Cost-effective RF interposer platform on low-resistivity Si enabling heterogeneous integration opportunities for beyond 5G

We present a highly-scaled packaging and system-integration RF interposer platform on low-resistivity Si (15-25 Ωcm). The heterogenous platform has been processed and characterized by measurements in the frequency range from 10 MHz to 110 GHz, revealing an interconnect insertion loss less than 0.3 dB/mm at 100 GHz and Qmax above 40 for integrated inductors. The excellent performance of the RF Si interposer enables high frequency interconnects between the ICs and the partial matching network in the package. The narrow pitch of the μbumps further enables flip-chip performance up to 500 GHz, allowing for heterogenous integration of multiple mm-wave ICs in different technologies, together with integrated high-Q passives, as well as antennas-in-package for RF to beyond-5G applications.