Magnification compensation apparatus
US4999496A · kind A · utility
22Cited by
15References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1989 |
| Grant date | Mar 12, 1991 |
| Priority date | — |
| Expiry date | Dec 13, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/21
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention relates to an apparatus for generating a magnification compensation signal for use in a scanning electron microscope. The apparatus includes an electron beam generator that generates a beam at a predetermined energy level in accordance with a beam energy signal. The apparatus allows for refocussing by varying the beam energy signal about a nominal value corresponding to the predetermined energy level. The apparatus also provides a magnification compensator producing a magnification compensation signal that varies in accordance with the variation of the beam energy signal from the predetermined energy level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.