Solder microstructure and intermetallic interface evaluation between Sn-3.5Ag-1.0Cu-xNi lead free solder under long time thermal aging (x: 0, 0.05, 0.2, 0.5)

Sn-3.5Ag-1.0Cu-xNi (x: 0, 0.05, 0.2, 0.5) solder alloy has been developed to improve properties and microstructure of Sn-3.5Ag-1.0Cu based solder. The composite solder were synthesized via the powder metallurgy route which consist of blending, compacting and sintering process. The sintered solders were characterized for it melting temperature, SEM-EDX analysis was done to confirm the homogeneity of sample element distribution and X-Ray diffraction (XRD) analysis was conducted to see the presents of some phases. XRD analysis of sintered sample showed the presents of Ni3Sn4 and Ni3Sn2 phases. Solders were melted on copper substrate at 250°C for one minute on hot plate and aged at 150°C from 0 to 400 hours. The microstructure of the solder and the growth of IMC formation were studied under Scanning Electron Microscope (SEM) and EDX. The phases formed were studied under SEM-EDX. The SEM results show the presence of Cu6Sn5, Cu3Sn and Ag3Sn intermetallic in the Sn-3.5Ag-1.0Cu solder and Sn-3.5Ag-1.0Cu-xNi solder.