Immersion lens with magnetic shield for charged particle beam system
US6768117B1 · kind B1 · utility
2Cited by
7References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 25, 2000 |
| Grant date | Jul 27, 2004 |
| Priority date | — |
| Expiry date | Jun 29, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/3175
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An immersion lens for a charged particle beam lithography system includes a magnetically floating shield that limits a deflection magnetic field from creating eddy currents in electrically conductive components of the system downstream from the shield. The surface of the shield lies parallel or approximately parallel to a magnetic equipotential surface of the focusing magnetic field so that the shield does not affect the focusing magnetic field. The shield is, e.g., a ferrite disk or a hollow ferrite cone defining a central bore for passage of the charged particle beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.