Patent ID: 8274652

Claim:
A defect inspection method, comprising: emitting periodic pulsed illuminating light from a light source; polarizing the periodic pulsed illuminating light into a plurality of polarization states; splitting the periodic pulsed illuminating light into beams, wherein a beam differs from another beam in polarization state and illumination orientation; changing illumination orientations of beams, while keeping their polarization states unchanged; illuminating the beams that differ from one another, both before and after changing their illumination orientation, onto a predetermined area of an inspection subject substrate, such that the beams generate scattered light components; detecting images of the predetermined area that differ temporally from one another, and some of which differ in polarization state and/or illumination orientation, wherein the image detection is based on scattered light components guided to a detector in a predetermined range of an azimuthal angle and in a predetermined range of an elevation angle, and wherein each image is affected by the polarization state and illumination orientation of the beam that generated the scattered light components; extracting values of features from the images of the predetermined area; and determining a defect by finding a value that deviates from a relationship between values of the features of the images.