Method for improving conformity and contact bottom coverage of sputtered titanium nitride barrier layers
US5833817A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1996 |
| Grant date | Nov 10, 1998 |
| Priority date | — |
| Expiry date | Apr 22, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76865
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method is described for overcoming the non-conformity and poor step coverage incurred when materials such as metals and barrier layers are deposited into contact openings by physical-vapor-deposition(PVD) techniques such as sputtering and evaporation. Conventional PVD deposition into a vertical walled opening results in a deposit whose thickness diminishes towards the base of the opening. This causes voids when the opening is subsequently filled by chemical-vapor-deposited(CVD) tungsten as well as potential failure of the barrier material due to inadequate coverage at the base of the opening. The method utilizes a two stage reactive ion etching technique to selectively etch the upper portion of the deposited layer while protecting the lower portion with photoresist. A second deposition of barrier layer material then restores material at the top of the opening while augmenting the thickness at the base. This reduces the negative taper of the opening and allows total filling by the subsequent CVD deposition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.