JPH10163545A - Magnetoresistive effect element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetoresistive effect element and manufacture thereof, whereby a current flows in the thickness direction of a magnetoresistive effect film produced, without causing the electric short-circuit at the sides of the magnetoresistance effect film, and magnetic field detecting region of the magnetoresistive effect film is reduced. SOLUTION: A magnetoresistive effect element has a magnetoresistive effect film 10 on a lower electrode 2. The film 10 is selectively etched to leave this film 10 on a magnetic field-detecting region D. A current is flowed between an upper electrode layer 8, disposed on the magnetoresistance effect film 10 and lower electrode layer 2 for detecting the magnetic field from the change in its electric resistance. A protective film with respect to etching is provided over at least origins on the lower electrode layer 2 than the detecting region D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element and a method of manufacturing the same, and more particularly to a magnetoresistive element exhibiting giant magnetoresistance (GMR) and a method of manufacturing the same.

[0002]

2. Description of the Related Art A magnetoresistive element (MR element) is an element for measuring a magnetic field strength and its change by detecting a change in the magnetoresistance of a magnetoresistive film caused by application of a magnetic field. A reproducing head (MR head) incorporating such a magnetoresistive element has been studied as a reproducing head for a hard disk drive because it has higher magnetic sensitivity than a conventional inductive head. By increasing the sensitivity of such an MR head, it is possible to improve the areal recording density of a hard disk drive. Therefore, development of a magnetoresistive film having a high MR ratio corresponding to sensitivity has been actively pursued in recent years.

A giant magnetoresistive element (GMR element) is known as an element having a large MR ratio. As such a GMR element, a spin-valve type laminated film having a ferromagnetic layer / nonmagnetic conductive layer / ferromagnetic layer / antiferromagnetic layer as a basic structural unit, and a ferromagnetic layer / nonmagnetic conductive layer / ferromagnetic layer are used. As a basic structural unit, a laminated film of a coercive force difference type in which ferromagnetic layers have mutually different coercive forces, an artificial lattice type laminated film in which a ferromagnetic layer / a nonmagnetic conductive layer is repeatedly laminated many times, and the like are known.

In these laminated films, it is considered that current mainly flows in the nonmagnetic conductive layer, and the state of scattering of electrons at the interface between the nonmagnetic conductive layer and the ferromagnetic layer changes due to a change in magnetic field intensity. It is believed that this changes the electrical resistance. In an MR element using these laminated films, a pair of electrodes are provided to face each other along the film surface direction of the laminated film, and a region between these electrodes is used as a magnetic field detection region. Therefore, the width of the magnetic field detection region is determined by the distance between the electrodes.

[0005]

However, in the field of magnetic recording, it is desired to increase the recording density, and thus it is required to reduce the track width of the magnetic recording. With such a reduction in track width, it has been studied to reduce the magnetic field detection region in the MR element.

[0006] In the laminated film having a giant magnetoresistance as described above, the scattering state of electrons at the interface between the nonmagnetic conductive layer and the ferromagnetic layer contributes to the change in the MR ratio. In the conventional GMR element, since the current flows in the nonmagnetic conductive layer along the film surface direction, it is considered that the influence of the scattering state of electrons in the interface region is not sufficiently reflected in the change in the magnetoresistance.

In view of the above, there is a configuration in which the laminated film is provided only in the magnetic field detection region, the electrode layers are provided above and below the laminated film, and a current flows in a direction substantially perpendicular to the film surface direction of the laminated film. Conceivable. With this configuration, the current flowing through the stacked film is affected by the scattering state of electrons in more interface regions, and it is expected that the MR ratio is improved. In addition, since the magnetic field detection region can be formed by forming the laminated film and the electrode layer in a limited manner, the magnetic field detection region, that is, the track width can be reduced.

As a method of providing the laminated film only in the magnetic field detection region only, a method of etching a region other than the magnetic field detection region using photolithography, for example, and leaving the laminated film only in the magnetic field detection region can be considered. However, there is usually a lower electrode layer below the laminated film, and when such a lower electrode layer is etched by sputtering or the like, the material of the lower electrode layer adheres to a side portion of the laminated film, and the lower electrode layer This causes a problem that an electric short circuit occurs.

An object of the present invention is to provide a magnetoresistive element capable of flowing a current in the thickness direction of the magnetoresistive effect film and capable of being manufactured without causing an electric short circuit on the side of the magnetoresistive effect film. And a method for manufacturing the same.

[0010]

The magnetoresistive element of the present invention is provided so that the magnetoresistive film on the lower electrode layer is selectively etched to leave the magnetoresistive film in the magnetic field detection region. A magnetoresistive element for detecting a change in a magnetic field from a change in its electric resistance by flowing a current between an upper electrode layer and a lower electrode layer provided on the magnetoresistive film; It is characterized in that a protective film for etching is provided on at least a region other than the magnetic field detection region on the layer.

According to the present invention, since the protective film for etching is provided at least in a region other than the magnetic field detection region on the lower electrode layer, the protection film is selectively provided so as to leave the magnetoresistive effect film in the magnetic field detection region. During the etching, the lower electrode layer is etched to prevent the lower electrode layer material from adhering to the side of the magnetoresistive film.

The material for forming the protective film in the present invention is not particularly limited as long as it is hard to be etched as compared with the lower electrode layer.
r, Hf, Pb, Sr, Ti, U, V, Nb, Re, S
Metal materials such as b and Te can be used. These protective films may be formed from an amorphous material.

[0013] The manufacturing method of the present invention is a method of manufacturing a magnetoresistive element in which a magnetoresistive film is provided in a magnetic field detecting region between a lower electrode layer and an upper electrode layer. Forming a film, forming a magnetoresistive film on the protective film, and etching a region of the magnetoresistive film other than the magnetic field detection region until it reaches the inside of the protective film, and forming a magnetoresistive effect on the magnetic field detection region. Patterning so as to leave the film, and in the etching step, the lower electrode layer material is prevented from adhering to the side of the magnetoresistive film by the presence of the protective film.

According to the manufacturing method of the present invention, when the magnetoresistive film is etched, the etching is performed until the film reaches the inside of the protective film provided on the lower electrode layer. Therefore, the lower electrode layer is not etched in the etching step, and the lower electrode layer material can be prevented from adhering to the side of the magnetoresistive film.

As the protective film, the same one as the protective film in the magnetoresistance effect element of the present invention can be used. The upper electrode layer may be formed on the magnetoresistive film before the etching step, and may be patterned so as to have a predetermined shape together with the magnetoresistive film in the etching step, that is, the shape of the magnetic field detection region. After etching the magnetoresistive film, the upper electrode layer may be selectively formed. In such a case, for example, it can be formed by a so-called lift-off method in which a region other than the upper electrode layer is masked and the mask is removed after the upper electrode layer is formed.

The thickness of the protective film in the present invention is not particularly limited as long as the lower electrode layer is not etched in the etching step, but generally a thickness of about 5 to 30 nm is appropriate. is there.

The magnetoresistive film in the present invention is not particularly limited. As described above, the magnetoresistive film may be a ferromagnetic layer such as a spin-valve type laminated film, a coercive force difference type laminated film, or an artificial lattice type laminated film. A magnetoresistive film having a stacked structure of nonmagnetic conductive layers can be used. Furthermore, the present invention can be applied to a ferromagnetic tunnel junction type magnetoresistive film having a laminated structure in which a nonmagnetic insulating layer is sandwiched between a pair of ferromagnetic layers.

[0018]

FIG. 1 is a sectional view showing a magnetoresistive element according to an embodiment of the present invention, and FIG. 2 is a plan view.

In the magnetoresistance effect element shown in FIG.
A spin-valve type laminated film is used as the magnetoresistive film. Referring to FIG. 1, a lower electrode layer 2 is formed on a substrate 1. The material of the substrate 1 is not particularly limited as long as it is a non-magnetic material.
Materials such as C, Al ₂ O ₃ , and glass are used.
As the lower electrode layer 2, a material having low electric resistance is used, for example, a material such as Cu is used. In this embodiment, the lower electrode layer 2 is formed to have a thickness of 100 nm. On the lower electrode layer 2, a protective film 3 is formed. In this embodiment, a Zr layer (film thickness 1) is used as the protective film 3.
0 nm) or a Ta layer (10 nm thick).

In the magnetic field detection region D on the protective film 3, a magnetoresistive film 10 is formed. Magnetoresistance effect film 10
Is formed by laminating a ferromagnetic layer 4, a nonmagnetic conductive layer 5, a ferromagnetic layer 6, and an antiferromagnetic layer 7 in this order. In this embodiment, a NiFe layer (thickness: 10 nm) as the ferromagnetic layer 4 and a Cu layer (thickness: 3 n) as the nonmagnetic conductive layer 5
m), a NiFe layer (5 nm thick) as the ferromagnetic layer 6, and a FeMn layer (20 nm thick) as the antiferromagnetic layer 7. An upper electrode layer 8 is formed on the antiferromagnetic layer 7 which is the uppermost layer of the magnetoresistive film 10. In this embodiment, a Cu layer (film thickness 100 n
m) is formed.

Referring to FIG. 2, lower electrode layer 2 and protective film 3 formed on substrate 1 are formed in a direction along edge 1a in a region in contact with edge 1a of substrate 1. . In the case of the MR head, the end 1a of the substrate 1 is a portion to be a head sliding surface. The upper electrode layer 8 is provided so as to intersect substantially vertically in the magnetic field detection region D at the center of the lower electrode layer 2 and the protective film 3. In this embodiment, the magnetoresistive film 10 under the upper electrode layer 8 is formed to have the same pattern shape as the upper electrode layer 8. An electrode lead layer 11 made of Cu or the like is provided at an end of the upper electrode layer 8.
Is connected. In addition, Cu is also applied to the end of the lower electrode layer 2.
Is connected. A current flows between the upper electrode layer 8 and the lower electrode layer 2, and the upper electrode layer 8
And the lower electrode layer 2 function as an MR element. Since a current flows between the upper electrode layer 8 and the lower electrode layer 2, the current flows in a direction substantially perpendicular to the direction of the film surface of the magnetoresistive film 10.

Since the magnetoresistive film 10 of this embodiment is a spin-valve type laminated film, the magnetization direction of the ferromagnetic layer 6 is pinned by the antiferromagnetic layer 7 and the magnetization direction of the ferromagnetic layer 4 Changes under the influence of an external magnetic field, the scattering state of electrons in the boundary region between the ferromagnetic layer 4 and the nonmagnetic conductive layer 5 is affected. In this embodiment, the magnetoresistive film 10
Since the current flows in the direction of the film thickness, the influence of the change in the scattering state of electrons in the boundary region can be more greatly affected, and a larger MR ratio can be exhibited.

FIG. 3 is a cross-sectional view for explaining the steps of manufacturing the magnetoresistive element of the embodiment shown in FIGS. Referring to FIG. 3, lower electrode layer 2 and protective film 3 are sequentially stacked on substrate 1. These thin films can be formed by, for example, an ion beam sputtering method. Next, as shown in FIG. 2, patterning is performed by a photolithography method so that the lower electrode layer 2 and the insulating film 3 are left only in a predetermined region in contact with the end 1a on the substrate 1.

Next, as shown in FIG. 3, a ferromagnetic layer 4, a nonmagnetic conductive layer 5, a ferromagnetic layer 6, and an antiferromagnetic layer 7 are formed on the entire surface in this order. Further, the upper electrode layer 8 is formed on the entire surface of the antiferromagnetic layer 7. Each of these layers can be formed by, for example, an ion beam sputtering method. Next, as shown in FIG. 3, a resist film 9 is formed in the magnetic field detection region D on the upper electrode layer 8. Using this resist film 9 as a mask, the upper electrode layer 8 and the magnetoresistive film 1
Each layer of 0 is etched by, for example, sputtering. This etching is performed until the etching reaches the inside of the protective film 3. Next, by removing the resist film 9, a structure having a sectional view as shown in FIG. 1 can be obtained.

Next, as shown in FIG. 2, an electrode lead layer 11 connected to the upper electrode layer 8 is formed, and an electrode lead layer 12 connected to the lower electrode layer 2 is formed. These electrode lead layers 11 and 12 can be formed by, for example, a lift-off method in which a region other than the formation region is masked and the mask is removed after formation. Preferably, the protective film 3 is removed from the connection part of the electrode lead layer 12 so as to directly contact the lower electrode layer 2.

As described above, the etching is performed so that the upper electrode layer 8 and the magnetoresistive film 10 are left only in the magnetic field detection region D. This etching is completed when the etching reaches the inside of the protective film 3. Therefore, the lower electrode layer 2 is not etched, and the material of the lower electrode layer does not adhere to the side of the magnetoresistive film 10. Further, since the protective film 3 is made of a material which is hard to be sputtered and has relatively high electric resistance, it is hard to be attached to the side of the magnetoresistive film 10 and even if it is attached, no electrical short circuit occurs. Therefore, the magnetoresistive element according to the present invention can be manufactured without causing an electric short circuit at the side of the magnetoresistive film.

FIG. 4 is a sectional view showing a structure in the case where a magnetic domain control layer 13 such as a bias layer is formed in the embodiment shown in FIG. As shown in FIG. 4, when forming the magnetic domain control layer 13 made of CoPt or the like, it is preferable to provide the magnetic domain control layer 13 on the protective film 3 so as to be in contact with the ferromagnetic layer 4 whose magnetization direction changes. .

FIG. 5 is a sectional view showing a magnetoresistive element of another embodiment according to the present invention. In the embodiment shown in FIG. 5, a coercive force difference type laminated film is formed as the magnetoresistive film 20. The magnetoresistive film 20 is formed of the protective film 3
Are formed by stacking a ferromagnetic layer 14, a nonmagnetic conductive layer 15, and a ferromagnetic layer 16 in this order on
The ferromagnetic layers 14 and 16 have different coercive forces. In this embodiment, a NiFe layer (thickness 10 nm) is formed as the ferromagnetic layer 14, a Cu layer (thickness 3 nm) is formed as the nonmagnetic conductive layer 15, and a Co layer (thickness 5 nm) is formed as the ferromagnetic layer 16.

The embodiment shown in FIG. 5 can be manufactured by a method similar to the manufacturing method described with reference to FIG. FIG. 6 is a cross-sectional view showing a magnetoresistive element of still another embodiment according to the present invention. In the embodiment shown in FIG. 6, an artificial lattice type laminated film is formed as the magnetoresistive film 30. The magnetoresistive film 30 has a ferromagnetic layer 21.
And the nonmagnetic conductive layer 22 are repeatedly laminated at a plurality of cycles. In the present embodiment, a Co layer (film thickness: 2 nm) is formed as the ferromagnetic layer 21 and a Cu layer (film thickness: 2.2 nm) is formed as the nonmagnetic conductive layer 22, which is repeatedly laminated at a cycle of 20 times.

The embodiment shown in FIG. 6 can be manufactured by a method similar to the manufacturing method described with reference to FIG. FIG. 7 is a sectional view showing a magnetoresistive element according to still another embodiment according to the present invention. The magnetoresistive film 40 of the embodiment shown in FIG. 7 is a tunnel junction type magnetoresistive film, and includes a ferromagnetic layer 31, a non-magnetic insulating layer 32, and a ferromagnetic layer 3.
3 are laminated in this order. In this embodiment, a NiFe layer (with a thickness of 10
nm), an Al ₂ O ₃ layer (film thickness 2
nm), and a Co layer (5 nm thick) is used as the ferromagnetic layer 33. The tunnel junction type magnetoresistive film 40 used in this embodiment is originally a magnetoresistive film for detecting a change in magnetoresistance by flowing a current in the film thickness direction. The embodiment shown in FIG. 7 can also be manufactured by a manufacturing method similar to the manufacturing method described with reference to FIG.

In each of the above embodiments, as described with reference to FIG. 2, the upper electrode layer and the magnetoresistive film have the same pattern shape, but the present invention is not limited to this. Absent. For example, before forming the upper electrode layer, a resist film is formed on the magnetic field detection region of the magnetoresistive effect film, and the resist film is etched by sputtering or the like using the resist film as a mask, and the upper electrode layer 8 and the lower electrode layer 2 shown in FIG. Patterning so that the magnetoresistive film remains only in the overlapping region of
Thereafter, the upper electrode layer 8 may be formed on the magnetoresistive film. In this case, the upper electrode layer 8 is selectively formed, for example, a portion other than the formation region is covered with a mask, and the upper electrode layer 8 is formed only in a predetermined region. Thereafter, as shown in FIG. 2, electrode lead layers 11 and 12 connected to the upper electrode layer 8 and the lower electrode layer 2 are formed.

Further, in each of the above embodiments, the Zr layer or the Ta layer has been described as an example of the protective film, but the present invention is not limited to this. In the case of a material layer that enhances the crystallinity of a ferromagnetic layer formed thereon, such as a Ta layer and a Zr layer, the protective film of the present invention also has a function as an underlayer of the magnetoresistive film. I have. Alternatively, a protective film made of a material other than these may be formed, a Zr layer or a Ta layer or the like may be formed thereon as a base layer, and a magnetoresistive film may be formed on the base layer.

Further, a Ta layer (for example, a film thickness of 5 nm) or a Zr layer (for example, a film thickness of 5 nm) is formed on the magnetoresistive film as a protective film for improving corrosion resistance and adhesion.
An upper electrode layer may be formed thereon.

In each of the above embodiments, the protective film is provided under the magnetoresistive film. However, the present invention is not limited to this. The protective film is provided in a region other than the magnetic field detection region. The protective film may not be provided below the magnetoresistive effect film which is the magnetic field detection region. When a protective film is provided below the magnetoresistive film,
In order to reduce the resistance of the magnetoresistive film to the current flowing in the film thickness direction, it is possible to make structural improvements such as making the film thickness smaller than the region other than the magnetic field detection region.

The magnetoresistive element of the present invention is not limited to the material of each layer of the magnetoresistive film described in each of the above embodiments, and other materials can be used widely.

[0036]

According to the present invention, a current can flow in the thickness direction of the magnetoresistive effect film, and it is possible to obtain a higher MR ratio than before. Further, it can be manufactured without causing an electric short circuit at the side portion of the magnetoresistive effect film.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magnetoresistive element according to one embodiment of the present invention.

FIG. 2 is a plan view showing the magnetoresistive element of the embodiment shown in FIG.

FIG. 3 is a sectional view for explaining a manufacturing process of the embodiment shown in FIG. 1;

FIG. 4 is a sectional view showing a structure in which a magnetic domain control layer is provided in the embodiment shown in FIG. 1;

FIG. 5 is a sectional view showing a magnetoresistive element according to another embodiment of the present invention.

FIG. 6 is a sectional view showing a magnetoresistive element according to still another embodiment of the present invention.

FIG. 7 is a sectional view showing a magnetoresistive element according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Lower electrode layer 3 ... Protective layer 8 ... Upper electrode layer 9 ... Resist film 10, 20, 30, 40 ... Magnetoresistance effect film 11, 12 ... Electrode lead layer

Claims (8)

[Claims] 1. A method for selectively etching a magnetoresistive element on a lower electrode layer so as to leave the magnetoresistive film in a magnetic field detection region, and provided on the magnetoresistive film. In a magnetoresistive effect element for detecting a change in a magnetic field from a change in electric resistance by flowing a current between an upper electrode layer and the lower electrode layer, a region on the lower electrode layer other than at least the magnetic field detection region Wherein a protective film is provided for the etching. 2. The magnetoresistance effect element according to claim 1, wherein said magnetoresistance effect film is a magnetoresistance effect film having a laminated structure of a ferromagnetic layer and a nonmagnetic conductive layer. 3. The magnetoresistive element according to claim 1, wherein the magnetoresistive film has a laminated structure in which a nonmagnetic insulating layer is sandwiched between a pair of ferromagnetic layers. 4. The method according to claim 1, wherein the protective film is made of Ta, Zr, Hf, P
b, Sr, Ti, U, V, Nb, Re, Sb, and Te
The magnetoresistive element according to any one of claims 1 to 3, wherein the magnetoresistive element is formed of at least one material selected from the group consisting of: 5. A method for manufacturing a magnetoresistive element in which a magnetoresistive film is provided in a magnetic field detection region between a lower electrode layer and an upper electrode layer, wherein a protective film is formed on the lower electrode layer. Performing the step of: forming the magnetoresistive film on the protective film; and forming a region of the magnetoresistive film other than the magnetic field detection region,
Etching until reaching the inside of the protective film, and patterning so as to leave the magnetoresistive film in the magnetic field detection region, wherein in the etching step, a side portion of the magnetoresistive film of the lower electrode layer material A method of manufacturing a magnetoresistive element, wherein the adhesion of the protective film is prevented by the presence of the protective film. 6. The method according to claim 5, further comprising a step of forming the upper electrode layer on the magnetoresistive film before the etching step, wherein the upper electrode layer and the magnetoresistive film are etched in the etching step. A method for manufacturing the magnetoresistive element according to the above. 7. The method according to claim 5, further comprising the step of selectively forming the upper electrode layer on the magnetoresistive film after the etching step. 8. The method according to claim 1, wherein the protective film is made of Ta, Zr, Hf, P
b, Sr, Ti, U, V, Nb, Re, Sb, and Te
The method for manufacturing a magnetoresistive element according to any one of claims 5 to 7, wherein the method is formed from at least one material selected from the group consisting of: