Jianq Chyun IP Office
Method for controlling beta-tin orientation in solder joints
A method for controlling the beta-tin crystal orientation in solder joints is provided. The method is suitable for joining metallization pads using a solder containing tin and silver. By adjusting the silver content in the solder within a specific range of equal to or more than 2.5 wt. % and less than 3.2 wt. %, the [001] axes of beta-tin crystals in the solder is aligned to be in the direction parallel with a solder/metallization pad interface substantially. Electromigration-induced solder deformations and metallization pad consumption can be significantly reduced when solder joints have such a microstructure. Additionally, the undesired Ag3Sn plates in the solder matrix can be avoided accordingly.
Yuan Ze University
B
B23K
inventional
Cheng-En Chih-Nan Bo-Zong
Ho Chen Chen