A critical review of constitutive models for solders in electronic packaging

Owing to their superior electrical, thermal, and mechanical properties, solder joints are the most widely used interconnection materials in electronic product packaging. Because the failure of the whole electronic packaging is often induced by the failure of solders, modeling and simulation of solder joint performance are quite important in ensuring the quality and reliability of electronic products. In fact, the accuracy of reliability design of electronic packaging is dependent on accelerated reliability tests, material constitutive models, finite element modeling, and fatigue-life prediction models. Here, the material constitutive model plays the most important role in the development of electronic reliability design because the stress, strain, and strain energy density adopted in finite element modeling and fatigue-life prediction are all computed and derived from the constitutive model. In this work, the constitutive models developed for simulating the complex stress and strain response of solders are critically reviewed. To make the description concise and comprehensive, the constitutive models were categorized into two types: the constitutive models with and without the definition of yield surface. The prediction capabilities, application scope, merits and shortcomings, and objective suggestions for the further development of constitutive models for solders in electronic packaging are proposed.