Patent ID: 6501082
Filing Date: 2002-12-31
Classification: H01J

Abstract:
A gas treatment system for supplying a treatment gas into a vacuum vessel to carry out a predetermined treatment for a substrate to be treated, said system comprising:electron adding means for emitting electrons to said treatment gas extracted from said vacuum vessel and for causing electrons to adhere to particles in said treatment gas for generating negative ions of said particles; mass spectrometry means for determining the kind of negative ions of said particles, to which electrons adhere, by said electron adding means; density estimating means for estimating the density of said particles in said treatment gas corresponding to the determined negative ions, on the basis of the measured value of the number of said negative ions determined by said mass spectrometry means; and a control part for controlling a process condition, which influences the state of said treatment gas in said vacuum vessel, on the basis of the estimated result of the density of said particles estimated by said density estimating means.