This paper presents an innovative approach to develop highly sensitive 3D force sensors. In order to increase the
probing sensitivity by using a material with low Young´s Modulus, a novel force sensor design based on SU-8 polymer
is realized. Therefore, a low cost fabrication process is developed accompanied by design studies and an estimation of
mechanical properties of the deforming elements. This paper will present the fabrication process as well as a
distinguishing set of test results, analytical results, and simulations on the characterization of the presented SU-8 force
The novel SU-8 design consists of an SU-8 boss-membrane with integrated piezoresistive elements. The SU-8
membranes are structured using photolithography. The SU-8 micromechanical structures are characterized to determine
film stresses, bending stiffness, displacement of the stylus, and breaking points. Included in these tests are measurement
of the stress behavior at different process steps and simulation of stress distribution in the membrane at different
directions of loading. In addition a comparative analytical investigation of the structures is carried out particularly with
regard to the displacement of the stylus.
Using SU-8 as sensor material, due to low Young´s modulus, promises sensitivity much higher than what is obtained
using conventional silicon force sensors.