Calibration of height-measuring probes

Many industries now require control of surface heights to sub-micrometre precision. The systems that calibrate quality control instruments for such applications must have capability at the nanometre level, or better, and excellent traceability. Xray interferometry is currently the strongest candidate for this task. As this paper demonstrates, it is quite feasibly used in a normal standards room yet provides accuracies of better than 0.1 nm. Following a description of the preferred meirological configuration, which uses silicon monolithic devices, some features that have improved its accessibility are discussed. Particular attention is paid to sensors and actuators that may t as transfer standards to provide convenient routine calibrations. Finally, a design for a stand-alone, desk-sized instrument is presented.