Patent ID: 8705840

Claim:
A defect inspection device that inspects a defect of a substrate on which a repeated pattern is formed, comprising: an illumination optical system including a light source that emits Illumination light, and an aperture stop having an aperture through which the emitted illumination light passes so that the emitted illumination light is radiated onto the substrate to thereby be reflected by the substrate; a detection optical system including an objective lens that condenses the light reflected by the substrate and thereby forms a pupil image on a pupil plane; a receiver that receives, at a position where the pupil image on the pupil plane is formed by the detection optical system, diffracted light of a plurality of orders generated due to the repeated pattern formed on the substrate; and a detector that detects a defect of the repeated pattern formed on the substrate based on a brightness of a portion of a detection region out of detection regions where the diffracted light is received by the receiver, wherein at least one of a wavelength of the illumination light, a size of the aperture of the aperture stop, and a focal length of the objective lens is settable to separate the diffracted light of the plurality of orders on the pupil plane, wherein the illumination light emitted by the light source passes through the objective lens to thereby be radiated onto the substrate, the aperture stop is arranged at a position conjugate with the pupil plane, and the aperture of the aperture stop is configured to be enabled to change the position and aperture diameter within a plane orthogonal to an optical axis of the illumination optical system.