Dimensional metrology in the macroscopic range with sub-nanometre resolution
Nanomeasuring machines are devices for solving various positioning and measuring problems in a range of several millimetres with sub-nanometre resolution. These devices are used for positioning, probing and measurements. The combination of this machine with a scanning force microscope leads to improved quality in the calibration of standards. The measurement accuracy and stability of the scanning force microscope are important for the achievable measurement uncertainty. Many systems are influenced by the creep, hysteresis and bending of the included piezo actuators. A scanning force microscope head with a combined deflection detection system that comprises an interferometer and a beam deflection system was developed. Due to this system, it is possible to simultaneously measure the displacement, bending and torsion of the cantilever with only one focussed beam. An additional high-speed piezoelectric actuator for the vertical motion of the cantilever was integrated and is controlled by the bending signal. The outcome of this additional control system is a much higher scan speed. The interferometer system can be used for precise measurement of the vertical cantilever motion. Hence, non-linearity and hysteresis in the actuator do not affect the measurement. The device was used for several calibration measurements on step height and lateral standards. This article deals with the set-up, function and application of a scanning force microscope head for dimensional metrology with the nanomeasuring machines.