Plasma composition for selective high-k etch
US7598184B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 2006 |
| Grant date | Oct 6, 2009 |
| Priority date | — |
| Expiry date | Jan 25, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/60
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for the selective removal of a high-k layer such as HfO2 over silicon or silicon dioxide is provided. More specifically, a method for etching high-k selectively over silicon and silicon dioxide and a plasma composition for performing the selective etch process is provided. Using a BCl3 plasma with well defined concentrations of nitrogen makes it possible to etch high-k with at a reasonable etch rate while silicon and silicon dioxide have an etch rate of almost zero. The BCl3 comprising plasmas have preferred additions of 10 up to 13% nitrogen. Adding a well defined concentration of nitrogen to the BCl3/N2 plasma gives the unexpected deposition of a Boron-Nitrogen (BxNy) comprising film onto the silicon and silicon dioxide which is not deposited onto the high-k material. Due to the deposition of the Boron-Nitrogen (BxNy) comprising film, the etch rate of silicon and silicon dioxide is dropped down to zero. The Boron-Nitrogen (BxNy) comprising film can be removed during the etching process using the right substrate bias (leading to ion bombardment) or after the etching process by a simple water rinse since the Boron-Nitrogen (BxNy) comprising film is water soluble.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.