Experimental comparison of model-based and conventional pressure control for a plasma reactor

Pressure control in a plasma reactor system is used to experimentally compare nonlinear process-model-based-control, internal model control and conventional proportional-integral (PI) control. The experimental system consists of a single slice plasma etch reactor with an attached radio frequency generator and a vacuum pump. The RF discharge forms the plasma. The control system includes an one inch stepping motor powered butterfly type exhaust valve.