Silicon-core Coaxial Through Silicon Via for Low-loss RF Si-interposer

In this letter, a new low-loss and low-cost through silicon via (TSV) process is presented. The proposed silicon-core coaxial via (S-COV) process is very simple and time-saving compared with a conventional TSV. In this structure, a metal-coated silicon-pole is used as a vertical interconnect instead of a fully filled metal via. The depth of the fabricated S-COV is 120 μm and the minimum diameter of the signal core and dielectric gap to ground are 40 and 20 μm, respectively. In the well-matched condition, the measured insertion loss of the single S-COV is 0.053 dB at 10 GHz.