Fatigue-resistant lead-free alloy
US5938862A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1998 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | Apr 3, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C13/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A lead-free solder alloy suitable for forming solder joints of a surface-mount integrated circuit device, such as a flip chip. The solder alloy has a sufficiently low liquidus temperature to achieve desirable reflow properties at temperatures of 240.degree. C. and less, and is therefore compatible with integrated circuit processes. The solder alloy has a sufficiently high solidus temperature to ensure that solder joints formed with the alloy exhibit suitable mechanical properties at application temperatures up to 150.degree. C. when mounting a component to a laminate substrate. The solder alloy generally contains, in weight percent, about 7 to about 11% indium, about 2.5 to about 3.5% silver, and about 0.5 to about 1.5% copper, the balance tin and incidental impurities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.