板级封装焊点中热疲劳裂纹的萌生及扩展过程  

Crack Initiation and Propagation in On-Board Packaging Solder Joint during Thermal Fatigue

作　　者：林健[1] 雷永平[1] 赵海燕[2] 鲁立[2] 

机构地区：[1]北京工业大学,北京100124 [2]清华大学,北京100084

出　　处：《稀有金属材料与工程》2010年第A01期15-19,共5页Rare Metal Materials and Engineering

基　　金：北京市属市管高等学校人才强教计划资助项目

摘　　要：采用试验观测和数值模拟相结合的方法研究表面贴装板级封装焊点在热疲劳过程中的裂纹萌生及扩展规律。结果表明,在热疲劳过程中,焊点上存在着3个典型的热疲劳裂纹萌生位置,其中器件与钎料的交角附近区域最容易发生裂纹萌生。这与数值模拟分析得到的焊点在热疲劳过程中所产生的非弹性应变分布规律基本一致。无铅钎料焊点相对于锡铅钎料焊点具有相对较长的热疲劳寿命;焊盘尺寸较小时,热疲劳裂纹扩展速度相对较大。这与焊点中的等效非弹性应变数值具有较好的一致性。The crack initiation and propagation in on-board packaging solder joint during thermal fatigue test was investigated by experimental and numerical method together. In this experiment the lead-less resistance of 3216 and the PCB of FR4 were selected. And two kinds of land shapes and two kinds of solder materials （including SnPb eutectic solder and lead-free solder SAC305） were considered. Some conclusions are drawn from the study： during thermal fatigue test there exist three typical locations where the crack often initiates in the solder joint. And the crack initiation mostly occurs at the comer portion between the resistance and the solder, which meets well with the simulating results of the distribution of inelastic strain in solder joint during thermal fatigue test. Moreover the lead-free solder joint has a longer thermal fatigue lifetime than SnPb eutectic solder joint. And crack growth velocity is larger in the solder joint with a smaller land shape. These can also be proved by the equivalent inelastic strain created in solder joint.

关 键 词：表面贴装结构 焊点 热疲劳 无铅钎料 

分 类 号：TG405[金属学及工艺—焊接]