Standardization of a shear test method for lead-free solder paste chip joints

The electronics industry is moving to replace Pb-based solder with Pb-free solder because of the growing environmental regulations governing the use of lead. Solder joints made from Pb-free solder paste do not yet have an evaluation method to classify its mechanical properties such as shear strength. In this study, we reflowed solder joints from Sn–3.0Ag–0.5Cu solder paste. To standardize the shear test method, we measured the shear strength of the solder joint of a 2012 ceramic chip at a shear rate of 3–60 mm/min and a shear height of 10–380 μm using different shaped shear jigs. We statistically analyzed the optimum number of shear tests by calculating the accumulative average value, standard deviation, and width of the confidence interval. The fracture surface was examined by scanning electron microscope and discussed in terms of the shear conditions.