JPH0758532B2 - Magnetic head - Google Patents

Description

The present invention relates to a magnetic head for recording / reproducing such as a VTR or a video floppy disk, and more particularly to a magnetic head having no characteristic deterioration even in a high frequency region.

[Conventional technology]

Along with the improvement in recording density, metal tapes with large coercive force have been developed for VTRs instead of the conventional oxide magnetic tapes. For this reason, the head material has also been changed from a ferrite-based material to a metal-based magnetic material having a higher saturation magnetic flux density.

On the other hand, the recording wavelength has been shortened with the times.
Therefore, the head material is also required to extend the frequency characteristic of the magnetic permeability μ to a higher range. However,
When a metallic magnetic material is used as the head material, eddy current loss occurs due to its low specific resistance. Therefore, it has been considered to thin a film made of a metallic magnetic material and stack a large number of the films to form a magnetic layer having a predetermined thickness. FIG. 6 shows the frequency characteristics of magnetic permeability in a magnetic head having such a magnetic layer having a multilayer structure. As is clear from the figure, a metallic magnetic material having a specific resistance ρ of 1.5 × 10 ⁻⁶ Ω · m. In order to set μ to 2000 or more up to 10 MHz, it is necessary to make the thickness of the metal magnetic material film, that is, the metal magnetic thin film 4.0 μm or less per layer to form multiple layers.

As a magnetic head for VTR using a metal magnetic thin film, for example, one developed by Mr.
A metal magnetic thin film is used as the sputtering film and a non-magnetic insulating silicon oxide film is used as an insulating interlayer material, and these are alternately laminated in multiple layers,
There is known a magnetic head in which a gear is formed by a glass bonding method (Japanese Patent Laid-Open No. 49-127195).

FIG. 7 is a plan view of such a magnetic head as seen from the sliding surface side of a magnetic recording medium, in which 1 is a substrate, 2a and 2b are metal magnetic thin films, 3 is an interlayer material, and 4 is a gear tape made by a glass bonding method. , 5 and 6 are magnetic layers.

In the figure, the magnetic layer 5 has a multi-layer structure in which the metal magnetic thin films 2a and the non-magnetic insulating interlayer material 3 are alternately laminated, and the magnetic layer 6 also includes the metal magnetic thin film 2b and the interlayer material 3 alternately. Has a multi-layered structure. These magnetic layers 5 and 6 are provided between the substrates 1. This magnetic head is a magnetic thin film
The core half on the left side with respect to the gap 4 containing 2a and the core half on the right side with respect to the gap 4 containing the magnetic thin film 2b are joined together by a glass melting method, and the joint part is used as a gap 10. . In this joining process, it is very difficult to join these two core halves with high accuracy, and an error is likely to occur in the track width of the gear, so this magnetic head has problems in mass productivity and retention. There is.

On the other hand, a magnetic head aiming at improving the mass productivity with high accuracy has also been developed by adopting the latest wafer process technology in addition to the formation of the gear tape without using the glass tape forming method by the glass bonding method. (Jitsuko Sho 43-13255).

FIG. 8 is a plane viewed from the magnetic recording medium sliding surface (hereinafter simply referred to as “sliding surface”) side of the magnetic head manufactured by the film deposition method using the wafer processing technique without using the glass bonding method. In the figure, 1 is a substrate, 2a and 2b are metallic magnetic thin films, 4 is a non-magnetic gap material, and 5 is a protective film. Further, FIG. 9 is a manufacturing process diagram of the magnetic head shown in FIG. The manufacturing process is performed in the following order.

(1) First, the substrate 1 (FIG. 9A) is formed, and the first metal magnetic thin film 2a is formed on the substrate 1 by sputtering or the like (FIG. 9B).

(2) Next, a part of the metal magnetic thin film 2a is removed until the substrate 1 appears, and a non-magnetic gap material 4 is formed on the surfaces of the metal magnetic thin film 2a and the substrate 1 by sputtering or the like (FIG. 9). (C)).

(3) Then, the second metallic magnetic thin film 2b is formed on the entire surface of the gear material 4 by sputtering or the like (FIG. 9 (d)).

(4) Then, the metal magnetic thin film is formed by lapping or the like.
To the extent that the gear material 4 on 2a is removed, a metallic magnetic thin film
A part of 2b is removed (Fig. 9 (e)). As a result, the metal magnetic thin film is formed on the substrate 1 with the gear 4 interposed therebetween.

(5) Further, a protective film 7 is formed thereon by vapor deposition or the like (FIG. 9 (f)).

Through the above steps, the magnetic head can be formed by the film deposition method. FIG. 8 shows a magnetic head of this type in which the magnetic layer is formed of a single-layer metal magnetic thin film. When a magnetic layer is formed by laminating multiple layers of metal magnetic thin films with this type of magnetic head. 9 (b) and 9 (d), instead of the single-layer metal magnetic thin films 2a and 2b, metal magnetic thin films and interlayer materials are alternately laminated in multiple layers. In the step d), a structure as shown in FIG. 10 is obtained. As a result, as shown in FIG. 11, the magnetic head completed through the same steps as in FIGS. 9 (e) and (f) has one magnetic layer with respect to the gear 4 as viewed from the sliding surface side. The metal magnetic thin film 2a and the insulating interlayer 3 have a multilayer structure, and the other magnetic layer also has a multilayer structure of the metal magnetic thin film 2b and the insulating interlayer 3.

[Problems to be solved by the invention]

By the way, in the non-bonding type (type not using the glass bonding method) and the above-mentioned multilayer metal magnetic film magnetic head using the film deposition technique, as shown in FIG. Is parallel to the surface formed by a part 3'of the above (since the angle formed by both surfaces is θ, θ = 0 °). For this reason, the portion 3'of the insulating interlayer 3 which is parallel to the surface formed by the gear tape 4 acts as a pseudo gear tape, and recording is performed with this gear tape 4 as well. Since the recording strength of the pseudo gear tape is sufficiently smaller than the recording strength of the gear tape 4, there is no problem in reproducing what was recorded with the pseudo gear tape with the pseudo gear tape. Playback, or playback of what was recorded with the pseudo gearup by the gearup 4, the level of the playback signal due to these is quite high, and it is mixed with the original signal recorded by the gearup 4 and played back by the gearup 4. That S /
N will be deteriorated.

Japanese Patent Application Laid-Open No. 57-13
A magnetic head disclosed in Japanese Patent No. 8021 has been proposed.
This magnetic head is a non-bonding type multi-layer magnetic metal film magnetic head, and as shown in FIG.
Is cut so that a V-shaped groove reaching the substrate is formed, and a layer 8 of a magnetic metal material is deposited and embedded in the cut groove. According to this, the nonmagnetic insulating layer 9 is provided between the layer 8 of the magnetic metal material and the magnetic layer 6 made of the metal magnetic thin film 2b.
Is a pseudo gear trap, but the surface of this pseudo gear trap is not parallel to the surface of the gear trap 4 (160 °), and the influence of this pseudo gear trap does not appear due to the azimuth effect.

However, when manufacturing such a magnetic head, there is a problem in that mass productivity is poor because an additional groove forming and burying step for providing the magnetic metal layer 6 is added.

The object of the present invention is to eliminate such problems, eliminate the deterioration of S / N based on the pseudo gear tape, and have excellent high frequency characteristics,
Moreover, it is to provide a magnetic head excellent in mass productivity.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a non-bonding type multi-layered metal magnetic film magnetic head using a film deposition method, in which a metal magnetic film of a magnetic layer is formed with respect to a gear surface. The surfaces of the insulating interlayer material interposed therebetween are made non-parallel.

[Action]

When viewed from the sliding surface, the angle between the surface of the insulating interstitial material and the gear surface is θ (radian) (both are parallel when θ = 0), the effect may be considered as azimuth loss,
According to the following equation (1), the reproduction output of the signal recorded by the pseudo gear tape by the gear tape decreases as θ increases.

Here, W is the track width, λ is the recording wavelength, and La is the relative reproduction output when the reproduction output at θ = 0 is 0 dB. θ
If the angle is 5 ° or more, preferably about 20 °, the influence of the pseudo gear trap can be ignored.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of an embodiment of a magnetic head according to the present invention viewed from the sliding surface side, and the same reference numerals are given to the portions corresponding to the above-mentioned drawings.

In the figure, a first magnetic layer 5 and a second magnetic layer 6 are provided on a substrate 1 with a non-magnetic gap 4 interposed therebetween.
Each of the magnetic layers 5 and 6 has a multi-layer structure in which metal magnetic films 2a and 2b such as sendust and amorphous and a non-magnetic interlayer material 3 such as SiO ₂ are alternately laminated to form a multilayer structure.
A protective film 7 is formed on the top. As will be apparent from the description of the manufacturing method described later, the surface of the interlayer material 3 of the magnetic layer 5 is parallel to the surface of the substrate 1 and is not parallel to the surface of the gear 4, but the magnetic layer 6 is further The surface of the interlayer material 3, including the vicinity of the gear 4, is not parallel to the surface of the gear 4 (θ ≠ 0). Therefore, the interlayer material 3 does not act as a pseudo gear trap.

Next, the manufacturing method will be described with reference to FIG.

(1) First, a non-magnetic substrate 1 is formed of glass or the like (FIG. 2 (a)), and a magnetic thin film 2a made of sendust, amorphous or the like and a non-magnetic insulating interlayer material made of SiO ₂ or the like. 3 and 3 are alternately laminated up to a predetermined film thickness by sputtering, vapor deposition or the like. (FIG. 2 (b)) (2) Next, a part of this laminated body is removed up to the surface of the substrate 1 by patterning, machining or the like to form a magnetic layer 5 having an inclined surface 10 to be a gear surface. . (Fig. 2 (c)) (3) Si to be the gap 4 on the magnetic layer 5 and the substrate 1
An O ₂ film is formed, and one layer of the magnetic thin film 2b is laminated on the entire SiO ₂ film. (FIG. 2 (d)) (4) Next, a thin resist is applied to the step portion 11 of the magnetic thin film 2b, the resist is thinned, and then ion milling is applied to the entire surface so that the resist is removed. Loosen the angle of. (FIG. 2 (e)) (5) Then, the interlayer material 3 is formed on the first magnetic thin film 2b.
And magnetic thin films 2b are alternately laminated in multiple layers. (FIG. 2 (f)) (6) The entire magnetic layer 5, 6 is lapped so that the layer of the magnetic thin film 2b on the magnetic layer 5 and the interlayer material 3 is removed.
To a predetermined track width. (FIG. 2 (g)) (7) Finally, a non-magnetic film such as forsterite is formed on the magnetic layers 5 and 6 by vapor deposition or the like to form the protective film 5. (FIG. 2 (h)) With the above, the magnetic head 6 shown in FIG. 1 can be manufactured.
In the above manufacturing method, in the steps (3) and (4) (FIGS. 2D and 2E), the stepped portion of the first magnetic film 2b is formed.
A resist and a milling process are used to make 11 not parallel to the four faces of the gear, but the present invention is not limited to this. For example, during sputtering for forming a magnetic film, the step portion is loosened by bias sputtering for applying an RF bias. How to do
It may be formed by a method of biasing CVD instead of sputtering. Further, in the above description, since the angle of the stepped portion 11 is made gentle only in the first magnetic film 2b, the interlayer materials 3 above it are parallel to each other, but the invention is not limited to this. As shown in the figure, the magnetic thin films 2b may be subjected to the above steps (3) and (4) to gradually increase the angle θ formed between each interlayer material 3 and the gear 4 (θ ₂ >
θ ₁ ).

Also, as shown in FIGS. 4 and 5, the first magnetic thin film 2b is formed.
After forming the film, the step surface or the entire surface may be roughened by ion milling or the like, and then the magnetic thin films 2b and the interlayer material 3 may be alternately laminated in multiple layers. Also in this case,
The surface formed by the interlayer material 3 and the surface formed by the gear 4 are not parallel to each other. That is, when the magnetic layer 6 after forming the gap is formed into multiple layers, the forming method is not limited as long as the interlayer material can be made non-parallel to the gap surface as viewed from the sliding surface side.

Now, next is the area on the sliding surface where the interlayer material and the gear surface should be non-parallel when viewed from the sliding surface side, but this is 100 μ at most from the position of the gear surface.
Good within m. Because it is 100μm from the gear position.
This is because at the positions separated from each other, a sufficient tape touch can no longer be obtained, and the influence of the pseudo gear tape can be ignored due to the spacing loss.

〔The invention's effect〕

As described above, according to the present invention, in the multilayer metal magnetic thin film magnetic head by the non-bonding and film deposition method, the surface of the interlayer material is made non-parallel to the surface of the gear tape at least near the surface of the sliding surface. Therefore, while improving the characteristics up to a sufficiently high range, even if the interlayer material acts as a pseudo gear trap, it is possible to prevent deterioration of the reproduction output S / N due to this, and moreover, to eliminate the influence of the pseudo gear trap, Since it is not necessary to add complicated steps, excellent effects such as mass productivity and improved yield can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a magnetic head according to the present invention, FIG. 2 is a process drawing showing its manufacturing method, and FIGS.
FIG. 6 is a plan view showing another embodiment of the magnetic head according to the present invention, FIG. 6 is a frequency characteristic diagram of magnetic permeability in the magnetic head, and FIGS. 7 and 8 are plan views showing conventional examples of the magnetic head. FIG. 9 is a process drawing showing the method of manufacturing the magnetic head shown in FIG. 8, FIG. 10 is a partial process drawing when the magnetic layer has a multilayer structure in this manufacturing method, and FIG. 11 is FIG. FIG. 12 is a plan view showing a magnetic head according to the manufacturing method shown in FIG. 12, and FIG. 12 is a plan view showing another conventional example of the magnetic head. 1 ... Substrate, 2a, 2b ... Metal magnetic thin film, 3, 3 '... Interlayer material, 4 ... Gear tape, 5, 6 ... Magnetic layer, 7 ... Protective film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Akai 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Home Appliance Research Laboratory, Hitachi, Ltd. (72) Inventor Tomoko Yoneyama 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa (56) References JP 61-230611 (JP, A) JP 60-234209 (JP, A)

Claims (1)

[Claims] 1. A single substrate formed as one body is provided with first and second magnetic layers with a gap between them, the first magnetic layer being provided on the surface of the substrate. The metal magnetic thin film and the insulating interlayer material are alternately laminated in multiple layers, and the second magnetic layer has the metal magnetic thin film and the insulating interlayer material alternately laminated on the surface of the substrate and the gap. In the laminated magnetic head, at least the film thickness of the metal magnetic thin film in contact with the gap in the second magnetic layer is non-uniform, 2. A magnetic head characterized in that the surface of the insulating layer material of the second magnetic layer is entirely non-parallel to the surface of the gap.