Plasma etching is a technology essential to microelectronic circuit fabrication. Dry plasma etching is accomplished by starting with a relatively inert molecular gas such as carbon tetrafluoride, and allowing it to interact with radiofrequency glow discharge plasma to create active species capable of reacting chemically with the layer to be etched. Plasma etching requires much lower quantities of specialty chemicals/gases than are required for wet chemical etching, and the very small quantity of reaction products from the etching process results in minimal environmental impact. Plasma etching has been used to produce vacuum transistors, and even to fabricate moving parts on a scale of a few microns, including levers, wheels, and electrostatic motors. The plasma parameter strategy is capable of leading to better understanding of physical processes in the plasma and in the etching process itself. The chapter discusses the nomenclature and methods used to transfer a pattern from a mask to a layer to be etched by plasma-related etching processes.