US Patent 7911601 Apparatus and method for inspecting pattern

A method and apparatus for inspecting defects includes emitting an ultraviolet light from an ultraviolet light source, illuminating a specimen with the ultraviolet light in which a polarization condition of the ultraviolet light is controlled, controlling a polarization condition of light reflected from the specimen which is illuminated by the polarization condition controlled ultraviolet light, detecting the light reflected from the specimen, processing the detected light so as to detect defects, and outputting information about the defects. The ultraviolet light source is disposed in a clean environment supplied with clean gas and separated from outside.