US4816425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polycide process for integrated circuits
Assignee: Texas Instruments Inc
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Filing: 1987-04-06
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Granted: 1989-03-28
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Expires: 2007-04-06
Abstract
Abstract A process for making a semiconductor integrated circuit which has electrodes, contacts and interconnects composed of a multilayer structure including a layer of polycrystalline silicon with an overlying layer of a refractory metal silicide such as MoSi 2 or WSi 2 . Adhesion of the metal silicide to the polysilicon is enhanced by forming a thin silicon oxide coating on the polysilicon before sputtering the metal silicide. The resulting structure has low resistance but retains the advantages of polysilicon on silicon.
Inventors
- 👤 Joe W. McPherson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:23
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/83; H10D64/00; H10D64/60; H10D64/62; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/44; H10W20/4451
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
60 words
A method of applying contact and interconnect material to a face of a semiconductor body comprising the steps of: applying a layer of polycrystalline silicon to the face: cleaning said layer with hydrofluoric acid; forming a very thin coating of silicon oxide on said layer; and thereafter applying a layer of molybdenum silicide over said polycrystalline silicon and silicon oxide.
Claim 2
Independent Claim
60 words
A method of applying contact and interconnect material to a face of a semiconductor body comprising the steps of: applying a layer of polycrystalline silicon to the face: cleaning said layer with hydrofluoric acid; forming a very thin coating of silicon oxide on said layer; and thereafter applying a layer of molybdenum silicide over said polycrystalline silicon and silicon oxide.
Claim 3
Dependent Claim
22 words
A method according to claim 1 wherein the oxide coating is formed by exposing the layer of polycrystalline silicon to nitric acid.
Claim 4
Dependent Claim
16 words
A method according to claim 1 wherein the layer of molybdenum silicide is applied by sputtering.
Claim 5
Dependent Claim
16 words
A method according to claim 1 wherein the layer of molybdenum silicide is applied by sputtering.
Claim 6
Dependent Claim
27 words
A method according to claim 4 wherein the step of sputtering breaks up the coating of oxide yet the oxide enhances adhesion of silicide to polycrystalline silicon.
Claim 7
Dependent Claim
23 words
A method according to claim 1 including the step of doping the layer of polycrystalline silicon before applying the layer of molybdenum silicide.
Claim 8
Dependent Claim
23 words
A method according to claim 1 including the step of annealing the layer of molybdenum silicide to create a polycrystalline low resistance material.
Claim 9
Dependent Claim
22 words
The method according to claim 1 wherein tungsten silicide rather than molybdenum silicide is applied over said polycrystalline silicon and silicon oxide.
Claim 10
Dependent Claim
16 words
The method according to claim 8 wherein the layer of tungsten silicide is applied by sputtering.
References Cited (Backward Citations)
US4128670A
Cited
US4276557A
Cited
US4329706A
Cited
US4228212A
Cited
US4337476A
Cited
US4322453A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |