Development of three-dimensional inductors using plastic deformation magnetic assembly (PDMA)

On-chip inductors are critical for enabling portable power-efficient wireless communication systems. Existing on-chip spiral inductors based on conventional planar integrated-circuit fabrication technology suffer from substrate loss and parasitics, and have relatively large footprints. In this paper, we discuss the development of two types of on-chip three-dimensional (3-D) inductors - a vertical spiral inductor and a solenoid inductor - by using a 3-D assembly process called plastic deformation magnetic assembly. Prototype vertical spiral inductors and solenoid inductors have been fabricated and tested. Experimental results show that the vertical spiral inductors can achieve better performance and a smaller footprint than the in-plane ones.