银含量对跌落条件下无铅焊点疲劳寿命和失效模式的影响  

Influence of Silver Content on Fatigue Life and Failure Mechanism of Lead-free Solder Joints Under Drop Conditions

作　　者：杨金丽[1] 雷永平[1,2] 林健[1] 肖慧[1] 

机构地区：[1]北京工业大学材料科学与工程学院,北京100124 [2]哈尔滨工业大学先进焊接与连接国家重点实验室,哈尔滨150001

出　　处：《材料工程》2013年第12期74-79,共6页Journal of Materials Engineering

基　　金：北京市自然科学基金(3102002)和重点项目基金(KZ20110005002)资助;现代焊接生产技术国家重点实验室课题基金资助项目(51275006)

摘　　要：对3种不同Ag含量材料(Sn-3.0Ag-0.5Cu,Sn-1.0Ag-0.5Cu,Sn-0.3Ag-0.7Cu)的焊点进行跌落实验,实验中施加的加速度载荷为峰值3200g,脉冲持续时间1ms的半正弦波形加速度,利用电学测试、光学显微镜和扫描电子显微镜确定了失效的焊点并对失效焊点进行分析。结果表明:3种材料焊点的失效位置基本都在靠近印刷电路板(PCB)侧,BAG封装最外围4个拐角处的焊点最先失效。Sn-3.0Ag-0.5Cu,Sn-1.0Ag-0.5Cu焊点的失效模式均为脆性断裂,Sn-0.3Ag-0.7Cu为韧-脆混合断裂。且随着Ag含量的降低,金属间化合物(IMC)的厚度逐渐减小,焊点的寿命逐渐提高。Drop tests were carried out with three kinds of materials （Sn-3. 0Ag-0. 5Cu, Sn-1. 0Ag- 0.5Cu and Sn-0.3Ag-0.7Cu） ,respectively. Half-sine acceleration loads was applied in the experiment, the peak value of half sine acceleration and pulse duration were 3200g and lms. The failure position of solder joint was identified and analyzed using electrical test, optical microscope, scanning electron mi- croscope. The results show that most of the failures joints for the three kinds of materials locate at the printed circuit board （PCB） side. The solder joints at four outermost corners fail at first. And the failure modes of Sn-3.0Ag-0.5Cu and Sn-1.0Ag-0.5Cu were all brittle fractures, while the Sn-0.3Ag- 0.7Cu is brittle-ductile fracture. The thickness of intermetallie compound（IMC） gradually decreases and the life of solder joint enhances with the reduction of Ag content.

关 键 词：银含量 跌落冲击 失效机理 疲劳寿命 

分 类 号：TG115.28[金属学及工艺—物理冶金]