Capacitive micro force sensors manufactured with mineral sacrificial layers

In this work a prototype of micro force sensor of range μN...mN is presented. Instead of the traditional piezoresistive strain sensing through thick-film resistors used for higher forces, a more effective principle is used: measurement of beam displacement rather than strain. A design of a cantilever sensor with capacitive electrodes, optionally coupled with an electrostatic force cancelling to achieve higher sensitivity, is proposed and discussed. The structuration of the device is achieved in alumina with thick- films and mineral sacrificial layers (MSL), and the resulting sensor properties are promising. The composition and dissolution of the sacrificial paste is of high importance, and is the cornerstone of the presented research. Key words: Force sensor, Capacitive, Thick-film, Sacrificial layers, Mineral