The Influence Of Trace Elements On The Wettability And Interface Structure Of Low-silver SnAgCu Solders

At present,the development trend of electronic packaging technology is toward miniaturization and refinement.Brazing filler is the most commonly used material for electronic device packaging,and the wettability and reliability of solder become one of the focuses of attention.In addition,after the comprehensive performance of the solder is guaranteed,the cost of reducing the alloy of the solder is also the goal that the industry has been pursuing.SnAgxCu0.7(x=0.1?0.3?0.5?0.8?1.0),SnAg0.1Cu0.7Nix(x=0.03?0.05?0.07?0.09),SnAg0.1Cu0.7Gex(x=0.03?0.05?0.07?0.09),SnAg0.1Cu0.7Cex(x=0.01?0.05?0.1?0.2)solder alloy were prepared by metallurgy method.The properties of the solder were analyzed using the metallographic microscope,DSC,universal material testing machine,wet balance,and scanning electron microscope.The changes of the solder interface under statics,droping and high temperature and high humidity conditions were observed,and the change of the interface activation energy was analyzed.Based on SnCu0.7,the additive amount of Ag was 0.1%,0.3%,0.5%,0.8% and1.0%,and the microstructure,melting characteristics,mechanical properties and weldability of the solder alloy were analyzed.It found that when the content of Ag was0.1%,the melting property of the alloy was better and cost-effective.The effects of microalloy elements(Ni,Ge and Ce)on the microstructure,melting properties,mechanical properties and wettability of the solder were analyzed.When the Ni content of the alloying element is 0.05%,the wetting and wettability of the solder alloy is better.When the addition amount of Ce is 0.05%,the fluidity and mechanical properties are better.The optimum addition amount of microalloying elements Ni,Ge,and Ce were 0.05%.Through the addition of different types and contents of microalloying elements,the welding interface was analyzed after static conditions,drop tests,and high temperature and humidity tests at different time,and the appearance and structure of the interface changed.The results show that under different experimentalconditions,with the 0.05% Ni,0.05% Ge or 0.05% Ce,the growth of the intermetallic compound at the interface is controlled,and the thickness is relatively uniform and smooth.When the Ce is 0.05%,the growth activation energy Q of the interfacial compound is 78.90 KJ/mol.The maximum activation energy of the interface is better.SnAg0.1Cu0.7Ce0.05 has the best overall performance.