| 摘要 |
<p>PURPOSE:To detect the arrangement of semiconductor wafers in a wafer cassette at high speed by a method wherein the title mechanism is constituted of a counter part; which counts the pulses of a pulse oscillator for making a pulse motor, which moves continuously a wafer detecting means, drive, sets a timing for detecting the output of the wafer detecting means and sends an end signal to a CPU when the count of the pulses reaches a prescribed number; and a shift register for storing in order the output of the wafer detecting means. CONSTITUTION:A START signal is sent by a command from a CPU 7 and thereafter, a starting is applied to a pulse oscillator 8 and a pulse motor 6 is actuated by a pulse driver 9. A counter 10a counts the pulses of the oscillator 8 and in case the counter 10a counts up, a counter 10b adds +1 to the count of the pulse. Simultaneously, a shift register shifts present data on a sensor amplifier 4 and stores therein. The counter 10a is cleared. Thereby, the detection of a semiconductor wafer 2 in a cassette first groove 1a in a wafer cassette 1 ends. The CPU 7 reads the data in the register 11 and the detection of the arrangement of the wafer 2 ends.</p> |
