JPH097117A - Thin film magnetic head and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] A good hard bake film can be formed by sufficiently heating the resist to be an insulating layer, and good recording and reproducing characteristics can be obtained without deterioration of the soft magnetic characteristics of the magnetic layer. To do so. A gap film 16 separates a lower magnetic layer 14 and an upper magnetic layer 24 provided on a ceramic substrate 10 from each other, and a conductor coil layer 18 is provided between them to form insulating layers 20 and 22 above and below the conductor coil layer. It is an insulated structure.
The lower magnetic layer is a sendust film formed by a vapor deposition method or a sputtering method and annealed at 450 to 500 ° C., and the upper magnetic layer is a permalloy film formed by a plating method and annealed at 300 to 320 ° C. Is.
The insulating layers located above and below the conductor coil layer are resist hard bake films, the processing temperature of which is 340 to 370 ° C., and the annealing temperature of the permalloy film is 40 to 70 ° C.
Set higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head and a method of manufacturing the same. More specifically, the lower magnetic layer comprises a sendust film and the upper magnetic layer comprises a permalloy film. The present invention relates to a thin film magnetic head that suppresses thermal contraction and stabilizes recording / reproducing characteristics.

[0002]

2. Description of the Related Art Generally, in a thin film magnetic head for a hard disk, a lower magnetic layer and an upper magnetic layer provided on a ceramic substrate are separated by a gap film, and a conductor coil layer for magnetic field generation and induction current pickup is formed therebetween. It is configured to do. The conductor coil layer has a structure in which the upper and lower sides are electrically insulated by an insulating layer, and one or a plurality of such conductor coil layers are provided. Therefore, when arranging over a plurality of layers, the insulating layers and the conductor coil layers are alternately stacked. As the material used, the lower magnetic layer and the upper magnetic layer are permalloy films (NiFe films) formed by electroplating or sputtering, and the insulating film is a resist hard bake film cured by heat treatment.

The permalloy film to be the lower magnetic layer and the upper magnetic layer is subjected to annealing treatment (heat treatment) at an appropriate temperature after the film formation to improve the required soft magnetic characteristics.
The annealing temperature at this time is the coercive force Hch (Oe) and the annealing temperature (° C.) for the permalloy film shown in FIG.
Therefore, it is optimal to set the temperature to 300 to 320 ° C. If it exceeds 330 ° C., the soft magnetic properties will be rapidly deteriorated.

On the other hand, if the resist hard bake film constituting the insulating layer is not cured by a necessary and sufficient heat treatment, the heat shrinkage due to the curing will be insufficient, and the resist hard bake film will be further shrunk by the subsequent heat treatment. Here, the heating temperature necessary and sufficient to cure the resist is 340 to 3 which is 40 to 70 ° C. higher than the optimum heat treatment temperature of Permalloy of 300 to 320 ° C.
It is about 70 ° C. However, this heating temperature is a temperature that deteriorates the soft magnetic characteristics of the already formed permalloy film of the lower magnetic layer (see FIG. 4).

Therefore, in the prior art, the annealing temperature of the lower magnetic layer (permalloy film), the hard baking temperature of the insulating layer (resist), and the upper magnetic layer (permalloy film).
The annealing temperature was set to 300 to 320 ° C. so as to suit the improvement of the soft magnetic properties of the permalloy film.

[0006]

In order to sufficiently cure the resist hard bake film forming the insulating layer, it is necessary to perform heat treatment at 340 to 370 ° C. as described above. However, in order to avoid a thermal adverse effect on the permalloy film forming the lower magnetic layer, it is unavoidable that 300
It was heated to ~ 320 ° C and hard-baked. This temperature is rather low for hard baking the resist and the heat shrinkage is insufficient. For this reason, when the permalloy film forming the upper magnetic layer is annealed to improve the soft magnetic characteristics, the resist further shrinks. As a result, the permalloy film forming the magnetic layer is stressed, and the effect of improving the soft magnetic characteristics originally possessed by the permalloy film becomes insufficient, so that good recording / reproducing characteristics cannot be obtained.

An object of the present invention is to perform a necessary and sufficient heat treatment on a resist to be an insulating layer to form a good hard bake film and to prevent the lower magnetic layer from being thermally adversely affected. (EN) Provided is a thin film magnetic head capable of suppressing the heat shrinkage of the magnetic recording layer, preventing the soft magnetic characteristics of the magnetic layer from deteriorating, and obtaining good recording and reproducing characteristics, and a method for manufacturing the same.

[0008]

According to the present invention, a lower magnetic layer and an upper magnetic layer provided on a ceramic substrate are separated by a gap film, and a conductor coil layer is provided between them.
The induction type thin film magnetic head has a structure in which the upper and lower sides of the conductor coil layer are insulated by insulating layers. The feature of the present invention is that the lower magnetic layer is a sendust film and the upper magnetic layer is a permalloy film.
The insulating layers located above and below the conductor coil layer are to be hard-baked resist films. The hard bake film of this resist is, for example, a novolac-based resist cured film.

The present invention is also a method of manufacturing such a thin film magnetic head. A sendust film is formed as a lower magnetic layer by a vapor deposition method or a sputtering method to form a lower magnetic layer of 450 to 500.
Annealing at ℃, then forming a gap film, providing a coil layer insulated by an insulating layer, heating the resist to be an insulating layer and performing a hard bake process, and further plating or sputtering a permalloy film as an upper magnetic layer. Formed by 300
Anneal at ~ 320 ° C. The hard bake temperature of the resist is set to 340 to 370 ° C. and 40 to 70 ° C. higher than the annealing temperature of the permalloy film.

[0010]

The sendust film is very similar to the permalloy film in terms of magnetic properties, but it is thermally stable and its annealing temperature is considerably high at 450 to 500 ° C. By using this sendust film as the lower magnetic layer, the heat treatment temperature of the hard bake film of the resist, which becomes the insulating layer thereabove, can be increased from 340 to 37
Even if the temperature is set to 0 ° C., the sendust film is not thermally adversely affected, and the resist is sufficiently heat-shrunk. The permalloy film of the upper magnetic layer provided thereon is 300 to 3
When annealed at 20 ° C., this temperature is lower than both of the heat treatment temperatures that have already been performed, so there is no adverse effect on the sendust film and the hard bake film of the resist, and the original good magnetic properties of the permalloy film are obtained. Is obtained. In the present invention, the lower layer film has a higher heat treatment temperature and the upper layer has a lower heat treatment temperature in sequence, so that thermal adverse effects on the already provided lower layer are avoided, and the necessary heat treatment is performed on each layer as a whole. It is possible to obtain good recording and reproducing characteristics.

[0011]

1 is a partial sectional view showing an embodiment of a thin film magnetic head according to the present invention. The ceramic substrate 10 that serves as a slider has an insulating layer 12 made of alumina formed on the surface for electrical insulation from the element. A sendust (FeAlSi) film to be the lower magnetic layer 14 is formed thereon. Then, the gap film 16 for ensuring the gap of the thin film magnetic head is provided. The gap film 16 is an alumina sputter film. Further, a conductor coil layer 18 is provided,
Insulating layers 20 and 22 are provided on the upper and lower sides to separate and insulate the conductor coil layer 18. Here, in order to simplify the drawing, the conductor coil layer is one layer, and therefore the insulating layer 22
-The structure of the conductor coil layer 18-insulating layer 20 is used. However, when a plurality of conductor coil layers are formed, the insulating layer and the conductor coil layer are repeatedly stacked. A permalloy (NiFe) film is formed thereon as the upper magnetic pole layer 24 by plating. Finally, an alumina film to be the processing protection layer 26 is formed on the upper magnetic layer 24.

Sendust (FeA) which becomes the lower magnetic layer 14
Since the (1Si) film cannot be formed by electroplating, it is formed by a vapor deposition method or a sputtering method. This sendust film is
For example, the composition is 85Fe: 5.4Al: 9.6Si. The formed sendust film is heated to 450 to 500 ° C. and annealed to obtain the necessary soft magnetic characteristics.

The upper and lower insulating layers 20 and 22 provided to separate and insulate the conductor coil layer 18 are hard bake films of resist (novolac-based resist hardened films), and at 340 to 370 ° C. which is optimum for this resist. It is heat-treated and heat-cured. FIG. 2 shows the relationship between the hard baking temperature and the heat shrinkage rate of the resist at that time. The shrinkage ratio is represented by the change in the resist film thickness before and after the heat treatment, and is defined by the following equation. Shrinkage (%) = 100 × (film thickness after heat treatment) / (film thickness before heat treatment) As is clear from FIG. 2, the heat treatment at the conventional temperature of about 300 to 320 ° C. does not reach the saturated state. Therefore, if it is subsequently subjected to a heat treatment, there is still a possibility of further shrinkage at that time. On the other hand, when the hard bake treatment temperature is 340 to 370 ° C., the shrinkage ratio almost reaches saturation, and even if it is subsequently heated, thermal shrinkage does not occur and a stable hard bake film is obtained.

A permalloy (NiFe) film is formed as an upper magnetic pole layer 24 on the hard-baked insulating layer 20 by electroplating. Permalloy film is, for example, 82.5
~ 83.5Ni: the balance Fe. The formed permalloy film is annealed at 300 to 320 ° C. to obtain desired soft magnetic characteristics.

FIG. 3 shows the relationship between the hard bake treatment temperature of the resist and the annealing temperature of the upper magnetic layer formed thereon. This shows the relationship with the hard bake temperature when the permalloy film was annealed at 300 ° C. In the present invention, the hard bake temperature of the resist is set to be 40 to 70 ° C. higher than the annealing temperature of the upper magnetic layer. This makes it possible to suppress the thermal contraction rate of the insulating layer to almost zero when the third heat treatment (annealing treatment of the upper magnetic layer) is performed. On the other hand, if the hard bake temperature is the same as the annealing temperature or the temperature is not more than 20 ° C. as in the conventional case, some degree of heat shrinkage occurs in the insulating layer during the third heat treatment, which is the soft magnetic property of the magnetic layer. It will lead to deterioration.

FIG. 5 shows the comparison result of the recording / reproducing characteristics of the thin film magnetic head. In the figure, the solid line shows the characteristics of the product of the present invention, and the broken line shows the characteristics of the conventional product. This shows the output voltage when reading and writing are repeated while changing the recording frequency, and the thin film magnetic head of the present invention has a larger output than the conventional thin film magnetic head and exhibits good recording and reproducing characteristics. I understand.

[0017]

As described above, the present invention uses the thermally stable sendust film for the lower magnetic layer and the permalloy film for the upper magnetic layer. Therefore, the heat treatment required for the insulating layer located between them is sufficient. Can be applied. Therefore, when the upper magnetic layer (permalloy film) is annealed as necessary, the resist hard bake film of the insulating layer is not thermally shrunk, and good recording and reproducing characteristics are produced.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an embodiment of a thin film magnetic head according to the present invention.

FIG. 2 is an explanatory diagram showing a relationship between an annealing temperature of a permalloy film and a coercive force.

FIG. 3 is an explanatory diagram showing a relationship between a resist hard baking temperature and a thermal shrinkage rate of the resist at that time.

FIG. 4 is an explanatory diagram showing the relationship between the heat shrinkage rate of the insulating layer after the third heat treatment with respect to the difference between the hard bake treatment temperature of the resist and the annealing treatment temperature of the permalloy film.

FIG. 5 is an explanatory diagram of a comparison result showing a relationship between an output voltage and a recording frequency.

[Explanation of symbols]

 10 Ceramics Substrate 14 Lower Magnetic Layer 16 Gap Film 18 Conductor Coil Layer 20, 22 Insulating Layer 24 Upper Magnetic Layer

Front page continued (72) Inventor Toshiharu Suzuki 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd.

Claims (3)

[Claims] 1. A structure in which a lower magnetic layer and an upper magnetic layer provided on a ceramic substrate are separated by a gap film, a conductor coil layer is provided between them, and the upper and lower sides of the conductor coil layer are insulated by insulating layers. In the thin-film magnetic head, the lower magnetic layer is a sendust film, the upper magnetic layer is a permalloy film, and the insulating layers above and below the conductor coil layer are hard-baked resist films. 2. The thin film magnetic head according to claim 1, wherein the hard bake film of the resist is a novolac-based resist cured film. 3. A lower magnetic layer on a ceramic substrate,
In a method of manufacturing a thin film magnetic head in which a gap film, a coil layer having upper and lower insulation layers insulated by an insulating layer, and an upper magnetic layer are formed in that order, a sendust film is formed as a lower magnetic layer by an evaporation method or a sputtering method. Annealing is performed at 450 to 500 ° C., then a gap film is formed, a coil layer insulated by an insulating layer is provided, and a resist serving as an insulating layer is heated and hard baked, and a permalloy film is plated as an upper magnetic layer. Alternatively, it is formed by a sputtering method and is 300 to 320.
A method of manufacturing a thin film magnetic head, characterized in that annealing treatment is performed at a temperature of ℃, and the hard bake temperature of the resist is set to 340 to 370 ℃ and 40 to 70 ℃ higher than the annealing temperature of the permalloy film.