Solderability of Sn-0.7Cu/Si3N4 lead-free composite solder on Cu-substrate

Reinforcing high performance ceramic particulates is an effective approach to improve solderability of lead-free Sn-0.7Cu solder. Various weight percentage compositions (0.5, 1.0, and 1.5) of Silicon Nitride (Si3N4) reinforced in Sn-0.7Cu solder were developed using powder metallurgy (PM) routes to investigate their solderability properties on copper (Cu) substrate. The solderability performances of the new composite solder will be determined and analyzed based on their contact angles on Cu substrate, including interface intermetallic compound (IMC) layer thickness and IMC phases formed for different Si3N4 ratios. Results also show an improvement in solderability of the Sn-0.7Cu/Si3N4 composite lead-free solder with optimum wettability achieved by 1.0 wt.% Si3N4. The minimal average decrease in IMC layer thickness and the formation of the different shaped of scallops figuring the IMC layer were observed. X-ray diffraction (XRD) also revealed the decreasing peak intensity of Cu6Sn5 phases with Si3N4. Overall, the entire range of composition of Si3N4 into Sn-0.7Cu monolithic solder use in this study indicated an enhancement of solderability performances on Cu-substrates.