Structure of UBM and solder bumps and methods of fabrication
US8003512B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2009 |
| Grant date | Aug 23, 2011 |
| Priority date | — |
| Expiry date | Mar 12, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/15788
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Methods and UBM structures having bilayer or trilayer UBM layers that include a thin TiW adhesion layer and a thick Ni-based barrier layer thereover both deposited under sputtering operating conditions that provide the resultant bilayer or trilayer UBM layers with minimal composite stresses. The Ni-based barrier layer may be pure Ni or a Ni alloy. These UBM layers may be patterned to fabricate bilayer or trilayer UBM capture pads, followed by joining a lead-free solder thereto for providing lead-free solder joints that maintain reliability after multiple reflows. Optionally, the top layer of the trilayer UBM structures may include soluble or insoluble metals for doping the lead-free solder connections.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.