Preparation And Research Of High Thermal Conductivity Graphite/copper Electronic Packaging Materials

With the development of modern electronic information technology and the increasing integration of electronic chips,integrated circuits of heat per unit area increased,there is a strong requirement on the heat sinks for electronic components.The metal composite has well thermal properties,and easy processing at the same time,and becomes one of the most important research in the area.Compared with the traditional aluminum,copper matrix composites,the graphite/copper composite materials have excellent properties.Its thermal conductivity is higher than copper's,but it has a lighter density.What's more,it has a low thermal expansion,which match the electronic components and semiconductors very well.Through the high speed mixer for mixing and smashing the dendritic structures of electrolytic copper powder,we made raw material powder mix.Through vacuum hot-pressing sintering,graphite/copper composites with high thermal conductivity were made.The forming composites microstructure and the interface structure were analyzed,the properties of thermal conductivity,thermal expansion,density,porosity,flexural strength were investigated,Studies show that good combination between graphite and copper,graphite are arranged evenly;as the graphite content increases,the thermal conductivity of a direction first increased and then decreased.The thermal conductivity of c direction always decreased.Consistent with the results of numerical simulation.As the graphite content increases,coefficient of thermal expansion is declining to meet the mixing rule.When the graphite content of 60%,due to the orientation of flake graphite,excellent thermal conductivity properties of graphite in the slice direction possible,makes the ideal thermal conductivity of composite materials,thermal conductivity is 719 W/(m·K),about 1.8 times the thermal conductivity of copper,the thermal expansion coefficient is 7.6×10-6m/k,match the semiconductor electronic components well.flexural strength of 64MPa,easy processing.To further optimize the thermal conductivity of composite materials,surface modification processing of graphite.When the boron is coated on the surface of graphite,copper and graphite phase distribution in the composite metal matrix showing the complete three-dimension network structure,basic orientation of flake graphite,copper and graphite phase are linked closely together,and shows excellent thermal conductivity.With the increase of the graphite content,the thermal conductivity of a direction is increased,and the thermal conductivity of c direction is declining.When the copper is coated on the surface of graphite,the performance is better than the untreated sample of graphite.