High-Q on-chip inductors embedded in wafer-level package for RFIC applications

Wafer level packaging (WLP) technology has been used to integrate high-Q inductor on Si substrate. These inductors consist of a thick Cu electroplated rerouting to reduce series resistance and a thick dielectric layer to separate the inductors from Si substrate. The measured results show that the peak O-factor is 30 at 4 GHz for a 0.77 nH inductor, which is good agreement with the simulated performance by HFSS. Therefore, this technology realizes embedded high-Q inductors in WLP and can improve the performance of RF system.