Force calibration of stylus instruments using silicon microcantilevers

Modelling, fabrication and testing of a piezoresistive silicon cantilever sensor is described which is designed for the transfer of force standard to commercial tactile probing instruments. Cantilever deflection and piezoresistive strain gauge output voltage are measured in dependence on loading from 1 to 250 μN revealing small residuals from linearity as well as low scatter around the average of the slopes obtained from 44 calibration runs. A procedure is developed and tested by which the force setting of a surface profiler can be referred to deflection and strain gauge output voltage curves generated by tracing a calibrated cantilever sensor along its axis. Force calibration can be demonstrated within ranges of 10-160 μN and 1-200 μN by the evaluation of deflection and strain gauge output voltage curves, respectively, at corresponding uncertainties of 50 nN to 0.8 μN and 12 nN to 1.0 μN.