| 摘要 |
In an apparatus for detecting foreign matter on the surface of a substrate (O) carrying a circuit pattern (C), the surface to be inspected is scanned by a polarized laser beam (L), and a detecting optical system is provided for detecting the intensities (I1,I2) of two polarized components with different angles of polarization of the light (R) which is scattered and/or reflected at the surface of the substrate. The existence of foreign matter onthe surface of the substrate is discriminated on the basis of the result of a comparison between the intensities of the two polarized components. According to invention, a beam splitter (S) is used for extracting the two polarized components from a single beam (R0)* of reflected scattered light. Since both polarized components are extracted from light which has been reflected or scattered into the same direction, the comparison result is not affected by differences in the intensity of the light (R) scattered or reflected into different directions. |
