Barrier layers for electroplated SnPb eutectic solder joints
US5937320A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 1998 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Apr 8, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/3651
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present invention provides a means of fabricating a reliable C4 flip-chip structure for low-temperature joining. The electrochemically fabricated C4 interconnection has a barrier layer between the electroplated tin-rich solder bump and the ball-limiting metallurgy that protects the terminal metal in the ball-limiting metallurgy from attack by the Sn in the solder. The barrier layer is electroplated through the same photoresist mask as the solder and thus does not require a separate patterning step. A thin layer of electroplated nickel serves as a reliable barrier layer between a copper-based ball-limiting metallurgy and a tin-lead (Sn--Pb) eutectic C4 ball.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.