Refractory metal capped low resistivity metal conductor lines and vias formed using PVD and CVD
US6323554A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1998 |
| Grant date | Nov 27, 2001 |
| Priority date | — |
| Expiry date | Jul 10, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/959
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Capping a low resistivity metal conductor line or via with a refractory metal allows for effectively using chemical-mechanical polishing techniques because the hard, reduced wear, properties of the refractory metal do not scratch, corrode, or smear during chemical-mechanical polishing. Conductive lines and vias are created using a combination of both physical vapor deposition (e.g., evaporation or collimated sputtering) of a low resistivity metal or alloy followed by chemical vapor deposition (CVD) of a refractory metal and subsequent planarization. Altering a ratio of SiH.sub.4 to WF.sub.6 during application of the refractory metal cap by CVD allows for controlled incorporation of silicon into the tungsten capping layer. Collimated sputtering allows for creating a refractory metal liner in an opening in a dielectric which is suitable as a diffusion barrier to copper based metalizations as well as CVD tungsten. Ideally, for faster diffusing metals like copper, liners are created by a two step collimated sputtering process wherein a first layer is deposited under relatively low vacuum pressure where directional deposition dominates (e.g., below 1 mTorr) and a second layer is deposit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.