METHOD AND APPARATUS FOR OPTICAL DETECTION OF EFFLUENT COMPOSITION

摘要

A method and apparatus for determining the composition of an effluent stream from a vacuum processing chamber. A cell placed in the effluent stream from the vacuum processing chamber creates a glow discharge from the constituents in the effluent stream. An optical detector measures a particular wavelength corresponding to the presence of a particular species. In one embodiment the output from the optical detector is used to determine the endpoint of a chamber cleaning process.