Reliability of gull-wing and leadless packages subjected to temperature cycling after rework

An experimental study was conducted to determine the effect of rework on the quality and reliability of surface mount solder interconnects. The test vehicle included thin small outline packages (TSOPs) and 2512 resistors assembled onto circuit cards with Sn3.0Ag0.5Cu and Sn63Pb37 solders. The rework process entailed the removal and replacement of the TSOPs and resistors. Reworked assemblies were then subjected to a temperature cycling test. Test results indicated that rework did not degrade the reliability of the TSOP solder attachments, but it decreased the thermal fatigue life of 2512 resistors down by 80% due to the decreased and uneven solder joint heights created by the hand-soldered rework process. Solder interconnect material changes caused by the rework process were not observed to be a significant factor in reliability.