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US4874720A
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Method of making a metal-gate MOS VLSI device
Assignee: Texas Instruments Inc
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Filing: 1987-12-21
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Granted: 1989-10-17
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Expires: 2007-12-21
Abstract
Abstract A simplified process for metal gate and contact/interconnect systems for MOS VLSI devices employs a refractory metal structure for the gate, including a thick layer of tungsten alone, with stress and adhesion controlled by the deposition conditions. The metal gate receives sidewall oxide spacers during a metal-cladding operation for the source/drain areas. Contacts to the source/drain region include a molybdenum/tungsten stack and a top layer of gold.
Inventors
- 👤 James M. McDavid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:53
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/66; H10D64/665; H10D62/00; H10D62/80; H10D62/83; H10D64/62; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/44; H10W20/4403; H10W20/4437; H10W20/4441; Y; Y10; Y10S; Y10S148/00; Y10S148/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
210 words
A method of making a gate, a contact and interconnect structure in a process for manufacture of MOS integrated circuits, comprising the steps of: forming a metal gate on a face of a silicon body by applying a layer of tungsten overlying and adhered to a thin layer of silicon oxide on said face, and applying a coating of oxide on the sidewalls of said gate; forming heavily-doped source/drain regions in said face, said source/drain regions being self-aligned with said oxide on the sidewalls of the metal gate, forming selectively a tungsten metal layer on the surface of said source/drain regions self-aligned with said oxide on the sidewalls of the metal gate, forming a thick deposited insulator coating on said face over said metal gate and over said tungsten metal layer and source/drain regions, applying a metal contact and interconnect strip extending along said face overlying said insulator coating and extending into a contact hole in said insulator coating to make electrical connection to said tungsten metal layer, including: first applying a layer of molybdenum over said tungsten layer in said contact hole and over said insulator coating, and thereafter applying a thicker layer of tungsten over said molybdenum and a layer of gold over said thicker layer of tungsten.
Claim 2
Independent Claim
210 words
A method of making a gate, a contact and interconnect structure in a process for manufacture of MOS integrated circuits, comprising the steps of: forming a metal gate on a face of a silicon body by applying a layer of tungsten overlying and adhered to a thin layer of silicon oxide on said face, and applying a coating of oxide on the sidewalls of said gate; forming heavily-doped source/drain regions in said face, said source/drain regions being self-aligned with said oxide on the sidewalls of the metal gate, forming selectively a tungsten metal layer on the surface of said source/drain regions self-aligned with said oxide on the sidewalls of the metal gate, forming a thick deposited insulator coating on said face over said metal gate and over said tungsten metal layer and source/drain regions, applying a metal contact and interconnect strip extending along said face overlying said insulator coating and extending into a contact hole in said insulator coating to make electrical connection to said tungsten metal layer, including: first applying a layer of molybdenum over said tungsten layer in said contact hole and over said insulator coating, and thereafter applying a thicker layer of tungsten over said molybdenum and a layer of gold over said thicker layer of tungsten.
Claim 3
Dependent Claim
28 words
A method according to claim 1 wherein said step of forming source/drain regions includes forming shallow regions self-aligned with said metal gate before said sidewall oxide is applied.
Claim 4
Dependent Claim
19 words
A method according to claim 1 wherein said body is P type, and said source/drain regions are N+ type.
Claim 5
Dependent Claim
27 words
A method according to claim 1 wherein said layer of tungsten of the metal gate is much thicker than said layer of molybdenum of the metal contact.
Claim 6
Dependent Claim
16 words
A method according to claim 1 in which said making includes making a field effect transistor.
Claim 7
Independent Claim
167 words
A method of making a gate, contact and interconnect structure in a process for manufacture of MOS integrated circuits, comprising the steps of: forming a metal gate on a face of a silicon body by applying a layer of tungsten overlying and adhered to a thin layer of silicon oxide on said face, and applying a coating of oxide on the sidewalls of said gate; forming heavily-doped source/drain regions in said face, said source/drain regions being self-aligned with said oxide on the sidewalls of the metal gate, forming selectively a tungsten metal layer on the surface of said source/drain regions self-aligned with said oxide on the sidewalls of the metal gate, forming a thick deposited insulaator coating on said face over said metal gate and over said tungsten metal layer and source/drains regions, applying a metal contact and interconnect strip extending along said face overlying said insulator coating and extending into a contact hole in said insulator coating to make electrical connection to said tungsten metal layer.
Claim 8
Independent Claim
167 words
A method of making a gate, contact and interconnect structure in a process for manufacture of MOS integrated circuits, comprising the steps of: forming a metal gate on a face of a silicon body by applying a layer of tungsten overlying and adhered to a thin layer of silicon oxide on said face, and applying a coating of oxide on the sidewalls of said gate; forming heavily-doped source/drain regions in said face, said source/drain regions being self-aligned with said oxide on the sidewalls of the metal gate, forming selectively a tungsten metal layer on the surface of said source/drain regions self-aligned with said oxide on the sidewalls of the metal gate, forming a thick deposited insulaator coating on said face over said metal gate and over said tungsten metal layer and source/drains regions, applying a metal contact and interconnect strip extending along said face overlying said insulator coating and extending into a contact hole in said insulator coating to make electrical connection to said tungsten metal layer.
Claim 9
Dependent Claim
28 words
A method according to claim 6 wherein said sstep of forming source/drain regions includes forming shallow regions selfaligned with said metal gate before said sidewall oxide is applied.
Claim 10
Dependent Claim
18 words
A method accordin gto claim 6 wherein said body is P type, and said source/drain regions are N+type.
Claim 11
Dependent Claim
16 words
A method according to claim 6 in which said making includes making a field effect transistor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |