Evaluation of Garofalo Creep Model for Lead-free Solder Joints in Surface Mount Components

This investigation employs four hyperbolic sine creep constitutive models to simulate the damage in Sn[3.04.0%]Ag[0.5-1.0%]Cu solder joints in flip chip (FC) model FC48 D6.3C457DC and resistor model R102 components assembled on printed circuit boards (PCBs). The creep models are proposed by Lau, 2003; Pang et al, 2003; Schubert et al, 2003 and Zang et al, 2003. The FC joints contain intermetallic compounds. All assemblies are subjected to accelerated high-temperature cycles utilising IEC Standard 60749-25 in parts. This study determines and compares the magnitude of accumulated creep strain and strain energy density generated from simulations using the varous models and evaluates the effect of using the different creep relations to quantify damage and fatigue life of solder joints. The results show significant differences demonstrating that predicted damage and fatigue life of solder joints depend on the value of creep parameters, damage index, creep model and geometry of solder joint.