Numerical Simulation Of Dynamic Fracture Behavior On Lead-free Solder

With the continuous development of electronics packaging technology, solder joint package structure is being more widely applied in electronic packaging fields. At same time, joints are getting smaller, but demanding to their mechanical properties is becoming higher and higher, the destruction of joints will directly lead to the failure of electronics. So the research on package reliability has been focus on solder joint reliability, while the solder joint fracture problem is one of the important aspect, which isvery worthy of study.Lead-free solder belongs to the typical viscoplastic material. Load ratehas a major influence on lead-free solder behavior of stress and strain. This article established a continuous and separate type model of solder joints based on rate-dependent Johnson-Cook material model, using the theory of fracture mechanic and cohesive element method in the ABAQUS software to simulatethe lead-free solder crack propagation process of type I. Apply different load rates, to explore loading rate, the impact of the fracture toughness of the material structure, such as the separation of the solder joints crack propagation behavior.The results show that at a low temperature SAC305 lead-free solder is closer Sn37Pb than SAC405; For the continuous model, the crack propagation speed of Johnson-Cook visco-plastic material model is slower than the speed of linear elastic material, and the results of Johnson-Cook material model is closer to the real situation. The load rate for the fracture behavior of SAC305 lead-free solder has a significant impact. Under different load rate, the growth rate of the solder joint stress are different; Fracture toughness is an important factor affecting the solder crack growth conditions, the greater the fracture toughness, crack generation of energy needed per unit area, the slower crack growth rate.