Reliability Assessment of Packaging Solder Joints Under Different Thermal Cycle Loading Rates

Abstract

In assessing the solder joint reliability using an accelerated thermal cycling (ATC) test methodology, which is widely used in the microelectronics industry, a common type of solder joint failure is the formation of fatigue cracks at the interface between the solder joints and the components. However, ATC tests are quite time-consuming and can take more than a month to complete. Hence, its efficiency has become an important issue. The parameters of the ATC test, such as temperature ramp rate and dwell time, significantly influence fatigue failure in solder joints. Fast temperature cycles can reduce the testing time, but the effects of ramp rate cause variations in solder joints' material properties and mechanics behavior due to strain rates and stress changes. Commonly used lead-free materials with high homologous temperatures induce creep-related solder joint failures. This paper used a temperature-dependent Young's modulus and Garofalo-Arrhenius creep equation to describe the solder deformation response. An energy-density-based empirical equation was used, along with the optimized mesh size in a finite-element model calculation with different solder joint geometries and packaging types such as power modules, and wafer-level chip-scale packages to determine how to accommodate the strain rate effect given various ramp rates.