JPH06176318A - Coil formation of thin-film magnetic head - Google Patents

Abstract

PURPOSE:To provide the process for production which forms coils of a high- density and low resistance by insulating coils from each other with org. or inorg. insulating films in the process for production of the thin-film magnetic head. CONSTITUTION:After the first coil 7 of a relatively small film thickness electrically connected at least at one point to the circumference is formed on the first insulating layer 1, the second insulating layer 9 consisting of the org. or inorg. material is formed between coil conductors. The second coil 10 of a relatively large film thickness is formed by plating on the second insulating layer 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film magnetic head adapted for high density recording, and more particularly to a method of forming a high density and low resistance coil between an upper magnetic core and a lower magnetic core. is there.

[0002]

2. Description of the Related Art FIG. 5 shows, for example, JP-A-55-84019.
FIG. 5 shows a coil forming method using a pattern plating method in the conventional thin film magnetic head shown in Japanese Patent Publication No.
As shown in (a), a plating underlayer 2 is formed on the insulating layer 1 formed on the lower magnetic core by sputtering or the like, and the portion other than the coil forming portion on the plating underlayer 2 is photoresist by photolithography. It is covered with (coil gap insulating layer) 3.

Next, as shown in FIGS. 5 (b) and 5 (e), the coil forming portion is electroplated to form the coil 4. Next, after removing the photoresist 3 as shown in FIG. 5C, the plating underlayer 2 in the gap between the coils 4 is removed by etching with Ar ions as shown in FIG. 5D. At this time, since ion etching is performed without a mask, the coil 4 also has substantially the same film thickness (about 10
0 nm) is etched.

FIG. 6 shows a coil forming method by etching in another conventional thin film magnetic head.
As shown in (a), a coil conductor film 5 is formed on the insulating layer 1, and a photoresist 6 is coated on the coil conductor film 5 in a coil conductor shape by photolithography. Next, FIG.
As shown in FIGS. 6B and 6D, the photoresist 6
Using the as a mask, unnecessary portions of the coil conductor film 5 are removed by etching to form the coil 4. As the etching means, ion etching with Ar without under-etching is used. Next, as shown in FIG. 6C, the photoresist 6 is removed.

On the coil 4 formed as shown in FIG. 5 and FIG. 6, in order to electrically insulate the coil 4 and the upper magnetic core formed on the coil 4 and to flatten the unevenness due to the coil 4. Then, an insulating layer is formed. This flattening is
It is necessary in order not to deteriorate the magnetic characteristics of the upper magnetic core formed on the upper side.

As the insulating layer for this flattening, an organic resin film such as photoresist or polyimide, or SiO
An inorganic insulating film such as ₂ or Al ₂ O ₃ is used. In the case of an organic film, it is spin-coated, and the fluidity thereof fills the space between the conductors of the coil 4 to flatten it. In the case of an inorganic film, it is formed by sputtering or a CVD method, and the unevenness of the coil 4 is transferred almost as it is. So coil 4
The thickness of the inorganic film is made thicker than the thickness of, and mechanical polishing or etch back (resist is applied, and ion etching is performed under the condition that the etching rate of the resist and the inorganic film are equal, and the shape of the resist is transferred to the inorganic film. )It is carried out. As described above, an inorganic film requires a complicated process for flattening as compared with an organic film, but since it has high heat resistance, it has a high Bs by heat treatment.
It is used for a magnetic head having a magnetic core made of a high Bs magnetic material that can obtain various magnetic properties, and the magnetic head is heat-treated at a temperature of 400 ° C. or higher. Organic resin cannot be used because it causes thermal decomposition when used in a magnetic head that is heat-treated.

[0007]

By the way, in order to increase the density of magnetic recording, the coil 4 of the thin-film magnetic head is required to have high density and low resistance. That is,
In high-density recording, the signal magnetized area on the recording medium becomes smaller, so it is necessary to perform reproduction efficiently. In order to reduce magnetic flux leakage, the magnetic path length of the magnetic core is made small and the reproduction output is made high. Since it is necessary to wind the coil 4 many times, it is necessary to increase the density of the coil 4. Further, in order to reduce noise during reproduction and suppress heat generation during recording, it is necessary to reduce the resistance of the coil 4.

In order to make the coil 4 wound many times and have a low resistance at the same time, the coil 4 may be stacked in multiple layers with an insulating layer interposed therebetween. In order to achieve the purpose of winding and increasing the cross-sectional area (coil width x height) of the coil 4 to reduce the resistance of the coil 4, the gap between the coils 4 is made small and the height of the coil 4 is made high. Is advantageous.

However, in the above-described conventional coil forming method, it is difficult to form the coil 4 in which the gap between the coils 4 is small and the height of the coil 4 is high.
First, in the coil forming method by the pattern plating method shown in FIG. 5, it is possible to narrow the gap of the coil 4 in the steps up to FIG. 5B by using the photolithography technique. But,
Maskless ion etching utilizing the film thickness difference is used when removing the plating underlayer 2 in the gaps between the coils 4, and since the gaps between the coils 4 are deep valleys, it is difficult for ions to enter that portion. Since the time required for removing the plating underlayer 2 is several times as long as that for etching the flat portion, the thickness of the underlayer 2 with the coil 4 being sharp while the plating underlayer 2 is removed. There was a problem that it was etched about several times.

Further, a method of previously forming the plating base layer 2 by limiting it to only a necessary portion (Japanese Patent Publication No. 47040/1990).
However, for example, a standard spiral coil 4 of a thin film head having a coil width of 4 μm, a gap between the coils of 1 μm, and a coil inner diameter (radius) of 30 μm has a resistance of 100Ω.
The thickness of the plating increases, and the plating preferentially adheres to the part where the resistance is low and the current easily flows.
There is a problem that the plating film thickness becomes thin in the portion far from the current terminal.

Next, in the coil forming method by etching shown in FIG. 6, it is possible to coat the photoresist 6 with a coil conductor shape by photolithography as shown in FIG. 6 (a). However, in the ion etching of the coil conductor film 5, the etching rate of the coil conductor film 5 decreases in the deep valley portion between the photoresists 6,
Further, the etched coil conductor film material adheres (reattaches) to the side wall of the coil 4, and further, the end face of the photoresist 6 recedes and the like, whereby the upper part of the coil 4 is thinned and the cross-sectional area of the coil 4 is reduced. It was Since this tendency becomes more remarkable as the aspect ratio is increased, it is difficult to form the coil 4 having a narrow gap and a high height by this method.

Further, when the width of the gap between the coils 4 becomes narrow, there is a problem that the insulating film is not completely filled in the deep valley. That is, when the insulating film is an inorganic film, it is formed by bias sputtering or a CVD method, but since the probability of particles reaching the deep valley is smaller than that in other areas, it is easy for the blind to form in this area. The screen became the cause of film peeling in the later process. Further, when the insulating film was an organic film, air was apt to remain in this portion during spin coating, and foaming occurred during the heat treatment for drying the film. This tendency became more remarkable as the aspect ratio was increased.

As described above, the conventional coil forming method has a limitation in increasing the density of the coil 4, and along with the increase in the Bs of the core material, one of the important problems to be solved in the future for high density magnetic recording. For example, in the current situation, if the gap between the coils 4 is set to about 1 μm, the height of the coil 4 is 4 μm in the case of an organic insulating film, and the height of the coil 4 is about 3 μm in the case of an inorganic insulating film. It is the limit. Therefore, regardless of which insulating layer is used, it is desirable that the gap between the coils 4 be 1 μm and the height of the coils 4 be about 6 μm. In particular, raising the coil 4 is effective because the resistance is inversely proportional to the film thickness. Is big.

The present invention has been made to solve the above problems, and can use either organic or inorganic as an insulating film on the coil 4, and the coil has a high density and a low resistance. It is an object of the present invention to obtain a method for forming a coil of a thin film magnetic head capable of forming No.

[0015]

According to a first aspect of the present invention, there is provided a coil forming method for a thin-film magnetic head, wherein at least one outer peripheral conductive portion is formed on the first insulating layer formed on the lower magnetic core. A step of forming a first coil electrically connected and having a thickness smaller than a predetermined thickness; a step of forming a second insulating layer made of inorganic or organic in a gap between the first coils; A step of forming a relatively thick second coil by plating is provided on the first coil using the insulating layer as a mask.

Further, in the coil forming method of the thin-film magnetic head according to the second aspect, the electrical connection with the outer peripheral conductive portion of the first coil is performed through the conductor provided in advance under the first insulating layer. It is a thing.

[0017]

According to the first aspect of the present invention, after the first coil having a relatively small thickness is formed, the second insulating layer made of inorganic or organic is formed in the coil gap, which facilitates the formation of the second insulating layer. Becomes In addition, a second coil having a relatively large thickness is formed on the first coil by plating using the second insulating layer as a mask.

Further, in the present invention, the electric connection with the outer peripheral conductive portion of the first coil is made through the conductor provided under the first insulating layer, and the plating of the second coil is performed. At the time of formation, the first coil serves as a good current path, and the second coil is accurately formed.

[0019]

【Example】

First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the drawings, the magnetic core, the substrate, the protective layer, etc. are omitted to clarify the main points, and only the coil portion is shown. FIG. 1 shows a manufacturing process of a coil of a thin film magnetic head, (a) to (c) are sectional views, and (d) and (e) are plan views.

First, in FIG. 1A, 1 is a first insulating layer formed on a lower magnetic core (not shown),
A spiral 10-turn first coil 7 made of Cu having a film thickness of 2 μm, a width of 4 μm, and a gap width of 1 μm is formed on the first insulating layer 1 by the pattern plating method shown in FIG.
The resistance of the first coil 7 is about 9Ω. First coil 7
In order to secure a current path for plating, as shown in FIG.
Is connected to the plating base layer (conductive portion) 2 on the outer periphery of the outer periphery. Therefore, in the pattern plating method, the plating base layer 2 around the outer periphery of the connecting pattern 8 is left without being removed.

Next, 4.5 μm from the surface of the first coil
After spin-coating a second insulating layer 9 of photoresist having a thickness of (thus having a thickness of 6.5 μm from insulating layer 1) on the second insulating layer as shown in FIG. The same coil pattern as that of the first coil 7 is formed on the coil 9. The superposition accuracy at this time is sufficient to be about 0.5 μm, and it is sufficient that the formed coil does not short-circuit. Although this coil pattern is not connected to the plating base layer 2 on the outer periphery as shown in FIG. 1 (e), it may be connected as shown in FIG. 1 (d).

Next, as shown in FIG. 1 (c), the coil pattern formed between the second insulating layers 9 has a thickness of 4 .mu.m.
The second coil 10 is formed by performing u plating. The first and second coils 7 and 10 have a thickness of 6 μm and a width of 4 μm.
m, a gap of 1 μm and a resistance of about 3Ω are formed. However, it has unevenness of 0.5 μm with the second insulating layer 9. In practice, the width of the second insulating layer 9 is 0.6-0.
It becomes smaller than 8 μm and 1 μm, and the upper part has a narrowed shape. This is due to the difference in the time of exposure of light during exposure and the difference in time of contact with the developing solution. Further, since these values differ depending on the exposure apparatus, it is necessary to experimentally determine the optimum conditions.

By applying a photoresist insulating film on the coils 7 and 10 formed as described above, 0.5
The μm recess is flattened. Similarly, the coils of the second and third layers can be formed. Connecting pattern 8
Are removed after formation of the final coil (except for Example 1
Then you can leave it. ).

Although the photoresist is used as the second insulating layer 9 in the first embodiment, the same effect can be obtained by using a photosensitive material such as a photosensitive polyimide resin or a photosensitive silicone resin. Further, the gap width between the first coils 7 which functions as a plating base when forming the second coil 10 may be the same as or different from the gap width between the second coils 10, but it can be said that If it is larger, As described above, in Example 1, first, the first coil 7 having a relatively thin film thickness is formed, the second insulating layer 9 between the coils is formed at this stage, and then the second insulating layer 9 is formed. Is used as a mask and the second coil 10 is plated with the first coil 7 as a plating base, so that the gap width between the coils 7 and 10 can be made small and the coil thickness can be made large. A coil with high density and low resistance can be formed.

Embodiment 2 FIG. 2 is a sectional view showing a coil forming method according to Embodiment 2, and a plan view thereof is the same as that of Embodiment 1 and therefore omitted. First, as shown in FIG. 2A, a spiral 10-turn first coil 7 made of Cu having a film thickness of 2 μm, a width of 4 μm, and a gap of 1 μm is formed on the insulating layer 1 by a pattern plating method. At least one location of the first coil 7 is connected to the plating base layer 2 left on the outer periphery through the connecting pattern 8. Next, on the first coil 7, in place of the second insulating layer 9 made of the photoresist of Example 1, Al having a thickness of 4 μm was used.
The second insulating layer 11 made of a ₂ O ₃ film is formed by sputtering, and then a Cu film is deposited to 2000 Å in the same vacuum chamber.
To form a Cu mask 12 by ion beam etching this Cu film by photolithography. This Cu
The mask 12 is formed on the concave portion corresponding to the gap between the first coils on the second insulating layer 11, and since the photoresist is easily accumulated in the concave portion and becomes thick, a semi-self alignment effect is obtained. Increases the alignment margin. That is, even if the position of ion beam etching of the Cu film is slightly deviated, the thick resist portion is likely to remain because the dissolution time becomes long during development.

Next, as shown in FIG. 2B, the second insulating layer 11 is anisotropically dry-etched with a Freon gas by using the Cu mask 12 as a mask to expose the first coil 7. , The first coil 7 by switching the gas to Ar
The deteriorated layer and the Cu mask (having a film thickness of 1000 Å or less due to the sputtering effect during dry etching) 12 on the surface of are removed.

Next, as shown in FIG. 2 (c), the second insulating layer 11 is used as a mask and the first coil 7 is used as a plating base to perform Cu plating with a thickness of 4 μm.
To form. Here, when the thickness of Cu plating becomes too thick and the adjacent coils 10 are short-circuited, the short-circuited portion is removed by Ar ion beam etching.

In this way, the second insulating layer 11 having a thickness of 1 μm can be formed in the gap between the plurality of coils 7 and 10 to form the flat coils 7 and 10 having a thickness of 6 μm. In addition,
In the second embodiment, the second insulating layer 11 is made of inorganic material Al ₂ O.
_Three films were used, but SiO ₂ , Si ₃ N ₄ , SiC, Si
Even if an inorganic film such as AlON or an organic resin such as a polyimide resin or a ladder silicone resin (in this case, oxygen can be used as an etching gas for anisotropic dry etching), low resistance and high resistance can be similarly obtained. Density coils can be formed. Also, instead of the Cu mask 12,
A material having resistance to Freon-based gas, such as Ni, can be used.

Embodiment 3 In Embodiments 1 and 2, the first method is used to secure the plating current path.
Although one part of the coil 7 was connected to the surrounding plating base layer 2 via the connecting pattern 8, in Example 3, the first insulating layer 1 was provided below the first coil 7 as shown in FIG. Conductors 13 are arranged, through holes are provided in the first insulating layer 1, and the first coil 7 is provided with a central portion (center butt portion) 7
Electrical connection is made at two points, a and the end portion 7b. In this case, the resistance of the first coil 7 is about half, about 5Ω.
Further, when the coil has a laminated structure of two or more layers, the same resistance reduction effect is obtained for the coils of each layer.

In the third embodiment, since both ends of the first coil 7 are connected to the current path, the second coil 10
Both ends of the first coil 7 have to be separated from the current path after the formation of the wiring, and the connecting pattern 8 needs to be removed. Although the coils 7 and 10 are of spiral type, they have a great effect even in the case of a helical type, and in particular, the helical type has an advantage that many current contacts can be taken.

Fourth Embodiment FIG. 4 is a plan view showing a coil forming method according to a fourth embodiment. In the fourth embodiment, a conductor 13 group is arranged below a first coil 7 with a first insulating layer 1 interposed therebetween. Through holes 14 are provided in the first insulating layer 1 to connect the first coil 7 and the conductor 13 group at a plurality of points. This connection point is through hole 14
In addition to being able to take a large area, the magnetic core is provided in the back core portion having no magnetic core in the lower part in order not to increase the magnetic path length, but the present invention is not limited to this.

In each of the above-mentioned embodiments, since the film thickness of the first coil 7 is relatively thin, 2 μm or less (preferably 0.3 μm or more), an accurate one can be formed. When the pattern plating method is used for this formation, the plating base layer 2 is removed by ion etching. Then the first
Although the second insulating layers 9 and 11 are formed in the gap between the coils 7 of the above, since the film thickness of the first coil 7 is relatively thin, the second insulating layers 9 and 11 are not covered with the blinds.

Further, in forming the second coil 10,
Pattern plating is performed using the second insulating layers 9 and 11 as a mask, but since the plating base layer 2 has already been removed,
The second insulating layers 9, 11 can be left as they are. The first coil 7 functions as a plating base when the second coil 10 is formed. However, when the film thickness is as thin as 0.1 μm, the central portion (the portion far from the peripheral plating electrode) is formed. 2) becomes high (about 200Ω with a standard 10-turn spiral coil having a film thickness of 4 μm, a gap of 3 μm, and an inner diameter of 50 μm), which causes a problem that plating is not uniformly applied. Therefore, it is necessary to select the thickness of the first coil 7 according to the number of coil turns and the width (thicker as the number of turns is larger and the width is smaller), and about 0.3 to 2 μm is suitable. If the film thickness is thin, the resistance increases and the film thickness distribution during plating becomes large. If it is too thick, it becomes difficult to reduce the gap. Therefore, the important point when forming the first coil 7 is to make the resistance of the coil as low as possible without making the coil thickness too thick, and to secure the current path at the time of plating, at least one place is for the surrounding plating. It is to be electrically connected to the base.

When forming the second coil 10, a pattern for the thick film coil (approximately the same shape as the first coil 7) is formed by photolithography. At this time, the overlay accuracy is important, but it is within a range where a sufficient margin can be taken with the current photoengraving accuracy. Then, the second coil on the first coil 7
The insulating layers 9 and 11 are etched and Cu is plated on the exposed first coil 7. In this case, if the thickness of the Cu plating is set to be the same as that of the second insulating layers 9 and 11 (actually, the second insulating layer 9 and
The thickness of 11 is set. ), A flat coil can be formed. The thickness of the second coil 10 is set to 2 μm or more, and the total film thickness of the coil is set to 2.3 to 4 μm or more.

In each of the above embodiments, only the coil portion is shown for the sake of clarity, but in an actual thin film magnetic head, the coil is arranged above or below the gap surface. For example, when the coil is provided in the concave portion and the inorganic film is used as the inter-coil insulating layer, the coil interval cannot be narrowed because the film is simply formed by sputtering in the related art, and it is troublesome to flatten the unevenness of the coil by etching back or polishing. Although a means was required, in each of the above-mentioned embodiments, a coil interval is small and a coil having a large film thickness can be formed. Further, if necessary, by repeating the same process on the formed coils 7 and 10 using this as a plating base, the coil thickness can be further increased. In this case, if the coil thickness is kept at a position slightly lower than that of the second insulating layers 9 and 11, the semi-self alignment effect of the second embodiment works and the overlapping margin can be expanded. As the coil material, a metal such as Au which has low resistance and can be plated may be used other than Cu.

[0036]

As described above, according to the first aspect of the present invention, since the second insulating layer is formed at the stage when the first coil having a relatively small film thickness is formed, the second insulating layer is formed. The layer is easy to form, and the second coil is formed by plating with the first coil as the plating base using the second insulating layer as a mask, and the gap width between the coils is reduced, and
The coil height can be increased, and a high density and low resistance coil can be obtained. Further, since either an organic film or an inorganic film can be used as the second insulating film, a high Bs magnetic material requiring heat treatment can be used for the magnetic core.
Further, since the formed coil is flattened by itself, it is easy to increase the output by increasing the number of coil turns by stacking or multi-layered coils, and it is an efficient thin film magnetic suitable for high density recording. The head coil can be stably formed.

According to the second aspect, the first coil is electrically connected to the surroundings through the conductor provided under the first insulating layer, and when the second coil is formed. The resistance of the first coil that serves as a current path in plating can be reduced, and the second coil can be formed with high accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view and a plan view showing a coil forming method according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a coil forming method according to a second embodiment of the present invention.

FIG. 3 is a plan view showing a coil forming method according to a third embodiment.

FIG. 4 is a plan view showing a coil forming method according to a fourth embodiment.

5A and 5B are a cross-sectional view and a plan view showing a conventional coil forming method.

6A and 6B are a sectional view and a plan view showing another conventional coil forming method.

[Description of Reference Signs] 1 first insulating layer 2 plating underlayer 7 first coil 9, 11 second insulating layer 10 second coil 13 conductor

Claims (2)

[Claims] 1. A method of forming a coil of a thin-film magnetic head, wherein a coil made of a conductive material is narrowly provided between an upper magnetic core and a lower magnetic core, and a step of forming a first insulating layer on the lower magnetic core, Forming a first coil having a relatively small thickness electrically connected to the outer peripheral conductive portion at least at one location on the first insulating layer; and forming a gap between the first coils from inorganic or organic. A thin film comprising: a step of forming a second insulating layer; and a step of forming a second coil having a relatively large thickness on the first coil by plating using the second insulating layer as a mask. Method for forming coil of magnetic head. 2. The thin film magnetic head according to claim 1, wherein the first coil and the outer peripheral conductive portion are electrically connected to each other through a conductor provided in advance under the first insulating layer. Coil forming method.