Tuning thermal expansion coefficient of copper-multilayer graphene thermal management materials through tailoring interfacial microstructure

Abstract

The lifetime of the electronic packaging system is shortened due to the mismatch in the coefficient of thermal expansion (CTE) between the substrate and the packaging material. Developing packaging materials with tailored CTE has become one of the most challenging topics. Herein, the CTE behavior of copper matrix composites filled with high volume fraction of multilayer graphene (MLG) is tuned by tailoring the interfacial curvature, which is further illustrated through multi-scale numerical simulations. The results show that a) the interfacial curvature radius decreases with increasing MLG content for Cu-MLG composite materials; b) a gradually decreased CTE from 16.8 × 10−6/°C to 15.3 × 10−6/°C at temperatures from 300 °C to 900 °C is displayed in the Cu-48 vol% MLG composite, which is different from the increased CTE performed in the pure copper and Cu-30 vol% MLG composite materials; c) a higher constraint stress is generated by MLG with a smaller curvature radius in Cu/MLG interface region as revealed from Finite Element modeling; d) the atomic vibration amplitude of copper decreases when introducing MLG in the copper grain boundary region as identified from the Molecular Dynamic Simulations. This finding makes the Cu-MLG composite a promising candidate for applying in the thermal management of electronic packaging systems.