The cracking potential of TSOPs (thin small-outline packages) was estimated under impact loading, similar to the process that triggers TSOP fracture during the mold ejection process of plastic-encapsulated microelectronic packaging. It was found that the susceptibility of TSOPs to impact-induced damage is more influenced by the existence of residual stresses than surface defects of the die, which result from the wafer back-lapping process. The experimental results showed that diamond particle-induced crater marks, which contribute to introducing residual stresses to particular sites of the die back surface, can be more critical for determining impact strength of TSOPs than grinding-induced scratch marks. The present work also showed that chemical tempering of the back surface of the die is very effective for suppressing such impact-induced damage of TSOPs under very low impact loads.