Patent ID: 6624897
Filing Date: 2003-09-23
Classification: G01N,H01L

Abstract:
An apparatus for the detection of material layer boundaries in a semiconductor wafer, said apparatus comprising:an electromagnetic radiation source for emitting an electromagnetic radiation beam directed at a mounting surface for a wafer, said electromagnetic radiation beam having a property that it will be reflected by a material layer of a wafer when the wafer is mounted on said mounting surface; an electromagnetic radiation detector positioned to receive a reflected electromagnetic radiation beam and for measuring the intensity of the electromagnetic radiation beam after the electromagnetic radiation beam has been reflected from a material layer of a wafer; a system for moving said radiation source and detector relative to said wafer mounting surface such that said electromagnetic radiation beam and associated reflected beam scan an area of a wafer mounted on said mounting surface; and a device coupled to said detector for determining a change in intensity of said reflected beam when said radiation beam scans over a boundary region of a material layer of a wafer mounted on said mounting surface.