Patent US4749459A successfully refreshed from Google Patents.
US4749459A
Expired / Lapsed
US
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Method for manufacturing a thin film magnetic recording medium
Assignee: WD Media LLC
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Filing: 1986-03-10
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Granted: 1988-06-07
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Expires: 2006-03-10
Abstract
Abstract A film of magnetic recording media is formed by sputtering an alloy of cobalt and platinum onto a substrate. The sputtering takes place in a chamber containing argon and nitrogen. The magnetic coercivity of the resulting film is controlled by varying the concentration of nitrogen in the sputtering chamber. By using this technique, the film coercivity is controlled without varying other important parameters such as the saturation magnetization.
Inventors
- 👤 Tsutomu T. Yamashita
- 👤 Ching-Cheng Shir
- 👤 Tu Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:30
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/0021; C23C14/0036; G; G11; G11B; G11B5/00; G11B5/84; G11B5/851
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
112 words
A method for manufacturing a film of recording media comprising the steps of: sputtering an alloy film onto a substrate, said alloy comprising platinum and cobalt; controlling the coercivity of the film by introducing nitrogen into the sputtering chamber, the concentration of said nitrogen in said sputtering chamber being less than 1%, the coercivity of the resulting film decreasing as the amount of nitrogen introduced into said sputtering chamber increases, the coercivity of the resulting film being greater than about 600 Oe; and limiting the amount of oxygen in said sputtering chamber so that the concentration of oxygen in said sputtering chamber is insufficient to significantly affect the coercivity of said film.
Claim 2
Independent Claim
112 words
A method for manufacturing a film of recording media comprising the steps of: sputtering an alloy film onto a substrate, said alloy comprising platinum and cobalt; controlling the coercivity of the film by introducing nitrogen into the sputtering chamber, the concentration of said nitrogen in said sputtering chamber being less than 1%, the coercivity of the resulting film decreasing as the amount of nitrogen introduced into said sputtering chamber increases, the coercivity of the resulting film being greater than about 600 Oe; and limiting the amount of oxygen in said sputtering chamber so that the concentration of oxygen in said sputtering chamber is insufficient to significantly affect the coercivity of said film.
Claim 3
Dependent Claim
26 words
The method of claim 1 further comprising the step of introducing oxygen into the sputtering chamber, the oxygen also varying the coercivity of the resulting film.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein said nitrogen has a partial pressure between 10 -4 and 10 -7 torr.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein said step of introducing nitrogen comprises the step of introducing a gaseous compound comprising nitrogen, said gaseous compound decomposing during sputtering.
Claim 6
Independent Claim
103 words
A method for manufacturing a film of magnetic recording media comprising the steps of: sputtering an alloy film onto a substrate, said alloy comprising platinum and cobalt; and controlling the coercivity of said alloy by introducing oxygen into the sputtering chamber, the concentration of oxygen in said sputtering chamber being less than about 1%, the coercivity of the resulting film varying in response to the amount of oxygen introduced into said sputtering chamber, the coercivity of the resulting film being reduced as the amount of oxygen in said sputtering chamber increases, the coercivity of the resulting film being greater than about 600 Oe.
Claim 7
Independent Claim
103 words
A method for manufacturing a film of magnetic recording media comprising the steps of: sputtering an alloy film onto a substrate, said alloy comprising platinum and cobalt; and controlling the coercivity of said alloy by introducing oxygen into the sputtering chamber, the concentration of oxygen in said sputtering chamber being less than about 1%, the coercivity of the resulting film varying in response to the amount of oxygen introduced into said sputtering chamber, the coercivity of the resulting film being reduced as the amount of oxygen in said sputtering chamber increases, the coercivity of the resulting film being greater than about 600 Oe.
Claim 8
Dependent Claim
20 words
The method of claim 5 wherein said oxygen is introduced into the sputtering chamber in the form of water vapor.
Claim 9
Dependent Claim
18 words
The method of claim 6 wherein said water vapor has a partial pressure less than 10 -4 torr.
Claim 10
Dependent Claim
27 words
The method of claim 5 wherein said step of introducing oxygen comprises the step of introducing a gaseous compound comprising oxygen, said gaseous compound decomposing during sputtering.
Claim 11
Independent Claim
115 words
A method for manufacturing a film of recording media comprising the steps of: sputtering an alloy film onto a substrate, said alloy film having an intrinsic coercivity greater than about 600 Oe; controlling the coercivity of said film by introducing a selected gas into the sputtering chamber, the coercivity of said film decreasing as the amount of said selected gas introduced in said sputtering chamber increases, wherein said selected gas comprises oxygen or nitrogen and has a concentration less than 1%; and limiting the amount of oxygen in said sputtering chamber so that the presence of oxygen in said sputtering chamber does not cause said film to exhibit a coercivity less than about 600 Oe.
Claim 12
Independent Claim
115 words
A method for manufacturing a film of recording media comprising the steps of: sputtering an alloy film onto a substrate, said alloy film having an intrinsic coercivity greater than about 600 Oe; controlling the coercivity of said film by introducing a selected gas into the sputtering chamber, the coercivity of said film decreasing as the amount of said selected gas introduced in said sputtering chamber increases, wherein said selected gas comprises oxygen or nitrogen and has a concentration less than 1%; and limiting the amount of oxygen in said sputtering chamber so that the presence of oxygen in said sputtering chamber does not cause said film to exhibit a coercivity less than about 600 Oe.
Claim 13
Dependent Claim
12 words
The method of claim 9 wherein said alloy is iron-based or cobalt-based.
Claim 14
Dependent Claim
19 words
The method of claim 9 wherein the partial pressure of said selected gas is less than 10 -4 torr.
Claim 15
Dependent Claim
24 words
The method of claim 1 or 5 wherein said alloy includes another metal, said alloy having an intrinsic coercivity greater than about 650 Oe.
Claim 16
Dependent Claim
17 words
The method of claim 1 or 5 wherein the gas in said sputtering chamber comprises mostly argon.
Claim 17
Dependent Claim
15 words
The method of claim 1 or 5 wherein said alloy is at least 5% platinum.
Claim 18
Dependent Claim
18 words
The method of claim 1 or 5 wherein said alloy is sputtered onto a layer of nonferromagnetic metal.
Claim 19
Dependent Claim
19 words
The method of claim 1 or 5 wherein said alloy is sputtered onto a layer of electrically insulating material.
Claim 20
Dependent Claim
28 words
The method of claim 1 or 9 wherein said step of limiting the amount of oxygen is accomplished by limiting the concentration of water vapor in said atmosphere.
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) | 1991-06-07 | 1991-12-07 | 1992-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-07 | 1995-12-07 | 1996-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-07 | 1999-12-07 | 2000-06-07 | $7700.00 | Window Closed / Lapsed |