US4463255A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for enhanced neutralization of positively charged ion beam
Assignee: Varian Semiconductor Equipment Associates Inc
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Filing: 1982-12-20
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Granted: 1984-07-31
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Expires: 2002-12-20
Abstract
Abstract An apparatus for the enhanced neutralization of a positively charged particle beam has a source of primary electrons which are directed at a dummy target positioned adjacent the ion beam. The secondary electrons have a low energy and are susceptible to being entrapped within the volume of the positively charged beam. The ion beam attracts these low energy electrons until effective beam neutralization is achieved. The ions in the beam are individually neutralized when the beam strikes the target.
Inventors
- 👤 David A. Robertson
- 👤 Norman L. Turner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:56
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/30; H01J37/317; H01J37/3171; H01J2237/00; H01J2237/004; H01J2237/0041
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
111 words
An apparatus for enhanced neutralization of a beam of positive ions in an ion implantation system, comprising: an electron source for generating a primary electron beam; and means responsive to said primary electron beam for providing controllable secondary electron emission independently of said beam of positive ions, said secondary electron emission means comprising a dummy target for emitting secondary electrons having lower energies than said primary electron beam when stimulated by bombardment by said primary electron beam, said dummy target being positioned adjacent to but not in the path of said beam of positive ions within said system to permit said secondary electrons to be entrapped within said positive ion beam.
Claim 2
Independent Claim
111 words
An apparatus for enhanced neutralization of a beam of positive ions in an ion implantation system, comprising: an electron source for generating a primary electron beam; and means responsive to said primary electron beam for providing controllable secondary electron emission independently of said beam of positive ions, said secondary electron emission means comprising a dummy target for emitting secondary electrons having lower energies than said primary electron beam when stimulated by bombardment by said primary electron beam, said dummy target being positioned adjacent to but not in the path of said beam of positive ions within said system to permit said secondary electrons to be entrapped within said positive ion beam.
Claim 3
Dependent Claim
26 words
The apparatus of claim 1 wherein said primary electron beam generated by said electron source passes through said positive ion beam before striking said dummy target.
Claim 4
Dependent Claim
41 words
The apparatus of claim 1 wherein the kinetic energy of the electrons in said primary electron beam is selected to be at least as great as the energy required to produce the maximum yield of secondary electrons from said dummy target.
Claim 5
Dependent Claim
18 words
The apparatus of claim 1 wherein the secondary electron yield from said dummy target is at least one.
Claim 6
Dependent Claim
14 words
The apparatus of claim 4 wherein said dummy target is composed of a metal.
Claim 7
Dependent Claim
14 words
The apparatus of claim 5 wherein said metal of said dummy target is aluminum.
Claim 8
Dependent Claim
36 words
The apparatus of claim 1 wherein said electron source comprises a: a filament; an electrical power source for heating said filament; and a reflector shield disposed to reflect electrons in the direction of said dummy target.
Claim 9
Dependent Claim
25 words
The apparatus of claim 7 wherein said electrical power source regulates the amount and the average kinetic energy of electrons emitted from said electron source.
Claim 10
Dependent Claim
11 words
The apparatus of claim 8 wherein said filament describes a helix.
Claim 11
Dependent Claim
17 words
The apparatus of claim 1 wherein most of said secondary electrons have energies less than 100 eV.
Claim 12
Independent Claim
82 words
A method of enhanced neutralization of a beam of positive ions in an ion implantation system, comprising the steps of: generating a primary electron beam; providing controllable secondary electron emission independently of said beam of positive ions by directing said primary electron beam at a dummy target positioned adjacent to said beam of positive ions, thereby causing secondary electrons having lower energies than said primary electron beam to be emitted from said dummy target and entrapped within said beam of positive ions.
Claim 13
Independent Claim
82 words
A method of enhanced neutralization of a beam of positive ions in an ion implantation system, comprising the steps of: generating a primary electron beam; providing controllable secondary electron emission independently of said beam of positive ions by directing said primary electron beam at a dummy target positioned adjacent to said beam of positive ions, thereby causing secondary electrons having lower energies than said primary electron beam to be emitted from said dummy target and entrapped within said beam of positive ions.
Claim 14
Dependent Claim
30 words
A method of claim 11 wherein said step of providing controllable secondary electron emission includes directing said primary electron beam through said beam of positive ions to said dummy target.
Claim 15
Dependent Claim
43 words
A method as defined in claim 11 further including the steps of controlling the current in said beam of positive ions and varying said secondary electron emission in accordance with said ion beam current to provide neutralization of said beam of positive ions.
Claim 16
Dependent Claim
114 words
In apparatus for neutralization of a beam of positive ions in an ion implantation system, said apparatus including an electron source for generating a primary electron beam, the improvement comprising: means responsive to said primary electron beam for providing controllable secondary electron emission independently of said beam of positive ions, said secondary electron emission means comprising a dummy target for emitting secondary electrons when stimulated by bombardment by said primary electron beam, said secondary electrons having lower energies than said primary electron beam, said dummy target being positioned adjacent to but not in the path of said beam of positive ions to permit said secondary electrons to be entrapped within said positive ion beam.
Claim 17
Dependent Claim
114 words
In apparatus for neutralization of a beam of positive ions in an ion implantation system, said apparatus including an electron source for generating a primary electron beam, the improvement comprising: means responsive to said primary electron beam for providing controllable secondary electron emission independently of said beam of positive ions, said secondary electron emission means comprising a dummy target for emitting secondary electrons when stimulated by bombardment by said primary electron beam, said secondary electrons having lower energies than said primary electron beam, said dummy target being positioned adjacent to but not in the path of said beam of positive ions to permit said secondary electrons to be entrapped within said positive ion beam.
Claim 18
Dependent Claim
19 words
The improvement as defined in claim 14 wherein most of said secondary electrons have energies less than 100 eV.
Claim 19
Dependent Claim
103 words
Ion implanatation apparatus comprising: means for generating a beam of positive ions; an electron source for generating a primary electron beam; and means responsive to said primary electron beam for providing controllable secondary electron emission independently of said beam of positive ions, said secondary electron emission means comprising a dummy target for emitting secondary electrons having lower energies than said primary electron beam when stimulated by bombardment by said primary electron beam, said dummy target being positioned adjacent to but not in the path of said beam of positive ions to permit said secondary electrons to be entrapped within said positive ion beam.
Claim 20
Dependent Claim
103 words
Ion implanatation apparatus comprising: means for generating a beam of positive ions; an electron source for generating a primary electron beam; and means responsive to said primary electron beam for providing controllable secondary electron emission independently of said beam of positive ions, said secondary electron emission means comprising a dummy target for emitting secondary electrons having lower energies than said primary electron beam when stimulated by bombardment by said primary electron beam, said dummy target being positioned adjacent to but not in the path of said beam of positive ions to permit said secondary electrons to be entrapped within said positive ion beam.
Claim 21
Dependent Claim
23 words
The apparatus as defined in claim 16 wherein said primary electron beam passes through said positive ion beam before striking said dummy target.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-31 | 1988-01-30 | 1988-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-31 | 1992-01-30 | 1992-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-31 | 1996-01-30 | 1996-07-31 | $7700.00 | Window Closed / Lapsed |