Provided is a method of designing an optical metrology system for measuring structures on a workpiece wherein the optical metrology system is configured to meet a plurality of design goals. The design of the optical metrology system is optimized by using collected design goal data in comparison to the set plurality of design goals. In one embodiment, the optical metrology system is used for stand alone metrology systems. In another embodiment, the optical metrology system is integrated with a fabrication cluster in semiconductor manufacturing. At least one parameter determined from a diffraction signal measured using the optical metrology system is transmitted to the fabrication cluster. The at least one parameter is used to modify at least one process variable or equipment setting of the fabrication cluster.