Dual detector optics for simultaneous collection of secondary and backscattered electrons
US7227142B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 28, 2005 |
| Grant date | Jun 5, 2007 |
| Priority date | — |
| Expiry date | Mar 28, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/2448
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A detector optics system for an electron probe system is disclosed. Aspects of the detector optics system include: the ability to simultaneously detect two electron populations, secondary electrons (SEs) and backscattered electrons (BSEs), wherein both populations are emitted from a substrate due to the impact of the electron probe. The design of the detector optics utilizes a field-free tunnel and substrate electric-field control electrodes to enable separation of the SEs and BSEs into two detectors, allowing simultaneous acquisition of topographic and elemental composition data, with minimal impact on the electron probe. The secondary electron signal is a monotonically-varying function of the voltage on the substrate surface. The ratio of the SE signal to the BSE signal gives a testing signal which is independent of the primary beam current and serves as an absolute voltage probe of surface voltages without the need for an external reference voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.