Stress and aging minimization in photoplastic AFM probes

Photostructurable epoxy based resists, like SU-8, are soft materials with a Young’s Modulus around 4 GPa, which makes them particularly suitable as base material to fabricate Atomic Force Microscopy (AFM) probes for non-destructive analysis of fragile samples such as biological materials. In this work, it is shown how by introducing an appropriate processing step consisting of a hard bake, the built-in stress gradient of the final structure was considerably reduced. This improved probes properties such as initial bending and aging and proved the epoxy based resists as good candidates for the low-cost fabrication of micromechanical systems (MEMS) and devices in general.