EP0279588A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Contact in a contact hole in a semiconductor and method of producing same
Assignee: Advanced Micro Devices Inc
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Filing: 1988-02-11
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Granted: —
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Expires: 2008-02-11
Abstract
Abstract A stable, low resistance contact is formed in a contact hole (16) through an insulating layer (14), e.g., silicon dioxide, formed on a surface of a semiconductor substrate (12), e.g., silicon, to a portion of a doped region (10) in said semiconductor surface. The contact comprises (a) an adhesion and contacting layer (18) of titanium formed along the walls of the insulating layer and in contact with the portion of the doped region; (b) a barrier layer (20) formed over the adhesion and contacting layer; and (c) a conductive material (22) formed over the barrier layer and at least substantially filling said contact hole. A patterned metal layer (26) forms an ohmic contact interconnect to other devices and external circuitry. The adhesion and contacting layer and barrier layer are either physically or chemically vapor deposited onto the oxide surface. The conductive layer comprises one of CVD or bias sputtered tungsten, molybdenum or in situ doped CVD polysilicon. The contact of the invention avoids the problems of encroachment at the oxide-silicon interface and worm holes associated with other contact schemes but retains process simplicity.
Inventors
- 👤 Pankaj Dixit
- 👤 Jack Sliwa
- 👤 Richard K. Klein
- 👤 Craig S. Sander
- 👤 Mohammad Farnaam
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 12:02
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/033; H10W20/035; H10W20/056; H10W20/057; Y; Y10; Y10S; Y10S257/00; Y10S257/915
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
99 words
A stable, low resistance contact formed in a contact hole through at least one insulating layer formed on a semiconductor surface to a portion of a doped region in said semiconductor surface, said contact comprising: (a) an adhesion and contacting layer of titanium formed at least along the walls of said contact hole through said at least one insulating layer and in contact with said portion of said doped region; (b) a barrier layer formed over said adhesion and contacting layer; and (c) a conductive material formed over said barrier layer and at least substantially filling said contact hole.
Claim 2
Dependent Claim
99 words
A stable, low resistance contact formed in a contact hole through at least one insulating layer formed on a semiconductor surface to a portion of a doped region in said semiconductor surface, said contact comprising: (a) an adhesion and contacting layer of titanium formed at least along the walls of said contact hole through said at least one insulating layer and in contact with said portion of said doped region; (b) a barrier layer formed over said adhesion and contacting layer; and (c) a conductive material formed over said barrier layer and at least substantially filling said contact hole.
Claim 3
Dependent Claim
21 words
The contact of Claim 1 wherein said titanium adhesion and contacting layer has a thickness of about 100 to 800 Å.
Claim 4
Dependent Claim
36 words
The contact of Claim 1 wherein said barrier layer comprises a material selected from the group consisting of tungsten, molybdenum, titanium-tungsten, titanium nitride, titanium tungsten nitride, tungsten nitride, molybdenum nitride, chromium, chromium-chromium oxide, and boron nitride.
Claim 5
Dependent Claim
27 words
The contact of Claim 3 wherein said barrier layer comprises a material selected from the group consisting of titanium nitride, titanium-tungsten, titanium tungsten nitride, and boron nitride.
Claim 6
Dependent Claim
14 words
The contact of Claim 4 wherein said barrier layer consists essentially of titanium nitride.
Claim 7
Dependent Claim
18 words
The contact of Claim 1 wherein said barrier layer has a thickness of about 250 to 2,000 Å.
Claim 8
Dependent Claim
21 words
The contact of Claim 1 wherein said conductive material is selected from the group consisting of tungsten, molybdenum and doped polysilicon.
Claim 9
Dependent Claim
24 words
The contact of Claim 7 wherein said tungsten conductive material is situated on an additional CVD tungsten silicide layer formed on said barrier layer.
Claim 10
Dependent Claim
40 words
The contact of Claim 1 wherein said adhesion and contacting and said barrier layers cover all of said doped regions and most of said side walls and wherein said conductive material substantially fills said contact hole and is contained therein.
Claim 11
Dependent Claim
135 words
A stable, low resistance contact formed in a contact hole through at least one insulating layer formed on a semiconductor surface to a portion of a doped region in said semiconductor surface, said contact comprising: (a) an adhesion and contacting layer of titanium formed at least along the walls of said contact hole through said at least one insulating layer and in contact with said portion of said doped region; (b) a barrier layer comprising a material selected from the group consisting of titanium nitride, titanium-tungsten, titanium tungsten nitride, and boron nitride formed over said adhesion and contacting layer; and (c) a conductive material selected from the group consisting of in situ doped polysilicon and CVD or bias sputtered tungsten and molybdenum formed over said barrier layer and at least substantially filling said contact hole.
Claim 12
Dependent Claim
135 words
A stable, low resistance contact formed in a contact hole through at least one insulating layer formed on a semiconductor surface to a portion of a doped region in said semiconductor surface, said contact comprising: (a) an adhesion and contacting layer of titanium formed at least along the walls of said contact hole through said at least one insulating layer and in contact with said portion of said doped region; (b) a barrier layer comprising a material selected from the group consisting of titanium nitride, titanium-tungsten, titanium tungsten nitride, and boron nitride formed over said adhesion and contacting layer; and (c) a conductive material selected from the group consisting of in situ doped polysilicon and CVD or bias sputtered tungsten and molybdenum formed over said barrier layer and at least substantially filling said contact hole.
Claim 13
Dependent Claim
114 words
A stable, low resistance contact formed in a contact hole through a layer of silicon dioxide formed on a silicon surface to a portion of a doped region in said silicon surface, said contact comprising: (a) an adhesion and contacting layer of sputtered titanium formed at least along the walls of said contact hole through said silicon dioxide and in contact with said portion of said doped region; (b) a barrier layer of sputtered titanium nitride formed over said adhesion and contacting layer; and (c) a CVD conductive material selected from the group consisting of tungsten and in situ doped polysilicon formed over said barrier layer and at least substantially filling said contact hole.
Claim 14
Dependent Claim
114 words
A stable, low resistance contact formed in a contact hole through a layer of silicon dioxide formed on a silicon surface to a portion of a doped region in said silicon surface, said contact comprising: (a) an adhesion and contacting layer of sputtered titanium formed at least along the walls of said contact hole through said silicon dioxide and in contact with said portion of said doped region; (b) a barrier layer of sputtered titanium nitride formed over said adhesion and contacting layer; and (c) a CVD conductive material selected from the group consisting of tungsten and in situ doped polysilicon formed over said barrier layer and at least substantially filling said contact hole.
Claim 15
Dependent Claim
160 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a semiconductor substrate; (b) forming at least one insulating layer over said doped regions in the surrounding substrate; (c) forming contact holes of substantially uniform size through said at least one insulating layer in selected areas of said doped regions, said holes defined by walls of said insulating layer; (d) forming an adhesion and contacting layer of titanium at least in said holes, including along said walls, in contact with the underlying doped region, said adhesion and contacting layer formed to a thickness insufficient to fill said contact holes; (e) forming a barrier layer in contact with said adhesion and contacting layer, said barrier layer formed to a thickness insufficient to fill said contact holes; and (f) forming a contact plug comprising a conductive material which substantially fills said contact holes and which is in contact with said barrier layer.
Claim 16
Dependent Claim
160 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a semiconductor substrate; (b) forming at least one insulating layer over said doped regions in the surrounding substrate; (c) forming contact holes of substantially uniform size through said at least one insulating layer in selected areas of said doped regions, said holes defined by walls of said insulating layer; (d) forming an adhesion and contacting layer of titanium at least in said holes, including along said walls, in contact with the underlying doped region, said adhesion and contacting layer formed to a thickness insufficient to fill said contact holes; (e) forming a barrier layer in contact with said adhesion and contacting layer, said barrier layer formed to a thickness insufficient to fill said contact holes; and (f) forming a contact plug comprising a conductive material which substantially fills said contact holes and which is in contact with said barrier layer.
Claim 17
Dependent Claim
20 words
The process of Claim 12 wherein said titanium adhesion and contacting layer is deposited by sputtering from a titanium target.
Claim 18
Dependent Claim
19 words
14 . The process of Claim 12 wherein said barrier layer is deposited by sputtering, CVD or reactive annealing.
Claim 19
Dependent Claim
23 words
15 . The process of Claim 12 wherein said conductive material is selected from the group consisting of tungsten, molybdenum and doped polysilicon.
Claim 20
Dependent Claim
32 words
16 . The process of Claim 12 wherein said adhesion and contacting layer, said barrier layer and said conductive material are blanket deposited on said insulating layer, including in said contact holes.
Claim 21
Dependent Claim
94 words
17 . The process of Claim 16 wherein (a) said conductive material is etched back to expose said barrier layer on said insulating layer but leaving said conductive layer substantially filling said contact hole, thereby preserving said contact plug; (b) a metal layer is formed on said exposed barrier layer and in electrical contact with said contact plug; and (c) said metal layer and said underlying barrier layer and adhesion and contacting layer are patterned and etched to expose portions of said insulating layer, leaving defined patterns of said metal layer forming interconnect regions.
Claim 22
Dependent Claim
17 words
18 . The process of Claim 17 wherein said metal layer comprises aluminum or an alloy thereof.
Claim 23
Dependent Claim
68 words
The process of Claim 16 wherein said conductive material comprises tungsten and wherein said conductive material and said underlying barrier layer and adhesion and contacting layer are patterned and etched to expose portions of said insulating layer, leaving defined patterns of said conductive material and said barrier layer and said adhesion and contacting layer forming interconnect regions, with said interconnect regions at least partially overlying said contact holes.
Claim 24
Dependent Claim
124 words
20 . The process of Claim 12 wherein (a) said adhesion and contacting layer and said barrier layer are blanket deposited on said insulating layer and in said contact holes, (b) a resist layer is blanket deposited on said barrier layer and in said contact holes sufficient to fill said contact holes substantially completely, (c) said resist and said barrier layer and adhesion and contacting layer are blanket etched to expose said insulating layer, leaving a plug of resist in said contact holes and thereby preserving said adhesion and contacting layer and said barrier layer along the surface of said doped region and at least portions of said walls of said contact holes, and (d) removing said plug of resist from said contact holes.
Claim 25
Dependent Claim
25 words
21 . The process of Claim 20 wherein tungsten is selectively deposited in said contact holes only to form said contact plug of conductive material.
Claim 26
Dependent Claim
55 words
22 . The process of Claim 20 wherein a conductive material selected from the group consisting of doped polysilicon and tungsten is blanket deposited sufficient to fill said contact holes substantially completely, and then blanket etched to leave said contact plug of conductive material contained within said contact walls and substantially filling said contact hole.
Claim 27
Dependent Claim
207 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a silicon substrate; (b) forming an insulating layer of silicon dioxide over said doped regions in the surrounding substrate; (c) forming contact holes through said silicon dioxide of substantially uniform size in selected areas of said doped regions to expose portions thereof, with said contact holes defined by walls of said insulating layer; (d) sputtering an adhesion and contacting layer of titanium at least in said holes, including along said walls, in contact with the underlying doped region, said adhesion and contacting layer formed to a thickness insufficient to fill said contact holes; (e) forming a barrier layer comprising a material selected from the group consisting of titanium nitride, titanium-tungsten, titanium tungsten nitride, and boron nitride in said contact holes in contact with said adhesion and contacting layer, said barrier layer formed to a thickness insufficient to fill said contact holes; and (f) forming a contact plug comprising a conductive material which substantially fills said contact holes and which is in contact with said barrier layer, said contact plug formed by depositing by CVD a conductive material selected from the group consisting of tungsten and doped polysilicon.
Claim 28
Dependent Claim
207 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a silicon substrate; (b) forming an insulating layer of silicon dioxide over said doped regions in the surrounding substrate; (c) forming contact holes through said silicon dioxide of substantially uniform size in selected areas of said doped regions to expose portions thereof, with said contact holes defined by walls of said insulating layer; (d) sputtering an adhesion and contacting layer of titanium at least in said holes, including along said walls, in contact with the underlying doped region, said adhesion and contacting layer formed to a thickness insufficient to fill said contact holes; (e) forming a barrier layer comprising a material selected from the group consisting of titanium nitride, titanium-tungsten, titanium tungsten nitride, and boron nitride in said contact holes in contact with said adhesion and contacting layer, said barrier layer formed to a thickness insufficient to fill said contact holes; and (f) forming a contact plug comprising a conductive material which substantially fills said contact holes and which is in contact with said barrier layer, said contact plug formed by depositing by CVD a conductive material selected from the group consisting of tungsten and doped polysilicon.
Claim 29
Dependent Claim
23 words
The process of Claim 23 wherein said barrier layer consists essentially of titanium nitride, formed by sputtering titanium in an ambient containing nitrogen.
Claim 30
Dependent Claim
25 words
The process of Claim 23 wherein said metal layer comprises aluminum or an alloy thereof, sputter-deposited to a thickness of about 2,000 to 10,000 Å.
Claim 31
Dependent Claim
19 words
The process of Claim 25 wherein said tungsten plug is formed selectively by CVD reaction of WF₆ and H₂.
Claim 32
Dependent Claim
53 words
The process of Claim 26 wherein a conductive material selected from the group consisting of doped polysilicon and tungsten is blanket deposited sufficient to fill said contact holes substantially completely, and then blanket etched to leave said contact plug of conductive material contained within said contact walls and substantially filling said contact hole.
Claim 33
Dependent Claim
14 words
The process of Claim 27 wherein said doped polysilicon comprises in situ -doped polysilicon.
Claim 34
Dependent Claim
189 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a silicon substrate; (b) forming an insulating layer of silicon dioxide over said doped regions in the surrounding substrate; (c) forming contact holes through said silicon dioxide of substantially uniform size in selected areas of said doped regions to expose portions thereof, with said contact holes defined by walls of said insulating layer; (d) blanket sputtering an adhesion and contacting layer of titanium over said silicon dioxide and into said contact holes in contact with the underlying said doped region, said adhesion and contacting layer formed to a thickness ranging from about 100 to 800 Å; (e) blanket sputtering a barrier layer consisting essentially of titanium nitride in contact with said adhesion and contacting layer, said barrier layer formed to a thickness ranging from about 250 to 2,000 Å; and (f) forming a contact plug comprising a conductive material which substantially fills said contact holes and which is in contact with said barrier layer, said conductive material selected from the group consisting of tungsten and in situ doped polysilicon.
Claim 35
Dependent Claim
189 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a silicon substrate; (b) forming an insulating layer of silicon dioxide over said doped regions in the surrounding substrate; (c) forming contact holes through said silicon dioxide of substantially uniform size in selected areas of said doped regions to expose portions thereof, with said contact holes defined by walls of said insulating layer; (d) blanket sputtering an adhesion and contacting layer of titanium over said silicon dioxide and into said contact holes in contact with the underlying said doped region, said adhesion and contacting layer formed to a thickness ranging from about 100 to 800 Å; (e) blanket sputtering a barrier layer consisting essentially of titanium nitride in contact with said adhesion and contacting layer, said barrier layer formed to a thickness ranging from about 250 to 2,000 Å; and (f) forming a contact plug comprising a conductive material which substantially fills said contact holes and which is in contact with said barrier layer, said conductive material selected from the group consisting of tungsten and in situ doped polysilicon.
Claim 36
Dependent Claim
92 words
The process of Claim 29 wherein (a) said conductive material is etched back to expose said barrier layer on said insulating layer but leaving said conductive material substantially filling said contact hole, thereby preserving said contact plug; (b) a metal layer is formed on said exposed barrier layer and in electrical contact with said contact plug; and (c) said metal layer and said underlying barrier layer and adhesion and contacting layer are patterned and etched to expose portions of said insulating layer, leaving defined patterns of said metal layer forming interconnect regions.
Claim 37
Dependent Claim
15 words
The process of Claim 30 wherein said metal layer comprises aluminum or an alloy thereof.
Claim 38
Dependent Claim
271 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a silicon substrate; (b) forming an insulating layer of silicon dioxide over said doped regions in the surrounding said silicon substrate; (c) forming contact holes through said silicon dioxide of substantially uniform size in selected areas of said doped regions to expose portions thereof, with said contact holes defined by walls of said insulating layer; (d) blanket sputtering an adhesion and contacting layer of titanium over said oxide and into said holes in contact with the underlying doped region, said adhesion and contacting layer formed to a thickness ranging from about 100 to 800 Å; (e) blanket sputtering a barrier layer consisting essentially of titanium nitride in contact with said adhesion and contacting layer, said barrier layer formed to a thickness ranging from about 250 to 2,000 Å; and (f) blanket depositing a resist layer on said barrier layer, including in said contact holes sufficient to fill said contact holes substantially completely; (g) blanket etching said resist layer, said barrier layer and said adhesion and contacting layer to expose said insulating layer, leaving a plug of resist in said contact holes and thereby preserving said adhesion and contacting layer and said barrier layer along the surface of said doped region and at least portions of said walls of said contact holes; (h) removing said resist plug; and (i) forming a contact plug comprising a conductive material selected from the group consisting of tungsten and doped polysilicon which substantially fills said contact holes and which is in contact with said barrier layer.
Claim 39
Dependent Claim
271 words
A process for fabricating stable, low resistance contacts in an integrated semiconductor circuit which comprises: (a) providing doped regions in a silicon substrate; (b) forming an insulating layer of silicon dioxide over said doped regions in the surrounding said silicon substrate; (c) forming contact holes through said silicon dioxide of substantially uniform size in selected areas of said doped regions to expose portions thereof, with said contact holes defined by walls of said insulating layer; (d) blanket sputtering an adhesion and contacting layer of titanium over said oxide and into said holes in contact with the underlying doped region, said adhesion and contacting layer formed to a thickness ranging from about 100 to 800 Å; (e) blanket sputtering a barrier layer consisting essentially of titanium nitride in contact with said adhesion and contacting layer, said barrier layer formed to a thickness ranging from about 250 to 2,000 Å; and (f) blanket depositing a resist layer on said barrier layer, including in said contact holes sufficient to fill said contact holes substantially completely; (g) blanket etching said resist layer, said barrier layer and said adhesion and contacting layer to expose said insulating layer, leaving a plug of resist in said contact holes and thereby preserving said adhesion and contacting layer and said barrier layer along the surface of said doped region and at least portions of said walls of said contact holes; (h) removing said resist plug; and (i) forming a contact plug comprising a conductive material selected from the group consisting of tungsten and doped polysilicon which substantially fills said contact holes and which is in contact with said barrier layer.
Claim 40
Dependent Claim
29 words
The process of Claim 32 wherein said resist plug is removed and tungsten is selectively deposited in said contact holes only to form said contact plug of conductive material.
Claim 41
Dependent Claim
49 words
The process of Claim 32 wherein said resist plug is removed and said conductive material is blanket deposited sufficient to fill said contact holes substantially completely, and then blanket etched to leave said contact plug of conductive material contained within said contact walls and substantially filling said contact hole.
References Cited (Backward Citations)
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