A Silicon Molded Metal Transfer Process for On-Chip Suspended Power Inductors

In this paper, a novel silicon molded metal transfer process is developed to build on-chip suspended thick-winding inductors for high-frequency power management applications. In the proposed process, a silicon mold wafer coated with a heat-depolymerizable sacrificial layer is fabricated and used as the electroplating mold for thick-winding inductors formation; a simple transfer process is developed to release the inductors from the mold wafer and integrate the inductors with power IC chips. On-chip suspended power inductors with 65 μm thick windings are fabricated. The increased winding thickness leads to a more than 3 times reduction in DC resistance compared with inductors built by other suspended inductors fabrication techniques.