Patent US4675524A successfully refreshed from Google Patents.
US4675524A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scanning particle microscope with diminished boersch effect
Assignee: Siemens AG
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Filing: 1986-02-21
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Granted: 1987-06-23
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Expires: 2006-02-21
Abstract
Abstract A beam generator in a scanning particle microscope reduces energetic Boersch effect on the probe diameter to improve resolution by enabling beam particles to traverse a first beam crossover point with low energy and subsequently reaccelerating the beam particles to high energies while traversing the microscope's electro-optical column for subsequent deceleration shortly before reaching a specimen. An extraction electrode is provided between a Wehnelt electrode and an anode at a positive potential relative to a cathode, wherein the positive potential of the extraction electrode is substantially less than a positive potential at the anode.
Inventors
- 👤 Juergen Frosien
- 👤 Rainer Spehr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:58
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/26; H01J37/28; H01J37/02; H01J37/04; H01J37/153
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
107 words
A scanning particle microscope, comprising: a particle beam generator having a cathode and an extraction electrode disposed between a Wehnelt electrode and an anode for generating a particle beam of primary particles; a beam-shaping lens system; means for focusing and deflecting the particle beam onto a specimen; at least one means for decelerating the primary particles in the beam path; said extraction electrode being maintained at a first potential which is positive relative to the potential of said cathode; and said anode being maintained at a second potential which is positive relative to the potential of said cathode, said second potential being greater than said first potential.
Claim 2
Dependent Claim
107 words
A scanning particle microscope, comprising: a particle beam generator having a cathode and an extraction electrode disposed between a Wehnelt electrode and an anode for generating a particle beam of primary particles; a beam-shaping lens system; means for focusing and deflecting the particle beam onto a specimen; at least one means for decelerating the primary particles in the beam path; said extraction electrode being maintained at a first potential which is positive relative to the potential of said cathode; and said anode being maintained at a second potential which is positive relative to the potential of said cathode, said second potential being greater than said first potential.
Claim 3
Dependent Claim
20 words
A scanning particle microscope as claimed in claim 1, wherein said second potential is a multiple of said first potential.
Claim 4
Dependent Claim
31 words
A scanning particle microscope as claimed in claim 1, wherein said focusing and deflecting means includes at least one magnetic lens and said decelerating means is disposed in said magnetic lens.
Claim 5
Dependent Claim
18 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating includes an electrostatic lens.
Claim 6
Dependent Claim
32 words
A scanning particle microscope as claimed in claim 1, wherein said focusing and deflecting means includes a plurality of lenses, and said means for decelerating is disposed between two of said lenses.
Claim 7
Dependent Claim
38 words
A scanning particle microscope as claimed in claim 1, wherein said focusing and deflecting means includes a plurality of lenses, and said means for decelerating is disposed in the particle beam path following the last of said lenses.
Claim 8
Dependent Claim
35 words
A scanning particle microscope as claimed in claim 1, wherein said focusing and deflecting means includes an objective lens and said means for decelerating is disposed in the particle beam path preceding said objective lens.
Claim 9
Dependent Claim
20 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating is formed of a two-electrode arrangement.
Claim 10
Dependent Claim
20 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating is formed of a multi-electrode arrangement.
Claim 11
Dependent Claim
18 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating is a net-shaped electrode.
Claim 12
Dependent Claim
17 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating is a diaphragm.
Claim 13
Dependent Claim
18 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating is a cylindrical lens.
Claim 14
Dependent Claim
18 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating is a single lens.
Claim 15
Dependent Claim
21 words
A scanning particle microscope as claimed in claim 1, wherein said means for decelerating is formed of an electrostatic immersion lens.
Claim 16
Dependent Claim
126 words
An improved particle beam generator for use in a scanning particle microscope having means for shaping and deflecting a particle beam and means for retarding the particle beam prior to encountering a specimen, the improvement comprising: a cathode at a first potential and defining a particle beam origin; a Wehnelt electrode spaced from said cathode for generating a source crossover point in the particle beam; an extraction electrode spaced from said Wehnelt electrode opposite said cathode and being at a second potential, said second potential being more positive than said first potential; an anode spaced from said extraction electrode opposite said cathode and being at a third potential, said third potential being more positive than said first potential and of greater magnitude than said second potential.
Claim 17
Dependent Claim
126 words
An improved particle beam generator for use in a scanning particle microscope having means for shaping and deflecting a particle beam and means for retarding the particle beam prior to encountering a specimen, the improvement comprising: a cathode at a first potential and defining a particle beam origin; a Wehnelt electrode spaced from said cathode for generating a source crossover point in the particle beam; an extraction electrode spaced from said Wehnelt electrode opposite said cathode and being at a second potential, said second potential being more positive than said first potential; an anode spaced from said extraction electrode opposite said cathode and being at a third potential, said third potential being more positive than said first potential and of greater magnitude than said second potential.
Claim 18
Dependent Claim
18 words
A beam generator as claimed in claim 15, wherein said first and second potentials differ by 2 kV.
Claim 19
Dependent Claim
18 words
A beam generator as claimed in claim 15, wherein said first and third potentials differ by 10 kV.
Claim 20
Dependent Claim
101 words
A particle beam generator for use in a scanning particle microscope having a beam-shaping lens system, a means for focusing and deflecting a particle beam onto a specimen, and a means for decelerating beam particles prior to encountering a specimen, comprising mounted sequentially in the particle beam direction: a cathode maintained at a cathode potential; a Wehnelt electrode; an extraction electrode maintained at an extraction potential which is positive relative to said cathode potential; and an anode maintained at an anode potential which is positive relative to said cathode potential, said anode potential being greater in magnitude than said extraction potential.
Claim 21
Dependent Claim
101 words
A particle beam generator for use in a scanning particle microscope having a beam-shaping lens system, a means for focusing and deflecting a particle beam onto a specimen, and a means for decelerating beam particles prior to encountering a specimen, comprising mounted sequentially in the particle beam direction: a cathode maintained at a cathode potential; a Wehnelt electrode; an extraction electrode maintained at an extraction potential which is positive relative to said cathode potential; and an anode maintained at an anode potential which is positive relative to said cathode potential, said anode potential being greater in magnitude than said extraction potential.
Claim 22
Dependent Claim
29 words
A particle beam generator as claimed in claim 18, wherein said cathode potential is -l kV, said extraction potential is +l kV, and said anode potential is +9 kV.
Claim 23
Dependent Claim
107 words
A scanning particle microscope comprising: means for generating a beam of primary particles including in the direction of beam generation: a cathode, a Wehnelt electrode, an extractor electrode, and an anode, said extraction electrode and said anode being maintained at a positive potential relative to said cathode, the potential of said anode being of substantially greater magnitude than the potential of said extraction electrode; means for focusing and directing said beam of primary particles; means for decelerating said beam of primary particles; whereby said particles in the beam path are at relatively low energies before said extraction electrode and at relatively high energies after said extraction electrode.
Claim 24
Dependent Claim
107 words
A scanning particle microscope comprising: means for generating a beam of primary particles including in the direction of beam generation: a cathode, a Wehnelt electrode, an extractor electrode, and an anode, said extraction electrode and said anode being maintained at a positive potential relative to said cathode, the potential of said anode being of substantially greater magnitude than the potential of said extraction electrode; means for focusing and directing said beam of primary particles; means for decelerating said beam of primary particles; whereby said particles in the beam path are at relatively low energies before said extraction electrode and at relatively high energies after said extraction electrode.
References Cited (Backward Citations)
US3691377A
Cited
US4330707A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-22 | 1990-12-22 | 1991-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-22 | 1994-12-22 | 1995-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-22 | 1998-12-22 | 1999-06-23 | $7700.00 | Window Closed / Lapsed |