Patent US1636978A successfully refreshed from Google Patents.
Patent US5664316A successfully refreshed from Google Patents.
US5664316A
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Method of manufacturing magnetoresistive read transducer having a contiguous longitudinal bias layer
Assignee: International Business Machines Corp
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Filing: 1995-05-10
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Granted: 1997-09-09
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Expires: 2015-05-10
Abstract
Abstract A magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed over substantially only the central active region and in which a magnetic bias layers is formed in each passive end region. Each of the magnetic bias layers includes a layer of ferromagnetic material and a layer of antiferromagnetic material overlaying and in contact with the ferromagnetic layer to provide an exchange-coupled magnetic bias field. Each of the magnetic bias layers form an abutting junction having magnetic and electrically continuity with the MR layer to produce a longitudinal magnetic bias field in the transducer.
Inventors
- 👤 Mao-Min Chen
- 👤 Robert Edward Fontana
- 👤 Mohamad Towfik Krounbi
- 👤 Kenneth Ting-Yuan Kung
- 👤 James Hsi-Tang Lee
- 👤 Jyh-Shiliey Jerry Lo
- 👤 Ching Hwa Tsang
- 👤 Po-Kang Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:23
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3929; G11B5/3932; G11B5/399; G11B5/31; G11B5/3163; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49034; Y10T29/49036; Y10T29/49043; Y10T29/49044; Y10T29/49046
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
192 words
A method for manufacturing a magnetoresistive read transducer having end regions separated by a central active region comprising the steps of: depositing a first layer of ferromagnetic material on a substrate; forming a stencil which covers at least a portion of said first layer of ferromagnetic material which defines a central active region of said transducer; etching away portions of said first layer of magnetoresistive material not covered by said stencil to form a magnetoresistive element extending over said central active region of said transducer; depositing a second layer of ferromagnetic material over end regions of said transducer not covered by said stencil; and depositing a layer of antiferromagnetic material over said end regions of said transducer not covered by said stencil, said layer of antiferromagnetic material overlaying and in contact with said second layer of ferromagnetic material, said layers of antiferromagnetic and ferromagnetic material forming an exchange-coupled bias layer extending over said end regions of said transducer, said exchange-coupled bias layer in each of said end regions forming an abutting junction with one end of said magnetoresistive element, said exchange-coupled bias layers producing a longitudinal magnetic bias field in said transducer.
Claim 2
Independent Claim
192 words
A method for manufacturing a magnetoresistive read transducer having end regions separated by a central active region comprising the steps of: depositing a first layer of ferromagnetic material on a substrate; forming a stencil which covers at least a portion of said first layer of ferromagnetic material which defines a central active region of said transducer; etching away portions of said first layer of magnetoresistive material not covered by said stencil to form a magnetoresistive element extending over said central active region of said transducer; depositing a second layer of ferromagnetic material over end regions of said transducer not covered by said stencil; and depositing a layer of antiferromagnetic material over said end regions of said transducer not covered by said stencil, said layer of antiferromagnetic material overlaying and in contact with said second layer of ferromagnetic material, said layers of antiferromagnetic and ferromagnetic material forming an exchange-coupled bias layer extending over said end regions of said transducer, said exchange-coupled bias layer in each of said end regions forming an abutting junction with one end of said magnetoresistive element, said exchange-coupled bias layers producing a longitudinal magnetic bias field in said transducer.
Claim 3
Dependent Claim
22 words
The method as in claim 1 wherein said abutting junction comprises overlapping tapered portions of said magnetoresistive element and said bias layer.
Claim 4
Dependent Claim
23 words
The method as in claim 2 wherein the length of said overlapping junction is about five time the thickness of said magnetoresistive element.
Claim 5
Dependent Claim
29 words
The method as in claim 2 wherein the length of said overlapping junction is within the range of about three to five times the thickness of said magnetoresistive element.
Claim 6
Dependent Claim
18 words
The method as in claim 1 wherein said etch step comprises the use of a directional etching method.
Claim 7
Dependent Claim
15 words
The method as in claim 5 wherein said directional etching method comprises ion beam milling.
Claim 8
Dependent Claim
20 words
The method as in claim 5 wherein said directional etching method is carried out at an angle to said transducer.
Claim 9
Dependent Claim
19 words
The method as in claim 7 wherein said angle is within the range of about seventy to eighty degrees.
Claim 10
Dependent Claim
22 words
The method as in claim 7 wherein said transducer is rotated in a plane normal to said angle during said etching step.
Claim 11
Dependent Claim
13 words
The method as in claim 1 wherein said stencil comprises a photoresist material.
Claim 12
Dependent Claim
23 words
The method as in claim 10 wherein said photoresist material comprises a thin underlayer and a thick imaging layer overlaying said thin underlayer.
Claim 13
Dependent Claim
11 words
The method as in claim 11 wherein said underlayer is undercut.
Claim 14
Dependent Claim
30 words
The method as in claim 1 further comprising the step of depositing means for producing a transverse magnetic bias field in at least a portion of said central active region.
Claim 15
Dependent Claim
28 words
The method as in claim 13 wherein said means for producing a transverse magnetic bias field comprises a layer of soft magnetic material spaced from said magnetoresistive element.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-09-08 | 2001-03-10 | 2001-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-08 | 2005-03-10 | 2005-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-08 | 2009-03-10 | 2009-09-09 | $7700.00 | Window Closed / Lapsed |