| 摘要 |
<p>PURPOSE:To obtain the good position detection accuracy of the title apparatus even when the surface of a wafer is rough, to reduce a mark region on the wafer and to increase the effective area of the wafer. CONSTITUTION:A wafer mark on a wafer W is irradiated with irradiation light from a light source 1; an index mark on a reflection-type index plate 20 is irradiated with irradiation light guided from the light source 1 independently of the irradiation light for the wafer W. The image of the wafer mark and the image of the index park are formed parallelly on image formation surfaces on image sensing elements 17, 18. The positional relationship between both is detected.</p> |
