Lead-free solder connection structure and solder ball
US8975757B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 2009 |
| Grant date | Mar 10, 2015 |
| Priority date | — |
| Expiry date | Sep 23, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/3511
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Solder used for flip chip bonding inside a semiconductor package was a Sn—Pb solder such as a Pb-5Sn composition. Lead-free solders which have been studied are hard and easily form intermetallic compounds with Sn, so they were not suitable for a flip chip connection structure inside a semiconductor package, which requires stress relaxation properties. This problem is eliminated by a flip chip connection structure inside a semiconductor package using a lead-free solder which is characterized by consisting essentially of 0.01-0.5 mass percent of Ni and a remainder of Sn. 0.3-0.9 mass percent of Cu and 0.001-0.01 mass percent of P may be added to this solder composition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.