Patent ID: 7755751
Filing Date: 2010-07-13
Classification: G01N

Abstract:
1. An optical inspection method for detecting a contaminant particle/defect existing on a surface or in an internal part near a surface of a sample, using a sample stage adapted for first translation movement in primary scanning and second translation movement along a direction substantially orthogonal to the first translation movement in secondary scanning or a sample stage adapted for rotational movement in primary scanning and translation movement in secondary scanning, a pulse laser source for oscillating pulses temporally repetitively, an illumination unit for radiating a pulse light from a light source on the surface of the sample, and a scattered/diffracted/reflected light detection unit for detecting the radiated light scattered/diffracted/reflected on the sample, wherein the illumination unit includes a unit for splitting a single light flux emitted from the pulse laser source into a plurality of light fluxes, a time delay optics for giving a different delay time for each of the plurality of the split light fluxes, a unit for forming a plurality of illumination spots by radiating the plurality of the light fluxes having different delay time at a plurality of discrete positions in predetermined spaced relationship to each other on the surface of the sample, and a light emission timing signal generating unit for indicating the light emission timing of each of the plurality of the light fluxes having different delay time inside or outside the illumination unit, and wherein the scattered/diffracted/reflected light detection unit includes a photodetector substantially simultaneously entered by the scattered/diffracted/reflected light generated from the plurality of the illumination spots on the surface of the sample, and the scattered/diffracted/reflected light signal due to the scattered/diffracted/reflected light from each of the plurality of the illumination spots is isolated and detected by controlling the output signal of the photodetector based on the light emission timing signal.