US Patent 7809459 Advanced-process-control system utilizing a lambda tuner

An advanced process control (APC) system. The APC system comprises a database for receiving process data from a measurement tool for a plurality of process runs and for storing the process data. A lambda tuner determines a tuned-lambda value corresponding to a process-capability-index value based on upper and lower process control limits and statistics derived from the process data. A process-run controller updates a recipe value based on the received process data and the tuned-lambda value.