The present disclosure provides an inspection system and a method of stray field mitigation. The system includes an array of electron beam columns, a first permanent magnet array, and a plurality of shielding plates. The array of electron beam columns each includes an electron source configured to emit electrons toward a stage. The first permanent magnet array is configured to condense the electrons from each electron source into an array of electron beams. The first permanent magnet array is arranged at a first end of the array of electron beam columns. The plurality of shielding plates extend across the array electron beam columns downstream of the first permanent magnet array in a direction of electron emission. The array of electron beams pass through a plurality of apertures in each of the plurality of shielding plates, which reduces stray magnetic field in a radial direction of the array of electron beams.

This invention provides a charged particle source, which comprises an emitter and means of generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

This invention provides a charged particle source, which comprises an emitter and means of generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

Apparatus and methods for selectively transmitting objects of interest from a first reservoir to a second reservoir are disclosed. The apparatus includes electromagnetic focusing apparatus configured to interact with objects of interest to induce a change in a property of the objects of interest so as to increase the probability that the objects of interest through a throat diffusively coupling the first reservoir and the second reservoir.

A multi-column scanning electron microscopy (SEM) system is disclosed. The SEM system includes a source assembly. The source assembly includes two or more electron beam sources configured to generate a plurality of electron beams. The source assembly also includes two or more sets of positioners configured to actuate the two or more electron beam sources. The SEM system also includes a column assembly. The column assembly includes a plurality of substrate arrays. The column assembly also includes two or more electron-optical columns formed by a set of column electron-optical elements bonded to the plurality of substrate arrays. The SEM system also includes a stage configured to secure a sample that at least one of emits or scatters electrons in response to the plurality of electron beams directed by the two or more electron-optical columns to the sample.

A charged particle optical system includes a permanent magnetic lens disposed closer to an object than a central point between a charged particle beam source and the object in an optical axis direction of the charged particle optical system, an electromagnetic lens disposed such that a position of at least a part of the electromagnetic lens overlaps the permanent magnetic lens in the optical axis direction of the charged particle optical system, and an electrostatic lens disposed such that a position of at least a part of the electrostatic lens overlaps at least one of the permanent magnetic lens and the electromagnetic lens in the optical axis direction of the charged particle optical system.

A charged particle optical system includes a permanent magnetic lens disposed closer to an object than a central point between a charged particle beam source and the object in an optical axis direction of the charged particle optical system, an electromagnetic lens disposed such that a position of at least a part of the electromagnetic lens overlaps the permanent magnetic lens in the optical axis direction of the charged particle optical system, and an electrostatic lens disposed such that a position of at least a part of the electrostatic lens overlaps at least one of the permanent magnetic lens and the electromagnetic lens in the optical axis direction of the charged particle optical system.

An object of the invention is to efficiently execute aberration correction in an electron microscope including an aberration corrector that corrects aberration using a multipole lens. The electron microscope according to the invention includes an aberration corrector that includes first and second multipole lenses, a transfer lens, and an adjustment lens, in which the first multipole lens is configured to correct third-order spherical aberration by adjusting a lens current, and third-order spherical aberration and fifth-order spherical aberration are collectively corrected by adjusting a transfer lens current while changing an adjustment lens current.

An object of the invention is to efficiently execute aberration correction in an electron microscope including an aberration corrector that corrects aberration using a multipole lens. The electron microscope according to the invention includes an aberration corrector that includes first and second multipole lenses, a transfer lens, and an adjustment lens, in which the first multipole lens is configured to correct third-order spherical aberration by adjusting a lens current, and third-order spherical aberration and fifth-order spherical aberration are collectively corrected by adjusting a transfer lens current while changing an adjustment lens current.

This invention provides a charged particle source, which comprises an emitter and means fo generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.