Low-cost fabrication of PMMA and PMMA based magnetic composite cantilevers

We present a simple and low-cost fabrication process for microcantilevers from both pure Polymethylmethacrylate (PMMA) and magnetic PMMA composites with maghemite nanoparticle concentrations up to 3 vol.% (12 wt.%). The fabricated cantilevers have lengths of 30 - 300 μm, widths of 14 μm and a thickness of 3 μm. The presented fabrication process consists of structural layer patterning by hot embossing, removal of the residual layer by a deep ultraviolet (DUV) exposure step through a partially transparent mold and a sacrificial layer etch to release the suspended microstructures. Process parameters including hot embossing temperature and pressure have been studied. The optimized parameters for pure PMMA are 180° C and 2370 N/cm² and for magnetic composite with 3 vol.% nanoparticle concentration 195°C and 2660 N/cm². The molded cantilevers show a well transferred pattern and a sharp side wall profile.