Cu/Co metaconductor based highly energy-efficient bonding wires for next generation millimeter wave electronic interconnects

In this work, Cu/Co superlattice coated wires are introduced as highly energy-efficient bonding wires for next generation broadband millimeter wave electronic interconnect applications. The non-ferromagnetic/ferromagnetic metal based nano superlattice conductor, the so-called metaconductor, is especially designed to suppress its skin effect, thus greatly reducing its series RF resistance at the frequency of interest, such as at millimeter wave frequencies for broadband 5G communication and high-speed computation applications. The alternatingly electroplated superlattice wire consists of 10 pairs of Cu/Co on a gold core wire with a thickness of 150 nm/25 nm, respectively. As a test vehicle to show the effectiveness of the Cu/Co metaconductor for highly energy efficient electronic wire bonding interconnects, an airlifted inductor with a one port coplanar waveguide feeding structure is designed, fabricated, and characterized. A solid Cu counterpart with the same geometric dimension is implemented for comparison. In 10 ~ 45 GHz, the Cu/Co superlattice coated wire shows a maximum 70 % RF resistance reduction and a 56 % Q factor improvement compared with the Co counterpart.