JPH09128710A - Thin-film magnetic head and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the warpage of a substrate in a stage for forming a thin-film magnetic head element and to prevent the peeling of the thin films of respective layers and the deterioration in the characteristics thereof by forming compensation thin films for relieving the camber of the substrate on the rear surface of the substrate. SOLUTION: A ground surface layer 21 of about 10μm thickness consisting essentially of Al2 O3 , the thin-film magnetic head element 3 consisting of various kinds of the thin-film layers and a protective layer 4 of about 30μm thickness consisting of a material constituting. Al2 O3 as its essential component are formed on the surface of the substrate 1 consisting of a material contg. Al2 O3 -TiC as its essential component and having about 2mm thickness. The compensation thin film 22 consisting of the material contg. the Al2 O3 as its essential component and having about 10μm thickness is formed on the rear surface of the substrate 1. The Al2 O3 film on the rear surface side is merely necessitated to be formed in the state of applying a photoresist 5, etc., of about 4μm thickness on the front surfaces side of the substrate when the substrate formed with the Al2 O3 film only on the front surface side and formed with the polished front surface is previously prepd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head used in a magnetic storage device such as a hard disk drive.

[0002]

2. Description of the Related Art In a floating type thin film magnetic head mounted in a hard disk drive or the like, as shown in FIG. 3, an air bearing portion 19 for slightly traveling above a magnetic disk serving as a magnetic recording medium for relative travel. On the side surface of the slider base 1 having the magnetic field, a magnetoresistive thin film magnetic head element 31 for signal reproduction, an inductive thin film magnetic head element 32 for signal recording, and a lead conductor layer 33 for connecting both head elements to an external circuit. Etc. are formed.

In the manufacturing process of such a thin film magnetic head slider, as shown in FIG. 4, a magnetoresistive effect type and induction type thin film magnetic film is formed on a substrate 1 serving as a slider base through an underlayer 21 having a thickness of about 10 μm. The head element 3 is formed, and the protective layer 4 having a thickness of about 30 μm is further formed thereon.
A typical material of the substrate is Al ₂ O ₃ —TiC, and a typical material of the underlayer and the protective layer is Al ₂ O ₃ .

The underlayer is provided in order to flatten the film-forming underlayer surface of each thin film constituting the thin film magnetic head element. That is, the material of the substrate that becomes the slider base is Al ₂
Since two phases of O ₃ and TiC are mixed, even if the surface of the substrate is polished, minute unevenness remains, and if a thin film magnetic head element is directly formed on the uneven surface, the element is formed. Concavities and convexities also occur in each thin film, and the magnetic properties, conductivity, insulation, etc. of the thin film become unstable. Therefore, a flat surface can be obtained by forming an underlayer made of a single material such as Al ₂ O ₃ on the substrate and polishing the surface. If a thin film magnetic head element is formed on the flat surface, The problem of unevenness does not occur.

On the other hand, the protective layer physically and chemically protects the thin film magnetic head element during a machining process after the thin film magnetic head element is formed or during practical use after the thin film magnetic head element is incorporated into a hard disk drive device or the like. It is provided for this purpose.

[0006]

By the way, in the step of forming the thin film magnetic head element on the substrate on which the underlayer is formed, heat for forming and etching each layer thin film forming the thin film magnetic head element is used. A rearrangement of atoms of the thin film forming the underlayer due to history occurs, the substrate warps in response to expansion or contraction of the underlayer thin film, and each layer thin film forming the thin film magnetic head element peels off, The magnetic properties and electrical properties of the thin film may deteriorate.

For example, Al ₂ O ₃ --TiC having a thickness of about 2 mm
To form an Al ₂ O ₃ film having a thickness of about 10μm on the substrate, the residual stress of the Al ₂ O ₃ film after annealing at the temperature between room temperature to 600 ° C., the value shown in FIG. 5 It becomes a compressive stress.

The present invention clarifies the structure of a thin film magnetic head for reducing the above-mentioned warpage of the substrate and a method of manufacturing the thin film magnetic head.

[0009]

A thin-film magnetic head according to the present invention is a thin-film magnetic head in which a thin-film magnetic head element is formed on a surface of a substrate with an underlayer on the back surface of the substrate. The compensation thin film for compensation is formed, and preferably, the compensation thin film is made of the same material as that of the underlayer.

A method of manufacturing a thin film magnetic head according to a preferred embodiment of the present invention comprises a step of forming an underlayer on the front surface of the substrate and a compensation thin film made of the same material as the underlayer on the back surface of the substrate. And a step of annealing the substrate on which the underlayer and the compensation thin film are formed at a temperature higher than the maximum history temperature when forming a thin film magnetic head element in a subsequent step, and a thin film magnetic film on the underlayer. And a step of forming a head element.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The thin film magnetic head according to the present invention embodiment, as shown in FIG. 1, the Al ₂ O ₃ -TiC made of a material mainly composed of a thickness of about 2mm surface of the substrate 1, the Al ₂ O ₃ An underlayer 21 having a thickness of about 10 μm, which is composed of a material as a main component,
Thin film magnetic head element 3 composed of various thin film layers and Al ₂ O ₃
A protective layer 4 made of a material whose main component is about 30 μm thick
And a compensation thin film 22 made of a material containing Al ₂ O ₃ as a main component and having a thickness of about 10 μm is formed on the back surface of the substrate 1.

In the manufacturing process of the thin-film magnetic head according to the above-mentioned embodiment, when the Al ₂ O ₃ film is formed on the front surface and the back surface of the substrate, the Al ₂ O ₃ film on the front surface side is formed slightly thicker than the back surface side. Then, the upper surface of the Al ₂ O ₃ film on the surface side is polished and flattened, and the thicknesses of the Al ₂ O ₃ films on the front and back sides are made substantially equal, and the substrate is heated at a temperature higher than the maximum history temperature in the thin film magnetic head element formation process After annealing, the thin film magnetic head element and the protective layer are formed.

The maximum hysteresis temperature in the thin film magnetic head element forming step is appropriately selected depending on the type of magnetic thin film forming the thin film magnetic head element, but is about 200 ° C. to about 50.
0 ° C.

When an Al ₂ O ₃ film is formed only on the surface side and the substrate whose upper surface is polished is prepared in advance, the polished surface is damaged when the substrate is attached to the film forming apparatus. In order to prevent this, as shown in FIG. 2, the Al ₂ O ₃ film on the back surface side may be formed with the photoresist 5 or the like having a thickness of about 4 μm applied on the front surface side of the substrate.

[0016]

According to the present invention, the warp of the substrate in the step of forming the thin film magnetic head element is reduced, and the peeling and deterioration of the characteristics of each thin film constituting the thin film magnetic head element are prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a thin film magnetic head according to an embodiment of the present invention.

FIG. 2 is a sectional view of a substrate for explaining a method of manufacturing a thin film magnetic head according to an embodiment of the present invention.

FIG. 3 is an external perspective view of a thin film magnetic head according to an embodiment of the present invention and a conventional example.

FIG. 4 is a sectional view of a conventional thin film magnetic head.

FIG. 5 is an experimental result diagram for explaining problems of the conventional example.

[Explanation of symbols]

 1 Substrate 21 Underlayer 22 Compensation Thin Film 3 Thin Film Magnetic Head Element 4 Protective Layer

Claims (4)

[Claims] 1. A thin film magnetic head having a thin film magnetic head element formed on a front surface of a substrate via an underlayer, wherein a compensation thin film for relaxing a warp of the substrate is formed on a back surface of the substrate. Characteristic thin film magnetic head. 2. The thin-film magnetic head according to claim 1, wherein the compensation thin film is made of the same material as the underlayer. 3. The thin film according to claim 2, wherein the substrate is made of a material containing Al ₂ O ₃ —TiC as a main component, and the underlayer is made of a material containing Al ₂ O ₃ as a main component. Magnetic head. 4. A method of manufacturing a thin-film magnetic head in which a thin-film magnetic head element is formed on a surface of a substrate with an underlayer interposed between the substrate, a step of forming an underlayer on the surface of the substrate, and A step of forming a compensation thin film made of the same material as the base layer, and a step of annealing the substrate on which the underlayer and the compensation thin film are formed at a temperature higher than the maximum history temperature when forming a thin film magnetic head element in a subsequent step. And a step of forming a thin film magnetic head element on the underlayer, the method of manufacturing a thin film magnetic head.