Experimental characterization of coaxial through silicon vias for 3D integration

Coaxial through silicon via (TSV) technology is gaining considerable interest as a 3D packaging solution due to its superior performance compared to the current existing TSV technology. By confining signal propagation within the coaxial TSV shield, signal attenuation from the lossy silicon substrate is eliminated, and unintentional signal coupling is avoided. In this paper, we propose and demonstrate a coaxial TSV 3D fabrication process. Next, the fabricated coaxial TSVs are characterized using s-parameters for high frequency analysis. The s-parameter data indicates the coaxial TSVs confine electromagnetic propagation by extracting the inductance and capacitance of the device. Lastly, we demonstrate the coaxial TSVs reduce signal attenuation and time delay by 35% and 25% respectively compared to the shield-less standard TSV technology. In addition, the coaxial interconnect significantly decreases electromagnetic coupling compared to traditional TSV architectures. The improved signal attenuation and high isolation of the coaxial TSV make it an excellent option for 3D packaging applications expanding into the millimeter wave regime.