Aberration correction device and method for operating same
AssigneeICT Integrated Circuit Testing Gesellschaft für Halbleiterprüftechnik mbH
InventorJuergen Frosien
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Abstract
The present invention provides an aberration correction device (100). The aberration correction device comprises a Wien filter element (110), a quadrupole element (310) for compensating a focusing property of the Wien filter element (110), and at least one multipole element (410) for spherical aberration correction. The Wien filter element (110) and said quadrupole element (310) are adapted to generate, in combination, an astigmatic image. Furthermore, the at least one multipole element (410) is adapted to act essentially in a plane of sagittal or meridional focus of the astigmatic image. Thereby, chromatic aberration is reduced as well as spherical aberration can be corrected.
Claims32
An aberration correction device, comprising:
- a Wien filter element;
- a quadrupole element (310) for compensating a focusing property of said Wien filter element;
- and
- at least one multipole element for spherical aberration correction, wherein said Wien filter element and said quadrupole element are adapted to generate, in combination, an astigmatic image and wherein said at least one multipole element is adapted to act essentially in a plane of sagittal or meridional focus of said astigmatic image.
A charged particle beam device comprising:
- a source of a beam of charged particles;
- an aberration correction device comprising:
- a Wien filter element;
- a quadrupole element for compensating a focusing property of said Wien filter element;
- and
- at least one multipole element for spherical aberration correction, wherein said Wien filter element and said quadrupole element are adapted to generate, in combination, an astigmatic image and wherein said at least one multipole element is adapted to act essentially in a plane of sagittal or meridional focus of said astigmatic image;
- and
- an objective lens for focusing said beam of charged particles on a surface of a specimen to be inspected.
A method of operating a charged particle device comprising:
- producing a substantially stigmatic beam of charged particles;
- providing an aberration correction device, comprising:
- a Wien filter element;
- a quadrupole element for compensating a focusing property of said Wien filter element;
- and
- at least one multipole element for spherical aberration correction, wherein said Wien filter element and said quadrupole element are adapted to generate, in combination, an astigmatic image and wherein said at least one multipole element is adapted to act essentially in a plane of sagittal or meridional focus of said astigmatic image;
- controlling said Wien filter element and said quadrupole element so that their combined action generates an astigmatic image of the beam;
- and
- controlling said at least one multipole element so that a spherical aberration in a plane perpendicular to the plane of a crossover associated with said at least one multipole element is corrected.
Dependencies are inferred from the claim text.