外文翻译-无铅微焊点机械强度试验仿真分析.doc

本科毕业设计(论文) 外文翻译（附外文原文） 学 院： 机械与控制工程学院 课题名称： 无铅微焊点机械强度 试验仿真分析 专业(方向)： 机械设计制造及其自动化 （机械装备设计与制造） 班 级： 机械11-2班 学 生： 罗统深 指导教师： 代宣军 日 期： 2015年3月10日 Reliability and Failure Analysis of Lead-Free Solder Joints Michael Meilunas and Anthony Primavera, Ph.D. Universal Instruments Corporation Binghamton, New York Steven O. Dunford Nokia Mobile Phones Irving, Texas Abstract This paper provides a comparison of the air-to-air thermal cyclic reliability and associated failure modes of second levelinterconnects in lead-free, 1.27 mm pitch, 256 I/O BGA devices with eutectic tin-lead assemblies. Both electrolessnickel/immersion gold (ENIG) and copper OSP test board surface finishes were included in this study. The assemblies weresubjected to two different 0/100oC accelerated thermal test conditions. Solder joint failures were determined with in-situeventdetection and verified by resistance measurements, x-ray, cross-sectioning and dyepenetration. Elemental analysis wasperformed on selected failed solder joints. Theresults of the experiment indicate that the average solder fatigue life of thelead-free alloys investigated was higher than that of the tin-lead solder. However, the fundamental crack propagationbehavior of the lead-free alloys was not the same as the tin-lead samples. Failure analysis revealed that intermetallicformation, fatigue crack characteristics, and solder fatigue propagation mechanisms associated withthe lead-free alloys were not common to the tin-lead samples. In addition, lead-free solder joints evaluated in rigorous failure analysis show uniquefeatures such as stress voids, crackpath redirection around intermetallic formations, vertical cracking and spalling of portionsof the solder joint, which are not common in traditional tin-lead BGA solder joints Introduction T