| 摘要 |
<p>PURPOSE:To stop a manufacturing apparatus at a stage where a wafer is cracked in the apparatus so that further to prevent dust cracking and dust from cracks are avoided in the next stage. CONSTITUTION:A change in the input level of a photodetector 2 is discriminated by using a discrimination circuit 3. When the change has reached a certain level, it is output to a counter circuit 4 as a crack detection level. A set value at the counter circuit 4 is compared with that at a setting device 6 by using a control circuit 5. When they coincide, a crack detection signal is output.</p> |
