Residue-free solder paste
US6887319B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 2003 |
| Grant date | May 3, 2005 |
| Priority date | — |
| Expiry date | Apr 15, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K3/3485
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A residue-free solder paste which leaves little or no flux residue after reflow soldering and which have good printability, storage stability, retainability of parts, and wettability, comprises a solder powder mixed with a rosin-free pasty flux. The flux comprises at least one solid solvent and at least one highly viscous solvent in a total amount of 30-90 mass %, in addition to at least one liquid solvent, all the solvents vaporizing at a reflow soldering temperature. The flux may further contain 0.5-12% of a thixotropic agent such as a fatty acid amide and 1-15% of an activator selected from organic acids and their amine salts, the thixotropic agent and activator vaporizing in the presence of the solvents while the solvents are vaporizing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.