Method of forming composite barrier layers with controlled copper interface surface roughness
US7033940B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 2004 |
| Grant date | Apr 25, 2006 |
| Priority date | — |
| Expiry date | Apr 27, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/12044
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A composite α-Ta/graded tantalum nitride/TaN barrier layer is formed in Cu interconnects with a controlled surface roughness for improved adhesion, electromigration resistance and reliability. Embodiments include lining a damascene opening, such as a dual damascene opening in a low-k interlayer dielectric, with an initial layer of TaN, forming a graded tantalum nitride layer on the initial TaN layer and then forming an α-Ta layer on the graded TaN layer, the composite barrier layer having an average surface roughness (Ra) of about 25 Å to about 50 Å. Embodiments further include controlling the surface roughness of the composite barrier layer by varying the N2 flow rate and/or ratio of the thickness of the combined α-Ta and graded tantalum nitride layers to the thickness of the initial TaN layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.