Demonstration of Substrate Embedded Ni-Zn Ferrite Core Solenoid Inductors Using a Photosensitive Glass Substrate

In this work, we propose a Ni-Zn ferrite core embedding process in a photosensitive glass substrate and demonstrate the design and fabrication of substrate embedded inductors and integrated voltage regulators (IVRs) using the substrate embedded ferrite cores. We developed a ferrite core embedding process inside a vertical cavity of a photosensitive glass substrate, so that ferrite core solenoid inductors can be embedded in the substrate. The measured inductance, DC resistance and Q-factor of a 1600μm × 1500μm ferrite core inductor were 209nH, 240mOhm, 15.8 at 18.2Mhz respectively. And a 920μm × 1050μm inductor has inductance of 252nH, DC resistance of 663mOhm, and Q-factor of 16.6 at 20Mhz. The power conversion efficiency of an integrated voltage regulator module was measured up to 85.2%.