β-Sn的晶粒取向对电迁移过程中铜柱焊点的影响。

The Effect of Grain Orientation of β-Sn on Copper Pillar Solder Joints during Electromigration.

作者信息

Xu Kexin, Fu Xing, Wang Xinjie, Fu Zhiwei, Yang Xiaofeng, Chen Si, Shi Yijun, Huang Yun, Chen Hongtao

机构信息

Department of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China.

Department of Reliability Design Research, China Science and Technology on Reliability Physics and Application of Electronic Component Laboratory, Guangzhou 510610, China.

出版信息

Materials (Basel). 2021 Dec 24;15(1):108. doi: 10.3390/ma15010108.

DOI:10.3390/ma15010108

PMID:35009255

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8745900/

Abstract

The grain orientation of Sn-based solder joints on copper pillars under the combined action of electron wind force and temperature gradient greatly affects their electromigration damage. The copper pillars with Sn-1.8Ag lead-free solder on the top was subjected to a current density of 1.5 × 10 A/cm at 125 °C to study the electromigration behaviors. The grain orientation was characterized by scanning electron microscopy (SEM) equipped with electron backscattered diffraction (EBSD) detector. Metal dissolution and voids formation in the cathode as well as massive intermetallic compounds(IMC) accumulation in the anode were observed after electromigration. Closer examination of solder joints revealed that the Sn grain whose c-axis perpendicular to electric current may have retarded Cu diffusion to anode and IMC accumulation. In addition, the newly formed CuSn exhibited preferred orientation related to the electric current direction.

摘要

在电子风力和温度梯度的共同作用下，铜柱上锡基焊点的晶粒取向对其电迁移损伤有很大影响。顶部带有Sn-1.8Ag无铅焊料的铜柱在125℃下承受1.5×10 A/cm的电流密度，以研究其电迁移行为。通过配备电子背散射衍射（EBSD）探测器的扫描电子显微镜（SEM）对晶粒取向进行表征。电迁移后观察到阴极处的金属溶解和空洞形成以及阳极处大量金属间化合物（IMC）的积累。对焊点的进一步检查表明，c轴垂直于电流的Sn晶粒可能阻碍了Cu向阳极的扩散和IMC的积累。此外，新形成的CuSn呈现出与电流方向相关的择优取向。