Methods and apparatus for monitoring a process in a plasma processing system by measuring impedance

Abstract

A method for in-situ monitoring a process in a plasma processing system having a plasma processing chamber is disclosed. The method includes positioning a substrate in the plasma processing chamber. The method also includes striking a plasma within the plasma processing chamber while the substrate is disposed within the plasma processing chamber. The method further includes obtaining a measured impedance that exists after the plasma is struck, the measured impedance value having a first value when the plasma is absent and at least a second value different from the first value when the plasma is present. The method also includes correlating the measured impedance value with an attribute of the process, if the measured impedance value is outside of a predefined impedance value envelope.

Dependencies are inferred from the claim text.