Patent US3801792A successfully refreshed from Google Patents.
US3801792A
Expired / Lapsed
US
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Electron beam apparatus
Assignee: AT&T Inc
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Filing: 1973-05-23
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Granted: 1974-04-02
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Expires: 1993-05-23
Abstract
Abstract Various components of a conventional electron beam apparatus are modified to achieve precise high-speed deflection and blanking of the electron beam. The modified apparatus is designed to be included, for example in a high-resolution automated electron beam exposure system for integrated-circuit fabrication.
Inventors
- 👤 L Lin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:18
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J37/00; H01J37/30; H01J37/3002; H01J37/3007
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
239 words
In combination in an electron beam apparatus, a source of a beam of electrons, means including a plurality of successive lenses for successively demagnifying said source, each of said lenses having a crossover point respectively associated therewith, means for deflecting said beam to any specified point on a work surface that includes the crossover point associated with the last one of said successive lenses, aperture means interposed between said source and said work surface, electrostatic beam blanking means interposed between said source and said aperture means and centered with respect to a crossover point for causing said beam to be directed through an aperture in said aperture means and at said work surface when no blanking potential is applied to said blanking means and to be deflected to be blocked by said aperture means when a blanking potential is applied to said blanking means, said deflecting means comprising deflection coils positioned between one of said successive lenses and an adjacent portion of the path traversed by said electron beam, a cylindrical ferrite shield interposed between said coils and said one lens, and a cylindrical screening tube interposed between said deflection coils and an adjacent portion of the path traversed by said electron beam, said tube comprising a dielectric cylinder having coated on the inner surface thereof a conductive layer whose thickness is substantially less than the skin depth of the metal at the desired bandwidth of the deflecting means.
Claim 2
Dependent Claim
239 words
In combination in an electron beam apparatus, a source of a beam of electrons, means including a plurality of successive lenses for successively demagnifying said source, each of said lenses having a crossover point respectively associated therewith, means for deflecting said beam to any specified point on a work surface that includes the crossover point associated with the last one of said successive lenses, aperture means interposed between said source and said work surface, electrostatic beam blanking means interposed between said source and said aperture means and centered with respect to a crossover point for causing said beam to be directed through an aperture in said aperture means and at said work surface when no blanking potential is applied to said blanking means and to be deflected to be blocked by said aperture means when a blanking potential is applied to said blanking means, said deflecting means comprising deflection coils positioned between one of said successive lenses and an adjacent portion of the path traversed by said electron beam, a cylindrical ferrite shield interposed between said coils and said one lens, and a cylindrical screening tube interposed between said deflection coils and an adjacent portion of the path traversed by said electron beam, said tube comprising a dielectric cylinder having coated on the inner surface thereof a conductive layer whose thickness is substantially less than the skin depth of the metal at the desired bandwidth of the deflecting means.
Claim 3
Dependent Claim
61 words
A combination as in claim 1 wherein the last one of said successive lenses includes a circular opening through which the electron beam is directed at said work surface, and further including an additional coil positioned adjacent to a portion of the path traversed by said electron beam for centering said beam with respect to said opening in said last lens.
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) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |