Effects of Long-Term Aging on SnAgCu Solder Joints Reliability in Mechanical Cycling Fatigue
Authors: Francy John Akkara, Sinan Su, Sivasubramanian Thirugnanasambandam, Ahmad Dawahdeh, Awni Qasaimeh, Ph.D.,John Evans, Ph.D., Sa’d Hamasha, Ph.D. Company: Department of Industrial and Systems Engineering, Zebra Technologies Date Published: 9/17/2017
Abstract: For the past decade, the electronics industry has been switching to lead-free solders in the integrated circuit packages. Alloys with tin (Sn), silver (Ag) and copper (Cu) have been the most popular candidate in replacing the leaded solder joints. However, the reliability of SnAgCubased solder joints is a major challenge, especially in longterm applications. Many studies have been conducted to address the reliability issues of lead-free solder joints but without considering the effect of aging. Isothermal aging alters the structural and mechanical properties of the solder joints, which has a detrimental effect on their strength and fatigue life. This paper discusses (1) the effect of long-term isothermal aging at high temperature on SnAgCu Ball Grid Array components in high cycling fatigue (vibration), and (2) the effect of extended long-term isothermal aging at room temperature on individual SnAgCu solder joints in low cycling fatigue. The fatigue life of solder joints before and after aging was studied in both experiments. The results showed a significant impact of aging on the fatigue life of SnAgCu solder joints (i.e. the fatigue life dropped to 30% in long-term aging). In addition, only bulk solder joint failure was observed in all experiments.