Enhancing Pb-free Solder Joint Reliability

When the electronics industry first began to discuss the mandatory move to lead-free manufacturing, it was widely believed that the transition would also enable more reliable solder joints. Bulk testing of tin-silver-copper systems showed increased strength, which should deliver joints with higher strength –most notably creep strength-- as compared to SnPb solder joints. However, with certain package types, lead-free assemblies seem to be more vulnerable to failures. To find out why, one must examine why a solder joint fails and then analyze how to amend the problem.