Inkjet printing of a polymeric vibration damper for MEMS application adopting a step-reticulation process

In the frame of additive manufacturing techniques, inkjet printing (IJP) has gained great attention both from the academic and industrial point of view, for its customization, cost-effectiveness and simplicity, in contrast to more traditional patterning techniques, i.e. lithography. IJP could be flanked in the industrial manufacturing of parts of MEMS. In particular, since MEMS are constituted of mechanical parts, they are subjected to undesired vibrations that can degrade the device. In particular, polymers are optimal material candidates for vibration damping applications. The idea of the work was to demonstrate the possibility to adopt IJP for the production of a polymeric vibration damping layer on a floating spring of a MEMS device. In depth characterization of the polymeric ink is provided as well as a jetting characterization that helped the optimization of the printing process. A common reported issue of IJP is the impossibility to reproduce perfectly vertical walls, due to drops spreading when impacting the substrate. We tried to tackle this issue by proposing an alternative process, improving the verticality of the printed pattern walls. Printing was transferred to patterned MEMS and device characterization is proposed, in terms of how the printed polymeric layer can alter or not the mechanical properties of the spring. The work highlights how IJP can be adopted to produce components of devices, avoiding the use of expensive techniques.