Fei Comapny

Lubomír Tůma

Petr Hlavenka

Petr Sytar

Bohuslav Sed'a

Radek Ceska

A charged particle beam system can include a vacuum chamber, a specimen holder for holding a specimen within the vacuum chamber, and a charged particle column. The charged particle column can include a charged particle source for producing a beam of charged particles along an optical axis and a magnetic immersion lens for focusing the beam of charged particles. The magnetic immersion lens can include a first lens pole disposed adjacent a first surface of the specimen, an excitation coil surrounding the first lens pole, and a counterpole disposed adjacent a second surface of the specimen, the counterpole including one or more magnets disposed on the counterpole.

Counter pole with permanent magnets

The invention relates to a compound objective lens for a Scanning Electron Microscope having a conventional magnetic lens excited by a first lens coil, an immersion magnetic lens excited by a second lens coil, and an immersion electrostatic lens excited by the voltage difference between the sample and the electrostatic lens electrode. For a predetermined excitation of the lens, the electron beam can be focused on the sample using combinations of excitations of the two lens coils. More BSE information can be obtained when the detector distinguishes between BSE's () that strike the detector close to the axis and BSE's () that strike the detector further removed from the axis. By tuning the ratio of the excitation of the two lens coils, the distance from the axis that the BSE's impinge on the detector can be changed, and the compound lens can be used as an energy selective detector.

Method of using a compound particle-optical lens

The invention relates to an in-column back-scattered electron detector, the detector placed in a combined electrostatic/magnetic objective lens for a SEM. The detector is formed as a charged particle sensitive surface, preferably a scintillator disk that acts as one of the electrode faces forming the electrostatic focusing field. The photons generated in the scintillator are detected by a photon detector, such as a photo-diode or a multi-pixel photon detector. The objective lens may be equipped with another electron detector for detecting secondary electrons that are kept closer to the axis. A light guide may be used to offer electrical insulation between the photon detector and the scintillator.

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Brno, Czechia

Lubomír Tůma