Systems and Methods for Extracting Process Control Information from Radiofrequency Supply System of Plasma Processing System

A first radiofrequency signal generator is set to generate a low frequency signal. A second radiofrequency signal generator is set to generate a high frequency signal. An impedance matching system has a first input connected to an output of the first radiofrequency signal generator and a second input connected to an output of the second radiofrequency signal generator. The impedance matching system controls impedances at the outputs of the first and second radiofrequency signal generators. An output of the impedance matching system is connected to a radiofrequency supply input of a plasma processing system. A control module monitors reflected voltage at the output of the second radiofrequency signal generator. The control module determines when the reflected voltage indicates a change in impedance along a transmission path of the high frequency signal that is indicative of a particular process condition and/or event within the plasma processing system.