US6277739B1
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US
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Method of forming a barrier layer underlying a tungsten plug structure in a high aspect ratio contact hole
Assignee: Vanguard International Semiconductor Corp
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Filing: 2000-10-30
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Granted: 2001-08-21
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Expires: 2020-10-30
Abstract
Abstract A process for forming a metal silicide layer on a conductive region in a semiconductor substrate, located at the bottom of a high aspect ratio contact hole, and for selectively forming a barrier layer on the underlying metal silicide layer, has been developed. After opening a high aspect ratio contact hole in an insulator layer, titanium ions are directionally implanted into a top portion of the conductive region, exposed at the bottom of the high aspect ratio contact hole. An anneal procedure, performed in a nitrogen containing ambient, results in the selective formation of a metal silicide layer, such as titanium disilicide, on the conductive region, and results in the selective formation of a barrier layer, such as titanium nitride, on the underlying metal silicide layer. Formation of a metal plug structure, in the high aspect ratio contact hole, overlying and contacting the underlying barrier layer, followed by formation of an overlying metal interconnect structure, is then accomplished.
Inventors
- 👤 Horng-Huei Tseng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:17
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/047; H10W20/048; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10W20/033
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
213 words
A method of fabricating a metal silicide layer, and an overlying barrier layer, on a conductive region in a semiconductor substrate, exposed at the bottom of a contact hole, comprising the steps of: providing said conductive region, in said semiconductor substrate; depositing an insulator layer; opening a contact hole in said insulator layer, exposing a portion of top surface of said conductive region, located at the bottom of said contact hole; implanting metal ions into a top portion of said conductive region, exposed at bottom of said contact hole, and into a top portion of said insulator layer; performing an anneal procedure in a nitrogen containing ambient to form said metal silicide layer on said conductive region, and to selectively form overlying, said barrier layer, on said metal silicide layer, with said barrier layer formed from said metal ions, and from nitrogen available in said nitrogen containing ambient, while said metal ions in said top portion of said insulator layer remain unreacted; forming a metal plug structure in said contact hole, overlying and contacting said barrier layer located on said metal silicide layer, removing said top portion of said insulator layer, comprised with said unreacted metal ions; and forming a metal interconnect structure, overlying and contacting top surface of said metal plug structure.
Claim 2
Independent Claim
213 words
A method of fabricating a metal silicide layer, and an overlying barrier layer, on a conductive region in a semiconductor substrate, exposed at the bottom of a contact hole, comprising the steps of: providing said conductive region, in said semiconductor substrate; depositing an insulator layer; opening a contact hole in said insulator layer, exposing a portion of top surface of said conductive region, located at the bottom of said contact hole; implanting metal ions into a top portion of said conductive region, exposed at bottom of said contact hole, and into a top portion of said insulator layer; performing an anneal procedure in a nitrogen containing ambient to form said metal silicide layer on said conductive region, and to selectively form overlying, said barrier layer, on said metal silicide layer, with said barrier layer formed from said metal ions, and from nitrogen available in said nitrogen containing ambient, while said metal ions in said top portion of said insulator layer remain unreacted; forming a metal plug structure in said contact hole, overlying and contacting said barrier layer located on said metal silicide layer, removing said top portion of said insulator layer, comprised with said unreacted metal ions; and forming a metal interconnect structure, overlying and contacting top surface of said metal plug structure.
Claim 3
Dependent Claim
35 words
The method of claim 1 , wherein said insulator layer is a silicon oxide layer, or a borophosphosilicate glass layer, obtained via LPCVD or PECVD procedures at a thickness between about 3000 to 12000 Angstroms.
Claim 4
Dependent Claim
33 words
The method of claim 1 , wherein diameter of said contact hole is between about 0.05 to 2.0 um, resulting in an aspect ratio for said contact hole between about 2 to 10.
Claim 5
Dependent Claim
23 words
The method of claim 1 , wherein said metal ions are titanium ions, implanted at an angle between about 0 to 7 degrees.
Claim 6
Dependent Claim
32 words
The method of claim 1 , wherein said anneal procedure is performed at a temperature between about 600 to 900° C., in a conventional furnace or in a rapid thermal anneal furnace.
Claim 7
Dependent Claim
26 words
The method of claim 1 , wherein said nitrogen containing ambient is comprised of either N 2 , NO, N 2 O, or NH 3 .
Claim 8
Dependent Claim
16 words
The method of claim 1 , wherein said metal silicide layer is a titanium disilicide layer.
Claim 9
Dependent Claim
15 words
The method of claim 1 , wherein said barrier layer is a titanium nitride layer.
Claim 10
Dependent Claim
55 words
The method of claim 1 , wherein said metal plug structure is comprised from a tungsten layer, obtained via LPCVD procedures at a thickness between about 1000 to 5000 Angstroms, then defined via a chemical mechanical polishing procedure, or via a selective RIE procedure, using Cl 2 or SF 6 as an etchant for tungsten.
Claim 11
Dependent Claim
26 words
The method of claim 1 , wherein said top portion of said insulator layer, containing unreacted metal ions, is removed using a buffered hydrofluoric acid solution.
Claim 12
Independent Claim
284 words
A method of selectively forming a titanium nitride barrier layer on an underlying titanium disilicide layer that in turn is formed on a portion of a conductive region in a semiconductor substrate, exposed at the bottom of a high aspect ratio contact hole, comprising the steps of: providing said conductive region in said semiconductor substrate; depositing an insulator layer; performing an anisotropic dry etch procedure to form said high aspect ratio contact hole in said insulator layer, exposing a portion of the top surface of said conductive region, located at the bottom of said high aspect ratio contact hole; performing an ion implantation procedure to implant titanium ions into a top portion of said conductive region, exposed at the bottom of said high aspect ratio contact hole, and into a top portion of said insulator layer; performing an anneal procedure in a nitrogen containing ambient, to form said titanium disilicide layer on said conductive region, exposed at the bottom of said high aspect ratio contact hole, and selectively forming said titanium nitride barrier layer on said titanium disilicide layer, while said titanium ions, in said top portion of said insulator layer, remain unreacted; depositing a tungsten layer completely filling said high aspect ratio contact hole; removing portions of said tungsten layer from the top surface of said insulator layer, defining a tungsten plug structure in said high aspect ratio contact hole, overlying and contacting said titanium nitride barrier layer located at the bottom of said high aspect ratio contact hole; performing a wet etch dip procedure to remove said top portion of said insulator layer, comprised with said unreacted titanium ions; and forming a metal interconnect structure, overlying and contacting said tungsten plug structure.
Claim 13
Independent Claim
284 words
A method of selectively forming a titanium nitride barrier layer on an underlying titanium disilicide layer that in turn is formed on a portion of a conductive region in a semiconductor substrate, exposed at the bottom of a high aspect ratio contact hole, comprising the steps of: providing said conductive region in said semiconductor substrate; depositing an insulator layer; performing an anisotropic dry etch procedure to form said high aspect ratio contact hole in said insulator layer, exposing a portion of the top surface of said conductive region, located at the bottom of said high aspect ratio contact hole; performing an ion implantation procedure to implant titanium ions into a top portion of said conductive region, exposed at the bottom of said high aspect ratio contact hole, and into a top portion of said insulator layer; performing an anneal procedure in a nitrogen containing ambient, to form said titanium disilicide layer on said conductive region, exposed at the bottom of said high aspect ratio contact hole, and selectively forming said titanium nitride barrier layer on said titanium disilicide layer, while said titanium ions, in said top portion of said insulator layer, remain unreacted; depositing a tungsten layer completely filling said high aspect ratio contact hole; removing portions of said tungsten layer from the top surface of said insulator layer, defining a tungsten plug structure in said high aspect ratio contact hole, overlying and contacting said titanium nitride barrier layer located at the bottom of said high aspect ratio contact hole; performing a wet etch dip procedure to remove said top portion of said insulator layer, comprised with said unreacted titanium ions; and forming a metal interconnect structure, overlying and contacting said tungsten plug structure.
Claim 14
Dependent Claim
35 words
The method of claim 11 , wherein said insulator layer is a silicon oxide layer, or a boro-phosphosilicate glass layer, obtained via LPCVD or PECVD procedures at a thickness between about 3000 to 12000 Angstroms.
Claim 15
Dependent Claim
32 words
The method of claim 11 , wherein diameter of said high aspect ratio contact hole is between about 0.05 to 2.0 um, resulting in an aspect ratio between about 2 to 10.
Claim 16
Dependent Claim
22 words
The method of claim 11 , wherein said titanium ions are implanted at an implant angle between about 0 to 7 degrees.
Claim 17
Dependent Claim
32 words
The method of claim 11 , wherein said anneal procedure is performed at a temperature between about 600 to 900° C., in a conventional furnace or in a rapid thermal anneal furnace.
Claim 18
Dependent Claim
32 words
The method of claim 11 , wherein nitrogen component, in said nitrogen containing ambient, is chosen from a group that includes N 2 , NO, N 2 O, or NH 3 .
Claim 19
Dependent Claim
21 words
The method of claim 11 , wherein said tungsten layer is obtained at a thickness between about 1000 to 5000 Angstroms.
Claim 20
Dependent Claim
36 words
The method of claim 11 , wherein said tungsten plug structure is defined via a chemical mechanical polishing procedure, or via a selective RIE procedure, using Cl 2 or SF 6 as an etchant for tungsten.
Claim 21
Dependent Claim
33 words
The method of claim 11 , wherein said wet dip procedure, used to remove said top portion of said insulator layer, containing unreacted metal ions, is performed using a buffered hydrofluoric acid solution.
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