Soldering methods and compositions
US6340113B1 · kind B1 · utility
Inventors
Key dates
| Filing date | Jan 8, 1999 |
| Grant date | Jan 22, 2002 |
| Priority date | — |
| Expiry date | Jan 8, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/043
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Soldering methods and compositions are disclosed to provide electrical connections between surfaces with reduced likelihood of short circuits or solder-starved joints. Two component solder compositions are employed to preferably form “metallic foam” joints upon heating. In one embodiment, bimetallic particles are disclosed which fuse together rapidly reducing the likelihood of reflow-related solder joint faults. The methods and compositions of the present invention can also reduce the potential for thermal fatigue and other solder joint failures in electronic devices following fabrication because the porous solder joints relieve plastic constraints and lower the average tensile joint stress. In one preferred embodiment, solder compositions are employed which are composed of particles of a first metal coated with a second metal. Alternatively, the compositions can include particles of a first metal surrounded by a salt solution or suspension of a second metal. The metals are chosen such that their individual melting points are higher than the melting points of the alloy or alloys formed when they are combined. Upon heating of such coated particles, melting occurs at the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.