JP2002367125A - Magneto-resistive element and manufacturing method of magneto-resistive element, and thin film magnetic head device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the demagnetization or the erase of magnetization when the magnetic recording information is reproduced. SOLUTION: The thin film magnetic head is arranged so that a hard bias layer is retreated from the confronted surface of a recording medium in the height direction farther than a multi-layer film demonstrating the magneto- resistive effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element exhibiting a magnetoresistive effect, a method of manufacturing the same, and a thin-film magnetic head device using the same.

[0002]

2. Description of the Related Art FIG. 17 is a front view of a conventional magnetoresistive element viewed from a surface facing a recording medium, and FIG.
8 is a sectional view taken along line XVIII-XVIII in FIG. A hard bias layer 102 and an electrode layer 103 are formed on both sides of the multilayer film 101 having a track width and exhibiting a magnetoresistive effect in the track width direction (X direction). The moving direction of a recording medium such as a hard disk is the Z direction,
The direction of the leakage magnetic field from the recording medium is the Y direction.

For example, in the case of an AMR (anisotropic magnetoresistance) element, the multilayer film 101 is called an MR3 layer.
Soft magnetic layer (SAL layer), non-magnetic conductive layer (SHUNT layer)
Each layer of the magnetoresistive layer (MR layer) is laminated. When the direction of current and the direction of magnetization in the MR3 layer are parallel to each other, the resistance increases, and when the directions are perpendicular to each other, the resistance increases. It is configured to be low.

In such a magnetoresistive effect element,
When recording information is reproduced from each track portion of a recording medium, a phenomenon of demagnetizing or demagnetizing magnetic recording information recorded on an adjacent track portion has become a problem.

[0005] In particular, when a deposition (ME) tape having a low coercive force (Hc) is used as a recording medium, such a phenomenon is conspicuous. For example, AMR is used as a magnetoresistive element of a thin film magnetic head. When using an element,
It was found that the larger the product (MRt) of the magnetic flux density and the film thickness of the hard bias layer, the greater the demagnetization amount. On the other hand, the smaller the coercive force (Hc) of the recording medium,
There is also a tendency that demagnetization is easy.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a magnetoresistive element capable of effectively preventing troubles such as demagnetizing or demagnetizing information magnetically recorded on a recording medium, and a method of manufacturing the same. It is another object of the present invention to provide a thin-film magnetic head device using the same.

[0007]

SUMMARY OF THE INVENTION According to the present invention, as a result of pursuing the causes of the above-described demagnetization and demagnetization, in a conventional magnetoresistance effect element, permanent magnet films are provided on both sides of a multilayer film exhibiting a magnetoresistance effect on a recording medium facing surface. The present invention has been completed by finding that a certain hard bias film is exposed and that the hard bias film exposed on the recording medium facing surface is a cause of demagnetization and demagnetization. That is, the present invention includes a multilayer film having a track width and exhibiting a magnetoresistive effect, a hard bias layer provided on both sides of the multilayer film, and an electrode layer laminated on the hard bias layer. In the magnetoresistive element described above, the hard bias layer is recessed in the height direction from the surface facing the recording medium with respect to the multilayer film. It has been confirmed that when the hard bias layer is retracted from the surface facing the recording medium, demagnetization and demagnetization of the recording medium can be prevented. The recording medium facing surface is an ABS surface in a magneto-resistance effect element for a hard disk, and is a sliding surface of a recording medium in a magneto-resistance effect element for a tape.

It is preferable that a non-magnetic protective layer be provided on a portion of the hard bias layer receding from the surface facing the recording medium. This protective layer is preferably further insulating.

Further, according to the method of manufacturing a magnetoresistive effect element of the present invention, a multilayer film exhibiting a magnetoresistive effect is laminated on a substrate, and a multilayer film on both sides of the multilayer film is formed while leaving a region having a track width. A hard bias layer is laminated on both side areas where the hard bias layer has been removed, and a region having a certain depth is cut in a height direction from a surface where the hard bias layer is exposed as a recording medium facing surface, and the hard bias layer is removed. It is characterized in that an electrode layer is laminated on the layer.

[0010] In the hard bias layer, it is desirable that a non-magnetic protective film be laminated and filled in a fixed area facing the recording medium facing surface before the electrode layer is laminated.
This protective film is preferably further insulative.

Various types can be used for the multilayer film exhibiting the magnetoresistance effect. For example, a multilayer film including a soft magnetic layer (SAL layer), a nonmagnetic layer (SHUNT layer) and a magnetoresistive layer (MR layer) is arranged in order from the bottom, and an antiferromagnetic layer, a fixed magnetic layer, and a nonmagnetic layer are arranged in order from the bottom. It can be composed of a multilayer film composed of a conductive layer and a free magnetic layer, or a multilayer film composed of a free magnetic layer, a nonmagnetic conductive layer, a fixed magnetic layer, and an antiferromagnetic layer in order from the bottom. Multilayer films exhibiting these magnetoresistive effects are well known. These multilayer films
Preferably, it is formed on a seed layer.

More specifically, a structure in which a first fixed magnetic layer, a non-magnetic intermediate layer, and a second fixed magnetic layer are laminated in this order from the bottom can be used as the fixed magnetic layer. As the layers, a configuration in which a first free magnetic layer, a non-magnetic intermediate layer, and a second free magnetic layer are stacked in this order from the bottom can be used.

The magnetoresistive element may be a dual spin-valve thin film element.

Further, a thin-film magnetic head device of the present invention reproduces, or reproduces and records information recorded on a recording medium using the magnetoresistive element of the present invention. Holding force (Hc) is 120,000 (A /
m) It is characterized by the following.

In this thin film magnetic head device, an ABS element is used as the magnetoresistive element, and the product (MRt) of the magnetic flux density and the film thickness of the hard bias layer of the ABS element is 0.06 [T · μm] or less. It is preferred that

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an AMR (anisotropic magnetoresistive) element as a magnetoresistive element 1 of the present invention.
FIG. 2 is a cross-sectional view of a thin-film magnetic head using the resistive element 10 as viewed from the side facing the recording medium. FIG. 2 is a schematic cross-sectional view taken along the line III-III of FIG.

A shield layer is formed above and below the AMR element 10 in FIG. 1 (in the direction of laminating the thin films) via a gap layer (not shown).
The shield layer constitutes a thin-film magnetic head (MR head) for reproduction. If a recording inductive head is stacked on the MR head (Z direction), a recording / reproducing thin film magnetic head is obtained.

This thin film magnetic head is used as a reproducing head for a hard disk device (HDD) or a reproducing head for a helical scan type VTR, and detects recorded magnetic information recorded on a recording medium. In this embodiment, the coercivity (Hc) of the recording medium is 120,000 (A /
m) (that is, 1500 (Oe)) or less. In the figure, the X, Y, and Z directions are defined as a track width direction, a direction of a leakage magnetic field from a recording medium, and a moving direction of the recording medium.

In the AMR element 10 shown in FIGS. 1 and 2, a lower shield layer 13 is formed via a protective layer 12 on a substrate 11 made of a ceramic material such as alumina titanium carbide (AlTiC). The lower shield layer 13 is provided below the AMR element 10.
This is for performing a magnetic shield and is made of a magnetic material.

On the lower shield layer 13, a lower gap layer 14 is formed. The lower gap layer 14 is for ensuring electrical insulation, and generally uses alumina (Al ₂ O ₃ ).

The soft magnetic layer (SAL layer) 21, the nonmagnetic layer (SHUNT layer) 22, and the soft magnetic layer (SAL layer) 21
An MR3 layer 20 in which a magnetoresistive layer (MR layer) 23 is laminated is formed. The MR3 layer 20 has, for example, a thickness (thickness) in the stacking direction of about 0.05 μm and a dimension in the height direction of about 3 μm. On the other hand, this MR3 layer 2
The width dimension (Tw) of the upper surface 20a of the zero determines the magnetic track width (for example, about 8 μm). Note that a seed layer may be interposed on the formation surface α on which the MR3 layer 20 is to be stacked.

The soft magnetic layer (SAL layer) 21 is for applying a vertical bias to the MR element, and a NiFeNb alloy film is generally used. The soft magnetic layer 21
Is generally formed with a film thickness of 100 ° or more and 400 ° or less.

The nonmagnetic conductive layer (SHUNT layer) 22 is used to vertically bias the soft magnetic layer 21 with a magnetic field generated by a current in the nonmagnetic conductive layer 22.
Membranes are commonly used. This nonmagnetic conductive layer 22 is generally formed to a thickness of 50 ° to 100 °.

The magnetoresistive layer (MR layer) 23 is for sensing a leakage magnetic field from the medium, and generally uses a NiFe alloy film. This magnetoresistive layer 23 is generally formed to a thickness of 150 ° or more and 400 ° or less.

A hard bias layer 31 and an electrode layer 32 are laminated on both sides of the MR3 layer 20 in the track width Tw direction in order from the bottom. The hard bias layer 31 is recessed from the MR3 layer 20 by a certain depth (for example, 0.5 μm) in the height direction from the surface facing the recording medium, and a protection layer 33 is formed on the recess. Have been. That is, the MR3 layer 20 is provided on the surface facing the recording medium.
And the protective layer 33 are exposed, and the hard bias layer 31 is not exposed. The hard bias layer 31 is formed of a hard magnetic material such as a CoPt alloy or a CoPtCr alloy, and the protective layer 33 is formed of a non-magnetic and insulating material, for example, alumina (Al ₂ O ₃ ).

An electrode layer 32 is formed on the hard bias layer 31 and the protective layer 33. The electrode layer 32 is made of, for example, Au, Ta, Cr, Rh, W, and the like. On this electrode layer 32, a protective layer made of Ta is formed.

For example, the same alumina (A) as the lower gap layer 14 is formed on the MR3 layer 20 within the track width and the electrode layer 32 in the both side regions 2A formed in this manner.
The upper gap layer is formed using an electrically insulating material such as l ₂ O ₃ ), and an upper shield layer is formed on the upper gap layer using a magnetic material.

In the AMR element 10 configured as described above, the hard bias layer 31 is magnetized in the X direction in the figure, and the hard bias layer 31 applies a bias magnetic field to the magnetoresistive layer 23 in the X direction. Further, a bias magnetic field in the illustrated Y direction is applied from the soft magnetic layer 21 to the magnetoresistive layer 23. As a result, a magnetic field is applied to the magnetoresistive layer 23 in two directions, the X direction and the Y direction, so that a change in magnetization with respect to a change in the magnetic field of the magnetoresistive layer 23 is set to have a linear state. Here, the traveling direction of the recording medium is the Z direction, and when a leakage magnetic field from the recording medium is applied in the Y direction, the magnetization direction of the magnetoresistive layer 23 changes, so that the resistance value changes. Is detected as

According to the thin-film magnetic head of this embodiment, the hard bias layer 31 is retracted in the height direction from the surface facing the recording medium relative to the multilayer film 2, so that demagnetization and demagnetization of the recording medium can be prevented. . Further, a nonmagnetic protective layer 3 is provided on the recording medium facing surface side of the hard bias layer 31.
The presence of 3 makes it possible to flatten the surface facing the recording medium, prevent entry of fine dust, and ensure smooth sliding of the magnetic tape. If the protective layer is made of a soft magnetic material, the soft magnetic material is magnetized by the hard bias layer 31 and demagnetizes the recording medium. In addition, this protective layer 3
3 is made of an insulating material such as the alumina of the embodiment, whereby the wear resistance can be improved.

Next, a method of manufacturing the AMR element 10 of this embodiment will be described. (1) First, as shown in FIG. 3, a protective layer 12 made of an insulating material such as alumina and a lower shield layer 1 made of a magnetic material such as Permalloy and Sendust are formed on a substrate 11.
3, and a lower gap layer 14 made of an insulating material such as alumina is formed (first step).

(2) Next, each layer of the multilayer film 2 constituting the AMR element 10 is formed on the entire surface of the lower gap layer 14 (second step). That is, on the lower gap layer 14,
Soft magnetic layer (SAL layer) 2 made of NiFeNb alloy film
1, a nonmagnetic layer (SHUNT layer) 22 made of Ta or the like;
Layer (MR layer) 23 made of NiFe alloy or the like
Are sequentially laminated. On this magnetoresistive layer (MR layer) 23, a protective layer made of Ta or the like is formed.

The multilayer film 2 is formed by the MR of the AMR element 10 described above.
In addition to the three layers 20, for example, in the case of a bottom-type spin-valve thin film element, a multilayer film including an antiferromagnetic layer, a fixed magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer may be used in this order from the bottom. it can. In the case of a top-type spin-valve thin film element, a multilayer film in which a free magnetic layer, a nonmagnetic conductive layer, a fixed magnetic layer, and an antiferromagnetic layer are stacked in this order from the bottom can be used.

Further, in order to form a dual spin-valve type thin film element, an antiferromagnetic layer, a fixed magnetic layer, a nonmagnetic conductive layer, a free magnetic layer, a nonmagnetic conductive layer, a fixed It is a multilayer film in which a magnetic layer and an antiferromagnetic layer are sequentially stacked. In these multilayer films, the pinned magnetic layer includes a first pinned magnetic layer, a non-magnetic intermediate layer,
A synthetic ferri-pinned structure having a three-layer structure in which a second pinned magnetic layer is stacked may be used. The free magnetic layer may include a first free magnetic layer, a non-magnetic intermediate layer, and a second free magnetic layer in this order from the bottom. A synthetic ferri-free structure having a three-layer structure may be used.

(3) Next, as shown in FIG.
A resist layer R1 is formed in a central portion on the (MR3 layer 20) by a coating process and an exposure and development process (third step).

(4) Next, as shown in FIG. 5, the multilayer film 2 not covered with the resist layer R1 (MR3 layer 2
0) Both side regions 2A in the track width direction (X direction in the figure) are removed by etching (fourth step). The depth of both side regions 2A dug out by this etching is:
Lower gap layer 1 deeper than multilayer film 2 (MR3 layer 20)
The depth reaches 4. Thereby, the remaining multilayer film 2
Both end surfaces 20a of the (MR3 layer 20) are continuous inclined surfaces up to the upper surface, and the multilayer film 2 (MR3 layer 20) has a substantially trapezoidal shape.

(5) Then, as shown in FIG. 6, with the resist layer R1 laminated, a CoPt alloy or C
A hard magnetic material such as an oPtCr alloy is formed (fifth step). By this film formation, the hard magnetic material laminated on the resist layer R1 is thereafter removed together with the resist layer R1 by lift-off.

(6) Next, M in the direction perpendicular to the plane of FIG.
In order to set the R height, as shown in FIG. 7, in the track width direction (X), the
The resist layer R2 is formed on all of the hard bias layers 31 formed on both side areas 2A.
Are laminated (sixth step). The MR height is set by the length of the resist layer R2 in the direction perpendicular to the paper surface.

(7) Then, the portion of the multilayer film 2 other than the region covered by the resist film R2 is scraped off by ion milling or the like, and then, as shown in FIG. 8, the remaining resist layer R2 is removed (FIG. 8). 7th step).

(8) Next, in the steps shown in FIGS. 9 and 10, a region 31 '(see FIG. 10) of the hard bias layer 31, particularly including a surface exposed as a recording medium facing surface, is fixed in the height direction. In order to remove the depth H ′, a resist layer R3 is formed in a predetermined pattern (eighth step). As shown in FIG. 10, the resist layer R3 is formed without forming the resist layer R3 immediately above the hard bias layer 31 in both side regions 2A. The depth (width H ′) of the resist layer R3 is sufficiently larger than the depth H (for example, 0.5 μm) in the height direction for shaving the hard bias layer 31 shown in FIG. In other words, the resist layer R3 is formed over the entire surface of the substrate except for the rectangular hard bias layer removal region (hole) D in FIG.

(9) Next, in the steps shown in FIGS. 11 and 12, the hard bias layer 31 in the hard bias layer removal region D where the resist layer R3 is not formed is completely removed by ion milling or the like. To the desired depth) (ninth step).

(10) Then, as shown in FIG. 13, in a state where the resist layer R3 remains, the non-magnetic and insulating layer serving as the protective layer 33 is formed in the hard bias layer removal region D which has been dug out in the ninth step. , For example, alumina (Al ₂ O ₃ ) is formed by sputtering (tenth step). The alumina (Al ₂ O ₃ ) or the like to be formed is formed to have substantially the same thickness as the hard bias layer 31. At the time of this sputtering film formation, alumina (Al ₂ O ₃ ) or the like to be used is similarly laminated on the resist layer R3. Thereafter, the laminated resist layer R3 such as alumina is entirely removed by lift-off. In addition, instead of the nonmagnetic and insulating protective layer 33,
The electrode layer 32 made of a non-magnetic material may be formed in the hard bias layer removal region. Electrode layer 3 made of non-magnetic material
2 is not likely to be magnetized by the hard bias layer 31. However, in consideration of abrasion resistance, it is preferable that the protective layer 33 be insulative.

(11) Next, as shown in FIG. 14, over the entire region except the region where the protective layer 33 and the hard bias layer 31 formed in the hard bias layer removed region D are formed, A resist layer R4 is laminated. Then, from above, Au, Ta (tantalum), Cr, Rh,
The electrode layer 32 is formed by sputtering from a conductive material such as W (eleventh step).

(12) After the formation of the electrode layer 32 in this manner, the resist layer R4 is entirely removed, and then the MR layer is removed.
When an upper gap layer and an upper shield layer (not shown) are formed on the three layers 20 and the electrode layer 32, the AMR element 10 as shown in FIG. 15 is formed (twelfth step). Thereafter, when the AMR element 10 is cut at the recording medium facing surface including the hard bias layer removal region D, as shown in FIG. 1, the protective layer 33 is exposed on the recording medium facing surface, and the hard bias layer 31 A thin-film magnetic head that is recessed from the medium facing surface is obtained.

[0044]

EXAMPLE Next, as a recording medium, a High Hc tape and a Low Hc tape were used.
When an Hc tape is used, the magnetoresistive element of the present invention (a configuration in which the hard bias film is retreated in the height direction without exposing the hard bias film) and a comparative product (the hard bias film is retreated in the height direction from the ABS surface) And the structure exposed without being subjected to the above method).
A comparative experiment was conducted to examine the correlation between (T · μm) and the demagnetization amount [T · μm].

FIG. 16 shows the result. In FIG. 16, solid lines A and C show the relationship between the demagnetization amount and MR · t on the High Hc tape and the Low Hc tape using the magnetoresistive effect element of the present invention, respectively. D shows the relationship between the demagnetization amount and MR · t on the High Hc tape and the Low Hc tape using the comparative magnetoresistive element.

As can be seen from the experimental results, the high Hc
For both the tape and the Low Hc tape, it was confirmed that the magnetoresistive element of the present invention had a smaller amount of demagnetization and had better characteristics as a magnetoresistive element.

[0047]

According to the present invention, since the hard bias film is retreated in the height direction from the surface facing the recording medium without being exposed, the magnetic influence on the recording medium is greatly reduced. For example, it is possible to prevent information recorded on an adjacent track from being demagnetized or demagnetized, thereby improving reliability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an AMR element according to the present invention when viewed from a recording medium facing surface side.

FIG. 2 is a sectional view taken along line III-III in FIG.

FIG. 3 is a process chart showing a first step of the method for manufacturing the AMR element according to FIG. 1;

FIG. 4 is a process chart showing second and third steps of the method for manufacturing the AMR element.

FIG. 5 is a process chart showing a fourth step of the method for manufacturing the AMR element.

FIG. 6 is a process chart showing a fifth step of the method for manufacturing the AMR element.

FIG. 7 is a process chart showing a sixth step of the method for manufacturing the AMR element.

FIG. 8 is a process chart showing a seventh step of the method for manufacturing the AMR element.

FIG. 9 is a process chart showing an eighth step of the method for manufacturing the AMR element.

FIG. 10 is a sectional view taken along line XX in FIG. 9;

FIG. 11 is a process chart showing a ninth step of the method for manufacturing the AMR element.

FIG. 12 is a sectional view taken along line XII-XII in FIG.

FIG. 13 is a process chart showing a tenth step of the method for manufacturing the AMR element.

FIG. 14 is a process chart showing an eleventh step of the method for manufacturing the AMR element.

FIG. 15 is a cross-sectional view of the AMR element manufactured by the manufacturing method of the present invention as viewed from the side facing the recording medium.

FIG. 16 is a graph showing a comparative experiment between the present invention and a comparative example.

FIG. 17 is a cross-sectional view of a conventional AMR element viewed from a recording medium facing surface side.

18 is a sectional view taken along line XVIII-XVIII in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetoresistive element 10 AMR element 11 Substrate 13 Lower shield layer 14 Lower gap layer 2 Multilayer film 2A Both side area 20 MR3 layer 21 Soft magnetic layer (SAL layer) 22 Nonmagnetic layer (SHUNT layer) 23 Magnetoresistance layer (MR layer) 31) Hard bias layer 32 Electrode layer 33 Protective layer D Hard bias layer removed area R1 R2 R3 R4 Resist layer α Forming surface X Track width direction Y Height direction Z Stacking direction

Claims (7)

[Claims] 1. A magnetoresistive element comprising a multilayer film exhibiting a magnetoresistive effect, hard bias layers provided on both sides of the multilayer film, and an electrode layer laminated on the hard bias layer. Wherein the hard bias layer is retreated in the height direction from the surface facing the recording medium with respect to the multilayer film. 2. The magnetoresistive element according to claim 1, wherein a nonmagnetic protective layer is provided on a portion of the hard bias layer receded from the surface facing the recording medium. 3. The magnetoresistive element according to claim 2, wherein said protective layer is insulative. 4. A multilayer film exhibiting a magnetoresistive effect is laminated on a substrate, a multilayer film on both sides of the multilayer film is removed except for a region having a track width, and hard bias layers are formed on both sides of the removed film. The magnetoresistive effect is characterized in that a region having a certain depth is cut in the height direction from a surface where the hard bias layer is exposed as a recording medium facing surface, and an electrode layer is laminated on the hard bias layer. Device manufacturing method. 5. The non-magnetic insulating protective film according to claim 4, wherein the non-magnetic insulating protective film is formed before the electrode layer is laminated on the fixed region of the hard bias layer facing the recording medium facing surface. For manufacturing a magnetoresistive element in which a plurality of layers are stacked and filled. 6. A thin film magnetic head device for reproducing, or reproducing and recording information recorded on a recording medium, using the magnetoresistive effect element according to claim 1. Medium holding power (Hc) of 120,000
(A / m) or less. 7. The thin-film magnetic head device according to claim 6, wherein an AMR element is used as the magnetoresistive element, and the product (MR · t) of the magnetic flux density and the thickness of the hard bias layer of the AMR element is 0.1. A thin film magnetic head device having a thickness of not more than 06 [T · μm].