Solder Joint Reliability of Sn-Ag-Cu BGA and Sn-Pb Solder Paste

In the transition to lead-free, components suppliers need carry the product of lead-free and lead components. This could cause the extensive logistic problems in manufacturing. Therefore, it is necessary to study the solder joint character of Sn-Ag-Cu BGA and Sn-Pb solder paste. In this study, the results of solder joint shape and reliability evaluations of PBGA (Plastic ball Grid Array) lead-free package assembled to PCBs (Printed Circuit Boards) with eutectic Sn-Pb solder paste was presented. The lead-free package was assembled under various reflow profiles and PCB surface finish. The peak temperature of reflow soldering of 210, 225 and 235 °C with the soak profile was used. The PCB surface finish included HASL (Hot Air Soldering Level) and ENIG (Electroless Ni/Immersion Au). The different types of solder joints, both as-reflowed and after reliability test, were examined using optical microscope, transmission X-Ray. The reliability test of TTC (Thermal Torsion Cycling) and ATC (Accelerated Thermal Cycling) was used. Detailed failure analysis will also be presented.