The Investigation of Electrical Characteristics for Carbon Nano-Tubes as Through Silicon Via in Multi-Layer Stacking Scheme With an Optimized Structure

Through silicon via (TSV) is the key technology for 3-D integrated circuits (3-DICs) which could vertically stack homogeneous or heterogeneous dies with the high performance and density. To evaluate the electrical characteristics of TSV at the high-frequency transmission, the skin effect and surface roughness effect are necessary to be considered. However, these effects would significantly result in the TSV equivalent resistance under the high operating frequency. Thus, it is important to investigate the carbon nano tubes (CNTs) TSV which has less skin effect intrinsically. In this work, we analyze the advantage of CNTs as TSV compared to the conventional filling materials such as copper (Cu). Furtherly, we also propose the equivalent circuit model of TSV and its multi-layer structure to simulate the electrical behaviors with different TSV pitch, height, diameter, and stacking layers by using ANSYS designer and high-frequency structure simulator (HFSS). Based on the frequency-domain analysis, it can be found that CNTs TSV has the lower frequency-dependent loss than Cu due to the lower equivalent resistance. In a summary, CNTs could be a promising TSV filling material at the high-speed transmission frequency based on our study.