焊点形态对表面贴装元件无铅焊点可靠性的影响
Effects of Solder Joint Shape on Reliability of Lead-free Solder Joint
郝秀云， 杨 洁， 王玉鹏
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作者单位：南京信息职业技术学院机电学院, 江苏 南京 210046
中文关键字：焊点形态； 表面贴装元件； 焊点可靠性； 无铅钎料； 润湿角
英文关键字：solder joint shape; surface mount components; solder joint reliability; free-lead solder; wetting angle
中文摘要：表面组装焊点的几何形态是影响焊点可靠性的重要因素之一。本文采用有限元方法，重点讨论了润湿角对低银Sn2.5Ag0.7CuRE焊点的应力应变分布和热疲劳寿命的影响，并与Sn37Pb和Sn3.8Ag0.7Cu钎料焊点的热疲劳寿命进行了对比分析。研究表明，片式元件的理想接头形态为微凹形；在此形态下，与Sn37Pb和Sn3.8Ag0.7Cu钎料焊点相比，低银Sn-2.5Ag-0.7CuRE钎料的表面贴装元件焊点具有更高的热疲劳寿命。这一结果对于焊点的优化设计及新型无铅钎料的研制具有一定的指导意义。
英文摘要：The geometry shape of solder joint can effect the reliability of solder joint. The effects of wetting angle on the stress-strain distribution and thermal fatigue life of Sn2.5Ag0.7CuRE solder joint were investigated by nonlinear finite element method, and the thermal fatigue life of Sn37Pb and Sn3.8Ag0.7Cu was comparatively analyzed. The results show that the ideal shape is retuse. Furthermore, Compared with Sn37Pb and Sn3.8Ag0.7Cu solder joint, the SnAgCuRE solder joint has the highest thermal fatigue life. The results are of importance to optimize the design of solder joint and develop lead-free solder.