Intelligent Control of Chemical Etch Processes

Chemical etching is sensitive to a number of process variables which need to be maintained in a certain relationship to achieve good product yields. The chemical kinetics and mass transport properties of the process constitute a complex nonlinear dynamics system. These dynamics are quite involved and not easily modeled, yet the qualitative behavior of the process can be naturally stated in the form of rules. Besides the mix management control problem, an inverse problem of identification occurs in the form of a required capability for fault diagnosis.