Method and apparatus for in-situ plasma cleaning of electron beam optical systems
US4665315A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1985 |
| Grant date | May 12, 1987 |
| Priority date | — |
| Expiry date | Apr 1, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for in-situ cleaning of charged particle beam optical systems such as electron microscopes, electron beam lithography systems, ion beam microscopes or lithography systems, through the use of a specially introduced plasma forming gas such as hydrogen that is excited by applying a high voltage, high frequency excitation potential between various optical elements of the electron beam optical column. Alternately, specially constructed separate plasma forming electrodes can be built into the electron beam optical system for this purpose. During the cleaning operation the plasma reacts chemically with the contaminants previously formed on the surface of the electron beam column optical elements to form gaseous reactants which then are pumped out of the electron beam column system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.