Ni plating of a BLM edge for Pb-free C4 undercut control
US8476762B2 · kind B2 · utility
7Cited by
10References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 4, 2012 |
| Grant date | Jul 2, 2013 |
| Priority date | — |
| Expiry date | May 4, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/12044
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A structure and a method of manufacturing a Pb-free Controlled Collapse Chip Connection (C4) with a Ball Limiting Metallurgy (BLM) structure for semiconductor chip packaging that reduce chip-level cracking during the Back End of Line (BEOL) processes of chip-join cool-down. An edge of the BLM structure that is subject to tensile stress during chip-join cool down is protected from undercut of a metal seed layer, caused by wet etch of the chip to remove metal layers from the chip's surface and solder reflow, by an electroplated barrier layer, which covers a corresponding edge of the metal seed layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.