Soldering alloy, cream solder and soldering method
US5918795A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1997 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | Jan 31, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K35/025
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The present invention relates to a soldering alloy composed mainly of Sn and free from lead which is a toxic substance. An addition of a small quantity of Ag to the soldering alloy can fine the alloy structure, minimize structural changes of the alloy and increase thermal fatigue resistance thereof. An addition of a small quantity of Bi to the soldering alloy lowers the melting point and improves the wettability thereof. Further, an addition of a small quantity of Cu restrains the growth of intermetallic compounds in the bonding interface between a copper land and the solder. Furthermore, an addition of a small quantity of In improves the elongation property and thermal fatigue resistance of the alloy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.