| 摘要 |
<p>PURPOSE: To confirm the presence of the placing wafers on each carrying arm in a single-wafer type semiconductor manufacture treating a plurality of substrates in parallel. CONSTITUTION: A plurality of carrying arms 2a, 2b can be moved independently, the carrying arms are driven so that wafers 8 receives and placed on the carrying arms interrupt the optical axes of transmission type photodetectors 5, 6, the presence of substrates is detected by the discrimination of the carrying arms detecting the substrates and signals from the photodetectors, and the presence of the substrates to a plurality of the carrying arms is detected by one transmission type photodetector.</p> |
