US Patent 6999164 Measurement system cluster

Systems and methods are disclosed for measuring semiconductor wafers in a fabrication process using one or more of a plurality of measurement systems. A measurement system cluster is provided having a plurality of such measurement systems, along with a system for transferring wafers to one or more of the measurement systems according to one or more selection criteria. Measurement systems may be selected for use based on availability and throughput capabilities, whereby overall system throughput and efficiency may be improved within the required accuracy capabilities required for measuring process parameters associated with the wafers.