Electron density measurement and control system using plasma-induced changes in the frequency of a microwave oscillator
US6573731B1 · kind B1 · utility
10Cited by
28References
34Claims
0Family size
Assignee
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Key dates
| Filing date | Apr 9, 2002 |
| Grant date | Jun 3, 2003 |
| Priority date | — |
| Expiry date | Apr 9, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/3299
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and system for measuring at least one of a plasma density and an electron density (e.g., in a range of 1010 to 1012 electrons/cm−3) using plasma induced changes in the frequency of a microwave oscillator. Measurement of at least one of the plasma density and the electron density enables plasma-assisted processes, such as depositions or etches, to be controlled using a feedback control. Both the measurement method and system generate a control voltage that in turn controls a plasma generator to maintain at least one of the plasma density and the electron density at a pre-selected value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.