Energy filter for charged particle beam apparatus
AssigneeHermes Microvision, Inc.
InventorsWeiming Ren, Shuai Li, Zhongwei Chen
Life of this patent
Estimating the term…
Abstract
This invention provides a method for improving performance of a reflective type energy filter for a charged particle beam, which employs a beam-adjusting lens on an entrance side of a potential barrier of the energy filter to make the charged particle beam become a substantially parallel beam to be incident onto the potential barrier. The method makes the energy filter have both a fine energy-discrimination power over a large emission angle spread and a high uniformity of energy-discrimination powers over a large FOV. A LVSEM using this method in the energy filter can obviously improve image contrast. The invention also provides multiple energy-discrimination detection devices formed by using the advantages of the method.
Claims6
An energy filter, comprising:
- a grid electrode being set at a first potential to form a potential barrier;
- and,
- a beam-adjusting lens being excited to make a charged particle beam become a substantially parallel beam to be incident onto said potential barrier,
- wherein a first plurality of particles of said charged particle beam, which has initial kinetic energies higher than a specific value and thus is able to cross said potential barrier, passes through said grid electrode and forms an exiting beam, while a second plurality of particles of said charged particle beam, which has initial kinetic energies not higher enough to be able to cross said potential barrier, is reflected back from said grid electrode and forms a reflection beam,
- wherein an optical axis of said beam-adjusting lens is an optical axis of said energy filter.
Dependencies are inferred from the claim text.