| With the development of integrated circuit chips in the direction of high power and high integration,the heat dissipation performance of traditional electronic packaging materials can no longer meet current needs.Diamond/Cu composite materials have high thermal conductivity and low expansion characteristics,and have become a hot spot in the research of new generation electronic packaging materials.However,due to the non-wetting of diamond and copper,the two-phase interface is weakly bonded,and the ideal high thermal conductivity composite material cannot be obtained.This subject uses spark plasma sintering(SPS)and air pressure infiltration process,combined with diamond surface metallization and copper matrix alloying method to introduce carbide interface layer to improve the interface bonding and improve the thermal conductivity of the composite material.The main findings are as follows:Using the SPS preparation method,the effect of the diamond coating process on the properties of the composite was studied.Diamond/Cu composite material was prepared by using 165?m bare diamond and pure copper powder with a volume fraction of 50%as the raw materials.The best process obtained was:sintering temperature930?,sintering pressure 50MPa,and holding pressure for 10 minutes.On this basis,the performance of composites made of different types of coatings(Ti,Cr,W)diamonds was compared,and it was found that Cr-plated diamonds are more conducive to improving interfacial bonding.When the thickness of the Cr layer is 470nm,the interface strength of the composite material is good,the degree of densification is high,the thermal conductivity can reach 572.9W/(m·K),and the thermal expansion coefficient is 6.72×10-6/K.Using the SPS preparation method,the effects of the process of pure copper powder doped with Ti,Zr and Cr powder on the properties of the composite material were studied.The study found that doping the three powders can form a carbide layer at the interface of the composite material.When the volume fraction of the three powders reaches 3%,the thermal conductivity of the composite material reaches the optimum,respectively 562.1W/(m·K),583.2W/(m·K)and 542.4W/(m·K),At this time,the interface of the composite material is mostly metallurgical,the degree of densification is much higher than that of the undoped composite material,and the thermal expansion coefficient reaches the application standard.Compared with the preparation process of composite materials using atomized copper alloy powder,the doping preparation process is simple,the cost is low,the material performance is stable,and it is suitable for the mass production of Diamond/Cu composite materials.In addition,through the discussion of the interface thermal conductivity mechanism of the composite material,combined with the AMM model to calculate the interface thermal resistance,it was found that the appropriate thickness of the interface layer plays a key role in the high thermal conductivity of the composite material.Using air pressure infiltration preparation method,the effects of diamond coating and copper matrix alloying process on the properties of composite materials were studied.The coating(Cr)diamond and pure copper infiltration process and bare diamond and copper alloy(Cu-Zr,Cu-Cr-Zr)infiltration process can form a carbide layer at the interface of the composite material to improve the interface bonding.Combining the above two methods,it is found that the composite material prepared by Cr-plated diamond(plating thickness 180nm)and Cu-Zr alloy impregnation process has the highest thermal conductivity,up to 684.7W/(m·K).It provides a new method for the preparation of high-performance composite materials. |
PDF Full Text Request