Semiconductor device and method of forming multi-layered UBM with intermediate insulating buffer layer to reduce stress for semiconductor wafer
US8642469B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 2011 |
| Grant date | Feb 4, 2014 |
| Priority date | — |
| Expiry date | Jun 9, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/181
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor wafer has a contact pad. A first insulating layer is formed over the wafer. A second insulating layer is formed over the first insulating layer and contact pad. A portion of the second insulating layer is removed to expose the contact pad. A first UBM layer is formed over and follows a contour of the second insulating layer and contact pad to create a well over the contact pad. A first buffer layer is formed in the well over the first UBM layer and the contact pad. A second UBM layer is formed over the first UBM layer and first buffer layer. A third UBM layer is formed over the second UBM layer. A bump is formed over the third UBM layer. The first buffer layer reduces stress on the bump and contact pad. A second buffer layer can be formed between the second and third UBM layers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.