The Influence Of Cu₅Zn₈ And Ag₃Sn Diffusion Barrier On Interface Reaction Of Sn-Cu Soldering

At present,due to excellent conductive and thermal conductivity,Cu is widely used as matrix material in the microelectronic packaging industry.During the solding process of microelectronic devices,the chemical reactions of Cu substrate and solder form the IMC（intermetallic compound）.This reaction process is inevitably accompanied by known to be detrimental to mechanical reliability.To overcome this issue,significant research efforts have been directed to control the thickness of IMC,In order to resolve the problem of excessive growth of IMC.In this paper,continuous and stable IMC layer as diffusion barrier layer in the reflow process of soldering.Cu₅Zn₈ diffusion barrier layer was prepared by dip welding;Ag₃Sn diffusion barrier layer was prepared by electrodeposition and heat induction.The morphology evolution of IMC on Cu,Cu₅Zn₈/Cu and Ag₃Sn/Cu substrates and the related kinetic mechanism were studied under different solding processes.（1）It is feasible to suppress the soldering interface reaction by prefabricating Cu₅Zn₈ and Ag₃Sn diffusion barrier layers.Under the same soldering process conditions,the IMC growth rate of pure Sn brazing filler metal on Cu₅Zn8/Cu,Ag₃Sn/Cu is lower than that on ordinary Cu substrate.（2）For the Cu₅Zn₈ diffusion barrier,within a certain range,the greater the thickness of the diffusion barrier,the better the effect of inhibiting the excessive growth of IMC.Through the evolution of morphology and kinetic analysis,due to the existence of Cu₅Zn₈ diffusion barrier,The process directly passes through the reaction diffusion stage and reaches the grain boundary diffusion stage,thereby slowing the growth rate of IMC and inhibiting the excessive growth of IMC.（3）The order of the Ag3Sn coating affects the growth of the IMC during the brazing process.Since Cu and Sn-plated interface will become Cu6Sn5,the Ag-Sn diffusion barrier prepared by plating Sn and then Ag plating is better.