JP3555204B2 - Thin film magnetic head - Google Patents

Description

[0001]
[Industrial applications]
This invention relates to thin film magnetic heads, and more specifically, is constituted magnetic circuit by the upper and lower core and intermediate core relates to an improvement of a thin-film magnetic heads suitable for high-density magnetic recording.
[0002]
[Background Art]
As a conventional thin film magnetic head, for example, there is a thin film magnetic head whose main part is shown in FIG. In this example, a winding is stacked on a flat lower core, and the upper core is arranged so as to straddle the winding portion. In the figure, on a lower core 802 formed on a main surface of a substrate 800, a magnetic gap 804 of a nonmagnetic layer, insulating layers 806 and 808 are formed. A coil 810 is formed on the insulating layer 808, and an upper core 812 and a protective film 814 are formed thereon.
[0003]
On the other hand, Japanese Patent Application Laid-Open No. 3-58308 discloses a thin film magnetic head having a structure in which flat upper and lower cores sandwiching a winding portion are connected by a flat intermediate core pattern as shown in FIG. ing. In the figure, a lower core 802 is formed on a substrate 800 via an insulating film (not shown). On the lower core 802, front intermediate cores 820, 822 and rear intermediate cores 824, 826 are formed, respectively.
[0004]
A magnetic gap 828 made of an insulating film is formed between the front intermediate cores 820 and 822, and a coil 810 is formed so as to wind the rear intermediate cores 824 and 826. On the front intermediate core 822 and the rear intermediate core 826, an upper core 830 is formed in an insulating film (not shown). In addition, a protective film 814 is formed on the upper core 830.
[0005]
According to this example, as compared with the example of FIG. 8A, (1) all the magnetic films can be formed flat, so that the characteristics of the magnetic film pattern are not deteriorated. Since it can be performed on a surface, there are advantages such as fine pattern formation and processing. However, at the same time, (1) the magnetic path is completely short, so that the magnetic flux is not smoothly introduced into the gap tip. (2) If the gap depth becomes smaller than the intermediate core thickness, There are also disadvantages, such as that the magnetic path cross-sectional area is reduced and magnetic saturation is likely to occur.
[0006]
In order to improve this problem, Japanese Patent Application Nos. Hei 3-183791 and Hei 5-127822 have been filed. These are formed by interposing a non-magnetic layer called a spacer between the front intermediate cores facing each other across the gap layer while extending in the gap depth direction. In this case, the distance between the magnetic cores is widened, and the leakage magnetic flux at that portion is reduced.
[0007]
FIG. 9A shows a cross section of a main part of a thin-film magnetic head disclosed in Japanese Patent Application No. 5-127822. In the figure, an insulating layer 52 and a lower core 54 are formed flat on a substrate 50, and a front intermediate core 902, a rear intermediate core 58, and an insulating film 60 are formed flat thereon, respectively. I have. A spacer 900 and a coil 68 are formed on the front intermediate core 902 and the insulating film 60 using a nonmagnetic material such as a metal.
[0008]
Next, a magnetic gap 70 made of an insulating material is formed on the main surface of the substrate 50 except for a region where the rear intermediate core is formed, on which the front intermediate core 904 and the rear intermediate core 904 are formed. 74 and an insulating film 76 are formed. A second layer coil 78 is formed on the insulating film 76. The upper core 82 is formed in a portion from the front intermediate core 904 to the rear intermediate core 74, and the insulating film 80 is formed in other portions. Further, lead wires 84 for connecting to the coils 68 and 78 are formed on the insulating film 80.
[0009]
As described above, according to this example, the spacer 900 made of a nonmagnetic material is embedded in the front intermediate core 902. Another front intermediate core 904 is formed on a flat surface. As a result, the deterioration of the magnetic characteristics caused by the formation of the magnetic film on the step, particularly the deterioration of the characteristics at the tip of the magnetic core, can be prevented well. The same conductor as the material of the coil 68 is used as the material of the spacer 900. For this reason, the magnetic shielding effect between the front intermediate cores 902 and 904 sandwiching the magnetic gap 70 is increased, and the magnetic flux leakage can be reduced. Further, the front end of the spacer 900 has an inclined tapered shape. This makes it possible to suppress magnetic saturation of the core portion near the magnetic gap 70.
[0010]
[Problems to be solved by the invention]
However, the above background art has the following disadvantages.
(1) In the application filed as Japanese Patent Application No. 3-183791, a magnetic layer is formed on a step formed by a spacer, so that the magnetic properties of the magnetic layer deteriorate.
[0011]
(2) In the application filed as Japanese Patent Application No. 5-127822, no step occurs because the spacer is buried and flattened. Therefore, the problem of the characteristic deterioration of the magnetic core due to the step as described above is solved. However, the thickness of the spacer is inevitably smaller than the thickness of the lower magnetic layer to be buried because of the buried formation. In addition, since it is difficult to process a minute and deep hole for burying and forming the spacer, the interval for preventing the leakage magnetic flux cannot be made too large, and as a result, a significant improvement effect cannot be expected. That is, as shown in FIG. 9B, since the thickness (depth) Δd of the spacer 900 is small, the magnetic flux leaks and passes through the spacer 900. Therefore, the magnetic flux to be emitted to the tip of the gap 70 decreases. In the figure, L indicates a life dimension (gap depth).
[0012]
The present invention focuses on these points, and suppresses the leakage of magnetic flux near the tip of the magnetic gap, effectively introduces and concentrates the magnetic flux at the tip of the gap, and is suitable for high-density recording. It is an object of the present invention to provide a magnetic head and a method for manufacturing the same.
[0013]
[Means and Actions for Solving the Problems]
In order to solve the above problems, the present invention has at least upper and lower cores, a front intermediate core and a rear intermediate core formed between the upper and lower cores, each layer constituting a magnetic circuit is formed flat , A thin-film magnetic head in which a magnetic gap is formed in one of the stacked portions of the upper and lower cores and the intermediate core, wherein the magnetic gap is formed in a central portion of the stacked portion of the front intermediate core, and stacking unit parts intermediate core, said side is the rear than the position of the gap depth 0 of the front intermediate core, toward the magnetic gap from the upper and lower core, symmetrically with respect to the magnetic gap, and stepwise width A thin-film magnetic head comprising a plurality of intermediate cores having a reduced width . For this reason, particularly suppressed leakage flux gap near the time of recording, it is possible to introduce concentrate effectively gap tip flux. The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.
[0014]
Description of the preferred embodiment
While the present invention is capable of numerous embodiments, a suitable number of embodiments are shown and described in detail.
[0015]
<Example 1>
First, a first embodiment will be described with reference to FIGS. The thin film magnetic head according to the first embodiment has a structure in which four intermediate cores are formed in a step-like manner between upper and lower cores arranged so as to sandwich a winding portion as shown in a cross section in FIG. Has become.
First, a method of manufacturing the thin-film magnetic head according to the first embodiment will be sequentially described with reference to FIGS. An insulating layer 52 and a lower core 54 are formed to a predetermined thickness on the substrate 50, and the surface is flattened (see FIG. 2A). This step is specifically shown in FIGS. 4A to 4D or FIGS.
[0016]
Starting from the first method, a soft magnetic film 53 is formed on a substrate 50 (see FIG. 4A), and this is used as a lower core 54 of a core-shaped pattern by etching or the like (see FIG. 4B )reference). Next, an insulating film 51 is formed to a predetermined thickness on the main surface of the substrate 50 including the lower core 54 (see FIG. 4C), and the insulating film 51 deposited on the core pattern 54 is removed by polishing. The surface is flattened (see FIG. 4D). Thus, the insulating film 52 and the lower core 54 are obtained.
[0017]
Next, a second method will be described. An insulating film 51 is formed on a substrate 50 (see FIG. 4 (X)), and a core-shaped groove 55 is formed therein (see FIG. 4 (Y)). . Then, a soft magnetic film 53 is formed on the main surface of the substrate 50 including the groove 55 (see FIG. 4 (Z)), and the soft magnetic film 53 deposited on the insulating film 52 is removed by polishing to remove the surface. Flatten (see FIG. 4D). Thus, the soft magnetic film 53 remaining in the groove 55 is used as the lower core 54.
[0018]
Next, returning to FIG. 2, a front intermediate core 56, a rear intermediate core 58, and an insulating film 60 are formed on the insulating film 52 and the lower core 54 in the same manner as in FIG. (B)). Further, by repeating the same method, the intermediate cores 62 and 58A and the insulating film 60A are formed as shown in FIG. Among them, the front intermediate core 62 has a smaller width in the gap depth direction than the lower front intermediate core 56, and has a step-like shape as a whole. The intermediate core 58A is continuously integrated with the intermediate core 58, and the insulating film 60A is continuously integrated with the insulating film 60. Therefore, both will be denoted by the same reference numerals.
[0019]
By using such a method of embedding and polishing, it is possible to easily widen the magnetic core interval (thickness) for suppressing the leakage magnetic flux without deteriorating the characteristics of the magnetic film.
[0020]
Next, a number of grooves 64 for embedding the coil are formed in the insulating film 60 by etching (see FIG. 3D). A metal material such as Cu is buried in the groove 64 formed as described above, and the main surface is polished and removed so as to be flat, thereby forming the coil 68 (see FIG. 2E).
[0021]
Next, a gap material 70 made of an insulating material is formed on the main surface of the substrate 50 except for a region where the rear intermediate core is formed by a predetermined thickness (see FIG. 2F). Further, the front intermediate cores 71 and 72, the rear intermediate core 74, and the insulating film 76 are formed on the main surface in the same manner as in FIG. 2B (see FIG. 3G). The front intermediate core 71 has a smaller width in the gap depth direction than the front intermediate core 72, and has a step-like shape as a whole. In this case as well, the rear intermediate core 74 and the insulating film 76 have two layers, but since both are continuously integrated, they are represented by the same reference numerals. After that, a second-layer coil 78 is formed in the insulating film 76 in the same manner as in FIGS. 2D and 2E (see FIG. 3H).
[0022]
Next, an insulating film 80 is formed to a predetermined thickness except for a region where the front intermediate core 72 and the rear intermediate core 74 are formed, and an upper core 82 is formed in the same manner as in FIG. FIG. 3 (I)). Further, a lead wire 84 connected to the coil 78 is formed on the insulating film 80 (see FIG. 3J). Then, a plurality of chips of each magnetic head element formed on the substrate are cut, and the medium facing surface is processed by a method such as polishing so as to have a predetermined gap depth (lifetime dimension). 1 is obtained.
[0023]
Next, the operation of the thin-film magnetic head manufactured as described above will be described. As shown in FIG. 1A, upper and lower cores 54 and 82 are arranged so as to sandwich the coils 68 and 78, and the front portions of the upper and lower cores are four-layer front intermediate cores 56, 62, 71 and 72. Are joined. The rear portions of the upper and lower cores are joined by two layers of rear intermediate cores 58 and 74, respectively.
[0024]
The front intermediate cores 56, 62, 71, 72 from the magnetic gap 70 to the upper and lower cores 54, 82 are stepped at the rear of the position where the gap depth L = 0 (see FIG. 3B). It has become. With such a shape, the thickness Δd of the magnetic leakage portion can be increased as shown in the enlarged view of FIG. 2B, and the intermediate cores 56, 62, 71, 72 are wound around the upper and lower cores 54, 82. The structure becomes gradually closer to the magnetic gap 70 from the line portion (magnetic field generating portion). In other words, the width is narrowest near the magnetic gap, and the width increases as the distance from the gap increases. For this reason, the magnetic flux generated by energizing the coils 68 and 78 is as shown by the broken line in FIG. 1B, and the leakage magnetic flux particularly in the vicinity of the magnetic gap 70 generated at the time of recording can be suppressed well, and the magnetic flux can be reduced. It is possible to effectively guide and concentrate on the tip of the gap.
[0025]
<Example 2>
Next, a second embodiment will be described with reference to FIG. Note that the same reference numerals are used for components corresponding to the above-described embodiments (the same applies to the following embodiments). In the embodiment shown in FIG. 5A, the front portions of the upper and lower cores 54, 82 are joined by front intermediate cores 72, 100, and the front intermediate cores 72, 100 are stepped. A magnetic gap 70 is provided between the front intermediate core 100 and the lower core 54.
[0026]
On the other hand, in the embodiment shown in FIG. 3B, the front portions of the upper and lower cores 54, 82 are joined by front intermediate cores 56, 102, and the front intermediate cores 56, 102 are stepped. I have. A magnetic gap 70 is provided between the front intermediate core 102 and the upper core 82.
[0027]
In any of the examples, the magnetic path has a stepped shape in which the magnetic path becomes narrower toward the magnetic gap 70, and the magnetic flux can be concentrated on the magnetic gap by securing the magnitude of Δd as in the above-described embodiment.
[0028]
<Example 3>
Next, a third embodiment will be described with reference to FIG. In the third embodiment, the intermediate core and the coil have a three-layer structure, and include the coils 68, 78, and 110. In the embodiment shown in FIG. 6A, the upper and lower cores 54, 82 are joined by three layers of front intermediate cores 56, 72, 112 and three layers of rear intermediate cores 58, 74, 114. . Among them, the front intermediate cores 56, 72, 112 are stepped, and a magnetic gap 70 is provided between the front intermediate cores 72 and 112. The magnetic gap 70 may be formed between the front intermediate cores 56 and 112.
[0029]
In the embodiment shown in FIG. 7B, the upper and lower cores 54, 82 are joined by three layers of front intermediate cores 56, 120, 122 and three layers of rear intermediate cores 58, 74, 114. Of these, the front intermediate cores 56, 120, and 122 are stepped, and the magnetic gap 70 is provided between the upper core 82 and the front intermediate core 122. The front intermediate cores 56, 120, 122 may have the step shape reversed, and the magnetic gap 70 may be formed between the lower core 54 and the front intermediate core 56.
[0030]
Also in this embodiment, the front intermediate core has a stepped shape in which the magnetic path narrows toward the magnetic gap 70, and the magnetic flux can be concentrated on the magnetic gap as in the previous embodiment.
[0031]
<Example 4>
Next, a fourth embodiment will be described with reference to FIG. In the fourth embodiment, the intermediate core and the coil have a four-layer structure, and include coils 68, 78, 110, and 130. The upper and lower cores 54, 82 are joined by four layers of front intermediate cores 56, 72, 132, 134 and four layers of rear intermediate cores 58, 74, 136, 138. Of these, the front intermediate cores 56, 72, 132, 134 are stepped, and a magnetic gap 70 is provided between the front intermediate cores 132 and 134. The magnetic gap 70 may be formed between the front intermediate cores 56 and 132 or between 72 and 134, and each intermediate core may be formed so that the magnetic path becomes narrower toward it.
[0032]
According to this embodiment, since Δd can be considerably increased as compared with the above-described embodiment, there is an advantage that the effect of suppressing the leakage magnetic flux is increased.
[0033]
<Other embodiments>
The present invention can be variously modified based on the above disclosure. For example, the number of stacked front intermediate cores and the size of the stepped shape may be appropriately set in addition to the above-described embodiment. Also, the number of stacked front intermediate cores and the number of coil stages need not match, and may be set as appropriate. The shapes and dimensions of the other parts may be appropriately changed as needed as long as the same operation is achieved.
[0034]
【The invention's effect】
As described above, according to the present invention, the magnetic gap is formed at the center of the laminated portion of the front intermediate core, and the laminated portion of the front intermediate core has a gap depth of 0 of the intermediate core. Since the rear side of the position is composed of a plurality of intermediate cores whose widths are symmetrically and stepwise reduced with respect to the magnetic gap from the upper and lower cores toward the magnetic gap, the leakage flux near the magnetic gap Is minimized, and the magnetic flux can be effectively introduced and concentrated at the tip of the magnetic gap.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part showing a first embodiment of a thin-film magnetic head according to the present invention.
FIG. 2 is an explanatory view showing a manufacturing process of the first embodiment.
FIG. 3 is an explanatory view showing a manufacturing process of the first embodiment.
FIG. 4 is an explanatory diagram showing a part of the manufacturing process of the first embodiment in detail.
FIG. 5 is a sectional view of a main part showing a second embodiment of the present invention.
FIG. 6 is a sectional view of a main part showing a third embodiment of the present invention.
FIG. 7 is a sectional view of a main part showing a fourth embodiment of the present invention.
FIG. 8 is a sectional view of a main part showing a conventional thin film magnetic head.
FIG. 9 is a sectional view of a main part showing a conventional thin film magnetic head.
[Explanation of symbols]
50 ... substrate 52,60,76,80 ... insulating film 54 ... lower core 56,62,71,72,100,102,112,120,122,132,134 ... front middle core 58,74,114,136 , 138, rear intermediate core 64, grooves 68, 78, 110, 130, coil 70, magnetic gap 82, upper core Δd, thickness of magnetic leakage part

Claims (1)

At least the upper and lower cores, a front intermediate core and a rear intermediate core formed between the upper and lower cores, each layer constituting a magnetic circuit is formed flat, and any one of the stacked portions of the upper and lower cores and the intermediate core A thin film magnetic head in which a magnetic gap is formed,
The magnetic gap is formed at a central portion of the laminated portion of the front intermediate core, and the laminated portion of the front intermediate core is arranged such that the rear side of the front intermediate core at a gap depth of 0 is the vertical direction. towards the core to the magnetic gap, symmetrical, and thin-film magnetic head is characterized by being composed of a plurality of intermediate core which is narrowed stepwise width with respect to the magnetic gap.

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