| 摘要 |
PURPOSE:To accurately and simply detect the vacuum leakage of a container by providing a window for passing a light to a vacuum container used for dry etching and a photodetector faced with the window and detecting the plasma light of N2 or O2 produced when its airtightness becomes improper. CONSTITUTION:Opposite electrode 2 to become one electrode for generating a plasma is arranged in a vacuum container 1 forming a plasma etching device in such a manner that the potential of the electrode 2 is set to the same potential of the container 1. A water-cooled electrode 3 is arranged via a dielectric unit 4 for shielding from the container 1 oppositely to the electrode 2, a wafer 7 for a semiconductor device is placed as a member to be etched thereon, is energized by a high frequency power source, and the internal gas is converted to the plasma. In this configuration, a window 8 is opened at one side wall of the container 1, and a photodetector 10, e.g., a photodiode or the like is mounted via a filter 9 passing the characteristic wavelength of N2, O2 thereat. In this manner, the plasma light of N2, O2 always produced when the airtightness of the container 1 becomes improper is selectively detected, thereby effectively detecting the leakage. |
