WO1995014991A1 - Tetes magnetiques a couche mince comportant des sous-couches minces en nickel - Google Patents

Tetes magnetiques a couche mince comportant des sous-couches minces en nickel Download PDF

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Publication number
WO1995014991A1
WO1995014991A1 PCT/US1993/011571 US9311571W WO9514991A1 WO 1995014991 A1 WO1995014991 A1 WO 1995014991A1 US 9311571 W US9311571 W US 9311571W WO 9514991 A1 WO9514991 A1 WO 9514991A1
Authority
WO
WIPO (PCT)
Prior art keywords
seed layer
thin film
nickel seed
nickel
magnetic
Prior art date
Application number
PCT/US1993/011571
Other languages
English (en)
Inventor
Frank E. Stageberg
Mark S. Miller
Kenneth P. Ash
Original Assignee
Seagate Technology, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Seagate Technology, Inc. filed Critical Seagate Technology, Inc.
Priority to DE69318042T priority Critical patent/DE69318042T2/de
Priority to SG1996008482A priority patent/SG46693A1/en
Priority to EP94903341A priority patent/EP0730774B1/fr
Priority to US08/190,090 priority patent/US5666250A/en
Priority to JP51502795A priority patent/JP3539732B2/ja
Priority to PCT/US1993/011571 priority patent/WO1995014991A1/fr
Priority claimed from SG1996008482A external-priority patent/SG46693A1/en
Priority to US08/188,078 priority patent/US6125010A/en
Publication of WO1995014991A1 publication Critical patent/WO1995014991A1/fr
Priority to HK98110570A priority patent/HK1010069A1/xx

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3109—Details
    • G11B5/313—Disposition of layers
    • G11B5/3143—Disposition of layers including additional layers for improving the electromagnetic transducing properties of the basic structure, e.g. for flux coupling, guiding or shielding
    • G11B5/3146—Disposition of layers including additional layers for improving the electromagnetic transducing properties of the basic structure, e.g. for flux coupling, guiding or shielding magnetic layers
    • G11B5/3153—Disposition of layers including additional layers for improving the electromagnetic transducing properties of the basic structure, e.g. for flux coupling, guiding or shielding magnetic layers including at least one magnetic thin film coupled by interfacing to the basic magnetic thin film structure
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3109—Details
    • G11B5/3113—Details for improving the magnetic domain structure or avoiding the formation or displacement of undesirable magnetic domains
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3163—Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers

Definitions

  • the present invention relates to the fabrication of thin film heads for data storage systems. More particularly, the invention relates to the deposition of a nickel seed layer adjacent to the magnetic core of a thin film magnetic head, to reduce the effects of read instability.
  • Thin film magnetic read/write heads are used for magnetically reading and writing information on a magnetic storage medium which moves relative to the head, such as a magnetic disc.
  • a thin film magnetic head comprises a pair of “yokes” and “poles” which form the magnetic core of the head. Electrical conductors (or coils) pass between the core and are used for both reading and writing information onto the magnetic storage medium.
  • Electrical conductors or coils
  • electrical current is caused to flow through the coils generating a magnetic field in the core.
  • a gap region occupies a small space between two pole tips of the magnetic core.
  • the write current in the coils causes magnetic flux to span the gap region. This magnetic flux is then used to impress a magnetic field upon a storage medium producing a magnetic transition, which is then recorded.
  • the magnetic head and the storage medium also move relative to one another, causing magnetic flux to link through the coils. Electrical signals in the coils may be sensed with electric circuitry which enable the recovery of information stored on the magnetic medium.
  • the magnetic core serves as a link between the magnetic flux emanating from the transitions in the recording medium and the coils. In doing so, the magnetization of the core changes to reflect signal flux variations.
  • the changing magnetic state of the core is characterized by either magnetic rotation or domain wall motion. In some cases, excitation of the write signal can cause domain walls in the core to move irreversibly.
  • the core may be left with undesirable domain patterns. More particularly, the core may be unable to relax back to a stable magnetic state.
  • a stable magnetic state exists when the magnetic domains are oriented in an easy axis direction.
  • Particular domain patterns such as vertical walls in the pole tip region, are associated with a high degree of magnetic instability during the readback.
  • the inability of a magnetic head to return to a stable relaxed state may be caused by defects such as scratches, local stresses caused by the deposition process, or in homgeneities in composition of the core material in the head. In any case, if the domain patterns of the head vary significantly from the "desirable" relaxed magnetization state, the performance of the head is compromised.
  • head wiggle is a distortion of the read signal. The distortion primarily appears as noise on the trailing edge of the readback signal.
  • the present invention relates to the enhanced performance of a thin film head by minimizing the effects of read instability.
  • the invention provides an improved thin film head and a method of fabricating the same. Specifically, each yoke/pole structure that forms the magnetic core is deposited on a pure nickel seed layer. The presence of the nickel seed layer adjacent to the magnetic core structure of the thin film head exerts a -3- magnetic force on the core. This magnetic force pushes the head into a stable read state after a write excitation. The thin film magnetic head with reinforcing nickel seed layers is less likely to experience domain wall "Barkhausen" jumps in the readback. The result is a magnetic head with a significant improvement in read performance.
  • Figure 1 is a plan view of a thin film magnetic read/write head
  • Figure 2 is a plan view of a prior art thin film magnetic read/write head exhibiting a unstable magnetic domain pattern
  • Figure 3 is a plan view of a thin film magnetic read/write head exhibiting a stable magnetic domain pattern
  • Figure 4 is a cross-sectional view of a thin film magnetic read/write head made in accordance with the present invention as it appears on a slider;
  • Figure 5 is a cross-sectional view of the fabrication process of a thin film head made in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • the present invention is directed to an improved thin film magnetic head and method of fabricating the same.
  • the four main elements of a thin film head in the order in which they are deposited, are the bottom magnetic yoke/pole, the flux gap material which provides spacing between the yoke/poles, one or more levels of electrical conducting coils interposed within insulation layers and a top magnetic yoke/pole.
  • the present invention is directed to a seed layer comprised of nickel under each magnetic yoke/pole. The magnetic properties of nickel apply a magnetic force on the core which induces, or pushes, the magnetic core to a "desirable" demagnetized state.
  • Figure 1 shows a plan view of thin film head 12 comprising core 13, including upper core piece 14 and lower core piece 16. Coils turns -4-
  • Upper core piece 14 includes upper core tip 20, while lower core piece 16 includes lower pole tip 22 (yokes are not shown in this view).
  • Gap 24 is formed between upper pole tip 20 and lower pole tip 22.
  • alumina A1 2 0 3 ) fills the gap.
  • a magnetic storage medium (not shown) may be placed near gap 24 such that information may be written on or read from the medium.
  • FIG. 1 Also shown in Figure 1 is an arrow labeled H (Applied) indicating the direction of the applied magnetic field H, and an arrow labeled M (Relaxed) indicating the magnetization vector M of the thin film head 12 in its relaxed state.
  • a magnetic storage medium such as a magnetic disc, moves in the region near gap 24 formed between upper pole tip 20 and lower poler tip 22.
  • magnetic field H is applied to thin film head 12 in the direction shown by the arrow labeled H (Applied).
  • This applied magnetic field causes magnetization vector M of the pole material to change direction from its easy axis direction, indicated by the arrow labeled M (Relaxed), to the direction indicated by the arrow formed by the dashed line labeled M (Resultant).
  • vector M (Resultant) is deflected away from the easy axis in the direction toward gap 24 and magnetic field H (Applied)
  • upper pole tip 20 will become an increasingly strong north pole while lower pole tip 22 becomes the south pole.
  • This causes a fringe field (not shown) to form around gap 24 with a magnetic field vector having a direction from upper pole tip 20 to lower tip 22.
  • the magnetic domain pattern of thin film head 12 When data is not being written onto a magnetic medium, it is desirable for the magnetic domain pattern of thin film head 12 to be in an easy axis orientation, except for the edges. In other words, when there is no magnetic field H being applied to thin film head 12, the magnetization of thin film head 12 should be in its relaxed state, M (Relaxed). Often times, however, thin film heads exhibit an unstable magnetic domain pattern after the termination of a write process.
  • Figure 2 diagrammatically shows an unstable prior art thin film head 12P.
  • the direction of magnetization in the domains of upper core piece 14 were deflected away from the easy axis (not shown). After the current was terminated, upper core piece 14 did not return to a relaxed magnetic state.
  • Arrows 15 indicate the direction of magnetization vectors in the magnetic domains across upper core piece 14 after the termination of the write current.
  • Lines 17 indicate domain walls which exist after the termination of a write current.
  • Upper core piece 14, as shown in Figure 2 exhibits vertical domain wall 17A perpendicular to pole tip 20. The presence of domain wall 17A perpendicular to pole tip 20 can cause magnetic read instability. This instability causes head wiggle which significantly degrades readback performance.
  • FIG. 3 diagrammatically shows a magnetically stable thin film head made in accordance with the present invention.
  • Thin film head 12 is -6- shown including arrows 15 which indicate the direction of magnetization vectors M (Relaxed) in the magnetic domains across upper pole piece 14.
  • Lines 17 show domain walls.
  • Thin film head 12 is shown in its minimum energy relaxed state after removal of the write current.
  • the orientation of the various magnetic domains shown in Figure 3 is desirable because there are no vertical domain walls in or near pole tip 20.
  • the practical result of a magnetically stable core is less readback noise than that of prior art thin film head 12P shown in Figure 2.
  • FIG. 4 shows a cross-sectional view of thin film magnetic head 12 made in accordance with the present invention.
  • Thin film head 12 includes substrate 25 and core 13.
  • Core 13 comprises upper yoke 11, upper pole piece 14, lower yoke 10 and lower pole piece 16.
  • Upper pole piece 14 and lower pole piece 16 form upper pole tip 20 and lower pole tip 22, between which gap 24 is formed.
  • Core 13 also includes rear upper portion 26 and rear lower portion 28.
  • Thin film head 12 uses two levels of core windings formed by coils 18. Both levels of coils 18 are wound around center 30 of core 13, with a portion of the winding being sandwiched between core 13.
  • basecoat 36 is an insulator such as alumina, A1 2 0 3 .
  • the area between core 13 is filled with insulating material 38.
  • insulating material 38 is photoresist.
  • Gap 24 between upper pole tip 20 and lower pole tip 22 is filled with alumina, A1 2 0 3 .
  • Insulating material 38 is also sandwiched between rear upper and lower portions 26 and 28 of core 13.
  • Core 13 is separated from substrate 25 by basecoat 36 (shown in Figure 5).
  • the present invention employs a nickel seed layer 37 sandwiched between basecoat 36 and core 13. During fabrication, multiple heads similar to thin film head 12 may be deposited across an entire surface of substrate 25. For the purposes of this example, however, only the fabrication of single thin film magnetic head 12, is shown. -7-
  • FIG. 5 shows the fabrication process which begins with basecoat layer 36 being deposited across the entire surface of substrate 25 of a slider (not shown).
  • Base coat 36 comprises a non-conductive alumina material and is usually applied with sputtering techniques.
  • First nickel seed layer 37 is sandwiched between basecoat 36 and the bottom of magnetic core 13.
  • Layer 37 serves as a foundation for the bottom of magnetic core 13.
  • a thin film layer of magnetic material, such as permalloy, is applied across the surface of nickel seed layer 37. This thin film layer forms the bottom of magnetic core 13 including lower yoke 10, lower pole tip 22, lower rear portion 28 and part of center 30.
  • insulating layer 38 is deposited upon the bottom of core 13.
  • Alumina is deposited in gap 24.
  • coil turns 18 are deposited upon insulating layer 38 and are wound around center 30.
  • Insulating layer 38 is built up to cover coil turns 18.
  • Second nickel seed layer 39 is sandwiched between insulating layer 38 and the top magnetic core 13.
  • another layer of magnetic material such as permalloy is deposited over the second nickel seed layer to form the top of magnetic core 13 including upper yoke 11, upper pole piece 14, rear upper portion 26 and a portion of center 30. All layers are deposited using either electrodeposition or sputtering techniques.
  • Tests reveal that thin film magnetic heads made in accordance with the method of the present invention reduces to approximately one half the amount of head wiggle associated with read instability of prior art thin film heads.
  • the pure nickel seed layers 37 and 39 apply a magnetic force on each half of magnetic core 13 such that when in a relaxed state, the domain patterns of the core (i.e. yokes and poles) are pushed toward an easy axis orientation.
  • the method of the present invention is suitable for transducers made of any type of magnetic material. The method may also be used in conjunction with other forms of data storage medium.
  • the -8- present invention results in an efficient, cost effective means to increase the magnetic stability of a transducer.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Magnetic Heads (AREA)

Abstract

Tête magnétique à couche mince (12) et procédé de fabrication de ladite tête comprenant le dépôt d'une première couche germe en nickel (37) sur un substrat (25), la constitution d'une partie de base (16) de noyau magnétique (13) sur ladite première couche (37), le dépôt d'une deuxième couche en nickel (39) et la constitution d'une partie supérieure (14) de noyau magnétique (13) sur ladite deuxième couche (39). Ceci permet d'améliorer considérablement la stabilité de la tête à couche mince (12) lorsqu'elle est en état relâché, ainsi que ses performances de lecture.
PCT/US1993/011571 1993-11-23 1993-11-23 Tetes magnetiques a couche mince comportant des sous-couches minces en nickel WO1995014991A1 (fr)

Priority Applications (8)

Application Number Priority Date Filing Date Title
DE69318042T DE69318042T2 (de) 1993-11-23 1993-11-23 Dünnfilmmagnetköpfe mit dünnen nickelunterlagen
SG1996008482A SG46693A1 (en) 1993-11-23 1993-11-23 Thin film magnetic heads with thin nickel underlayers
EP94903341A EP0730774B1 (fr) 1993-11-23 1993-11-23 Tetes magnetiques a couche mince comportant des sous-couches minces en nickel
US08/190,090 US5666250A (en) 1993-11-23 1993-11-23 Thin film magnetic heads with thin nickel underlayers
JP51502795A JP3539732B2 (ja) 1993-11-23 1993-11-23 薄いニッケル下層を備えた薄膜磁気ヘッド
PCT/US1993/011571 WO1995014991A1 (fr) 1993-11-23 1993-11-23 Tetes magnetiques a couche mince comportant des sous-couches minces en nickel
US08/188,078 US6125010A (en) 1993-11-23 1994-01-27 Mo-Au gold seedlayer in thin film heads
HK98110570A HK1010069A1 (en) 1993-11-23 1998-09-10 Thin film magnetic heads with thin nickel underlayers

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SG1996008482A SG46693A1 (en) 1993-11-23 1993-11-23 Thin film magnetic heads with thin nickel underlayers
PCT/US1993/011571 WO1995014991A1 (fr) 1993-11-23 1993-11-23 Tetes magnetiques a couche mince comportant des sous-couches minces en nickel

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US08/188,078 Continuation-In-Part US6125010A (en) 1993-11-23 1994-01-27 Mo-Au gold seedlayer in thin film heads

Publications (1)

Publication Number Publication Date
WO1995014991A1 true WO1995014991A1 (fr) 1995-06-01

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PCT/US1993/011571 WO1995014991A1 (fr) 1993-11-23 1993-11-23 Tetes magnetiques a couche mince comportant des sous-couches minces en nickel

Country Status (1)

Country Link
WO (1) WO1995014991A1 (fr)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4103315A (en) * 1977-06-24 1978-07-25 International Business Machines Corporation Antiferromagnetic-ferromagnetic exchange bias films
DE2833249A1 (de) * 1978-07-28 1980-02-07 Siemens Ag Lamellierter duennschicht-magnetkopf und verfahren zu seiner herstellung
JPS5933613A (ja) * 1982-08-20 1984-02-23 Fujitsu Ltd 薄膜磁気ヘツドの磁極および製法
EP0114076A2 (fr) * 1983-01-17 1984-07-25 Hitachi, Ltd. Tête magnétique
WO1985002706A1 (fr) * 1983-12-13 1985-06-20 Karman Peter Tete magnetique integree, en particulier pour des unites de stockage de donnees
EP0301823A2 (fr) * 1987-07-29 1989-02-01 Digital Equipment Corporation Tête d'enregistrement magnétique à trois pôles
WO1989005505A1 (fr) * 1987-12-04 1989-06-15 Digital Equipment Corporation Poles stratifies pour tetes d'enregistrement
EP0332320A2 (fr) * 1988-03-09 1989-09-13 Quantum Corporation Procédé de fabrication de pôles d'enregistrement magnétique
EP0387143A2 (fr) * 1989-03-08 1990-09-12 Commissariat A L'energie Atomique Procédé de dépôt électrolytique sur un substrat semiconducteur

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4103315A (en) * 1977-06-24 1978-07-25 International Business Machines Corporation Antiferromagnetic-ferromagnetic exchange bias films
DE2833249A1 (de) * 1978-07-28 1980-02-07 Siemens Ag Lamellierter duennschicht-magnetkopf und verfahren zu seiner herstellung
JPS5933613A (ja) * 1982-08-20 1984-02-23 Fujitsu Ltd 薄膜磁気ヘツドの磁極および製法
EP0114076A2 (fr) * 1983-01-17 1984-07-25 Hitachi, Ltd. Tête magnétique
WO1985002706A1 (fr) * 1983-12-13 1985-06-20 Karman Peter Tete magnetique integree, en particulier pour des unites de stockage de donnees
EP0301823A2 (fr) * 1987-07-29 1989-02-01 Digital Equipment Corporation Tête d'enregistrement magnétique à trois pôles
WO1989005505A1 (fr) * 1987-12-04 1989-06-15 Digital Equipment Corporation Poles stratifies pour tetes d'enregistrement
EP0332320A2 (fr) * 1988-03-09 1989-09-13 Quantum Corporation Procédé de fabrication de pôles d'enregistrement magnétique
EP0387143A2 (fr) * 1989-03-08 1990-09-12 Commissariat A L'energie Atomique Procédé de dépôt électrolytique sur un substrat semiconducteur

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
"Laminated Seed Layers for Plated Thin Film Heads and Structures", IBM TECHNICAL DISCLOSURE BULLETIN, vol. 35, no. 1B, June 1992 (1992-06-01), ARMONK, N. Y., US, pages 457 - 459 *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 129 (P - 280)<1566> 15 June 1984 (1984-06-15) *
See also references of EP0730774A1 *
Y. NAGAI ET AL.: "Magnetic Anisotropy in Ni/Fe Artificial Lattice Film", JOURNAL OF APPLIED PHYSICS, vol. 64, no. 1, August 1988 (1988-08-01), WOODBURY, NY, US, pages 1343 - 1346, XP000020305 *

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