US4847111A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma-nitridated self-aligned tungsten system for VLSI interconnections
Assignee: Raytheon Co
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Filing: 1988-06-30
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Granted: 1989-07-11
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Expires: 2008-06-30
Abstract
Abstract A process for forming a diffusion barrier on exposed silicon and polysilicon contacts of an integrated circuit including the step of chemically vapor depositing a layer of tungsten in a self-aligned manner on the exposed contact areas. The layer of tungsten is plasma nitridated to form a tungsten nitride layer and to partially form a tungsten silicide layer adjacent the contact areas. The formation of the tungsten silicide layer is completed by thermal annealing.
Inventors
- 👤 Yu C. Chow
- 👤 Kuan-Yang Liao
- 👤 Maw-Rong Chin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:11
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/20; H10D64/23; H10D64/251; H10D64/258; H10D64/259
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
52 words
A process for forming a diffusion barrier on exposed silicon and polysilicon contacts of an integrated circuit wafer, the process comprising the steps of: depositing a layer of tungsten on the exposed contact areas; and transforming the deposited layer of tungsten to form stacked, laterally co-extensive tungsten nitride and tungsten silicide layers.
Claim 2
Dependent Claim
52 words
A process for forming a diffusion barrier on exposed silicon and polysilicon contacts of an integrated circuit wafer, the process comprising the steps of: depositing a layer of tungsten on the exposed contact areas; and transforming the deposited layer of tungsten to form stacked, laterally co-extensive tungsten nitride and tungsten silicide layers.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein the step of depositing a layer of tungsten includes the step of chemically vapor depositing tungsten.
Claim 4
Dependent Claim
27 words
The process of claim 2 wherein the step of chemically vapor depositing tungsten includes the step of applying a gas mixture including silane, hydrogen, and tungsten hexafluoride.
Claim 5
Dependent Claim
24 words
The process of claim 3 wherein the step of chemically vapor depositing tungsten is performed at a temperature between 250° C. and 450° C.
Claim 6
Dependent Claim
27 words
The process of claim 1 wherein the step of transforming includes the steps of: nitridating the layer of tungsten; and heat treating the nitridated layer of tungsten.
Claim 7
Dependent Claim
16 words
The process of claim 5 wherein the step of nitridation includes the step of plasma nitridation.
Claim 8
Dependent Claim
19 words
The process of claim 5 wherein the step of heat treating includes the step of heating above 600° C.
Claim 9
Dependent Claim
67 words
A process for forming a diffusion barrier on exposed silicon and polysilicon contacts of an integrated circuit, the process comprising the steps: chemically vapor depositing a layer of tungsten in a self-aligned manner on the exposed contact areas in a deposition reactor; maintaining the wafer in the deposition reactor; and transforming the deposited layer of tungsten to form stacked, laterally co-extensive tungsten nitride and tungsten silicide layers.
Claim 10
Dependent Claim
67 words
A process for forming a diffusion barrier on exposed silicon and polysilicon contacts of an integrated circuit, the process comprising the steps: chemically vapor depositing a layer of tungsten in a self-aligned manner on the exposed contact areas in a deposition reactor; maintaining the wafer in the deposition reactor; and transforming the deposited layer of tungsten to form stacked, laterally co-extensive tungsten nitride and tungsten silicide layers.
Claim 11
Dependent Claim
27 words
The process of claim 8 wherein the step of chemically vapor depositing tungsten includes the step of applying a gas mixture including silane, hydrogen, and tungsten hexafluoride.
Claim 12
Dependent Claim
24 words
The process of claim 9 wherein the step of chemically vapor depositing tungsten is performed at a temperature between 250° C. and 450° C.
Claim 13
Dependent Claim
27 words
The process of claim 8 wherein the step of transforming includes the steps of: nitridating the layer of tungsten; and heat treating the nitridated layer of tungsten.
Claim 14
Dependent Claim
16 words
The process of claim 11 wherein the step of nitridation includes the step of plasma nitridation.
Claim 15
Dependent Claim
19 words
The process of claim 11 wherein the step of heat treating includes the step of heating above 600° C.
References Cited (Backward Citations)
US4676866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |