Patent US4701620A successfully refreshed from Google Patents.
US4701620A
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US
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Electron beam exposure apparatus
Assignee: Hitachi Ltd
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Filing: 1986-08-05
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Granted: 1987-10-20
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Expires: 2006-08-05
Abstract
Abstract Disclosed is an electron beam exposure apparatus which includes an objective lens focusing an electron beam, and a dynamic focus correction lens dynamically correcting the focusing by the objective lens. The apparatus comprises a control circuit which, in order to prevent a current variation induced in the objective lens by the dynamic focus correction lens, controls current supplied to the objective lens so as to cancel the current variation induced in the objective lens due to the coil current of the dynamic focus correction lens.
Inventors
- 👤 Masahide Okumura
- 👤 Takashi Matsuzaka
- 👤 Genya Matsuoka
- 👤 Norio Saitou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:19
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/153; H01J37/30; H01J37/304
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
71 words
An electron beam exposure apparatus comprising means for emitting an electron beam, an objective lens focusing the electron beam, a dynamic focus correction lens, located within said objective lens which dynamically corrects the focusing by said objective lens, and control means for controlling current supplied to said objective lens so as to cancel a current variation induced in said objective lens due to coil current of said dynamic focus correction lens.
Claim 2
Dependent Claim
71 words
An electron beam exposure apparatus comprising means for emitting an electron beam, an objective lens focusing the electron beam, a dynamic focus correction lens, located within said objective lens which dynamically corrects the focusing by said objective lens, and control means for controlling current supplied to said objective lens so as to cancel a current variation induced in said objective lens due to coil current of said dynamic focus correction lens.
Claim 3
Dependent Claim
54 words
An electron beam exposure apparatus as claimed in claim 1, wherein said control means includes current detecting means for detecting the coil current of said dynamic focus correction lens, and said control means controlling the current supplied to said objective lens on the basis of the current value detected by said current detecting means.
Claim 4
Dependent Claim
57 words
An electron beam exposure apparatus as claimed in claim 1, wherein said control means includes a detecting coil detecting a variation of the intensity of the magnetic field of said objective lens, and said control means controlling the current supplied to said objective lens on the basis of the detection output signal appearing from said detecting 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) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |