Lead-based solder alloys containing copper
US6811892B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 22, 2002 |
| Grant date | Nov 2, 2004 |
| Priority date | — |
| Expiry date | Sep 13, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24917
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A tin-lead solder alloy containing copper and optionally silver as its alloying constituents. The solder alloy consists essentially of, by weight, about 55% to about 75% tin, about 11% to about 44% lead, up to about 4% silver, nickel, palladium, platinum and/or gold, greater than 1% to about 10% copper, and incidental impurities. The solder alloys contain a small portion of CuSn intermetallic compounds, and exhibit a melting mechanism in which all but the intermetallic compounds melt within a narrow temperature range, though the actual liquidus temperature of the alloys may be considerably higher, such that the alloys can be treated as requiring peak reflow temperatures of about 250° C. or less. The intermetallic compounds precipitate out to form a diffusion barrier that increases the reliability of solder connections formed therewith.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.