Evaluation of drop reliability of Sn–37Pb solder/Cu joints using a high speed lap-shear test

This study provides a framework for evaluating the drop reliability of solder joints using a high-speed lap-shear test. The test specimens employed here were Sn–37Pb/Cu under bump metallization (UBM) solder joints and were aged for 120 h at different temperatures (120, 150, and 170 °С) to examine the effects of aging. We tested them at different loading speeds in the range of 0.01–500 mm/s. A careful analysis of the stress–strain graphs attained from the tests, coupled with characterization of the fracture surfaces, discloses that the fracture mode shifts from ductile to brittle as the loading speed escalates. A map of the fracture mode shows that how readily the mode transition with the loading speed occurs can be directly translated into the drop reliability of the solder joint, disclosing that the drop reliability would deteriorate as the aging temperature increases possibly due to the increased IMC thickness. These results underscore the utility of the experimental methodology adopted in this study to evaluate the drop reliability of solder joints.

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