Synthesis of Face to Face Partially Fused Carbon Nanotubes for the Improvement of Thermal Management in 3D Die Stacking

Smaller thermal resistance between stacked chips will help reduce the junction temperature of 3D integrated circuit (3D-IC) under the same operating condition. Carbon Nanotubes (CNTs), as one of the materials with extremely high axial thermal conductivity, are suitable for such an application and compatible with wafer-level processes. However, since CNTs grow from the catalyst and have a free end in most cases, the free end is difficult to form proper thermal contact with the other side. In this paper, a novel method to synthesis CNTs simultaneously from both sides of the microchannel between stacked chips is proposed.

I. Introduction

3D-IC has been widely used nowadays in various kinds of electronic devices. Minimizing the thermal resistance between stacked chips could help reduce the operation temperature at a certain working frequency. To increase the thermal coupling between stacked chips, CNTs has been considered and found effective to improve the thermal conductivity of Thermal Interface Material (TIM) [1].