US5389858A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable axis stigmator
Assignee: International Business Machines Corp
•
Filing: 1992-07-16
•
Granted: 1995-02-14
•
Expires: 2012-07-16
Abstract
Abstract The magnetic axis of a stigmation yoke is varied from the mechanical axis of the stigmation yoke by differentially driving pairs of coils in a quadrupole configuration with currents which differ from a nominal stigmation current by approximately equal amounts, applied in opposite senses. Set-up procedures for electron beam deflection systems, such as in e-beam tools, are automated by emulating manual procedures in combination with electrical alteration of the magnetic axis of the stigmator yoke. Stigmation errors can also be corrected under automated set-up procedure control to allow dynamic correction of astigmatism in electron beam deflection system. Electrically variability of the magnetic axis of the stigmator yoke also allows the placement of the stigmator yoke at a position in the electron optical column other than prior to deflection stages as well as improved freedom from positional and aberrational errors.
Inventors
- 👤 Guenther O. Langner
- 👤 Paul F. Petric
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:13
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/10; H01J37/14; H01J37/141; H01J37/153; H01J37/30; H01J37/3002; H01J37/3007
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
157 words
An arrangement for shifting the axis of a quadrupole field including a yoke having at least four coils arranged in pairs in a quadrupole configuration wherein at least the coils of at least one said pair of coils are individually electrically accessible, means for individually driving said coils of said at least one pair of coils including means for individually deriving current values for each coil of said at least one pair of coils in accordance with a position to which said axis is to be shifted, and means for controlling said means for individually driving said coils of said at least one pair of coils for differentially altering current in respective ones of said at least one pair of coils by approximately the same amount, wherein said amount is approximately a linear function of one of two orthogonal components of a distance of a magnetic axis of said yoke from a mechanical axis of said yoke.
Claim 2
Dependent Claim
157 words
An arrangement for shifting the axis of a quadrupole field including a yoke having at least four coils arranged in pairs in a quadrupole configuration wherein at least the coils of at least one said pair of coils are individually electrically accessible, means for individually driving said coils of said at least one pair of coils including means for individually deriving current values for each coil of said at least one pair of coils in accordance with a position to which said axis is to be shifted, and means for controlling said means for individually driving said coils of said at least one pair of coils for differentially altering current in respective ones of said at least one pair of coils by approximately the same amount, wherein said amount is approximately a linear function of one of two orthogonal components of a distance of a magnetic axis of said yoke from a mechanical axis of said yoke.
Claim 3
Dependent Claim
19 words
An arrangement as recited in claim 1, further including means for altering current in all coils of said yoke.
Claim 4
Dependent Claim
21 words
An arrangement as recited in claim 2, wherein said yoke comprises an astigmatism correction arrangement for an electron beam deflection system.
Claim 5
Dependent Claim
38 words
An arrangement as recited in claim 3, further including means for detecting electron beam deflection when said current in all coils of said yoke is altered by said means for altering current in all coils of said yoke.
Claim 6
Dependent Claim
33 words
A arrangement as recited in claim 4, wherein said means for individually driving said coils of said at least one pair of coils is responsive to said means for detecting electron beam deflection.
Claim 7
Dependent Claim
29 words
A correction arrangement as recited in claim 5, wherein said means for altering current in all coils of said yoke is responsive to programmed control of set-up automation means.
Claim 8
Dependent Claim
39 words
A correction arrangement as recited in claim 6, wherein said means for individually driving said coils of said at least one pair of coils is responsive to said means for detecting electron beam deflection and said set-up automation means.
Claim 9
Dependent Claim
14 words
A correction arrangement as recited in claim 7, further including dynamic stigmatism correction means.
Claim 10
Dependent Claim
22 words
An arrangement as recited in claim 1, wherein said yoke comprises an astigmatism correction arrangement for a charged particle beam deflection system.
Claim 11
Independent Claim
177 words
A method of shifting a magnetic axis of a yoke from the position of a mechanical axis of said stigmator yoke, said yoke having at least four coils arranged in pairs in a quadrupole configuration wherein at least the coils of at least one said pair of coils are individually electrically accessible, said method including the steps of individually deriving driving currents for each of said coils of said at least one pair of coils in accordance with a position to which said magnetic axis is to be shifted, individually driving said coils of said at least one pair of coils with said currents individually derived by said deriving step, and controlling said individual driving of said coils of said at least one pair of coils for differentially altering current in respective ones of said at least one pair of coils by approximately the same amount, wherein said amount is approximately a linear function of one of two orthogonal components of a distance of a magnetic axis of said yoke from a mechanical axis of said yoke.
Claim 12
Independent Claim
177 words
A method of shifting a magnetic axis of a yoke from the position of a mechanical axis of said stigmator yoke, said yoke having at least four coils arranged in pairs in a quadrupole configuration wherein at least the coils of at least one said pair of coils are individually electrically accessible, said method including the steps of individually deriving driving currents for each of said coils of said at least one pair of coils in accordance with a position to which said magnetic axis is to be shifted, individually driving said coils of said at least one pair of coils with said currents individually derived by said deriving step, and controlling said individual driving of said coils of said at least one pair of coils for differentially altering current in respective ones of said at least one pair of coils by approximately the same amount, wherein said amount is approximately a linear function of one of two orthogonal components of a distance of a magnetic axis of said yoke from a mechanical axis of said yoke.
References Cited (Backward Citations)
US2919381A
Cited
US3152238A
Cited
US3597608A
Cited
US4214163A
Cited
US4567369A
Cited
US4859857A
Cited
US4791295A
Cited
US4902940A
Cited
US4962309A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-13 | 1998-08-15 | 1999-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-13 | 2002-08-15 | 2003-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-13 | 2006-08-15 | 2007-02-14 | $7700.00 | Window Closed / Lapsed |