US4056457A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of depositing low stress hafnium thin films
Assignee: RCA Corp
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Filing: 1976-09-20
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Granted: 1977-11-01
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Expires: 1996-09-20
Abstract
Abstract By radio frequency sputtering hafnium films on an alumina or sapphire substrate at high deposition rates and minimum substrate target bias, improved adhesion of the hafnium films to the substrate is obtained.
Inventors
- 👤 John Louis Vossen, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:52
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/06; C23C14/14; C23C14/18; C23C14/185
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
55 words
A method for depositing adherent films of hafnium metal on an alumina or sapphire substrate which comprises radio frequency vacuum sputtering a hafnium target in an inert gaseous plasma atmosphere at deposition rates of over 175 Angstroms per minute onto said substrate, said substrate being maintained at minimum bias with respect to said plasma atmosphere.
Claim 2
Independent Claim
55 words
A method for depositing adherent films of hafnium metal on an alumina or sapphire substrate which comprises radio frequency vacuum sputtering a hafnium target in an inert gaseous plasma atmosphere at deposition rates of over 175 Angstroms per minute onto said substrate, said substrate being maintained at minimum bias with respect to said plasma atmosphere.
Claim 3
Dependent Claim
32 words
A method according to claim 1 wherein sputtering is carried out in said plasma atmosphere of from about 60 to 100 millitorr, and about 1500 volts are applied to the hafnium target.
Claim 4
Dependent Claim
20 words
A method according to claim 1 wherein said plasma atmosphere comprises argon maintained at a pressure of about 80 millitorr.
Claim 5
Dependent Claim
19 words
A method according to claim 1 wherein the rate of deposition is maintained at over 500 angstroms per minute.
Claim 6
Dependent Claim
20 words
A composite comprising a layer of hafnium adhered to a sapphire substrate and deposited by the method of claim 1.
Claim 7
Independent Claim
101 words
A method of depositing adherent hafnium films on alumina or sapphire substrates by radio frequency sputtering which comprises: a. evacuating a vacuum chamber fitted for radio frequency sputtering of hafnium metal onto an alumina or sapphire substrate to a pressure of about 1 × 10 -7 torr, b. adding an inert gas to a pressure of from about 60 to about 100 millitorr, and c. applying a voltage of about 1500 volts to a hafnium deposition target, thereby sputtering hafnium at a deposition rate of over 175 angstroms per minute and at minimum substrate voltage with respect to the plasma atmosphere.
Claim 8
Independent Claim
101 words
A method of depositing adherent hafnium films on alumina or sapphire substrates by radio frequency sputtering which comprises: a. evacuating a vacuum chamber fitted for radio frequency sputtering of hafnium metal onto an alumina or sapphire substrate to a pressure of about 1 × 10 -7 torr, b. adding an inert gas to a pressure of from about 60 to about 100 millitorr, and c. applying a voltage of about 1500 volts to a hafnium deposition target, thereby sputtering hafnium at a deposition rate of over 175 angstroms per minute and at minimum substrate voltage with respect to the plasma atmosphere.
Claim 9
Dependent Claim
21 words
A method according to claim 6 wherein said inert gas is argon and said inert gas pressure is about 80 millitorr.
References Cited (Backward Citations)
US3647662A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-31 | 1981-05-02 | 1981-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-31 | 1985-05-02 | 1985-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-31 | 1989-05-02 | 1989-11-01 | $7700.00 | Window Closed / Lapsed |