US6022795A
Expired / Lapsed
US
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Salicide formation process
Assignee: United Microelectronics Corp
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Filing: 1998-05-07
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Granted: 2000-02-08
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Expires: 2018-05-07
Abstract
Abstract A method of making a semiconductor device including a MOS transistor provides an insulator formed on a semiconductor substrate and a gate electrode formed on the insulator. Source/drain regions are formed within the substrate on either side of the gate electrode. A layer of titanium is sputtered onto the semiconductor device, and a layer of titanium nitride is direct sputtered over the titanium layer using a titanium nitride target. The device is annealed at a first temperature to form a structure including titanium silicide on the polysilicon electrode, titanium silicide on the surface of the source/drain regions, unreacted titanium over the silicide regions, and titanium nitride over the unreacted metal. The unreacted titanium and titanium nitride are removed from the structure, and the structure is annealed at a higher temperature than the first temperature to form a lower resistivity titanium silicide.
Inventors
- 👤 Tung-Po Chen
- 👤 Hong-Tsz Pan
- 👤 Wen-Yi Hsieh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:22
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0212; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01308; H10D64/0131
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
89 words
A method of forming a self-aligned silicide structure comprising the steps of: forming a structure including a layer of titanium over a surface of a polysilicon gate electrode and over source/drain regions in a substrate; direct sputtering a layer of titanium nitride over the layer of titanium using a titanium nitride target material and in a nitrogen-free atmosphere; annealing the structure at a first temperature to form titanium silicide on the polysilicon gate electrode and titanium silicide on the source/drain regions; and removing the titanium nitride from the structure.
Claim 2
Independent Claim
89 words
A method of forming a self-aligned silicide structure comprising the steps of: forming a structure including a layer of titanium over a surface of a polysilicon gate electrode and over source/drain regions in a substrate; direct sputtering a layer of titanium nitride over the layer of titanium using a titanium nitride target material and in a nitrogen-free atmosphere; annealing the structure at a first temperature to form titanium silicide on the polysilicon gate electrode and titanium silicide on the source/drain regions; and removing the titanium nitride from the structure.
Claim 3
Dependent Claim
33 words
The method of claim 1, wherein a layer of unreacted titanium remains in the structure after annealing the structure at the first temperature and prior to the step of removing the titanium nitride.
Claim 4
Dependent Claim
29 words
The method of claim 1, further comprising the step of removing any unreacted titanium from the structure after annealing the structure at the first temperature to form titanium silicide.
Claim 5
Dependent Claim
36 words
The method of claim 3, further comprising the step of annealing the structure at a second temperature after removing the titanium nitride and any unreacted titanium, wherein the second temperature is greater than the first temperature.
Claim 6
Dependent Claim
29 words
The method of claim 1, wherein the direct sputtering of the layer of titanium nitride is carried out with the substrate held at a temperature of approximately 300° C.
Claim 7
Dependent Claim
25 words
The method of claim 1, wherein the substrate is held at a temperature of approximately 300° C. during the formation of the layer of titanium.
Claim 8
Dependent Claim
27 words
The method of claim 6, wherein the substrate is held at a temperature of approximately 300° C. during the direct sputtering of the layer of titanium nitride.
Claim 9
Dependent Claim
26 words
The method of claim 1, wherein the direct sputtering of the layer of titanium nitride is carried out with the substrate held at approximately room temperature.
Claim 10
Dependent Claim
22 words
The method of claim 1, wherein the substrate is held at approximately room temperature during the formation of the layer of titanium.
Claim 11
Dependent Claim
24 words
The method of claim 9, wherein the substrate is held at approximately room temperature during the direct sputtering of the layer of titanium nitride.
Claim 12
Dependent Claim
16 words
The method of claim 1, wherein the layer of titanium nitride is approximately 100 Å thick.
Claim 13
Independent Claim
145 words
A method of making a semiconductor device including a MOS transistor, the method of making the MOS transistor comprising the steps of: forming an insulator on a semiconductor substrate; forming a gate electrode on the insulator; forming source/drain regions within the substrate on either side of the gate electrode; direct sputtering a titanium layer on the semiconductor device; direct sputtering a layer of nitride, using a nitride target and in a nitrogen-free atmosphere, over the titanium layer; annealing the device at a first temperature to form a structure including titanium silicide on the polysilicon electrode, titanium silicide on the surface of the source/drain regions, unreacted titanium over the silicide regions, and titanium nitride over the unreacted titanium; removing unreacted titanium and titanium nitride from the structure; and annealing the structure at a higher temperature than the first temperature to form a lower resistivity titanium silicide.
Claim 14
Independent Claim
145 words
A method of making a semiconductor device including a MOS transistor, the method of making the MOS transistor comprising the steps of: forming an insulator on a semiconductor substrate; forming a gate electrode on the insulator; forming source/drain regions within the substrate on either side of the gate electrode; direct sputtering a titanium layer on the semiconductor device; direct sputtering a layer of nitride, using a nitride target and in a nitrogen-free atmosphere, over the titanium layer; annealing the device at a first temperature to form a structure including titanium silicide on the polysilicon electrode, titanium silicide on the surface of the source/drain regions, unreacted titanium over the silicide regions, and titanium nitride over the unreacted titanium; removing unreacted titanium and titanium nitride from the structure; and annealing the structure at a higher temperature than the first temperature to form a lower resistivity titanium silicide.
Claim 15
Dependent Claim
29 words
The method of claim 12, wherein the direct sputtering of the layer of titanium nitride is carried out with the substrate held at a temperature of approximately 300° C.
Claim 16
Dependent Claim
27 words
The method of claim 12, wherein the direct sputtering of the titanium layer is carried out with the substrate held at a temperature of approximately 300° C.
Claim 17
Dependent Claim
27 words
The method of claim 14, wherein the substrate is held at a temperature of approximately 300° C. during the direct sputtering of the layer of titanium nitride.
Claim 18
Dependent Claim
26 words
The method of claim 12, wherein the direct sputtering of the layer of titanium nitride is carried out with the substrate held at approximately room temperature.
Claim 19
Dependent Claim
24 words
The method of claim 12, wherein the direct sputtering of the titanium layer is carried out with the substrate held at approximately room temperature.
Claim 20
Dependent Claim
16 words
The method of claim 12, wherein the layer of titanium nitride is approximately 100 Å thick.
Claim 21
Independent Claim
76 words
A method of forming a self-aligned silicide structure comprising the steps of: forming a structure including a layer of titanium over a gate electrode and over source/drain regions in a substrate; direct sputtering a layer of titanium nitride over the layer of titanium using a titanium nitride target in an inert, nitrogen-free atmosphere; and annealing the structure at a first temperature to form titanium silicide on the polysilicon electrode and titanium silicide on the source/drain regions.
Claim 22
Independent Claim
76 words
A method of forming a self-aligned silicide structure comprising the steps of: forming a structure including a layer of titanium over a gate electrode and over source/drain regions in a substrate; direct sputtering a layer of titanium nitride over the layer of titanium using a titanium nitride target in an inert, nitrogen-free atmosphere; and annealing the structure at a first temperature to form titanium silicide on the polysilicon electrode and titanium silicide on the source/drain regions.
Claim 23
Dependent Claim
11 words
The method of claim 19, wherein the inert atmosphere comprises argon.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2003-02-07 | 2003-08-09 | 2004-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-02-07 | 2007-08-09 | 2008-02-08 | $3760.00 | Window Closed / Lapsed |
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