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US 12,614,691 B2Granted
Charged particle source
AssigneeASML Netherlands B.V.
InventorShuai Li
Life of this patent
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Abstract
This invention provides a charged particle source, which comprises an emitter and means fo generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.
Claims20
An electron source for an electron beam inspection tool, comprising:
- an emitter configured to provide electrons to enable formation of an electron beam along an optical axis of the electron beam inspection tool;
- an extraction electrode configured to extract the electrons from a tip of the emitter;
- and
- a magnetic field generator configured to generate a magnetic field having:
- a first magnetic field distribution that influences the electrons between the tip of the emitter and the extraction electrode in a first operation mode, and
- a second magnetic field distribution that influences the electrons between the tip of the emitter and the extraction electrode in a second operation mode,
- wherein the first and second magnetic field distributions and the influences to the electrons due to the first and second magnetic field distributions change between the first operation mode and the second operation mode.
4 more elements
Dependencies are inferred from the claim text.