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Title: Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

Abstract

Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

Inventors:
 [1]
  1. (Dune Acres, IN)
Publication Date:
Research Org.:
Argonne National Laboratory (ANL), Argonne, IL
OSTI Identifier:
872959
Patent Number(s):
US 6051839
Assignee:
Arch Development Corporation (Chicago, IL) ANL
DOE Contract Number:
FE02-86ER60437
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
magnetic; lens; apparatus; high-resolution; scanning; electron; microscopes; lithographic; processes; disclosed; beam; charged; particlesis; brought; focus; means; field; situated; target; position; illustrative; embodiments; employed; microscopeas; sole; focusing; particular; accelerating; voltage; 10; 30; 000; embodiment; comprises; electrically-conducting; coil; arranged; axis; pole; piece; extending; space; surrounded; dipole; virtual; monopole; fabricated; variety; materials; including; permanent; magnets; superconducting; coils; magnetizable; spheres; needles; contained; energy-conducting; multiple-array; simultaneous; consecutive; imaging; multiple; images; single; specimens; provides; methods; devices; useful; particle; beams; scanning electron; superconducting coils; magnetic lens; electron microscope; superconducting coil; particle beam; apparatus comprises; charged particles; permanent magnet; magnetic field; electron beam; permanent magnets; charged particle; particle beams; lens apparatus; provides apparatus; apparatus comprise; multiple images; target position; conducting coils; electron microscopes; illustrative embodiment; pole piece; accelerating voltage; magnetic pole; /250/

Citation Formats

Crewe, Albert V. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes. United States: N. p., 2000. Web.
Crewe, Albert V. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes. United States.
Crewe, Albert V. 2000. "Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes". United States. doi:. https://www.osti.gov/servlets/purl/872959.
@article{osti_872959,
title = {Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes},
author = {Crewe, Albert V.},
abstractNote = {Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2000,
month = 1
}

Patent:

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  • Disclosed are lens apparatus in which a beam of charged particles is brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscope as the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of themore » beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.« less
  • A lens apparatus is disclosed in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope. 6 figs.
  • A lens apparatus in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope.
  • An improved specimen cell for use in the evacuated chamber of a directed beam irradiation device having an electron beam is described comprising: means for preventing dehydration and disruption of a specimen placed in the cell including closed specimen means for mounting and at least partially containing the specimen; means for defining a single aperture between the specimen and the electron beam when the beam is directed towards the specimen, the aperture comprising a means, sized and geometrically configured, for bidirectionally passing electrons and for restricting passage of vapor from within to without the specimen means; and door means mountedmore » on a pivotable arm for movement between an opened position and a closed position, for permitting bidirectional electron flow in the open position and for blocking the single aperture and for preventing passage of vapor from within to without the specimen means in the closed position. The door means comprise a backing metal plate attached to the arm and a facing of elastometric material for blocking the aperture.« less
  • A confocal scanning transmission electron microscope which includes an electron illumination device providing an incident electron beam propagating in a direction defining a propagation axis, and a precision specimen scanning stage positioned along the propagation axis and movable in at least one direction transverse to the propagation axis. The precision specimen scanning stage is configured for positioning a specimen relative to the incident electron beam. A projector lens receives a transmitted electron beam transmitted through at least part of the specimen and focuses this transmitted beam onto an image plane, where the transmitted beam results from the specimen being illuminatedmore » by the incident electron beam. A detection system is placed approximately in the image plane.« less