Method to reduce Rs pattern dependence effect
US7208404B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 2003 |
| Grant date | Apr 24, 2007 |
| Priority date | — |
| Expiry date | Jan 11, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/7684
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming a copper interconnect in an opening within a pattern is described. The copper interconnect has an Rs that is nearly independent of opening width and pattern density. A first copper layer having a concave upper surface and thickness t1 is formed in a via or trench in a dielectric layer by depositing copper and performing a first CMP step. A second copper layer with a thickness t2 where t2≦t1 and having a convex lower surface is deposited on the first copper layer by a selective electroplating method. The first and second copper layers are annealed and then a second CMP step planarizes the second copper layer to become coplanar with the dielectric layer. The invention is also a copper interconnect comprised of the aforementioned copper layers where the first copper layer has a grain density (GD1)≧GD2 for the second copper layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.