Flexible parylene-based folded inductors with magnetic core

This paper presented a novel folded structure of parylene-based MEMS inductors. Parylene was chosen as the substrate material because of its good biocompatibility and flexibility. Since the entire structure is flexible, well-designed planar inductors could be simply folded into 3D structures. This novel method solves the problem of achieving high performance and avoiding complicated fabrication process at the same time. A Ni₈₀Fe₂₀ soft magnetic core was electrodeposited in the center of the coils in order to enhance the performance of inductors. Compared with planar inductors, the inductance and the maximum quality factor (Q) of three-layer inductors increased 66.2% (from 336.81nH to 559.83nH) and 241.4% (from 8.18 to 27.93), respectively. This novel MEMS folded inductors could be used in wireless power transmission system for implantable applications.