Highly Energy Efficient and Electromagnetic Interference Immuned Coaxial Through-Substrate-Vias (cx-TSVs) for Millimeter Wave Applications

A coaxial through-substrate-via (cx- TSV) based on a Cu/Co metaconductor is presented for the first time, which exhibits low RF loss and good electromagnetic interference (EMI) immunity, thereby ensuring high signal and power integrity and reliable system packaging for millimeter wave applications. The low loss is attributed to the metaconductor configuration, while the cx-TSV ensures EMI immunity and reliability. The study simulates a ground-signal-ground (GSG) type cx-TSV, with an inner conductor diameter of 4.7 micrometers, consisting of 5 pairs of 300 nanometers Cu and 50 nanometers Co, a dielectric layer diameter of 16.5 micrometers, a dielectric constant of 2.25, and a unit cell length of 10 micrometers, as a test vehicle. The study also implements a solid Cu TSV counterpart with the same via diameter of 4.7 micrometers and a solid Cu cx-TSV with the same geometric dimension for comparison. The results show that the proposed Cu/Co metaconductor-based cx-TSV design achieves an insertion loss of 0.39 dB/mm and an isolation of 18 dB at 33 GHz, which are improvements over the solid copper TSV counterpart. These findings indicate the potential of the proposed design for advanced applications requiring high performance and reliability in millimeter-wave regimes.