Automatic impedance matching apparatus and method
US5195045A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 1991 |
| Grant date | Mar 16, 1993 |
| Priority date | — |
| Expiry date | Feb 27, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H7/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An automatic impedance matching apparatus for matching an RF-signal generator to a load, such as a plasma etching chamber, is disclosed. The matching apparatus comprises a matching network having two variable impedance devices, a tune detector for detecting the condition of the impedance match between the RF-signal and the load, and a controller for modifying the values of the variable impedance components in response to the measured tune condition. The present invention disclosed improve reset and convergence unit and eliminates the need for the "dead-band" provided around the matching point found in prior art impedance matching controllers. Also disclosed is an improved adjustment unit for adjusting the variable impedance components which is faster and more stable than found in prior art controllers. Also disclosed is a normalization unit for normalizing the input detection siganls such that variations in turning performance due to variations in input power level from the source are substantially reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.