Illumination system for electron beam lithography tool
US6333508A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | May 30, 2000 |
| Grant date | Dec 25, 2001 |
| Priority date | — |
| Expiry date | May 30, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31774
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for controlling beam emittance by placing a quadrupole lens array in a drift space of an illumination system component. The illumination system component may be an electron gun or a liner tube or drift tube, attachable to an electron gun. The quadrupole lens array may be three or more mesh grids or a combination of grids and continuous foils. The quadrupole lens array forms a multitude of microlenses resembling an optical "fly's eye" lens. The quadrupole lens array splits an incoming solid electron beam into a multitude of subbeams, such that the outgoing beam emittance is different from the incoming beam emittance, while beam total current remains unchanged. The method and apparatus permit independent control of beam current and beam emittance, which is beneficial in a SCALPEL illumination system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.