US4950377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for reactive ion etching
Assignee: Siemens AG
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Filing: 1989-08-03
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Granted: 1990-08-21
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Expires: 2009-08-03
Abstract
Abstract The apparatus includes a means for generating a magnetic field at a first electrode to which a high frequency voltage is applied and includes a generator for generating a rectangular low frequency voltage that is capacitively coupled to a second electrode which carries the substrate to be etched. The low frequency voltage comprises a negative half-wave having a short duration and a positive half-wave. The duration of the negative half-wave is selected to be shorter than a time constant for charging the substrate after a potential change corresponding to the amplitude of the half-wave and the positive half-wave is dimensioned so that the substrate remains free of charges on the average.
Inventors
- 👤 Holger Huebner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:11
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32082; H01J37/32137; H01J37/32146; H01J2237/00; H01J2237/004; H01J2237/0041; H01J2237/0044; H01J2237/32; H01J2237/33; H01J2237/334; H01J2237/3341
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
120 words
An apparatus for reactive ion etching of a substrate, comprising: two electrodes arranged at a distance from one another; means for applying a high frequency voltage to a first of said two electrodes to generate a high frequency plasma between said two electrodes; a second of said two electrodes being adapted to receive a substrate to be etched, the substrate having a charging time constant; a generator for generating a low-frequency voltage having a negative signal portion of shorter duration than the charging time constant of the substrate and having a positive signal portion of a dimension so that the substrate has a non-positive average charge during etching; and means for capacitively coupling said low-frequency voltage to said second electrode.
Claim 2
Independent Claim
120 words
An apparatus for reactive ion etching of a substrate, comprising: two electrodes arranged at a distance from one another; means for applying a high frequency voltage to a first of said two electrodes to generate a high frequency plasma between said two electrodes; a second of said two electrodes being adapted to receive a substrate to be etched, the substrate having a charging time constant; a generator for generating a low-frequency voltage having a negative signal portion of shorter duration than the charging time constant of the substrate and having a positive signal portion of a dimension so that the substrate has a non-positive average charge during etching; and means for capacitively coupling said low-frequency voltage to said second electrode.
Claim 3
Dependent Claim
18 words
An apparatus as claimed in claim 1, wherein said generator generates a square-wave signal as said low frequency
Claim 4
Independent Claim
33 words
An apparatus as claimed in claim comprising: a control means for controlling said low frequency voltage of said generator by setting said negative and positive signal portions to achieve a predetermined rated potential.
Claim 5
Dependent Claim
14 words
An apparatus as claimed in claim 3, wherein said predetermined rated potential is ground.
Claim 6
Dependent Claim
22 words
An apparatus as claimed in claim 4, wherein said control means includes means for controlling an amplitude of said negative signal portion
Claim 7
Dependent Claim
58 words
An apparatus as claimed in claim 1, further comprising: means for generating a magnetic field in a region between said two electrodes, said magnetic field having a field strength which decreases in a direction from one of said two electrodes to another of said two electrodes and said magnetic field having field lines proceeding transverse to said direction.
Claim 8
Dependent Claim
35 words
An apparatus as claimed in claim 6, wherein said means for generating a magnetic field comprises two permanent magnet bars arranged at a distance from one another and arranged at one of said two electrodes.
Claim 9
Dependent Claim
16 words
An apparatus as claimed in claim 1, wherein said negative and positive signal portions are half-waves.
Claim 10
Independent Claim
105 words
A method for reactive ion etching of a substrate, comprising the steps of: generating a high frequency plasma between two electrodes by applying a high frequency voltage to one of said electrodes; arranging a substrate to be etched at another of said two electrodes; applying a low frequency voltage to said another of said two electrodes, said low frequency voltage having a negative wave portion of a shorter duration than a charging time constant for electrical charging of the substrate, said low frequency voltage having a positive wave portion of such dimension that the substrate remains free of charges on average or remains negatively charged.
Claim 11
Independent Claim
105 words
A method for reactive ion etching of a substrate, comprising the steps of: generating a high frequency plasma between two electrodes by applying a high frequency voltage to one of said electrodes; arranging a substrate to be etched at another of said two electrodes; applying a low frequency voltage to said another of said two electrodes, said low frequency voltage having a negative wave portion of a shorter duration than a charging time constant for electrical charging of the substrate, said low frequency voltage having a positive wave portion of such dimension that the substrate remains free of charges on average or remains negatively charged.
Claim 12
Dependent Claim
22 words
A method as claimed in claim 9, wherein said positive wave portion is dimensioned in duration to achieve a non-positive average charge.
Claim 13
Dependent Claim
22 words
A method as claimed in claim 9, wherein said positive wave portion is dimensioned in amplitude to achieve a nonpositive average charge.
Claim 14
Independent Claim
173 words
An apparatus for reactive ion etching of a substrate, comprising: a housing filled with a process gas; first and second electrodes arranged in said housing at a distance from one another, a substrate to be etched being arranged on said second electrode; a high frequency generator having an output connected to said first electrode to apply a high frequency signal to said first electrode for generating a high frequency plasma; a low frequency generator having an output co to said second electrode to apply a low frequency signal to said second electrode, said low frequency signal being a generally rectangular voltage with a negative signal portion of a duration less than a charging time constant of the substrate on said second electrode and a positive signal portion of a dimension to at least cancel any charging of the substrate by the negative signal portion; and means for generating a magnetic field between said first and second electrodes with magnetic field lies extending transversely relative to a direction between said first and second electrodes.
Claim 15
Independent Claim
173 words
An apparatus for reactive ion etching of a substrate, comprising: a housing filled with a process gas; first and second electrodes arranged in said housing at a distance from one another, a substrate to be etched being arranged on said second electrode; a high frequency generator having an output connected to said first electrode to apply a high frequency signal to said first electrode for generating a high frequency plasma; a low frequency generator having an output co to said second electrode to apply a low frequency signal to said second electrode, said low frequency signal being a generally rectangular voltage with a negative signal portion of a duration less than a charging time constant of the substrate on said second electrode and a positive signal portion of a dimension to at least cancel any charging of the substrate by the negative signal portion; and means for generating a magnetic field between said first and second electrodes with magnetic field lies extending transversely relative to a direction between said first and second electrodes.
Claim 16
Dependent Claim
38 words
An apparatus as claimed in claim 12, wherein said means for generating a magnetic field includes two permanent bar magnets arranged at a distance from one another and being arranged on one of said first and second electrodes.
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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) | 1993-08-20 | 1994-02-19 | 1994-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-20 | 1998-02-19 | 1998-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-20 | 2002-02-19 | 2002-08-21 | $7700.00 | Window Closed / Lapsed |