Effective Thermal-Mechanical Modeling of Solder Joints

An effective, two-staged global/local finite element (FE) modeling technique is proposed for characterizing the thermal-mechanical behaviors of solder joints in area array type packages under the temperature cycling. It consists of two essential features: the employment of a compact global FE model in the global analysis, and a two-staged, hybrid constitutive modeling strategy for solder materials, which is to apply the elastoplasticity constitutive law for solder joints in the global analysis during the first temperature rise while utilize the viscoelasticity in the rest of periods. To substantiate the proposed modeling technique, a large-scaled, 3-D FE model with a very fine mesh is constructed as a baseline model. The result derived from the proposed approach is then accordingly compared with those of the baseline solution. From these comparing results, it turns out that the proposed 3-D global/local FE modeling technique is an effective mean for simulating the thermal-mechanical behaviors of solder joints.