Additive fabrication of a 3D electrostatic energy harvesting microdevice designed to power a leadless pacemaker

This paper presents the development of a process enabling to fabricate complex three-dimensional nickel microdevices. The possibilities offered by this new process are highlighted by the fabrication of an original electrostatic MEMS energy harvester designed to power a leadless pacemaker. The fabrication principle is based on the repetition of three main steps: the micromolding of a structural material (nickel), the electrodeposition of a sacrificial material (copper) and a mechanical planarization of the layer. Several solutions to overcome the major challenges of this original fabrication process are presented, as for example the conception of a dedicated instrumentation for polishing. This new process has enabled us to fabricate a first three-dimensional prototype of the electrostatic MEMS made of 10 layers of nickel for a total thickness of 200 µm with a minimum in-plane pattern size of 10 µm.