Lead-free solder alloy and solder reflow process
US6767411B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 2002 |
| Grant date | Jul 27, 2004 |
| Priority date | — |
| Expiry date | Aug 22, 2022 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K35/262
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A lead-free solder alloy consisting essentially of, by weight, 3.0% to 3.5% silver, greater than 1% to about 15% copper, the balance tin and incidental impurities, and having an effective melting range of about 215° C. to about 222° C. The solder alloy is noneutectic, and therefore characterized by solidus and liquidus temperatures, the former being in a range of about 215° C. to about 218° C., while the latter is about 290° C. or more. However, the melting mechanism exhibited by the alloy is such that the alloy is substantially all melted and does not exhibit a “mushy zone” above the effective melting range, enabling the alloy to behave similarly to the SnAgCu eutectic alloy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.