US4400235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etching apparatus and method
Assignee: Agere Systems LLC
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Filing: 1982-03-25
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Granted: 1983-08-23
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Expires: 2002-03-25
Abstract
Abstract In a plasma-assisted dry etching process designed to pattern VLSI devices, a relatively high and uniform etch rate exhibiting low contamination is achieved over the entire surface extent of each wafer to be etched. This is accomplished by mounting the wafers in a unique fashion on one of two spaced-apart electrodes in the reaction chamber of a dry etching system. In particular, the front surface of each wafer is maintained in substantially the same plane as that of surrounding dielectric material. Additionally, the thickness of the surrounding dielectric material is designed to be considerably greater than the thickness of any dielectric material in contact with the back surface of each wafer. In that way, the entire front surface extent of each wafer is influenced by a relatively uniform electric field. Moreover, the available field in the chamber is in effect focussed onto the wafer surfaces, thereby achieving a relatively high etch rate characterized by low contamination.
Inventors
- 👤 Gerald A. Coquin
- 👤 Joseph M. Moran
- 👤 Gary N. Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:01
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/70; H10P72/76; H10P72/7604; H10P72/7621
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
190 words
Apparatus for etching the front surfaces of workpieces, said apparatus comprising a reaction chamber having spaced-apart conductive electrodes therein, means for establishing an electric field between said electrodes, means for introducing a gas into said chamber into the space between said electrodes, and means for mounting said workpieces on one of said electrodes to establish a substantially uniform and focussed electric field across the surfaces of said workpieces during etching, wherein said one electrode includes post regions disposed in respective alignment with said workpieces to be etched, and wherein a dielectric member formed to surround the sides of said post regions is positioned on said one electrode to cover all but the post regions of said one electrode with a relatively thick layer of dielectric material, said member having a main planar surface and being formed to permit said workpieces to be respectively mounted in alignment with said post regions with the front surfaces of said workpieces in the same plane as that of said main surface and with the thickness of any dielectric material interposed between the back surfaces of said workpieces and said post regions being relatively thin.
Claim 2
Dependent Claim
190 words
Apparatus for etching the front surfaces of workpieces, said apparatus comprising a reaction chamber having spaced-apart conductive electrodes therein, means for establishing an electric field between said electrodes, means for introducing a gas into said chamber into the space between said electrodes, and means for mounting said workpieces on one of said electrodes to establish a substantially uniform and focussed electric field across the surfaces of said workpieces during etching, wherein said one electrode includes post regions disposed in respective alignment with said workpieces to be etched, and wherein a dielectric member formed to surround the sides of said post regions is positioned on said one electrode to cover all but the post regions of said one electrode with a relatively thick layer of dielectric material, said member having a main planar surface and being formed to permit said workpieces to be respectively mounted in alignment with said post regions with the front surfaces of said workpieces in the same plane as that of said main surface and with the thickness of any dielectric material interposed between the back surfaces of said workpieces and said post regions being relatively thin.
Claim 3
Dependent Claim
34 words
Apparatus as in claim 1 wherein the area of said one electrode is less than that of the other electrode and said one electrode constitutes the cathode electrode of a reactive sputter etching system.
Claim 4
Dependent Claim
30 words
Apparatus as in claim 2 wherein the dielectric member contains apertures therethrough to permit the back surfaces of said workpieces to be mounted directly in contact with said post regions.
Claim 5
Dependent Claim
34 words
Apparatus as in claim 3 wherein said establishing means comprises electrical connections extending from said electrodes to the exterior of said apparatus, said connections being adapted to be capacitively coupled to a radio-frequency source.
Claim 6
Dependent Claim
25 words
Apparatus as in claim 4 wherein said introducing means comprises an inlet port and tubing to carry gas from an external supply into said chamber.
Claim 7
Dependent Claim
96 words
Apparatus for etching the front surfaces of plural workpieces, said apparatus comprising a reaction chamber, two spaced-apart electrodes in said chamber, one of said electrodes having a planar base portion with post regions thereon, a dielectric plate member in contact with said base portion and encompassing said post regions, said plate member including a planar front surface having at least workpiece-sized portions removed therefrom in respective alignment with said post regions for mounting said workpieces such that the front surfaces of said workpieces lie in the same plane as the front surface of said plate member.
Claim 8
Dependent Claim
96 words
Apparatus for etching the front surfaces of plural workpieces, said apparatus comprising a reaction chamber, two spaced-apart electrodes in said chamber, one of said electrodes having a planar base portion with post regions thereon, a dielectric plate member in contact with said base portion and encompassing said post regions, said plate member including a planar front surface having at least workpiece-sized portions removed therefrom in respective alignment with said post regions for mounting said workpieces such that the front surfaces of said workpieces lie in the same plane as the front surface of said plate member.
Claim 9
Dependent Claim
32 words
Apparatus as in claim 6 wherein said portions each constitute workpiece-high recesses formed in said plate member, each such recess having substantially the same cross-sectional area as that of its associated workpiece.
Claim 10
Dependent Claim
28 words
Apparatus as in claim 6 wherein said portions each constitute a through aperture having substantially the same cross-sectional area as that of its associated post region and workpiece.
Claim 11
Dependent Claim
66 words
Apparatus as in claim 6 wherein said portions each constitute a through aperture and the cross-sectional-area of each post region is slightly less than that of its associated workpiece, each such aperture including a relatively small cross-sectional area portion closely encompassing its associated post region and a relatively large cross-sectional area workpiece-high portion whose cross-sectional area closely approximates that of the workpiece to be placed therein.
Claim 12
Independent Claim
193 words
A method of making a device by processing a workpiece in accordance with a fabrication sequence that includes at least one dry etching step in which the workpiece is positioned on one of two spaced-apart electrodes in the reaction chamber of an etching system, said one electrode having a planar base portion with a post region thereon, said method comprising mounting said workpiece on said one electrode overlying said post region and in registry therewith to maintain the front surface of said workpiece in substantially the same plane as that of surrounding dielectric material disposed on said one electrode, the thickness of said surrounding dielectric material being substantially greater than the thickness of any dielectric material interposed between the back surface of said workpiece and said post region, introducing a gas into said chamber, and establishing an electric potential between said electrodes to form in said chamber a substantially uniform electric field focussed on said workpiece thereby to convert said gas into a plasma that contains species effective to react with selected portions of said front surface in a substantially uniform and contamination-free manner to etch said portions in a relatively rapid way.
Claim 13
Independent Claim
193 words
A method of making a device by processing a workpiece in accordance with a fabrication sequence that includes at least one dry etching step in which the workpiece is positioned on one of two spaced-apart electrodes in the reaction chamber of an etching system, said one electrode having a planar base portion with a post region thereon, said method comprising mounting said workpiece on said one electrode overlying said post region and in registry therewith to maintain the front surface of said workpiece in substantially the same plane as that of surrounding dielectric material disposed on said one electrode, the thickness of said surrounding dielectric material being substantially greater than the thickness of any dielectric material interposed between the back surface of said workpiece and said post region, introducing a gas into said chamber, and establishing an electric potential between said electrodes to form in said chamber a substantially uniform electric field focussed on said workpiece thereby to convert said gas into a plasma that contains species effective to react with selected portions of said front surface in a substantially uniform and contamination-free manner to etch said portions in a relatively rapid way.
Claim 14
Dependent Claim
31 words
A method as in claim 10 wherein said etching is carried out in a reactive sputter etching step in which said workpiece is mounted on the cathode electrode in said chamber.
Claim 15
Dependent Claim
21 words
A method as in claim 11 wherein said workpiece includes thereon a selectively irradiated layer of a dry-developed negative-tone resist material.
Claim 16
Dependent Claim
15 words
A method as in claim 12 wherein the gas introduced into said chamber comprises oxygen.
Claim 17
Dependent Claim
27 words
A method as in claim 13 wherein said resist material comprises 7.5 percent by weight bis-acryloxybutyltetramethyldisiloxane in a 92.5 percent by weight host polymer of poly(2,3-dichloro-1-propyl acrylate).
Claim 18
Dependent Claim
20 words
A method as in claim 14 wherein said resist material is selectively irradiated by X-radiation in a lithographic processing step.
Claim 19
Dependent Claim
31 words
A method as in claim 15 wherein said selectively irradiated layer is fixed by heating to approximately 70 degrees Celsius under a vacuum of about 0.5 Torr for about 1 hour.
Claim 20
Dependent Claim
38 words
A method as in claim 16 wherein etching of said fixed layer is carried out at a pressure in the range 5-to-50 milliTorr at a power density of about 0.1-to-0.5 watts per square centimeter for about 5-to-10 minutes.
References Cited (Backward Citations)
US3984301A
Cited
US4232110A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |