Disclosed herein is a substrate stack comprising a plurality of substrates, wherein: each substrate in the substrate stack comprises at least one alignment opening set; the at least one alignment opening set in each substrate is aligned for a light beam to pass through corresponding alignment openings in each substrate; and each substrate comprises at least one alignment opening that has a smaller diameter than the corresponding alignment openings in the other substrates.

A system and method for defect inspection using voltage contrast in a charged particle system are provided. Some embodiments of the system and method include positioning the stage at a first position to enable a first beam of the plurality of beams to scan a first surface area of the wafer at a first time to generate a first image associated with the first surface area; positioning the stage at a second position to enable a second beam of the plurality of beams to scan the first surface area at a second time to generate a second image associated with the first surface area; and comparing the first image with the second image to enable detecting whether a defect is identified in the first surface area of the wafer.

A flood column for charged particle flooding of a sample, the flood column comprising a charged particle source configured to emit a charged particle beam along a beam path; a source lens arranged down-beam of the charged particle source; a condenser lens arranged down-beam of the source lens; and an aperture body arranged down-beam of the condenser lens, wherein the aperture body is for passing a portion of the charged particle beam; and wherein the source lens is controllable so as to variably set the beam angle of the charged particle beam down-beam of the source lens.

It is provided a charged particle beam manipulation device for a plurality of charged particle beamlets, the charged particle beam manipulation device including a lens having a main optical axis, the lens including at least a first array of multipoles, each multipole of the first array of multipoles configured to compensate for a lens deflection force on a respective charged particle beamlet of the plurality of charged particle beamlets, the lens deflection force being a deflection force produced by the lens on the respective charged particle beamlet towards the main optical axis of the lens.

A charged particle system generates a charged particle multi beam along a multi beam path. The charged particle system comprises an aperture array, a beam limit array and a condenser lens. In the aperture array are an array of apertures to generate from an up-beam charged particle source charged particle paths down-beam of the aperture array. The beam-limit array is down-beam of the aperture array. Defined in the beam-limit array is an array of beam-limit apertures for shaping the charged particle multi beam path. The condenser lens system is between the aperture array and the beam-limit array. The condenser lens system selectively operates different of rotation settings that define different ranges of beam paths between the aperture array and the beam-limit array. At each rotation setting of the condenser lens system, each beam-limit aperture of the beam-limit array lies on a beam path down-beam of the aperture array.

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.

A multi-charged particle beam writing apparatus according to one aspect of the present invention includes a region setting unit configured to set, as an irradiation region for a beam array to be used, the region of the central portion of an irradiation region for all of multiple beams of charged particle beams implemented to be emittable by a multiple beam irradiation mechanism, and a writing mechanism, including the multiple beam irradiation mechanism, configured to write a pattern on a target object with the beam array in the region of the central portion having been set in the multiple beams implemented.

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.

An improved source conversion unit of a charged particle beam apparatus is disclosed. The source conversion unit comprises a first micro-structure array including a plurality of micro-structures. The plurality of micro-structures is grouped into one or more groups. Corresponding electrodes of micro-structures in one group are electrically connected and driven by a driver to influence a corresponding group of beamlets. The micro-structures in one group may be single-pole structures or multi-pole structures. The micro-structures in one group have same or substantially same radial shifts from an optical axis of the apparatus. The micro-structures in one group have same or substantially same orientation angles with respect to their radial shift directions.

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.