Lead-free solder used for connecting electronic parts on organic substrate and electronic products made using same
US5942185A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1997 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | Oct 28, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S228/903
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Provided is a lead-free solder for connecting LSI and parts on organic substrates, which can provide soldering at a maximum temperature of 220.degree.-230.degree. C. and which has a sufficient reliability in mechanical strength even at a high temperature of 150.degree. C. Also provided are electronic products prepared using this lead-free solder. The lead-free solder has a solder composition including 3-5% Zn and 10-23% Bi, the balance being Sn. Preferably, the solder composition is a composition (Sn, Zn, Bi) surrounded by lines connecting A and B, B and C and C and A, where A is (85, 5, 10 ), B is (72, 5, 23) and C is (76, 3, 21), of a ternary diagram having pure Sn, pure Zn and pure Bi at the vertices of an equilateral triangle. Through use of this solder, it is possible to solder parts, etc. on conventionally employed organic substrates at reflow temperatures equivalent to those for conventional Pb--Sn eutectic solders. The solder does not damage the environment, can be stably supplied and is low in cost.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.