Lead-free low-temperature solder
US8303735B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 18, 2006 |
| Grant date | Nov 6, 2012 |
| Priority date | — |
| Expiry date | Dec 5, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K3/3463
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A conventional low-temperature solder containing Pb or Cd had problems with respect to environmental pollution. A conventional low-temperature lead-free solder had a liquidus temperature which was too high for low heat resistance parts having a heat resistance temperature of 130° C., or it was brittle or had low mechanical strength. A lead-free low-temperature solder according to the present invention comprises 48-52.5 mass % of In and a balance of Bi, and most of the structure is constituted by a BiIn2 intermetallic compound which is not brittle. Zn or La can be added in order to further improve solderability, and a small amount of P can be added to prevent corrosion at high temperatures and high humidities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.