US 11,791,132 B2
Aperture array with integrated current measurement
Albertus Victor Gerardus Mangnus, Eindhoven (NL); Maikel Robert Goosen, Eindhoven (NL); and Erwin Paul Smakman, Eindhoven (NL)
Assigned to ASML Netherlands B.V., Veldhoven (NL)
Filed by ASML Netherlands B.V., Veldhoven (NL)
Filed on Mar. 25, 2020, as Appl. No. 16/830,204.
Claims priority of application No. 19166009 (EP), filed on Mar. 28, 2019.
Prior Publication US 2020/0312619 A1, Oct. 1, 2020
Int. Cl. H01J 37/317 (2006.01); H01J 37/24 (2006.01); H01J 37/244 (2006.01); H01J 37/304 (2006.01)
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
OG exemplary drawing
 
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.