JP2000348313A - Production of spin valve film and production of magnetoresistive magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an antiferromagnetic film thinner and to minimize the degradation in characteristics by a heat treatment. SOLUTION: This process for producing the spin valve film formed by laminating a first magnetic film, a nonmagnetic film, a second magnetic film and the antiferromagnetic film formed by a Pt-Mn alloy consists in subjecting the antiferromagnetic film to the heat treatment within a range enclosed by four points; the point A (280 deg.C, 15 nm), point B (310 deg.C, 15 nm), point C (280 deg.C, 30 nm) and the point D (280 deg.C, 30 nm) in a graph with which the heat treatment temperature of the antiferromagnetic film is taken at the abscissa and the thickness of the antiferromagnetic film as the ordinate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a spin valve film, which is a kind of a magnetoresistive element. The present invention also relates to a method for manufacturing a magnetoresistive head having a spin valve film as a magnetic sensing element for detecting a magnetic signal from a magnetic recording medium.

[0002]

2. Description of the Related Art A magnetoresistive element is an element whose resistance value changes according to the magnitude of an external magnetic field, and is used, for example, as a magneto-sensitive element for detecting a magnetic signal from a magnetic recording medium in a magnetic head. A magnetic head provided with this magnetoresistive element is generally called a magnetoresistive magnetic head (hereinafter referred to as an MR head).

[0003] Conventionally, as a magnetoresistive element, a Ni—Fe alloy film or a Ni—Co alloy exhibiting an anisotropic magnetoresistive effect has been used.
A magnetoresistive element using an alloy film or the like has been widely used. However, since the above-described conventional magnetoresistance effect element has a small magnetoresistance change rate, a magnetoresistance effect element exhibiting a larger magnetoresistance change rate is desired.

Therefore, as a magnetoresistive element exhibiting a larger magnetoresistance change rate, a pair of magnetic films are joined via a nonmagnetic film, and an antiferromagnetic film is joined on one of the magnetic films.
A so-called spin valve film has been proposed.

[0005] For example, as shown in FIG.
Are arranged in a reproducing gap 101 made of a non-magnetic material. The spin valve film 100 has a first
Magnetic film 102, non-magnetic film 103, and second magnetic film 1
04 and the antiferromagnetic film 105 are laminated in this order. In the spin valve film 100, the second magnetic film 10
4 is disposed in contact with the antiferromagnetic film 105,
Due to the exchange coupling magnetic field acting between the antiferromagnetic film 105 and the antiferromagnetic film 105, the film is magnetized in a certain direction (hereinafter, referred to as "magnetized").
Such a second magnetic film 104 is referred to as a pinned layer 104. ). On the other hand, the first magnetic film 102 is a non-magnetic film 103
And the second magnetic film 104 is separated from the second magnetic film 104, the magnetic direction is easily rotated even by a weak external magnetic field (hereinafter, such a first magnetic film 102 is free layer). 102).

In the MR head constructed as described above,
When an external magnetic field is applied, the magnetization direction of the free layer 102 is determined according to the direction and strength of the external magnetic field. In the MR head, when the magnetization direction of the pinned layer 104 is 180 ° opposite to the magnetization direction of the free layer 102, the electric resistance becomes maximum. On the other hand, when the magnetization direction of the pinned layer 104 is the same as the magnetization direction of the free layer 102, the electric resistance is minimized.

[0007] Therefore, in the MR head, since the electric resistance changes according to the external magnetic field applied to the magnetic recording medium, the external magnetic field can be detected by reading the resistance change.

[0008]

The above-mentioned M
In the R head, as the recording density of the magnetic recording medium increases,
It is necessary to reduce the gap G of the reproducing gap 101, that is, the so-called reproducing gap length. Therefore, in the MR head, it is desired that the spin valve film 100 be formed as thin as possible.

However, in the MR head, the thicknesses of the free layer 102 and the pinned layer 104 of the spin valve film 100 serving as the magnetic sensing portion are naturally limited in terms of Ms, magnetic characteristics, and ESD characteristics. In the MR head, as shown in FIG. 14, the free layer 102 constituting the spin valve film 100 is configured to be located substantially at the center of the reproducing gap 101. For this reason, in the MR head, if the thickness of the antiferromagnetic film 105 is too large, the thickness S of the reproducing gap 101 on the antiferromagnetic film 104 side becomes too small, and it is necessary to secure insulation at this portion. Problems will arise. Therefore, in the MR head, the critical thickness of the antiferromagnetic film 105 has been regarded as a problem.

Here, as the antiferromagnetic film, a regular antiferromagnetic film made of a regular alloy exhibiting antiferromagnetic properties at the stage of film formation, and a heat treatment after film formation, Of an irregular antiferromagnetic film made of an irregular alloy exhibiting properties
Types. Among them, the irregular antiferromagnetic film is
In terms of characteristics, it is superior to an ordered antiferromagnetic film.
On the other hand, the disordered antiferromagnetic film must be regularized by heat treatment. Therefore, in order to promote ordering and secure characteristics, the antiferromagnetic random film needs to have a certain thickness.

For this reason, in the conventional MR head, when the thickness of the irregular antiferromagnetic film is too small, the antiferromagnetic film is not ordered by the heat treatment, and good characteristics cannot be obtained. There was a problem.

In view of the foregoing, the present invention has been proposed in view of the above-mentioned circumstances, and a spin valve film having a thinner antiferromagnetic film and minimizing deterioration in characteristics due to heat treatment has been proposed. It is intended to provide a manufacturing method. Another object of the present invention is to provide a method of manufacturing a magnetoresistive head having such a spin valve film.

[0013]

According to the present invention, there is provided a method of manufacturing a spin valve film, comprising: a first magnetic film, a non-magnetic film, a second magnetic film, and a Pt-Mn alloy; A method for manufacturing a spin valve film in which the formed antiferromagnetic film and the antiferromagnetic film are stacked, wherein a horizontal axis represents the heat treatment temperature of the antiferromagnetic film, and a vertical axis represents the thickness of the antiferromagnetic film. Point A (280 ° C., 15 nm), Point B (310 ° C., 1 nm)
5 nm), point C (280 ° C., 30 nm), point D (250
(.Degree. C., 30 nm) in a range surrounded by four points.

As described above, in the method of manufacturing the spin valve film according to the present invention, the thickness of the antiferromagnetic film is reduced, and a high exchange coupling magnetic field is obtained after the heat treatment.

In order to achieve the above object, a method of manufacturing a magneto-resistance effect type magnetic head according to the present invention is characterized in that a first magnetic film and a non-magnetic film are used as a magnetic sensing element for detecting a magnetic signal from a magnetic recording medium. And a second magnetic film, and a method of manufacturing a magnetoresistive magnetic head having a spin valve film formed by laminating an antiferromagnetic film formed of a Pt—Mn alloy, wherein the antiferromagnetic film In the graph in which the horizontal axis represents the heat treatment temperature with respect to and the vertical axis represents the thickness of the antiferromagnetic film, the point A (2
80 ° C., 15 nm), point B (310 ° C., 15 nm), point C (280 ° C., 30 nm), point D (250 ° C., 30 n)
m) heat-treating the antiferromagnetic film in a range surrounded by the four points.

As described above, in the method of manufacturing a magnetoresistive head according to the present invention, the thickness of the antiferromagnetic film is reduced, and a high exchange coupling magnetic field is obtained after the heat treatment. For this reason, the output characteristics of the manufactured magnetic head are improved.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, a method of manufacturing the spin valve film 1 shown in FIG. 1 will be described as an embodiment of the present invention.

As shown in FIG. 1, the spin valve film 1 includes a first magnetic film 3, a non-magnetic film 4, a second magnetic film 5, and an anti-ferromagnetic film 6 on a substrate 2. Are stacked in this order. The substrate 2 is made of, for example, Al ₂ O ₃ , Al ₂ O ₃ —TiC
(Altic), diamond-like carbon (DL
It is formed in a substantially flat plate shape from a hard non-magnetic non-conductive material such as C).

The first magnetic film 3 is formed on the substrate 2 by a magnetic material exhibiting good soft magnetic properties such as a Ni—Fe alloy, a Co—Fe alloy, a Co—Ni—Fe alloy, for example. . The first magnetic film 3 is made of, for example, Ni-F
It may be formed by a laminated structure of an e alloy and a Co—Fe alloy. Thereby, spin-dependent scattering in the first magnetic film 3 can be suppressed.

The non-magnetic film 4 is made of, for example, Cu, Cu-Ni
The first magnetic layer 3 is formed of a non-magnetic material such as an alloy.

The second magnetic film 5, like the first magnetic layer 3, is formed on the non-magnetic film 4 by a magnetic material exhibiting good soft magnetic characteristics.

The antiferromagnetic film 6 is made of Pt-
It is formed on the second magnetic film 5 using an antiferromagnetic material made of a Mn alloy.

In this spin valve film 1, since the second magnetic film 5 is disposed in contact with the antiferromagnetic film 6,
Due to the exchange coupling force acting between the antiferromagnetic film 6 and the antiferromagnetic film 6, it is magnetized in a certain direction (hereinafter, such a second magnetic film 5 is referred to as a pinned layer 5). Meanwhile, the first
Since the magnetic film 3 is disposed separately from the free layer 5 via the non-magnetic film 4, the magnetization direction easily rotates even with a weak external magnetic field (hereinafter, such a first magnetic field). Is referred to as a free layer 3).

The spin valve film 1 constructed as described above
When an external magnetic field is applied, the magnetization direction of the free layer 3 is determined according to the direction and strength of the external magnetic field. The electrical resistance of the spin valve film 1 becomes maximum when the magnetization direction of the pinned layer 5 and the magnetization direction of the free layer 3 are 180 ° opposite to each other. The electrical resistance of the spin valve film 1 is minimized when the magnetization direction of the pinned layer 5 and the magnetization direction of the free layer 3 are the same.

Therefore, in the spin valve film 1, since the electric resistance changes according to the applied external magnetic field, the external magnetic field can be detected by reading the resistance change.

In the spin valve film 1, the substrate 2
A base layer made of, for example, Ta or the like may be formed between the first free layer 3 and the free layer 3 as a base. In the spin valve film 1, a protective film made of, for example, Ta may be formed on the antiferromagnetic film 6. By forming the spin valve film 1 with a base layer and a protective film, an increase in specific resistance can be prevented.

Further, in the above description, the spin valve film 1 comprises the first magnetic film 3 and the non-magnetic film 4
And the second nonmagnetic film 5 and the antiferromagnetic film 6 are stacked in this order, but the present invention is not limited to such a structure. For example, in the spin valve film 1, the substrate 2
An antiferromagnetic film 6 and a second nonmagnetic film (pin layer) 5
, A non-magnetic film 4 and a first magnetic film (free layer) 3 may be laminated in this order.

The spin valve film 1 has a laminated structure in which each of the above-described films is formed with a very small thickness of about several nm. Therefore, it is desirable that the spin valve film 1 is formed using an ultra-high vacuum sputtering apparatus. Thereby, the spin-valve film 1 can improve the quality of each film and can accurately form the thickness of each film.

FIG. 2 shows an example of an ultra-high vacuum sputtering apparatus. This ultra-high vacuum sputtering apparatus 10 has three chambers: a substrate preparation chamber 11, a preliminary process chamber 12 for cleaning a substrate by reverse sputtering, and a film formation chamber 13 capable of performing film formation by sputtering under reduced pressure. It has a structure. Note that the ultimate vacuum degree of the background in the film forming chamber 13 can be, for example, about 1.0 × 10 ⁻⁹ Pa.

The ultra-high vacuum sputtering apparatus 10 uses an inductively-coupled RF plasma-assisted magnetron cathode as a sputtering cathode 14, and an RF coil is arranged on a target. Thus, discharge can be performed even under a low gas pressure, and a high ionization rate can be obtained.

Further, a plurality of sputtering cathodes 14 are provided in the film forming chamber 13 of the ultra-high vacuum sputtering apparatus 10. When the above-described spin valve film 1 is manufactured, for example, a Ni—Fe target, a Cu target, a Pt—M
n targets are arranged and used.

When manufacturing the spin valve film 1, the substrate 2 is placed in the film forming chamber 13, and a vacuum pump (not shown) is used.
The pressure inside the film forming chamber 13 is sufficiently reduced by, for example, 5 × 10
^-8 Torr or less. Then, Ar gas is introduced while adjusting the degree of vacuum in the film forming chamber 13. Then, a positive voltage is applied to an anode plate (not shown) on which the substrate 2 is arranged,
For example, a negative voltage is applied to the sputtering cathode 14 on which a Ni—Fe target is provided. This gives N
High purity Ar is made to collide with an i-Fe target to produce Ni-F
e, and a first magnetic film 3 made of Ni—Fe is laminated on the substrate 2.

Next, a positive voltage is applied to the anode plate, and for example, the sputtering cathode 1 on which a Cu target is provided is provided.
4 is applied with a negative voltage. Thereby, the first magnetic layer 3
A non-magnetic film 4 made of Cu is further laminated thereon.

Next, a positive voltage is applied to the anode plate, and a negative voltage is applied to the sputtering cathode 14 provided with, for example, a Ni—Fe target. Thereby, the second magnetic film 5 made of a Ni—Fe alloy is further formed on the nonmagnetic layer 4.
Are laminated.

Next, a positive voltage is applied to the anode plate, and a negative voltage is applied to the sputtering cathode 14 on which, for example, a Pt-Mn target is provided. Thus, an antiferromagnetic film 6 made of a Pt—Mn alloy is further laminated on the second magnetic film 5.

The spin valve film 1 is manufactured as described above, so that the first magnetic film 3, the non-magnetic film 4, the second magnetic film 5, the anti-ferromagnetic film 6 are laminated in this order.

In the manufacturing process of the spin valve film 1 described above, a target material may be provided for each sputtering cathode 14 according to the material for forming each film.

In the spin valve film 1, the antiferromagnetic film 6 is made of a Pt-Mn alloy which is an irregular alloy. This Pt-Mn alloy has excellent thermal stability and has properties superior to those of the ordered alloy. However,
When producing the spin valve film 1, the Pt-M
It is necessary to perform a heat treatment for ordering the antiferromagnetic film 6 made of the n alloy.

Therefore, it was confirmed that the critical film thickness of the antiferromagnetic film was reduced while maintaining the characteristics of the spin valve film. Hereinafter, a result of examining how the characteristics of the spin valve film change by changing the heat treatment conditions of the antiferromagnetic film constituting the spin valve film will be described.

First, the heat treatment time is, for example, 1 hour (h), the thickness of the antiferromagnetic film is, for example, 30 nm, and the heat treatment temperature is, for example, 230 ° C., 250 ° C., 280 ° C., 310 ° C.
The dependence of the antiferromagnetic film on the heat treatment temperature of the spin valve film when the temperature was changed to ° C was investigated. In addition,
FIG. 3 is a graph showing the relationship between the change in the external magnetic field and the rate of change in resistance of the spin valve films manufactured by changing the heat treatment temperature.

As is clear from FIG.
It can be seen that in the spin valve film set at 30 ° C., the heat treatment temperature was too low, so that the antiferromagnetic film was not ordered and did not exhibit properties as an antiferromagnetic film. Further, it can be seen that even a spin valve film having a heat treatment temperature of 250 ° C. does not exhibit favorable characteristics because the heat treatment temperature is low and the ordering of the antiferromagnetic film is insufficient.

On the other hand, in the spin valve film in which the heat treatment temperature is 280 ° C., the magnitude of the exchange coupling magnetic field H _pin between the antiferromagnetic film and the layer that is exchange-coupled is increased due to the ordering of the antiferromagnetic film.
It can be seen that H _pin > 800 (Oe). Further, even in a spin valve film having a heat treatment temperature of 310 ° C.,
H _pin > 800 (Oe), which indicates that preferable characteristics are exhibited. Further, it can be seen that this spin valve film has a larger rate of change in resistance than the spin valve film in which the heat treatment temperature is set to 280 ° C., and shows excellent characteristics.

As described above, it can be seen that in the spin valve film, the characteristics of the antiferromagnetic film change significantly depending on the heat treatment temperature.

Next, the heat treatment temperature of the antiferromagnetic film
For example, the temperature is set to 250 ° C. and the thickness of the antiferromagnetic film is set to, for example, 30 n
m, the heat treatment time is, for example, 1 h, 4 h, 5 h, 1
The dependence on the heat treatment time of the antiferromagnetic film in the spin valve film when the time was changed to 5 h was examined. FIG. 4 is a graph showing the relationship between the change in the external magnetic field and the rate of change in resistance of the spin valve films manufactured by changing the heat treatment time.

As is apparent from FIG.
It can be seen that in the spin valve film of h, since the heat treatment time was too short, the ordering of the antiferromagnetic film was insufficient, and the spin valve film did not exhibit desirable characteristics as an antiferromagnetic film.

On the other hand, in the case of a spin valve film in which the heat treatment time is 4 hours, H _pin > 800 due to the regularization of the antiferromagnetic film.
(Oe), which indicates that preferable characteristics are exhibited. Also, a spin valve film having a heat treatment time of 5 hours,
Regarding the spin valve film having a heat treatment time of 15 hours,
H _pin > 800 (Oe), which indicates that preferable characteristics are exhibited. Among these, it can be seen that the spin valve film having the heat treatment time of 4 hours has a larger resistance change rate than the other spin valve films and exhibits excellent characteristics.

As described above, with respect to the problem of reducing the critical film thickness of the antiferromagnetic film while maintaining the characteristics of the antiferromagnetic film in the spin valve film, these heat treatment conditions can be optimized. It has been found that the thickness of the antiferromagnetic film can be reduced.

Therefore, the antiferromagnetic film tends to be ordered as the film thickness increases, but from the viewpoint of thinning, the antiferromagnetic film tends to be more ordered.
nm or less, and the characteristics of the spin valve film are H _pin > 80.
0 (Oe), by obtaining a good range of the H _f <12 (Oe), made it possible to thin the antiferromagnetic film to 15 nm.

FIG. 5 shows the relationship between the heat treatment temperature and the film thickness of the antiferromagnetic film. FIG. 5 is a graph in which the horizontal axis represents the heat treatment temperature of the antiferromagnetic film and the vertical axis represents the thickness of the antiferromagnetic film.

The heat treatment time is more easily regulated as the thickness of the antiferromagnetic film is larger. If the heat treatment is excessive, the heat treatment may be diffused to lower the output of the magnetic head. The time was 4 hours. However, the heat treatment time is not necessarily limited, and it is preferable to perform the heat treatment to such an extent that thermal deterioration does not occur.

FIG. 5 shows that the above-mentioned heat treatment time is 1
h, H _pin > 800 (Oe), H _f
<12 (Oe) is also added.

As a result, as shown in FIG.
0 ° C., 15 nm), point B (310 ° C., 15 nm), point C
(280 ° C., 30 nm), point D (250 ° C., 30 nm)
By performing heat treatment on the antiferromagnetic film within the range surrounded by the four points, a high exchange coupling magnetic field of H _pin > 800 (Oe) is obtained after the heat treatment while maintaining the characteristics of the antiferromagnetic film. It became clear that we could do that.

As described above, in the method of manufacturing the spin valve film to which the present invention is applied, by optimizing the heat treatment conditions of the antiferromagnetic film, the characteristics of the antiferromagnetic film can be maintained.
It can be thinned.

Next, a method of manufacturing the magnetoresistive head according to the present invention will be described. This method, for example,
This is applied when manufacturing a magnetoresistive head 20 (hereinafter referred to as an MR head 20) as shown in FIG. Therefore, first, the MR head 20 manufactured by applying the present invention will be described. FIG. 6 shows the MR head 2
0 is a side view of the magnetic recording medium as viewed from the sliding surface side. Further, in the following description, specific examples of each member constituting the MR head 20 and its material, size, film thickness, film forming method, and the like will be described, but the present invention is not limited to the following examples. Absent.

The MR head 20 is made of, for example, Al ₂ O ₃ —Ti
A substrate 21 formed of a hard non-magnetic material such as C (altic) in a substantially flat plate shape, a first non-magnetic layer 22 formed on the substrate 21, and a first non-magnetic layer 22 formed on the first non-magnetic layer 22; Lower magnetic shield layer 2 having substantially the same height.
The third and second nonmagnetic layers 24, the third nonmagnetic layer 25 formed on the lower magnetic shield layer 23 and the second nonmagnetic layer 24, and the third nonmagnetic layer 25 The formed magnetoresistive element 26 (hereinafter, referred to as MR element 26) and a pair of electrodes 27, and the third nonmagnetic layer 25 formed on the third nonmagnetic layer 25 on which the MR element 26 and the pair of electrodes 27 are formed. 4 and a middle magnetic shield layer 29 formed on the fourth nonmagnetic layer 28 immediately above the MR element 26.

The MR head 20 has a second non-magnetic layer 24, a third non-magnetic layer 25, and a third non-magnetic layer 25 between the lower magnetic shield layer 23 and the intermediate magnetic shield layer 29 on the sliding surface of the magnetic recording medium. By disposing the four nonmagnetic layers 28,
A reproduction gap is formed with the MR element 26 interposed therebetween.

In the MR head 20, an inductive head is formed on the intermediate magnetic shield layer 29 as a recording head. The inductive head has a fifth magnetic head formed on the intermediate magnetic shield layer 29 such that the end on the sliding surface side of the magnetic recording medium has a predetermined thickness.
A non-magnetic layer 30, a thin-film coil (not shown) formed in the fifth non-magnetic layer 30, and a fifth non-magnetic layer 30
An upper magnetic shield layer 31 formed on the upper surface and in contact with the intermediate magnetic shield layer 29 substantially near the center of the thin film coil.

In this inductive head, a magnetic core is formed by an intermediate magnetic shield layer 29 and an upper magnetic shield layer 31, and the intermediate magnetic shield layer 29 and the upper magnetic shield layer are formed on the sliding surface of the magnetic recording medium. By disposing the fifth non-magnetic layer 30 between the first non-magnetic layer 31 and the first magnetic layer 31, a magnetic gap is formed.

The MR head 20 is formed by laminating the above-described layers and members in the form of a thin film on a substrate 21.
Further, in the MR head 20, the above-mentioned layers and members face outward on the sliding surface of the recording medium, and constitute substantially the same surface. The MR head 20 has a structure in which an MR element 26 is sandwiched between a lower magnetic shield layer 23 and an intermediate magnetic shield layer 29, and is configured as a so-called horizontal MR head.

The first non-magnetic layer 22 is formed of a non-magnetic material on the substrate 2 and has a thickness of, for example, 30 μm. In the present embodiment, the first non-magnetic layer 2
As No. 2, for example, Al ₂ O ₃ was formed with a thickness of 5 μm.

The lower magnetic shield layer 23 is formed of the MR head 2
The first non-magnetic layer 22 is formed on the first non-magnetic layer 22 so as to reach a predetermined width from the sliding surface of the recording medium at 0. The lower magnetic shield layer 23 is made of, for example, Fe-Al-Si alloy (Sendust), Fe-Si-Ru-Ga alloy, Fe-Ta-
A metal magnetic layer having high heat resistance such as N alloy and exhibiting good soft magnetic characteristics is formed with a thickness of 3 to 5 μm.
In the present embodiment, sendust is formed as the lower magnetic shield layer 23 by a dry etching method.

The second non-magnetic layer 24 is formed on the first non-magnetic layer 22 with substantially the same thickness as the lower magnetic shield layer 23 so as to form substantially the same plane as the lower magnetic shield layer 23. I have. The second non-magnetic layer 24 is formed of a non-magnetic material such as, for example, Al ₂ O ₃ .

The third nonmagnetic layer 25 is formed with a thickness of about 0.3 to 0.5 μm on the lower magnetic shield layer 23 and the second nonmagnetic layer 24 constituting substantially the same plane. The third non-magnetic layer 25 is formed of a non-magnetic material having an electrical insulating property so that a current flowing through the MR element 26 and the pair of electrodes 27 is not short-circuited.

The MR element 26 has a lower magnetic shield layer 23
Is formed on the third nonmagnetic layer 25 in a substantially rectangular shape. The MR element 26 is arranged so that its longitudinal direction is perpendicular to the in-plane direction of the magnetic recording medium.

The MR element 26 has the same film structure as the spin valve film 1 described above, and includes a first magnetic layer, a non-magnetic layer, a second magnetic layer, and an antiferromagnetic layer. Are so-called spin-valve MR elements having a structure laminated in this order.

The pair of electrodes 27 are respectively connected to both ends of the MR element 26 in the longitudinal direction. A pair of electrodes 27
Are formed for the purpose of supplying a sense current along the longitudinal direction of the MR element 26, and are formed of a conductive material. The thickness of the pair of electrodes 27 is slightly larger than the thickness of the MR element 26.

The fourth nonmagnetic layer 28 is formed of a nonmagnetic insulating material on the third nonmagnetic layer 25 on which the MR element 26 and the pair of electrodes 27 are formed. In other words, in the MR head 20, the MR element 26 and the pair of electrodes 27 are formed by the second nonmagnetic layer 25 and the fourth nonmagnetic layer 2.
8 and is sandwiched between them. Further, since the fourth nonmagnetic layer 28 is formed of a material that is nonmagnetic and has electrical insulation properties,
The current flowing through the MR element 26 and the pair of electrodes 27 is not short-circuited.

The intermediate magnetic shield layer 29 is formed of the MR head 1
In order to face a predetermined width from the sliding surface of the recording medium in,
It is formed on the fourth nonmagnetic layer 28. The intermediate magnetic shield layer 29 is similar to the magnetic shield layer 23 described above.
It is made of a metallic magnetic material exhibiting good soft magnetic properties, and is formed by a film forming method such as sputtering.

In the MR head 20, the lower magnetic shield layer 23 and the intermediate magnetic shield layer 29 function to prevent a magnetic field outside the target of reproduction from being drawn into the MR element 26 among signal magnetic fields from the magnetic recording medium. . That is, MR
In the head 20, since the lower magnetic shield layer 23 and the intermediate magnetic shield layer 29 are disposed above and below the MR element 26 via the third nonmagnetic layer 25 and the fourth nonmagnetic layer 28, Of the signal magnetic field from the magnetic recording medium, a magnetic field outside the reproduction target is guided to the lower magnetic shield layer 23 and the intermediate magnetic shield layer 29, and only the reproduction target signal magnetic field is drawn into the MR element 26.

Therefore, in the MR head 9, the M of the lower magnetic shield layer 23 and the intermediate magnetic shield layer 29
The interval in the R element 26 is a so-called reproduction gap length. That is, in the MR head 20, the total thickness of the third non-magnetic layer 25 and the fourth non-magnetic layer 28 is the read gap length.

The fifth non-magnetic layer 30 is formed on the fourth non-magnetic layer 28 on which the intermediate magnetic shield layer 29 has been formed.
It is formed of a non-magnetic material. Fifth nonmagnetic layer 3
A thin-film coil (not shown) is formed in 0.

The upper magnetic shield layer 31 is formed on the fifth non-magnetic layer 30 just above the intermediate magnetic shield layer 29 and is made of a magnetic material.

In the MR head 20, as described above, the intermediate magnetic shield layer 29 and the fifth non-magnetic layer 30
, The thin-film coil, and the upper magnetic shield layer 31 constitute an inductive head as a recording head.

In the MR head 20 configured as described above, a constant sense current is supplied to the MR element 26 when reproducing a magnetic signal recorded on the magnetic recording medium. In this MR head 20, the MR element 2
6 changes according to the signal magnetic field from the magnetic recording medium. Therefore, in the MR head 1, when a constant current is supplied to the MR element 26,
The voltage value of the sense current changes based on the change in the resistance value of the element 26. Therefore, in this MR head 20, the signal magnetic field from the magnetic recording medium can be detected by measuring the change in the voltage value of the sense current.

When recording a magnetic signal on a magnetic recording medium, the MR head 20 has an intermediate magnetic shield layer 29.
A current corresponding to the recording signal is supplied to the thin film coil of the inductive head formed above. In this inductive head, a magnetic flux flows through a magnetic core formed by the intermediate magnetic shield layer 29 and the upper magnetic shield layer 31 by a magnetic field generated from the thin film coil. Thereby, in the inductive head, a leakage magnetic field is generated in the magnetic gap formed by the intermediate magnetic shield layer 29, the fifth nonmagnetic layer 30, and the upper magnetic shield layer 31. The inductive head records the magnetic signal by applying the leakage magnetic field to the magnetic recording medium.

When manufacturing the above-described MR head 20, first, as shown in FIG. 7, for example, Al ₂ O ₃ —TiC
A substrate material 40 made of a hard non-magnetic material such as (Altic) or the like is formed in a substantially flat plate shape, and the main surface 40a of the substrate material 40 is mirror-polished. The substrate material 40 eventually becomes the substrate 21 of the MR head 20, and a number of head elements of the MR head 20 are formed on the main surface 40a, as described later.

Next, as shown in FIG. 8, on the main surface 40a of the substrate material 40, the first
Is formed. In the present embodiment,
As the first nonmagnetic film 41, Al ₂ O ₃ was formed to a thickness of 5 μm. In the present embodiment, the first nonmagnetic film 41 is polished after the film formation so that the surface of the first nonmagnetic film 41 becomes smooth.

Next, as shown in FIG. 9, on the first non-magnetic film 41, the first
Of the magnetic film 42 is formed. The first magnetic film 42 is made of, for example, Fe-Al-Si alloy (Sendust), Fe-Si-R
The film is formed of a material exhibiting good soft magnetic characteristics, such as a u-Ga alloy and an Fe-Ta-N alloy. In the present embodiment, when the first magnetic film 42 is formed, sendust is formed to a thickness of about 3 to 5 μm by a dry etching method using a resist pattern.

Next, as shown in FIG. 10, on the first non-magnetic film 41 on which the first magnetic film 42 is formed, a non-magnetic film 43 which will eventually become the second non-magnetic layer 24 is formed. Is formed. Second
The non-magnetic film 43 is formed of a non-magnetic material such as diamond-like carbon (DLC) or Al ₂ O ₃ . In the present embodiment, diamond-like carbon was formed to a thickness of about 3 to 5 μm by a high frequency sputtering method. At this time, the first magnetic film 42
The second nonmagnetic film 43 may be formed while applying a magnetic field from the outside in order to control the magnetic characteristics of the second nonmagnetic film 43.

Next, as shown in FIG. 11, the second non-magnetic film 43 is polished to expose the first magnetic film 42 embedded in the second non-magnetic film 43. . That is, the second magnetic film is polished so that the first magnetic film 42 and the second nonmagnetic film 43 form the same surface.

At this time, it is desirable that the first magnetic film 42 and the second non-magnetic film are polished until the surface roughness becomes 1 nm or less. Thus, the thickness of the third nonmagnetic film 25 formed in a later step can be formed with high accuracy.

Next, as shown in FIG. 12, on the first magnetic film 42 and the second non-magnetic film 43 forming the same surface,
Third non-magnetic film 44 that finally becomes third non-magnetic layer 25
Is formed. In the present embodiment, diamond-like carbon (DLC) is formed as the third nonmagnetic film 4 to have a thickness of 0.3 to 0.5 μm by a high-frequency plasma method. At this time, in order to control the magnetic characteristics of the first magnetic film 42, the third nonmagnetic film 44 may be formed while applying a magnetic field from the outside. After forming the third non-magnetic film 44, the surface roughness of the third non-magnetic film 44 is 1 nm.
It is desirable to polish to the following degree. Thus, in a later step, the thickness and the like of the MR thin film 45 and the pair of electrodes 46 formed on the third nonmagnetic film 44 can be accurately formed. Thereby, the reproduction efficiency of the MR head 20 finally completed can be improved.

Next, as shown in FIG. 13, on the third nonmagnetic film 44, a thin film (hereinafter referred to as MR) constituting the MR element 26 is formed.
It is called a thin film 45. ) Is formed by sputtering or the like. The MR thin film 45 is formed in the same manner as in the method of manufacturing the spin valve film 1 described above. That is, for example, by using a sputtering apparatus such as the above-described ultra-high vacuum sputtering apparatus 10,
A first magnetic film (free layer), a non-magnetic film, a second magnetic film (pinned layer), and an antiferromagnetic film are sequentially formed on the third non-magnetic film 44.

Then, the antiferromagnetic film is formed of the above-mentioned Pt-Mn.
In a graph having an irregular antiferromagnetic film made of an alloy, the heat treatment temperature of the antiferromagnetic film as abscissa and the thickness of the antiferromagnetic film as ordinate, a point A (280 ° C., 15 nm), B
(310 ° C., 15 nm), point C (280 ° C., 30 n
m) and heat treatment is performed on the antiferromagnetic film in a range surrounded by the four points of point D (250 ° C., 30 nm) to maintain the characteristics of the antiferromagnetic film while maintaining the H _pin after the heat treatment.
A high exchange coupling magnetic field of> 800 (Oe) can be obtained. Therefore, the output characteristics of the manufactured MR head 20 are improved.

Next, a pair of electrodes 46 is formed on both ends of the MR thin film 45. The pair of electrodes 26 are respectively formed on both ends in the longitudinal direction of the MR thin film 45 by using a conductive material such as Cu, for example, by a method such as an evaporation method or a sputtering method.

Next, the fourth nonmagnetic layer 2 is formed on the third nonmagnetic film 44 on which the MR thin film 45 and the pair of electrodes 46 are formed.
A fourth non-magnetic film 47 constituting 8 is formed. The fourth nonmagnetic film 47 is formed from a nonmagnetic insulating material such as Al ₂ O ₃ by a method such as sputtering.

Next, a second magnetic film 48 constituting the intermediate magnetic shield layer 29 is formed on the fourth non-magnetic film 47. The second magnetic film 48 is formed from a material exhibiting good soft magnetic characteristics by a technique such as sputtering.

Next, a fifth non-magnetic film 49 constituting the fifth non-magnetic layer 30 is formed on the second magnetic film 48. The fifth nonmagnetic film 49 is formed from a nonmagnetic material such as Al ₂ O ₃ by a method such as sputtering. At this time, a thin-film coil (not shown) is formed in the fifth nonmagnetic film 49. The thin-film coil is formed in a spiral shape in the fifth non-magnetic film 49 with a connection portion between a third magnetic film 50 and a second magnetic film 48 described later being substantially at the center.

Next, a third magnetic film 50 constituting the upper magnetic shield layer 31 is formed on the fifth nonmagnetic film 49. The third magnetic film 50 is formed from a material exhibiting good soft magnetic characteristics by a technique such as sputtering. Third
The magnetic film 50 is formed so as to be connected to the second magnetic film 48 substantially near the center of the thin film coil. As a result, the third
The magnetic film 50 and the second magnetic film 48 are
, A magnetic core of an inductive head as a recording head is formed.

In the method of manufacturing a magnetoresistive head according to the present invention, the MR head 20 is manufactured as described above. According to this manufacturing method, the thickness of the antiferromagnetic film can be reduced while maintaining the characteristics of the antiferromagnetic film. Therefore, according to this manufacturing method, the MR thin film 4
5 can be formed thin, and the above-described reproduction gap length can be narrowed, and an MR head corresponding to a high recording density of a magnetic recording medium can be manufactured. Further, since the thickness of the antiferromagnetic film is reduced, the thickness of the fourth nonmagnetic layer 28 in the reproducing gap can be maintained, and the insulating property of the fourth nonmagnetic layer 28 can be improved. Can be.

In the manufacturing process of the MR thin film 45, an underlayer may be formed between the third nonmagnetic film 44 and the first magnetic layer using, for example, Ta. Further, a protective layer may be formed on the antiferromagnetic layer by, for example, Ta. Thus, the MR thin film 4 having the underlayer and the protective layer is provided.
By forming the film 5, the increase in the specific resistance of the MR thin film 45 can be prevented.

[0093]

As described above, according to the spin valve film manufacturing method of the present invention, the characteristics of the antiferromagnetic film are maintained by optimizing the heat treatment conditions of the antiferromagnetic film. In addition, the thickness of the antiferromagnetic film can be reduced.

According to the method of manufacturing a magneto-resistance effect type magnetic head of the present invention, by optimizing the heat treatment conditions for the antiferromagnetic film, the characteristics of the antiferromagnetic film can be maintained while maintaining the characteristics of the antiferromagnetic film. The magnetic film can be made thinner. Therefore, the read gap length can be reduced, and a magnetic head corresponding to a higher recording density of a magnetic recording medium can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a spin valve film manufactured by applying the present invention.

FIG. 2 is a schematic configuration diagram showing an ultra-high vacuum sputtering apparatus for forming the spin valve film.

FIG. 3 is a graph showing a relationship between an external magnetic field change and a resistance change rate of a spin valve film manufactured by changing a heat treatment temperature of an antiferromagnetic film.

FIG. 4 is a graph showing the relationship between a change in external magnetic field and a rate of change in resistance of a spin valve film manufactured by changing the heat treatment time of an antiferromagnetic film.

FIG. 5 is a graph showing the relationship between the heat treatment temperature for an antiferromagnetic film in a spin valve film and the thickness of the antiferromagnetic film.

FIG. 6 is a main part side view showing an MR head manufactured by applying the present invention.

FIG. 7 is a view for explaining the method for manufacturing the MR head according to the present invention, and is a cross-sectional view of a principal part showing a substrate material.

FIG. 8 is a diagram for explaining the same method, and is a cross-sectional view of a main part showing a substrate material on which a first nonmagnetic film is formed.

FIG. 9 is a diagram for explaining the same method, and is a cross-sectional view of a principal part showing a substrate material on which a first magnetic film is formed.

FIG. 10 is a diagram for explaining the same method, and is a cross-sectional view of a principal part showing a substrate material on which a second nonmagnetic film is formed.

FIG. 11 is a diagram illustrating the same method, and is a cross-sectional view of a main part showing a state where a second non-magnetic film is polished;

FIG. 12 is a diagram for explaining the same method, and is a cross-sectional view of a principal part showing a substrate material on which a third nonmagnetic film is formed.

FIG. 13 is a view for explaining the same method, and is a cross-sectional view of a main part showing a state where members constituting the MR head are formed.

FIG. 14 is a diagram schematically illustrating a configuration example of an MR head.

[Explanation of symbols]

1 spin valve film, 3rd magnetic film (free layer),
4 Non-magnetic film, 5 Second magnetic film (pin layer), 6 Antiferromagnetic film, 20 MR head, 23 Lower magnetic shield layer, 24 Second non-magnetic layer, 25 Third non-magnetic layer, 2
6 magnetoresistive element (MR element), 28 fourth nonmagnetic layer, 29 intermediate magnetic shield layer

Claims (2)

[Claims] 1. A method for manufacturing a spin valve film comprising a first magnetic film, a non-magnetic film, a second magnetic film, and an antiferromagnetic film formed of a Pt—Mn alloy. In the graph in which the horizontal axis represents the heat treatment temperature for the antiferromagnetic film and the vertical axis represents the thickness of the antiferromagnetic film, the point A (2
80 ° C., 15 nm), point B (310 ° C., 15 nm), point C (280 ° C., 30 nm), point D (250 ° C., 30 n)
m) performing a heat treatment on the antiferromagnetic film in a range surrounded by the four points of m). 2. A magnetic sensing element for detecting a magnetic signal from a magnetic recording medium, comprising: a first magnetic film, a non-magnetic film, a second magnetic film, and an antiferromagnetic material formed of a Pt—Mn alloy. A method for manufacturing a magnetoresistive magnetic head including a spin valve film formed by laminating films, wherein a horizontal axis indicates a heat treatment temperature for the antiferromagnetic film, and a vertical axis indicates a film thickness of the antiferromagnetic film. In the graph, the point A (2
80 ° C., 15 nm), point B (310 ° C., 15 nm), point C (280 ° C., 30 nm), point D (250 ° C., 30 n)
m) heat-treating the antiferromagnetic film in a range surrounded by the four points of m).