激光植球焊点剪切强度研究及断裂途径分析

Study on shear strength and fracture path of laser ball planting solder joint

为提高激光植球焊点的可靠性,研究了不同工艺参数对激光植球焊点剪切强度的影响,分析了不同剪切情况下焊点的断裂途径。实验材料为SAC焊球,直径为500μm,以Au-Ni/P-Cu为基底,通过激光植球机进行焊点的制备。通过正交试验及极差、方差分析法发现激光功率对焊点剪切强度影响最大,推断出工艺参数的最优组合。通过改变剪切参数,用电子显微镜(SEM)对焊点的断裂面进行观察,分析其断裂途径,发现降低剪切高度及加快剪切速度均会使焊点的断裂途径发生变化,焊点由完全的韧性断裂向脆性断裂转变。本研究可为提高激光植球过程中焊点的强度及不同外界条件下器件的使用提供一定参考。

In order to improve the reliability of laser ball solder joint,the influence of different process parameters on the shear strength of laser ball planting solder joint and the fracture path of solder joint under different shear conditions were analyzed.Sac solder ball with a diameter of 500 μm is used in the experiment and Au-Ni/P-Cu is used as substrate.The solder joints are prepared by laser ball planting machine.Through the orthogonal test,range and variance analysis,it is found that the laser power has the greatest influence on the shear strength of the solder joint,and the optimal combination of process parameters is inferred.Through the change of shear parameters,the fracture surface of the solder joint is observed by electron microscope(SEM) and its fracture path is analyzed.It is found that the fracture path of the solder joint is changed by reducing the shear height and accelerating the shear speed and the solder joint will change from complete ductile fracture to brittle fracture.It provides a certain reference significance for improving the strength of the solder joint in the process of laser ball planting,and the use of devices under different external conditions.