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US 2026/0290744 A1Published application
Distortion optimized multi-beam scanning system
AssigneeCarl Zeiss MultiSEM GmbH
InventorsDirk ZEIDLER, Thomas SCHMID
Life of this patent
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Abstract
A multi-beam charged particle inspection system and a method of operating a multi-beam charged particle inspection system for wafer inspection with high throughput and with high resolution and high reliability comprise a mechanism for reduction and compensation of a scanning induced aberration, such as a scanning distortion of a collective multi-beam raster scanner for beamlets propagating at an angle with respect to the optical axis of the multi-beam charged particle inspection system.
Claims20
A multi-beam charged particle microscope, comprising:
- a beamlet generator configured to generate a first primary charged particle beamlet;
- an object irradiation unit configured to illuminate with the first primary charged particle beamlet an image field of a surface of a sample in an object plane of the multi-beam charged particle microscope;
- a raster scanner comprising a set of deflection electrodes and an intersection volume, the multi-beam charged particle microscope configured so that, during use, the first primary charged particle beamlet traverses the intersection volume;
- a control unit configured to provide a scanning voltage difference to the set of deflection electrodes to scan deflect the first primary charged particle beamlet over the image field in a first direction;
- and
- a scanning corrector configured to generate a scanning correction field configured to influence the first primary charged particle beamlet,
- wherein:
- the image field having a lateral extension of at least five micrometers;
- the control unit is configured to provide the scanning voltage difference to the scanning corrector;
- and
- the scanning corrector is configured to reduce a scanning induced aberration of the first primary charged particle beamlet synchronized with the scanning deflection of the first primary charged particle beamlet.
8 more elements
A multi-beam charged particle microscope, comprising:
- a multi-beamlet generator configured to generate a plurality of primary beamlets, the plurality of primary beamlets comprising first and second primary beamlets;
- an object irradiation unit configured to illuminate an image patch of a surface of a wafer arranged in an object plane to generate a plurality of secondary electron beamlets emitting from the surface;
- a collective multi-beam raster scanner configured to perform a collective raster scanning of the plurality of primary beamlets to form an image scan of the image patch, the image scan comprising the first primary beamlet being scanned over a first image subfield and the second primary beamlet being synchronously scanned over a second image subfield of the image patch, the collective multi-beam raster scanner defining an intersection volume;
- a detection unit comprising a projection system and an image sensor, the projection system configured to image the plurality of secondary electron beamlets onto the image sensor to acquire a digital image;
- a
- a first scanning corrector configured to reduce a scanning induced distortion difference between the first primary beamlet in the first image subfield and the second primary beamlet in the second image subfield.
3 more elements
A method of operating a multi-beam charged particle microscope, the method comprising:
- generating a scanning voltage difference;
- providing the scanning voltage difference to a collective multi-beam raster scanner to collectively deflect scan a plurality of primary beamlets with the collective multi-beam raster scanner in a first direction;
- generating from the scanning voltage difference a first scanning correction voltage difference synchronized with the scanning voltage difference;
- and
- providing the first scanning correction voltage difference to a deflection element of a scanning corrector for reduction of a scanning induced aberration of an individual beamlet of the plurality of primary beamlets.
2 more elements
Dependencies are inferred from the claim text.