MONITORING METHOD OF PLASMA AND MONITOR

摘要

PURPOSE:To obtain the density or rate distribution of a specific chemical species in plasma by selecting sequentially measurement positions of the plasma and separating plasma light from each measurement position. CONSTITUTION:A monitor collect plasma light 2 at measurement positions in a working device 1, and a spectral means 4 extracts all of the plasma light 2 and plasma light 2a of specific wavelength emitted by the specific chemical species in the plasma light 2 alternately. The spectral means 4 is formed by fixing the discoid filter 43 consisting of a filter part 41 passing the light of the specific wavelength and plural kinds of dimming filter parts 42 having no wavelength selectivity and the discoid mask 46 consisting of a light transmission part 44 and a light shield part 45 to the rotating shaft 48 of a motor. The phases of the filter 43 and mask 46 are so set that the detection output ratio of the plasma light 2 and plasma light 2a is a proper value. A light collecting means 3 is moved to an optional position in a window 14 through a scanning mechanism.