Patent US4997539A successfully refreshed from Google Patents.
US4997539A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for producing a magnetic recording medium
Assignee: Mitsubishi Chemical Corp
•
Filing: 1989-07-12
•
Granted: 1991-03-05
•
Expires: 2009-07-12
Abstract
Abstract A method for producing a magnetic recording medium, which comprises forming, by sputtering, a thin undercoating layer and a thin cobalt alloy magnetic layer sequentially on a substrate, wherein an intermediate electrode is provided in the vicinity of the target to enclose at least 1/2 of the circumference of the sputter erosion end of the target, and at least one of the undercoating layer and the cobalt alloy magnetic layer is formed under such condition that a positive potential relative to the substrate and the grounded portion of the main body of the layer-forming apparatus, is applied to the intermediate electrode.
Inventors
- 👤 Kazunaga Komizo
- 👤 Masatoshi Ichikawa
- 👤 Takeshi Sakuma
- 👤 Fumiaki Yokoyama
- 👤 Yukio Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:44
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/851; G11B5/8404
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
101 words
A method for producing a magnetic recording medium, which comprises forming, by sputtering, a thin undercoating layer and a thin cobalt alloy magnetic layer sequentially on a substrate, wherein an intermediate electrode is provided in the vicinity of the target to enclose at least 1/2 of the circumference of the sputter erosion end of the target, and at least one of the undercoating layer and the cobalt alloy magnetic layer is formed under such condition that a positive potential relative to the substrate and the grounded portion of the main body of the layer-forming apparatus, is applied to the intermediate electrode.
Claim 2
Independent Claim
101 words
A method for producing a magnetic recording medium, which comprises forming, by sputtering, a thin undercoating layer and a thin cobalt alloy magnetic layer sequentially on a substrate, wherein an intermediate electrode is provided in the vicinity of the target to enclose at least 1/2 of the circumference of the sputter erosion end of the target, and at least one of the undercoating layer and the cobalt alloy magnetic layer is formed under such condition that a positive potential relative to the substrate and the grounded portion of the main body of the layer-forming apparatus, is applied to the intermediate electrode.
Claim 3
Dependent Claim
70 words
The method according to claim 1, wherein at least a part of the intermediate electrode is located between a position distanced by 1/3 of the distance between the surface of the target and the surface of the substrate, from the surface of the target in a direction towards the substrate, and a position distanced by 30 mm from the surface of the target in a direction away from the substrate.
Claim 4
Dependent Claim
70 words
The method according to claim 1, wherein at least a part of the intermediate electrode is located between a position distanced by 1/4 of the distance between the surface of the target and the surface of the substrate, from the surface of the target in a direction towards the substrate, and a position distanced by 20 mm from the surface of the target in a direction away from the substrate.
Claim 5
Dependent Claim
40 words
The method according to claim 1, wherein the intermediate electrode is located between the circumference of the sputter erosion end of the target and a position distanced by 200 mm from said circumference outwardly in the plane of the target.
Claim 6
Dependent Claim
40 words
The method according to claim 1, wherein the intermediate electrode is located between the circumference of the sputter erosion end or the target and a position distanced by 150 mm from said circumference outwardly in the plane of the target.
Claim 7
Dependent Claim
35 words
The method according to claim 1, wherein the intermediate electrode is located between the circumference of the target and a position distanced by 120 mm from said circumference outwardly in the plane of the target.
Claim 8
Dependent Claim
15 words
The method according to claim 1, wherein the undercoating layer is formed under said condition.
Claim 9
Dependent Claim
17 words
The method according to claim 1, wherein the cobalt alloy magnetic layer is formed under said condition.
Claim 10
Dependent Claim
22 words
The method according to claim 1, wherein the undercoating layer and the cobalt alloy magnetic layer are sequentially formed under said condition.
Claim 11
Dependent Claim
15 words
The method according to claim 1, wherein the undercoating layer is a thin chromium layer.
Claim 12
Dependent Claim
19 words
The method according to claim 1, wherein the cobalt alloy magnetic layer is a thin cobalt-chromium alloy magnetic layer.
Claim 13
Dependent Claim
19 words
The method according to claim 1, wherein the cobalt alloy magnetic layer is a thin cobalt-nickel alloy magnetic layer.
Claim 14
Dependent Claim
19 words
The method according to claim 1, wherein the cobalt alloy magnetic layer is a thin cobalt-chromium-tantalum alloy magnetic layer.
Claim 15
Dependent Claim
23 words
The method according to claim 1, wherein the undercoating layer is a chromium layer having a thickness of from 50 to 3,000 Å.
Claim 16
Dependent Claim
21 words
The method according to claim 1, wherein a positive potential of at most 1,000 V is applied to the intermediate electrode.
Claim 17
Dependent Claim
22 words
The method according to claim 1, wherein a positive potential of from 50 to 500 V is applied to the intermediate electrode.
Claim 18
Dependent Claim
29 words
The method according to claim 1, wherein a negative bias voltage relative to the rounded portion of the main body of the layer-forming apparatus is applied to the substrate.
Claim 19
Dependent Claim
34 words
The method according to claim 1, wherein a negative bias voltage of at most -1,000 V relative to the grounded portion of the main body of the layer-forming apparatus is applied to the substrate.
Claim 20
Dependent Claim
35 words
The method according to claim 1, wherein a negative bias voltage of from -50 to -500 V relative to the grounded portion of the main body of the layer-forming apparatus is applied to the substrate.
References Cited (Backward Citations)
US3410775A
Cited
US4094764A
Cited
US4427524A
Cited
JPS5916975A
Cited
US4412907A
Cited
US4784739A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |