Crystallographic Characteristic Effect of Cu Substrate on Serrated Cathode Dissolution in Cu/Sn–3.0Ag–0.5Cu/Cu Solder Joints during Electromigration

Materials

Wu Yue¹  Junxi Zhang¹  Chenggong Gong¹  Chao Ding²  Hongbo Qin² 

[1] School of Materials Engineering, Lanzhou Institute of Technology, Lanzhou 730050, China;School of Mechanical and Electronic Engineering, Guilin University of Electronic Technology, Guilin 541004, China;

关键词: electromigration;    solder joint;    cathode dissolution;    crystallographic characteristic;    Cu substrate;   

DOI  :  10.3390/ma14102486

来源: DOAJ

【 摘 要 】

The crystallographic characteristic effect of Cu substrate on cathode dissolution behavior in line-type Cu/Sn–3.0Ag–0.5Cu (SAC305)/Cu solder joints during electromigration (EM) was investigated by scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and first-principles calculations. The SEM and EBSD results show that the crystallographic characteristic of Cu substrate is crucial to cathode dissolution behavior under a direct current of 1.5 × 10⁴ A/cm² at 125 °C ± 2 °C. When the (001) plane of copper grain adjacent to the Cu₃Sn/Cu interface is perpendicular or nearly perpendicular to the current direction, local cathode dissolution tips are easily formed, whereas the (111) plane remains mostly undissolved, which finally leads to the inhomogeneous cathode serrated dissolution in the substrate. The first-principles calculation results reveal that the different surface energies and energy barriers of the different crystallographic planes of Cu grains in the substrate are responsible for the local cathode dissolution tips. Adjusting the copper grain in a substrate to a crystal plane or direction that is difficult to dissolve during EM is a promising method for improving the reliability of solder joints in the future.

【 授权许可】

Unknown