Abstract: The disclosure relates to a charged particle beam apparatus configured to project charged particle beams towards a sample. The charged particle beam apparatus comprises: a plurality of charged particle-optical columns configured to project respective charged particle beams towards the sample, wherein each charged particle-optical column comprises: a charged particle source configured to emit the charged particle beam towards the sample, the charged particle sources being comprised in a source array; an objective lens comprising an electrostatic electrode configured to direct the charged particle beam towards the sample; and a detector associated with the objective lens array, configured to detect signal charged particles emitted from the sample. The objective lens is the most down-beam element of the charged particle-optical column configured to affect the charged particle beam directed towards the sample.

Abstract: A multi-beam electron-optical system for a charged-particle assessment tool, the system comprising: an objective lens array assembly comprising a plurality of objective lenses, each configured to project one of a plurality of charged-particle beams onto a sample; a detector array associated with the objective lens array assembly and configured to detect charged-particles emitted from the sample; and a circuit comprising an amplifier in data communication with the detector array; wherein the amplifier is configured to be tunable in order to tune amplification of signals from the detector array.

Abstract: Disclosed herein is an inspection tool and a method for identifying defects in a sample. The method includes steps of scanning a first area of a sample with a first detector-beam and scanning a second area of the sample with a second detector-beam, then receiving first and second signals that are derived from the first and second detector-beams. The first and second signals are compared to determine whether a defect is present in the sample.

Abstract: A detector substrate (or detector array) for use in a charged particle multi-beam assessment tool to detect charged particles from a sample. The detector substrate defines an array of apertures for beam paths of respective charged particle beams of a multi-beam. The detector substrate includes a sensor unit array. A sensor unit of the sensor unit array is adjacent to a corresponding aperture of the aperture array. The sensor unit is configured to capture charged particles from the sample. The detector array may include an amplification circuit associated with each sensor unit in the sensor unit array and proximate to the corresponding aperture in the aperture array. The amplification circuit may include a Trans Impedance Amplifier and/or an analogue to digital converter.