CPC H01J 37/3177 (2013.01) [H01J 37/243 (2013.01); H01J 37/244 (2013.01); H01J 37/3045 (2013.01); H01J 2237/0435 (2013.01)] | 18 Claims |
1. A multi-beam apparatus for inspecting a sample, comprising:
a charged-particle source configured to generate a primary charged-particle beam;
an aperture array comprising:
a plurality of apertures configured to form a plurality of beamlets from the primary charged-particle beam; and
a plurality of detectors disposed on a beam entrance side of the aperture array with respect to the primary charged-particle beam and along an inside edge of a virtual boundary representing a desired size and position of the primary charged-particle beam incident on the aperture array, the plurality of detectors configured to accumulate electric charge of at least a portion of the primary charged-particle beam irradiating the aperture array; and
a controller having circuitry coupled to the plurality of detectors and the charged-particle source, the circuitry configured to:
change an operation mode of the plurality of detectors to switch between a detection mode and a monitoring mode, wherein, in the detection mode, the controller enables the plurality of detectors to accumulate electric charge for a first predetermined time, and in the monitoring mode, the controller enables the plurality of detectors to accumulate electric charge for a second predetermined time that is different from the first predetermined time and to continuously monitor a drift of the primary charged-particle beam incident on the aperture array based on electric charges accumulated by the plurality of detectors, and
adjust a parameter of the charged-particle source to correct the drift of the primary charged-particle beam based on the electric charges accumulated by the plurality of detectors while the sample is inspected.
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