Magnetically oriented 3D-boron nitride nanobars enable highly efficient heat dissipation for 3D integrated power packaging

Abstract

Increasing power density and miniaturization in 3D packaged power electronics demand innovative thermal management. Yet, the thermal performance of electrically insulated packages for power electronics is currently limited by the ultralow thermal conductivity of conventional thermal interface materials (TIMs) and their poor ability of directing heat to heat sink. Herein, we have prepared highly thermally conductive and electrically insulating TIMs composite based on boron nitride nanobars (BNNB). The polar characteristics of B-N bond in the BNNB outer tube wall-derived h-BN nanosheets facilitates the adsorption of magnetic particles. Modulating the arrangement of 3D-BNNB by an external magnetic field improves the thermal conductivity of composite up to 3.3 W m-1 K-1 at a concentration of 40 wt%, 17.8 times higher than the pure epoxy and also exhibiting significant anisotropy. Moreover, the composite shows a high stiffness of 510 MPa and a high resistivity of 27.2 MΩ·cm, demonstrating excellently mechanical and electrically insulating characteristics. Infrared thermography results show that the surface temperature of the composite depends on the orientation of BNNB and its interfacial interaction with the epoxy resin. The magnetic field-oriented modulation of 3D-BNNB can offer a promising solution to achieve the efficient thermal management of 3D integrated power packaging.