A secondary charged particle imaging system for imaging a secondary charged particle beam emanating from a sample by impingement of a primary charged particle beam is provided. The system includes a detector arrangement, and an adaptive secondary charged particle optics. The detector arrangement comprises a first detection element for detecting a first secondary charged particle sub-beam of the secondary charged particle beam, and a second detection element for detecting a second secondary charged particle sub-beam of the secondary charged particle beam. The adaptive secondary charged particle optics comprises an aperture plate including a first opening for letting the first secondary charged particle sub-beam pass through and a second opening for letting the second secondary charged particle sub-beam pass through; a lens system for mapping the secondary charged particle beam onto the aperture plate, the lens system comprising a first lens and a second lens; and a controller for controlling the excitation of the first lens and the excitation of the second lens. The controller is configured to independently control the excitation of the first lens and of the second lens to map the secondary charged particle beam onto the aperture plate so that the first secondary charged particle sub-beam passes through the first opening and the second secondary charged particle sub-beam passes through the second opening independent of a variation of at least one first operating parameter selected from a group comprising: landing energy of the primary charged particle beam on the sample, extraction field strength for the secondary charged particle beam at the sample, magnetic field strength of an objective lens that focuses the primary charged particle beam onto the sample, and working distance of the objective lens from the sample.

Particle beam system comprising a particle source; a first multi-aperture plate with a multiplicity of openings downstream of which particle beams are formed; a second multi-aperture plate with a multiplicity of openings which are penetrated by the particle beams; an aperture plate with an opening which is penetrated by all the particles which also penetrate the openings in the first and the second multi-aperture plate; a third multi-aperture plate with a multiplicity of openings which are penetrated by the particle beams, and with a multiplicity of field generators which respectively provide a dipole field or quadrupole field for a beam; and a controller for feeding electric potentials to the multi-aperture plates and the aperture plate so that the second openings in the second multi-aperture plate respectively act as a lens on the particle beams and feed adjustable excitations to the field generators.

A method of imaging a secondary charged particle beam emanating from a sample by impingement of a primary charged particle beam is provided. The method includes setting a first operating parameter to a first value. The first operating parameter is selected from a group including: landing energy of the primary charged particle beam on the sample, extraction field strength for the secondary charged particle beam at the sample, magnetic field strength of an objective lens that focuses the primary charged particle beam onto the sample, and working distance of the objective lens from the sample. The method further includes controlling, while the first operating parameter is set to the first value, the excitation of a first lens and of a second lens to map the secondary charged particle beam onto a first region on an aperture plate. The first region overlaps with a first opening of the aperture plate and with a second opening of the aperture plate. The method further includes setting the first operating parameter to a second value different from the first value. The method further includes controlling, while the first operating parameter is set to the second value, the excitation of the first lens and of the second lens to map the secondary charged particle beam onto the first region on the aperture plate.

The present disclosure relates to an apparatus and method that manipulate the voltage at an edge ring relative to a substrate located on a substrate support assembly. The substrate support assembly has a body having a substrate support portion having a substrate electrode embedded therein for applying a substrate voltage to a substrate. The body of the substrate support assembly further has an edge ring portion disposed adjacent to the substrate support portion. The edge ring portion has an edge ring electrode embedded therein for applying an edge ring voltage to an edge ring. An edge ring voltage control circuit is coupled to the edge ring electrode. A substrate voltage control circuit is coupled to the substrate electrode. The edge ring voltage control circuit and the substrate voltage control circuit are independently tunable to generate a difference in voltage between the edge ring voltage and the substrate voltage.

A multi-beam generator for a charged-particle multi-beam system comprises: a stack of multi-aperture plates with at least a first multi-lens array for long range focal length variation; and a second multi-lens array for short range focal length variation. Aperture diameters of the first multi-lens array vary to encode a pre-compensation of a spherically curved image field in an object plane of the multi-beam system. Aperture diameters of the second multi-lens array vary to encode a pre-compensation of a residual image field error in the object plane which is not pre-compensated by the first multi-lens array. The control unit of the multi-beam generator provides driving voltages to the first and second lens arrays based on the current working point of the charged-particle multi-beam system.