| 摘要 |
<p>PURPOSE:To provide a detector which is easily maintained and able to detect if wafers protrude from a cassette housed in an airtight container. CONSTITUTION:A transparent, view port 32 and a detecting means 35 equipped with a light emitting device and a photodetective device are provided in a bell jar 26 of 8 load lock chamber 23. A housing a prism 31 which reflects detecting light emitted from the light emitting device towards the photodetective device is provided to the mounting pad 29. If a wafer W0 protrudes from the housing cassette 30, detecting light is blocked by it, whereby it is detected that the wafer W0 protrudes.</p> |
