US5510295A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for lowering the phase transformation temperature of a metal silicide
Assignee: GlobalFoundries Inc
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Filing: 1993-10-29
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Granted: 1996-04-23
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Expires: 2013-10-29
Abstract
Abstract The phase transformation temperature of a metal silicide layer formed overlying a silicon layer on a semiconductor wafer is lowered. First, a refractory metal is disposed proximate to the surface of the silicon layer, a precursory metal is deposited in a layer overlying the refractory metal, and the wafer is heated to a temperature sufficient to form the metal silicide from the precursory metal. The precursory metal may be a refractory metal, and is preferably titanium, tungsten, or cobalt. The concentration of the refractory metal at the surface of the silicon layer is preferably less than about 10 17 atoms/cm 3 . The refractory metal may be Mo, Co, W, Ta, Nb, Ru, or Cr, and more preferably is Mo or Co. The heating step used to form the silicide is performed at a temperature less than about 700° C., and more preferably between about 600°-700° C. Optionally, the wafer is annealed following the step of disposing the refractory metal and prior to the step of depositing the precursory metal layer. Preferably, this annealing step is performed at a wafer temperature of at least about 900° C.
Inventors
- 👤 Cyril Cabral, Jr.
- 👤 Lawrence A. Clevenger
- 👤 Francois M. D'Heurle
- 👤 James M. E. Harper
- 👤 Randy W. Mann
- 👤 Glen L. Miles
- 👤 Donald W. D. Rakowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:34
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/22; C23C16/30; C23C16/42; C30; C30B; C30B1/00; C30B1/02; C30B29/00; C30B29/10; H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0212; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; Y; Y10; Y10S; Y10S148/00; Y10S148/04; Y10S148/147
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
88 words
A method for forming a C54 phase titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: depositing a titanium layer on said silicon layer from a source of titanium, said titanium layer containing less than 1 atomic % of a refractory metal deposited from the same source as said titanium layer; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 2
Independent Claim
88 words
A method for forming a C54 phase titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: depositing a titanium layer on said silicon layer from a source of titanium, said titanium layer containing less than 1 atomic % of a refractory metal deposited from the same source as said titanium layer; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said refractory metal is Mo, Co, W, Ta, Nb, or Cr.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein said source is a sputtering target.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein said source is an evaporation pellet.
Claim 6
Independent Claim
84 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by sputtering, said refractory metal occurring in a layer less than 2 nm thick; depositing a titanium layer over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 7
Independent Claim
84 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by sputtering, said refractory metal occurring in a layer less than 2 nm thick; depositing a titanium layer over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 8
Dependent Claim
14 words
The method of claim 5 wherein said refractory metal is Mo, Ta or W.
Claim 9
Dependent Claim
44 words
The method of claim 5 further comprising the step of annealing said wafer following said step of disposing a refractory metal and prior to said step of depositing a titanium layer, said annealing being at a wafer temperature between about 900° to 1000° C.
Claim 10
Independent Claim
85 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by metal evaporation, said refractory metal occurring in a layer less than 2 nm thick; depositing a titanium layer over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 11
Independent Claim
85 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by metal evaporation, said refractory metal occurring in a layer less than 2 nm thick; depositing a titanium layer over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 12
Dependent Claim
14 words
The method of claim 8 wherein said refractory metal is Mo, Ta or W.
Claim 13
Dependent Claim
44 words
The method of claim 8 further comprising the step of annealing said wafer following said step of disposing a refractory metal and prior to said step of depositing a titanium layer, said annealing being at a wafer temperature between about 900° to 1000° C.
Claim 14
Independent Claim
97 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by exposing the surface of said silicon layer to a solution containing said refractory metal, said refractory metal occurring in a layer less than 2 nm thick; depositing a titanium layer over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 15
Independent Claim
97 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by exposing the surface of said silicon layer to a solution containing said refractory metal, said refractory metal occurring in a layer less than 2 nm thick; depositing a titanium layer over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said titanium layer, said temperature being less than about 700° C.
Claim 16
Dependent Claim
14 words
The method of claim 11 wherein said refractory metal is Mo, Ta or W.
Claim 17
Dependent Claim
44 words
The method of claim 11 further comprising the step of annealing said wafer following said step of disposing a refractory metal and prior to said step of depositing a titanium layer, said annealing being at a wafer temperature between about 900° to 1000° C.
Claim 18
Dependent Claim
10 words
The method of claim 11 wherein said solution is aqueous.
Claim 19
Dependent Claim
14 words
The method of claim 11 wherein said solution contains dilute hydrochloric or nitric acid.
Claim 20
Independent Claim
92 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal proximate to the surface of said silicon layer by ion implantation, with a dose of 10 12 to 5×10 14 atoms/cm 2 ; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 21
Independent Claim
92 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal proximate to the surface of said silicon layer by ion implantation, with a dose of 10 12 to 5×10 14 atoms/cm 2 ; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 22
Dependent Claim
14 words
The method of claim 16 wherein said refractory metal is Mo, Ta or W.
Claim 23
Independent Claim
90 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by sputtering, said refractory metal occurring in a layer less than 2 nm thick; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 24
Independent Claim
90 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by sputtering, said refractory metal occurring in a layer less than 2 nm thick; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 25
Dependent Claim
14 words
The method of claim 18 wherein said refractory metal is Mo, Ta or W.
Claim 26
Independent Claim
91 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by metal evaporation, said refractory metal occurring in a layer less than 2 nm thick; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 27
Independent Claim
91 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by metal evaporation, said refractory metal occurring in a layer less than 2 nm thick; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 28
Dependent Claim
14 words
The method of claim 20 wherein said refractory metal is Mo, Ta or W.
Claim 29
Independent Claim
103 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by exposing the surface of said silicon layer to a solution containing said refractory metal, said refractory metal occurring in a layer less than 2 nm thick; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 30
Independent Claim
103 words
A method for forming a titanium silicide layer on a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal on the surface of said silicon layer by exposing the surface of said silicon layer to a solution containing said refractory metal, said refractory metal occurring in a layer less than 2 nm thick; depositing a layer comprising titanium and silicon over said refractory metal; and heating said wafer to a temperature sufficient to substantially form the C54 phase of said titanium silicide layer from said layer comprising titanium and silicon, said temperature being less than about 700° C.
Claim 31
Dependent Claim
14 words
The method of claim 22 wherein said refractory metal is Mo, Ta or W.
Claim 32
Independent Claim
77 words
A method for forming a C54 phase titanium silicide layer overlying a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal proximate to the surface of said silicon layer by ion implantation with a dose of 10 12 to 5×10 14 atoms/cm 2 ; depositing a titanium layer overlying said silicon layer; and heating said wafer to a temperature sufficient to form said C54 phase titanium silicide layer from said titanium layer.
Claim 33
Independent Claim
77 words
A method for forming a C54 phase titanium silicide layer overlying a silicon layer on a semiconductor wafer, comprising the steps of: disposing a refractory metal proximate to the surface of said silicon layer by ion implantation with a dose of 10 12 to 5×10 14 atoms/cm 2 ; depositing a titanium layer overlying said silicon layer; and heating said wafer to a temperature sufficient to form said C54 phase titanium silicide layer from said titanium layer.
Claim 34
Dependent Claim
26 words
The method of claim 24 wherein the C54 phase of said titanium silicide layer is formed at a wafer temperature of less than about 700° C.
Claim 35
Dependent Claim
21 words
The method of claim 24 wherein said titanium layer is deposited to a thickness of between about 25 to 57.5 nm.
Claim 36
Dependent Claim
16 words
The method of claim 24 wherein said refractory metal is Mo, W, Ta, Nb, or Cr.
Claim 37
Dependent Claim
14 words
The method of claim 27 wherein said refractory metal is Mo, Ta, or W.
Claim 38
Dependent Claim
32 words
The method of claim 28 wherein said step of disposing said refractory metal is performed by ion implantation with an implant dose of about 10 13 to 10 14 atoms/cm 2 .
Claim 39
Dependent Claim
44 words
The method of claim 29 further comprising the step of annealing said wafer following said step of disposing a refractory metal and prior to said step of depositing a titanium layer, said annealing being at a wafer temperature between about 900° to 1000° C.
Claim 40
Dependent Claim
11 words
The method of claim 24 Wherein said refractory metal is Mo.
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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) | 1999-04-23 | 1999-10-23 | 2000-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-23 | 2003-10-23 | 2004-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-23 | 2007-10-23 | 2008-04-23 | $7700.00 | Window Closed / Lapsed |