Charged particle source
AssigneeASML Netherlands B.V.
InventorShuai Li
Life of this patent
Estimating the term…
Abstract
This invention provides a charged particle source, which comprises an emitter and means for 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
A method for providing an electron source for an electron beam inspection tool, comprising:
- providing, with an emitter, an electron beam along an optical axis of the electron beam inspection tool;
- extracting, with an extraction electrode, the electron beam from a tip of the emitter;
- and
- generating, with a magnetic lens, a magnetic field between the tip of the emitter and the extraction electrode, wherein a strength of the magnetic field increases to a peak point away from the tip of the emitter toward the extraction electrode.
An electron source for an electron beam inspection tool, comprising:
- an emitter configured to provide an electron beam along an optical axis of the electron beam inspection tool;
- an extraction electrode configured to extract the electron beam from a tip of the emitter;
- and
- a magnetic lens configured to generate a magnetic field between the tip of the emitter and the extraction electrode, wherein a strength of the magnetic field increases to a peak point away from the tip of the emitter toward the extraction electrode.
Dependencies are inferred from the claim text.