Arrays of SU-8 microcantilevers with integrated piezoresistive sensors for parallel AFM applications

Parallel scanning with arrays of AFM cantilevers has an advantage over conventional single AFM probes because of increased acquisition speed for sample imaging. A challenge for such large arrays is the simultaneous detection of deflection of a multitude of cantilevers. In addition, conventional AFM probes lack flexibility in cantilever array design, and material conventionally used is not soft enough for some applications such as imaging cells for biology. In this paper, alternative arrays of polymer SU-8 microcantilevers with moulded tips and integrated piezoresistive sensors are fabricated to demonstrate parallel imaging of large sample areas. Cantilevers with a variety of SU-8 thicknesses ([email protected]) are investigated. SU-8 cantilevers and SU-8 tips are formed at the same time by casting SU-8 into [email protected] pyramidal moulds, which are created by anisotropic KOH etching. Further, photolithographic processes and metal deposition, such as lift-off and electroplating, are combined to define piezoresistive sensors on top of fabricated SU-8 cantilevers. SU-8 cantilever arrays are tested in parallel contact-mode scanning of surfaces and topography on micro/nano structures. Parallel imaging with SU-8 cantilever arrays is carried out by data acquisition and analysis of resistance changes in the integrated sensors.