JP2001034917A - Magnetoresistive effect type head and magnetic recorder /reproducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deal with narrow gap or narrow track by applying an electrode forming method employing reactive etching in which thinning of an Mn based alloy antiferromagnetic film and electrode interval can be controlled with high accuracy. SOLUTION: A magnetoresistive effect film comprises a free layer ferromagnetic film 11, a nonmagnetic film 12, a fixed layer ferromagnetic film 13, and an Mn based alloy antiferromagnetic film 14 formed sequentially on a substrate 10 wherein a protective film 15 is formed on the antiferromagnetic film 14 in order to accelerate regularization of the antiferromagnetic film 14. The antiferromagnetic film 14 is heat treated for regularization after the protective film 15 is formed thereon. Furthermore, resistance against reactive ion etching of SF6, or the like, is imparted by adding Cr or a novel metal into the protective film 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-resistance effect type magnetic head for reproducing magnetically recorded information, and a magnetic recording / reproducing system mounted with the magneto-resistance effect type magnetic head for reading / writing information magnetically. It concerns the device.

[0002]

2. Description of the Related Art As magnetic recording / reproducing apparatuses have become smaller and larger in capacity, higher recording density has been required. In order to realize this, the magnetic head mounted on the magnetic recording / reproducing apparatus has been changed from an inductive head which performs both recording and reproduction to a recording / reproducing separation type head which performs recording with an inductive head and reproducing with a magnetoresistive (MR) head. Has been migrated to. Since the reproduction characteristics of the MR head do not depend on the relative speed between the recording medium and the head, high-sensitivity reproduction characteristics can be obtained even if the diameter of the recording medium is reduced. In this MR head, the anisotropic magnetoresistance (AMR) effect is used.
The AMR effect is a phenomenon in which the electric resistance of a ferromagnetic film changes according to the relative angle between the direction of current flowing in the ferromagnetic film and the magnetization direction of the ferromagnetic film. The electric resistance of the ferromagnetic film is minimum when the current direction and the magnetization direction are orthogonal, and becomes maximum when they are parallel. The resistance change rate defined by the amount of resistance change (maximum resistance-minimum resistance) / minimum resistance is 2 to 5% by the AMR effect.
It is known that values of the order can be obtained. In an MR head utilizing the AMR effect, there is a concern that sensitivity may be insufficient at a high recording density of about several Gb / in ² .

A GMR head utilizing a giant magnetoresistive (GMR) effect has attracted attention as a candidate for a reproducing head for realizing a high recording density of several Gb / in ^{2 or} more, and research and development have been actively conducted. The GMR effect is a phenomenon in a multilayer film in which a ferromagnetic film and a non-magnetic film are alternately stacked, in which electric resistance changes according to the relative angle of magnetization of the ferromagnetic film separated by the non-magnetic film. The resistance is minimum when the magnetization directions of the ferromagnetic films are parallel, and maximum when the magnetization directions are antiparallel.
The rate of change in resistance of the GMR film is smaller than that of the AMR film.
It is very large and is expected to be able to dramatically improve the performance as a magnetic sensor and a head. JP-A-2-61572 discloses a magnetic sensor using an antiferromagnetically coupled multilayer film in which ferromagnetic films and nonmagnetic films are alternately stacked. The multilayer film shown in this disclosure example is:
When there is no external magnetic field, the ferromagnetic films separated by the non-magnetic film are antiferromagnetically coupled, and the magnetization is antiparallel arranged. When an external magnetic field is applied to the multilayer film, the magnetization changes from the anti-parallel arrangement to the parallel arrangement, and in this process, the electric resistance of the multilayer film changes. Therefore, the electrode, power supply,
If the output signal detecting means is attached, it operates as a magnetic sensor that outputs a magnetic signal as a change in voltage or current.

The most promising GMR film from the viewpoint of application to a magnetic head for detecting a weak magnetic signal is a spin valve film described in Japanese Patent Application Laid-Open No. 4-358310. The basic structure of the spin valve film is a ferromagnetic film / non-magnetic film / ferromagnetic film / antiferromagnetic film. A ferromagnetic film whose magnetization direction is fixed in one direction by exchange coupling with an antiferromagnetic film is called a fixed layer, and the other ferromagnetic film freely changes its magnetization direction in response to an external magnetic field. Because it can be changed, it is called a free layer. The spin-valve GMR sensor and the head output a magnetic signal as a voltage change or a current change by utilizing a phenomenon that electric resistance changes according to an angle between magnetization of a fixed layer and a free layer.

In the magnetic recording / reproducing apparatus, in order to improve the recording density, it is necessary to reduce each recording / reproducing area of the recording medium, that is, the recording bit length and the track width. At this time, as the reproducing head, for the former, the gap length defined by the upper and lower shield intervals sandwiching the spin valve film with the insulating film interposed therebetween is reduced, and for the latter, the reproducing track width, that is, the spin valve film, It is required to reduce the patterning dimension and electrode spacing.

The narrowing of the gap is realized by thinning the insulating film and the spin valve film. However, there is a limit to reducing the thickness of the insulating film from the viewpoint of dielectric strength. Therefore, in order to cope with the narrowing of the gap, it is necessary to reduce the thickness of the spin valve film. Generally, the antiferromagnetic film is the thickest of the films constituting the spin valve film. In addition, the range in which the thicknesses of the free layer ferromagnetic film, the non-magnetic film, and the fixed layer ferromagnetic film can be reduced is extremely limited from the viewpoint of ensuring the reproduction sensitivity. For the above reasons, for narrowing the gap, making the antiferromagnetic film thinner is an important technical issue.

In a broad sense, the reproduction track width is determined by the distance between a pair of electrodes electrically connected to a spin valve film patterned corresponding to a fine recording / reproduction area.
An example of this reproduction track forming method is disclosed in JP-A-3-12.
The method described in No. 5311 is known. This method uses a lift-off pattern formed to a desired size as a mask, cuts off both ends of the magnetoresistive film by ion milling or the like, forms an electrode film, and removes the lift-off pattern mask and unnecessary electrode films. This is a method of forming an electrode having a predetermined shape by using the above method. Another example is disclosed in
There is a method described in US Pat. In this method, an electrode film is formed directly on the entire surface of the magnetoresistive film,
In this method, after a photoresist mask is formed in a desired electrode shape, an extra electrode film formed on a region corresponding to the track width of the spin valve film is removed by a reactive ion etching method using CF ₄ gas. It is expected that it will be very difficult to form a good lift-off pattern as the electrode spacing becomes smaller. Therefore, it is considered that the use of the reactive ion etching method is more advantageous for achieving a narrow track width dimension on the order of submicrons. However, in this method, when the electrode film is over-etched, the outermost surface of the magnetoresistive film may be damaged. In particular, when the free layer ferromagnetic film is disposed on the outermost surface of the spin valve film, or when the antiferromagnetic film is disposed on the outermost surface and the film thickness is small, damage caused by over-etching is caused. It is feared that the reproduction characteristics are degraded by this.

[0008]

As described above, it is important to reduce the thickness of the spin valve, especially the thinning of the antiferromagnetic film, in response to the reduction of the recording bit length accompanying the improvement of the recording density. It is. In general, when the antiferromagnetic film is thinned, the exchange coupling characteristic for fixing the magnetization direction of the fixed layer and the thermal stability thereof are often insufficient, and in this case, a reproducing head exhibiting good reproducing characteristics cannot be obtained.

Further, in order to form an electrode using a reactive ion etching method and to realize a narrow track width, it is important that the spin valve film has a resistance to the reactive ion etching. That is, when the electrode is formed by the reactive ion etching method, the outermost surface of the spin valve film is exposed to the atmosphere of the reactive ion etching, so that the electrical and magnetic characteristics of the spin valve film are impaired. Is a significant loss in the reproducing characteristics of the head and its manufacture.

Accordingly, an object of the present invention is to form an antiferromagnetic film with a thin film to cope with a narrow gap, and to form an electrode using reactive ion etching which can control the electrode interval for determining the reproduction track width with high precision. It is an object of the present invention to provide a spin valve film configuration to which the method can be applied and a method of manufacturing the same, and a magnetoresistive effect type magnetic head and a magnetic recording / reproducing apparatus which realize a recording density of several Gb / in ^{2 or} more.

[0011]

According to the present invention, a free layer ferromagnetic film / nonmagnetic film is provided in order from the substrate side as means for narrowing the gap of a magnetoresistive head mounted on a magnetic recording / reproducing apparatus. / Fixed layer ferromagnetic film / a spin valve film formed by laminating Mn-based alloy antiferromagnetic films requiring ordered heat treatment, or first antiferromagnetic film / first fixed layer ferromagnetic film /
First nonmagnetic film / free layer ferromagnetic film / second nonmagnetic film / second
It is assumed that a dual spin valve film formed by laminating a fixed layer ferromagnetic film / a second antiferromagnetic film made of a Mn-based alloy requiring ordered heat treatment is used for a reproducing head.
The reason for selecting a Mn-based alloy that requires ordered heat treatment as the antiferromagnetic film disposed on the outermost surface of the film is that the exchange coupling magnetic field applied to the fixed-layer ferromagnetic film is large and the so-called blocking temperature (exchange (Defined as the temperature at which the coupling magnetic field disappears) and is excellent in thermal stability. For example, when the Mn-based alloy is, for example, a MnPt alloy, it has a face-centered cubic structure immediately after film formation, does not exhibit antiferromagnetism, does not apply an exchange coupling magnetic field to the fixed-layer ferromagnetic film, and has at least one heat treatment. The part changes to a face-centered tetragonal structure in which Mn and Pt atoms are regularly arranged, exhibits antiferromagnetism, and gives an exchange coupling magnetic field to the fixed-layer ferromagnetic film. The exchange coupling characteristics deteriorate as the film thickness of Pb decreases. One of the reasons is that Mn atoms and P
It is generally known that it is difficult to realize a structural change to a face-centered tetragonal crystal in which t atoms are regularly arranged.

The means for reducing the thickness of the Mn-based alloy antiferromagnetic film in the present invention is to promote a structural change from face-centered cubic to face-centered tetragonal crystal having antiferromagnetism. Hereinafter, the means will be described in detail. As the Mn-based alloy antiferromagnetic film requiring the above-described ordered heat treatment, 0 <x ≦ 0.
Ni, Ru, Rh, Pd, Ag, Re, Os, I in a Cr _x Mn _1-x alloy or Mn simple substance having a composition range of 5
It is preferable to use an alloy containing at least one of r, Pt, and Au at 40 to 60 at%. Usually this M
Immediately after film formation, the n-based alloy film has a face-centered cubic structure in which Mn atoms (which may partially include Cr atoms) and the above-described additive atoms are arranged irregularly. Does not exhibit ferromagnetism. This is heat-treated at a temperature of about 200 to 350 ° C., so that at least a part thereof has a regular arrangement of Mn atoms (sometimes substituted by Cr atoms) and additive atoms. It has a tetragonal structure and exhibits antiferromagnetism. At this time, as the heat treatment temperature is higher, the structural change to the face-centered tetragonal structure is apt to progress, but at the same time, the GMR characteristic of the spin valve film is deteriorated, and the read sensitivity of the magnetic head is reduced. Therefore, it is necessary to cause a structural change by heat treatment at a relatively low temperature without deteriorating GMR characteristics. In particular, when the thickness of the Mn-based alloy film is as thin as about 20 nm or less, the above-described structural change tends to hardly occur. Then, a protective film for the purpose of promoting the ordering of the antiferromagnetic film is laminated on the Mn-based alloy antiferromagnetic film disposed on the film surface side, and after laminating the protective film, The thinning of the Mn-based alloy antiferromagnetic film can be achieved by performing the ordered heat treatment of the antiferromagnetic film. The material used for this protective film is T
i, V, Cr, Zr, Nb, Mo, Ru, Rh, Pd,
Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au
It is effective if it is a simple substance or an alloy mainly containing at least one of them.

By the above means, even when the thickness of the Mn-based alloy film is as thin as about 20 nm or less, a regular arrangement of face-centered tetragonal crystals exhibiting antiferromagnetism by a relatively low-temperature heat treatment at about 270 ° C. With this structure, a sufficiently large exchange coupling magnetic field can be applied to the fixed-layer ferromagnetic film. as a result,
When the thickness of the Mn-based alloy antiferromagnetic film is 30 nm or less,
nm or less, and it is possible to cope with the narrowing of the reproducing head gap as the recording density increases.

The film thickness of the above-mentioned protective film is sufficiently effective when it is about several nm, and is preferably 5 nm or less in consideration of a decrease in reproduction output due to a shunt loss. Further, it is more preferable that the protective film has an element, an alloy composition, and a structure in which the electric resistivity is at least 20 μΩ-cm or more. This not only has the effect of reducing the shunt loss of the spin valve film, but also corresponds to the protective film having a high electrical resistivity, that is, the high mechanical strength of the protective film. This is because the protection effect of the antiferromagnetic film disposed on the outermost surface side can be maintained at a higher temperature for a longer time. In general, as a method of increasing the electrical resistivity of a metal or a metal film and increasing the mechanical strength, the effect of solid solution of two or more different metals is widely known. Particularly, when metals having different atomic radii form a solid solution, the electrical resistivity and the mechanical strength increase and improve. Therefore, Ti, V,
Cr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, H
When a protective film containing at least one of f, Ta, W, Re, Os, Ir, Pt, and Au and containing at least two kinds of constituent elements is used, a thin film of a Mn-based alloy antiferromagnetic film can be obtained. As a result, the effect of improving the reproduction output and the mechanical strength can be obtained. In particular, alloying with the addition of Cr has the effect of increasing magnetic electron scattering and reducing the crystal grain size, and increasing the electrical resistivity is known in many alloy systems. Ti,
V, Mn, Fe, Co, Ni, Cu, Zr, Nb, M
o, Ru, Rh, Pd, Ag, Hf, Ta, W, Re,
It is made of an alloy of at least one of Os, Ir, Pt, and Au with Cr, and has a Cr composition of 1 to 89a.
When a material having t% is used, the above-described effect is further enhanced.

Further, in order to form an electrode by using a reactive ion etching method and to realize a narrow track width, it is possible to solve the problem by imparting resistance to the reactive ion etching to the spin valve film. That is, the chemically stable elements Cr, Ru, Rh, Pd, Ag, Re, Os, I
r, Pt, Au alone, or an alloy containing at least one of them as a main component may be formed as a protective film of the spin valve film. This makes it possible to provide strong resistance to various gases and plasmas used for reactive ion etching. Therefore, it is possible to prevent damage to the spin valve film during reactive ion etching, and to form electrodes by controlling the electrode spacing with high precision using reactive ion etching without deteriorating the reproduction characteristics. As a result, narrow tracks can be formed. As described above, the thickness of the protective film is set to 5 to minimize the decrease in the reproduction output due to the shunt loss of the protective film.
nm or less, and the electrical resistivity of the protective film is at least 20
The element, alloy composition, and structure should be at least μΩ-cm. Therefore, Cr, Ru, Rh, Pd, Ag, R
The use of a protective film containing at least one of e, Os, Ir, Pt, and Au and comprising at least two or more alloying elements not only provides resistance to reactive ion etching, but also improves reproduction output. The effect of improving the mechanical strength can be obtained. Further, Ti, V,
Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, R
u, Rh, Pd, Ag, Hf, Ta, W, Re, Os,
At least one of Ir, Pt, and Au;
When a material made of an alloy with r and having a Cr composition of 1 to 89 at% is used, the above-described effect is further enhanced.

A magnetic head composed of a reproducing head and a recording head using a spin valve film in which an antiferromagnetic film is made thinner and an electrode corresponding to a narrow track width is formed by using the above means, and information is recorded. A magnetic recording / reproducing apparatus having a magnetic recording medium, actuator means for moving a magnetic head to a predetermined position on the magnetic recording medium, and control means for controlling transmission / reception of information written or read by the magnetic head and movement of the actuator means , High recording density can be realized.

[0017]

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

FIG. 1 shows a configuration of a spin valve film according to an embodiment of the present invention. A free layer ferromagnetic film 11 on a substrate 10
In this configuration, a nonmagnetic film 12, a fixed-layer ferromagnetic film 13, a Mn-based alloy antiferromagnetic film 14 requiring an ordered heat treatment, and a protective film 15 are sequentially stacked. A base film may be inserted between the substrate 10 and the free layer ferromagnetic film 11. The free layer ferromagnetic film 1
1 may be composed of a single type of material or a configuration in which a plurality of different materials are stacked. As an example of the spin valve film configuration, glass / Ta (5) / NiFe (3) /
CoFe (0.5) / Cu (2.1) / CoFe (2) / MnP
t (12) / Ta (3). The values in parentheses indicate the film thickness.
The unit is nm. The composition of each alloy film is Ni ₈₁ Fe ₁₉ ,
Co ₉₀ Fe ₁₀ and Mn ₄₈ Pt ₅₂ . Ta (5) is a base film, NiFe (3) / CoFe (1) is a free layer ferromagnetic film 11
Respectively. The spin valve film according to the present invention is formed by using a DC magnetron sputtering apparatus to form an Ar film.
It was produced in an atmosphere. The thickness of each film was measured by measuring the film forming speed in advance and controlling the opening and closing timing of a shutter provided between the target and the substrate. In addition, it is possible to apply a DC magnetic field of about 100 Oe at the center of the substrate in the plane of the substrate by a pair of permanent magnets installed at both ends of the substrate, thereby inducing a uniaxial anisotropy in the ferromagnetic film. . The substrate can be rotated in the chamber, and the direction in which the uniaxial anisotropy is induced can be set arbitrarily. Uniaxial anisotropy was induced in the free layer ferromagnetic film 11 in the direction 101 shown in FIG. The ordered heat treatment of the Mn-based alloy antiferromagnetic film 14 was performed at 270 ° C. for 3 hours in a vacuum. At this time, the Mn-based alloy antiferromagnetic film 14
The one-way anisotropy caused by exchange coupling with is shown in FIG.
A magnetic field of 3 kOe was applied so as to give a direction of 02.

FIG. 2 shows the magnetoresistance effect curves of the spin valve films according to the present invention and the prior art. The structure of the spin valve film is glass / Ta (5) / NiFe (4) / CoFe
(0.5) / Cu (2.1) / CoFe (2) / MnPt (12)
[/ Ta (3)], and the sample of the present invention used T /
While a (3) is laminated, the sample of the prior art does not have a protective film. In order to cope with the narrowing of the gap, it is advantageous not to laminate the protective film because the total thickness of the spin valve film becomes thin. However, as is apparent from FIG. 2, the spin valve film of the present invention in which Ta (3) is laminated as a protective film has a larger exchange coupling magnetic field Hua and a smaller coercive force Hcp of the fixed layer ferromagnetic film. This is Ta (3)
It is presumed that, as a result, the ordering of the MnPt antiferromagnetic film was facilitated during the heat treatment.
Ti, V, Cr, Zr, Nb, Mo, R
u, Rh, Pd, Ag, Hf, Ta, W, Re, Os,
Ir, Pt, Au alone, or at least one of them
It was also confirmed that the exchange coupling characteristics were similarly improved when an alloy containing at least one kind was used as a main component. On the other hand, when Cu, NiFe, CoFe or the like is used as the protective film, as will be described in detail later, almost no improvement in the exchange coupling characteristic is recognized as compared with the case where the protective film is not laminated. This suggests that the reason why the exchange coupling characteristic is deteriorated when the protective film is not stacked is not that the surface of the antiferromagnetic film is oxidized.

The stability of the magnetization direction of the pinned ferromagnetic film with respect to an external magnetic field was examined for the two spin valve films whose magnetoresistive effect curves are shown in FIG. After applying a magnetic field in the direction opposite to the unidirectional anisotropy imparted to the fixed-layer ferromagnetic film, ± 20
The magnetoresistance effect was measured in the range of Oe. FIG. 3 shows the results. The horizontal axis in FIG. 3 is the magnitude of the external magnetic field applied in the direction opposite to the unidirectional anisotropy imparted to the fixed-layer ferromagnetic film, and the vertical axis is the rate of resistance change ΔR in the minor loop of the magnetoresistance effect curve measured thereafter. / R is the maximum value. In the case where the protective film of the prior art is not provided, the rate of change in resistance sharply decreases from the vicinity where the external magnetic field exceeds 300 Oe. On the other hand, when Ta (3) of the present invention is laminated as a protective film, the resistance change rate does not decrease to near 1 kOe. That is, in the prior art, there is a concern that the reproduction output is reduced due to the signal magnetic field from the magnetic recording medium, the recording magnetic field generated from the recording head, and the like, but this can be avoided by using the means of the present invention. Becomes This is due to the effect that the magnetization direction of the fixed-layer ferromagnetic film is more firmly fixed in one direction by the means of the present invention.

FIG. 4 shows an exchange coupling magnetic field Hua and a resistance change ΔR in a spin valve film using the means of the present invention.
Shows the dependence of MnPt on the antiferromagnetic film thickness. The structure of the spin valve film is glass / Ta (5) / NiFe (3) / CoFe
(1) / Cu (2.1) / CoFe (2) / MnPt (t) / Ta
(3). MnPt film thickness is about 200 Oe at 9 nm,
A sufficiently large exchange coupling magnetic field of 500 Oe or more is obtained at 12 nm or more. Further, MnP can be obtained by means of the present invention.
As a result of reducing the thickness of the t antiferromagnetic film, the shunt loss in the antiferromagnetic film could be reduced. As a result, the resistance change was 1.7 Ω / □ or more when the MnPt film thickness was 12 nm. I have.

FIG. 5 shows the relationship between temperature and exchange coupling magnetic field Hua in a spin valve film using the means of the present invention. The measured sample is part of the result shown in FIG. The blocking temperature is 350 ° C. or higher for both MnPt film thicknesses of 9 nm and 15 nm. That is, MnP
Even when the thickness t is reduced, the thermal stability is sufficiently high.

FIG. 6 shows the relationship between the electrical resistivity of the protective film and the exchange coupling magnetic field Hua of the spin valve film. The structure of the spin valve film is glass / Ta (5) / NiFe (3) /
CoFe (0.5) / Cu (2.1) / CoFe (2) /
MnPt (12, 15) / protective film (3). As the protective film, Cu, CoFe, NiFe, RuCrNi
PtCr and Ta were used. For comparison, a spin valve film without a protective film was also prepared, and the electrical resistivity of the protective film was plotted as 0. The electric resistivity of the protective film is 200 nm
A single-layered film having a degree of protection was prepared, and its sheet resistance was measured and calculated. The electrical resistivity of the protective film is C
u: 3, CoFe: 16, NiFe: 25, RuCr:
48, NiPtCr: 80, Ta: 180 μΩ-cm. From the figure, the electric resistivity of the protective film is 20μΩ-cm.
In the spin valve films described below, the exchange coupling magnetic field is as small as 250 Oe or less, whereas when the exchange coupling magnetic field is larger than 20 μΩ-cm, the exchange coupling magnetic field increases to about 400 Oe, and it is apparent that the exchange coupling magnetic field is clearly improved. This is probably because the application of a material having a high electrical resistivity to the protective film corresponds to the application of a protective film having a high mechanical strength. That is, a material having a high electric resistivity is generally a material having a high melting point, a small crystal grain size, or a material containing a large amount of defects and dislocations in the crystal, and therefore has a property of excellent mechanical strength. is there.

FIG. 7 shows the relationship between the Cr composition of the NiPtCr protective film and the electrical resistivity. Pt composition is about 20at%
And was fixed. When the Cr composition increases, the electrical resistivity increases, which greatly exceeds 20 μΩ-cm without Cr.
It can be seen that it reaches up to 80 μΩ-cm.

FIG. 8 shows that Ta and NiPtC
4 shows magnetoresistive effect curves of a spin valve film laminated with r before and after reactive ion etching using SF ₆ gas.
The etching was performed using a helicon type plasma etching apparatus. When the protective film is Ta, the exchange coupling magnetic field is significantly reduced after exposure to the reactive ion etching, indicating that the protective film does not function as a magnetoresistive film. On the other hand, when the NiPtCr film is used, the magnetoresistance curve shows a sufficiently large exchange coupling magnetic field and a rate of change in resistance even after exposure to reactive ion etching.
It can be seen that the film has good resistance to reactive ion etching.

FIG. 9 shows the thickness of the Ta and NiPtCr protective films and the exchange coupling magnetic field of the spin valve film after the reactive ion etching exposure. When Ta was used as the protective film, the exchange coupling magnetic field after the reactive ion etching exposure was zero as described above. On the other hand, when the NiPtCr protective film was used, a good exchange-coupling magnetic field was obtained even after exposure to reactive ion etching for the samples in all ranges of thickness from 1 nm to 5 nm, indicating that the sample was excellent as a protective film. .

FIG. 10 shows that the Cr contained in the protective film material
The composition and the exchange coupling magnetic field of the spin valve film after the exposure were set to 1 before the reactive ion etching exposure. It can be seen that as the Cr composition increases, the resistance to reactive ion etching improves. Pure Cr film has an electrical resistivity of 16
Since the resistance is as low as μΩ-cm, the magnitude of the exchange coupling magnetic field itself can be improved by appropriately adding an additive to increase the electric resistivity.

FIG. 11 shows the structure of a spin valve film according to another embodiment of the present invention. On a substrate 20, a first antiferromagnetic film 21 / first fixed layer ferromagnetic film 22 / first nonmagnetic film 23
/ Free layer ferromagnetic film 24 / second nonmagnetic film 25 / second fixed layer ferromagnetic film 26 / second antiferromagnetic film 27 made of a Mn-based alloy requiring ordered heat treatment / protective film 28 Are sequentially laminated. A base film may be inserted between the substrate 20 and the first antiferromagnetic film 21. In addition, the free layer ferromagnetic film 24
May be composed of one type of material, or may be composed of a plurality of different materials. In the free layer ferromagnetic film 24, uniaxial anisotropy was induced in the 202 direction shown in FIG. 11 by a magnetic field applied during film formation. The first fixed layer ferromagnetic film 22 and the second fixed layer ferromagnetic film 26 have the first
The unidirectional anisotropy resulting from exchange coupling between the antiferromagnetic film 21 and the second antiferromagnetic film 27 made of a Mn-based alloy was given to the directions 201 and 202 shown in FIG. This unidirectional anisotropy was induced by an applied magnetic field during film formation and heat treatment. Although the details are omitted, even in the case of this film configuration, the thickness of the second antiferromagnetic film 27 can be reduced by using the above-described means.

FIG. 12 schematically shows a sectional structure of a magnetoresistive head according to an embodiment of the present invention. After forming the insulating film 31, the lower shield film 32, and the lower gap film 33 on the substrate 30, the spin valve film 1 or 2 having the structure shown in FIG. 1 or 6 is laminated.
After patterning the spin valve film into a predetermined shape, a magnetic domain control film 37 is formed on both ends thereof for the purpose of suppressing Barkhausen noise. Further, a pair of electrodes 38 for detecting a change in electric resistance of the spin valve film is formed, and an upper gap film 34 and an upper shield film 35 are sequentially formed. Further, after forming the insulating film 36, an inductive magnetic head for recording is manufactured, but the details are omitted.

At present, a pair of electrodes 38 for detecting a change in electric resistance of a spin valve film is generally formed by a lift-off process. However, when the recording density is improved and the track width is narrowed, it may be difficult to form electrodes by this method. As an alternative technique to the lift-off process, a method has been proposed in which an electrode film is formed on the entire surface of a spin valve film, and then the electrode film of the sense portion is removed by RIE. In this case, it is necessary to suppress damage to the spin valve film caused by over-etching. In order to avoid this damage, Cr, Ru, Rh, P
It is preferable to use a single noble metal such as d, Ag, Re, Os, Ir, Pt, and Au, or an alloy containing at least one or more of these as a main component. This material has a sufficiently low etching rate to minimize RIE damage. As a gas species for the reactive ion etching, for example, SF ₆ can be used.

FIG. 13 shows a schematic structure of an embodiment of a magnetic disk drive equipped with a magnetoresistive head according to the present invention. The magnetic disk drive includes a spindle 40 and a magnetic recording medium 41 installed around the spindle 40.
, A motor 42 for driving the spindle 40, a movable carriage 43, a magnetic head 44 held by the carriage 43, a voice coil motor 45 for driving the carriage 43, and a base 46 for supporting the same. You. In FIG. 13, one magnetic recording medium 41 and one magnetic head 44 are shown for the sake of simplicity, but a plurality of these may be used. Furthermore,
The magnetic recording medium 41 may be one capable of recording on both sides. In this case, the magnetic heads 44 are arranged on both sides of the magnetic recording medium 41. As a control system, according to a signal transmitted from a higher-level device 47 such as a magnetic disk controller,
A voice coil motor control circuit 48 for controlling the voice coil motor 45 is provided. Also, the function of converting the data sent from the host device 47 into a current to be passed to the magnetic head 44 in accordance with the writing method of the magnetic recording medium 41, and the function of amplifying the data sent from the magnetic head 44, A write / read circuit 49 having a function of converting into a digital signal is provided.
It is connected to the host device 47 via the interface 50.

Next, the operation of the magnetic disk device for reading data from the magnetic recording medium 41 will be described. The host device 47 gives an instruction of data to be read to the voice coil motor control circuit 48 via the interface 50. Voice coil motor control circuit 4
8, the voice coil motor 45 drives the carriage 43 to move the magnetic head 44 to the position of the track on the magnetic recording medium 41 where the designated data is recorded at a high speed, and accurately position the magnetic head 44. I do. In this positioning, the magnetic head 44 reads the servo information written together with the data on the magnetic recording medium 41, and
This is performed by providing a signal regarding the position to the voice coil motor control circuit 48. The motor 42 supported by the base 46 rotates the magnetic recording medium 41 attached to the spindle 40. Next, in accordance with a signal from the write / read circuit 49, after detecting the head position of the designated area, the data signal of the magnetic recording medium 41 is read. This reading is performed by transmitting and receiving signals between the magnetic head 44 connected to the write / read circuit 49 and the magnetic recording medium 41. The read data is converted into a predetermined signal and sent to the host device 47.

With the above-described configuration, the magnetoresistive head of the present invention and a magnetic recording / reproducing apparatus equipped with the same were tested. As a result, a reproducing characteristic showing sufficient sensitivity and resolution was obtained, and the operation reliability was improved. Was also good.

Here, the embodiment in which the magnetoresistive head according to the present invention is applied to a magnetic disk drive has been described. However, the magnetoresistive head according to the present invention can be applied to other magnetic disks such as a magnetic tape drive. It is also applicable to a recording / reproducing device.

[0035]

As described above, according to the present invention, even if the thickness of the Mn-based antiferromagnetic film requiring ordering heat treatment is reduced, good exchange coupling characteristics and its thermal stability can be obtained. .
In addition, since a process requiring a chemical selectivity such as reactive ion etching can be applied, electrodes with narrow intervals can be formed. As a result, it is possible to achieve a narrower gap and a narrower track of the reproducing head, and it is possible to obtain a magnetic recording and reproducing apparatus having a high recording density.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a spin valve film according to an embodiment of the present invention.

FIG. 2 is a diagram showing a magnetoresistive effect curve of the spin valve film according to the related art and the present invention.

FIG. 3 is a diagram showing the stability of the rate of change of resistance with respect to an external magnetic field of the spin valve films of the prior art and the present invention.

FIG. 4 is a diagram showing the relationship between the thickness of the Mn-based antiferromagnetic film, the exchange coupling magnetic field, and the amount of resistance change in the spin valve film of the present invention.

FIG. 5 is a diagram showing the relationship between temperature and exchange coupling magnetic field in the spin valve film of the present invention.

FIG. 6 is a diagram showing the relationship between the electrical resistivity of the protective film and the exchange coupling magnetic field of the spin valve film in the spin valve film of the present invention.

FIG. 7 shows NiPtCr in the spin valve film of the present invention.
FIG. 4 is a diagram showing a relationship between a Cr composition of a protective film and an electric resistivity.

FIG. 8 is a diagram showing a magnetoresistance effect curve before and after reactive ion etching exposure when Ta and NiPtCr are used as a protective film in the spin valve film of the present invention.

FIG. 9 shows Ta and Ni in the spin valve film of the present invention.
FIG. 4 is a diagram illustrating a relationship between a thickness of a PtCr protective film and an exchange coupling magnetic field after exposure to reactive ion etching.

FIG. 10 is a diagram showing the relationship between the Cr composition contained in the protective film material and the change in the exchange coupling magnetic field before and after reactive ion etching exposure in the spin valve film of the present invention.

FIG. 11 is a view showing a configuration of a spin valve film according to another embodiment of the present invention.

FIG. 12 is a diagram schematically illustrating a cross-sectional structure of an embodiment of a magnetoresistive head according to the present invention.

FIG. 13 is a diagram showing a schematic structure of an embodiment of a magnetic recording / reproducing apparatus using a magnetoresistive head of the present invention.

[Explanation of symbols]

1, 2,... Spin valve film, 10, 20, 30,.
DESCRIPTION OF SYMBOLS 1 ... Free layer ferromagnetic film, 12 ... Nonmagnetic film, 13 ... Fixed layer ferromagnetic film, 14 ... Mn-based alloy antiferromagnetic film which needs ordering heat treatment, 15 ... Protective film, 101 ... Free layer ferromagnetic Direction of uniaxial anisotropy induced in the film, 102 ... direction of unidirectional anisotropy imparted to the fixed-layer ferromagnetic film, 21 ... first antiferromagnetic film,
22: first fixed layer ferromagnetic film, 23: first nonmagnetic film,
24 free layer ferromagnetic film, 25 second nonmagnetic film, 26
Second fixed-layer ferromagnetic film, 27... Second antiferromagnetic film made of a Mn-based alloy requiring ordered heat treatment, 28... Protective film, 201. Direction of directional anisotropy, 202: direction of uniaxial anisotropy induced in free layer ferromagnetic film, 203: direction of unidirectional anisotropy imparted to second fixed layer ferromagnetic film, 31, 36 ... insulation Film 32 lower shield film 33 lower gap film 34 upper gap film 35 upper shield film 37 magnetic domain control film 38
... a pair of electrodes, 40 ... spindle, 41 ... magnetic recording medium, 42 ... motor, 43 ... carriage, 44 ... magnetic head, 45 ... voice coil motor, 46 ... base, 47 ...
Host device, 48 ... Voice coil motor control circuit, 49 ...
Write / read circuit, 50 ... interface.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Nobuo Yoshida 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. Central Research Laboratory F-term (reference) 5D034 BA05 BA17 BB12 DA07

Claims (17)

[Claims] 1. A free layer ferromagnetic film, a non-magnetic film, a fixed layer ferromagnetic film, and Mn requiring ordered heat treatment
A magnetoresistive film formed by laminating an alloy based antiferromagnetic film,
In a magneto-resistance effect type magnetic head having a pair of electrodes for flowing a signal detection current through the magneto-resistance effect film, an object of the present invention is to promote regularization of the anti-ferromagnetic film on the anti-ferromagnetic film. Ti, V, Cr, Zr, Nb, Mo, R
u, Rh, Pd, Ag, Hf, Ta, W, Re, Os,
Ir, Pt, Au alone, or at least one of them
A protective film made of an alloy mainly composed of more than one kind is laminated,
A magnetoresistance effect type magnetic head, wherein an ordered heat treatment of the antiferromagnetic film is performed after the protection film is laminated. A first antiferromagnetic film, a first fixed layer ferromagnetic film, a first nonmagnetic film, a free layer ferromagnetic film, a second nonmagnetic film, and a second nonmagnetic film. A magnetoresistive film formed by laminating a fixed-layer ferromagnetic film and a second antiferromagnetic film made of a Mn-based alloy requiring ordered heat treatment, and a signal detection current flowing through the magnetoresistive film. In a magneto-resistance effect type magnetic head having a pair of electrodes, Ti, V, and Cr are formed on the second antiferromagnetic film to promote the ordering of the second antiferromagnetic film. , Zr, Nb, Mo, R
u, Rh, Pd, Ag, Hf, Ta, W, Re, Os,
Ir, Pt, Au alone, or at least one of them
A protective film made of an alloy mainly composed of more than one kind is laminated,
A magnetoresistive head according to claim 1, wherein said second antiferromagnetic film is subjected to ordered heat treatment after said protective film is laminated. 3. The Mn-based alloy antiferromagnetic film requiring the ordering heat treatment has a C content of 0 <x ≦ 0.5.
r _x Mn _1-x alloy or Mn alone, Ni, Ru, Rh, P
An alloy containing 40 to 60 at% of at least one of d, Ag, Re, Os, Ir, Pt, and Au, and having at least a part of a face-centered tetragonal structure. 3. The magneto-resistance effect type magnetic head according to 1 or 2. 4. The film thickness of the Mn-based alloy antiferromagnetic film requiring the ordering heat treatment is 30 nm or less, particularly 2 to 15 n.
The magnetoresistance effect type magnetic head according to any one of claims 1 to 3, wherein m is m. 5. The magnetoresistive head according to claim 1, wherein the thickness of the protective film is 5 nm or less. 6. The protective film has an electric resistivity of 20 μΩ-
The magnetoresistive head according to any one of claims 1 to 5, wherein the magnetic head is not less than 1 cm. 7. The method according to claim 1, wherein the protective film is made of Ti, V, Cr, Zr,
Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta,
The magnetic material according to any one of claims 1 to 6, wherein at least one of W, Re, Os, Ir, and Pt is contained, and the constituent elements are made of at least two kinds of alloys. Resistance effect type magnetic head. 8. The method according to claim 1, wherein the protective film is made of Ti, V, Mn, Fe,
Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, P
d, Ag, Hf, Ta, W, Re, Os, Ir, Pt,
The magnetoresistance effect according to any one of claims 1 to 7, comprising an alloy of at least one of Au and Cr with Cr having a composition of 1 to 89 at%. Type magnetic head. 9. A magnetoresistive film formed by laminating a free layer ferromagnetic film, a nonmagnetic film, a fixed layer ferromagnetic film, and an antiferromagnetic film in this order from the substrate side, and detecting a signal on the magnetoresistive film. In a magneto-resistance effect type magnetic head having a pair of electrodes for flowing a current, Cr, Ru, Rh, P
A magnetoresistive magnetic head characterized in that a protective film composed of d, Ag, Re, Os, Ir, Pt, Au alone or an alloy containing at least one of them as a main component is laminated. 10. A magnetoresistive film formed by laminating an antiferromagnetic film, a fixed-layer ferromagnetic film, a nonmagnetic film, and a free-layer ferromagnetic film in this order from the substrate side, and detecting a signal on the magnetoresistive film. In a magneto-resistance effect type magnetic head having a pair of electrodes for flowing a current, Cr, Ru, R
h, Pd, Ag, Re, Os, Ir, Pt, Au alone,
Alternatively, a magneto-resistance effect type magnetic head characterized by laminating a protective film made of an alloy containing at least one of them as a main component. 11. A first antiferromagnetic film, in order from the substrate side,
A first fixed layer ferromagnetic film, a first nonmagnetic film, a free layer ferromagnetic film, a second nonmagnetic film, a second fixed layer ferromagnetic film, a second antiferromagnetic film, And a pair of electrodes for passing a signal detection current through the magnetoresistive film, a Cr, Ru, Rh film is formed on the second antiferromagnetic film. , Pd, Ag, Re, O
A magnetoresistive head comprising a protective film made of s, Ir, Pt, Au alone or an alloy containing at least one of them as a main component. 12. The method according to claim 9, wherein the thickness of the protective film is 5 nm or less.
Item 7. The magneto-resistive effect type magnetic head according to item 1. 13. An electric resistivity of the protective film is 20 μΩ.
The magnetoresistive head according to claim 9, wherein the magnetic head is −cm or more. 14. The method according to claim 14, wherein the protective film is made of Cr, Ru, Rh, P
14. The semiconductor device according to claim 9, wherein at least one of d, Ag, Re, Os, Ir, Pt, and Au is included, and the constituent elements are at least two or more alloys. 15. The magnetoresistive effect type magnetic head as described in the above. 15. The method according to claim 15, wherein the protective film is made of Ti, V, Mn, F.
e, Co, Ni, Cu, Zr, Nb, Mo, Ru, R
h, Pd, Ag, Hf, Ta, W, Re, Os, Ir,
The magnetic material according to any one of claims 9 to 14, wherein the magnetic material comprises an alloy of at least one of Pt and Au with Cr, and the composition of the Cr is 1 to 89 at%. Resistance effect type magnetic head. 16. The method according to claim 9, further comprising a step of processing a pair of electrodes for flowing a signal detection current through the magnetoresistive film into a predetermined shape by a reactive ion etching method. 9. The method for manufacturing a magnetoresistive head according to claim 1. 17. A magnetic head comprising a magnetic recording medium for recording information, a recording head for writing information on the magnetic recording medium, and a reproducing head for reading information recorded on the magnetic recording medium; A magnetic recording / reproducing apparatus, comprising: actuator means for moving to a predetermined position on a recording medium; and control means for controlling transmission / reception of information written or read by the magnetic head and movement of the actuator means. 16. A magnetic recording / reproducing apparatus comprising the magneto-resistance effect type magnetic head according to any one of 1 to 15.