In one embodiment, a multi charged particle beam writing apparatus includes an acceleration lens comprised of an electrostatic lens including a plurality of electrodes and configured to accelerate a multi charged particle beam, two or more-stage objective lenses each comprised of a magnetic lens, and configured to focus the multi charged particle beam on a substrate, which has passed through a limiting aperture member, and three or more correction lenses including a first correction lens, a second correction lens and a third correction lens, and configured to correct an imaging state of the multi charged particle beam on the substrate. One or no electrostatic correction lens is placed in a magnetic field of each of the two or more-stage objective lenses. The first correction lens is an electrostatic correction lens that also serves as at least one of the plurality of electrodes of the acceleration lens.

A method includes operating a multiple particle beam system at different working points. The numerical aperture can be set for each of the working points in such a way that the resolution of the multiple particle beam system is optimal. In the process, the beam pitch between adjacent individual particle beams on the sample to be scanned is kept constant as a boundary condition. There are no mechanical reconfigurations of the system whatsoever for the purposes of varying the numerical aperture.

A multi-beam apparatus for observing a sample with high resolution and high throughput and in flexibly varying observing conditions is proposed. The apparatus uses a movable collimating lens to flexibly vary the currents of the plural probe spots without influencing the intervals thereof, a new source-conversion unit to form the plural images of the single electron source and compensate off-axis aberrations of the plural probe spots with respect to observing conditions, and a pre-beamlet-forming means to reduce the strong Coulomb effect due to the primary-electron beam.

An electron beam irradiation apparatus includes a first electrode being annular, arranged along the optical axis of the electron beam, at the downstream from the deflector, and in the magnetic field of the objective lens, to which a first potential being positive is variably applied, a second electrode being annular, arranged in the magnetic field of the objective lens and between the deflector and the first electrode, to which a second potential being positive and higher than the first potential is applied, and a third electrode being annular, arranged in the magnetic field of the objective lens and to be opposite to the second electrode with respect to the first electrode, to which a third potential lower than the first potential is applied.

A particle beam system and, such as a multi-beam particle microscope, can have a current intensity of individual particle beams that is flexibly set over large value ranges without structural modifications. The particle beam system can include a condenser lens system, a pre-multi-lens array with a specific pre-counter electrode and a pre-multi-aperture plate, and a multi-lens array. The system can includes a controller to supply adjustable excitations to the condenser lens system and the pre-counter electrode so that the charged particles are incident on the pre-multi-aperture plate in telecentric manner.

A method includes operating a multiple particle beam system at different working points. The numerical aperture can be set for each of the working points in such a way that the resolution of the multiple particle beam system is optimal. In the process, the beam pitch between adjacent individual particle beams on the sample to be scanned is kept constant as a boundary condition. There are no mechanical reconfigurations of the system whatsoever for the purposes of varying the numerical aperture.

The present invention provides apparatuses to inspect small particles on the surface of a sample such as wafer and mask. The apparatuses provide both high detection efficiency and high throughput by forming Dark-field BSE images. The apparatuses can additionally inspect physical and electrical defects on the sample surface by form SE images and Bright-field BSE images simultaneously. The apparatuses can be designed to do single-beam or even multiple single-beam inspection for achieving a high throughput.

A multi-beam apparatus for observing a sample with high resolution and high throughput and in flexibly varying observing conditions is proposed. The apparatus uses a movable collimating lens to flexibly vary the currents of the plural probe spots without influencing the intervals thereof, a new source-conversion unit to form the plural images of the single electron source and compensate off-axis aberrations of the plural probe spots with respect to observing conditions, and a pre-beamlet-forming means to reduce the strong Coulomb effect due to the primary-electron beam.

A multi-beam apparatus for observing a sample with high resolution and high throughput and in flexibly varying observing conditions is proposed. The apparatus uses a movable collimating lens to flexibly vary the currents of the plural probe spots without influencing the intervals thereof, a new source-conversion unit to form the plural images of the single electron source and compensate off-axis aberrations of the plural probe spots with respect to observing conditions, and a pre-beamlet-forming means to reduce the strong Coulomb effect due to the primary-electron beam.

A multi-mode low-voltage electron microscope operative in the accelerating voltage range of 3-50 kV is provided that include in the following order based on the direction of a primary electron beam (12): an electron beam source (1) to generate the primary electron beam (12), a first magnetostatic condenser lens means (3), a second magnetostatic condenser lens means (4), a condenser aperture (5), a sample holder (6), a magnetostatic objective lens means (7), an objective aperture (8), a first electrostatic projective lens means (9), and an end detection system (18) comprising a detection screen (11) and at least one detector.