Apparatus for coating or etching by means of a plasma
US4863549A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 1, 1988 |
| Grant date | Sep 5, 1989 |
| Priority date | — |
| Expiry date | Jul 1, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/3348
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention concerns apparatus for coating or etching by means of a plasma. Herein a first electrode (5) is connected to a high frequency voltage which produces plasma from a gas. A second electrode (6), on which the substrate (7) to be coated or etched is disposed, is connected to a medium frequency voltage which accelerates the ions of the plasma to the substrate (7). According to the invention, this medium frequency voltage consists of unipolar pulses that have the same amplitude for a predeterminable time interval. The number of ions impinging on the substrate (7) is thereby decoupled from the amplitude of the applied medium frequency voltage. It is determined solely by the frequency or width of these pulses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.