Thermally actuated colloidal tip SU-8 scanning probes

This study presents significant advancements in microfabrication techniques for developing probes with diverse tip geometries and microspheres attached to probe tips for various applications. We introduce a novel method for transfer of spherical microparticles onto probe tips. First, the microparticles were assembled within cavities bulk-etched into (100) oriented single crystal silicon and subsequently the scanning probes were patterned using SU-8 as the structural material. Upon sacrificial layer etching, SU-8 scanning probes were released with spherical microparticle tips at the distal end of the canti- lever. Additionally, we explored the integration of bimorph electrothermal actuators for precise probe actuation. Notably, our bimorph thermal actuator demonstrates superior displacement at lower voltages compared to the existing literature. The use of SU-8 as the probe material simplifies the fabrication process and enhances the device's biocompatibility. This property makes it particularly suitable for biomedical applications, extending the potential impact of this research beyond the scope of the current study.