US4539835A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Calibration apparatus for capacitance height gauges
Assignee: SK Hynix Inc
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Filing: 1984-03-14
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Granted: 1985-09-10
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Expires: 2004-03-14
Abstract
Abstract In an electron beam lithography apparatus a capacitance height gauge is used to determine the distance between a reticule and electron optics. In order to calibrate the capacitance gauge an optical interferometer, including a mirror are mounted on the same axis as the capacitance gauge. The mirror is moved a predetermined distance so that the movement distance measured by the capacitance gauge and the interferometer can be compared.
Inventors
- 👤 John R. Shambroom
- 👤 Alan P. Sliski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:36
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7049; G03F9/7053; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/08; G01B7/082; G01B7/14; H; H01; H01J; H01J37/00; H01J37/30; H01J37/304
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
136 words
An apparatus for calibrating a capacitance height gauge having a capacitive sensor, comprising: a base; a laser interferometer assembly supported by said base; an electrically conductive mirror movably supported on said base opposite to said laser assembly; a means for supporting said capacitance gauge with said sensor oppositely disposed with respect to said mirror; and a means for moving said mirror with respect to said laser interferometer, wherein said moving means positions said mirror a desired location from said sensor such that said sensor forms a capacitor with said mirror, and wherein said laser interferometer assembly is utilized to determine the distance between said sensor and said mirror, further comprising a means for obtaining an electrical reading from said capacitor comprised of said sensor and said mirror while said mirror is positioned at said desired location.
Claim 2
Independent Claim
136 words
An apparatus for calibrating a capacitance height gauge having a capacitive sensor, comprising: a base; a laser interferometer assembly supported by said base; an electrically conductive mirror movably supported on said base opposite to said laser assembly; a means for supporting said capacitance gauge with said sensor oppositely disposed with respect to said mirror; and a means for moving said mirror with respect to said laser interferometer, wherein said moving means positions said mirror a desired location from said sensor such that said sensor forms a capacitor with said mirror, and wherein said laser interferometer assembly is utilized to determine the distance between said sensor and said mirror, further comprising a means for obtaining an electrical reading from said capacitor comprised of said sensor and said mirror while said mirror is positioned at said desired location.
Claim 3
Dependent Claim
69 words
The apparatus of claim 1, further comprising a computer control system, and wherein said laser interferometer assembly includes a laser electronics circuit, said computer control system indicating to said laser electronics circuit a desired position for said mirror, and said laser electronics circuits, in response thereto, generating an error signal representative of the differential distance between the actual position of said mirror and said desired position of said mirror.
Claim 4
Dependent Claim
41 words
The apparatus of claim 2, further comprising a calibration fixture electronics circuit, said calibration fixture electronics circuit controlling said moving means in response to said error signal generated by said laser electronics circuit to move said mirror to said desired location.
Claim 5
Dependent Claim
86 words
The apparatus of claim 3, wherein said laser interferometer assembly also includes a laser, an interferometer cube, and a laser receiver, said laser emitting a laser beam through said interferometer cube to said mirror, said laser beam being reflected off of said mirror to said laser receiver, said laser being controlled by said laser electronics circuit, said laser receiver providing an input to said laser electronics circuit indicating the distance to said mirror, said laser electronics circuits utilizing said distance input to generate said error signal.
Claim 6
Dependent Claim
50 words
The apparatus of claim 3 further comprising a means for sensing the velocity of said mirror, said velocity sensing means providing an input to said calibration fixture electronics circuit, said calibration fixture electronics circuit processing said mirror velocity input to provide damping of said mirror movement by said moving means.
Claim 7
Dependent Claim
22 words
The apparatus of claim 5 wherein said calibration fixture electronics circuit further comprises a position gain circuit and a velocity gain circuit.
Claim 8
Dependent Claim
40 words
The apparatus of claim 6 wherein the output of said position gain circuit is combined with the output of said velocity gain circuit to damp the movement of said mirror to prevent oscillation of said mirror about said desired point.
Claim 9
Dependent Claim
65 words
The apparatus of claim 3 wherein said error signal includes an indication of the polarity of said error signal, and wherein said calibration fixture electronics includes a means for processing said polarity indication to apply the proper polarity to said error signal before said error signal is applied to said moving means to ensure that said moving means moves said mirror towards said desired location.
Claim 10
Dependent Claim
45 words
The apparatus of claim 3 wherein said moving means comprises a shaft supported in an air bearing, said mirror being mounted at one end of said shaft, said moving means including means to move said shaft and said mirror in response to said error signal.
Claim 11
Dependent Claim
67 words
The apparatus of claim 9 wherein a drive magnet is rigidly secured to said shaft, and a stationary drive coil encircles said shaft proximate to said drive magnet, said calibration fixture electronics processing said error signal to provide a drive signal of the proper polarity to said drive coil to either repel or attract said drive magnet in order to drive said mirror to said desired location.
Claim 12
Dependent Claim
98 words
The apparatus of claim 10 further comprising a velocity damping magnet rigidly secured to said shaft, and a stationary velocity sensing coil encircling said shaft proximate to said velocity damping magnet, a voltage being generated across said velocity sensing coil as said velocity damping magnet is moved with respect to said velocity damping coil, said voltage comprising a velocity damping signal, said velocity damping signal being input to said calibration fixture electronics, said calibration fixture electronics processing said velocity damping signal to damp the movement of said mirror to prevent oscillation of said mirror about said desired location.
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) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |