JP2001076322A - Method of manufacturing magnetoresistive head and method of manufacturing composite magnetic head - Google Patents

Abstract

[PROBLEMS] To provide a magnetoresistive head manufacturing method for manufacturing a magnetoresistive head having small distortion of a reproduction waveform and improving the yield in manufacturing the magnetoresistive head. SOLUTION: An element forming step of forming a plurality of element sections 12 on a wafer 11, and a wiring forming step of forming wiring 13 for collectively supplying current to the plurality of element sections 12 formed in the element forming step. While performing a heat treatment on the wafer on which the wirings 13 are formed, a current is collectively applied to each of the plurality of element parts 13 through the wirings 13 formed in the wiring forming step, and Fixing the magnetization direction of the fixed-side magnetic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetoresistive head for producing a magnetoresistive head for detecting the strength of a magnetic field by utilizing a resistance change according to the strength of the magnetic field, and a method thereof. The present invention relates to a composite magnetic head manufacturing method for manufacturing a composite magnetic head in which a magnetoresistive head and a recording head that generates a magnetic field by a coil are combined.

[0002]

2. Description of the Related Art In recent years, with the spread of computers, a large amount of information has been handled on a daily basis. To record and reproduce such a large amount of information, a hard disk drive (HDD: Hard Disk Drive) has been used. )
Is used. The HDD generally includes a magnetic disk having a surface made of a magnetic material, and a composite magnetic head in which a recording head for recording information on the magnetic disk and a reproducing head for reproducing information recorded on the magnetic disk are combined. . The recording head has minute coils and is arranged close to the magnetic disk, and the magnetic field generated from the coils of the recording head magnetizes the surface of the magnetic disk for each minute area (one bit area). On a magnetic disk, information is recorded as the direction of magnetization in a 1-bit area. The reproduction head outputs an electric reproduction signal corresponding to a magnetic field generated from the magnetization of the one-bit area, and the information recorded on the magnetic disk is reproduced through the reproduction head.

At present, most reproducing heads mounted on HDDs include a magnetoresistive head (MR head) utilizing a magnetoresistive effect in which the resistance changes according to an external magnetic field.
Is used. However, as the recording density of the magnetic disk increases, the sensitivity of the MR head is particularly high, that is, a spin-valve magnetoresistive head (Spi) that produces a large output voltage change with a change in an external magnetic field.
n Valve Magnetoresistive
Head) is in full swing. Hereinafter, this spin valve magnetoresistive head is referred to as a spin valve GMR head.

The spin valve GMR head has a free magnetic layer, a nonmagnetic metal layer, a fixed magnetic layer having a fixed magnetization direction, and a fixed magnetic layer having a fixed magnetization direction. A spin valve film composed of a multilayer film including an antiferromagnetic layer for fixing the magnetization direction of the spin valve, a shield layer for magnetically shielding the spin valve film, and the like. This spin-valve film produces a resistance change according to a relative angle change between the magnetization direction of the fixed-side magnetic layer and the magnetization direction of the free-side magnetic layer.
The high sensitivity of the R head is derived from the large change in resistance.

[0005] The spin valve film electrode terminals are arranged, in operation of the spin valve GMR head, the sense current I _s is flown to the spin valve film from the electrode terminals.
With the current flowing in this manner, the spin valve GM
When the R head is moved relatively close to the magnetic disk, the electric resistance value of the spin valve film sequentially changes in accordance with the signal magnetic field H _sig from the magnetic disk, and this electric resistance value and the sense current value I An output voltage having a value represented by a product of _s and _s is output.

[0006] Here, the resistance value of the spin valve film is magnetic.
Signal magnetic field H from disk_sigChanges linearly with changes in
Is preferred. To achieve such a linear change
The signal magnetic field H_sigThere is no fixed side
The magnetization direction of the magnetic layer and the magnetization direction of the free side magnetic layer
Ideally, it forms an angle of 90 °. This angle is 9
In the state deviated from 0 °, the spin valve GMR head
The output voltage is the signal magnetic field H _sigLinear response to the input
Failures such as distortion of the output voltage reproduction waveform
You.

Conventionally, this angle adjustment is performed, for example, when a spin valve GMR head is formed on a wafer, after the spin valve film is formed on the wafer, the magnetization of the fixed magnetic layer is fixed in a predetermined direction. Then, a pin annealing process of heating while applying a magnetic field is performed so that the direction of the easy axis of the free side magnetic layer or the shield layer is fixed to the fixed side magnetic layer with respect to the spin valve film subjected to the pin annealing process. This is performed by performing a free return process in which heating is performed while applying a magnetic field so as to direct the light in a predetermined direction that forms an angle of 90 ° with the direction in which the magnetization of the layer is fixed. However, due to the effect of the free return processing, the direction of magnetization of the fixed-side magnetic layer fixed by the pin annealing processing is easily inclined, that is, the angle is easily shifted from 90 °. By adjusting the processing conditions of these two processes, the inclination of the magnetization of the fixed magnetic layer in the free return process can be suppressed to a small value. However, in addition to these two processes, heat treatment is often required for manufacturing a spin valve GMR head. Even if this heat treatment is performed in the absence of a magnetic field, the magnetization of the fixed magnetic layer is In addition, it tends to tilt due to the demagnetizing field of the fixed magnetic layer itself.

A method of manufacturing such a spin valve GMR head for suppressing the inclination of the magnetization of the fixed magnetic layer is disclosed in
0-334415. This manufacturing method
When forming a plurality of spin-valve GMR heads on a wafer, a current is applied to the spin-valve film formed on the wafer at a time to raise the temperature near the fixed-side magnetic layer and generate a magnetic field generated by the current. by, which fixes the magnetization of the fixed magnetic layer without affecting the direction of the easy axis of magnetization of the free magnetic layer and the shield layer, as a current flowing through the spin valve film, 3 times or more of the sense current I _s A pulse current having a current value of is recommended.

[0009]

However, the sense current I
_When a current having a magnitude of at least three times _s flows, ions constituting each layer of the spin valve film move due to an electrophoresis phenomenon, and the thickness of each layer becomes non-uniform. Of sensitivity and spin valve G
The MR head is likely to be destroyed, which may deteriorate the yield in manufacturing the spin valve GMR head.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a method of manufacturing a magnetoresistive head for producing a magnetoresistive head having a small distortion of a reproduced waveform and improving the yield in the production of the magnetoresistive head, and a reproduced waveform. It is an object of the present invention to provide a composite magnetic head manufacturing method for manufacturing a composite magnetic head having a small distortion and improving the yield in manufacturing the composite magnetic head.

[0011]

In order to achieve the above object, a method of manufacturing a magnetoresistive head according to the present invention comprises a free magnetic layer whose magnetization direction changes in response to an external magnetic field and a fixed magnetic layer having a fixed magnetization direction. A magnetoresistive element, which is a multilayer film including a side magnetic layer and exhibits a resistance change in accordance with the strength of an external magnetic field, and a sense current is passed through the magnetoresistive element to change the voltage according to the resistance change A method for manufacturing a magnetoresistive head for producing a magnetoresistive head that outputs a plurality of magnetoresistive elements, wherein an element forming step of forming a plurality of magnetoresistive elements on a wafer, and a plurality of magnets formed in the element forming step. A wiring forming step of forming a wiring for supplying a current to the resistive effect element at a time; and heating the plurality of magnetoresistive effect elements while forming the plurality of magnetic fields through the wiring formed in the wiring forming step. Electric current collectively each anti effect element, and having a first magnetization direction fixing step of fixing the direction of magnetization of the magneto-resistive element each of the fixed magnetic layer.

As described above, by applying a current to the magnetoresistive element while performing a heat treatment on the magnetoresistive element,
The free side magnetic layer and one of the layers constituting the magnetoresistive head, such as a shield layer for magnetically shielding the magnetoresistive element, have almost no influence on the direction of the axis of easy magnetization. The magnetization of the magnetic layer is fixed in a predetermined direction. By adjusting the direction of magnetization of the fixed-side magnetic layer and the direction of the axis of easy magnetization of the free-side magnetic layer and the shield layer to be orthogonal to each other, the magnetoresistive head manufactured by this method of manufacturing a magnetoresistive head is manufactured. The reproduction waveform of the effect type head has a small distortion.

Further, in the case of performing the heat treatment as described above, there is no need for heating by a current, and the current value of the current flowing through the magnetoresistive element can be suppressed low. In this case, the magnetoresistive element is hardly destroyed, and the yield in manufacturing the magnetoresistive head is improved.

In the method of manufacturing a magnetoresistive head according to the present invention, in the first magnetization direction fixing step, the current value of the current flowing through each of the magnetoresistive elements is the current value of the sense current or It is preferable that the current value is smaller than the current value of the sense current.

As described above, the current value of the sense current that is safely passed through the magnetoresistive element when the magnetoresistive head is actually used depends on the magnetoresistive effect during the heat treatment in the method of manufacturing the magnetoresistive head. It is a measure of the current value of the current flowing through the element.

In the method of manufacturing a magnetoresistive head according to the present invention, when a current is applied to each of the plurality of magnetoresistive elements collectively in the first magnetization direction fixing step, the magnetoresistive effect is reduced. It is preferable to apply an external magnetic field to a region including the element in a direction corresponding to the axis of easy magnetization of the free magnetic layer.

As described above, since the external magnetic field is applied to the region including the magnetoresistive effect element in the direction corresponding to the easy axis of the free magnetic layer, the method of manufacturing the magnetoresistive head can be applied to the free magnetic layer. The direction of magnetization of the fixed-side magnetic layer can be fixed while controlling the direction of the easy axis of magnetization of the magnetic layer and the shield layer more reliably.

In the method of manufacturing a magnetoresistive head according to the present invention, after forming a plurality of magnetoresistive elements on a wafer in the element forming step, the method may be performed before executing the first magnetization direction fixing step. And applying an external magnetic field in a predetermined direction while heating the plurality of magnetoresistive elements to control the direction of the easy axis of the free side magnetic layer of the magnetoresistive element. It may be something.

In the method of manufacturing a magnetoresistive head according to the present invention, the plurality of magnetoresistive elements formed in the element forming step may be heated in a predetermined direction before the easy axis control step. And a second magnetization direction fixing step of fixing the magnetization direction of the fixed side magnetic layer of the magnetoresistive element by applying the external magnetic field of the above.

In order to achieve the above object, a method of manufacturing a composite magnetic head according to the present invention is a multilayer film including a free magnetic layer whose magnetization direction changes in response to an external magnetic field and a fixed magnetic layer whose magnetization direction is fixed. A magnetoresistive effect element that has a magnetoresistive effect element exhibiting a resistance change according to the strength of an external magnetic field, and outputs a voltage that varies according to the resistance change when a sense current flows through the magnetoresistive effect element. And a recording head having a recording coil and generating a magnetic field from the recording coil. A method of manufacturing a composite magnetic head, comprising: forming a plurality of magnetoresistive elements on a wafer. An element forming step, a wiring forming step of forming a wiring for supplying current to the plurality of magnetoresistive elements formed in the element forming step collectively, and a recording coil of the recording head, A coil forming step of forming the recording coil while surrounding the recording coil with a machine insulating material; and forming the organic insulating material surrounding the recording coil formed in the coil forming step by a heat treatment in the wiring forming step. And a magnetization direction fixing step of flowing a current to each of the plurality of magnetoresistive elements through the interconnects collectively and fixing the direction of magnetization of the fixed-side magnetic layer of each of the magnetoresistive elements. .

In the same manner as in the above-described method of manufacturing the magnetoresistive head according to the present invention, the method of manufacturing the composite type magnetic head almost affects the direction of the easy axis of magnetization of the free side magnetic layer and the shield layer. The magnetization of the fixed-side magnetic layer is fixed in a predetermined direction without any problem, and the distortion of the reproduction waveform of the composite magnetic head manufactured by this composite magnetic head manufacturing method is small. In addition, in this composite magnetic head manufacturing method, the magnetoresistive effect element is hardly destroyed, and the yield in manufacturing the composite magnetic head is improved.

In this composite magnetic head manufacturing method as well, in the same manner as in the above-described magnetoresistive head manufacturing method of the present invention, in the above-described magnetization direction fixing step of the composite magnetic head manufacturing method, the magnetic flux is applied to each of the magnetoresistive elements. The current value of the current to be applied is preferably the current value of the sense current or a current value smaller than the current value of the sense current, and in the above-described magnetization direction fixing step of the composite magnetic head manufacturing method. When a current is applied collectively to each of the plurality of magnetoresistive elements, an external magnetic field may be applied to a region including the magnetoresistive elements in a direction corresponding to the axis of easy magnetization of the free magnetic layer. preferable.

Also, the method for manufacturing a composite magnetic head is as follows.
The method may include a step corresponding to the easy axis control step and the second magnetization direction fixing step in the method of manufacturing a magnetoresistive head. If the composite magnetic head manufacturing method includes these steps and the magnetization direction of the fixed magnetic layer is fixed in advance by these steps, the organic insulating material may be temporarily cured by a simple heat treatment. The direction of the magnetization of the fixed-side magnetic layer is tilted by its own demagnetizing field, but by flowing a current through the magnetoresistive effect element as in the above-described magnetization direction fixing step of the composite magnetic head manufacturing method, The direction of the magnetization is maintained.

[0024]

Embodiments of the present invention will be described below.

The present invention relates to a method of manufacturing a magnetoresistive head and a method of manufacturing a composite magnetic head. First, a spin valve GMR head and a spin valve GMR head manufactured by a method of manufacturing a magnetic head according to the present embodiment to be described later. The composite magnetic head will be described, and then embodiments of the spin valve GMR head and the method of manufacturing the composite magnetic head will be described.

[Spin Valve GMR Head] FIG. 1 is a perspective view showing a main part of a spin valve GMR head manufactured by the magnetic head manufacturing method of the present embodiment, and FIG.
FIG. 2 is a side sectional view of the spin valve GMR head shown in FIG.

As shown in these figures, the spin-valve GMR head 10 has an underlayer 1 and a first magnetism formed on the underlayer 1 showing soft magnetism in which the direction of magnetization rotates in response to an external magnetic field. A free magnetic layer 2a, a second free magnetic layer 2b formed on the first free magnetic layer 2a and having the same soft magnetism as the first free magnetic layer 2a, and a second free magnetic layer 2b. A nonmagnetic metal layer 3 formed on the side magnetic layer 2b; a fixed magnetic layer 4 formed on the nonmagnetic metal layer 3 and magnetized in a predetermined fixed direction; Formed on the fixed side magnetic layer 4 by exchange coupling with the fixed side magnetic layer 4.
And a capping layer 6 formed on the antiferromagnetic layer 5 to fix the direction of magnetization. This spin valve film corresponds to the magnetoresistive element according to the present invention. Note that a layer made of a hard magnetic material may be used instead of the antiferromagnetic layer 5 in order to fix the magnetization direction of the fixed magnetic layer 4.

Further, the spin valve GMR head 10
As shown in FIG. 2, a pair of left and right electrode terminals 7a and 7b are formed on the cap layer 6 so as to cover both ends of the cap layer.
Are formed respectively. A pair of hard magnetic layers (not shown) is formed so as to be in contact with both ends of the first free magnetic layer 2a and the second free magnetic layer. These hard magnetic layers fix the magnetic domain walls of the free side magnetic layer and suppress the occurrence of Barkhausen noise, which is likely to occur in the read signal of the head. This spin valve G
In the MR head 10, a region between the pair of electrode terminals 7a and 7b is a signal detection region S for detecting a signal magnetic field from the magnetic disk. In the following, in order to specify the magnetization direction and the like of the spin valve GMR head 10, as shown in FIGS. 1 and 2, the thickness direction of the spin valve film, that is, the laminating direction of each of the above layers is assumed to be the z direction. The direction connecting the pair of electrode terminals 7a and 7b to each other is defined as the y direction, and the direction orthogonal to the yz plane is defined as the x direction. The spin valve GMR head 10 is used close to a magnetic disk, and when so close, the z direction corresponds to the direction in which the tracks of the magnetic disk extend, and the y direction corresponds to the direction of the track width. And the x direction corresponds to a direction perpendicular to the surface of the magnetic disk.

Next, the respective layers constituting the spin valve GMR head 10 will be described.

The underlayer 1 is, for example, a tantalum (Ta) film having a thickness of 50 Å (Å).

The first free magnetic layer 2a is made of, for example, a nickel-iron (NiFe) film having a thickness of about 40 °, and the second free magnetic layer 2b is made of, for example, a cobalt-iron film having a thickness of about 25 °.
It is composed of an iron-boron (CoFeB) film, and both layers together form the free magnetic layer 2.

The non-magnetic metal layer 3 is made of copper (C
u) consists of a film.

The free magnetic layer 2 has the above-described two-layer structure because the free magnetic layer 2 is formed on the first free magnetic layer 2a made of a NiFe film without the second magnetic layer 2b made of a CoFeB film. When the nonmagnetic metal layer 3 made of a Cu film is laminated, Ni and Cu are easily diffused between the two layers, and a second free side made of a CoFeB film that does not form a solid solution with Cu between the two layers. This is because such interdiffusion is prevented by incorporating the magnetic layer 2b. Also, the holding force H _c
Is not enough to serve as a free magnetic layer that changes the direction of magnetization in accordance with an external magnetic field.
And by a second free side first free magnetic layer 2a and a certain thickness is provided two-layer structure in which the base of the magnetic layer 2b made of small NiFe film retentive H _c made of CoFeB film, free side The rotation of the magnetization of the entire magnetic layer 2 is facilitated so that the free side magnetic layer plays an essential role.

The fixed side magnetic layer 4 is made of, for example,
It is made of an oFeB film.

The antiferromagnetic layer 5 has a large exchange coupling magnetic field,
It is preferable to use a material having a high blocking temperature at which the exchange coupling magnetic field becomes zero and having high corrosion resistance. The antiferromagnetic layer 5 is made of, for example, a film of an ordered alloy having a thickness of 100 ° or more, typically 150 °. Palladium-platinum-manganese (PdPtM)
n) membrane, platinum-manganese (PtMn) membrane, palladium-
Manganese (PdMn) film, nickel-manganese (NiM)
n) film and chromium-manganese (CrMn) film. These films have high corrosion resistance because they use platinum-based metals such as Pd and Pt. Further, since these films use an ordered alloy, the exchange coupling magnetic field is large and the blocking temperature is high. In the present embodiment, the antiferromagnetic layer 5 is typically made of PdPtMn. This PdP
The blocking temperature for tMn is 320 ° C.

The cap layer 6 is made of, for example, T
a film.

The pair of electrode terminals 7a and 7b are made of a conductive material, for example, titanium (T
i) a film, a gold (Au) film having a thickness of 800 ° formed on the Ti film, and a film having a thickness of 20 formed on the Au film.
It is formed of a film having a three-layer structure of a 0 ° Ti film.

[0038] described above, a pair of hard magnetic layer in contact with the respective opposite ends of the free magnetic layer 2 is made of, for example, large CoCrPt film holding force H _c.

Spin valve GM having such layers
The center of the functional surface of the R head 10 is in the spin valve film.
This spin-valve film exhibits a large change in resistance under a weak magnetic field, and has a relatively simple layer configuration, so that it is suitable for mass production.

The principle of operation of the spin valve GMR head 10 will be briefly described below with reference to FIG.

As described above, the spin valve GMR head 10 has the spin valve film. In this spin valve film, the antiferromagnetic layer 5 is exchanged with the fixed magnetic layer 4 in contact with the antiferromagnetic layer 5. The fixed side magnetic layer 4
The magnetization M _p by the exchange interaction, which is fixed toward the x direction as described above. On the other hand, in the free side magnetic layer 2, the direction of the magnetic anisotropy, that is, the direction of the easy axis of magnetization is oriented in the y direction, and the magnetization M of the free side magnetic layer 2
_f points in this y-direction when no external magnetic field is present. When a weak external signal magnetic field _Hsig is applied to the free side magnetic layer 2, the magnetization _Mf rotates according to the signal magnetic field _Hsig . The y direction is the same as the direction of the magnetic field applied to the free magnetic layer 2 by the hard magnetic layer in contact with the free magnetic layer 2 described above.

The electric resistance of the spin valve film, a free magnetic layer 2, depends on the angle θ formed by the signal magnetic field H _sig fixed magnetization M _p of the fixed magnetic layer 4 and rotated magnetization M _f according to And change. That is, the resistance value R between the two electrode terminals 7a and 7b changes in proportion to the cosine cos θ of the angle θ between the magnetization directions of the two layers as follows.

R = R_min+ (R_w/ 2) × (1-cos θ) where R_minIs the magnetization M_pAnd magnetization M_fFaces the same direction θ =
The resistance value at 0 °_wChanges according to the external magnetic field
Represents the maximum change width of the resistance value R. The resistance value R is
Magnetization M of both layers_pDirection and magnetization M_fIs opposite to the direction of
When the angle θ is 180 °, the angle becomes maximum. spin
In the valve GMR head 10, the signal magnetic field H _sigIs zero
In this case, the angle θ is 90 °.

Operation of this spin valve GMR head 10
Sometimes, a pair of electrode terminals 7a and 7b shown in FIG.
Sense current I_sIs shed. In this way
Current I_sIs flowing, the spin valve GM
With the R head 10 brought close to a magnetic disk (not shown)
When moved relatively, the magnetic field in the signal detection area S shown in FIG.
Magnetic field H from the optical disk, which is oriented in the x direction._sigReceiving
The signal magnetic field H_{s ig}Depending on the magnetization as described above
M_fThe electrical resistance of the spin valve film changes with the rotation of
And the sequentially changing electric resistance value and sense current value I_sWhen
An output voltage represented by the product of

[0045] If the signal magnetic field H _sig as described above and orthogonal to the magnetization M _p and the magnetization M _f at zero the angle θ forms a 90 °, relative to the signal magnetic field H _sig from the outside of the magnetic disk The resistance and output voltage of the spin valve film change linearly. The linear change in the resistance and the output voltage of the spin valve film as described above means that considering the angle θ ′ of θ ′ = θ−90 °, which is the deviation from the angle of 90 °, cos θ in the equation of the resistance value R described above. Where cos θ = cos (90 ° + θ ′) = sin
θ ′, which can be understood from the fact that when the deviation angle θ ′ is small, the resistance value R changes linearly with respect to the deviation angle θ ′.

When the signal magnetic field H _sig is zero, the angle θ
Deviates from 90 °, the output voltage of the spin valve GMR head 10 does not linearly respond to the input of the external signal magnetic field H _sig , and a failure such as a distortion in the reproduction waveform of the output voltage occurs. From the studies so far, it has been evaluated that the angle θ is preferably at least 80 ° in order for the spin valve GMR head 10 to withstand actual use.

[Composite Magnetic Head] FIG. 3 is a diagram showing the structure of a composite magnetic head when applied to a hard disk drive.

FIG. 5 shows a state in which the composite magnetic head 30 is positioned close to the magnetic disk 27 in the hard disk drive. In the figure, a composite magnetic head 30 is roughly divided into a reproducing head 31 and a recording head 32.
Numeral 0 has a piggy bag structure in which the recording head 32 is added to the back of the reproducing head 31. Spin valve GMR
The head 10 is used as a reproducing head 31 of the composite magnetic head 30.

As shown in the drawing, the reproducing head 31 uses a spin valve film 10 ', and the spin valve film and the electrode terminals 7a and 7b are sandwiched from both sides in the film thickness direction. Placed reproduction lower shield 2
1 and a reproduction upper shield 22.

The recording head 32 includes a recording coil 25 and an organic insulating layer 24 surrounding the recording coil 25.
And a recording gap film 23, and a recording lower magnetic pole (lower core) 22 and a recording upper magnetic pole 26 arranged on both sides of the recording gap film 23 and the organic insulating layer 24. In this case, the recording lower magnetic pole 22 is also used as the reproducing lower shield 22 described above.

FIG. 4 is a view of the reproducing head viewed from the magnetic disk side.

As shown in FIG.
1 and the reproducing upper shield 22, a gap insulating film 2
0 is provided, and the spin valve film 10 ′ is disposed in the window of the gap insulating film 20.

[Method of Manufacturing Magnetic Head] A method of manufacturing the composite magnetic head 30 shown in FIG. 3 will be described below with reference to a manufacturing process flowchart shown in FIG.

FIG. 5 is a flowchart showing the steps of manufacturing the composite magnetic head.

First, in step S40, the lower reproduction shield film 21 is formed on the wafer. As the wafer, for example, alumina titanium carbide (Al ₂ O ₃ TiC) wafer with a protective layer of Al ₂ O ₃ having a diameter of 4-5 inches and the like. The reproducing lower shield 21 is made of, for example, an FeN film. Through the steps described below, about 10,000 composite magnetic heads are collectively manufactured on this wafer.

In step S41, a lower reproducing gap film is formed on the lower reproducing shield 21. This reproducing lower gap film is made of an insulating material such as Al ₂ O ₃ .

In step S42, a spin valve film is formed on one surface of the wafer described with reference to FIG. More specifically, the underlayer 1, the free magnetic layer 2, the nonmagnetic metal layer 3, the fixed magnetic layer 4, the antiferromagnetic layer 5, and the cap layer 6 are arranged in this order.
Is formed by, for example, a sputtering method.

In step S43, the spin valve film formed in step S42 is heated while applying a magnetic field in the x direction, thereby changing the direction of magnetization of the fixed side magnetic layer 4 in the spin valve film to the application of this magnetic field. A pin annealing process for fixing in the x direction is performed. A typical processing condition in this pin annealing process is a magnetic field strength of 2500O.
e, heating temperature 280 ° C., heating time 3 hours. The direction of the magnetization of the fixed-side magnetic layer 4 is fixed by the pin annealing process because the above-described Pd in the spin valve film is fixed.
The antiferromagnetic layer 5 made of an ordered alloy such as PtMn does not show magnetism immediately after the spin valve film is formed, and becomes antiferromagnetic (ordered) only by performing a heat treatment in a magnetic field such as the above-described pin annealing. ) and in order to, the magnetization M _p of the fixed magnetic layer 4 by the antiferromagnetic reduction is fixed in the x direction is the direction of the magnetic field applied. Such ordering of an ordered alloy is based on a face-centered cubic lattice (fcc).
ntered cubic structure face-centered square lattice (fct: faced centered tet)
This is accompanied by a change in the crystal to a radial structure.

In step S44, the spin-valve film subjected to the pin annealing in step S43 is heated while applying a magnetic field in the y-direction, so that the free magnetic layer 4 in the spin-valve film and the reproducing lower shield 21 are heated. A free return annealing process is performed to direct the easy axis of magnetization in the y-direction and to enhance magnetic anisotropy. Typical processing conditions in the free-return annealing process include a magnetic field strength of 50 Oe,
The heating temperature is 230 ° C. and the heating time is 3 hours.

[0060] These Pin'aniru processing and free return annealing, but can be substantially perpendicular to the direction of the magnetization M _f direction and free magnetic layer 2 of the magnetization M _p of the fixed magnetic layer 4, the free return annealing Since the processing affects the magnetization M _p of the fixed magnetic layer 4, the direction of the magnetization M _p is inclined from the x direction toward the y direction. However, the magnitude of this inclination can be reduced by performing both of the above processes under appropriate processing conditions such as the above-described typical processing conditions.

FIG. 6 is a schematic view showing a state after the formation of terminals and element portions in the method of manufacturing a magnetic head of the present embodiment.

By the following steps S45 and S46, as shown in FIG. 6, a plurality of composite magnetic heads 30 finally formed on the wafer 11 are formed of the spin valve films of the read head 31 portions. An element portion 12; electrode terminals 7a and 7b which are positioned so as to sandwich the element portion 12 with a core width of about 1 μm therebetween and supply current to the element portion 12; and these electrode terminals 7a and 7
b, a wiring 13 for connecting one of the electrodes b to one of the adjacent electrode terminals 7a, 7b, and a terminal for collectively passing a current to each of the plurality of element portions 12 via the wiring 13 and the electrode terminals 7a, 7b. Outer peripheral terminal 8a,
8b is formed.

In step S45, portions other than the portions corresponding to the plurality of electrode terminals 7a and 7b, the wirings 12, and the outer peripheral terminals 8a and 8b of the wafer heat-treated in step S44 and having the spin valve film formed on one surface are formed. Is covered with a cover using a photoresist, Al ₂ O ₃ or the like, and the spin valve film corresponding to these terminals and wiring is removed by ion milling or the like. A hard magnetic film and a conductive film are sequentially laminated on the wafer from which portions corresponding to these terminals and wirings have been removed, and after such lamination, a cover over parts other than the terminals and wirings is removed. Thus, the plurality of electrode terminals 7a, 7b, wiring 12, and outer peripheral terminals 8a, 8b are formed on the hard magnetic film.
Is formed.

The hard magnetic film is made of, for example, CoCrPt, and the conductive film is made of, for example, 100.degree.
A Ti film having a thickness of 800 積 層 laminated on the Ti film
Au film laminated on this Au film and having a thickness of 200
And a film having a three-layer structure called a Ti film. It should be noted that such electrode terminals 7a, 7b
Is formed on the spin valve film so as to cover both end portions of the uppermost cap layer 6 of the spin valve film as shown in FIG.

In step S46, in addition to the plurality of electrode terminals 7a and 7b, the wiring 12, and the outer peripheral terminals 8a and 8b formed in step S45, these electrode terminals 7a
The portion corresponding to the element portion 12 sandwiched between the electrode portion 7b and the electrode portion 7b is covered with a photoresist, and ion milling or the like is performed to remove the spin valve film other than the portion corresponding to the element portion 12 from the wafer. The patterned element portion 12 is formed. This element part 1
2 corresponds to the magnetoresistive element according to the present invention.

In step S47, a reproducing upper gap film is formed on the spin valve film. This reproducing upper gap film is made of, for example, Al ₂ O ₃ .

In step S48, the reproducing upper shield 22 is formed on the reproducing upper gap. The reproducing upper shield is made of, for example, NiFe.

In step S49, a recording gap film 23 is formed on the reproduction upper gap. This recording gap film 23 is made of, for example, Al ₂ O ₃ .

In step S50, the recording gap film 23
The recording coil 25 is formed thereon while surrounding the periphery with an organic insulating material such as a resist. This recording coil 2
5 is made of, for example, Cu.

In step S51, the wiring 13 and the electrode terminal 7 are connected by the outer peripheral terminals 8a and 8b.
a, an organic insulating material surrounding the sensing current while flowing a current of a small current value than the current or the sense current I _s of the same current value as I _s, the recording coil 25 formed in step S50 to the element 12 through 7b Is heat-treated. This heat treatment is performed, for example, under a heating condition of a temperature of 275 ° C. for 3 hours. Here, the magnetic field generated at the position of the fixed side magnetic layer 4 by the current flowing through the element portion 12 causes
The direction of magnetization M _p of the fixed magnetic layer 4 is fixed to the x-direction.

In place of the heat treatment performed while applying a current in step S51, assuming that a conventional heat treatment is performed on the organic insulating material without passing a current through the element portion 12, in this case, Since the element height of the element portion 12 extending in the x direction is as small as about 5 μm, the magnetization M _p of the fixed-side magnetic layer 4 tilts in the y direction due to its own demagnetizing field even in the absence of a magnetic field. As a result, the reproduced waveform of the composite magnetic head finally formed has an external signal magnetic field H _sig
Does not respond linearly to the above, causing an obstacle such as distortion.

On the other hand, if a method of heating the organic insulating material while applying an external magnetic field in the same direction as the magnetization M _p of the fixed side magnetic layer so as to cancel the demagnetizing field is adopted, There is a problem that the direction of the axis of easy magnetization of the lower reproducing shield 21 and the upper reproducing shield 22 already formed in the process is rotated by 90 ° from the y direction and turned to the x direction.

However, in the magnetic head manufacturing method of the present embodiment, as described above, a current is applied to the element section 12 and the magnetization M _p of the fixed side magnetic layer 4 is utilized by utilizing a magnetic field locally generated by the current. Since the heat treatment of the organic insulating material is performed while canceling its own demagnetizing field, it hardly affects the direction of the easy axis of soft magnetic layers such as the free magnetic layer 2, the lower reproducing shield 21, and the upper reproducing shield 22. without the magnetization M _p of the fixed magnetic layer 4 can be fixed to the x-direction.

As described above, the magnetization M _p of the fixed-side magnetic layer 4 is set to x
In this case, the magnetization M _p of the fixed magnetic layer 4 is fixed.
And the direction of the easy axis of the soft magnetic layer such as the free side magnetic layer 2 can be made close to 90 °, so that the composite magnetic head manufactured by the magnetic head manufacturing method of the present embodiment can be made. Of the external signal magnetic field H _sig
, Which has an almost linear response to

In the case of performing the heat treatment as described above, it is not necessary to perform heating by the current, and the current value of the current flowing through the element portion 12 can be suppressed to a low value. The element portion 12 is not easily broken, and the yield in manufacturing the magnetic head is improved. Here, the current value I _s of the sense current safely flowed into the spin valve film in practical use of the reproducing head 31, the magnetic head manufacturing method of this embodiment, the current applied to the element 12 during the heat treatment It is a guide for the maximum current value.

In the process of heating the wafer while supplying a current to the element section 12 in this manner, the free magnetic layer 2 and the lower read shield 2
1. An external magnetic field may be applied to assist the direction of the easy axis of reproduction upper shield 22 to approach the y-direction. For example, the externally applied external magnetic field includes a magnetic field in the y direction. As described above, by applying the external magnetic field in a supplementary manner, the magnetic head manufacturing method of the present embodiment can more reliably control the direction of the axis of easy magnetization of a layer exhibiting soft magnetism such as the free magnetic layer 2. The direction of magnetization of the fixed-side magnetic layer 4 can be fixed. The magnetic field in the y direction is locally applied to the magnetization M _p of the free side magnetic layer 2 by the hard magnetic layer in contact with the free side magnetic layer 2, and this locally applied magnetic field is applied to the free side magnetic layer 2. It works to stabilize the easy axis of the magnetic layer in the y direction.

In step S 52, the upper recording magnetic pole 26 is formed on the recording coil 25. This upper recording magnetic pole 26
For example, it is made of NiFe.

In step S53, a protective film is formed on the upper recording magnetic pole. This protective film is made of, for example, Al ₂ O ₃ .

In step S54, the wafer on which the protective film has been formed in step S53 is divided so as to include the above-described element portions 12 one by one. The composite magnetic head 30 shown in FIG. 3 is formed on each of the divided wafers.

The method of manufacturing the reproducing head 31 corresponding to the method of manufacturing the magnetoresistive head according to the present invention is included in the method of manufacturing the composite magnetic head 30 described above. Step S47 above
The steps up to and including the step of performing the heat treatment while applying a current to the element section 12 in step S51 and the step of step S54 are added. However, here, step S5
The heat treatment 1 is not limited to the heat treatment of the organic insulating material. Further, the method of manufacturing the reproducing head 31 has the same effect as the method of manufacturing the composite type magnetic head 30 in that distortion of the reproduced waveform of the manufactured magnetic head is small and the yield in manufacturing the magnetic head is improved. Play.

[0081]

As described above, according to the present invention,
A method of manufacturing a magnetoresistive head with a small distortion of a reproduction waveform and improving the yield in the production of the magnetoresistive head, and a method of manufacturing a composite magnetic head with a small distortion of a reproduction waveform. Further, a method of manufacturing a composite magnetic head for improving the yield in manufacturing the composite magnetic head is provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a spin valve GMR head manufactured by a magnetic head manufacturing method according to an embodiment.

FIG. 2 is a side sectional view of the spin valve GMR head shown in FIG. 1;

FIG. 3 is a diagram showing a configuration of a composite magnetic head when applied to a hard disk device.

FIG. 4 is a view of the reproducing head as viewed from a magnetic disk side.

FIG. 5 is a flowchart illustrating a manufacturing process of the composite magnetic head.

FIG. 6 is a schematic view showing a state after forming terminals and element portions in the magnetic head manufacturing method of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Underlayer 2a 1st free side magnetic layer 2b 2nd free side magnetic layer 3 Nonmagnetic metal layer 4 Fixed side magnetic layer 5 Antiferromagnetic layer 6 Cap layer 7a, 7b Electrode terminal 8a, 8b Peripheral terminal 10 Spin Valve GMR head 10 'Spin valve film 11 Wafer 12 Element part 13 Wiring 20 Gap insulating film 21 Reproducing lower shield 22 Reproducing upper shield 22 Recording lower magnetic pole 23 Recording gap film 24 Organic insulating layer 25 Recording coil 26 Recording upper magnetic pole 27 Magnetic disk 30 Composite magnetic head 31 Reproduction head 32 Recording head

Continuing on the front page (72) Kenichi Aoshima 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Kenji Noma 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited (72) Inventor Naoki Mukaiyama 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa F-term within Fujitsu Limited (reference) 5D034 BA02 BA08 BA16 DA07

Claims (5)

[Claims] 1. A multilayer film including a free magnetic layer whose magnetization direction changes according to an external magnetic field and a fixed magnetic layer whose magnetization direction is fixed. A method of manufacturing a magnetoresistive head, comprising: a magnetoresistive element having a magnetoresistive effect element, wherein a sense current is passed through the magnetoresistive element and outputs a voltage that changes in accordance with the change in resistance. An element forming step of forming a plurality of magnetoresistive elements on the wiring, a wiring forming step of forming a wiring that collectively supplies current to the plurality of magnetoresistive elements formed in the element forming step, While performing a heat treatment on the magnetoresistive element, a current is collectively applied to each of the plurality of magnetoresistive elements through the wiring formed in the wiring forming step, and the fixed side of each of the magnetoresistive elements is fixed. A first magnetization direction fixing step of fixing the direction of magnetization of the magnetic layer. 2. In the first magnetization direction fixing step, when a current is collectively applied to each of the plurality of magnetoresistive elements, a region including the magnetoresistive elements is moved to a region including the magnetoresistive elements. 2. The method according to claim 1, wherein an external magnetic field is applied in a direction corresponding to the axis of easy magnetization. 3. After forming a plurality of magnetoresistive elements on a wafer in the element forming step, heating the plurality of magnetoresistive elements before performing the first magnetization direction fixing step. 2. The magnetoresistive effect according to claim 1, further comprising an easy axis control step of controlling the direction of the easy axis of the free magnetic layer of the magnetoresistive element by applying an external magnetic field in a predetermined direction. Mold head manufacturing method. 4. Applying an external magnetic field in a predetermined direction while heating the plurality of magnetoresistive elements formed in the element forming step before the easy axis control step, 4. The method of manufacturing a magnetoresistive head according to claim 3, further comprising a second magnetization direction fixing step of fixing the magnetization direction of the fixed side magnetic layer. 5. A multi-layered film including a free magnetic layer whose magnetization direction changes according to an external magnetic field and a fixed magnetic layer whose magnetization direction is fixed. A magneto-resistive head having a magneto-resistive effect element, wherein a sense current flows through the magneto-resistive element to output a voltage that changes in accordance with the resistance change, and a recording coil that generates a magnetic field from the recording coil A composite magnetic head manufacturing method for manufacturing a composite magnetic head in which a plurality of recording heads are combined, comprising: an element forming step of forming a plurality of magnetoresistive elements on a wafer; Forming a wiring for supplying a current to the magnetoresistive element collectively; and forming a recording coil of the recording head by surrounding the recording coil with an organic insulating material. Coil forming step, while curing the organic insulating material surrounding the recording coil formed in the coil forming step by heat treatment,
A magnetization direction fixing step of passing a current collectively through each of the plurality of magnetoresistive elements through the wiring formed in the wiring forming step and fixing the magnetization direction of the fixed side magnetic layer of each of the magnetoresistive elements. A method for manufacturing a composite magnetic head, comprising: