JPS63304413A - Thin film magnetic head and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a thin film magnetic head suitable for high-density magnetic recording and reproducing devices such as VTRs and video floppy disks, and a method for manufacturing the same, particularly a multilayer magnetic head with excellent high frequency characteristics. The present invention relates to a thin film magnetic head having a film structure and a manufacturing method thereof.

[Conventional technology]

As an air outlet head for a VTR, a structure has been used in which conventional bulk magnetic cores are butted together to form an operating gap. However, in recent years, due to demands for smaller size and higher performance of VTRs, thin film magnetic heads have been rapidly developed as an alternative to bulk type magnetic heads. Conventionally, thin film misheads have been caused by the formation of a lower magnetic layer 3 on the substrate 10, as shown in the second factor. Nonmagnetic film for gap 4. Insulating material 6. Coil 8. Generally, an upper magnetic layer 5 is laminated, and the core width at the front part is narrowed to improve the magnetic flux density.

However, in order to improve the baton contour accuracy, a head with a structure in which the lower magnetic layer is buried has been proposed in place of the one shown in FIG.

FIG. 3 shows the cross-sectional structure of the head proposed in Japanese Patent Application Laid-Open No. 57-189321, and FIG. 4 shows its tape sliding surface. In this thin film magnetic head, a recess (groove) is formed in a nonmagnetic substrate 1, a lower core 3 is embedded in the recess, and a nonmagnetic layer, a gap material 4. Coil 8. The upper magnetic layer J-5 is laminated. Note that 6a and 6b are insulating materials. According to this structure, the step L of the upper core shown in Fig. 3)
1 can be made smaller than the conventional structure shown in Fig. 2, and the problem of uneven formation of the resist above and below the crotch, which occurs when there is a step when slamming the upper core, can be avoided, making it possible to perform highly accurate slamming contours. There are advantages.

[Problem that the invention seeks to solve]

As shown in FIG. 4, the working gap 4 of the conventional thin film magnetic head is located away from the surface of the substrate 10 by the thickness of the lower core 3, and is parallel to the boundary between the lower core and the substrate. For this reason, there is a drawback that the working gap and the magnetic field at the boundary interfere with each other, causing a so-called contour effect that deteriorates the head characteristics.

Therefore, in order to eliminate this drawback, the inventors of the present invention first changed the shape of the recess (groove) provided in the non-magnetic substrate on the tape sliding surface in the above-mentioned buried structure thin-film magnetic head so that the working magnetic gap So that there are no parallel parts,
We proposed a V-shape or U-shape. According to this proposal, the boundaries of the non-magnetic substrate and the lower core are non-parallel to the working magnetic gap, so that the contour effect is eliminated.

By the way, the thin film magnetic head proposed by the present inventor is as follows:
The recess (groove) consists of a tenth groove for embedding the rear core part of the lower magnetic core and a second groove for embedding the front core part of the lower magnetic core. As a result of further research on the head, it was found that the taper angle of the groove (the degree of inclination measured from the surface of the non-magnetic substrate) was made different between the tenth groove part and the second groove part, and that the roughness of the groove was made different. Friends who find it desirable to be different.

In other words, the finer the surface roughness of the groove, the less rough the embedded magnetic core will be, and the less influence it will have on the magnetic properties (if the roughness becomes severe, the soft magnetic properties will deteriorate). If the magnetic core is rough to some extent, the contact property of the magnetic core with the substrate is improved than if it is fine. This influence on magnetic properties is more significant for the front magnetic core than for the rear magnetic core.

The smaller the taper angle of the housing and groove (the gentler the inclination), the better the smoothness of the magnetic core with respect to the wall surface to be deposited and the better the magnetic properties when depositing the magnetic core by sputtering. In the case of a front magnetic core, if the taper angle is too small, crosstalk with adjacent tracks will occur; in the case of a rear core, there is almost no crosstalk problem), and if the taper angle is too large (i.e. (If the opening angle of the V-groove is small), it is difficult to deposit the magnetic film flatly to a specified thickness by sputtering, and the magnetic material may not even reach the annulus of the V-groove where the magnetic surface is rough. A problem arises in that the magnetic properties are affected. On the other hand, the rear core has a taper angle, but if it becomes large, a problem arises in that the magnetic properties of the lower core deteriorate at the intersection of the first and second grooves.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the contour effect in an embedded type thin film magnetic head by eliminating the drawbacks of the above-mentioned conventional techniques and proposed techniques, and to eliminate the contour effect between the groove in which the front magnetic core is embedded and the groove in which the rear core is embedded. By making the surface roughness and inclination of the groove portions different, problems such as crosstalk, adhesion of the magnetic core to the substrate, and influence on magnetic properties can be solved all at once.

[Means for solving problems]

Ninthly, to achieve the above object, the embedded type thin film magnetic head of the first invention of the present application has a tenth groove portion for embedding the rear core portion of the lower magnetic core and a groove portion for embedding the front core portion of the lower magnetic core. Regarding the second groove part, the tape sliding surface of the second groove part is approximately V-shaped or U-shaped, and the tenth groove part is approximately V-shaped or U-shaped.
The surface roughness of the groove portion is made rougher than the surface roughness of the second groove portion,
Further, the slope of the wall surface of the tenth groove section is configured to be gentler than the slope degree of the wall surface of the second groove section.

In a preferred embodiment, the opening angle of the V-shape to U-shape of the second groove, the radius of curvature of the bottom surface, and the surface roughness are SO° to 90°, 5 μm or more, and 0.5 μm (
0.5s) or less, and on the other hand, the slope of the wall surface of the 10th groove and the surface roughness of each surface are 25° to 25°, respectively.
55° (the degree of inclination is never greater than the slope of the second groove), and 0.6 μm (0.6s) -3μm (3S)
The range of

It is desirable that the groove depth of the second groove section is deeper than the groove depth of the tenth wing section.

In the second invention of the present application, in order to manufacture the T4 film magnetic head configured as described above, an ion etching method is used as a method of forming the tenth groove portion having a rough specific soft surface roughness of the non-magnetic substrate; A mechanical grinding method is used as a method of forming the second groove portion of the nonmagnetic substrate having a relatively fine surface roughness.

[Effect]

With the above configuration, in the embedded type thin film magnetic head of the first invention of the present application, the boundary between the front core part of the lower magnetic core embedded in the substrate recess (groove), particularly the second groove part, and the substrate is The shape is V-shaped or U-shaped and is not parallel to the working magnetic gear lug, resulting in azimuth loss. Therefore, the interference of the magnetic field between the working magnetic gap and the boundary part is reduced to prevent the contour effect from occurring. This improves recording and playback characteristics.

In addition, since the surface roughness of the first groove in which the rear core is embedded is rougher than that of the second groove in which the front core is embedded, the rear core is adhered to the substrate over a relatively large area. The bonding surface of the front core portion ensures enhanced adhesion between the substrate and the lower core, and the front core portion, which tends to affect magnetic properties, is adhered to the substrate wall surface with fine surface roughness. It is smooth with less roughness and does not affect the magnetic properties. Furthermore, by setting the taper angle (angle of inclination measured from the substrate surface) of the wall surface of the 10th groove to a relatively small (gentle) angle, the adhesion of the magnetic layer to be deposited is improved. This prevents deterioration of magnetic properties at the intersection of the two grooves.

On the other hand, crosstalk can be suppressed by setting the taper angle of the wall surface of the second groove portion to a larger value than the taper angle of the wall surface of the tenth groove portion. If the taper angle of the wall surface of the second groove is too large (if the opening angle of the second groove is too small), it will be difficult to uniformly spread the magnetic film deep into the groove by sputtering or the like. Therefore, it is better to limit the lower limit of this opening angle. Good results were obtained with surface roughness and inclination (opening angle) within the above numerical ranges.

By making the groove depth of the second groove deeper than the groove depth of the tenth groove, the magnetic resistance is lowered and the lower magnetic The magnetic resistance of the entire core can be lowered.

In the second invention of the present application, an ion etching method is suitable as a method for forming grooves with relatively rough surface roughness such as the tenth groove, and according to this method, machining is not possible regardless of the substrate material. Concave grooves can be formed in any material such as. In addition, as a method for forming a smooth concave groove with a relatively fine surface roughness like the second groove, a mechanical grinding method using a diamond grindstone or the like is suitable. This is convenient for forming grooves with high precision.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 5. FIG. 1 shows a sliding surface of an embodiment of a thin film magnetic head according to the present invention. FIG. 5 is a sectional view taken along the line A-A' in FIG. 1 of an embodiment of the thin film magnetic head according to the present invention.

The structure of the thin film magnetic head according to the present invention is that a magnetic film 3 formed on a non-magnetic substrate 10 such as glass or ceramic is used as a lower core, and a gap material 4, a signal coil 8, and an insulating material formed on the lower core. A magnetic film 5 is formed via 6a and 6b and used as an upper magnetic core, and a magnetic circuit is formed by the magnetic film 3.5. 7 is a protective film.

The magnetic films 3 and 5 are made of permalloy, sendust, amorphous alloy, or the like. In this example, a Co-Nb-Zr amorphous alloy film formed by a sputtering method was used. The film thickness is approximately 1 to 1 μm.

Gap material 4 is Sin, , ! '-1,0. Non-magnetic insulating materials such as Cr, Zr and other non-magnetic insulating materials can be used. In this example, S io2 was formed to a thickness of 0.3 μm by sputtering. Signal coil 8 is Cu
An insulating material 6a such as Sin is formed around the insulating material 6a.

It is surrounded by 6b.

As shown in FIG. 1, the sliding surface of the thin film magnetic head of the present invention has a structure in which the lower core is embedded in a hole provided in the substrate. Further, by forming this groove into a V-shape or a U-shape with a curved bottom when viewed from the magnetic tape sliding surface, the boundary line between the lower core and the substrate is prevented from being parallel to the working gap 4.

Further, the boundary line of the upper core 5 is similarly shaped to have a curvature so as not to be parallel to the working gap. As a result, in the magnetic head of the present invention, the boundaries between the upper and lower cores on the sliding surface of the chip are not parallel to the working gap, so it is possible to reduce the interference of the magnetic field at the boundary between the working gap and the magnetic core. Contour effects can be eliminated.

The opening angle θ of the V-shaped groove in which the lower core is embedded is determined by the depth D and width W of the groove shown in FIG.

As mentioned above, if the opening angle is too small, it will be difficult to uniformly and flatly deposit a magnetic film with the required thickness by sputtering, etc., and the magnetic layer will become rough, which will affect the soft magnetic properties. must be 50' or more (65° or less in terms of the taper angle described later). On the other hand, if the opening angle is 90
If the opening angle exceeds 90°, the core of the magnetic tape sliding surface expands in the track width direction, increasing crosstalk from adjacent tracks.To avoid this, the opening angle should be 90° or less (
The taper angle must be 45° or more. Furthermore, the radius of curvature R of the bottom surface is similarly determined by the depth of the groove and 1, but what is important is that the bottom surface of the groove has no part parallel to the working magnetic gap.

A V-shaped groove that does not have a radius of curvature R on the bottom surface of the groove can be considered, but if the magnetic material does not spread over the deepest part 1 of the groove, the step coverage of the magnetic film deposited inside the groove will be affected. There are problems with this, and processing is difficult. The R of this groove bottom surface is at least 5 μmR or more. Further, the surface roughness of the bottom surface of the groove is set to within 0.5 μm (0.5 s) so as not to affect the characteristics of the magnetic film.

If it becomes rougher than this, the magnetic properties will deteriorate.

FIG. 6 shows a substrate in which a groove for embedding the lower core has been processed. Non-magnetic substrates such as glass and ceramics
Use ion milling to cut the groove 9 in the rear core part from 20 to 20.
After processing to a depth of 30 μm, a V-shaped groove 2 in the front core portion is machined using a diamond blade whose tip is formed into a predetermined V-shape by machining such as a dicing saw. At this time, from the horizontal surface of the side wall surface of the groove 9 in the rear core part, fl! 1
The taper angle ψ is in a lower range than the similar taper angle of the groove 2 of the front core portion, and is selected in the range from 25° to 55°. The reason for choosing this range is that if ψ exceeds 55°, the magnetic properties of the lower core will deteriorate significantly at the intersection of groove 9 and groove 2, while if ψ becomes 25° or less, the groove 9
This is because precision control of the groove width becomes difficult. Keita, gt
The surface roughness of 9 is from 0.6μm (0.6S) to 3μm
(3s). Surface roughness is 0.6 μm (
If the surface roughness is less than 0.6 s), sufficient adhesion between the substrate 1 and the lower core cannot be obtained, while if the surface roughness is 3 μm (3S) or more, the magnetic properties of the lower core will deteriorate.

Okoro.

Further, as shown in FIG. 6 (not shown in FIG. 5), the depth of the groove 2' is preferably greater than the depth of the groove 9.

Since the width of the groove 2 is limited due to the above-mentioned crosstalk problem, the width of the groove 2 is increased accordingly to prevent an increase in magnetic resistance. On the other hand,
Since the groove width of groove 9 is wider than that of groove 2, even if the groove depth is shallow, the cross-sectional area of the lower rear core can be large, preventing an increase in magnetic resistance, and reducing the ion etching time ( This has the advantage of reducing processing time.

Next, a preliminary manufacturing method for obtaining the thin film magnetic head of the embodiment shown in FIG. 1 will be explained with reference to FIG.

The following steps (a1 to (g) are shown in FIG. 7 (a) to (g))
It corresponds to

(al) The wood 9 for the rear core part of the lower core is attached to the non-magnetic substrate.
is processed to a depth of 25 μm into the shape shown in FIG. 7(a) using the ion milling method.

(b) Next, the front magnetic gap of the lower core is
Use a dicing saw to form the part with an opening angle of 6
00. A V-shaped g2 with a bottom surface radius of 10 μm and a depth of 25 μm is formed by processing. At this time, by using a diamond grindstone with a diamond grain size of 2 to 4 μm, the groove surface roughness can be reduced to 0.
Can be processed to 5S or less.

Hereinafter, the steps (C) to (g) will be explained with reference to the sectional view taken along line BB' in FIG. 7(b).

(cl) Add the magnetic film for the lower core to at least the lower core 3.
The magnetic film is deposited to a thickness that fills the buried trench 2, and the upper surface of the magnetic film is flattened by polishing.

(d) Patterning the Ha magnetic film into a lower core shape by ion milling.

(el After forming the non-magnetic insulating layer 6a, the coil and the re-drying non-magnetic insulating layer, a gap forming surface is created by polishing,
A gap material 4 made of a non-magnetic material is formed.

(f) 2) - in the case of a coil, the second coil, non-magnetic insulation) v! J6b is formed, and a through hole is made in the gap forming part and the rear core connecting part.

(g) A magnetic film is formed by sputtering, and the upper core 5 is formed in the tapered portion of the front through hole drilled in the nonmagnetic insulating layer by contacting the magnetic film by ion milling. This etching is performed at an appropriate beam incidence angle using a photoresist that has been subjected to a predetermined post-baking process as a mask material.

As a result, the upper end surface is curved, so that the contour effect caused by the upper core boundary can be reduced. After that, a protective film 7 is formed.

Through the steps described above, a thin film magnetic head having the sliding surface shape shown in FIG. 1 can be obtained.

Furthermore, although it has been described in the previous embodiment that mechanical grinding is used to form the grooves 2, in this method, as the substrate 1 is ground, the wear of the blade material progresses. An embodiment for this countermeasure will be described using FIG. 8. As shown in the same figure (al), grooves 9a and 9b are formed on the substrate 1 by an ion etching method and a photolithography process.At this time, as shown in the figure, grooves IQa and 10b are used to escape the blade used for mechanical grinding.
are formed at the same time. The cross-sectional shape of the grooves 10a and 10b is as follows:
Make it wider than the blade shape you are using. With this configuration, even when the groove 2 is formed by mechanical grinding, as shown in FIG. 2B, the machining volume can be reduced, making it possible to prevent wear of the blade.

〔Effect of the invention〕

As described in detail above, in the embedded thin film magnetic head of the present invention, the boundary between the front core part of the magnetic core and the substrate is not parallel to the operating magnetic gap on the tape sliding surface. It is possible to prevent the contour effect from occurring.

In addition, by making the surface roughness of the rear core embedding groove rougher than that of the front core embedding groove, it is possible to strengthen the adhesion of the core to the substrate without deteriorating the soft magnetic properties. By making the inclination angle of the front core embedding groove relatively gentle and the inclination angle of the front core embedded groove part relatively steep, excellent effects such as reducing crosstalk between adjacent trunks can be achieved without deteriorating magnetic properties. .

Furthermore, the groove for embedding the rear core part is made using ion etching method.
By forming the front core part embedding groove by mechanical grinding, it is possible to easily create a front groove that requires a fine surface roughness and a high f#f and a rear groove that has a coarse surface roughness.

[Brief explanation of drawings]

FIG. 1 is a tape sliding surface diagram of an embodiment of the thin film magnetic head of the present invention, FIGS. 2 and 3 are sectional views of a conventional thin film magnetic head, and FIG. 4 is a tape sliding surface diagram of a conventional thin film magnetic head. FIG. 5 is a cross-sectional view taken along the line A-A in FIG. (gl is a diagram showing an example of the manufacturing process of the thin film magnetic head of the present invention, FIG. 8(a) (
bl is a diagram showing another example of the manufacturing process of the four-film magnetic head of the present invention. 1...Nonmagnetic substrate, 2...V-shaped groove,
3... Lower magnetic core, 4... Operating magnetic gap, 5... Upper magnetic core, 6.6a, 6
b...--Nonmagnetic insulating material, 7...--Protective film,
8... Coil conductor...9, 9a. 9b... Rear magnetic core embedding groove, 10a, 1
0b...Groove. Figure 1 Figure 2 Poetry j 4゛l Figure 3 C Figure 4 is j Figure 5 Figure 7 (a) B' (C) Figure 7 (d) 6b Cf Figure 7 Figure 8 (b ) 29σ lOo9blOb

Claims (4)

[Claims] (1) In a thin film magnetic head in which a lower magnetic core is buried in a groove formed on a non-magnetic substrate, and a magnetic gap layer, a thin film coil, and an upper magnetic core are sequentially laminated thereon, the groove is located at the lower magnetic core. and a second groove for embedding the front core of the lower magnetic core, and the shape of the tape sliding surface of the second groove is approximately V-shaped to U-shaped. The surface roughness of the first groove is made rougher than the surface roughness of the second groove, and the slope of the wall of the first groove is equal to the slope of the wall of the second groove. A thin-film magnetic head that is characterized by being more gentle than the previous one. (2) the opening angle and radius of curvature of the bottom of the second groove;
The surface roughness is set to 50° to 90°, 5 μm or more, and 0.5 μm (0.5 s) or less, respectively, and the slope and surface roughness of the wall surface of the 10th groove are 25° to 55°, respectively.
2. The thin film magnetic head according to claim 1, wherein the thin film magnetic head is configured to have a width of 0.6 μm (0.6 s) to 3 μm (3 s). (3) The groove depth of the second groove part is made deeper than the groove depth of the first groove part.
The thin film magnetic head described in Section 1. (4) A lower magnetic core is buried in a groove formed on a non-magnetic substrate, and a magnetic gap layer, a thin film coil, and an upper magnetic core are laminated in this order on the lower magnetic core, and the groove is buried in the rear core part of the lower magnetic core. and a second groove for embedding the front core part of the lower magnetic core, and the tape sliding surface of the second groove has a substantially V-shaped or U-shaped shape. , a thin film in which the surface roughness of the first groove is rougher than the surface roughness of the second groove, and the slope of the wall of the first groove is gentler than the slope of the second wall. 1. A method of manufacturing a thin film magnetic head, wherein the first groove is formed by an ion etching method, and the second groove is formed by a mechanical grinding method.