Detector optics for charged particle beam inspection system
US7122795B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 27, 2004 |
| Grant date | Oct 17, 2006 |
| Priority date | — |
| Expiry date | Apr 27, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/244
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A charged particle beam column for substrate inspection includes detector optics with high secondary electron detection efficiency combined with minimal distortion of the charged particle beam. One embodiment of the detector optics includes a symmetrizing electrode configured with a secondary electron detector to produce a generally cylindrically symmetric electric field about the optical axis of the column. Control electrodes may be used for screening the charged particle beam from the secondary electron detector and for controlling the electric field at the surface of the substrate. In some embodiments, the control electrodes are cylindrically symmetric about the optical axis; whereas in other embodiments, the cylindrical symmetry of one or more control electrodes is broken in order to improve the secondary electron detection efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.