Bi-Directional Assembly of Boron Nitride µ-Platelets by Micro-Molding for Advanced Thermal Interface Materials

With dramatically growing demand for highly complicated, high power-consumed 3D stacked integrated circuit electronics, the advancement of effective thermal management has become a key technology to secure both performance and stability. To ensure better heat management of integrated microelectronics, especially pursuing unconventional devices assembled on a sheet of paper or plastics, more feasible and effective heat management is inevitable. In this study, the mechanically robust and bi-directionally thermal conductive material are presented by micro-molding with boron-nitride (BN) microscale platelets (µ-platelets) dispersed in the polymeric matrix. Micro-pattern-induced bifurcation of assembly orientation of the BN µ-platelets and bi-directionality of heat conduction characteristics are observed. The bifurcated orientations of the BN µ-platelets are optimized by the geometry of the micro-pattern and unit size of the platelets with the assistance of particle-fluid simulation. Indeed, exceptionally enhanced thermal conductivities through both directions: 6.9 W m⁻¹ K⁻¹ in the through-plane and 7.4 W m⁻¹ K⁻¹ in the in-plane, respectively are achieved. It also exhibits flexibility with a minimum radius of curvature ≈1 mm and the capability of conformal contact to diverse morphologies to stably secure heat flow even in mechanically deformed device structures. The developed TIM can be applied to high-power, high-temperature, and mechanically deformable application environments of 3D-integrated electronics.