Patent ID: 6337488
Filing Date: 2002-01-08
Classification: G01N

Abstract:
A defect inspection apparatus for inspecting for a defect in an inspected surface, comprising:a light source emitting a beam of light of a predetermined frequency band; a light frequency changing means for receiving as its input the beam of light emitted from the light source and outputting the related beam of light converted to a plurality of beams of inspection light and a beam of reference light beam having close frequencies different from each other; a light focusing means upon which the beams of inspection light output from the light frequency changing means are incident through an identical optical path and focusing the related beams of inspection light to the inspected surface to form a plurality of different focal points corresponding to the beams of inspection light; a scanning means for scanning the focused beams of inspection light on the inspected surface; a superposing means for superposing the beam of the reflected light of the inspection light from the inspected surface and the beam of reference light to cause interference between the beams of reflected light and the beam of reference light; a confocal defecting means upon which the superposed light of the beams of reflected light and the beam of reference light is incident and detecting the intensity of the superposed light by confocal detection; and a contrast waveform generating means for generating contrast waveforms reflecting a surface shape of the inspected surface in the scanning direction at the focal positions in response to the light intensity detected by the confocal defecting means and combining the contrast waveforms.