JPH02232805A - Manufacture of composite magnetic head - Google Patents

Abstract

PURPOSE:To obtain the almost sine wave-shaped surface of a core material by arranging a photomask, which has plural slits, in parallel with a photoregist on the core material with providing a gap between the photomask and photoregist and executing exposure. CONSTITUTION:A photoregist 38 is applied to the surface of a core material 37. Next, a photomask 39 having slits 39a is arranged with providing a gap C between the mask 39 and regist 38. In such a state, when the core material is irradiated with ultraviolet beam and developed, the shape of the regist 38 is almost the sine wave. Next, etching is executed by ion beam and a groove is formed in the core material 37. Then, when a metallic magnetic film 42 is formed on a side where the groove of the core material 37 is provided, a boundary surface between the film 42 and core material is almost sine wave- shaped. After that, the surface, where the film 42 is formed, is made plane, the core material 37 is cut along a dotted line LM and a core bar 43 is formed. Finally, an winding groove is formed in the core bar 43 and the two core bars 43 are prepared and joined through a non-magnetic substance 44 so that the films 42 can be mutually faced. Thus, a magnetic head can be obtained not to generate a pseudo gap.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used in a magnetic recording/reproducing device that writes data to a magnetic recording medium and reads data from a magnetic recording medium. The present invention relates to a method of manufacturing a magnetic head in which a magnetic head is formed.

BACKGROUND ART In order to improve the image quality of VTRs and increase the capacity of external storage devices for computers, it is necessary to perform high-density recording. In order to perform this high-density recording, in recent years, efforts have been made to increase the coercive force of recording media, increase the magnetic flux density of magnetic heads, and narrow the gap. In order to increase the magnetic flux density of a magnetic head, a magnetic head has been developed in which a metal magnetic thin film with a high saturation magnetic flux density is formed on the surface facing the gap. Generally, such a magnetic head is called a composite magnetic head.

A conventional composite magnetic head will be explained below. 18th
The figure is a perspective view of a conventional composite magnetic head. 1st
In FIG. 8, numerals 1 and 2 are magnetic cores made of a metal oxide magnetic material such as ferrite, and the magnetic cores 1.2 are provided with winding grooves 1a and 2a, respectively. 3 and 4 are metal magnetic films formed on the gap-opposing surfaces of the magnetic cores 1 and 2, respectively, and the metal magnetic films 3 and 4 are made by sputtering or vapor-depositing a metal magnetic material such as sendust having a high saturation magnetic flux density. is formed by. A gap filler 5 is provided between the magnetic cores 1 and 2 and serves as a magnetic gap. A composite magnetic head with this structure has the advantage that it can magnetize a high coercive force medium and that reproduction efficiency can be improved by appropriately selecting the thickness of the metal magnetic film. However, in such a composite magnetic head, as shown in FIG.
Since the interfaces 6 and 7 between the metal magnetic films 3 and 4 are located parallel to the gap line, this operates as a pseudo gap, resulting in a decrease in the SZN ratio. Conventionally, as a countermeasure against this problem, a method has been adopted in which the interfaces 6 and 7 are tilted with respect to the gap line to suppress the spurious output by the azimuth effect. Gear up lie.
As the inclination angle, that is, the azimuth angle of the interfaces 6 and 7 becomes larger with respect to the magnetic head, the effect becomes larger.
It is considered that 30° is sufficient. A conventional example that utilizes this azimuth effect will be explained.

FIG. 19 is a perspective view showing a conventional composite magnetic head. In FIG. 19, 8 and 9 are magnetic cores, and magnetic core 8
has an inclined surface 8a. 8b, a metal magnetic film 10 is formed on the inclined surface 8a, and glass 11 is filled thereon. Further, the inclined surface 8b is filled with glass 11 so as to be in contact with the magnetic core 8 without providing a metal magnetic film.

At this time, the glass 11 and the metal magnetic film 10 are processed so that they are in the same plane on the surfaces facing the gap. Further, the magnetic core 8 is provided with a winding groove 8c. Similarly, the magnetic core 9 forms inclined surfaces 9a*9b, and the inclined surfaces 9
A metal magnetic film 12 is formed on the surface a, and glass 13 is filled thereon. The inclined surface 9b is filled with glass 13 so as to be in contact with the magnetic core 9 without providing a metal magnetic film.

The magnetic cores 8 and 9 configured in this way are connected to glasses 11 and 13.
and metal magnetic films 10 and 12 are joined via the nonmagnetic material 14 so as to face each other. Although this type has a large effect of suppressing the pseudo gap effect, it has a structure in which the substrate on which the metal magnetic film is deposited is tilted, so it has many problems such as being complicated in construction method and weak in strength.

FIG. 20 is a perspective view showing another conventional composite magnetic head. In this conventional example, the interface between the magnetic cores 15, 16 and the metal magnetic film 17.18 has a substantially semicircular arc shape. 18 are joined so that they face each other. Next, a method of forming the interface between the metal magnetic films 17, 18 and the magnetic core 15, 16 into a substantially semicircular arc shape will be described. First, as shown in FIG. 21, photoresists 21 are formed at equal intervals on a core material 20 that will become a magnetic core. Next, when photochemical etching is performed, as shown in FIG. 22, the core material 20 is gradually etched from the portion where the photoresist 21 is not attached. Next, as shown in FIG. 23, the entire portion of the photoresist 21 to which the core material 20 is attached is finally etched away, and the photoresist 21 is peeled off from the core material 20. In this way, in the conventional example shown in Fig. 20, since the unevenness is directly formed on the substrate surface, there is no need to shave the substrate diagonally, and the construction method is simpler than in Fig. 19, but the etching interface formed is , as shown in Figure 20, there are few parts with a sufficient azimuth angle because it is semicircular arc-shaped,
If etching is not stopped immediately after peeling, the core material tends to become flattened gradually, and sharp edges like the P part shown in Figure 20 are likely to form, and cracks may occur in the magnetic core due to stress concentration. There were some problems.

FIG. 24 is a perspective view showing another conventional composite magnetic head. In Fig. 24, 22 and 23 are respectively magnetic cores made of single crystal ferrite, 24 and 25 are metal magnetic films,
26 is a non-magnetic material serving as a magnetic gap. In this conventional example, the interface between the magnetic core 22.23 and the metal magnetic film 24.25 has a triangular wave shape. The following metal magnetic film 24.2
A method of forming the interface between the magnetic core 22 and the magnetic core 22, 23 into a triangular wave shape will be explained using FIGS. 25 to 27.

First, as shown in FIG. 25, striped photoresist layers 28 are formed at equal intervals on a core material 27 made of single crystal ferrite. When etching is performed thereafter, the cross section of the core material 27 is etched into a triangular shape as shown in FIG. 26 due to the difference in etching speed depending on the crystal orientation. As the etching continues, the photoresist 28 peels off from the core material 27, forming a triangular wave-like interface, as shown in FIG. 27, and a metal magnetic film is formed on this surface. In the conventional example shown in FIG. 24, the tips and bottoms of the triangular waves are sharp, causing stress concentration in these areas and causing cracks. Furthermore, the substrate material is limited to single crystal. I had the same problem.

Therefore, when considering the above contents comprehensively, a composite magnetic head that can be expected to have a sufficient azimuth effect and has an interface shape that can prevent stress concentration is defined as the shape of the interface between the magnetic core and the metal magnetic film. A sinusoidal waveform is considered to be the most likely. When manufacturing a composite magnetic head, in order to satisfy both strength and suppression of pseudo-gap effects, it is necessary to make the interface between the magnetic core and the metal magnetic film approximately sinusoidal as described above. Ru. However, Figures 20 and 24
Chemical etching, as in the conventional example shown in the figure, has problems such as the tip being sharp and cracks likely to occur at that point. Therefore, as another etching method, a highly anisotropic etching method such as ion milling can be considered, and a feature of this etching method is that the final etched shape easily inherits the shape of the mask pattern.

In other words, if it is possible to achieve a mask pattern shape that is close to the desired interface shape, that is, a substantially sinusoidal wave shape, the same interface shape can be easily obtained after etching.

Problems to be Solved by the Invention However, in the conventional exposure method, as shown in FIG.
1 is in contact with the light, and the mask pattern formed thereby tends to have a trapezoidal shape as shown in FIG. 29, which is a drawback. When physical etching such as ion milling was performed in this state, an angular shape was formed at the interface of the core material 29.

Therefore, there was a problem in that the interface between the magnetic core and the metal magnetic film could not be formed into a substantially sinusoidal shape.

The present invention solves the above-mentioned conventional problems, and allows a substantially sinusoidal mask pattern to be formed on the core material that becomes the magnetic core, thereby making the interface between the magnetic core and the metal magnetic film substantially sinusoidal. The object of the present invention is to provide a method for manufacturing a composite magnetic head which can obtain a sufficient azimuth effect and has excellent mechanical strength without cracking or the like.

Means for Solving the Problem To achieve this objective, after coating the photoresist on the core material, a photomask with a plurality of slits is placed parallel to the photoresist with a gap between the photoresist and the photoresist. The core material is physically etched through the photoresist by irradiating the photoresist with light through a photomask and developing it.

Effect: With this configuration, light is irradiated onto the photoresist through multiple slits provided in the photomask, so the intensity distribution of the light hitting the photoresist becomes wavy due to the phenomenon of light diffraction, resulting in physical etching. As a result, the surface of the core material becomes approximately sinusoidal.

Embodiment FIG. 1 is a perspective view showing a composite magnetic head manufactured using a method for manufacturing a composite magnetic head according to an embodiment of the present invention. In FIG. 1, 32 and 33 are magnetic cores made of oxide magnetic material such as ferrite, and the magnetic cores 32 and 33 are provided with winding grooves 32a and 33a, respectively. 34.35 are magnetic cores 32.33 respectively
The metal magnetic films 34 and 35 are made of a material such as sendust.

The magnetic cores 32 and 33 are non-magnetic materials 36 that serve as magnetic gaps.
are connected via. The magnetic cores 32 and 33 are joined to each other so that the metal magnetic films 34 and 35 face each other with a nonmagnetic material 36 in between. The shape of each interface between the magnetic core 32.33 and the metal magnetic film 34.35 is substantially sinusoidal. Further, a glass 100 is provided across the magnetic cores 32, 33 in order to increase the adhesive strength of the magnetic cores 32, 33.

A method of manufacturing a composite magnetic head according to an embodiment of the present invention will be described below.

First, as shown in FIG. 2, a plate-shaped core material 37 made of an oxide magnetic material is prepared. This core material 37 is provided with a plurality of grooves 37a. In this example, two grooves 37a were formed. A photoresist 38 is formed on the surface of the core material 37 on the side where the groove 37a is provided so that the film thickness B becomes 8 μm.

This situation is shown in FIG. Figure 3 is the dotted line Y shown in Figure 2.
It is a sectional view taken along Z. Next, as shown in FIG. 4, a photomask 39 with slits is placed on the photoresist 3.
Place it so that it is parallel to the surface of 8.

Furthermore, the gap C between the surface of the photoresist 38 and the surface of the photomask 39 on the photoresist 38 side is set to 25 μm. At this time, the slit 39a of the photomask 39
The width D of is 10 μm, and the distance E between adjacent slits 39a is 10 μm. In this state, ultraviolet rays are irradiated from above the photomask 39, and then the photoresist 38
When the photoresist 38 is washed away with a developer, the shape of the photoresist 38 becomes approximately sinusoidal as shown in FIG. FIG. 5 is a sectional view taken along the dotted line YZ shown in FIG. This is because the shape of the photoresist 38 causes the ultraviolet rays to be diffracted by the slits 39a provided in the photomask 39, and the intensity distribution of the ultraviolet rays irradiated to the photoresist 38 becomes wavy, as shown in FIG. Conceivable. Figure 4 shows photoresist 3 based on computer simulation.
8 shows the intensity distribution of ultraviolet rays irradiated. In FIG. 6, AI, A2, and A3 are locations where the intensity of ultraviolet rays is maximum, and these positions correspond exactly to the center of the slit 39a. When the intensity of the ultraviolet rays irradiated onto the photoresist 38 becomes wavy in this way, the ultraviolet rays reach the deep part of the photoresist 38 where the intensity of the ultraviolet rays is strong.
The part where it becomes soluble becomes deeper. Further, in areas where the intensity of the ultraviolet rays is weak, the ultraviolet rays reach only shallow parts of the photoresist 38, and the parts where the photoresist 38 becomes soluble are shallow. Thereafter, when the photoresist 38 is washed away with a developer, a photoresist 37 having a substantially sinusoidal shape is formed. Next, the etching process will be explained. FIG. 7 is a schematic diagram showing the etching process. In Fig. 7, 40 is an ion gun that generates an ion beam, 41 is a rotating core material holder,
The rotating core material holder 41 includes a rotating plate 41a and a rotating shaft 4lb.
The rotating shaft 4ib is a motor (not shown).
It is connected to a power source such as Further, the core material 4l is attached to the rotary plate 41a. As shown in Figure 7, first the core material 3
7 is fixed to a rotating plate 41a, and the rotating plate 41a is rotated at a constant angular velocity. Next, an ion beam is emitted from the ion gun 40, and the rotating core material 7
irradiate. At this time, the rotary plate 41a is tilted and arranged so that the normal direction of the rotary plate 41a and the angle W of the ion beam incident on the rotary plate are 40 degrees. In this manner, the core material 37 is etched by the ion beam. Angle W is 40
The degree was determined from the following experiment. Approximately sinusoidal photoresists were formed on each of the four core materials, and etching was performed at angles W of 20 degrees, 30 degrees, 40 degrees, and 50 degrees. In Figures 8 to 11, the angle W is 20 degrees,
FIG. 3 is a cross-sectional view showing the cross section of the core material after etching at 30 degrees, 40 degrees, and 50 degrees. As can be seen from these figures, in this example, the shape is closest to the ideal when the angle W is 40 degrees. Next, as shown in FIG. 12, a metal magnetic film 42 is formed on the side of the core material 37 that has been etched in this manner, on which the groove 37a is provided.

Then, the surface on which the metal magnetic film 42 is formed is polished and flattened. This situation is shown in FIG. Next, the core material 37 is cut along the dotted line LM shown in FIG. 13 to form a core par 43 as shown in FIG. 14. Next, as shown in FIG. 15, a winding groove 43a is formed in the core par 43. Two such core pars 43 are prepared and joined together via a non-magnetic material 44 so that the metal magnetic films 42 face each other. At this time, glass 45 is attached to the vicinity of the metal magnetic film 42 of the two core pars 43 in order to increase the adhesive strength between the two core pars 43. This state is shown in FIG. Finally, the side that will become the medium facing surface is polished and a winding 46 is applied to produce a composite magnetic head as shown in FIG. 17.

In this example, the film thickness B of the photoresist is 8 μm,
The distance C between the photomask and photoresist is 25 μm, the slit width D of the photomask is 10 μm, and the slit interval E
was set to 10 μm, and the angle W between the incident direction of the ion beam and the normal direction of the rotary plate was set to 40 degrees, but experiments have shown that a substantially sinusoidal interface can be formed within the following ratio range.

E/D=0.5-1. O C/D=2-3 B/D=0.5-10. In this embodiment, a photoresist 38 is formed on the core material 37 so that W=25 degrees to 45 degrees or more, and parallel to the photoresist 38,
Furthermore, by covering the photomask 39 at a certain distance, exposing it to light, and developing it, a substantially sinusoidal photoresist 38 can be formed, so that when physical etching is performed, the surface of the core material 37 is approximately It becomes a sine wave. By forming the metal magnetic film 42 thereon, the interface between the metal magnetic film and the magnetic core becomes approximately sinusoidal. After this, cutting and polishing are performed to create two magnetic cores, and by joining the two magnetic cores through a non-magnetic material,
Since no distortion of the reproduced output due to the pseudo gap occurs, and no sharp portion of the magnetic core is formed at the interface, it is possible to create a composite magnetic head in which cracks and the like are less likely to occur.

Effects of the Invention In the present invention, after coating a photoresist on a core material, a photomask having a plurality of slits is placed parallel to the photoresist with a gap between the photoresist and the photoresist. The photoresist is developed after being irradiated with light through the photoresist, and the core material is physically etched through the photoresist, so the photoresist is irradiated with light through multiple slits provided in the photomask. Due to the phenomenon of light diffraction, the intensity of the light hitting the photoresist becomes wave-shaped, and the surface of the core material becomes approximately sinusoidal due to physical etching. Therefore, when a metal magnetic film is formed on the surface of the core material, the metal magnetic film and the core material The interface is approximately sinusoidal. After this, grinding and cutting are performed to create two magnetic cores, and by joining these two magnetic cores through a non-magnetic material, there is no pseudo gap, and the metal of the magnetic core is It is possible to create a composite magnetic head in which the portion where the magnetic film is formed does not have a sharp shape, does not generate cracks, and has excellent mechanical strength.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a composite magnetic head manufactured using a manufacturing method according to an embodiment of the present invention, FIG. 2 is a perspective view of a core material, and FIG. 3 is a perspective view of a core material coated with photoresist. 4 is a side view when the photomask is placed, FIG. 5 is a sectional view when a photoresist on a sine wave is formed, and FIG. 6 is a diagram showing the ultraviolet intensity distribution by computer simulation. , Figure 7 is a schematic diagram showing the etching process, Figures 8 to 11 are cross-sectional views of the core material when the incident angle of the ion beam is varied, and Figures 12 to 17 are assembly methods. FIG. 18 is a perspective view of a conventional composite magnetic head, FIG. 19 is a perspective view of another conventional composite magnetic head, and FIG. 20 is a perspective view of another conventional composite magnetic head. 21 to 2.
3 is a sectional view showing the conventional manufacturing method shown in FIG. 20;
FIG. 24 is a perspective view showing another conventional composite magnetic head;
25 to 27 are cross-sectional views showing the conventional manufacturing method shown in FIG. 24, and FIGS. 28 and 29 are cross-sectional views showing the conventional manufacturing method of a mask pattern made of photoresist. 32,':33...32a, 33a...34 35...36...100...37...37a・・・・・・ 38 ・・・・・・ 39 ・・・・・・ 39a・・・・・・ 40 ・・・・・・ 4 1 ・・・・・・ 41a・・・・・・ 4lb ...... 42 ...... Magnetic core winding groove Metal magnetic film Non-magnetic glass Core material groove Photoresist Photomask slit Ion gun rotating core material holder Rotating plate Rotating shaft Metal magnetic film 43 ...・・・ 43a・・・・・・ 44 ・・・・・・ 45 ・・・・・・ 46 ・・・・・・ Core bar winding groove Non-magnetic glass winding Name of agent Patent attorney Shigetaka Awano and others 1 Figure 1 Figure 2 Figure 3 32a 32.33: Magnetic core 32a. 33a: Winding groove 34.35: Metal magnetic film 36: Non-magnetic material 100: Glass Fig. 39: Photomask 39o: Slit Fig. Fig. Fig. A Fig. 41b Two rotational axes Fig. 42: Metal magnetic film Fig. M M Figure 43: Core bar Figure 46jtl line Figures 15, 16: Magnetic core 17.18: Metal magnetic film 19: Non-magnetic material Figure Figure Figure Figure Figure Figure Figure 26: Non-magnetic material Figure Light, light, light, light Figure 31: Mask

Claims (1)

[Claims] After applying a photoresist on a core material made of a magnetic material, a photomask having a plurality of slits is placed with the surface of the photoresist parallel to the photoresist and with a gap between the photoresist and the photoresist. , After irradiating the photoresist with light through the photomask, unnecessary portions are removed by a development process, and after that, the core material is physically etched through the photoresist, and then the processed portion is removed. A composite magnetic head characterized in that a core half is created by forming a metal magnetic film on a metal magnetic film, and the core half and another core half are bonded to each other via a nonmagnetic layer that serves as a magnetic gap. manufacturing method.