US5389575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-aligned contact diffusion barrier method
Assignee: Raytheon Co
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Filing: 1993-03-29
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Granted: 1995-02-14
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Expires: 2013-03-29
Abstract
Abstract A method of forming a contact diffusion barrier in a thin geometry integrated circuit device involves implanting a second material into a low resistivity material that overlies the semiconductor to which contact is desired. The low resistivity and implanted materials are selected to intereact with each other and form a contact diffusion barrier. Both materials may include transition metals, in which case the diffusion barrier is a composite transition metal. Alternately, the low resistivity material may include a transition metal, while implantation is performed with nitrogen. The implantation is performed by plasma etching, preferably with active cooling, which can be combined in a continuous step with the etching of the contact opening. The resulting contact diffusion barrier is self-aligned with the contact opening, and is established only in the immediate vicinity of the opening.
Inventors
- 👤 Maw-Rong Chin
- 👤 Gary Warren
- 👤 Kuan-Yang Liao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:04
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/40; H10P14/418; Y; Y10; Y10S; Y10S438/00; Y10S438/913
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
188 words
A method of preparing a semiconductor with a contact diffusion barrier, comprising: forming a layer of low resistivity material over the semiconductor, forming an insulating layer over said low resistivity layer, forming a contact opening in said insulating layer in a plasma process by unheated plasma etching with a first plasma substance; changing said plasma substance when the etching of said contact opening has been completed to a second plasma substance that reacts with said low resistivity material to resist diffusion from a overlying metal contact material into said semiconductor; reacting said second plasma substance with said low resistivity material through said contact opening by a continuation of said unheated plasma process to form a conductive diffusion barrier in said low resistivity layer, said insulating layer acting as an implantation mask during said continued plasma process; and forming a body of electrical contact material in said opening that contacts said conductive diffusion barrier and is self-aligned with said conductive diffusion barrier and is self-aligned with said conductive diffusion barrier by said contact opening with said conductive diffusion barrier resisting diffusion from said electrical contact material into the semiconductor.
Claim 2
Independent Claim
188 words
A method of preparing a semiconductor with a contact diffusion barrier, comprising: forming a layer of low resistivity material over the semiconductor, forming an insulating layer over said low resistivity layer, forming a contact opening in said insulating layer in a plasma process by unheated plasma etching with a first plasma substance; changing said plasma substance when the etching of said contact opening has been completed to a second plasma substance that reacts with said low resistivity material to resist diffusion from a overlying metal contact material into said semiconductor; reacting said second plasma substance with said low resistivity material through said contact opening by a continuation of said unheated plasma process to form a conductive diffusion barrier in said low resistivity layer, said insulating layer acting as an implantation mask during said continued plasma process; and forming a body of electrical contact material in said opening that contacts said conductive diffusion barrier and is self-aligned with said conductive diffusion barrier and is self-aligned with said conductive diffusion barrier by said contact opening with said conductive diffusion barrier resisting diffusion from said electrical contact material into the semiconductor.
Claim 3
Dependent Claim
28 words
The method of claim 1, wherein said low resistivity material and said second plasma substance both include transition metals, and said diffusion barrier comprises a composite transition metal.
Claim 4
Dependent Claim
31 words
The method of claim 1, wherein said low resistivity material includes a transition metal, said second plasma substance is nitrogen, and said diffusion barrier comprises the nitride of said transition metal.
Claim 5
Dependent Claim
44 words
The method of claim 1, wherein said low resistivity material comprises TiSi 2 , and said continuation of said unheated plasma process is performed with nitrogen at a direct current (DC) bias of at least 500 volts to produce said diffusion barrier of TiN.
Claim 6
Dependent Claim
66 words
The method of claim 1, wherein said step of reacting said second plasma substance with said low resistivity material is performed to a depth at which the thickness of the diffusion barrier is less than that of the original low resistivity material layer prior to said step of reacting, and a portion of the low resistivity material is interposed between said diffusion barrier and said semiconductor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-02-13 | 1998-08-15 | 1999-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-13 | 2002-08-15 | 2003-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-13 | 2006-08-15 | 2007-02-14 | $7700.00 | Window Closed / Lapsed |