A run-to-run control framework for VLSI manufacturing

A run-to-run (R2R) control framework has been developed for application to supervisory control of semiconductor manufacturing processes. This generic framework, which is being developed for eventual transfer to industry, is one component of a multi-level control system that includes real-time equipment and process control as well as pseudo-real-time process control elements operating in conjunction with the R2R controller. The framework is compliant with existing trends and standards in industry. At the heart of the framework is a generic cell controller implementation that serves to support the R2R control algorithm and coordinate control and information flow between the various R2R control modules. This implementation provides for the easy incorporation of commercially available software into the control scheme. The R2R control algorithm incorporates a multi-thread process control and optimization scheme; this scheme supports the complementary utilization of any number of control and optimization modules resulting i n more complete coverage of the control and optimization space than traditional single-thread methods. The R2R control algorithm has been implemented in the control of a reactive ion etcher. The implementation incorporates an optimization thread based on in-situ process models, and an SPC-based control thread. Results indicate a 70% improvement in reaching and maintaining target parameter values when compared with an open loop system.