Design and fabrication of flexible parylene-based inductors with electroplated NiFe magnetic core for wireless power transmission system

Integrated flexible parylene-based MEMS inductors were successfully designed, fabricated and analyzed. By elctrodeposition technique, Ni₈₀Fe₂₀ Permalloy with high permeability was acquired as the magnetic core to increase the inductance and quality factor of inductors. Using parylene as substrates, these inductors became more flexible and biocompatible. For small scale inductors, by HFSS simulation, a maximum quality factor of 51.52 was achieved at 3.10 GHz. The inductance of inductors with magnetic core was enhanced by 3.3% than those with air core. As the width of the core increased from 25 μm to 100 μm, the inductance was also increased by 11.3% maximally. For large scale inductors fabricated, the tested maximum quality factor was 110 at 6 MHz. Based on the IC compatible fabrication process, these inductors could be used in wireless power transmission system for implantable medical devices.