Spherical aberration corrector, method of spherical aberration correction, and charged particle beam instrument

Patent metadata

Field	Value
Publication number	US-9256068-B2
Application number	US-201414338542-A
Country	US
Kind code	B2
Filing date	Jul 23, 2014
Priority date	Jul 24, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

A spherical aberration corrector is offered which permits a correction of deviation of the circularity of at least one of an image and a diffraction pattern and a correction of on-axis aberrations to be carried out independently. The spherical aberration corrector ( 100 ) is for use with a charged particle beam instrument ( 1 ) for obtaining the image and the diffraction pattern and has a hexapole field generating portion ( 110 ) for producing plural stages of hexapole fields, an octopole field superimposing portion ( 120 ) for superimposing an octopole on at least one of the plural stages of hexapole fields to correct deviation of the circularity of at least one of the image and diffraction pattern, and a deflection portion ( 130 ) for deflecting a charged particle beam.

First claim

The invention claimed is:

1. A spherical aberration corrector for use with a charged particle beam instrument for obtaining an image and a diffraction pattern, said spherical aberration corrector comprising:
a hexapole field generating portion for producing plural stages of hexapole fields;
an octopole field superimposing portion for superimposing an octopole field on at least one of the hexapole fields to correct deviation of the circularity of at least one of the image and diffraction pattern; and
a deflection portion for deflecting a charged particle beam.

2. The spherical aberration corrector as set forth in claim 1 , wherein said deflection portion adjusts a tilt of said charged particle beam within said at least one of said hexapole fields such that four-fold astigmatism induced by said octopole field is corrected.

3. A spherical aberration corrector for use with a charged particle beam instrument for obtaining an image and a diffraction pattern, said spherical aberration corrector comprising:
a hexapole field generating portion for producing plural stages of hexapole fields;
a quadrupole field superimposing portion for superimposing a quadrupole field on at least one of the plural stages of hexapole fields to correct deviation of the circularity of at least one of the image and diffraction pattern; and
a deflection portion for deflecting a charged particle beam.

4. The spherical aberration corrector as set forth in claim 3 , wherein said deflection portion adjusts a tilt of said charged particle beam within said at least one of said plural stages of hexapole fields such that star aberration induced by said quadrupole field is corrected.

5. A spherical aberration corrector for use with a charged particle beam instrument for obtaining an image and a diffraction pattern, said spherical aberration corrector comprising:
a hexapole field generating portion for producing plural stages of hexapole fields;
a deflecting field superimposing portion for superimposing a deflecting field on at least one of the plural stages of hexapole fields to correct deviation of the circularity of at least one of the image and diffraction pattern; and
a deflection portion for deflecting a charged particle beam.

6. The spherical aberration corrector as set forth in claim 5 , wherein said deflection portion adjusts a tilt of said charged particle beam within said at least one of said plural stages of hexapole fields such that star aberration induced by said deflecting field is corrected.

7. The spherical aberration corrector as set forth in any one of claims 1 to 6 , wherein said hexapole field generating portion has two stages of multipole elements.

8. The spherical aberration corrector as set forth in claim 7 , further comprising transfer lenses disposed between said two stages of multipole elements.

9. A method of spherical aberration correction implemented in a charged particle beam instrument for obtaining an image and a diffraction pattern, said method comprising the steps of:
producing plural stages of hexapole fields;
superimposing an octopole field on at least one of the hexapole fields to correct deviation of the circularity of at least one of said image and diffraction pattern; and
deflecting a charged particle beam to adjust a tilt of the beam within the at least one of the hexapole fields such that four-fold astigmatism induced by the octopole field is corrected.

10. A method of spherical aberration correction implemented in a charged particle beam instrument for obtaining an image and a diffraction pattern, said method comprising the steps of:
producing plural stages of hexapole fields;
superimposing a quadrupole field on at least one of the hexapole fields to correct deviation of the circularity of at least one of said image and diffraction pattern; and
deflecting a charged particle beam to adjust a tilt of the beam within the at least one of the hexapole fields such that star aberration induced by the quadrupole field is corrected.

11. A method of spherical aberration correction implemented in a charged particle beam instrument for obtaining an image and a diffraction pattern, said method comprising the steps of:
producing plural stages of hexapole fields;
superimposing a deflecting field on at least one of the hexapole fields to correct deviation of the circularity of at least one of said image and diffraction pattern; and
deflecting a charged particle beam to adjust a tilt of the beam within the at least one of the hexapole fields such that star aberration induced by the deflecting field is corrected.

12. The method of spherical aberration correction as set forth in any one of claims 9 to 11 , wherein said plural stages of hexapole fields are two stages of hexapole fields.

13. A charged particle beam instrument including a spherical aberration corrector as set forth in any one of claims 1 to 6 .

Assignees

• Jeol Ltd

Inventors

• Sawada Hidetaka
• Jimbo Yu

Classifications

• G02B27/42

  Diffraction optics {, i.e. systems including a diffractive element being designed for providing a diffractive effect}(G02B27/60 takes precedence) · CPC title

• H01J3/04

  Ion guns · CPC title

• H01J3/26

  Arrangements for deflecting ray or beam · CPC title

• G02B27/4205

  having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant · CPC title

• H01J37/28

  with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} · CPC title