Apparatus and method for actively controlling the DC potential of a cathode pedestal
US5737177A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1996 |
| Grant date | Apr 7, 1998 |
| Priority date | — |
| Expiry date | Oct 17, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T279/23
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for actively controlling the DC cathode potential of a wafer support pedestal within a semiconductor wafer processing system. The apparatus contains a variable DC power supply coupled through an RF filter to a cathode pedestal. The variable DC power supply is actively controlled by a control signal generated by a cathode bias control unit, e.g., a computer or other control circuitry. The cathode bias control unit can be as simple as an operator adjustable control signal, e.g., a rheostat. However, for more accurate control of the DC power supply, a feedback circuit is used that generates a control signal that is proportional to the peak-to-peak voltage on a cathode pedestal. The application of the DC bias to the pedestal reduces the DC potential difference between the wafer and the cathode and, thereby avoids arcing from the wafer to the pedestal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.