| 摘要 |
<p>PURPOSE: To provide a wafer detection device which can detect all kinds of wafers having different reflectivity though the device can be manufactured at a low cost and fitted and adjusted easily and, at the same time, which is surely prevented from making false detection due to dropping wafers. CONSTITUTION: A reflection beam sensor 60 whose sensitivity is adjusted to a low-reflectivity wafer with a substantially long detecting distance L is used and a detecting beam transmitting window 62 is provided through the bottom plate 52A of a chamber 52 at the position corresponding to the sensor 60 so that a detection beam LB reaching the bottom 52B of the chamber 52 cannot be transmitted through the window 62 when no wafer W exists at a detecting position. At the same time, a projection 64 is provided near the window 62 as a wafer supporting section to support a wafer W dropping onto the bottom 52B of the chamber 52 in an inclined state so that a reflected beam LB1 from the wafer W can be directed away from the sensor 60.</p> |
