Deposition of tungsten
US5407698A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 30, 1992 |
| Grant date | Apr 18, 1995 |
| Priority date | — |
| Expiry date | Apr 30, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76877
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method is provided for low pressure chemical deposition of tungsten and tungsten metallization for defining interconnects for an integrated circuit. A surface layer of tungsten is provided which has a low film stress and a smooth surface characterized by a low diffuse reflectivity and high specular reflectivity, to facilitate photo-lithography. Tungsten is deposited by reduction of WF.sub.6 with H.sub.2 and SiH.sub.4 in nitrogen. Control of the gas flow rates, pressure, temperature and H.sub.2 /WF.sub.6 ratio in the reactive gas mixture provides for tailoring of the structure and characteristics of a deposited tungsten layer to provide high step coverage or a smooth surface for forming an overlying layer of tungsten which may be patterned photo-lithographically for defining interconnect. In order to provide metallization providing both good step coverage in via and contact holes and smooth surface for deposition of surface metallization, a two-stage tungsten deposition is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.