Patent ID: 9488596
Filing Date: 2016-11-08
CPC Classification: G01N

Claim Text:
1. A defect inspection device, comprising: an illumination optical unit which illuminates a sample with a laser beam from a oblique direction; a detection optical unit which detects light diffracted from the sample illuminated with the laser beam by the illumination optical unit; and a signal processing unit which detects a defect on the sample by processing an electrical signal generated by detecting the light diffracted from the sample with the detection optical unit, wherein, the detection optical unit installs plural detectors including a photon counting type detector having plural pixels, the plural detectors including a front detector which detects forward-scattered light which scattered in forward direction to a illumination direction of the laser beam to the sample by the illumination optical unit and a backward detector which detects back-scattered light which scattered in backward direction to a illumination direction of the laser beam to the sample by the illumination optical unit, and a pixel number of the front detector is larger than that of the backward detector so that a photon detection efficiency of the front detector is higher than a photon detection efficiency of the backward detector.