| 摘要 |
PURPOSE:To inspect the entire surface of a substrate with the same resolving capacity, by providing a light projecting system for irradiating the surface of the substrate with second light beam and a light receiving system for detecting reflected beam to detect the positional error of the surface of the substrate to an apparatus for inspecting the foreign matter on the substrate. CONSTITUTION:An inspection apparatus scans a reticle 15 using the laser beam M incident on the reticle 15 obliquely from above and selectively receives only the scattering beam from a foreign matter returned to the incident side. In this case, in order to ensure the focus and position of the beam M, it in necessary to keep the height of the surface of the reticle 15 constant. Therefore, an automatic focus AF light projecting system 70 and an AF light receiving system 71 are provided and the luminous flux of the system 70 is condensed to the point C on the scanning line of the beam M on the reticle 15 and the direct reflected light is incident on the system 71. Then, the change of the surface of the reticle 15 at an up-and-down position is detected by a photoelectric sensor. By this method, the beam diameter on the reticle is made constant and the entire surface of the substrate can be inspected with uniform resolving power. |
