Angular aperture shaped beam system and method
US6977386B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 2003 |
| Grant date | Dec 20, 2005 |
| Priority date | — |
| Expiry date | Dec 1, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31755
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides improved angular aperture schemes for generating shaped beam spots having a desired geometric shape from rectangular, elliptical, and semi-elliptical apertures having one sharp edge. A sharper beam edge can be generated by offsetting the rectangular or elliptical aperture in combination with under or over focus. In the spherical aberration limit, under-focused semi-circle apertures provide a sharp, flat edge. The sharp edge can be made resolute enough for precision milling applications, and at the same time, the spot can be made large enough with enough overall current and current density to efficiently mill away material in either a production or laboratory environment. Depending on the particular beam spot that is desired, combinations of techniques including defocusing, aperture offsetting, and stigmation adjustment, can be used in both spherical aberration dominant and chromatic aberration dominant environments to achieve a desired beam for a desired application.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.