Mechanical characterization of Sn-3.5Ag solder joints at various temperatures

Deformation studies on eutectic Sn-Ag solder (Sn-3.5Ag in wt percent) joints were carried out at a range of temperatures using a rheometric solids analyzer (RSA-III). Various performance parameters were evaluated with this equipment by subjecting geometrically realistic solder joints to shear loading at various temperatures (25, 75, 100, 125, and 150°C) with a nominal joint thickness of ∼100 μm and 1×1 mm solder joint area. Mechanical properties such as shear stress versus simple shear-strain relationships, peak shear stress as a function of rate of simple shear-strain and testing temperature, and creep parameters were evaluated to gain a better understanding of the parameters contributing to thermomechanical fatigue.