along the predetermined propagation path.

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