Space Charge Insensitive Electron Gun Designs
AssigneeKLA-Tencor Corporation
InventorsChristopher Sears, Luca Grella
Life of this patent
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Abstract
Electron gun systems with a particular inner width dimension, sweep electrodes, or a combination of a particular inner width dimension and sweep electrodes are disclosed. The inner width dimension may be less than twice a value of a Larmor radius of secondary electrons in a channel downstream of a beam limiting aperture, and a Larmor time for the secondary electrons may be greater than 1 ns. The sweep electrode can generates an electric field in a drift region, which can increase kinetic energy of secondary electrons in the channel.
Claims16
An electron gun system comprising:
- an electron source that directs a primary beam of electrons;
- a plate defining a beam limiting aperture, wherein the primary beam of electrons is projected through the beam limiting aperture;
- a magnetic field source that generates a magnetic field;
- a voltage source connected to the magnetic field source;
- and
- a channel that the primary beam of electrons is projected through after being projected through the beam limiting aperture, wherein the channel has an inner width dimension perpendicular to a direction the primary beam of electrons is projected, wherein the inner width dimension is less than or equal to twice a value of a Larmor radius of secondary electrons in the channel, and wherein a Larmor time for the secondary electrons is greater than 1 ns.
An electron gun system comprising:
- an electron source that directs a primary beam of electrons;
- a plate defining a beam limiting aperture, wherein the primary beam of electrons is projected through the beam limiting aperture;
- a magnetic field source that generates a magnetic field;
- a channel that the primary beam of electrons is projected through after being projected through the beam limiting aperture;
- and
- a sweep electrode that generates an electric field in a drift region, wherein the electric field increases kinetic energy of secondary electrons in the channel.
A method comprising:
- generating a primary beam of electrons with an electron source;
- projecting the primary beam of electrons through a beam limiting aperture;
- projecting the primary beam of electrons through a channel downstream of the beam limiting aperture, wherein secondary electrons in the channel have a Larmor radius and a Larmor time, wherein the channel has an inner width dimension perpendicular to a direction the primary beam of electrons is projected, wherein the inner width dimension is less than or equal to twice a value of the Larmor radius, and wherein the Larmor time for the secondary electrons is greater than 1 ns;
- and
- limiting the secondary electrons in the channel to one orbit or less.
Dependencies are inferred from the claim text.