EP0471185A2
Expired / Lapsed
EP
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Process for forming refractory metal silicide layers in an integrated circuit
Assignee: International Business Machines Corp
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Filing: 1991-07-10
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Granted: —
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Expires: 2011-07-10
Abstract
Abstract A method for forming reactive metal silicide layers at two spaced locations on a silicon substrate, which layers can be of different thicknesses and/or of different reactive metal is provided. A silicon substrate (10) has a silicon dioxide layer (14) formed thereon followed by the formation of a polysilicon layer (16) on the silicon dioxide layer (14), followed by forming layer of refractory metal (18), e.g. titanium on the polysilicon (16). A non-reflecting material (20), e.g. titanium nitride is formed on the refractory metal (18). Conventional photoresist techniques are used to pattern the titanium nitride (20), the titanium (18) and polysilicon (16), and the titanium (18) is reacted with the contacted polysilicon (16) to form a titanium silicide (24). The portion of silicon dioxide (14) overlying the silicon substrate is then removed and the exposed substrate is ion implanted to form source/drain regions (27). A second layer of refractory metal (28), either titanium or some other refractory metal, is deposited over the source/drain region (27), and either over the titanium nitride (20), or over the first formed silicide (24) by first removing the titanium nitride (20). The second layer of refractory metal (28) is reacted with the substrate at the source/drain region (27) to form a refractory metal silicide (30), after which the unreacted refractory metal (28) is removed.
Inventors
- 👤 Thomas J. Hartswick
- 👤 Carter W. Kaanta
- 👤 Pei-Ing P. Lee
- 👤 Terrance M. Wright
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 13:36
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01308; H10D64/0131; H10D64/01326; H10P; H10P76/00; H10P76/20; H10P76/204; H10P76/2041; H10P76/2043
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
215 words
A process for forming an integrated circuit having refractory metal silicide layers at two spaced regions of a silicon substrate (10) used to form an integrated circuit comprising the steps of: forming a layer of dielectric material (14) on said silicon substrate (10); forming a layer of polysilicon (16) on said layer of dielectric material (14); forming a layer of refractory metal (18) on said polysilicon; forming a layer of essentially non-reflecting material (20) on said layer of refractory metal (18); patterning said layers of polysilicon (16), said refractory metal (18) and said non-reflecting material (20); said patterned layer including exposed side walls of said polysilicon (16); heating said integrated circuit to react the refractory metal (18) with the patterned layer of polysilicon (16) to form a refractory metal silicide (24) at those locations whereat said refractory metal (18) and said polysilicon (16) are in contact; forming a layer of dielectric material (26) on the exposed side walls of said polysilicon (16); removing a portion of said dielectric material overlying said substrate to expose a portion of the silicon substrate surface while maintaining said dielectric material on the side walls of the polysilicon (16); forming a refractory metal silicide (30) on the portion of the exposed silicon substrate whereat said dielectric material (26) was removed.
Claim 2
Dependent Claim
29 words
The process as defined in claim 1 wherein the dielectric material (26) formed on the substrate and on the exposed side walls of the polysilicon (16) is silicon dioxide.
Claim 3
Dependent Claim
43 words
The process as defined in claim 1 or 2 wherein said refractory metal silicide (30) on said substrate is formed from a second layer of refractory metal (28, 29) deposited over at least said substrate portion whereat said silicon dioxide (26) was removed.
Claim 4
Dependent Claim
29 words
The process as defined in claim 3 wherein any unreacted refractory metal (28, 29) is removed after the step of forming a refractory metal silicide (30) on the substrate.
Claim 5
Dependent Claim
22 words
The process as described in anyone of the claims 1 to 4 further characterized by said non-reflecting material (20) being titanium nitride.
Claim 6
Dependent Claim
30 words
The process as described in anyone of the claims 1 to 5 wherein at least one of the refractory metals (18, 28, 29) deposited to form a silicide is titanium.
Claim 7
Dependent Claim
19 words
The process as described in claim 6 wherein both of the refractory metals (18, 28, 29) deposited are titanium.
Claim 8
Dependent Claim
40 words
The process as defined in anyone of the claims 5 to 7 wherein the silicide layer (30) formed on the substrate is formed by depositing a layer of refractory metal (28, 29) over the substrate and over the titanium nitride.
Claim 9
Dependent Claim
53 words
The process as defined in anyone of the claims 1 to 8 wherein a silicide layer on the substrate is formed by first removing the non-reflecting material (20) from the underlying silicide layers (24) and depositing a layer of refractory metal (28, 29) over both the substrate and the formed silicide layers (24).
Claim 10
Dependent Claim
21 words
The process as defined in claim 9 wherein the material used for forming the silicide layer in the substrate is titanium.
Claim 11
Dependent Claim
43 words
The process as defined in claim 2 wherein the refractory metal silicide which is formed on the exposed portion of the silicon substrate is formed by selective deposition of a refractory metal on exposed conducting materials including the exposed portion of the substrate.
Claim 12
Dependent Claim
22 words
The process as defined in claim 11 wherein said refractory metal which is selectively deposited on the exposed conducting materials is tungsten.
Claim 13
Dependent Claim
253 words
The process as defined in anyone of the claims 1 to 12 used for forming an integrated circuit having refractory metal silicide layers at two spaced regions of a silicon substrate (10) one of which regions is a gate electrode (24) and the other a source/drain region (27) comprising the steps of: forming the layer of dielectric material (14) on said silicon substrate (10); forming the layer of polysilicon (16) on said layer of dielectric material (14); forming the layer of refractory metal (18) on said polysilicon (16); forming a layer of essentially non-reflecting material (20) on said layer of refractory metal (18); patterning said layers of polysilicon (16), said refractory metal (18) and said non-reflecting material (20); said patterned layer including a gate electrode of said polysilicon (16) having exposed side walls; heating said integrated circuit of react the refractory metal (18) with the gate electrode of the patterned layer of polysilicon (16) to form a refractory metal silicide (24) at those locations whereat said refractory metal (18) and said polysilicon (16) are in contact; forming the layer of dielectric material (26) on the exposed side walls of said polysilicon gate electrode; removing a portion of said dielectric material overlying said substrate to expose a portion of the silicon substrate surface as a source/drain region (27) while maintaining said dielectric material on the side walls of the polysilicon gate electrode; forming a refractory metal silicide (30) on the source/drain region (27) of the exposed silicon substrate wherat said dielectric material was removed.
Claim 14
Dependent Claim
42 words
The process as defined in anyone of the claims 1 to 13 wherein at least one recessed oxide region is formed on said substrate, and wherein a portion of at least one patterned layer of polysilicon is disposed on said recessed oxide.
References Cited (Backward Citations)
No citation records indexed.
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