Method and apparatus for removing particulates from semiconductor substrates in plasma processing chambers
US5779807A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1996 |
| Grant date | Jul 14, 1998 |
| Priority date | — |
| Expiry date | Oct 29, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/022
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An electrostatic technique for removing particulate matter from a semiconductor wafer in a plasma processing chamber, such as a plasma-enhanced chemical vapor deposition (PECVD) chamber. During a particulate removal phase of operation, a normally grounded electrode that supports the wafer is temporarily isolated from ground and a bias voltage generator is simultaneously connected to the electrode, supplying sufficient bias voltage to electrostatically launch particulates from the surface of the wafer. A plasma formed above the normally grounded electrode is maintained during the particulate removal phase, and particulates launched from the wafer become suspended in a sheath region surrounding the plasma, from where they can be later removed by a purging flow of gas. Preferably, the bias voltage generator provides a bias voltage that alternates in polarity, to ensure removal of both positively-charged and negatively charged particles from the wafer surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.