Electrostatic lens having a dielectric semiconducting membrane
US9934934B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 26, 2014 |
| Grant date | Apr 3, 2018 |
| Priority date | — |
| Expiry date | May 26, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/21
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Electrostatic lenses for focusing a beam of charged particles, and in particular an electron beam, are used especially in the electron guns of electron microscopes or electron-beam lithography apparatuses. The present disclosure improves the possibilities for focusing the particle beam, in particular an electron beam emitted by a cathode. The lens comprises at least one conducting electrode having at least one through-opening for the passage of an electron beam. Different electric fields are set up upstream and downstream of the opening. The passage opening is at least partially closed by a planar or curved thin membrane of semi-conducting material that is transparent to electrons and has a high dielectric permittivity. Structuring the membrane (holes or thickened portions of electrodes deposited on the membrane) makes it possible to correct lens aberration defects.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.