US Patent 10128090 RF impedance model based fault detection

A method to detect a potential fault in a plasma system is described. The method includes accessing a model of one or more parts of the plasma system. The method further includes receiving data regarding a supply of RF power to a plasma chamber. The RF power is supplied using a configuration that includes one or more states. The method also includes using the data to produce model data at an output of the model. The method includes examining the model data. The examination is of one or more variables that characterize performance of a plasma process of the plasma system. The method includes identifying the fault for the one or more variables. The method further includes determining that the fault has occurred for a pre-determined period of time such that the fault is identified as an event. The method includes classifying the event.