Method of illuminating an object with a focused electron beam and an electron-optical illuminating system therefor
US5483073A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 22, 1993 |
| Grant date | Jan 9, 1996 |
| Priority date | — |
| Expiry date | Dec 22, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention is directed to a method for illuminating an object with a focused electron beam as well as to an electron-optical illuminating apparatus therefor. The crossover of an electron source is imaged, greatly demagnified, into the object plane via four imaging stages. The two first condenser stages define a zoom system. The cross section of the crossover image in the input image plane of the third condenser stage can be varied by varying the corresponding lens excitation. The third condenser stage images the crossover image from the input image plane into the input image plane of the objective. A multiple diaphragm is mounted between the third condenser stage and the input image plane of the objective. This multiple diaphragm has several apertures which are, in part, off-axis. The electron beam can be deflected by magnetic deflecting systems in such a manner that only the electron beam, which is transmitted through one diaphragm aperture of the multiple diaphragm, contributes an amount to the illumination of the object. In this way, the aperture of the illuminating beam component can be varied independently of the imaging scale with which the crossover is imaged on the objec…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.