AlN: An Engineered Thermal Material for 3D Integrated Circuits

Abstract Aluminum nitride (AlN) is a promising material for thermal management in 3D integrated circuits (ICs) due to its high thermal conductivity. However, achieving high thermal conductivity in AlN thin films grown at low temperatures on amorphous substrates poses significant challenges for back‐end‐of‐line (BEOL) compatibility. This study reports high cross‐plane thermal conductivities approaching 90 Wm⁻¹K⁻¹ for sub‐300 nm‐thick AlN films sputter‐deposited at low temperatures (<200 °C) on ordinary SiO₂ substrates. The correlations between cross‐plane and in‐plane thermal conductivity, texture, grain size, oxygen content, Al:N atomic ratio, and thermal boundary conductance of these films are explored. These findings reveal the crucial role of grain orientation alignment in achieving high thermal conductivity and high thermal boundary conductance. A method is introduced to effectively monitor the thermal conductivity of the AlN thin films using X‐ray diffraction. This study offers valuable insights that can aid in the implementation of an effective thermal management material in the semiconductor production line.