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

Abstract 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.