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US4239587A
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Method of manufacturing a thin-film magnetic head with a nickel-iron pattern having inclined edges
Assignee: US Philips Corp
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Filing: 1978-08-18
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Granted: 1980-12-16
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Expires: 1998-08-18
Abstract
Abstract In the electrodeposition of nickel-iron alloy layers during the manufacture of a thin-film magnetic head it is ensured that the nickel-iron alloy layer has a top layer having a higher iron content than the iron content of the remainder of the nickel-iron alloy layer. Since this top layer etches more rapidly than the remainder of the layer, the nickel-iron alloy layer itself becomes sloped during etching, this sloping configuration presents great advantages in the subsequent coating with a layer of silicon dioxide.
Inventors
- 👤 Gerrit J. Koel
- 👤 Lambertus Postma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:56
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3163
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
77 words
A method of manufacturing a thin-film magnetic head, the method including the steps of forming a layer of a nickel-iron alloy on a substrate, forming a photoresist pattern over the nickel-iron alloy layer, and chemically etching the nickel-iron layer so as to form a pattern having sloping sides, wherein a top thickness of the nickel-iron layer remote from the substrate has a higher iron content than the iron content of the remainder of the nickel-iron alloy layer.
Claim 2
Independent Claim
77 words
A method of manufacturing a thin-film magnetic head, the method including the steps of forming a layer of a nickel-iron alloy on a substrate, forming a photoresist pattern over the nickel-iron alloy layer, and chemically etching the nickel-iron layer so as to form a pattern having sloping sides, wherein a top thickness of the nickel-iron layer remote from the substrate has a higher iron content than the iron content of the remainder of the nickel-iron alloy layer.
Claim 3
Dependent Claim
61 words
A method as claimed in claim 1, characterized in that the nickel-iron layer is deposited on the substrate in an electroplating bath, a top layer having a higher iron content than the iron content of the remainder of the nickel-iron alloy layer being formed by reducing the voltage applied in the electroplating bath during the last phase of the deposition process.
Claim 4
Dependent Claim
31 words
A method as claimed in claim 1 or claim 2, characterized in that the nickel-iron layer is etched in an etching bath comprising a strong acid, hydrogen peroxide and hydrogen fluoride.
References Cited (Backward Citations)
US3808070A
Cited
US3892606A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-16 | 1984-06-16 | 1984-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-16 | 1988-06-16 | 1988-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-16 | 1992-06-16 | 1992-12-16 | $7700.00 | Window Closed / Lapsed |