As the interconnect delay exceeds the gate delay, the integrated circuit (IC) technology has evolved from a transistor-centric era to an interconnect-centric era. Conventional metallic interconnects face several serious challenges in aspects of performance and reliability. To address these issues, nanocarbon materials, including carbon nanotube (CNT) and graphene, have been proposed as promising candidates for interconnect applications. Considering the rapid development of nanocarbon interconnects, this paper is dedicated to providing a mini-review on our previous work and on related research in this field.

This paper proposes a novel differential through-silicon via (D-TSV) structure, which is filled with vertically aligned carbon nanotube (VACNT) array. Two metal pads are deposited on the sides of the surface of the proposed D-TSV to form differential signal transmission paths. The equivalent circuit model is established for the proposed D-TSV, with the frequency-dependent impedance extracted using partial-element equivalent-circuit (PEEC) method. By virtue of the equivalent circuit model, the electrical performance of the proposed D-TSV is investigated, with some design guidance presented.

We investigated the transmission characteristics of Cu/CNT composite Through-silicon via (TSV) interconnects. The equivalent lumped-element circuit model was established, with the effective conductivity employed for impedance extraction. The impacts of CNT filling ratio, temperature, and other geometrical parameters on the performance were examined. The sensitivity analysis of Cu/CNT composite TSVs was carried out. The electrical performance of Cu/CNT composite TSVs were optimized by utilizing low-permittivity dielectrics or even air-gap.