Study On Preparation Technology And Soldering Mechanism Of TiO₂ Nanoparticles Sn-Based Composite Solder

The modern microelectronics industry is developing towards miniaturization and multifunction.It is one of the effective ways to improve the reliability of solder joint to prepare the composite solder by adding nano-reinforced phase particles in the solder alloy.In this paper,the melting point and wettability of Sn-xTiO₂/C u?x=0,0.3wt.%,0.6wt.%,0.9wt.%,1.2wt.%?respectively are studied systematically.The effects of resistivity and TiO ₂ nanoparticles doped by solder joint on the microstructure of interconnect interface and the grain growth rate of IMC generated by C u₆Sn₅ during multiple reflux welding and aging are investigated.Its main elements are summarized as follows:The results of TiO₂ nanoparticles doping on the physical properties of Sn-xTiO₂/Cu show that the melting point of the composite solder increases with the increase of the amount of TiO ₂doping,and the coherent interface between TiO₂ and?-Sn increases the melting point of the crystal.The wettability of the composite solder is due to the effect of TiO ₂ on the surface tension first and then to the decrease,while the electrical conductivity of the composite solder increases because of the lattice defects caused by the addition of TiO₂ nanoparticles.The effect of TiO₂ nano-particle doping on the liquid-solid reaction of Sn-xTiO₂/C u microjoints during reflux welding was studied.The results showed that the thickness of TiO₂layer and the growth of C u₆Sn₅ grain were obvious with the increase of brazing time.The thickness of more prism IMC layer is also increased with the increase of brazing temperature.With the increase of doping content of TiO₂ nanoparticles,the thickness of TiO₂ decreases first and then increases 0.3wt.%.The inhibition effect is obvious.The thickness of TiO ₂ layer decreases from 2.80?m to 2.45?m,and the average diameter of grain decreases from 1.43?m to 1.04?m.The effect of temperature and TiO₂ nanoparticle doping on the interfacial reaction of Sn-xTiO₂/Cu microsolder during multiple reflow and aging process showed that the thickness of IMC layer increased obviously during multiple reflow and aging process with the increase of temperature.With the increase of TiO₂ nanoparticle doping,multiple reflow and aging process IMC layer the thickness decreases first and then increases,and reaches the minimum at0.3wt.%.