Reliability Study Of ZnO Nanoparticles Reinforced SnAgCu Lead-Free Solder

Sn-Ag-Cu lead-free solder is the most popular solder substituting for traditional Sn-Pb solders currently as modern electronic products are developing toward portability,miniaturization,and high performance.According to the requirements of lead-free solder performance for the electronic packaging industry,the wettability,melting point,intermetallic layer thickness and intermetallic layer structure of nano/micron ZnO particle reinforced Sn-3.0Ag-0.5Cu composite solder are investigated.The research conclusions are as follows:(1)Analysis of the melting characteristics and wettability of the composite solder shows:The influence of nano-ZnO on the melting point of SAC305 is not significant;the addition of reinforcing particles can significantly improve the wettability of Sn-3.0Ag-0.5Cu lead-free solder matrix.The amount added is in the range of 0?2.0 wt.%.The nano-composite solder reach a maximum at the ZnO content of 0.5 wt.%whereas the micron ZnO composite solder reach a maximum at the content of 1.5 wt.%.The wettability of nanocomposite solder is better than microcomposite solder.At the optimum value,the wetting angle of the nano ZnO particulate composite solder is reduce by 76.66%with respect to the Sn-3.0Ag-0.5Cu.(2)ZnO particles can inhibit the growth of Intermetallic compound(IMC)layer.The IMC layer growth of nano-composite solder is inhibited mainly by inhibiting atomic diffusion and adsorption to the surface of the IMC grains to inhibit grain growth.Since the surface of the crystal grains in the body adsorbs the reinforcing phase particles,the surface free energy is lowered,which makes it stable,thereby suppressing the growth of crystal grains.(3)After the addition of the ZnO particles,the microhardness of the composite solder is increased.The nanocomposite solder reach a maximum at a ZnO content of 0.5 wt.%,and the micron ZnO resurfacing solder reach a maximum at a content of 1.5 wt.%.The maximum value of the nano/micron ZnO composite solder hardness is 12.4 HV and 12.0 HV,respectively,which increase by 10.71%and 7.14%with respect to the Sn-3.0Ag-0.5Cu,respectively.The ZnO particles further increase the hardness of the solder joint by the strengthening effects of dispersion refinement and fine grain strengthening,and hinder the movement of dislocations in the solder to increase the dislocation density to further increase the microhardness of the solder joint.(4)Comprehensive analysis,the reliability of nano-composite solder is better than micro-composite solder,and the optimal addition amount of nano-ZnO particles is 0.5 wt.%.