Patent ID: 7768635
Filing Date: 2010-08-03
Classification: G01N,H01L

Abstract:
1. A defect inspection apparatus comprising: a movable stage for mounting a substrate having circuit patterns as an object of inspection; an irradiation optical system that guides a light beam emitted from a laser light source to a first or a second optical path, focuses the light beam that has been guided to the first or second optical path into a slit-shaped light beam at the surface of the substrate, the first and the second optical paths are the same in elevation angle and different in azimuth angle to the substrate; a detection optical system which includes an image sensor for receiving reflected/scattered light from the substrate by the irradiation of the slit-shaped light beam and converting the received light into a signal; and an image processor which processes the signal for extracting a signal indicative of defect; wherein each of the first optical path and the second optical path of the irradiation optical system includes a cylindrical lens and a coherency reduction optical system, the coherency reduction optical system being adapted to receive the light beam having optical coherency and to emit a plurality of slit-shaped light sub-beams which are spatially reduced in coherency in a light-converging direction of the cylindrical lens, the cylindrical lens being adapted to focus the plurality of slit-shaped light sub-beams into the slit-shaped light beam irradiated to the surface of the substrate, and wherein the image processor calculates features of the extracted signal indicative of defect based on a first inspection signal obtained by receiving light from the substrate irradiated by the slit-shaped light beam from the first optical path and a second inspection signal obtained by receiving light from the substrate irradiated by the slit-shaped light beam from the second optical path, and classifies kind of defect by using information of the calculated features.