CONTROL OF SEMICONDUCTOR MANUFACTURING EQUIPMENT - REAL-TIME FEEDBACK-CONTROL OF A REACTIVE ION ETCHER

This paper describes the development of real-time control technology f or the improvement of manufacturing characteristics of reactive ion et chers, A general control strategy is presented, The principal ideas ar e to sense key plasma parameters, develop a dynamic input-output model for the subsystem connecting the equipment inputs to the key plasma v ariables, and design and implement a multivariable control system to c ontrol these variables, Experimental results show that this approach t o closed-loop control leads to a much more stable etch rate in the pre sence of a variety of disturbances as compared to current industrial p ractice.