A method for operating a multi-beam particle beam microscope includes: scanning a multiplicity of particle beams over an object; directing electron beams emanating from impingement locations of the particle beams at the object onto an electron converter; detecting first signals generated by impinging electrons in the electron converter via a plurality of detection elements of a first detection system during a first time period; detecting second signals generated by impinging electrons in the electron converter via a plurality of detection elements of a second detection system during a second time period; and assigning to the impingement locations the signals which were detected via the detection elements of the first detection system during the first time period, for example on the basis of the detection signals which were detected via the detection elements of the second detection system during the second time period.

A detector includes a plurality of sensing elements, section circuitry that communicatively couples a first set of sensing elements to an input of first signal processing circuitry, and a switch network that connects sets of sensing elements. Inter-element switches may connect adjacent sensing elements, including those in a diagonal direction. An output bus may be connected to each sensing element of the first set by a switching element. There may be a common output (pickup point) arranged at one sensing element that is configured to output signals from the first set. Various switching and wiring schemes are proposed. For example, the common output may be directly connected to the switch network. A switch may be provided between the output bus and first signal processing circuitry. A switch may be provided between the switch network and the first signal processing circuitry.

An improved method and apparatus for enhancing an inspection image in a charged-particle beam inspection system. An improved method for enhancing an inspection image comprises acquiring a first image and a second image of multiple stacked layers of a sample that are taken with a first focal point and a second focal point, respectively, associating a first segment of the first image with a first layer among the multiple stacked layers and associating a second segment of the second image with a second layer among the multiple stacked layers, updating the first segment based on a first reference image corresponding to the first layer and updating the second segment based on a second reference image corresponding to the second layer, and combining the updated first segment and the updated second segment to generate a combined image including the first layer and the second layer.

A particle beam system includes: a multi-beam particle source configured to generate a multiplicity of particle beams; an imaging optical unit configured to image an object plane in particle-optical fashion into an image plane and direct the multiplicity of particle beams on the image plane; and a field generating arrangement configured to generate electric and/or magnetic deflection fields of adjustable strength in regions close to the object plane. The particle beams are deflected in operation by the deflection fields through deflection angles that depend on the strength of the deflection fields.

An improved system is disclosed for wafer outer portion inspection in a charged particle beam system, such as a scanning electron microscope (SEM). The system uses multiple conductive rings around the wafer to correct an e-field distortion occurring at the wafer outer portion. The rings are applied with different complimentary voltages in order achieve a precise compensation of the e-field distortion.

A scanning electron microscopy system that includes a primary electron beam radiation unit configured to irradiate a first pattern of a substrate having a second pattern formed in a peripheral region of the first pattern, a detection unit configured to detect back scattered electrons emitted from the substrate, an image generation unit configured to generate an electron beam image corresponding to a strength of the back scattered electrons, a designating unit configured to designate a depth measurement region in which the first pattern exists on the electron beam image, and a processing unit configured to obtain an image signal of the depth measurement region and a pattern density in the peripheral region where the second pattern exists, and to estimate a depth of the first pattern based on the obtained image signal of the depth measurement region and the pattern density in the peripheral region.

A multi-source illumination apparatus for illuminating a sample with charged particles, wherein beams, from a plurality of sources, are arranged such that a beam from at least one source intersects, at a plane of a condenser lens, with at least part of one other beam from a different one of the plurality of sources. The condenser lens is configured to separately collimate the received beams from each source. A manipulator array arrangement is configured to manipulate the collimated beams to generate one or more beams, in a single column, that include charged particles from the plurality of sources. The manipulator array arrangement includes a multi-beam generator configured to receive the plurality of substantially parallel substantially collimated beams generated by the deflector array, and generate a multibeam in dependence on the received plurality of substantially parallel substantially collimated beams, wherein the multi-beam includes a plurality of substantially collimated sub-beams.

Disclosed herein is an multi-array lens configured in use to focus a plurality of beamlets of charged particles along a multi-beam path, wherein each lens in the array comprises: an entrance electrode; a focusing electrode and a support. The focusing electrode is down beam of the entrance electrode along a beamlet path and is configured to be at a potential different from the entrance electrode. The support is configured to support the focusing electrode relative to the entrance electrode. The focusing electrode and support are configured so that in operation the lens generates a rotationally symmetrical field around the beamlet path.

Wafer-to-wafer and within-wafer image contrast variations can be identified and mitigated by extracting an image frame during recipe setup and then during runtime at the same location. Image contrast is determined for the two image frames. A ratio of the contrast for the two image frames can be used to determine contrast variations and focus variation.

An objective lens arrangement includes a first, second and third pole pieces, each being substantially rotationally symmetric. The first, second and third pole pieces are disposed on a same side of an object plane. An end of the first pole piece is separated from an end of the second pole piece to form a first gap, and an end of the third pole piece is separated from an end of the second pole piece to form a second gap. A first excitation coil generates a focusing magnetic field in the first gap, and a second excitation coil generates a compensating magnetic field in the second gap. First and second power supplies supply current to the first and second excitation coils, respectively. A magnetic flux generated in the second pole piece is oriented in a same direction as a magnetic flux generated in the second pole piece.