Scanning electron microscope
US5387793A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 1993 |
| Grant date | Feb 7, 1995 |
| Priority date | — |
| Expiry date | Oct 12, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/28
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Provided between an optical axis of a primary electron beam directed to a specimen and a secondary electron detector for detecting secondary electrons emitted from the specimen is a shielding electrode which has a transparency for secondary electrons and has a shielding effect for an attracting electric field produced by the secondary electron detector. An opposed electrode is provided at a position facing the shielding electrode with the optical path of the electron beam disposed therebetween. Applied across the shielding electrode and the opposed electrode is a voltage which produces a deflecting electric field along the electron beam path in the vicinity of the secondary electron detector. The deflecting electric field deflects the secondary electrons to the shielding electrode side so that they pass therethrough before they are captured by the secondary electron detector. Optical axis correction coils are provided for generating a magnetic field to correct any bending effect on the trajectory of the primary electron beam by the deflecting electric field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.