Carrier transportation management system and method for internal buffer process tools

Abstract

System and method for carrier transportation management in a wafer fabrication facility ('fab') are described. In one embodiment, the fab comprises a process tool having an internal buffer for storing a plurality of carriers each containing a wafer lot and a load port for loading wafer lots into and out of the internal buffer and the method comprises determining a relative priority between a first wafer lot, which has been processed by the process tool and is stored in the internal buffer, and a second wafer lot, which is to be transported to the process tool for processing thereby; and, responsive to a notification from the process tool that the load port is available, unloading the first wafer lot from the internal buffer via the load port if the first wafer lot has been determined to have a higher priority than the second wafer lot, and transporting the second wafer lot to the process tool and loading the second wafer lot into the internal buffer via the load port if the second wafer lot has been determined to have a higher priority than the first wafer lot.