Semiconductor power module
US8125090B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 2010 |
| Grant date | Feb 28, 2012 |
| Priority date | — |
| Expiry date | Jul 27, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2201/10977
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Use of Pb-free solder has become essential due to the environmental problem. A power module is formed by soldering substrates with large areas. It is known that in Sn-3Ag-0.5Cu which hardly creeps and deforms with respect to large deformation followed by warpage of the substrate, life is significantly shortened with respect to the temperature cycle test, and the conventional module structure is in the situation having difficulty in securing high reliability. Thus, the present invention has an object to select compositions from which increase in life can be expected at a low strain rate. In Sn solder, by doping In by 3 to 7% and Ag by 2 to 4.5%, the effect of delaying crack development at a low strain rate is found out, and as a representative composition stable at a high temperature, Sn-3Ag-0.5Cu-5In is selected. Further, for enhancement of reliability, a method for partially coating a solder end portion with a resin is shown.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.