Method for improving uniformity of high-frequency plasma discharge by means of frequency modulation
US8704445B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 2012 |
| Grant date | Apr 22, 2014 |
| Priority date | — |
| Expiry date | Jun 28, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/32155
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method for improving the uniformity of high-frequency discharge plasma by means of frequency modulation is disclosed. In a plasma discharge chamber, there is a pair of parallel electrodes. A high-frequency power supply is adopted to feed the electrodes. The frequency range of the electromagnetic field is 13.56 MHz˜160 MHz. Discharge gas is input to form plasma. The frequency of the fed-in high-frequency electromagnetic field is under automatic tuning control, and keeps changing cyclically without stop in the course of plasma discharge. The range of the frequency change may fall into either a portion of or the entire range of 13.56 MHz˜160 MHz and makes the locations with higher plasma density on the plane in parallel with the electrodes and in the plasma discharge space changed cyclically. In a time slot longer than one frequency change cycle, the average plasma density between the parallel electrodes is uniform.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.