Method and apparatus for detecting plasma unconfinement

摘要

A method for detecting plasma unconfinement in a reaction chamber during a bevel edge cleaning operation is provided. The method initiates with selecting a wavelength associated with expected by products of a bevel edge clean process. The method includes cleaning the bevel edge area of a substrate and monitoring the intensity of the selected wavelengths during the cleaning for deviation from a threshold wavelength intensity. The cleaning is terminated if the deviation from the threshold wavelength intensity exceeds a target deviation.