J. Qu

Publications (2)0.94 Total impact

• Article: Creep and Fatigue Behavior of SnAg Solders With Lanthanum Doping

  Min Pei, Jianmin Qu
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  ABSTRACT: In this paper, extensive testing was conducted to study the effects of Lanthanum (La) doping on the creep and fatigue behavior of SnAg lead free solder alloys. Variables considered in this paper include doping amount, aging temperature, and aging time. The experimental data show that rare earth element (RE) doping increases SnAg solders creep resistance by about 15%. Meanwhile, RE doping does not affect thermal aging behavior of the solder alloy. A microstructure dependent Anand viscoplastic model is proposed to capture the RE doping effect on the creep behavior. Good agreement between the model predictions and experimental data are obtained. In addition, fatigue tests were performed with bulk specimen. It is found that La doping increases the fatigue life by about five times. The optimal doping level for better fatigue performance is around 0.1%.
  IEEE Transactions on Components and Packaging Technologies 10/2008; · 0.94 Impact Factor
• Conference Proceeding: Constitutive modeling of lead-free solders

  M. Pei, J. Qu
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  ABSTRACT: Solders are used extensively as electrical interconnects in microelectronics packaging. Because of environmental concerns, lead-based solders are being replaced by Sn/Ag and Sn/Ag/Cu based solder materials. Since the thermomechanical reliability of modern electronic devices depends on, to a large extent, the fatigue and creep behavior of the solder joints, it is imperative to understand the deformation behavior of these new lead-free solders. This study conducted extensive thermomechanical testing on several commercial lead-free solder alloys. Anand viscoplastic model was used to describe the behavior of these materials with new curve fitting techniques. A modified Anand models was proposed that can yield a more accurate description of lead-free solders.
  Advanced Packaging Materials: Processes, Properties and Interfaces, 2005. Proceedings. International Symposium on; 04/2005