US3857090A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Generation of beams of charged particles
Assignee: National Research Development Corp UK
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Filing: 1973-06-04
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Granted: 1974-12-24
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Expires: 1993-06-04
Abstract
Abstract Apparatus for and methods of monitoring the current comprised by a beam of charged particles, for example a focussed ion beam as used for ion implantation of surfaces such as semiconductor circuit substrates, is described. The beam is amplitude modulated and the resultant corresponding modulation of the magnetic field strength of the beam is detected, for example by a toroidal coil, to produce an output signal proportional to the field strength modulation and therefore proportional to the beam current. A plurality, for example four, of said output signals may be derived from positions spaced around the beam to enable any deviation of the beam from the desired path to be determined, and any deviation signal obtained may be used to return the beam to the desired path.
Inventors
- 👤 D Chick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:37
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/30; H01J37/304; H01J37/3045; G; G01; G01R; G01R19/00; G01R19/08; G01R33/00; G01R33/02; G01R33/028; H01J2237/00; H01J2237/245; H01J2237/24507; H01J2237/30; H01J2237/304; H01J2237/30472; H01J2237/317; H01J2237/31749
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
134 words
Apparatus for monitoring the current comprised by a beam of charged particles, comprising means for modulating the amplitude of said beam to thereby correspondingly modulate the strength of the magnetic field of said beam, detector means responsive to the magnetic field of said beam to provide at least three output signals each corresponDing to the modulation of the strength of the magnetic field of said beam at a respective one of a plurality of positions equally spaced around a desired path of movement of said beam, and means for comparing and developing from said at least three output signals a pair of position signals each indicating the position of said beam along a respective one of a pair of orthogonal axes perpendicular to and passing through said desired path of movement of said beam.
Claim 2
Dependent Claim
134 words
Apparatus for monitoring the current comprised by a beam of charged particles, comprising means for modulating the amplitude of said beam to thereby correspondingly modulate the strength of the magnetic field of said beam, detector means responsive to the magnetic field of said beam to provide at least three output signals each corresponDing to the modulation of the strength of the magnetic field of said beam at a respective one of a plurality of positions equally spaced around a desired path of movement of said beam, and means for comparing and developing from said at least three output signals a pair of position signals each indicating the position of said beam along a respective one of a pair of orthogonal axes perpendicular to and passing through said desired path of movement of said beam.
Claim 3
Dependent Claim
19 words
Apparatus according to claim 1, wherein said modulating means is adapted to sinusoidally modulate the amplitude of said beam.
Claim 4
Dependent Claim
18 words
Apparatus according to claim 2, wherein said modulating means is adapted to substantially 100% amplitude modulate said beam.
Claim 5
Dependent Claim
12 words
Apparatus according to claim 1, including means for displaying said position signals.
Claim 6
Dependent Claim
36 words
Apparatus according to claim 1, including means for altering the path of movement of said beam, said means being connected to receive said position signals to correct any deviation of said beam from said desired path.
Claim 7
Dependent Claim
35 words
Apparatus according to claim 1, including means for summing said output signals to provide a further signal which is proportional to the beam current regardless of any deviation of said beam from said desired path.
Claim 8
Dependent Claim
25 words
Apparatus according to claim 6, including an integrator connected to receive said further signal from said summing means to integrate the further signal with time.
Claim 9
Dependent Claim
62 words
Apparatus according to claim 1, wherein said detector means is adapted to provide four said output signals and said means for comparing comprises first and second subtraction circuits each adapted to subtract output signals from a respective pair of the output signals proportional to the modulation of the magnetic field at opposed positions, each subtraction circuit providing one of said position signals.
Claim 10
Dependent Claim
38 words
Apparatus according to claim 1, wherein said detector means comprises a plurality of separate coils, one for providing each said output signal, said coils co-operating to form a multi-section toroid coaxial with said desired path of said beam.
Claim 11
Dependent Claim
36 words
Apparatus according to claim 1, wherein said detector means comprises a plurality of separate toroidal coils, one for providing each said output signal, spaced apart along and each coaxial with said desired path of said beam.
Claim 12
Dependent Claim
15 words
Apparatus according to claim 1, including a source adapted to supply a focussed ion beam.
Claim 13
Independent Claim
129 words
A method of monitoring the current comprised by a beam of charged particles, comprising modulating the amplitude of said beam to thereby correspondingly modulate the strength of the magnetic field of said beam, detecting the modulation of the strength of said magnetic field to provide at least three output signals each corresponding to the modulation of the strength of said magnetic field of the beam at a respective one of a plurality of positions equally spaced around a desired path of said beam, and comparing and developing from said at least three output signals a pair of position signals each indicating the position of said beam along a respective one of a pair of orthogonal axes perpendicular to and passing through said desired path of movement of said beam.
Claim 14
Independent Claim
129 words
A method of monitoring the current comprised by a beam of charged particles, comprising modulating the amplitude of said beam to thereby correspondingly modulate the strength of the magnetic field of said beam, detecting the modulation of the strength of said magnetic field to provide at least three output signals each corresponding to the modulation of the strength of said magnetic field of the beam at a respective one of a plurality of positions equally spaced around a desired path of said beam, and comparing and developing from said at least three output signals a pair of position signals each indicating the position of said beam along a respective one of a pair of orthogonal axes perpendicular to and passing through said desired path of movement of said beam.
Claim 15
Dependent Claim
15 words
A method according to claim 12, wherein the amplitude of the beam is modulated sinusoidally.
Claim 16
Dependent Claim
13 words
A method according to claim 13, wherein the beam is substantially 100% modulated.
Claim 17
Dependent Claim
34 words
A method according to claim 12, including summing said output signals to provide a further signal which is proportional to said beam current regardless of any deviation of the beam from said desired path.
Claim 18
Dependent Claim
13 words
A method according to claim 15, including integrating said further signal with time.
Claim 19
Dependent Claim
11 words
A method according to claim 12, including displaying said position signals.
Claim 20
Dependent Claim
28 words
A method according to claim 12, including altering the path of movement of said beam to correct any deviation from said desired path indicated by said position signals.
Claim 21
Dependent Claim
44 words
A method according to claim 12, wherein four said output signals are deTected and said comparing step comprises subtracting from each of two of the output signals the output signal derived from the opposed position to provide two difference signals comprising said position signals.
Claim 22
Dependent Claim
14 words
A method according to claim 12, wherein said beam is a focussed ion beam.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |