JPH087223A - Thin film magnetic head and its production - Google Patents

Abstract

PURPOSE:To prevent undershoot and production of side fringing magnetic field without subjecting a magnetic pole layer to physical processing by locally deteriorating the magnetic characteristics of the magnetic pole layer in a part of the surface facing a medium by a specified depth from the surface facing the medium. CONSTITUTION:The lower magnetic pole layer 2 and upper magnetic pole layer 6 have magnetically deteriorated parts 20, 60 formed in a part of the surface facing the medium, and in these deteriorated parts, magnetic characteristics are deteriorated by a specified depth L from the surface facing the medium. By forming these magnetically deteriorated parts 20, 60, undershoot and production of side fringing magnetic field can be prevented. Concretely, the area 20a except the magnetically deteriorated part 20 of the lower magnetic pole layer 2 is formed to have width L1 (perpendicular to the traveling direction a of the medium) on the gap layer 3 side almost the same as the track width Tw. By this method, no magnetic field is produced from the magnetically deteriorated part 20, so that production of side fringing magnetic field can be prevented without subjecting the lower magnetic pole layer 2 and the upper magnetic pole layer 6 to physical processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a lower magnetic pole layer on a substrate,
The present invention relates to a thin film magnetic head in which a gap layer and a top pole layer are formed and a manufacturing method thereof.

[0002]

2. Description of the Related Art A conventional thin-film magnetic head has a lower magnetic pole layer formed on a substrate, a gap layer formed on the lower magnetic pole layer, and an upper magnetic pole layer formed on the gap layer. . Here, FIG. 5 shows a reproduction waveform (a) of a conventional thin film magnetic head (an isolated reproduction waveform obtained by reproducing a signal of one shot recorded on a magnetic recording medium) and a pole layer structure (b). As shown in FIG. 5, the reproduced waveform is the upper magnetic pole layer 50.
a, pseudo-waveform undershoots A and B occur at positions corresponding to the edges of the lower magnetic pole layer 50b. The undershoots A and B occur due to the structure peculiar to the thin film magnetic head. That is, in the thin film magnetic head, unlike the bulk type magnetic head and the like, since the thickness of the end portions of the upper magnetic pole layer 50a and the lower magnetic pole layer 50b in the medium scanning direction a is thin and finite, the original conversion by the gap film is performed. This is because, in addition to the gap magnetic flux, pseudo gap magnetic fluxes Fx and Fy are generated by the respective end portions X and Y of the upper magnetic pole layer 50a and the lower magnetic pole layer 50b. In the case of high recording density, the presence of the undershoots A and B causes a large peak shift, so that a read error margin or a phase margin is limited, which hinders high-density recording. Further, in the conventional thin film magnetic head, the width in the direction perpendicular to the medium scanning direction a on the medium facing surface is limited to the top pole layer 50 due to manufacturing and structural restrictions.
The size a is smaller than the bottom pole layer 50b. With such a configuration, a magnetic field (side fringing magnetic field) Fs is generated from the side portion of the top pole layer 50a in addition to the original magnetic field generated in the gap during recording. When the side fringing magnetic field Fs is generated, the reproduced waveform is disturbed, and the amplitude of the pulse is changed or the pulse position is changed, resulting in deterioration of the error rate. Techniques related to this include, for example, JP-A-4-13209, JP-A-5-189720, and JP-A-6-36236.

[0003]

As described above, in the conventional thin film magnetic head, the undershoot and the side fringing magnetic field are generated due to the restrictions on the manufacturing method and the structure. In order to prevent the noise or the error rate from deteriorating, it is necessary to prevent both the undershoot and the side fringing magnetic field. First, in order to prevent undershoot, the width of the pole layer (the medium scanning direction) may be made different throughout the pole layer. That is, the outer peripheral contour line of the pole layer on the medium facing surface may be made non-parallel to the gap layer. On the other hand, in order to prevent the occurrence of the side fringing magnetic field, the widths of the medium facing surface in the direction perpendicular to the medium scanning direction may be made equal in the upper magnetic pole layer and the lower magnetic pole layer. As described above, in order to prevent the occurrence of undershoot and side fringing magnetic field, the widths of the pole layers are made different throughout, and the width in the direction perpendicular to the medium scanning direction is made equal in the top pole layer and the bottom pole layer. It should be done. In this case, in a magnetic head other than a thin film (bulk type magnetic head, etc.), the width of the pole layer (medium scanning direction) is several tens of times as large as that of the thin film magnetic head. Since it is easy to process into the above, it is not necessary to consider the above problems. However, in the case of a thin film magnetic head, it is often difficult to realize the above shape by photolithography technology, sputtering technology, etc.
As one method for realizing the above shape, for example, ion milling may be used. A fine processing method utilizing this ion milling will be described with reference to FIG.
(A) is before processing and (b) is after processing. First, as shown in FIG. 4A, from the medium facing surface side (sliding surface side), a resist 40c having a predetermined shape is formed on the sliding surface and a part of the upper magnetic pole layer 40a and the lower magnetic pole layer 40b. After that, ion milling is performed on the entire surface from the medium facing surface side. As a result, the resist 40c functions as a mask, and the portion other than the portion coated with the resist 40c has a thickness of 0.
It is scraped by about 5 to 1 μm. As a result, the top pole layer 40
a, the bottom pole layer 40b is physically processed into a shape as shown in FIG. However, in such a method, since the recess 40d of about 0.5 to 1 μm is formed in the medium facing surface, the floating characteristic becomes unstable, and dust and the like are entrained, which is not preferable. Furthermore, when the recess 40d is formed by ion milling, the scraped material adheres to the surroundings, so that a lapping process or the like must be performed at the end and an extra process is required. Moreover, since the periphery of the pole layer (40a, 40b) which is the core portion is recessed, the pole layer (40a, 40b) is formed at the time of lapping.
There is a possibility that b) is recessed from the medium facing surface. For this reason, it is difficult to realize the above-mentioned shape with high accuracy by physical processing in the thin film magnetic head without lowering the yield and the like.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and its object is to:
It is to prevent the undershoot and the side fringing magnetic field from being generated without physically processing the pole layer.

[0005]

To achieve the above object, in a thin film magnetic head of the present invention, a lower magnetic pole layer formed on a substrate, a gap layer formed on the lower magnetic pole layer, and a gap. A top pole layer formed on the layer,
In a thin film magnetic head in which the width of the medium facing surface in the direction perpendicular to the medium scanning direction is smaller in the upper magnetic pole layer than in the lower magnetic pole layer, the magnetic characteristics of a part of the medium facing surface of the upper magnetic pole layer and the lower magnetic pole layer are The magnetically deteriorated portion is deteriorated by a predetermined depth from the medium facing surface. The depth of the magnetically deteriorated portion from the medium facing surface is preferably 1 μm or less. Further, the width of the portion other than the magnetically deteriorated portion of the lower magnetic pole layer on the gap layer side (direction perpendicular to the medium scanning direction) is substantially equal to the track width. Further, the inner peripheral contour line of the magnetically deteriorated portion on the medium facing surface is not parallel to the gap layer. In the method of manufacturing a thin film magnetic head of the invention, the lower magnetic pole layer is formed on the substrate, the gap layer is formed on the lower magnetic pole layer, the upper magnetic pole layer is formed on the gap layer, and the medium on the medium facing surface is formed. In a method of manufacturing a thin-film magnetic head that is formed so that its width in the direction perpendicular to the scanning direction is smaller than that of a bottom pole layer, impurities are ion-implanted from a medium facing surface through a mask of a predetermined shape to a predetermined depth. Thus, the magnetic characteristics of a part of the medium facing surface of the upper magnetic pole layer and the lower magnetic pole layer are deteriorated by a predetermined depth from the medium facing surface. The track width can be variably set by changing the shape of the mask. Further, in another method of manufacturing a thin film magnetic head of the present invention, a lower magnetic pole layer is formed on a substrate, a gap layer is formed on the lower magnetic pole layer, an upper magnetic pole layer is formed on the gap layer, and a medium facing surface is formed. In a method of manufacturing a thin-film magnetic head in which the width in the direction perpendicular to the medium scanning direction is smaller than that of the lower magnetic pole layer, an impurity layer is laminated on a part of the medium facing surface of the lower magnetic pole layer and the upper magnetic pole layer, and then, By diffusing the impurities to a predetermined depth from the medium facing surface by the thermal diffusion method, a part of the magnetic characteristics of the medium facing surface of the upper magnetic pole layer and the lower magnetic pole layer is deteriorated by a predetermined depth from the medium facing surface. The track width can be variably set by changing the shape of the impurity layer.

[0006]

According to the present invention, the undershoot and the side fringing magnetic field can be prevented by degrading the magnetic characteristics of a part of the medium facing surface of the upper magnetic pole layer and the lower magnetic pole layer by a predetermined depth from the medium facing surface. The shape is realized magnetically. That is, the above shape is not realized by physical processing such as ion milling, but is realized by degrading a part of the magnetic properties of the pole layer. By doing so, undershoot and side fringes can be prevented while preventing instability of the levitation characteristics, reduction in yield, reduction in processing accuracy, etc. that occur due to physical processing (for example, the pole layer is cut by ion milling). It is possible to effectively prevent the generation of a magnetic field. The depth of the magnetically deteriorated portion from the medium facing surface is preferably 1 μm or less.
The width of the portion other than the magnetically deteriorated portion of the bottom pole layer on the side of the gap layer (direction perpendicular to the medium scanning direction) is substantially equal to the track width. By doing so, it becomes possible to prevent the side fringing magnetic field from being generated without physically processing the pole layer. Further, the inner peripheral contour line on the medium facing surface of the magnetically deteriorated portion is not parallel to the medium scanning direction. By doing so, it is possible to prevent the occurrence of undershoot without performing physical processing on the pole layer. To form the magnetically deteriorated portion, impurities are implanted to a prescribed depth from the medium facing surface through a mask having a prescribed shape by an ion implantation method. Alternatively, an impurity layer may be laminated from the medium facing surface to a part of the pole layer, and then the impurities may be diffused to a predetermined depth from the medium facing surface by a thermal diffusion method. At that time, the track width can be variably set by changing the shape of the mask or the shape of the impurity layer.

[0007]

Embodiments of the present invention will be described with reference to the drawings. First,
The physical structure of the thin film magnetic head of the present invention is shown in FIG. 2A is a cross-sectional view of a main part, and FIG. 2B is an enlarged view of the medium facing surface side. The lower magnetic pole layer 2 is formed on the substrate 1, and the gap layer 3 is formed on the lower magnetic pole layer 2. The coil layer 5 is formed on the gap layer 3 with the insulating layer 4 interposed therebetween. Further, the upper magnetic pole layer 6 is formed on the coil layer 5.

The tip portions of the lower magnetic pole layer 2 and the upper magnetic pole layer 6 are ball portions 2a, 6a opposed to each other with a gap layer 3 interposed therebetween.
Therefore, reading and writing from and to the magnetic recording medium are performed at the ball portions 2a and 6a. The upper magnetic pole layer 6 is coupled to the lower magnetic pole layer 2 by the coupling portion 7 in the rear region on the side opposite to the ball portion 6a. The coil layer 5 is formed so as to spirally rotate around the coupling portion 7.

The ball portions 2a and 6a have a substantially constant thickness when viewed in the medium scanning direction a, and have a structure in which the gap layer 3 is linearly arranged between them. The width of the medium facing surface in the direction perpendicular to the medium scanning direction a is smaller in the upper magnetic pole layer 6 than in the lower magnetic pole layer 2.

In the present invention, as shown in FIG. 1, the magnetic characteristics of a part of the medium facing surface of the lower magnetic pole layer 2 and the upper magnetic pole layer 6 are deteriorated by a predetermined depth (L) from the medium facing surface. The magnetically deteriorated portions 20 and 60 were formed. By forming such magnetically deteriorated portions 20 and 60, generation of undershoot and side fringing magnetic field is prevented. That is, in the present invention, the shape for preventing the occurrence of undershoot and side fringing magnetic field is not realized by physical processing such as ion milling as shown in FIG. It is realized artificially by degrading some magnetic properties.

Specifically, the width L1 of the portion 20a other than the magnetically deteriorated portion 20 of the bottom pole layer 2 on the side of the gap layer 3 (direction perpendicular to the medium scanning direction a) is formed to be substantially equal to the track width (Tw). ing. In this way, no magnetic field is generated from the magnetically deteriorated portion 20, so that the side fringing magnetic field (see FIG. 5B) can be generated even if the lower magnetic pole layer 2 and the upper magnetic pole layer 6 are not physically processed. Occurrence can be prevented.

Further, the inner peripheral contour lines 20b and 60b on the medium facing surface of the magnetically deteriorated portions 20 and 60 are formed non-parallel to the gap layer 3. That is, the bottom pole layer 2,
The width of the top pole layer 6 in the medium scanning direction a is made different throughout the pole layer. By doing so, it is possible to prevent the occurrence of undershoot (see FIG. 5A) even if the lower magnetic pole layer 2 and the upper magnetic pole layer 6 are not physically processed. Here, the depth (L) from the medium facing surface of the magnetically deteriorated portions 20 and 60 is 1 μm.
The following is preferred.

Next, a method of manufacturing the thin film magnetic head of the present invention will be described. To form the magnetically deteriorated portions 20 and 60,
As shown in FIG. 3A, impurities are implanted from the medium facing surface to a prescribed depth by an ion implantation method through a mask 8 having a prescribed shape. Specifically, by the ion implantation method,
Chromium (Cr), Niobium (Nb), Zirconium (Z
A metal ion such as r) is implanted as an impurity. At this time, the saturation flux density may be lowered by changing the composition of the pole layers 2 and 6 by appropriately selecting the conditions such as the amount of impurities to be injected, or changing the crystallinity of the pole layers 2 and 6 and changing the magnetic permeability. May be reduced.

The magnetically deteriorated portions 20 and 60 may be formed by a thermal diffusion method instead of the ion implantation method. In this case, as shown in FIG. 3B, an impurity layer 9 such as a chromium layer is laminated on a part of the medium facing surface of the lower magnetic pole layer 2 and the upper magnetic pole layer 6, and then heated to remove the impurities from the medium. Diffuse from the surface to a predetermined depth. After diffusing impurities,
When the surface roughness of the medium facing surface is rough, machining such as lapping may be performed. At this time, the mask 8 (see FIG.
The track width Tw can be variably set by changing the shape of (a)) or the shape of the impurity layer 9 (FIG. 3B). The shape of the mask 8 is shown in FIG.
Other than the elliptical shape shown in (a), other shapes such as a trapezoid or a triangle can be appropriately adopted.

[0015]

According to the present invention, the magnetic characteristics of a part of the medium facing surface of the pole layer are deteriorated by a predetermined depth from the medium facing surface, so that the undershoot and the undershoot can be achieved without performing physical processing on the pole layer. Generation of a side fringing magnetic field can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a magnetic shape of a magnetically deteriorated portion of a pole layer of a thin film magnetic head of the present invention.

2A and 2B are views showing a physical structure of a thin film magnetic head of the invention, FIG. 2A is a sectional view of a main part, and FIG. 2B is an enlarged view seen from the medium facing surface side.

3A and 3B are diagrams illustrating a method of manufacturing a thin film magnetic head, in which FIG. 3A shows a case by an ion implantation method and FIG. 3B shows a case by a thermal diffusion method.

FIG. 4 is a comparative example showing a method of manufacturing a thin film magnetic head.

5A is a diagram showing a reproduced waveform of a conventional thin film magnetic head, and FIG. 5B is a diagram showing a configuration of a magnetic pole layer of the conventional thin film magnetic head.

[Explanation of symbols]

 1 Substrate 2 Lower Pole Layer 3 Gap Layer 6 Upper Pole Layer 8 Mask 9 Impurity Layer 20,60 Magnetic Deterioration Part

Claims (8)

[Claims] 1. A lower magnetic pole layer formed on a substrate, a gap layer formed on the lower magnetic pole layer, and an upper magnetic pole layer formed on the gap layer. In a thin film magnetic head whose width in the direction perpendicular to the medium scanning direction is smaller in the upper magnetic pole layer than in the lower magnetic pole layer, the magnetic characteristics of a part of the medium facing surface of the upper magnetic pole layer and the lower magnetic pole layer are
A thin film magnetic head having a magnetically deteriorated portion which is deteriorated by a predetermined depth from a medium facing surface. 2. A thin film magnetic head according to claim 1, wherein the depth of the magnetically deteriorated portion from the medium facing surface is 1 μm or less. 3. The thin film magnetic according to claim 1, wherein the width of the portion other than the magnetically deteriorated portion of the lower pole layer on the side of the gap layer (direction perpendicular to the medium scanning direction) is substantially equal to the track width. head. 4. A thin film magnetic head according to claim 1, wherein an inner peripheral contour line of the magnetically deteriorated portion on the medium facing surface is not parallel to the gap layer. 5. A lower magnetic pole layer is formed on a substrate, a gap layer is formed on the lower magnetic pole layer, an upper magnetic pole layer is formed on the gap layer, and a width in a direction perpendicular to a medium scanning direction on a medium facing surface is formed. In a method of manufacturing a thin film magnetic head that is formed so as to be smaller than a lower magnetic pole layer, impurities are implanted from a medium facing surface to a predetermined depth by an ion implantation method through a mask having a predetermined shape, and thereby the upper magnetic pole layer and the lower magnetic pole layer are formed. A method of manufacturing a thin-film magnetic head, characterized in that the magnetic characteristics of a part of the medium facing surface of the pole layer are deteriorated by a predetermined depth from the medium facing surface. 6. The method of manufacturing a thin film magnetic head according to claim 5, wherein the track width can be variably set by changing the shape of the mask. 7. A lower magnetic pole layer is formed on a substrate, a gap layer is formed on the lower magnetic pole layer, an upper magnetic pole layer is formed on the gap layer, and a width of the medium facing surface in a direction perpendicular to a medium scanning direction is set. In a method of manufacturing a thin film magnetic head that is formed so as to be smaller than the lower magnetic pole layer, an impurity layer is laminated on a part of the medium facing surface of the lower magnetic pole layer and the upper magnetic pole layer, and then impurities are diffused by a thermal diffusion method. To a predetermined depth, the magnetic characteristics of a part of the medium facing surface of the upper magnetic pole layer and the lower magnetic pole layer are deteriorated by a predetermined depth from the medium facing surface. 8. A method of manufacturing a thin film magnetic head according to claim 7, wherein the track width can be variably set by changing the shape of the impurity layer.