Objective lens for a charged particle beam device
AssigneeICT Integrated Circuit Testing Gesellschaft für Halbleiterprüftechnik mbH
InventorPavel Adamec
Life of this patent
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Abstract
An improved objective lens for a charged particle beam device is constituted by, among other things, a magnetic lens that creates a first magnetic field for focussing the charged particle beam onto the specimen. Furthermore, a deflector is integrated into the magnetic lens by providing at least one additional coil arrangement that creates a second magnetic field used to deflect the charged particle beam. Thereby, the second magnetic field is guided through at least one of the pole pieces of the magnetic lens. The present invention also provides an improved column for a charged particle beam device including the improved objective lens.
Claims26
An objective lens for a charged particle beam device, which is used to examine or to modify a specimen, said objective lens comprising:
- a) at least two pole pieces whereby a lower pole piece is spaced from an upper pole piece by a pole piece gap, said upper and lower pole pieces providing a path for the charged particle beam
- b) at least one first excitation coil arrangement for generating a first magnetic field between said upper pole piece and said lower pole piece to focus the charged particle beam onto the specimen, and
- c) a magnetic deflector having at least one second excitation coil arrangement for generating a second magnetic field to deflect the charged particle beam, said second magnetic field being guided through at least one of the pole pieces.
A column for a charged particle beam device, which is used to examine or to modify a specimen, said column comprising:
- a) a particle source for providing a beam of charged particles;
- b) a detector for measuring at least one secondary product and/or back-scattered particles coming from the specimen;
- and
- c) an objective lens according to one of the preceding claims for focusing the charged particle beam onto the specimen.
A column for a charged particle beam device, which is used to examine or to modify a specimen, said column comprising:
- a) a particle source for providing a beam of charged particles;
- b) a detector for measuring at least one secondary product and/or backscattered particles coming from the specimen;
- c) an objective lens for focusing the charged particle beam onto the specimen;
- and
- d) a magnetic deflector having at least one excitation coil arrangement for generating a magnetic field to deflect the charged particle beam and at least one deflector pole piece extending substantially perpendicular to the optical axis of the column,
- said magnetic deflector being arranged between the objective lens and specimen,
- wherein a surface of said deflector pole piece faces a surface of a lower pole piece of said objective lens and extends substantially parallel to said surface so that at least part of the magnetic flax of the deflector closes through the lower pole piece of said objective lens, and
- whereby the objective lens concentrates the magnetic field of the deflector in a region close to the specimen.
Dependencies are inferred from the claim text.