Design and fabrication of low-loss horizontal and vertical interconnect links using air-clad transmission lines and through silicon vias

In this paper we present the design and fabrication of air-clad planar transmission lines and TSVs that can be used as horizontal and vertical chip-chip interconnects. Performance improvement by using heterogeneous air-clad dielectric is presented for these two types of interconnect structures that establishes the basic motivation for fabricating these structures. The design data is verified by performing simulation using 3D full-wave solver HFSS. We outline the process flow for air-clad transmission lines and TSVs in detail. Several challenges in the fabrication of air-clad structures are also discussed.