US4398341A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating a highly conductive structure
Assignee: International Business Machines Corp
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Filing: 1981-09-21
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Granted: 1983-08-16
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Expires: 2001-09-21
Abstract
Abstract An improved method of fabricating a silicide structure includes depositing a metal, e.g., molybdenum or tungsten, directly onto a thin insulating layer of silicon dioxide and/or silicon nitride formed on a semiconductor substrate, co-depositing the metal and silicon onto the metal layer and then depositing silicon onto the co-deposited metal-silicon layer. This structure is annealed at a temperature sufficient to form a metal silicide between the thin insulating layer and the layer of silicon. The silicon layer serves as a source of silicon for the metal layer which is consumed during the annealing step to form, along with the co-deposited metal-silicon layer, a relatively thick metal silicide layer directly on the thin silicon dioxide layer. A sufficiently thick silicon layer is initially provided on the co-deposited metal-silicon layer so that a portion of the initial silicon layer remains after the annealing step has been completed. This excess silicon may be oxidized to form a passivating layer on top of the thick metal silicide layer. If all or a part of the silicon in the remaining silicon layer after annealing is removed, the thick metal silicide layer may be exposed to an oxidizing ambient for self-passivation. In this latter instance, the pure metal precipitates in the silicide resulting in a line with even greater conductivity than a pure silicide line, which is very desirable for interconnections.
Inventors
- 👤 Henry J. Geipel, Jr.
- 👤 Larry A. Nesbit
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:09
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/20; H10P76/202; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01318; H10D64/0132; H10D64/01326; H10P95/00; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/058; H10W20/064; H10W20/066; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/951
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
82 words
A method of making a conductive structure comprising the steps of: depositing a layer of metal on an inert insulator, depositing a layer of atomic mixture of metal and silicon on said metal layer, depositing a layer of silicon on said layer of metal and silicon, and annealing said structure so as to convert said layer of atomic mixture of metal and silicon and substantially all of said metal layer and at least a portion of said silicon layer into metal silicide.
Claim 2
Independent Claim
82 words
A method of making a conductive structure comprising the steps of: depositing a layer of metal on an inert insulator, depositing a layer of atomic mixture of metal and silicon on said metal layer, depositing a layer of silicon on said layer of metal and silicon, and annealing said structure so as to convert said layer of atomic mixture of metal and silicon and substantially all of said metal layer and at least a portion of said silicon layer into metal silicide.
Claim 3
Dependent Claim
42 words
A method as set forth in claim 1 wherein only a portion of said silicon layer is converted into metal silicide and further including oxidizing the remaining portion of said silicon layer to form a passivating layer on said metal silicide layer.
Claim 4
Dependent Claim
18 words
A method as set forth in claim 2 wherein said oxidizing step forms a layer of silicon dioxide.
Claim 5
Dependent Claim
40 words
A method as set forth in claim 1 further including the step of etching at least some of the remaining portion of said silicon layer and oxidizing the remaining structure to form a passivating layer on said metal silicide layer.
Claim 6
Dependent Claim
41 words
A method as set forth in claim 4 wherein said oxidizing step forms a layer of silicon dioxide and said metal of said metal layer and said metal of said layer of metal and silicon are the same type of metal.
Claim 7
Dependent Claim
35 words
A method as set forth in claim 1 wherein said layer of atomic mixture of metal and silicon is deposited by co-evaporating said metal and silicon and said structure is annealed in an inert atmosphere.
Claim 8
Dependent Claim
19 words
A method as set forth in claim 6 wherein said layers are formed by using electron beam evaporation techniques.
Claim 9
Dependent Claim
43 words
A method as set forth in claim 6 wherein said layers are formed by first depositing the metal of said metal layer, then co-depositing the metal and silicon of said metal and silicon layer and finally depositing the silicon of said silicon layer.
Claim 10
Dependent Claim
22 words
A method as set forth in claim 8 wherein said layers are deposited at a temperature between 100° C. and 250° C.
Claim 11
Dependent Claim
39 words
A method as set forth in claim 9 wherein said layers are annealed at a temperature between 750° C. and 1200° C. for a period of time between 30 minutes and 60 minutes in an argon or nitrogen atmosphere.
Claim 12
Dependent Claim
60 words
A method as set forth in claim 10 wherein said inert insulator has a thickness between 30 and 50 nanometers, said metal layer has a thickness between 30 and 60 nanometers, said layer of atomic mixture of metal and silicon has a thickness between 125 and 225 nanometers and said silicon layer has a thickness between 100 and 300 nanometers.
Claim 13
Dependent Claim
30 words
A method as set forth in claim 1 wherein said metal is a refractory metal and said inert insulator includes a layer of silicon nitride deposited onto a semiconductor substrate.
Claim 14
Independent Claim
134 words
A method of making a silicide structure comprising the steps of: growing a layer of insulation on a silicon substrate, depositing a metal selected from the group consisting of molybdenum, tungsten, tantalum, titanium, cobalt and rhodium directly onto the surface of said insulation layer to form a metal layer, co-depositing said metal and silicon onto the surface of said metal layer to form a composite metal-silicon layer, depositing silicon onto said composite metal-silicon layer to form an intrinsic silicon layer, and annealing said layers in an inert atmosphere at a temperature sufficient to convert said composite metal-silicon layer, said metal layer and at least a portion of said silicon layer into a silicide layer forming a first interface with said insulation layer and a second interface with the remaining portion of said silicon layer.
Claim 15
Independent Claim
134 words
A method of making a silicide structure comprising the steps of: growing a layer of insulation on a silicon substrate, depositing a metal selected from the group consisting of molybdenum, tungsten, tantalum, titanium, cobalt and rhodium directly onto the surface of said insulation layer to form a metal layer, co-depositing said metal and silicon onto the surface of said metal layer to form a composite metal-silicon layer, depositing silicon onto said composite metal-silicon layer to form an intrinsic silicon layer, and annealing said layers in an inert atmosphere at a temperature sufficient to convert said composite metal-silicon layer, said metal layer and at least a portion of said silicon layer into a silicide layer forming a first interface with said insulation layer and a second interface with the remaining portion of said silicon layer.
Claim 16
Dependent Claim
49 words
A method as set forth in claim 13 wherein only a portion of said silicon layer is converted into a silicide layer and further including the step of oxidizing the remaining portion of said silicon layer to form a layer of silicon dioxide in contact with said silicide layer.
Claim 17
Dependent Claim
43 words
A method as set forth in claim 13 further including the step of etching at least some of the remaining portion of said silicon layer and oxidizing the remaining structure to form a layer of silicon dioxide in contact with said silicide layer.
Claim 18
Independent Claim
182 words
A method of making a conductive structure comprising the steps of: growing a layer of insulation on the surface of a semiconductor substrate, depositing a layer of photoresist onto said insulation layer, forming an opening in said photoresist layer to expose the surface of said insulation layer, depositing a metal from the group consisting of molybdenum, tungsten, tantalum, cobalt, titanium and rhodium through said opening to form a metal layer directly in contact with said insulation layer, co-depositing said metal and silicon through said opening to form a composite metal-silicon layer directly in contact with said metal layer, depositing silicon through said opening to form a silicon layer in contact with said composite metal-silicon layer, removing the remaining portion of said photoresist layer from the surface of said insulation layer, and annealing said metal, composite metal-silicon and silicon layers at a temperature sufficient to convert said metal and composite metal-silicon layers and a portion of said silicon layer into a silicide layer forming a first interface with said insulation layer and a second interface with the remaining portion of said silicon layer.
Claim 19
Independent Claim
182 words
A method of making a conductive structure comprising the steps of: growing a layer of insulation on the surface of a semiconductor substrate, depositing a layer of photoresist onto said insulation layer, forming an opening in said photoresist layer to expose the surface of said insulation layer, depositing a metal from the group consisting of molybdenum, tungsten, tantalum, cobalt, titanium and rhodium through said opening to form a metal layer directly in contact with said insulation layer, co-depositing said metal and silicon through said opening to form a composite metal-silicon layer directly in contact with said metal layer, depositing silicon through said opening to form a silicon layer in contact with said composite metal-silicon layer, removing the remaining portion of said photoresist layer from the surface of said insulation layer, and annealing said metal, composite metal-silicon and silicon layers at a temperature sufficient to convert said metal and composite metal-silicon layers and a portion of said silicon layer into a silicide layer forming a first interface with said insulation layer and a second interface with the remaining portion of said silicon layer.
Claim 20
Dependent Claim
28 words
A method as set forth in claim 16 further including the step of oxidizing the remaining portion of said silicon layer to form a layer of silicon dioxide.
Claim 21
Dependent Claim
37 words
A method as set forth in claim 16 further including the steps of etching at least some of the remaining portion of said silicon layer and oxidizing the remaining structure to form a layer of silicon dioxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |