A novel wafer level high Q planar inductor using Ni-Zn ferrite/BCB composite thick film

A novel integrated passive devices fabrication technique which combines wafer level packaging, bulk Si etching and stencil printing technologies to prepare silicon based inductors with high density and high-quality factor is presented. A series of high-quality inductors with Ni-Zn/BCB composite magnetic core is designed and fabricated with two-step back-etching and stencil printing technologies on low resistive silicon wafer. By using this technology, the inductance density of inductors is enhanced together with the high quality. Compared to the normal inductors, the inductors with backside magnetic composite cores demonstrate significantly higher inductance density, increasing by 42% in average. The measured Q factor of 363 nH inductor with backside magnetic composite cores reaches 8.9 at 30.2 MHz.