Arc suppressor for electron gun
US5177402A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1992 |
| Grant date | Jan 5, 1993 |
| Priority date | — |
| Expiry date | Jan 3, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/0206
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An arc suppressor is provided for an electron gun of the type used e.g. in semiconductor lithography equipment. The arc suppressor prevents damaging emission properties of the electron gun either due to variation of the cathode work function or any damage to the emitter apex. The arc suppressor includes a resistance and an inductor in series with each electrode lead providing voltage or current to the various electrodes of the electron gun. The inductance is provided by a ferrite toroid which contains a plurality of holes in addition to the main central hole. The leads for each electrode are wrapped around the toroid through the various holes, with one hole being provided for each lead. Thus advantageously each lead is isolated magnetically from the others, reducing the transformer and capacitive effects that couple one lead to another.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.