| 摘要 |
The defect inspecting apparatus of this invention is provided with a light source for applying illuminating light, illuminating means for applying the illuminating light from the light source onto the surface of a substrate to be inspected, a lens system for condensing the beam of light from the surface to be inspected and creating a spatial frequency spectrum on a Fourier transform plane to the surface to be inspected or a plane conjugate therewith, a light intercepting member for setting a spectrum-free area in the spatial frequency spectrum of the light from a pattern, the light intercepting member being disposed between the light source and the substrate and being effective to intercept part of the illuminating light, a space filter disposed on the Fourier transform plane or the plane conjugate therewith for passing therethrough the light in the spectrum-free area, light receiving means for receiving the beam of light passed through the space filter and outputting a photoelectric signal, the beam of light passed through the space filter being created from a defect on the surface to be inspected, and signal processing means for inspecting the surface state of the substrate on the basis of the photoelectric signal. When the circuit pattern on the surface to be inspected is an errorless circuit pattern having no defect, a spectrum-free area is set on the Fourier transform plane of that circuit pattern by the light intercepting member. When there is a defect in the circuit pattern on the surface to be inspected, a spectral component is created in the spectrum-free area. So, the light in the spectrum-free area is directed to the light receiving means by the space filter, whereby only the defect information is extracted.
|
