研究Sn Ag Cu Fe焊点的本构方程,采用拉伸测试拟合本构模型的9个参数。基于有限元模拟应用Anand模型分析WLCSP30器件Sn Ag Cu Fe焊点的应力-应变响应。结果表明,器件最大应力集中在拐角焊点上表面,Sn Ag Cu Fe焊点应力值明显小于Sn Ag Cu焊点。基于疲劳寿命预测模型,证实微量的Fe可以显著提高Sn Ag Cu焊点疲劳寿命,因此Sn Ag Cu Fe可以替代传统的Sn Pb应用于电子封装。
The Sn9Zn eutectic alloy is the nontoxic lead-free solders alternative having a melting temperature which is closest to that of the eutectic SnPb alloy. In order to improve the properties of SnZn lead-free solders, 0-0.5 wt.% of rare earth Er was added to the base alloys, and the microstructures were studied. Results showed that the addition of rare earth Er could enhance the wettability of SnZn solders, with 0.08%Er addition, the spreading area gavc an 19.1% increase. And based on the mechanical testing, it was found that the tensile force and shear force of SnZn-xEr solder joints could be improved significantly. Moreover, the oxidation resistance of SnZn0.08Er solder was better than that of SnZn solder, in addition, it was found that trace amounts of rare earth Er could refine the microstructures of SnZn solders, espe- cially for Zn-rich phases, and excessive amount of rare earth Er led to a coarse microstructure.
