| 摘要 |
PURPOSE:To prevent reaction products and reactive gas ions from reaching a light measuring window and avoid degradation of measurement accuracy by a method wherein an intermediate cylinder is provided between a vacuum treatment chamber and the light measuring window and a magnetic field is applied to the cylinder and its environs to deflect the reaction products and the reactive gas ions. CONSTITUTION:In order to observe the light emitting state of a plasma 8, a light measuring window 4 is provided on a vacuum treatment chamber 1 with an intermediate cylinder 9 between and a photodetector 5 is provided. A coil guide 10 and a coil 11 are provided on the intermediate cylinder 9 and the coil 11 is exited by an exciting source 12. A magnetic field induced by the excitation deflects reaction products and reactive gas ions to prevent them from adhering to the light measuring window 4. With this constitution, the intensity of the transmitted light becomes constant and the detection accuracy of a terminating point detector can be improved.
|
