Methods for post polysilicon etch photoresist and polymer removal with minimal gate oxide loss
US6955177B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2001 |
| Grant date | Oct 18, 2005 |
| Priority date | — |
| Expiry date | Sep 6, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/335
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present invention pertains to methods for cleaning semiconductor wafers, more specifically, for removing polymeric and other residues from a wafer using dry plasmas generated with microwave (MW), electromagnetic field (inductively-coupled plasma (ICP)), and radio frequency (RF) energy. First, a wafer is treated by applying a microwave-generated plasma or an inductively-coupled plasma. Second, a radio frequency generated plasma is applied. Each of the microwave-generated plasma and the inductively-coupled plasma is produced from a gas mixture, which includes an oxygen source gas, a fluorine source gas, and a hydrogen source gas. Using such plasmas provides more controllable etch rates than conventional plasmas via control of fluorine concentration in the plasma. Application of a radio frequency generated (preferably oxygen-based) plasma is used for additional photoresist and polymer removal. The use of this two-step approach provides superior wafer cleaning compared to conventional wet and dry clean methods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.