| 摘要 |
PURPOSE:To detect that plate-like works such as semiconductor wafers are present or not or get out of place on shelves in a carrier (container) without arranging sensors around the carrier. CONSTITUTION:An ultrasonic oscillator which transmits ultrasonics forwards and an ultrasonic receiver are provided to the front end of a rotary base 31 of a transfer equipment 10 on which a fork 3 is mounted in a such a manner that it recedes or advances freely. Ultrasonics emitted from the ultrasonic oscillator are reflected by the end face of a wafer W when the wafer W is present on a shelf. Therefore, it can be detected that a wafer is presented on a shelf or not by checking ultrasonics reflected from the wafer, and at the same time it can be also detected if the wafer gets out of place on the shelf or not by checking the intensity or the time lag of the reflected ultrasonics. |
