Electron lens and charged particle beam apparatus
US7759652B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 2007 |
| Grant date | Jul 20, 2010 |
| Priority date | — |
| Expiry date | Jun 16, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31749
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides a compact electron lens causing little aberration, and a charged particle beam apparatus such as a scanning electron microscope that is super compact and offers a high resolution. An upper magnetic pole and a sample-side magnetic pole are magnetically coupled to the respective poles of a permanent magnet that is made of a highly strong magnetic material such as a rare-earth cobalt system or a neodymium-iron-boron system, that is axially symmetrical, and that has a hole in the center thereof. An inner gap is created on the side of a center axis. Thus, a magnetic lens is formed axially. Moreover, a semi-stationary magnetic path that shields an outside magnetic field and has the magnetic reluctance thereof regulated is disposed outside. The sample-side magnetic pole and magnetic path defines a region where magnetic reluctance is the highest outside the permanent magnet. A space defined by the permanent magnet, upper magnetic pole, sample-die magnetic pole, and semi-stationary magnetic path is filled with a filling made of a non-magnetic material. Thus, an objective lens is constructed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.