Method for igniting low pressure inductively coupled plasma
US5639519A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1995 |
| Grant date | Jun 17, 1997 |
| Priority date | — |
| Expiry date | Nov 20, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/32082
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus for producing a plasma suitable for semiconductor processing at pressures in the low millitorr range. The apparatus includes a vacuum chamber with a dielectric window, a generally planar coil disposed adjacent the window outside the chamber and coupled to an appropriate power source, and a plasma initiator disposed within the chamber. Once the plasma is initiated, the planar coil sustains the plasma by inductive power coupling. In one embodiment the plasma initiator is a secondary electrode disposed within the chamber and coupled to a second RF power source. In an alternative embodiment both the secondary electrode and a target pedestal are coupled to the secondary RF power source through a power splitter. In an alternative embodiment, the plasma initiator is used to ionize a portion of the process gas and provide a plasma that may then inductively couple with the planar coil. Initial ionization of the process gas may be achieved by use of an ultraviolet light source, an ultraviolet laser, a high voltage power source such as a tesla coil, or an electrical arc forming device such as a spark plug.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.