US4525629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Deflective focusing system for charged particle beam
Assignee: NTT Inc
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Filing: 1982-06-07
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Granted: 1985-06-25
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Expires: 2002-06-07
Abstract
Abstract A deflective focusing system includes a magnetic lens for focusing a charged particle beam, a plurality of rings made of magnetic material arranged substantially concentrically with the magnetic lens inside of the magnetic lens, the rings being arranged at spaced apart positions in the direction of the central axis of the magnetic lens so as to form a predetermined magnetic focusing field distribution, a one-stage electrostatic deflector having a plurality of deflection electrodes which are spaced apart in a circumferential direction of the magnetic lens, which are arranged substantially concentrically with the magnetic lens inside of the magnetic lens, and which extend in the direction of the central axis so as to form a predetermined electrostatic deflection field distribution, so that the charged particle beam passes through the concentrically arranged deflection electrodes to be deflected in accordance with a voltage applied to the deflection electrodes, and ring-like grounding electrodes disposed substantially concentrically with the magnetic lens on the object plane side and the image plane side of the electrostatic deflector along the passage of the charged particle beam. The electromagnetic field is adjusted by the deflector, the rings and the grounding electrodes to obtain small aberrations and a small landing angle.
Inventors
- 👤 Hirofumi Morita
- 👤 Teruo Hosokawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:52
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/147; H01J37/1472; H01J37/1474; H01J37/1477; H01J29/00; H01J29/46; H01J37/30; H01J37/3002; H01J37/3007
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
144 words
A deflective focusing system for a charged particle beam comprising: a magnetic lens for focusing a charged particle beam; a plurality of rings made of magnetic material arranged substantially concentric with said magnetic lens inside of said magnetic lens, said rings being arranged dividedly in the direction of the central axis of said magnetic lens so as to form a predetermined magnetic focusing field distribution; and a one-stage electrostatic deflector having a plurality of deflection electrodes which are divided in a circumferential direction of said magnetic lens, are arranged substatially concentric with said magnetic lens inside of said magnetic lens and are extended in the direction of said central axis so as to form a predetermined electrostatic deflection field distribution, the charged particle beam passing through said concentrically arranged deflection electrodes to be deflected in accordance with a voltage applied to said deflection electrodes.
Claim 2
Dependent Claim
144 words
A deflective focusing system for a charged particle beam comprising: a magnetic lens for focusing a charged particle beam; a plurality of rings made of magnetic material arranged substantially concentric with said magnetic lens inside of said magnetic lens, said rings being arranged dividedly in the direction of the central axis of said magnetic lens so as to form a predetermined magnetic focusing field distribution; and a one-stage electrostatic deflector having a plurality of deflection electrodes which are divided in a circumferential direction of said magnetic lens, are arranged substatially concentric with said magnetic lens inside of said magnetic lens and are extended in the direction of said central axis so as to form a predetermined electrostatic deflection field distribution, the charged particle beam passing through said concentrically arranged deflection electrodes to be deflected in accordance with a voltage applied to said deflection electrodes.
Claim 3
Dependent Claim
47 words
A deflective focusing system for a charged particle beam as claimed in claim 1, further comprising ring-like grounding electrodes which are disposed substantially concentric with said magnetic lens on the object and image plane sides of said electrostatic deflector along the passage of said charged particle beam.
Claim 4
Dependent Claim
64 words
A deflective focusing system for a charged particle beam as claimed in claim 2, wherein ring-like spacers made of non-magnetic material and having substantially the same diameter as said ring are inserted between said rings, so that the magnetic focusing field distribution is adjusted by the thicknesses of said rings in the direction of said central axis and the thicknesses of said ring-like spacers.
Claim 5
Dependent Claim
53 words
A deflective focusing system for a charged particle beam as claimed in claim 2 or 3, wherein a gap for adjusting the electrostatic deflection field is provided between said ring-like grounding electrodes and said electrostatic deflector, so that said electrostatic deflection field distribution is adjusted in accordance with the length of said gap.
Claim 6
Dependent Claim
43 words
A deflective focusing system for a charged particle beam as claimed in claim 4, wherein the inner diameter of said ring-like grounding electrode is more reduced than the inner diameter of said deflection electrode to have an abrupt fringe in the field distribution.
Claim 7
Dependent Claim
52 words
A deflective focusing system for a charged particle beam as claimed in claim 4, wherein said electrostatic deflector has the end portion on said image plane side shifted from the end portion of said ring on said image plane side toward said object plane side in the direction of said central axis.
Claim 8
Dependent Claim
31 words
A deflective focusing system for a charged particle beam as claimed in claim 2, wherein said electrostatic deflector has the inner diameter substantially equal to that of said ring-like grounding electrode.
Claim 9
Dependent Claim
104 words
A deflective focusing system for a charged particle beam as claimed in claim 7, further comprising a case having a first room, which is formed by said case and a sealing member made of nonmagnetic material, for accommodating the coil of said magnetic lens, a second room, which is formed by said sealing member, said electrostatic deflector and said grounding electrodes, for accommodating said rings, and a third room whose boundary is defined by said electrostatic deflector and said grounding electrodes and through which said charged particle beam passes, said sealing member sealing said second room vacuum-tightly and fixing said rings at predetermined positions.
Claim 10
Dependent Claim
38 words
A deflective focusing system for a charged particle beam as claimed in claim 8, wherein said case has a flange extended inwardly to cover said ring-like grounding electrode disposed on said object plane side of said electrostatic deflector.
Claim 11
Dependent Claim
32 words
A deflective focusing system for a charged particle beam as claimed in claim 2, wherein said ring-like grounding electrode on said image plane side has a flange for supporting said electrostatic deflector.
Claim 12
Dependent Claim
41 words
A deflective focusing system for a charged particle beam as claimed in claim 6, wherein a stigmator coil is wound on the periphery of a portion of said electrostatic deflector which is protruded from said rings toward said object plane side.
Claim 13
Dependent Claim
25 words
A deflective focusing system for a charged particle beam as claimed in claim 11, wherein a dynamic focusing coil is wound around said stigmator coil.
Claim 14
Dependent Claim
29 words
A deflective focusing system for a charged particle beam as claimed in claim 1 or 2, further comprising a shielding electrode around the outer periphery of said electrostatic deflector.
Claim 15
Dependent Claim
52 words
A deflective focusing system for a charged particle beam as claimed in claim 2, wherein said electrostatic deflector has the end portion on said image plane side shifted from the end portion of said ring on said image plane side toward said object plane side in the direction of said central axis.
Claim 16
Dependent Claim
41 words
A deflective focusing system for a charged particle beam as claimed in claim 14, wherein a stigmator coil is wound on the periphery of a portion of said electrostatic deflector which is protruded from said rings toward said object plane side.
Claim 17
Dependent Claim
25 words
A deflective focusing system for a charged particle beam as claimed in claim 15, wherein a dynamic focusing coil is wound around said stigmator coil.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |