Performance analysis of carbon nanotube based global interconnects and through silicon vias for 3D ICs

Abstract

The IC technology was a major breakthrough toward miniaturisation of device, system reliability, faster communication, cheap production cost and lesser power consumption for logic operation within a chip. A three-dimensional IC (3D IC) allows the assembly of disparate and multiple heterogeneous dies in a single chip. However, the performance of today s ICs are primarily dominated by the speed of interconnect and through silicon via (TSV). With the miniaturization, the resistivity of Al and Cu interconnects and TSVs are rapidly increasing that results in the electromigration induced voids and hillocks formation. It has a severe impact on the overall performance of an IC. In order to mitigate these problems, the carbon nanotubes (CNTs) have recently emerged as a promising material for interconnects and TSVs. In a 3D IC, the TSVs are primarily used to connect the vertically stacked dies. The first phase of the thesis primarily focuses on the investigation and analysis of thermo-mechanical stress and electromigration reliability of TSV based 3D interconnects. The test structures of TSV filled with Cu and multi-walled carbon nanotube (MWCNT) have been modelled. The CNT bundled interconnects have displayed less stress induced electromigration effects when compared to Cu at high current densities ( and#8805; 10 10A/m2), and the Cu based interconnects fail too early. The second phase of the work presents an accurate numerical model to obtain the propagation delay, and crosstalk noise of high-speed on-chip interconnects. The structure of on-chip interconnect was considered as non-uniform, and the skin effect was included. The lossy coupled non-uniform interconnects were modelled by finite-difference time-domain (FDTD) technique. The proposed interconnect model was fast and accurate in predicting the crosstalk induced performance analysis of lossy coupled non-uniform interconnects at high frequencies. The third phase of thesis demonstrates the reliability of CNT bundled interconnects in terms of propagation delay, crosstalk noise