摘要 |
PURPOSE: A wafer load check sensor is provided to prevent breakage of a wafer by easily and exactly checking the loading and unloading state. CONSTITUTION: A sensor(210) is located on a wafer transfer chuck(200). At this time, the sensor has a desired offset angle from the perpendicular direction of a wafer. A reflection mirror(110) on a quartz lifter(100) is located to align the sensor. That is, the reflection mirror also has the offset angle same to the sensor. Preferably, the offset angle is about 9 degree.
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