PB-FREE SOLDER ALLOY COMPOSITIONS COMPRISING ESSENTIALLY TIN(SN), SILVER (AG), COPPER (CU), PHOSP

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A Pb-free solder alloy is designed from the Sn based substrate, which is a n on- toxic and environmental friendly metal. The Pb-free solder includes a composition consisting essentially of 0.3 - 0.4 weight % Ag, 0.6 - 0.7 weight % Cu, 0.01 - 0.3 weig ht % P, 0.001 - 0.3 weight % Ce, optionally 0.001 - 0.3 weight % La, and a balance of Sn, having off--eutectic melting temperatures of about 217-227 degree Celsius. 0.001 - 0.3 weight % Trace amount of Ce and / or La rare earth added to the said composition, to enhance better micro-structural stability and to reduce the coarse Sn grains in the microstructure of the solder joint formed, during Hand Soldering, Wave Soldering and Reflow Soldering in Electronics Assembly Processes.