| 摘要 |
PROBLEM TO BE SOLVED: To use the read-in pulse of a rotary encoder as the amount of the gap between the upper surface of a fork at the time of advance of the fork and the bottoms of wafers and to make it possible to veryfy and monitor the positions of the wafers by a method wherein a pulse signal from the rotary encoder, which reads the amount of operation of the fork, is read in a carrying device and a wafer suction signal is catched by a vacuum sensor. SOLUTION: The amount of ascension of a fork 1 subsequent to an insertion of the fork 1 between semiconductor wafers 2 is read from the pulse of a rotary encoder 12. A pressure change in the contact points of the upper surface of the fork 1 with the wafers 2 is taken in a transfer device as the output of a vacuum sensor 11 and the relative position of the upper surface of the fork 1 of the semiconductor device at the time of the insertion of the fork 1 between the wafers 2 to the rears of the wafers 2 is detected. The operation of this detection is conducted by all throttles in wafer support boats or a wafer carrier, whereby a change in the pitch between the wafer support boats or between the wafer support parts of the wafer carrier, a suddenly generated change in the positions of the wafer support parts or a mechanical change in the position of the device can be detected. |
