| 摘要 |
PURPOSE:To carry an article in a vacuum vessel with a high reliability, by irradiating the article in the vacuum vessel with radio waves, which are radiated from a radio wave radiating means provided in the outside of the vessel, through a window and detecting the change of the intensity of radio waves due to the existence of the article by a radio wave detecting means provided in the outside of the vessel to detect the position of this article. CONSTITUTION:When a wafer 4 is placed just under a sputter electrode 15, the laser beam from a laser oscillator 22 passes through a glass window 24 and is turned from its course by a mirror 25 to irradiate the wafer 4. The laser beam reflected on the surface of the wafer is reflected by the mirror 25 and is made incident to a photosensor 23 through the glass window 24. When the wafer 4 is not placed just under the sputter electrode 15, the reflected light is hardly made incident to the photosensor 23. Consequently, the output of the photosensor 23 is monitored, and the rotation of a pulley 5 is stopped in accordance with the change of this output, thereby placing the wafer 4 just under the sputter electrode 15. |
