Apparatus of Plural Charged-Particle Beams

摘要

A multi-beam apparatus for observing a sample with high resolution and high throughput is proposed. In the apparatus, a source-conversion unit changes a single electron source into a virtual multi-source array, a primary projection imaging system projects the array to form plural probe spots on the sample, and a condenser lens adjusts the currents of the plural probe spots. In the source-conversion unit, the image-forming means is on the upstream of the beamlet-limit means, and thereby generating less scattered electrons. The image-forming means not only forms the virtual multi-source array, but also compensates the off-axis aberrations of the plurality of probe spots.

主权项

1. A method to configure a source-conversion unit for forming a virtual multi-source array from an electron source, comprising:
providing an image-forming means which comprises an upper layer with a plurality of upper 4-pole structures and a lower layer with a plurality of lower 4-pole structures; and providing a beamlet-limit means which is below said image-forming means and comprises a plurality of beam-limit openings,
wherein each upper 4-pole structure is above and aligned with one corresponding lower 4-pole structure, both have a 45° difference in azimuth and form a pair of 4-pole structures, and therefore said plurality of upper 4-pole structures and said plurality of lower 4-pole structures form a plurality of pairs of 4-pole structures,wherein said plurality of beam-limit openings is aligned with said plurality of pairs of 4-pole structures respectively,wherein one pair of 4-pole structure functions as a micro-deflect to deflect one beamlet of an electron beam generated by said electron source to form a virtual image thereof, a micro-lens to focus said one beamlet to a desired degree, and/or a micro-stigmator to add a desired amount of astigmatism aberration to said one beamlet.