| 摘要 |
PURPOSE:To obtain a position detection apparatus wherein, even when the surface of a substrate is rough, its good position detection accuracy can be achieved and a mark region on the substrate can be reduced (i.e., the effective area of a wafer can be expanded). CONSTITUTION:A reflection-type index plate 20 is formed; a second illumination system, for index mark use, which is independent of that for substrate illumination use is installed; beams of illumination light are supplied independently; and images of the beams of light returned from the surface of a substrate W and from the index plate 20 are formed on faces to be detected of image- sensing elements 17, 18, and a position is detected from an image signal obtained by their composed image. |
