CPC H01J 37/1474 (2013.01) [H01J 37/06 (2013.01); H01J 37/10 (2013.01); H01J 37/1477 (2013.01); H01J 37/1478 (2013.01); H01J 37/28 (2013.01); H01J 2237/024 (2013.01); H01J 2237/0453 (2013.01); H01J 2237/0492 (2013.01); H01J 2237/103 (2013.01); H01J 2237/1205 (2013.01); H01J 2237/1516 (2013.01); H01J 2237/1534 (2013.01); H01J 2237/1536 (2013.01)] | 22 Claims |
1. A multi-beam apparatus for observing a surface of a sample, comprising:
a charged particle source configured to generate a charged particle beam;
a condenser lens configured to collimate the charged particle beam to be perpendicularly incident onto a source conversion unit that is configured to form a plurality of beamlets from the charged particle beam,
wherein the source conversion unit comprises:
a plurality of electron optics elements configured to direct the plurality of beamlets towards a primary optical axis of the multi-beam apparatus using at least two different deflection angles; and
a plurality of beam-limit openings configured to limit currents of the plurality of beamlets.
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