JPH0855310A - Magnetoresistive effect head - Google Patents

Abstract

PURPOSE:To solve a problem of short circuits between an electrode and magnetic shield layers in a magnetoresistive effect head and to narrow the magnetic gap. CONSTITUTION:Nonconductive magnetic ferrite layers 7a, 8a are formed between insulating layers 3a, 3b and metal magnetic layers 7b, 8b for shielding so that magnetic shield layers 7, 8 have a two-layer composite structure of the nonconductive magnetic ferrite layers 7a, 8a and metal magnetic layers 7a, 8b. By this method, short circuits between an electrode 5 and metal magnetic shield layers (metal magnetic layers 7b, 8b) can be prevented and the effective magnetic gap can be rendered narrower since the nonconductive magnetic ferrite layers 7a, 8a act as a magnetic shield with metal magnetic layers 7b, 8b. Thus, the obtd. magnetoresistive effect head is suitable for high recording density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a thin film magnetic head using a magnetoresistive effect element used for reading (reproducing) a high density recording medium, and a magnetic shield layer is made of a non-conductive magnetic ferrite layer. The present invention relates to a magnetoresistive head which is composed of two composite layers of a metal magnetic layer and prevents an electrode having a step portion and a metal magnetic shield layer from being short-circuited to achieve an effective narrow magnetic gap.

[0002]

2. Description of the Related Art In a magnetic disk device used as a high-density recording medium, there is a demand for extremely high recording capacity, downsizing, and high signal transmission speed. A thin film magnetic head using a resistance effect element is adopted.

[0003] The configuration of a magneto-resistive head, to describe in cross-sectional view as seen from the air bearing surface direction of the conventional magnetoresistive head of FIG. 2, for example, NiFe alloy on Al ₂ O ₃ -TiC substrate 1 The MR3 layer having a three-layer structure in which the magnetoresistive effect film, the magnetic separation film, and the bias film are laminated on the insulating layer 3a made of Al ₂ O _{3 which} is the lower gap layer. A film 4 is formed, an electrode 5 is formed on the film 4, and an insulating layer 3b made of Al ₂ O ₃ to be an upper gap layer is further formed to form a magnetic shield layer 2b made of a NiFe alloy. The protective film 6 is formed to complete the head.

[0004]

In the magnetoresistive head having the above structure, in order to achieve the above-mentioned high density, it is necessary to narrow the upper and lower magnetic shield layers to reduce the total gap. However, when the gap is made small, the electrode having the step portion and the magnetic shield layer are often short-circuited in many cases, resulting in a large decrease in the yield of the wafer. For the purpose of preventing short circuit between the electrode and the magnetic shield layer, a wide and thin electrode shape is adopted,
Even with this method, the electrode thickness and the gap thickness are almost equal, and the drawback of short-circuiting has not been solved.

It is an object of the present invention to provide a magnetoresistive head having a structure capable of narrowing the magnetic gap by solving the problem of short circuit between the electrode and the magnetic shield layer in the conventional magnetoresistive head.

[0006]

DISCLOSURE OF THE INVENTION The inventor of the present invention aims to solve the problem of a short circuit between an electrode and a magnetic shield layer in a magnetoresistive head and to narrow the magnetic gap.
As a result of various studies on the magnetic shield layer, by forming a non-conductive ferrite between the metal magnetic shield layer and the insulating layer, it helps prevent short circuit between the electrode and the metal magnetic shield layer, and also together with the metal magnetic shield layer, the magnetic shield layer. The present invention has been completed based on the finding that the magnetic gap distance does not widen because it also plays a role of.

That is, according to the present invention, in a magnetoresistive effect type head having a magnetic shield layer via an insulating layer so as to sandwich a three-layer structure magnetoresistive element, one or both of the magnetic shield layers are provided from the insulating layer side. A magnetoresistive head comprising a composite layer of two layers of a non-conductive magnetic ferrite layer and a metal magnetic layer.

Further, according to the present invention, in the structure of the magnetoresistive head described above, the non-conductive magnetic ferrite layer is a material having a specific resistance of 10 ⁵ Ωcm or more, and the non-conductive magnetic ferrite layer thickness is 0.03 μm. .About.0.4 .mu.m.

In the present invention, the non-conductive magnetic ferrite layer constituting the magnetic shield layer preferably has a specific resistance of 10 ⁵ Ωcm or more, such as NiZn ferrite, and a film thickness of 0.03 μm or more. Although sufficient, ferrite generally has a lower magnetic permeability than metal magnetic materials,
Since the saturation magnetic flux density is small, if the film thickness exceeds 0.4 μm, the effective gap length of the magnetic head becomes long, which is not preferable. Further, as the metal magnetic layer, NiFe-based or CoZr-based amorphous having a higher magnetic permeability than ferrite can be used.

[0010]

The operation of the magnetoresistive head according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of the magnetoresistive head viewed from the air bearing surface direction. In the example shown in A of FIG. 1, a magnetic shield layer 2a made of, for example, a NiFe alloy is provided on a substrate 1, and a magnetoresistive film and a magnetic resistance film are formed on an insulating layer 3a made of Al ₂ O ₃ or the like serving as a lower gap layer. MR three-layer film 4 having a three-layer structure in which a separation film and a bias film are laminated.
Is formed, an electrode 5 is formed thereon, and an insulating layer 3b made of Al ₂ O ₃ or the like serving as an upper gap layer is further formed. A non-conductive magnetic ferrite layer 7a made of NiZn-based ferrite is formed on the insulating layer 3b, and then N
A metal magnetic layer 7b made of an iFe alloy is provided to form a magnetic shield layer 7 made of two composite layers, and a protective film 6 is further formed.
Are laminated to form a film.

The electrode 5 is formed by forming a non-conductive magnetic ferrite layer 7a between the metal magnetic layer 7b and the insulating layer 3b.
In addition to helping prevent a short circuit of the metal magnetic layer 7b, which is a magnetic shield layer, and also functions as a magnetic shield together with the metal magnetic layer 7b, the effective magnetic gap can be set narrow. On the other hand, as shown in FIG. 1C, the lower magnetic shield layer of the MR three-layer film 4 in which the electrodes are not formed in the above-described structure may be the magnetic shield layer 8 composed of two composite layers of the present invention. it can. That is, Ni on the substrate 1
The metal magnetic layer 8b made of an Fe alloy is formed, and then the non-conductive magnetic ferrite layer 8a is formed, and then the insulating layer 3a is provided.

In the example shown in FIG. 1A, the electrode 5 is formed only on the upper side of the MR3 layer film 4, but the electrode is MR3.
When it is arranged on both sides of the layer film 4, as shown in FIG. 1B, the metal magnetic layer 8b is formed on the substrate 1, and the non-conductive magnetic layer ferrite 8a is formed to form a magnetic layer composed of a composite layer. After the shield layer 8 is provided, the insulating layer 3a is formed, the electrode 5a is patterned, then the MR3 layer film 4 is formed, and further, the electrode 5b is provided and then the insulating layer 3b is formed. A non-conductive magnetic ferrite layer 7a is formed and a metal magnetic layer 7b is formed.
The magnetic shield layer 7 made of a composite layer is provided by stacking the above layers to prevent a short circuit between the electrodes 5a, 5b and the metal magnetic layers 7b, 8b by the non-conductive magnetic ferrite layers 7a, 8a.

[0013]

【Example】

Example 1 ₂ μm of NiFe was plated on an Al ₂ O ₃ —TiC substrate.
to form a lower magnetic shield layer on which Al ₂ O _{3 is formed.}
Was deposited to a thickness of 0.15 μm to form a lower insulating layer. A three-layer MR element having a CoZrMo film as a soft film, a Ti magnetic separation film, and a NiFe film magnetoresistive film was formed on the lower insulating layer. The three-layer MR element has a thickness of 0.05 μm, a length of 60 μm, and a width of 5 μm. On top of this, a Cu electrode of 0.2 μm is formed so that the track width becomes 6 μm.
m. Al ₂ O ₃ is used as the upper insulating layer in an amount of 0.1
After forming a film with a thickness of 8 μm, a non-conductive ferrite of Ni—Zn is added to 0.01 μm, 0.03 μm, 0.05 μm, 0.1
μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μ
8 kinds of structures each having a thickness of m were prepared, and a NiFe film was further formed by plating to a thickness of 2 μm to form a metal magnetic layer and then a terminal portion was formed to protect the Al ₂ O ₃ film. A 30 μm layer was deposited to complete the wafer process. After the terminal processing, a gold pad was formed, cut, polished, and assembled to prepare a magnetic head. For comparison, a conventional structure having a structure in which a NiFe film is formed to a thickness of 2 μm and a magnetic shield layer is laminated in the above-described structure without providing a non-conductive ferrite of Ni—Zn is manufactured, and a magnetic field is formed by the same method. I made it a head.

Table 1 shows the relationship between the electrical characteristics at the wafer stage, the read signal characteristics of the completed magnetic head, and the thickness of the non-conductive ferrite layer of Ni-Zn.
When the non-conductive ferrite layer of Zn was 0.03 μm, the short circuit between the electrode and the metal magnetic layer was significantly reduced, and when it was 0.05 μm or more, there was almost no short circuit and the stability was stable. Also, Ni-Z
If the non-conductive ferrite layer of n is 0.4 μm or less, the full width at half maximum of the signal corresponding to the effective gap length obtained from the read signal is 0.38 μm, and there is no non-conductive ferrite layer of Ni—Zn. However, since the effective gap length increases to 0.40 μm when the Ni—Zn non-conductive ferrite layer is 0.5 μm, the thickness of the non-conductive ferrite layer is 0.05 μm to 0.4 μm. I find it desirable.

Example 2 A CoZr-based amorphous metal film having a thickness of 1.8 μm was formed on an Al ₂ O ₃ —TiC substrate by sputtering to form a metal magnetic layer, and Ni—Zn non-conductive ferrite was removed by ion beam sputtering. 0.01 μm, 0.03 μm, 0.05 μm,
0.1 μm, 0.2 μm, 0.4 μm, 0.5 μm 7
The lower magnetic shield layer was formed by depositing films of different types. An Al ₂ O ₃ film having a thickness of 0.10 μm was formed thereon to form a lower insulating layer. Further, a three-layer MR in which the CoZrMo film is a soft film, the Ti is a magnetic separation film, and the NiFe film is a magnetoresistive film.
The device was formed. The thickness of the 3-layer MR element is 0.05 μm
And the length is 100 μm and the width is 4 μm. Furthermore, the Cu electrode is set to 0.10μ so that the track width becomes 5μm.
m. Al ₂ O ₃ was used as the upper insulating layer.
After forming the film with a thickness of 08 μm, a non-conductive ferrite of Ni—Zn is formed with the same thickness as in the case of the lower magnetic shield layer, and further CoZr-based amorphous metal is used as a metal magnetic layer.
A film having a thickness of 8 μm was formed to form an upper magnetic shield layer. After that, a terminal portion is formed and a protective layer of Al ₂ O ₃ film is formed to 30 μm.
A film was formed and the wafer process was completed. After the terminal processing, a gold pad was formed, cut, polished, and assembled to prepare a magnetic head.

Table 2 shows the relationship between the electrical characteristics at the wafer stage, the read signal characteristics of the completed magnetic head, and the thickness of the non-conductive ferrite layer of Ni-Zn.
When the non-conductive ferrite layer of n was 0.03 μm, the short circuit between the electrode and the metal magnetic layer was greatly reduced, and when it was 0.05 μm or more, there was almost no short circuit and it was stable. In addition, Ni-Zn
If the non-conductive ferrite layer of 4 is 0.4 μm or less, the full width at half maximum of the signal corresponding to the effective gap length obtained from the read signal is 0.24 μm, and there is no Ni-Zn non-conductive ferrite layer. Although equivalent, the effective gap length increases to 0.28 μm when the Ni-Zn non-conductive ferrite layer becomes 0.5 μm, so the thickness of the non-conductive ferrite layer is preferably 0.05 μm to 0.4 μm. It was confirmed.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

According to the present invention, as a magnetic shield layer, a non-conductive ferrite film is formed between an insulating layer and a metal magnetic layer for shielding to form a two-layer structure of a non-conductive magnetic ferrite layer and a metal magnetic layer. The composite layer structure of helps to prevent short circuit between the electrode and the metal magnetic shield layer (metal magnetic layer), and the non-conductive magnetic ferrite layer also plays the role of magnetic shield together with the metal magnetic layer, so that the effective magnetic The gap can be set narrow, and it is optimal as a magnetoresistive head for high recording density.

[Brief description of drawings]

1A, 1B, and 1C are cross-sectional explanatory views showing the structure of a magnetoresistive head according to the present invention as seen from the air bearing surface direction.

FIG. 2 is a cross-sectional explanatory view showing a configuration of a conventional magnetoresistive head, viewed from the air bearing surface direction.

[Explanation of symbols]

 1 Substrate 2a, 2b Magnetic shield layer 3a, 3b Insulating layer 4 MR3 layer film 5, 5a, 5b Electrode 6 Protective film 7, 8 Magnetic shield layer 7a, 8a Non-conductive magnetic ferrite layer 7b, 8b Metal magnetic layer

Claims (1)

[Claims] 1. In a magnetoresistive effect type head having a magnetic shield layer with an insulating layer sandwiching a three-layer structure magnetoresistive element, one or both of the magnetic shield layers are electrically non-conductive from the insulating layer side. Ferrite layer and metallic magnetic layer 2
A magnetoresistive head comprising a composite layer of layers.