Patent ID: 8921798

Claim:
A defect inspection apparatus comprising: a pulsed laser light source for emitting ultraviolet light; illumination optics for irradiating with the ultraviolet light a surface of a sample; first detection optics for forming a first enlarged image of the surface of the sample; an image sensor for detecting light back-scattered on the surface of the sample to acquire the first enlarged image of the sample; and an image processing unit for processing the first enlarged image of the sample; wherein: the pulsed laser light source comprises: a mode-locked laser as an oscillator; a band pass filter for narrowing a spectral bandwidth of light from the mode-locked laser; an amplifier disposed posterior to the band pass filter; and a wavelength converter configured to convert light amplified by the amplifier into the ultraviolet light; the spectral bandwidth of the light narrowed down by the band pass filter falls within a light-spectral bandwidth range permissible according to a particular chromatic aberration level of the illumination optics and a particular chromatic aberration level of the first detection optics; and the spectral bandwidth of the ultraviolet light output from the pulsed laser light source is between 10 pm and 20 pm.