| 摘要 |
PURPOSE:To surely detect a misaligned semiconductor wafer mounted on a work stage even when its misalignment deviates in any direction by a structure wherein the semiconductor wafer passes through a detection plate having a cut-out part whose size is a little bigger than the external circumference of the semiconductor wafer. CONSTITUTION:When a wafer, mounted on a work stage, without being held perfectly passes through a cut-out part on a detection plate 17, a deviating and protruding part touches the detection plate 17. When the work stage is shifted further, the detection plate 17 is pressed, and a lower fixing plate 14 is shifted toward the moving direction of the work stage while it bends an elastic piece 13. Because the bending direction of this elastic plate 13 is decided by a correction plate 24, the lower fixing plate 14 is not turned or tilted and is shifted always in parallel with an upper fixing plate 10. While the lower fixing plate 14 is shifted, a light-shielding plate 23 deviates from the light path of a photoelectric switch 23; the light from a light-emitting diode illuminates a phototransistor; an electric current starts flowing; the misalignment of the semiconductor wafer is detected. |
