Patent ID: 6524871
Filing Date: 2003-02-25
Classification: G01N

Abstract:
A defect inspection method for inspecting for a defect present in an inspected surface, comprising:a light frequency changing step of converting light of a predetermined frequency band to a plurality of beams of inspection light and a beam of reference light having close frequencies different from each other, a multi focal points forming step of passing the plurality of beams of inspection light through the identical optical path and focusing them on the inspected surface to form a plurality of different focal points corresponding to the beams of the inspection light, a scanning step of scanning the beams of the inspection light the inspected surface, a superposing step of superposing the beams of reflected light of the beams of inspection light from the inspected surface and the beam of reference light on each other to cause interference between them, a confocal detecting step of detecting the intensity of the related superposed light at the confocal point, a contrast waveform generating step of generating contrast waveforms in the scanning direction at the focal positions based on the detected light intensity, a combining step for combining the contrast waveforms, and a defect detecting step for detecting a defect of the inspected surface based on the combined contrast waveform.