| 摘要 |
PURPOSE:To enable an increase in separate detection rate of a foreign matter for a circuit pattern, by arranging an optical axis of a focusing section of a light receiving means to be positioned on the incidence side with respect to a normal within an incidence surface of a substrate. CONSTITUTION:A polygon mirror 2 and a projection section 4 compose a part of a projection means. A mirror 2 is rotated to scan over a substrate 5 from a point B1 to point B2 while the substrate 5 is moved in the direction of the arrow S1 or S2 to scan the whole of substrate 5. A focusing section 6 is provided on the incidence side with respect to a normal on an incidence surface of the substrate 5 and focus scattered luminous fluxes from a foreign matter on the substrate 5 and then introduced to a light receiving surface 9 with a lens 8. The focusing section 6, the mirror 7 and the lens 8 composed a part of a light receiving means. On the other hand, with the rotation of the mirror 2, a luminous flux emitted at the reflection point PG is scattered by the foreign matter on the substrate 5 to be focused 6. This can achieve a higher separate detection rate of a foreign matter for a circuit pattern. |
