| 摘要 |
At the time of pulling out a wafer pallet (32) in a magazine to a pickup position by means of a pulling out mechanism, an outer expand ring (45) on the wafer pallet (32) passes through a detection area (optical axis) of optical sensors (46, 47) (projection element and light receiving element). At that time, the outer diameter of the outer expand ring (45) is measured on the basis of a shift quantity of the wafer pallet (32) from a position where output of the optical sensor (47) on the light receiving side is switched to turn off to a position where the output is switched to turn on again, and the inner diameter of the inner expand ring (45) is calculated on the basis of the outer diameter measurement value of the outer expand ring (45), and the total width of the inner and outer expand rings (44, 45). |
