Mixed product run-to-run process control - An ANOVA model with ARIMA disturbance approach

A novel run-to-run control algorithm based on a dynamic analysis of variance (ANOVA) approach is proposed to deal with run-to-run (RtR) control of a high mixed operation, i.e., many different products are manufactured in many different tools. The conditions of different tools and products are identified based on the ANOVA analysis of the system output. A dynamic term in the form of an autoregressive integrated moving average (ARIMA) disturbance model is included in the process model to characterize the run-to-run disturbances such as drift, shift and/or some other unknown disturbances of different tools. It is shown from the study below that controller performance can be improved by introduction of the dynamic term, especially for products which are produced only occasionally. This makes it highly suitable for mixed product control system. An industrial example is also included to demonstrate superiority of this approach.