US Patent 7340377 Monitoring a single-wafer processing system

A method of monitoring a single-wafer processing system in real-time using low-pressure based modeling techniques that include processing a wafer in a processing chamber; determining a measured dynamic process response for a rate of change for a process parameter; executing a real-time dynamic model to generate a predicted dynamic process response; determining a dynamic estimation error using a difference between the predicted dynamic process response and the expected process response; and comparing the dynamic estimation error to operational limits.