Integrated Power Inductors and Capacitors Enabled by a Multilevel Molding Process

We summarize here recent advancements toward integration of electronic passives for electrical power converters. Microscale inductors and capacitors with three-dimensional, free-standing copper traces are formed via a multi-layer molding and electroplating process. This capability creates two complementary routes for passives microfabrication: (a) high inductance density air-core inductors with vertically-stacked windings; and (b) inductors and capacitors with ferromagnetic and dielectric nanoparticles deposited through capillary-driven self-assembly. Several designs of air-core inductors are tested with inductance densities >100 nH/mm² and quality factors >20. A suspended transmission line is encapsulated in NiFe₂O₄ magnetic nanoparticles for 25% greater inductance and no detriment to the quality factor up to 100 MHz. Deposition of BaTiO₃ dielectric nanoparticles between nested capacitor electrodes yields up to a 6x increase in capacitance.