JPH0330105A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To lower electric resistance as far as possible and to allow the multiple winding of coil conductors by adequately distributing the sectional areas of the coil conductors of respective layers of two layers of the coil conductor is larger than the sectional area of the 1st layer coil conductor. CONSTITUTION:A lower magnetic film 14 and a magnetic gap film 15 are successively formed on an insulating film 12. The 1st coil conductor 17, an insulating film 19, the 2nd coil conductor 18, and an upper magnetic film 16 are then formed. The surface on which the 2nd coil conductor 18 is formed is nearly flush with the surface of the insulating film 12 and the accuracy in the case of producing photoresist patterns is enhanced. The sectional area of the 2nd layer coil conductor 18 is made larger than the sectional area of the 1st layer coil conductor 17 by making use of the feasibility of producing the 2nd layer coil conductor 18 with good accuracy. The coil resistance is lowered in this way and the electric resistance over the entire part of the coil conductor is reduced, by which the multiple winding of the coil conductors is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head, and particularly to a thin film magnetic head suitable for achieving high magnetic recording density.

[Conventional technology]

Thin-film magnetic heads have a magnetic core with a small volume and low inductance, the high-frequency permeability of the magnetic film is higher than that of bulk ferrite, and narrower tracks are possible by manufacturing using ring graphite technology. Because of these many advantages, it is becoming increasingly important in the field of magnetic disk drives, magnetic tape drives, and consumer magnetic recording in order to improve areal recording density.

Areal recording density is the product of bit density and track density. If the structure of the thin-film magnetic head is the same, the reproduction output of the thin-film magnetic head will decrease as the bit density or track density increases, and signals may be read incorrectly. In order to solve these problems associated with the increase in recording density, a method has been adopted in which the number of turns of the four coils is increased to increase the reproduction output to prevent erroneous reading of the signal.

For example, U.S. Patent No. 421.9854 discloses a thin film magnetic head with an eight-turn coil conductor in 1980; Page 4157-(
1987), (J, Appl. Phys., and
4157 (1987). ) reported a thin-film magnetic head with a two-layer, 17-turn coil conductor. An effective method for increasing the number of turns of the coil conductor of a thin-film magnetic head is to make the coil conductor have a two-layer structure, as described in Journal of Applied Physics, Vol. 61, p. 4157 (19177). .

However, when the coil conductor has a two-layer structure, the distance between the upper and lower magnetic films that sandwich the two-layer coil conductor and the insulating film becomes large. , since the machining process requires machining at the bottom of the high step part, there is a problem that the machining accuracy deteriorates. In order to improve this processing accuracy, for example, as shown in Japanese Patent Laid-Open No. 62-243108, a recess is provided on the substrate, a lower magnetic film is formed in the recess, and then an insulating film and a coil conductor are formed. , after sequentially forming,
By widening the direction in which the upper magnetic film is formed and processed, the upper magnetic film can be processed on a lower level difference than in the conventional example, and the accuracy of the track width can be improved.

[Problem to be solved by the invention]

It is important that the coil conductor has low electrical resistance within a predetermined magnetic path length, has little manufacturing variation, and has multiple windings. It is easy to increase the number of windings by increasing the magnetic path length, but this increases the leakage of magnetic flux between the upper and lower magnetic films, lowering the efficiency of the thin-film magnetic head and reducing the recording magnetic field. Undesirable. Another possibility is to reduce the width of the coil conductor and increase the number of turns, but in this case, the electrical resistance increases, which increases the noise of the thin-film magnetic head, which is not preferable. However, the prior art does not take into consideration lowering the resistance by increasing the number of turns and layers of the coil conductor, and there is a problem in improving the performance of the thin film magnetic head.

SUMMARY OF THE INVENTION An object of the present invention is to provide a structure of a thin film magnetic head that can reduce electrical resistance as much as possible and increase the number of turns of a coil conductor.

[Means to solve the problem]

In order to achieve the above objective, the cross-sectional area of the coil conductor in each layer of the four two-layer coils constituting the thin-film magnetic head is appropriately distributed, and the cross-sectional area of the second layer coil conductor is the cross-sectional area of the first layer coil. By making the area larger than the area, the electrical resistance is lowered.

Further, in order to increase the cross-sectional area of the second layer coil conductor, the height of the second layer coil conductor is made larger than the height of the first layer coil conductor.

Further, in order to increase the cross-sectional area of the second layer coil conductor, the width of the second layer coil conductor is made larger than the width of the first layer coil conductor.

In addition, in order to achieve the above purpose, by making the pitch of the second layer coil conductor smaller than that of the first layer coil conductor,
It has lower electrical resistance.

Furthermore, in order to achieve the above object, the taper angle of the second layer coil conductor is made larger than that of the first layer coil conductor.

[Effect]

As a method for manufacturing the coil conductor of a thin film magnetic head, a method of forming the coil conductor using a photoresist pattern as a mask and a tightening method has been adopted. A model diagram of an example of a method for manufacturing a coil conductor is shown in FIG. First, as shown in FIG. 2(a), a base film 10 for four-piece plating is formed. Next, the photoresist film 9
(b) except for the coil fabrication part. Next, the plating film 4 is shaped (C), and the photoresist film 9 used as a mask is removed (D). Finally, unnecessary portions of the plating base film are removed using an etching method such as sputter etching or ion milling to produce a coil conductor (e). As can be seen from this figure, an important factor that determines the cross-sectional shape of the coil conductor is the cross-sectional shape of the photoresist film 9 used as a mask.

In order to control the cross-sectional shape of the photoresist film, it is necessary to control the cross-sectional shape of the photoresist pattern during the photoresist pattern fabrication process by adjusting the uniformity of the photoresist film thickness, defocusing during pattern exposure, and fluctuations in development conditions. It is a factor that determines or changes the shape. Therefore, it is clear that the above-mentioned shape variation factors during the formation of a photoresist pattern largely depend on the shape of the substrate surface on which the photoresist pattern is formed.

In the *yIA magnetic head of the present invention, four parts are provided on a substrate, a part of the lower magnetic film is formed on these four parts, an insulating film and a coil conductor are sequentially formed, and then an upper magnetic film is formed. In this case, since the part where the first layer coil conductor is to be formed is the bottom of the four parts dug from the substrate surface, it is necessary to create a resist pattern in the part where the step is created. Therefore, pattern accuracy is lower than in the case of forming a photoresist pattern on a flat substrate. On the other hand, in the second layer coil conductor, the recess dug into the substrate surface is filled with the first layer coil conductor and the insulating film, so the second layer coil conductor is placed almost on the same plane as the substrate surface. Since the photoresist pattern for forming the conductor is produced, the photoresist pattern can be produced with higher precision than when producing the photoresist pattern for the first layer coil conductor.

Therefore, it has been found that when manufacturing a two-layer coil conductor for a thin film magnetic head, the second layer coil conductor can be manufactured with higher dimensional accuracy than the first layer coil conductor.

As mentioned above, in order to improve the performance of the thin film magnetic head, it is necessary to increase the number of turns of the coil conductor and to reduce the electrical resistance of the coil conductor as much as possible. Therefore, by taking advantage of the fact that the photoresist pattern shape of the second layer coil conductor can be fabricated with higher precision than that of the first layer coil conductor, the cross-sectional area of the second layer coil conductor is smaller than that of the first layer coil conductor. or by making the pitch between the conductors of the second layer coil conductor smaller than the pitch between the conductors of the first layer coil conductor, the electrical resistance of the second layer coil conductor can be increased. 1 of the entire coil conductor! Thin 1 by reducing air resistance! fi6J1Ki... This is intended to improve the performance of the engine.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. This figure shows a Wrm diagram of the thin film magnetic head of the present invention. An insulating film 12 is formed on the substrate ↓1. A ceramic material can be used for the substrate l1, and an alumina film formed by a sputtering method can be used for the insulating film 12. A hole is formed on this insulator 1 to bury the lower magnetic film 14 and the like. On the insulating film 12, Ni
A lower magnetic film 14, which is an Fe film or a Co-based alloy film, and a magnetic gap film 15, which is made of alumina or the like, are sequentially formed. Next, for example, an insulating film 19 using a thermoset photoresist film, a first coil conductor 17 using a copper plating film, an insulating film 19, a second coil conductor 18, and an insulating film 19 are formed. Then, NiF
The upper magnetic film 16, which is an e-film or a Co-based alloy film,
One end faces one end of the lower magnetic film 14 via the magnetic gap film 15, and the other end directly contacts and continues with the lower magnetic film 14. An insulating film 13 such as an alumina film formed by sputtering is formed thereon.

As shown in this example, the surface on which the first coil conductor is fabricated is at a deep position with respect to the surface of the insulating film l2, which is the substrate surface. On the other hand, the surface on which the second coil conductor is fabricated is almost the same plane as the surface of the insulating film l2, which is the surface of the cutting board, and the accuracy when fabricating the photoresist pattern 1 used as a plating mask is lower than that of the first coil conductor. Good for comparison during production.

In this example, the cross-sectional area of the second coil conductor is larger than that of the first coil conductor, and the height of the plating film is increased. The magnetic path length is 1001tm, the coil pitch is 5.754m, the bottom dimension of the coil is 2.75μm,
When the taper angle of the lower section of the coil was 96° and the height of the first coil conductor and the second coil conductor was 3 μm, the resistance value of all the coil conductors was 19.7Ω. On the other hand, as shown in this example, the height of the second coil conductor is increased to 4 μm to increase the absolute area.
．． It was found that the resistance could be lowered by 6Ω. <Embodiment 2> FIG. 3 shows, as another embodiment of the present invention, an embodiment in which the cross-sectional area is increased by increasing the width of the second layer coil conductor. In this example, the magnetic path length is 100 μm, the coil pitch is 5.75 μm, the coil thickness is 3 μm, the taper angle at the bottom of the coil cross section is 96″, and the width of the lower end of the coil of the first coil conductor is 2.75 μm. , the lower end width of the second coil conductor is 0.5 μnl wider than the lower end width of the first coil conductor.
The width is 3.25 μm. The resistance value of the entire coil in this case is. It was 18.8Ω.

Therefore, it was found that the coil resistance could be reduced by 0.9Ω by widening the lower end width of the second coil by 0.5 μm.

Embodiment 3 FIG. 4 shows another embodiment of the present invention in which the pitch of the second layer coil conductor is reduced to increase the cross-sectional area and reduce the coil resistance. In this example, the magnetic path length is 100 μm, the coil thickness is 3 μrn, the taper angle of the lower part of the coil cross section is 96°, and the coil lower end angle is 2.7 μm.
5μm, and the coil pinch of the first coil is 5.75μm.
m, the coil pitch of the second coil was reduced by 0.25 μm compared to the first coil to 5.50 μm.

The resistance value of the entire coil in this case was 19.0Ω. Therefore, by making the pitch of the second coil 0.25 μm smaller than the pitch of the first coil, the coil resistance can be reduced to 0.25 μm.
It was found that it was possible to reduce the resistance by 7Ω.

Embodiment 4> FIG. 5 shows another embodiment of the present invention in which the height of the second coil conductor is increased, the width is widened, and the pitch is decreased to increase the cross-sectional area of the coil. An example will be shown in which the resistance is reduced. In this example, the magnetic path length is 100μ
m, the taper angle at the bottom of the coil cross section is 96°, the height of the first coil is 3 μm, and the width of the lower end of the coil is 2.7
The 5 μm coil pitch was 5.75 μm, the height of the second coil was 4 μm, the width of the lower end of the coil was 3.25 μm, and the coil pitch was 4 μm. The resistance value of the entire coil in this case is. It was 16.6Ω.

Therefore, it has been found that the coil resistance can be reduced by 3.10 by making the second coil higher in height, wider in width at the lower end of the coil, and smaller in pitch than the first coil.

Embodiment 5> FIG. 6 shows another embodiment of the present invention in which the cross-sectional area is increased and the coil resistance is reduced by increasing the taper angle of the second coil conductor. In this example, the magnetic path length is 100 μm, the height of the coil is 3 μm, the lower end width of the coil is 2.75 μm, the taper angle of the first coil conductor is 96', and the taper angle of the second coil conductor is 3 μm. 1
00°. The resistance value of the entire coil in this case was 19.3Ω. Therefore, it was found that by making the taper angle of the second coil larger than that of the first coil, the coil resistance could be reduced by 0.4Ω.

<Embodiment 6> FIG. 7 shows, as another embodiment of the present invention, an embodiment in which the pitch of the second coil conductor is reduced and the number of turns of the coil is increased. In this example, the magnetic path length is 100 μm, the height of the first coil is 3 μm, and the lower end width is 2.75 μm.
The second coil has a taper angle of 96°, 14 turns, and a pitch of 5.75 μm, while the height of the second coil is 3.2 μm, the width of the lower end is 2.75 μm, the taper angle is 96°, 14 turns, and the pitch is 5.34 μm. In this case, the resistance value of the entire coil is 1
9.6Ω, the height of the first and second coils is 3μm, the lower end width is 2.75μm, the taper angle is 96°, and the pitch is 5.75μm.
The resistance value is almost the same as the resistance value of the entire coil (19.7Ω) when the number of turns is 13 turns each (26 turns in total), and the total number of turns can be increased by one turn, increasing the output by about 4%. It was found that the S/N ratio can be improved.

〔Effect of the invention〕

According to the present invention, a coil with low electrical resistance can be manufactured for a predetermined magnetic path length and a predetermined number of coil conductor turns.
This makes it possible to achieve low noise in thin-film magnetic heads and prevent erroneous reproduction of signals even at high recording densities.

Furthermore, according to the present invention, multiple windings can be realized for a given magnetic path length and a given electrical resistance of the coil conductor, so even at high recording densities, a large reproduction output can be obtained and signals can be reproduced by mistake. You can prevent it from happening.

[Brief explanation of drawings]

1, 3, 4, 5, 6, and 7 are cross-sectional views of thin-film magnetic heads according to embodiments of the present invention, and FIG.
It is a sectional view showing a manufacturing process. 2... Magnetic film, 4... Plating film, 6... Gap film, 7... Insulating film, 9... Photoresist film, 10...
... Plating base film, 11... Substrate, 12... Insulating film, 13... Insulating film, 14... Lower magnetic film, 15...
Residual gap film, ↓6... Upper magnetic film, 17... First coil conductor, l8... Fig. 2 Fig. 1 3 Fig. 5 Fig. 4 Fig. 6 Fig.

Claims (1)

[Scope of Claims] 1. A lower magnetic film, and an upper part laminated on the lower magnetic ridge, one end of which is connected to one end of the lower magnetic film, and the other end of which faces the other end of the lower magnetic film through a predetermined gap. A coil conductor consisting of a magnetic film and a coil having a two-layer structure arranged so as to penetrate between the lower magnetic film and the upper magnetic film is provided, and a bottom surface of the first coil conductor facing the lower magnetic film is provided. However, in a thin film magnetic head in which the lower magnetic film is formed at a position lower than the bottom surface of the lower magnetic film in a portion facing the upper magnetic film through a predetermined gap, the per turn of the second coil conductor is A thin film magnetic head having a resistance value smaller than a resistance value per turn of the first coil conductor. 2. The thin film magnetic head according to claim 1, wherein the cross-sectional area of the second coil conductor is larger than the cross-sectional area of the first coil conductor. 3. In claim 2, the second coil conductor has a higher coil height, a wider coil width, or a larger coil taper angle than the first coil conductor, or a combination thereof, so that the cross-sectional area A thin film magnetic head characterized by a large . 4. The thin film magnetic head according to claim 1, wherein the pitch of the second coil conductor is smaller than that of the first coil conductor. 5. In claim 1, the pitch of the second coil conductor is smaller than that of the first coil conductor, and the cross-sectional area of the second coil conductor is larger than the cross-sectional area of the first coil conductor. Thin film magnetic head. 6. In claim 5, the second coil conductor has a higher coil height, a wider coil width, or a larger taper angle than the first coil conductor, or a combination of these to reduce the cross-sectional area. A thin film magnetic head characterized by its large size.