Predictive Solder Joint Reliability Modeling for Early Risk Assessment

Abstract

The reliability of electronic product is a very important concern for customer and product users. These electronic packages are susceptible to solder joint failure arising from CTE mismatch and thermo-mechanical stresses during thermal cycling conditions. Hence, methods to improve and predict the service life of electronic packages are important challenges for on-going research on design for reliability. A robust and accurate life prediction model [1] is an effective engineering tool to accurately predict fatigue life of the package within a short time without resorting to perform expensive and time-consuming reliability life data collection. However, the life prediction accuracy of finite element simulation models is dependent on modeling assumptions, geometrical complexity, creep constitutive model of solder and fatigue life model calculation [2]–[8]. This paper examines how the accuracy of life prediction model is established by correlating the reliability test data with predicted SED (strain energy density) values in the simulation models (Fig. 2). The optimized life prediction model is verified with the measured reliability data of different packages for its accuracy. Given that solder joint failure is one of the major electrical failures during thermal cycling testing, it is imperative to establish an accurate life prediction model (Fig. 3) and understand how different package designs and material selection affect the solder joint integrity. Based on the finite element analysis, the resulting simulation findings will add insight in enhancing solder joint reliability against thermo-mechanical loading. Early risk assessment can also be performed to identify high-risk design which requires immediate attention as well as low-risk design which can be assessed to proceed with reduced qualification plan.