US4430570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron beam exposing apparatus
Assignee: Toshiba Corp
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Filing: 1980-12-04
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Granted: 1984-02-07
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Expires: 2000-12-04
Abstract
Abstract A variable shaping type electron beam exposing apparatus is provided which comprises an electron gun which irradiates an electron beam from the front end of a cathode chip; shaping plates having openings of variable shapes for shaping the electron beam irradiated from the electron gun into the shapes of these openings; and an objective lens for focusing the electron beam passed through the shaping plates into a predetermined shape on a sample. In this apparatus, the cathode chip is made of single-crystal lanthanum hexaboride whose axial orientation is <310>, the front end of it is formed into a circular conical shape, and half the vertical angle of the front end is set to be between 60° and 85°. The maximum area of the image on the sample is between 2 to 50 μm 2 .
Inventors
- 👤 Tadahiro Takigawa
- 👤 Isao Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:13
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/15; H01J1/16; H01J1/14; H01J1/148; H01J3/00; H01J3/02; H01J3/021; H01J37/00; H01J37/02; H01J37/04; H01J37/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
153 words
An electron beam exposing apparatus comprising: an electron gun having a cathode which is made of a single-crystal lanthanum hexaboride and which is shaped into a cone with half the vertical angle being between 60° and 85° such that the spread of the electron beam is kept below a predetermined value, that the luminous intensity of the electron beam is increased while still keeping said spread below said predetermined value and that the current density in a variably shaped aperture is kept uniform; means for heating said cathode at a given temperature to irradiate an electron beam of which a crossover image and an emission pattern are circular; means, including openings of variable shape, for shaping the electron beam irradiated from said cathode into the shapes of the openings; and means for focusing the shaped beam to form a beam spot having an area of 2 to 50 μm 2 on a sample.
Claim 2
Dependent Claim
153 words
An electron beam exposing apparatus comprising: an electron gun having a cathode which is made of a single-crystal lanthanum hexaboride and which is shaped into a cone with half the vertical angle being between 60° and 85° such that the spread of the electron beam is kept below a predetermined value, that the luminous intensity of the electron beam is increased while still keeping said spread below said predetermined value and that the current density in a variably shaped aperture is kept uniform; means for heating said cathode at a given temperature to irradiate an electron beam of which a crossover image and an emission pattern are circular; means, including openings of variable shape, for shaping the electron beam irradiated from said cathode into the shapes of the openings; and means for focusing the shaped beam to form a beam spot having an area of 2 to 50 μm 2 on a sample.
Claim 3
Dependent Claim
19 words
An electron beam exposing apparatus according to claim 1, wherein the axis of said cathode is oriented toward <100>.
Claim 4
Dependent Claim
23 words
An electron beam exposing apparatus according to claim 1, in which said cathode is made of a single-crystal lanthanum hexaboride with an impurity.
Claim 5
Dependent Claim
19 words
An electron beam exposing apparatus according to claim 1, in which said cathode is shaped into a circular cone.
Claim 6
Dependent Claim
19 words
An electron beam exposing apparatus according to claim 1, in which said cathode is shaped into a pyramidal cone.
Claim 7
Dependent Claim
19 words
An electron beam exposing apparatus according to claim 1, wherein the axis of said cathode is oriented toward <310>.
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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) | 1987-02-06 | 1987-08-08 | 1988-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-06 | 1991-08-08 | 1992-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-06 | 1995-08-08 | 1996-02-07 | $7700.00 | Window Closed / Lapsed |