Development of a Cantilever calibration device

The measurement of small forces is required in various fields of science such as biology or physics. A common way to measure forces in the range of nano newton is to utilize AFM-Cantilevers as force sensors. Therefore it is necessarry to know the stiffness of the cantilever. Due to the manufacturing tolerances, each cantilever needs an individual calibration. The state-of-the-art calibration method with the lowest uncertainty is to measure the force-displacement curve whose slope corresponds the stiffness of the cantilever. In this article a novel device is presented that works according to this method. It uses an interferometer to measure the cantilever displacement and a custom load cell to measure the force. The load cell was calibrated in two different ways which lead to similar results. Finally, the measurement of a soft cantilever's stiffness is presentet to demonstrate the capabilities of the device.