Lead-free solder
US6231691A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1997 |
| Grant date | May 15, 2001 |
| Priority date | — |
| Expiry date | Feb 10, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K35/262
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A Sn--Ag--Cu eutectic alloy is modified with one or more low level and low cost alloy additions to enhance high temperature microstructural stability and thermal-mechanical fatigue strength without decreasing solderability. Purposeful fourth or fifth element additions in the collective amount not exceeding about 1 weight % (wt. %) are added to Sn--Ag--Cu eutectic solder alloy based on the ternary eutectic Sn--4.7%Ag--1.7%Cu (wt. %) and are selected from the group consisting essentially of Ni, Fe, and like-acting elements as modifiers of the intermetallic interface between the solder and substrate to improve high temperature solder joint microstructural stability and solder joint thermal-mechanical fatigue strength.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.