Study on microstructures and tensile properties of active solder alloy

Active solder is a novel lead-free solder with the addition of titanium and/or rare earth elements. Because rare-earth metals have a stronger affinity for oxygen than most metals and tend to reduce metal oxides via formation of rare-earth oxides, compared with conventional lead-free solder, active solders have many advantages, such as bonding and soldering without flux and without pre-plating, which can greatly reduce soldering steps and cost, and it was used in packaging and assembling for electronic devices, such as materials bonding between semiconductor/metal/ceramics. But for the applications of active solder, detailed information about its microstructures and mechanical properties is absent, which is very crucial for the process mechanics based reliability analysis and prediction. In this work, the characteristics of strain rate of active solder alloy (Sn-3.5%Ag-3%Ti-Ce) were investigated and tensile tests were achieved by six-axis micro-tester under the different strain rate conditions. The microstructures of active solder alloy were investigated by SEM and the distribution of elements were analyzed by energy-dispersive x-ray (EDX). Compared with the conventional lead-free solder Sn96.5Ag3Cu0.5, active solder alloy showed a bit worse mechanical properties which should be improved so as to increase the mechanical reliability for applications in electronic packaging.