摘要 |
An apparatus for detecting the presence of a wafer cassette, or pod, resting on an arrangement of pins allows cassette detection without interfering with insertion of a robotic paddle arm beneath the cassette to remove it for transport. A cassette resides on an arrangement of beveled pins which mate with corresponding receptacles on the underside. Pins supporting the cassette have a spring biased, hollow outer cylinder coaxially mounted around a center post. A cassette placed on the pins displaces the outer cylinder downward a sufficient distance to trigger a sensor. Upon removal of the cassette, the outer cylinder is displaced upwards, resetting the sensor.
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