Apparatus of plural charged-particle beams
AssigneeASML Netherlands B.V.
InventorsShuai Li, Weiming Ren, Xuedong Liu, Juying Dou, Xuerang Hu, Zhongwei Chen
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Abstract
A multi-beam apparatus for observing a sample with high resolution and high throughput and in flexibly varying observing conditions is proposed. The apparatus uses a movable collimating lens to flexibly vary the currents of the plural probe spots without influencing the intervals thereof, a new source-conversion unit to form the plural images of the single electron source and compensate off-axis aberrations of the plural probe spots with respect to observing conditions, and a pre-beamlet-forming means to reduce the strong Coulomb effect due to the primary-electron beam.
Claims20
A non-transitory computer readable medium storing a set of instructions that is executable by one or more processors of a multi-beam apparatus to cause the multi-beam apparatus to perform operations to form multiple electron beamlets, the operations comprising:
- emitting an electron beam from an electron source;
- separating the electron beam into the multiple electron beamlets by cutting off a portion of the electron beam using a pre-beamlet-forming aperture array;
- collimating the multiple electron beamlets;
- and
- limiting currents of the multiple electron beamlets by further cutting off peripheral electrons of multiple electron beamlets at a beam-limit openings of a source-conversion unit,
- wherein the pre-beamlet-forming aperture array is positioned proximate to the electron source and between the electron source and the source-conversion unit.
A non-transitory computer readable medium storing a set of instructions that is executable by one or more processors of a multi-beam apparatus to cause the multi-beam apparatus to perform operations to form multiple electron beamlets, the operations comprising:
- emitting an electron beam from an electron source;
- separating the electron beam into the multiple electron beamlets by cutting off a portion of the electron beam using a pre-beamlet-forming aperture array;
- and
- focusing the multiple electron beamlets with multiple electron optics elements to form multiple parallel images of the electron source, respectively,
- wherein the pre-beamlet-forming aperture array is positioned proximate to the electron source and between the electron source and a source-conversion unit.
Dependencies are inferred from the claim text.