Aberration-corrected multibeam source, charged particle beam device and method of imaging or illuminating a specimen with an array of primary charged particle beamlets

Patent metadata

Field	Value
Publication number	US-10784072-B2
Application number	US-201816210554-A
Country	US
Kind code	B2
Filing date	Dec 5, 2018
Priority date	Jul 5, 2017
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

A charged particle beam device for inspection of a specimen with an array of primary charged particle beamlets is described. The charged particle beam device includes a charged particle beam source to generate a primary charged particle beam; a multi-aperture plate having at least two openings to generate an array of charged particle beamlets having at least a first beamlet having a first resolution on the specimen and a second beamlet having a second resolution on the specimen; an aberration correction element to correct at least one of spherical aberrations and chromatic aberrations of rotational symmetric charged particle lenses; and an objective lens assembly for focusing each primary charged particle beamlet of the array of primary charged particle beamlets onto a separate location on the specimen.

First claim

The invention claimed is:

1. A charged particle beam device for inspection of a specimen with an array of primary charged particle beamlets, comprising:
a charged particle beam source to generate a primary charged particle beam;
a multi-aperture plate having at least two openings to generate an array of primary charged particle beamlets having at least a first beamlet having a first resolution on the specimen and a second beamlet having a second resolution on the specimen;
an aberration correction element to correct at least one of spherical aberrations and chromatic aberrations of rotationally symmetric charged particle lenses, the aberration correction element being arranged such that the primary charged particle beamlets enter the aberration correction element at a first end and exit at an opposite end, propagating therein along the z-axis which is along the optical axis of the device; and
an objective lens assembly for focusing each primary charged particle beamlet of the array of primary charged particle beamlets onto a separate location on the specimen.

2. The charged particle beam device according to claim 1 , wherein the aberration correction element is configured to correct the difference between the first resolution on the specimen and the second resolution on the specimen and comprises at least two multipole elements.

3. The charged particle beam device according to claim 2 , wherein the at least two multipole elements each consists of 6 or more poles.

4. The charged particle beam device according to claim 2 , wherein the at least two multipole elements generate at least two hexapole fields.

5. The charged particle beam device according to claim 4 , wherein the aberration correction element further comprises at least one electrostatic or magnetic lens.

6. The charged particle beam device according to claim 2 , wherein the at least two multipole elements are two combined electric-magnetic quadrupole elements and the aberration correction element further comprises two electric or magnetic quadrupole elements.

7. The charged particle beam device according to claim 6 , wherein the aberration correction element further comprises at least three electric or magnetic octupole elements.

8. The charged particle beam device according to claim 1 , wherein the aberration correction element further comprises at least three electric octupole elements.

9. The charged particle beam device according to claim 1 , wherein the aberration correction element focuses the primary charged particle beam to reduce a divergence between the first beamlet and the second beamlet.

10. The charged particle beam device according to claim 1 , wherein the aberration correction element is provided between the multi-aperture plate and the objective lens assembly, and wherein the aberration correction element acts simultaneously on at least the first beamlet and the second beamlet.

11. The charged particle beam device according to claim 1 , further comprising:
a condenser lens assembly provided between the charged particle beam source and the multi-aperture plate.

12. The charged particle beam device according to claim 1 , wherein the objective lens assembly comprises an objective lens array to focus each beamlet of the array of primary charged particle beamlets individually.

13. The charged particle beam device according to claim 1 , wherein the objective lens assembly comprises a magnetic lens component acting on the array of primary charged particle beamlets.

14. The charged particle beam device according to claim 13 , further comprising:
a lens array provided between the multi-aperture plate and the objective lens assembly.

15. The charged particle beam device according to claim 13 , further comprising:
at least one of a lens or a deflector array, wherein the lens and the deflector array guides the array of primary charged particle beamlets through a coma free point of the objective lens assembly.

16. A charged particle beam device for inspection of a specimen with an array of primary charged particle beamlets, comprising:
a charged particle beam source to generate a primary charged particle beam;
a multi-aperture plate having at least two openings to generate an array of primary charged particle beamlets having at least a first beamlet having a first resolution on the specimen and a second beamlet having a second resolution on the specimen;
an aberration correction element to correct at least one of spherical aberrations and chromatic aberrations of rotationally symmetric charged particle lenses; and
an objective lens assembly for focusing each primary charged particle beamlet of the array of primary charged particle beamlets onto a separate location on the specimen; wherein
the aberration correction element is along an optical axis extending from the charged particle beam source to an objective lens assembly, and acts on the primary charged particle beamlets.

17. A charged particle beam device for inspection of a specimen with an array of primary charged particle beamlets, comprising:
a charged particle beam source to generate a primary charged particle beam;
a multi-aperture plate having at least two openings to generate an array of primary charged particle beamlets having at least a first beamlet having a first resolution on the specimen and a second beamlet having a second resolution on the specimen;
an aberration correction element to correct at least one of spherical aberrations and chromatic aberrations of rotationally symmetric charged particle lenses; and
an objective lens assembly for focusing each primary charged particle beamlet of the array of primary charged particle beamlets onto a separate location on the specimen; wherein
the aberration correction element is arranged such that the primary charged particle beamlets pass through the aberration correction element once.

Assignees

• Ict Integrated Circuit Testing Ges Fuer Halbleiterprueftechnik Mbh

Inventors

• Breuer John

Classifications

• H01J37/1472

  Deflecting along given lines · CPC title

• H01J37/12 Primary

  electrostatic · CPC title

• H01J37/28 Primary

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

• H01J37/153 Primary

  Electron-optical or ion-optical arrangements for the correction of image defects, e.g. stigmators · CPC title

• H01J2237/1534

  Aberrations · CPC title