Plasma generating apparatus
US5147493A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jun 12, 1991 |
| Grant date | Sep 15, 1992 |
| Priority date | — |
| Expiry date | Jun 12, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/3348
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A plasma generating apparatus comprising a transformer including a primary winding connected to a high frequency power source and a secondary winding having two end terminals and a plurality of tap terminals connected between the end terminals, the transformer being adapted to deliver first and second high frequency electric powers with a phase difference of 180.degree. from the end terminals, upper and lower electrodes disposed in a vacuum chamber so as to be opposed at a distance from each other and supplied with the first and second high frequency powers, respectively, and a power ratio selector for switching the tap terminals to select the ratio between the first and second high frequency powers supplied to the electrodes, wherein a to-be-processed object placed on the lower electrode is processed by means of plasma formed between the electrodes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.