| 摘要 |
<p>PURPOSE:To facilitate the identification of a wafer for a product and a dummy wafer during a wafer process by casting luminous flux into a rotating crystal to be detected, receiving the reflected light from the crystal, and performing photoelectric conversion for the reflected light. CONSTITUTION:The light, which is outputted from a light emitting element 1 is condensed with a lens 2 and cast on an arbitrary position on a rotating wafer 4 through a slit 3. The reflected light from the wafer 4 is received with a light receiving lens 6, which is arranged at the rear of a slit 5 on the opposite side provided at a position, that is slightly separated from the slit on the incident side. Photoelectric conversion is performed with a photodetector 7. The converted voltage is inputted into a detecting circuit 8, and the waveform of the voltage of the reflected light is observed. The number of the crests of the waveform during one rotation of the wafer is counted, and the crystal orientation is detected. The crest of the voltage waveform is formed at every time the photodetector passes the image of the light by the rotation of the crystal.</p> |
