ABSTRACT
Plasma reactors intended for surface treatment, etching, thin-film deposition, or other forms of plasma processing use a variety of specialized techniques and devices designed to facilitate processing or to improve the quality and uniformity of the result. When implementing a control strategy for plasma processing, it is necessary to measure and control the flow rate of the working gas. During plasma processing, and particularly during its initial and final phases, the evolution of reaction products and the gas load on the pumping system may vary. There exist some plasma-processing applications, including sputtering and plasma chemical vapor deposition (PCVD), for which it is useful to place the workpiece at a location remote from the target that produces sputtered atoms, or from the plasma–chemical reactor that produces the precursors responsible for PCVD. In plasma reactors intended for deposition, etching, or surface treatment, the active species responsible for these forms of plasma processing are convected along with the neutral working gas.
