Method for controlling beta-tin orientation in solder joints
US8702878B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 2011 |
| Grant date | Apr 22, 2014 |
| Priority date | — |
| Expiry date | Jun 21, 2032 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K1/0016
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.