Silicon cantilevers with piezo-resistive measuring bridge for tactile line measurement

In this article a variety of applications of a microelectromechanical system (MEMS) including a cantilever with an integrated piezo-resistive bridge is described. With the low-noise integrated piezo-resistive bridge a resolution in the nanometer range is possible. This sensor obtains a typical resolution in the vertical displacement of 2 nm (due to noise floor Delta f = 1.6 kHz). Due to the low spring constant of D = 1 to 10 N/m, measurements with contact forces of < 100 mu N can be realized. This allows a non-destructive examination of polymer structures. Furthermore, the sensor is characterized by a high eigenfrequency (> 2.7 kHz), a slight mass (a parts per thousand 0.1 mg) and a measuring velocity of up to 10 mm/s. The important applications of the MEMS cantilever are fast inline control of building panels, measurement of optical structures, inside measurement of fuel injection nozzle micro holes. Furthermore, it is possible to provide different tip geometries (e.g. cone or ball) at the end of the cantilever for an ideal surface measurement.