Multivariable dynamic modeling and plasma-oriented advanced process control of nonlinear reactive sputtering
PhD Thesis
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Beschreibung
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.
Autor*in
Christian Wölfel
Christian Woelfel is postdoctoral researcher at Ruhr University Bochum, Germany. In his work, he combines the fields of control engineering and plasma science to develop an advanced plasma-oriented control strategy for vacuum processes. His research interests are focused on the modeling and control of physical systems against the background of interdisciplinary research themes that include plasma-based processes, process instrumentation and control theory.