Focusing system and method for a charged particle imaging system
AssigneesApplied Materials Israel Ltd., Carl Zeiss AG
InventorSteven Robert Rogers
Life of this patent
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Abstract
Apparatus for focusing a charged particle beam onto a surface, including a charged particle beam generator which is adapted to project the charged particle beam onto a location on the surface, thereby causing charges to be emitted from the location. The apparatus further includes an imaging detector which is adapted to receive the charges so as to form an image of the location, and an aberrating element which is positioned before the imaging detector and which is adapted to produce an aberration in the image. A processor is adapted to receive the image and to adjust at least one of the charged particle beam generator and a position of the surface in response to the aberration.
Claims30
Apparatus, comprising:
- a charged particle beam generator adapted to project a charged particle beam onto a location on a surface of a specimen so as to form an array of spots on the location, thereby causing released electrons to be emitted from the location;
- an imaging detector adapted to receive the released electrons via an imaging path from the surface of the specimen to the imaging detector and to form an image of the location from said released electrons;
- an aberrating element positioned in the imaging path between the specimen and the imaging detector and adapted to produce an aberration in the image;
- and
- a processor adapted to
- generate, from the aberration, a focus error signal;
- and,
- in response to said focus error signal, adjust at least one of the charged particle beam and a position of the surface so as to minimize an absolute value of a magnitude of the focus error signal.
A method, comprising:
- projecting a charged particle beam onto a location on a surface of a specimen, thereby causing released electrons to be emitted from the location;
- in an imaging path between the specimen and an imaging detector, passing the released electrons emitted from the location through an aberrating element;
- receiving, via the imaging path and at the imaging detector, the released electrons emitted from the location and forming an image of the location therefrom, said image having an aberration produced by the aberrating element;
- generating, from the aberration, a focus error signal;
- and
- adjusting, in response to said focus error signal, at least one of the charged particle beam and a position of the surface so as to minimize an absolute value of a magnitude of the focus error signal.
Apparatus, comprising:
- a charged particle beam generator adapted to project a charged particle beam onto a location on a surface of a specimen, thereby causing released electrons to be emitted from the location;
- an imaging detector adapted to receive the released electrons via an imaging path from the surface of the specimen to the imaging detector and to form an image of the location from said released electrons;
- an aberrating element positioned in the imaging path between the specimen and the imaging detector and adapted to produce an aberration in the image;
- and
- a processor adapted to
- generate, from the aberration, a focus error signal;
- and,
- in response to said focus error signal, adjust at least one of the charged particle beam and a position of the surface so as to minimize an absolute value of a magnitude of the focus error signal.
A method, comprising:
- projecting a charged particle beam onto a location on a surface of a specimen, thereby causing released electrons to be emitted from the location;
- in an imaging path between the specimen and an imaging detector, passing the released electrons emitted from the location through an aberrating element;
- receiving, via the imaging path and at the imaging detector, the released electrons emitted from the location and forming an image of the location therefrom, said image having an aberration produced by the aberrating element;
- generating, from the aberration, a focus error signal;
- adjusting, in response to said focus error signal, at least one of the charged particle beam and
- a position of the surface so as to minimize an absolute value of a magnitude of the focus error signal.
Dependencies are inferred from the claim text.