Patent US4620898A successfully refreshed from Google Patents.
US4620898A
Expired / Lapsed
US
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Ion beam sputter etching
Assignee: National Aeronautics and Space Administration
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Filing: 1985-09-13
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Granted: 1986-11-04
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Expires: 2005-09-13
Abstract
Abstract An ion beam etching process which forms extremely high aspect ratio surface microstructures using thin sputter masks is utilized in the fabrication of integrated circuits. A carbon rich sputter mask together with unmasked portions of a substrate is bombarded with inert gas ions while simultaneous carbon deposition is occurring. The arrival of the carbon deposit is adjusted to enable the sputter mask to have a near zero or even slightly positive increase in thickness with time while the unmasked portions have a high net sputter etch rate.
Inventors
- 👤 Bruce A. Banks
- 👤 Sharon K. Rutledge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:12
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/30; H01J37/305; H01J37/3053; H01J37/3056
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
72 words
A method of ion beam sputter etching a surface of a substrate comprising the steps of forming a carbon sputter mask on said surface, simultaneously bombarding said masked surface with high energy ions to sputter etch the same while depositing low energy carbon atoms thereon whereby the thickness of the carbon sputter mask remains substantially constant, and removing said carbon mask after a predetermined amount of substrate material has been sputtered away.
Claim 2
Independent Claim
72 words
A method of ion beam sputter etching a surface of a substrate comprising the steps of forming a carbon sputter mask on said surface, simultaneously bombarding said masked surface with high energy ions to sputter etch the same while depositing low energy carbon atoms thereon whereby the thickness of the carbon sputter mask remains substantially constant, and removing said carbon mask after a predetermined amount of substrate material has been sputtered away.
Claim 3
Dependent Claim
25 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 1 wherein the surface is bombarded with argon ions.
Claim 4
Dependent Claim
33 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 2 wherein the argon ions have a high energy between about 300 eV and about 2000 eV.
Claim 5
Dependent Claim
30 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 1 wherein the low energy carbon atoms have energies less than about 2 eV.
Claim 6
Independent Claim
103 words
A method of ion beam sputter etching a surface of a substrate comprising the steps of coating said surface with a layer of resist material, exposing selected areas of said resist layer to an incident flux, removing predetermined areas of said resist layer, simultaneously bombarding said surface and the remaining resist material with high energy ions to sputter etch the same while depositing low energy carbon atoms thereon whereby a carbon coating is produced on the surface of the remaining resist material thereby forming a sputter mask, and removing said carbon coating after a predetermined amount of substrate has been sputter etched away.
Claim 7
Independent Claim
103 words
A method of ion beam sputter etching a surface of a substrate comprising the steps of coating said surface with a layer of resist material, exposing selected areas of said resist layer to an incident flux, removing predetermined areas of said resist layer, simultaneously bombarding said surface and the remaining resist material with high energy ions to sputter etch the same while depositing low energy carbon atoms thereon whereby a carbon coating is produced on the surface of the remaining resist material thereby forming a sputter mask, and removing said carbon coating after a predetermined amount of substrate has been sputter etched away.
Claim 8
Dependent Claim
30 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 5 wherein said predetermined areas of said resist layer are removed by chemical solvents.
Claim 9
Dependent Claim
30 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 5 wherein the low energy carbon atoms have energies less than about 2 eV.
Claim 10
Dependent Claim
26 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 5 wherein the carbon coating is removed by chemical solvents.
Claim 11
Dependent Claim
26 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 5 wherein the carbon coating is removed by oxygen-plasma etching.
Claim 12
Dependent Claim
48 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 6 wherein said layer on said surface is a positive resist material, and said predetermined areas of said resist layer that are removed are the selected areas exposed to the incident flux.
Claim 13
Dependent Claim
33 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 10 wherein the selected areas of the positive resist material are exposed to a flux of electrons.
Claim 14
Dependent Claim
33 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 10 wherein the selected areas of the positive resist material are exposed to a flux of photons.
Claim 15
Dependent Claim
53 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 6 wherein said layer on said surface is a negative resist material, and said predetermined areas of said resist layer that are removed comprise those portions of said layer that are not exposed to the incident flux.
Claim 16
Dependent Claim
33 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 13 wherein the selected areas of the negative resist material are exposed to a flux of electron.
Claim 17
Dependent Claim
33 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 13 wherein the selected areas of the negative resist material are exposed of a flux of photons.
Claim 18
Dependent Claim
30 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 13 wherein the surface and the remaining resist material are bombarded with argon ions.
Claim 19
Dependent Claim
33 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 13 wherein the argon ions have a high energy between about 300 eV and about 2000 eV.
Claim 20
Independent Claim
133 words
A method of ion beam sputter etching a surface of a substrate comprising the steps of coating said surface with a layer of resist material, exposing selected areas of said resist layer to an incident flux, removing predetermined areas of said resist layer to expose portions of said surface, depositing a carbon coating over the remaining resist material and said exposed portions of said surface, removing said remaining resist material having the carbon coating thereon thereby uncovering sections of said surface, simultaneously bombarding said sections of said surface and the remainder of said coating with high energy ions to sputter etch the uncovered section while depositing low energy carbon atoms an said coating to maintaining the same, and removing said carbon coating after a predetermined amount of substrate has been sputter etched away.
Claim 21
Independent Claim
133 words
A method of ion beam sputter etching a surface of a substrate comprising the steps of coating said surface with a layer of resist material, exposing selected areas of said resist layer to an incident flux, removing predetermined areas of said resist layer to expose portions of said surface, depositing a carbon coating over the remaining resist material and said exposed portions of said surface, removing said remaining resist material having the carbon coating thereon thereby uncovering sections of said surface, simultaneously bombarding said sections of said surface and the remainder of said coating with high energy ions to sputter etch the uncovered section while depositing low energy carbon atoms an said coating to maintaining the same, and removing said carbon coating after a predetermined amount of substrate has been sputter etched away.
Claim 22
Dependent Claim
26 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 18 wherein the carbon coating is deposited by vapor deposition.
Claim 23
Dependent Claim
27 words
A method of ion beam sputter etching a surface of a substrate as claimed in claim 19 wherein the carbon coating is removed by oxygen plasma ashing.
Claim 24
Dependent Claim
63 words
Apparatus for ion beam sputter etching unmasked surface portions of a masked substrate to form extremely high aspect ratio surface microstructures comprising means for bombarding said masked surface with ions to sputter etch said unmasked surface portions, and means for simultaneously depositing low energy carbon atoms on masked portions of said surface to produce a carbon coating thereon thereby producing a sputter mask.
Claim 25
Dependent Claim
63 words
Apparatus for ion beam sputter etching unmasked surface portions of a masked substrate to form extremely high aspect ratio surface microstructures comprising means for bombarding said masked surface with ions to sputter etch said unmasked surface portions, and means for simultaneously depositing low energy carbon atoms on masked portions of said surface to produce a carbon coating thereon thereby producing a sputter mask.
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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) | 1989-11-03 | 1990-05-05 | 1990-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-03 | 1994-05-05 | 1994-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-03 | 1998-05-05 | 1998-11-04 | $7700.00 | Window Closed / Lapsed |