Krypton sputtering of thin tungsten layer for integrated circuits
US7790604B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 2007 |
| Grant date | Sep 7, 2010 |
| Priority date | — |
| Expiry date | Jun 15, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/664
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of depositing a bilayer of tungsten over tungsten nitride by a plasma sputtering process in which krypton is used as the sputter working gas during the tungsten deposition. Argon may be used as the sputtering working gas during the reactive sputtering deposition of tungsten nitride. The beneficial effect of reduction of tungsten resistivity is increased when the thickness of the tungsten layer is less than 50 nm and further increased when less than 35 nm. The method may be used in forming a gate stack including a polysilicon layer over a gate oxide layer over a silicon gate region of a MOS transistor in which the tungsten nitride acts as a barrier. A plasma sputter chamber in which the invention may be practiced includes gas sources of krypton, argon, and nitrogen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.