Multivariable dynamic modeling and plasma-oriented advanced process control of nonlinear reactive sputtering

This thesis investigates the nonlinear reactive sputter process in a novel way: both from the control-theoretical side and from the plasma-physical side.The plasma behavior is explicitly considered for the process modeling and for the design of the control system to establish steady-state plasma conditions. By use of one of the presented control systems an unstable operation point of the process can be stabilized, which enables high deposition speed and a stoichiometric thin film subject to steady-state plasma conditions. In this framework, the plasma state is either defined by the self-bias voltage or the electron density. The application of the Multipole Resonance Probe allows to control the electron density as a quantity that directly characterizes the plasma state.