Reliability of tin-lead balled BGAs soldered with lead-free solder paste

This paper will describe tests of the interconnect reliability of BGA components with tin-lead bumps soldered with lead-free solder paste during temperature cycling. Tin-lead BGA components soldered with tin-lead solder paste and lead-free BGA components soldered with lead-free solder paste were used as a reference. The lead-free solder used was eutectic tin-silver-copper, Two kinds of surface finishes were used on the printed circuit boards (PCB), an immersion gold over electroless nickel and an organic solderability preservative. The test PCBs were temperature-cycled for 2500 cycles in the range of - 40degreesC to + 125degreesC and they were continuously electrically monitored during the cycling. The results of the temperature cycling test showed that lead-containing BGA components soldered with lead-free solder paste don't show any serious reliability risks and can actually withstand temperature cycling stresses better than entirely lead-free BGA assemblies.