Selective thin metal cap process
US7514361B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 2007 |
| Grant date | Apr 7, 2009 |
| Priority date | — |
| Expiry date | Aug 20, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76825
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of creating metal caps on copper lines within an inter-line dielectric (ILD) deposits a thin (e.g., 5 nm) metal blanket film (e.g., Ta/TaN) on top the copper lines and dielectric, after the wafer has been planarized. Further a thin dielectric cap is formed over the metal blanket film. A photoresist coating is deposited over the thin dielectric cap and a lithographic exposure process is performed, but without a lithographic mask. A mask is not needed in this situation, because due to the reflectivity difference between copper and the ILD lying under the two thin layers, a mask pattern is automatically formed for etching away the Ta/TaN metal cap between copper lines. Thus, this mask pattern is self-aligned above the copper lines.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.