Design of adiabatic TSV, SWCNT TSV, and Air-Gap Coaxial TSV

Abstract

High performance three-dimensional (3D) through silicon via (TSV) interconnects are important for reliability, choice of the filler material is also a critical issue as thermal incompatibility, electromigration, and high resistivity are still a bottleneck. In this paper, single wall carbon nanotube (SW-CNT) bundles as a prospective filler material for TSV are investigated compared to conventional filler materials like Cu, W, and poly-silicon. It is found that SW-CNT bundles exhibit unique electrical, thermal, and mechanical characteristics that can be used to fabricate better TSV interconnects. Moreover, performance comparison between Air-Gap Based Coaxial TSV and conventional circular TSV are presented. The comparison shows that the air-gap TSVs reduce the overall parasitic capacitance and the overall energy loss compared to the conventional circular TSV or conventional coaxial TSV. In addition, TSV-based ADIABATIC logic based on the adiabatic switching principle is presented and analyzed. ADIABATIC logic is a design technique for minimizing the energy dissipation. Its major limitation is the requirement for passive components, which cannot be efficiently integrated into current generation ICs. TSV-based 3D heterogeneous integration may enable efficient integration of these passive elements, which were not practically feasible in the past due to technology limitations.