Electron optics for multi-beam electron beam lithography tool
US6617587B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Sep 12, 2002 |
| Grant date | Sep 9, 2003 |
| Priority date | — |
| Expiry date | Sep 12, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/3174
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A charge particle optical column capable of being used in a high throughput, mutli-column, multi-beam electron beam lithography system is disclosed herein. The column has the following properties: purely electrostatic components; small column footprint (20 mm square); multiple, individually focused charge particle beams; telecentric scanning of all beams simultaneously on a wafer for increased depth of field; and conjugate blanking of the charged particle beams for reduced beam blur. An electron gun is disclosed that uses microfabricated field emission sources and a microfabricated aperture-deflector assembly. The aperture-deflector assembly acts as a perfect lens in focusing, steering and blanking a multipicity of electron beams through the back focal plane of an immersion lens located at the bottom of the column. Beam blanking can be performed using a gating signal to decrease beam blur during writing on the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.