US4980316A
Expired / Lapsed
US
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Method for producing a resist structure on a semiconductor
Assignee: Siemens AG
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Filing: 1989-07-26
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Granted: 1990-12-25
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Expires: 2009-07-26
Abstract
Abstract A method for producing a resist structure on a semiconductor material which has an opening tapering towards the semiconductor material is provided. This method can be used, for example, for the manufacturing of T-gate metallizations in a field effect transistor. In this method, a thin, upper resist layer is structured, and the structure is transferred onto a silicon nitride layer. The structure is then transferred into a thickly applied resist while widening the upper part of the etching profile. The method is accomplished by a succession of anisotropic and isotropic dry etching steps.
Inventors
- 👤 Holger Huebner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:47
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D64/00; H10D64/01; H10D64/012; H10D64/0124; H10D64/0125; H10P; H10P76/00; H10P76/20; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/95; Y10S438/951
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
177 words
A method for producing a resist structure on a semiconductor material which comprises an opening tapering towards said semiconductor material comprising the steps of: (a) applying a resist on top of said semiconductor material; (b) applying a stop layer on top of said resist; (c) applying an upper resist layer on top of said stop layer; (d) producing a window in said upper resist layer having dimensions of the base of said opening to be produced; (e) transferring said window, by anisotropic dry etching, into said stop layer; (f) transferring said window in said stop layer into said resist, by anisotropic dry etching, forming an etched-out region in said resist and removing said upper resist layer, from the top of said stop layer; (g) widening, by isotropic dry etching, said etched-out region of said resist to a prescribed depth; (h) producing, by anisotropic dry etching, a projection of said window in a layer part of said resist, facing towards said semiconductor material, down to the boundary surface of said semiconductor material; and (i) removing said stop layer.
Claim 2
Independent Claim
177 words
A method for producing a resist structure on a semiconductor material which comprises an opening tapering towards said semiconductor material comprising the steps of: (a) applying a resist on top of said semiconductor material; (b) applying a stop layer on top of said resist; (c) applying an upper resist layer on top of said stop layer; (d) producing a window in said upper resist layer having dimensions of the base of said opening to be produced; (e) transferring said window, by anisotropic dry etching, into said stop layer; (f) transferring said window in said stop layer into said resist, by anisotropic dry etching, forming an etched-out region in said resist and removing said upper resist layer, from the top of said stop layer; (g) widening, by isotropic dry etching, said etched-out region of said resist to a prescribed depth; (h) producing, by anisotropic dry etching, a projection of said window in a layer part of said resist, facing towards said semiconductor material, down to the boundary surface of said semiconductor material; and (i) removing said stop layer.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the resist is applied in a thickness of approximately 600 nm to about 1000 nm.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein the stop layer is applied in a thickness of approximately 20 nm to about 40 nm.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein the upper resist layer is applied in a thickness of approximately 200 nm to about 400 nm.
Claim 6
Dependent Claim
12 words
The method of claim 1 wherein the semiconductor material is essentially GaAs.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein the upper resist layer is polymethylmethacrylate.
Claim 8
Dependent Claim
12 words
The method of claim 1 wherein the stop layer is on nitride.
Claim 9
Independent Claim
207 words
A method for producing a resist structure on a semiconductor material which comprises an opening tapering towards said semiconductor material comprising the steps of: (a) applying a base layer of silicon nitride; (b) applying a resist on top of said base layer; (c) applying a stop layer on top of said resist; (d) applying an upper resist layer on top of said (e) producing a window in said upper resist layer having dimensions of the base of said opening to be produced; (f) transferring said window, by anisotropic dry etching, into said stop layer; (g) transferring said window in said stop layer into said resist, by anisotropic dry etching, thereby forming an etched-out region in said resist and removing said upper resist layer from the top of said stop layer; (h) widening, by isotropic dry etching, said etched-out region of said resist to a prescribed depth; (i) producing a projection, by anisotropic dry etching, of said window in a layer part of said resist which is facing towards said semiconductor material, down to the surface of the base layer; (j) continuing said projection of said window down through said base layer onto the surface of said semiconductor through additional anisotropic etching; and (k) removing said stop layer.
Claim 10
Independent Claim
207 words
A method for producing a resist structure on a semiconductor material which comprises an opening tapering towards said semiconductor material comprising the steps of: (a) applying a base layer of silicon nitride; (b) applying a resist on top of said base layer; (c) applying a stop layer on top of said resist; (d) applying an upper resist layer on top of said (e) producing a window in said upper resist layer having dimensions of the base of said opening to be produced; (f) transferring said window, by anisotropic dry etching, into said stop layer; (g) transferring said window in said stop layer into said resist, by anisotropic dry etching, thereby forming an etched-out region in said resist and removing said upper resist layer from the top of said stop layer; (h) widening, by isotropic dry etching, said etched-out region of said resist to a prescribed depth; (i) producing a projection, by anisotropic dry etching, of said window in a layer part of said resist which is facing towards said semiconductor material, down to the surface of the base layer; (j) continuing said projection of said window down through said base layer onto the surface of said semiconductor through additional anisotropic etching; and (k) removing said stop layer.
Claim 11
Dependent Claim
21 words
The method of claim 8 wherein the resist is applied in a thickness of approximately 600 nm to about 1000 nm.
Claim 12
Dependent Claim
22 words
The method of claim 8 wherein the stop layer is applied in a thickness of approximately 20 nm to about 40 nm.
Claim 13
Dependent Claim
23 words
The method of claim 8 wherein the upper resist layer is applied in a thickness of approximately 200 nm to about 400 nm.
Claim 14
Dependent Claim
12 words
The method of claim 8 wherein the semiconductor material is essentially GaAs.
Claim 15
Dependent Claim
12 words
The method of claim 8 wherein the upper resist layer is polymethylmethacrylate.
Claim 16
Dependent Claim
12 words
The method of claim 8 wherein the stop layer is silicon nitride.
Claim 17
Dependent Claim
55 words
The method of claim 8 wherein: the resist is applied in a thickness of approximately 600 nm to about 1000 nm; the stop layer is applied in a thickness of approximately 20 nm to about 40 nm; and the upper resist layer is applied in a thickness of approximately 200 nm to about 400 nm.
References Cited (Backward Citations)
US4372034A
Cited
US4372034B1
Cited
US4440804A
Cited
US4495220A
Cited
US4522681A
Cited
US4523976A
Cited
US4560436A
Cited
JPS62174945A
Cited
JPS63213930A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-24 | 1994-06-25 | 1994-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-24 | 1998-06-25 | 1998-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-24 | 2002-06-25 | 2002-12-25 | $7700.00 | Window Closed / Lapsed |