Patent ID: 11961709
Assignee: FEI COMPANY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A charged particle beam device for inspection of a specimen with a plurality of charged particle beamlets, the charged particle beam device comprising:
A specimen holder for holding a specimen;
A source for producing a beam of charged particles;
An illuminator for converting said beam of charged particles into a plurality of charged particle beamlets and directing said plurality of charged particle beamlets onto said specimen, wherein said illuminator comprises:
a multi-aperture lens plate having a plurality of apertures for defining the corresponding plurality of charged particle beamlets; as well as
at least a first electrode for generating an electrical field at a surface of the multi-aperture lens plate; and

A detector for detecting a flux of radiation emanating from the specimen in response to said irradiation by said plurality of charged particle beamlets;
Characterized, in that the aperture plate additionally comprises at least one beamlet shape tuning element provided in between adjacent apertures and arranged for locally modifying said electrical field at said surface of the multi-aperture lens plate, wherein said beamlet shape tuning element comprises a protrusion on said multi-aperture lens plate.