Low pressure, nonequilibrium, electric discharge (plasma) processes are used in the microelectronics industry to deposit and etch thin films. Plasma enhanced chemical vapor deposition (CVD) enables film deposition at low temperatures and can provide new materials with special material and electronic properties. Plasma etching is presently used for etching of masking materials, silicon, silicon-containing materials, compound semiconductors, and metals. In the production of a typical microchip, ten or more steps may involve plasma etching. In this industry, processing is rarely automated to a high degree. Real- time monitoring and control could aid in exploiting the fine geometry transfer available in plasma etching as well as increase process yields by introducing dynamic treatment of process variables. The PIs plan a comprehensive study of mathematical models and process control strategies for plasma etching, reactive ion etching and CVD. Plasma deposition and etch rates are affected by a large number of process variables including gas composition, pressure, temperature, reactor geometry, electric discharge frequency, and power. To model and develop control strategies for such systems both theoretical and experimental studies are planned. A research etcher utilizing a radial flow configuration with analytical systems and data acquisition has already been constructed and the PIs plan to construct laboratory-scale CVD apparatus. Based on experimental results, physico-chemical models will be developed and verified followed by the formulation and implementation of both dynamic and steady state control strategies.
