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US5874353A
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Method of forming a self-aligned silicide device
Assignee: United Microelectronics Corp
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Filing: 1997-09-11
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Granted: 1999-02-23
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Expires: 2017-09-11
Abstract
Abstract A method of forming self-aligned silicide devices which includes providing a silicon substrate having shallow trench isolation regions for defining a device area formed therein; then, forming sequentially a gate oxide layer, a polysilicon layer, a first titanium nitride layer, a titanium silicide layer, a second titanium nitride layer and a silicon nitride layer over the substrate. After a gate electrode is etched out from the above layers, a titanium layer is deposited over the device, and then a self-aligned titanium silicide layer is formed using a heating process. The use of a titanium silicide layer having protective top and bottom titanium nitride layers, compared with a single tungsten silicide layer in a conventional method, provides for a self-aligned silicide device having a rather low gate resistance; being free from narrow width effect of a titanium self-aligned silicide layer; is applicable to self-aligned contact window processes, and avoids the cross-diffusion of doped ions in the polysilicon layer of a dual gate electrode having a tungsten polycide layer.
Inventors
- 👤 Tony Lin
- 👤 Water Lur
- 👤 Shih-Wei Sun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:52
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0212; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01308; H10D64/0131; H10D64/01312; H10D64/60; H10D64/66; H10D64/661; H10D64/662; H10D64/664
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
183 words
A method of forming a self-aligned silicide device, comprising: providing a silicon substrate having shallow trench isolation regions therein which define a device area; forming a gate oxide layer over the substrate and the shallow trench isolation regions; forming a polysilicon layer over the gate oxide layer; forming a first titanium nitride layer over the polysilicon layer; forming a titanium silicide layer over the first titanium nitride layer; forming a second titanium nitride layer over the titanium silicide layer; forming a silicon nitride layer over the second titanium nitride layer; patterning and then etching the polysilicon layer, the first titanium nitride layer, the titanium silicide layer, the second titanium nitride layer and the silicon nitride layer to form a stacked composite gate electrode, and expose portions of the substrate in the device area; forming spacers around the gate electrode; depositing a titanium layer over the spacers and the exposed portions of the substrate; heating the titanium layer and the substrate causing them to react and form a self-aligned titanium silicide layer; and removing any unreacted portion of the titanium layer using wet etching.
Claim 2
Independent Claim
183 words
A method of forming a self-aligned silicide device, comprising: providing a silicon substrate having shallow trench isolation regions therein which define a device area; forming a gate oxide layer over the substrate and the shallow trench isolation regions; forming a polysilicon layer over the gate oxide layer; forming a first titanium nitride layer over the polysilicon layer; forming a titanium silicide layer over the first titanium nitride layer; forming a second titanium nitride layer over the titanium silicide layer; forming a silicon nitride layer over the second titanium nitride layer; patterning and then etching the polysilicon layer, the first titanium nitride layer, the titanium silicide layer, the second titanium nitride layer and the silicon nitride layer to form a stacked composite gate electrode, and expose portions of the substrate in the device area; forming spacers around the gate electrode; depositing a titanium layer over the spacers and the exposed portions of the substrate; heating the titanium layer and the substrate causing them to react and form a self-aligned titanium silicide layer; and removing any unreacted portion of the titanium layer using wet etching.
Claim 3
Dependent Claim
18 words
The method of claim 1, wherein said forming a polysilicon layer includes using low pressure chemical vapor deposition.
Claim 4
Dependent Claim
17 words
The method of claim 1, wherein said forming a first titanium nitride layer includes using reactive sputtering.
Claim 5
Dependent Claim
94 words
The method of claim 1, wherein said forming a titanium silicide layer and said forming a second titanium nitride layer include the following operations: depositing a titanium layer over the first titanium nitride layer; and passing gaseous nitrogen and then performing rapid thermal processing to cause silicon to react with portions of the titanium layer to form the titanium silicide layer over the first titanium nitride layer, and to cause the nitrogen to react with a remaining portion of the titanium layer to form the second titanium nitride layer over the titanium silicide layer.
Claim 6
Dependent Claim
25 words
The method of claim 1, wherein said forming a titanium silicide layer includes depositing titanium over the first titanium nitride layer using chemical vapor deposition.
Claim 7
Dependent Claim
25 words
The method of claim 1, wherein said forming a titanium silicide layer includes depositing titanium over the first titanium nitride layer using physical vapor deposition.
Claim 8
Dependent Claim
26 words
The method of claim 1, wherein said forming a second titanium nitride layer includes depositing titanium nitride over the titanium silicide layer using chemical vapor deposition.
Claim 9
Dependent Claim
26 words
The method of claim 1, wherein said forming a second titanium nitride layer includes depositing titanium nitride over the titanium silicide layer using physical vapor deposition.
Claim 10
Dependent Claim
19 words
The method of claim 1, wherein said forming a silicon nitride layer includes using low pressure chemical vapor deposition.
Claim 11
Dependent Claim
19 words
The method of claim 1, wherein said heating the titanium layer and the substrate includes using rapid thermal processing.
Claim 12
Dependent Claim
21 words
The method of claim 1, wherein said forming a polysilicon layer includes depositing polysilicon to a thickness of about 1000-3500 Å.
Claim 13
Dependent Claim
24 words
The method of claim 1, wherein said forming a first titanium nitride layer includes depositing titanium nitride to a thickness of about 5-50 Å.
Claim 14
Dependent Claim
23 words
The method of claim 1, wherein said forming a silicon nitride layer includes depositing silicon nitride to a thickness of about 300-2000 Å.
Claim 15
Dependent Claim
13 words
The method of claim 1, wherein said forming spacers includes depositing silicon nitride.
Claim 16
Dependent Claim
13 words
The method of claim 1, wherein said forming spacers includes depositing silicon oxide.
Claim 17
Independent Claim
72 words
A method of forming a composite electrode, comprising: forming a first titanium nitride layer over a polysilicon layer; forming a titanium silicide layer over the first titanium nitride layer; forming a second titanium nitride layer over the titanium silicide layer; and forming a silicon nitride layer over the second titanium nitride layer, wherein the polysilicon layer, first titanium nitride layer, titanium silicide layer and silicon nitride layer together form a composite electrode.
Claim 18
Independent Claim
72 words
A method of forming a composite electrode, comprising: forming a first titanium nitride layer over a polysilicon layer; forming a titanium silicide layer over the first titanium nitride layer; forming a second titanium nitride layer over the titanium silicide layer; and forming a silicon nitride layer over the second titanium nitride layer, wherein the polysilicon layer, first titanium nitride layer, titanium silicide layer and silicon nitride layer together form a composite electrode.
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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) | 2002-02-22 | 2002-08-24 | 2003-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-02-22 | 2006-08-24 | 2007-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-02-22 | 2010-08-24 | 2011-02-23 | $7700.00 | Window Closed / Lapsed |