Method and apparatus for detecting endpoint in a dry etching system by monitoring a superimposed DC current
US7754615B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Jul 31, 2006 |
| Grant date | Jul 13, 2010 |
| Priority date | — |
| Expiry date | Feb 7, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for detecting the endpoint in a dry plasma etching system comprising a first electrode (e.g., upper electrode) and a second electrode (e.g., lower electrode) upon which a substrate rests is described. A direct current (DC) voltage is applied between the first electrode and a ring electrode surrounding the second electrode, and the DC current is monitored to determine the endpoint of the etching process. The DC current is affected by the impedance of the plasma, and therefore responds to many variations including, for example, the plasma density, electron/ion flux to exposed surfaces, the electron temperature, etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.