JPH05128441A - Thin-film head for perpendicular magnetic recording - Google Patents

Abstract

PURPOSE:To provide the thin-film head for perpendicular magnetic recording which is improved in performance by enhancing the magnetic characteristics of cores and can deal with a trend toward higher densities. CONSTITUTION:The intermediate core 28 having the lower core 24, the upper core 30 and a coil 34 is formed of magnetic materials provided in insulating layers 42, 44, 46 and the surfaces of the respective layers including the cores 24, 28, 30 are subjected to a flattening treatment to eliminate level differences. A main magnetic pole 26 is formed on the surfaces of any layer of the respective cores and at least one of the other core is formed as an auxiliary magnetic pole 32. As a result, the level differences on the surfaces of the respective layers are eliminated and the photolithography and etching with high accuracy are enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film head for perpendicular magnetic recording, and more particularly to a thin film head having improved magnetic characteristics and suitable for high density recording.

[0002]

2. Description of the Related Art Generally, as a typical thin film head for perpendicular magnetic recording, a structure having a structure as shown in FIGS. 11A and 11B is known. This type of thin film head is formed by sequentially stacking magnetic layers and conductor layers by a thin film forming process, processing this into a core shape, coil shape, etc. by photolithography technology and etching, and then stacking these and an insulating layer. By forming a magnetic circuit.

That is, first, a magnetic film is formed on the substrate 2 and subjected to photolithography and etching to form the main magnetic pole 4. After the main magnetic pole 4 is formed in this way, a magnetic film is further formed on the main magnetic pole 4, and the lower core 6 is formed by subjecting the magnetic film to photolithography and etching.
Furthermore, the insulating layer 8 is formed over the entire surface, and unnecessary portions are removed by photolithography and etching. Then, a conductor layer is formed on the insulating layer 8, and the coil 10 is formed by subjecting the conductor layer to photolithography and etching to form a coil shape. Furthermore,
An insulating layer 12 is formed on the coil 10 and unnecessary portions are removed by photolithography and etching. Then, a magnetic layer is entirely formed on the insulating layer 12, an upper core 14 is formed on the magnetic layer by photolithography and etching, and the tip portion of the upper core 14 serves as the auxiliary magnetic pole 20. Then, a through hole (not shown) is formed in the insulating layer 12 on the coil 10 and the lead wire 16 is arranged therein. Furthermore, a suitable protective layer 1 is provided over the entire surface.
8 is formed.

[0004]

By the way, in such a forming method, as is clear from FIG. 11, the shapes of the cores 6 and 14 and the coil 10 are processed by etching or the like, and these are sequentially stacked. As a result, a step S occurs on the surface, and this step tends to increase as the number of layers increases. Normally, each core 6 and 14 is formed to have a thickness of about 5 μm, and the coil 10 is formed to have a thickness of about 3 μm, and the coils are multilayered in order to increase the number of coil turns. Therefore, the step S has a height of 10 μm or more immediately before the formation of the upper core 14. Normally, the magnetic layer for the core is formed by sputtering vapor deposition, vapor deposition, plating, or the like, but in such a magnetic film forming method, the magnetic characteristics at the step S are extremely deteriorated, and therefore the step S Upper core 14 formed on the large
However, there was a problem that the magnetic properties of were deteriorated considerably.

Further, in the photolithography technique and the etching process for fine processing, pattern processing of 1 μm or less is possible recently in a state where the processed surface is flat. When there is a step, the resolution of photolithography is extremely lowered, and the resolution is degraded to the extent of the step. For example, in a thin film head having a step difference of 5 to 10 μm, the minimum line width of the coil 10 is 5 to 10 μm, and the coil pitch is limited to about 10 μm. The coil pitch is 10 μm as described above because the coil layer has 10 to 20 turns.
If it is m, the length of the core becomes as long as 100 to 200 μm, and since the thickness of the core is as thin as several μm, the magnetic resistance of the core as a whole becomes high, and the performance as a magnetic head becomes worse. Will end up. Moreover, since the auxiliary magnetic pole is composed of only the upper core 16, the exposed area of the auxiliary magnetic pole with respect to the recording medium is small, which also deteriorates the performance of the magnetic head.

The shape of the tip of the magnetic head is shown in FIG.
As also shown in FIG. 3, since the auxiliary magnetic pole 20 formed of the upper core 14 and the main magnetic pole 4 face each other, the swelling of the frequency characteristics and the phase shift due to the pseudo gap occur, and good performance cannot be obtained. As described above, in the conventional method of forming a thin film head, it is difficult to form a magnetic head that has poor magnetic characteristics of the core, poor performance as a magnetic head, and high density magnetic recording. It was The present invention is
It was devised to pay attention to the above problems and effectively solve them. An object of the present invention is to provide a thin film head for perpendicular magnetic recording capable of improving the magnetic characteristics of the core to improve the performance and capable of dealing with higher density.

[0007]

In order to solve the above-mentioned problems, the present invention provides a lower core, an upper core, and an intermediate core having a coil wound while connecting the upper core and the lower core. In a thin film head for perpendicular magnetic recording having a three-layer structure, the lower core, the upper core, and the intermediate core are formed of a magnetic material provided in an insulating layer, and the connecting surface of each core and the insulating layer of each layer are formed. Form the surface including the
A main magnetic pole for magnetic recording or reproduction is formed on the surface of any layer of each core, and at least one of the cores is configured as an auxiliary magnetic pole.

[0008]

Since the present invention is configured as described above, the upper and lower cores are embedded in the insulating layer and the surface layer is flattened, and the upper and lower cores and the intermediate core sandwiched therebetween form a magnetic circuit. Then, the main magnetic pole is formed on the surface of any layer of each core, and at least one of the cores is used as an auxiliary magnetic pole. As a result, the core is always formed on a flat surface, so that high-precision photolithography and etching can be performed on the upper layer. Therefore, since the magnetic film can be formed on the flat surface having no step, the core having good magnetic characteristics can be formed. Further, since there is no step, it is possible to etch a thick core, and by thickening the core itself, the magnetic resistance of the core can be reduced and the area of the auxiliary magnetic pole with respect to the recording medium can be increased.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the thin film head for perpendicular magnetic recording according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a perspective view showing a thin film head for perpendicular magnetic recording according to the present invention,
2 is a view taken along the line AA in FIG. 1, and FIGS. 3 and 4 are explanatory views for explaining a surface flattening process used when forming a thin film head for perpendicular magnetic recording. As shown in the figure, the lower layer of the perpendicular magnetic recording thin film head 22 has a lower core 24 made of a magnetic material and having a predetermined thickness and a predetermined length. The main magnetic pole 26 is formed. The tip of the main magnetic pole 26 is provided so as to slightly extend from the tip of the lower core 24 by a predetermined length.

From the rear end of the lower core 24,
An intermediate core 28, which is made upright and made of a magnetic material, is provided in the intermediate layer. An upper core 30 also made of a magnetic material is formed in the upper layer of the intermediate layer by connecting one end to the intermediate core 28. Therefore, the lower core 2
4 and the upper core 30 are magnetically connected via the intermediate core 28. The upper core 30 is bifurcated so as to sandwich the lower core 24 from the horizontal direction, and the tip of the upper core 30 is bent downward to extend to the intermediate layer and the lower layer. The part is the auxiliary magnetic pole 32
Is configured as. The tip of the auxiliary magnetic pole 32 and the tip of the main magnetic pole 26 are aligned in the vertical plane. A coil 34 made of a conductor such as copper is wound around the intermediate core 28 in the horizontal direction so as to be wound a plurality of times in the horizontal direction. This lead wire 3 has been pulled out.
6 and the other lead wire 38 located on the same plane as the coil 34 can extract or supply a signal. Insulating layers 40, 42 and 44 made of an insulating material such as SiO ₂ are formed between the upper and lower cores 24 and 30, the intermediate core 28 and the coil 34.

A method of forming each core in the above structure will be described with reference to FIG. First, as shown in FIG. 3 (A), a soft magnetic thin film 40 made of, for example, permalloy is formed on the substrate 2 or on the surface of the lower layer or the intermediate layer on which the core is formed and flattened by sputtering deposition or the like. 10 μm
It is deposited and formed with a thickness of. Next, as shown in FIG. 3B, the magnetic film 40 is processed into a corresponding core shape by performing photolithography or etching to form the core 24,
28 and 30 are formed. Next, as shown in FIG. 3C, when the cores 24, 28, 30 are formed, insulating films 42, 44 made of SiO ₂ , TiO ₂ , Al ₂ O _3, etc. are formed over the entire surface including the core surfaces. , 46 is deposited thicker than the thickness of the core to form an insulating layer. After that, by mechanically polishing the entire surface as shown in FIG.
The entire surface is flattened, thereby forming the corresponding core. The method of forming this core is as follows:
The present invention can be applied to the case of forming either 8 or the upper core 30.

Further, the method shown in FIG. 4 may be adopted instead of the method of forming the core shown in FIG. First, as shown in FIG. 4 (A), SiO ₂ , TiO ₂ , A is formed on the substrate 2 or on the surface of the lower layer or the intermediate layer on which the core is formed and flattened.
An insulating film 42 such as l ₂ O ₃ is deposited and formed to a thickness of 4 to 10 μm. Then, as shown in FIG.
The core-shaped core groove 48 is formed by subjecting 2 to photolithography or etching. Then, FIG.
As shown in (C), a soft magnetic thin film 40 such as permalloy is formed over the entire surface to completely fill the inside of the core groove 48. Then, as shown in FIG. 4D, the entire surface is mechanically polished to planarize the surface, and the cores 24, 28, 30 and the insulating layers 42, 44, 46 are formed.

By such a method, each core 24, 2
By forming 8 and 30, it becomes possible to always form a further upper layer on a flat surface. A coil 34 is embedded around the intermediate core 28 of the intermediate layer by winding the intermediate core 28, which is formed by the molding method shown in FIG. That is, first, as shown in FIG. 5A, a coil-shaped coil groove 50 is formed in the insulating layer 44 in which the intermediate core 28 is embedded by photolithography or etching. Next, as shown in FIG. 5B, a conductor film 52 is formed by depositing a conductor such as copper on the entire surface, and the coil groove 50 is completely filled. After that, as shown in FIG. 5C, an extra conductor film 52 on the insulating layer 44 and on the coil groove is formed.
Are removed by, for example, mechanical polishing to planarize the entire surface, thereby forming the coil 34. The intermediate layer forming this coil can be formed into multiple layers by repeating the same process, whereby the number of turns can be increased and the facing area of the auxiliary magnetic pole facing the recording medium can be increased, and the thin film head with higher sensitivity can be obtained. Can be formed.

Next, a method for forming a thin film head having the structure shown in FIGS. 1 and 2 by using the method shown in FIGS. 3 to 5 will be described with reference to FIGS. 6 to 10. In this method, the coil has one layer, and the core is formed by a method in which an insulating layer is formed afterward as shown in FIG. First, as shown in FIGS. 6A and 6B, on the surface of the substrate 2, permalloy, sendust, amorphous magnetic material,
A magnetic material made of Fe nitride or the like is deposited and formed to a thickness of 1 to 10 μm, this magnetic layer is etched into a core shape, and thereafter, SiO ₂ , Al ₂ O ₃ , and TiO ₂ are formed to a thickness equal to or larger than the core thickness.
Forming an insulating film of Then, the entire surface is mechanically polished to form a flat surface, and the lower core 24
To form. At this time, the lower layer 32A of the auxiliary pole is also formed on both sides of the tip of the lower core 24.

Next, as shown in FIGS. 7A and 7B, permalloy, sendust, amorphous magnetic material,
A magnetic substance such as Fe nitride is deposited and formed over the entire surface to a thickness of 0.1 to 1 μm, and then the magnetic substance is subjected to photolithography and etching treatment to be processed into a main pole shape, and is formed on the lower core 24. The main magnetic pole 26 is formed. Then, FIG.
As shown in FIGS. 8A and 8B, the intermediate core 28 and the intermediate layer 32B of the auxiliary magnetic pole 32 are formed by the same method as that for forming the lower core 24. After that, FIG. 9 (A)
And as shown in FIG. 9B, a coil-shaped coil groove is formed in the intermediate insulating layer 44 by using the method shown in FIG. 5, and a conductor such as copper is embedded in the groove to form a surface. The whole is flattened to form a coil 34 wound around the intermediate core 28.

Next, as shown in FIGS. 10A and 10B, the upper core 30 is formed by using the same method as that for forming the lower core 24 described above, and the upper insulating layer 4 is formed.
A through hole 56 penetrating 6 and extending to the base end portion of the coil 34 located in the intermediate layer is formed by etching;
The lead wire 36 is connected to this. After that, an appropriate protective layer is formed on the entire surface and a predetermined processing is performed to finish the thin film head.

Next, the operation of the thin film head having the above structure will be described. First, a recording medium (not shown)
For recording and reproducing with respect to, the magnetic circuit is formed by a closed loop formed by the recording medium located at the tip of the thin film head, the main pole, the lower core 24, the intermediate core 28, and the upper core 30 in this order, and the magnetic signal is Recording or reproduction is performed via the coil 34 wound around the intermediate core 24. In the conventional thin film head, a large step is generated on the laminated surface due to the coil shape, which makes it difficult to perform high-precision lithography and etching, and to form a coil with a narrow pitch such as a few μm width. Difficult and again
It was also difficult to form a thick core. Further, the magnetic film formed on the step has poor magnetic characteristics and also has poor performance as a magnetic head. In addition, since the area of the auxiliary magnetic pole facing the recording medium is small and the efficiency is lowered, the sensitivity is poor.

On the other hand, in the present embodiment, a magnetic circuit is formed by at least three layers of the upper core 30, the lower core 24, and the intermediate core 28 that magnetically connects these to form the intermediate core 28. A coil 34 is formed on the same layer to form a thin film head, and each core 24, 28, 3 is formed.
0, the coil 34 is formed in the insulating layers 42, 44 and 46, and the surface of each layer is flattened by flattening polishing so that it is always flat when the next layer is deposited. Therefore, highly accurate photolithography and etching can be performed, the coils 34 with a fine pitch can be formed, and a large number of coil turns can be obtained with a small magnetic circuit. Further, since the magnetic layer is always formed on a flat surface, the step which has been conventionally generated does not occur, and therefore, the magnetic characteristics are not deteriorated and the thin film with good efficiency is obtained. It becomes possible to form a head.

Further, the auxiliary magnetic pole 32 located at the tip of the upper core 30 can be formed over all of the lower layer, the intermediate layer and the upper layer, so that the area where it faces the recording medium is increased. Therefore, the recording / reproducing efficiency can be greatly improved. Further, the auxiliary magnetic pole 3
Since No. 2 is located on both sides of the main magnetic pole 26, deterioration of frequency characteristics due to a pseudo gap, phase shift, etc. are eliminated, and it is possible to provide a high-performance thin film head for perpendicular magnetic recording. The material of the magnetic body and the material of the conductor are not limited to the materials mentioned in the above-mentioned embodiment, and other materials may be used. Further, the flattening treatment of each layer is not limited to mechanical polishing, and it goes without saying that the flattening treatment may be performed by another method such as chemical treatment or physical treatment.

[0020]

As described above, according to the present invention, the following excellent operational effects can be exhibited. High-precision photolithography and etching are possible, and a large number of coils with a fine pitch can be formed. Further, since it is possible to prevent a step from being formed in the magnetic film or the like, it is possible to provide a thin film head with little deterioration in magnetic characteristics and excellent reproduction / recording efficiency in combination with the reason described above. Further, when the auxiliary magnetic pole is widened to increase the surface facing the recording medium, the reproducing / recording efficiency can be further improved. Further, when the auxiliary magnetic poles are located on both sides of the main magnetic pole, it is possible to suppress the occurrence of pseudo gaps and prevent deterioration of frequency characteristics, phase shift, and the like.

[Brief description of drawings]

FIG. 1 is a perspective view showing a thin film head for perpendicular magnetic recording according to the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is an explanatory diagram for explaining a surface flattening process used when forming a thin film head.

FIG. 4 is an explanatory diagram for explaining a surface flattening process used when forming a thin film head.

FIG. 5 is an explanatory diagram for explaining a method of forming a coil.

FIG. 6 is a process drawing of forming a thin film head.

FIG. 7 is a process drawing of forming a thin film head.

FIG. 8 is a process drawing of forming a thin film head.

FIG. 9 is a process drawing of forming a thin film head.

FIG. 10 is a process drawing of forming a thin film head.

FIG. 11 is a configuration diagram for explaining a conventional thin film head for perpendicular magnetic recording.

12 is a diagram showing a relationship between a main magnetic pole and an auxiliary magnetic pole of the thin film head shown in FIG.

[Explanation of symbols]

2 ... Substrate, 4, 26 ... Main magnetic pole, 6, 24 ... Lower core, 8,
12, 42, 44, 46 ... Insulating layer, 10, 34 ... Coil, 14, 30 ... Upper core, 20, 32 ... Auxiliary magnetic pole, 1
6, 36, 38 ... Lead wire, 22 ... Perpendicular magnetic recording thin film head, S ... Step.

Claims (1)

[Claims] 1. A perpendicular magnetic recording thin film head having a three-layer structure having a lower core, an upper core, and an intermediate core having a coil wound while connecting the upper core and the lower core. The core, the upper core, and the intermediate core are formed of a magnetic material provided in an insulating layer, and the connecting surface of each core and the surface of each layer including the insulating layer are formed to be substantially flat, and one of the layers of each core is formed. A thin film head for perpendicular magnetic recording, characterized in that a main magnetic pole for magnetic recording or reproduction is formed on the surface of, and at least one of the cores is configured as an auxiliary magnetic pole.