JPS63152010A - Production of thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain an even upper insulation layer having a few gaps where it is not easy that blowholes remain by forming a groove corresponding to the width of a coil, the height of a coil and the space between coils on a lower insulation layer and applying the upper insulation layer on an outer surface which is even by forming a coil in the groove. CONSTITUTION:A lower insulation film 2 is formed in a specified film thickness on a substrate 1 and a photoresist pattern 3 is formed on the surface of the film 2, then the groove with the specified shape and dimension corresponding to the coil is formed on the lower insulation film 2 in a drying method. And an activating process which is the pre-processing of non-electrolytic plating is executed but a film 4 obtained with the activating process remains only on the inner wall of the groove by removing the photoresist pattern 3. A plated film 5 as a coil grows on the inner wall of the groove and fills the inside of the groove. Therefore, the heights between the upper surface of the coil 5 and the coil become almost equal after forming the coil and the upper insulation layer 6 is formed on the said surface. Thus, in case of forming the upper insulation layer 6 in subsequent processes, the blowholes do not remain and the outer surface of the upper insulation layer 6 becomes almost even.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a thin film magnetic head, and particularly to a method for manufacturing a thin film magnetic head suitable for forming a coil and an insulating film of the thin film magnetic head.

[Conventional technology]

In magnetic recording, thin film magnetic heads are used to increase pit density and track density to increase recording density. FIG. 4 shows a typical configuration diagram of a thin film magnetic head using a single-layer spiral multi-turn coil. The same figure (,) is a front view, and the same figure (b) is an enlarged view of the AA cross section of (,). The coil 20 has a spiral shape, and both ends thereof are connected to an external electric circuit via coil lead-out terminals 25.

This coil 20 is interlinked with a magnetic circuit consisting of a lower magnetic film 21, an upper magnetic film 23, and a gap insulating layer 22. During writing, a locking signal current flows through the coil 20 via the coil lead-out terminal 25 to generate a magnetic field according to the writing signal. Then, the magnetic film 21 .near the coil 20 .
Although magnetic flux is generated in the air bearing surface 23, magnetic flux is generated in the vicinity of the gap, which is the opening of the magnetic circuit, and magnetic flux is applied to the magnetic medium facing the gap via the air bearing surface 24. On the other hand, during reading, the magnetic flux recorded on the magnetic medium and leaking is transferred to the air bearing surface 2.
4, the magnetic circuit passes through the magnetic circuit, and an induced current flows through the coil in response to changes in magnetic flux.

FIGS. 5(1) to 5(7) show the conventional manufacturing process of such a single-layer snoiler multi-turn coil. First, a lower magnetic pole 21 is formed on a substrate 1, a gap insulating layer 22 for forming a head gap is provided on the lower magnetic pole 21, a lower insulating layer 2 is overlaid, and a coil 20 is patterned. The upper magnetic pole 23 is formed after the upper magnetic pole 23 is wrapped with the upper insulating layer 6. (See Nikkei Electronics, July 7, 1980 issue, pages 110-111.

) Hardened photoresists have been used as the insulating layers 2 and 6 used for electrical insulation between the coil 20 and the magnetic poles 21 and 23.

However, photoresists have a problem of poor heat resistance. Therefore, in order to improve heat resistance, examples of using polyimide resin in the insulating film are IEE, TrumpKushion Magnetics, and MNG1.
5 (1979) pp. 1616-1618 (1,
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Film H@ad').

[Problem that the invention seeks to solve]

In order to perform high-density recording, it is necessary to increase the number of turns in the coil and reduce the dimensions of each head. Therefore, the number of coils and coil gaps increases, and the coil width and spacing between the coils decreases. The above-mentioned photoresist and polyimide resin are both coated, but when the coil spacing becomes narrow, air bubbles are easily removed when coating the upper insulating layer, and air bubbles tend to remain in the upper insulating layer, causing magnetic There was a problem that the reliability of the head decreased.

Furthermore, conventionally, since the upper insulating layer is coated and filled over the portion where there is a height difference between the upper surface of the coil and the coils, the outer surface of the formed upper insulating layer has large irregularities. If the upper magnetic film is formed on this highly uneven surface, the film thickness will vary greatly, the film thickness will not be uniform, and the characteristics of the magnetic head will deteriorate. Therefore, conventionally, a step of planarizing the outer surface of the upper insulating layer was required, which complicated the process and worsened economic efficiency.

An object of the present invention is to provide a method for manufacturing a thin film magnetic head in which there are no residual bubbles and the outer surface of the upper insulating layer is flat.

[Means for solving problems]

The above purpose is to form a groove in the lower insulating layer corresponding to the coil width, coil height, and coil spacing, form the coil in the groove, and then apply the upper insulating layer on the flat outer surface. Most of all, it will be achieved.

[Effect]

First, a lower insulating layer with a flat outer surface is formed.

Subsequently, grooves corresponding to the coil width, coil height, and coil spacing are formed on the outer surface of the lower insulating layer. A coil is formed within the groove. After the coil is formed, the upper end of the coil and the outer surface of the external insulating layer are almost on the same plane. A top insulating layer is applied on this flat outer surface.

Since the upper insulating layer is formed on this flat surface, an upper insulating layer with few voids is obtained since no air bubbles remain during coating, and the outer surface of the upper insulating layer is flat.

〔Example〕

FIGS. 1 (1) to (7) show the manufacturing process of the insulating layer and coil of the present invention. For convenience of explanation, the magnetic film and the like formed on the substrate are included in the substrate 1 in the drawings, and only the conductor coil and the insulating layer in which the conductor coil is embedded are shown.

In step (1), a lower insulating film 2 is formed to a predetermined thickness on a substrate 1.

In step (2), seven photoresist patterns 3 are formed on the surface of the lower insulating film 2.

In the step (3), a groove having a predetermined shape and size corresponding to the fill is formed in the lower insulating film 2 by a dry method using the photoresist layer and the turn 3 as a mask.

In step (4), an activation treatment is performed as a pretreatment for electroless plating. The coating 4 resulting from the activation treatment is formed not only on the inner wall of the groove but also on the surface of the photoresist gloss turn 3.

In step (5), photoresist l? Remove turn 3. The activation treatment film 4 formed on the photoresist pattern 3 is also removed at the same time.

That is, the coating 4 resulting from the activation treatment remains only on the inner wall of the groove.

In step (6), it is immersed in a chemical plating solution to form a conductor plating film 5 as a coil. Since the activated film 4 exists only on the inner wall of the groove, the plated film 5 grows on the inner wall of the groove and fills the inside of the groove. Therefore, after the coil is formed, the heights of the upper surface of the coil 5 and the portion between the coils are approximately the same.

In step (7), the upper insulating layer 6 is formed on the surface at the same height.

As mentioned above, after the coil formation in step (6) is completed, the heights of the coil 5 and the part between the coils are almost the same and have a flat outer surface, so the subsequent step 7) In the step of forming the upper insulating layer 6, no air bubbles remain, and the outer surface of the upper insulating layer 6 becomes substantially flat.

Next, an embodiment of the present invention will be described using FIG. 2. Second
Figures (1) to (3) show the process of using polyimide resin, which is an organic resin, as an insulating film on the substrate 11 and forming grooves thereon by a dry method.

Examples of the dry method here include plasma etching and ion beam etching, but these methods can narrow the width of the 4-turn groove and create a high density, compared to the method of forming grooves by chemical etching using a solution. It has the feature of being able to form grooves for conductor coils.

In FIG. 2(1), a polyimide resin 12 is formed on a substrate 11, and then, as shown in FIG. 2(2), a 7-photoresist/g turf 13 is formed. As the photoresist used here, a novolac positive type photoresist can be used because it has good pattern accuracy. The cross-sectional shape of this photoresist or turn becomes a wider trapezoid when it is closer to the polyimide resin.

Using the thus formed photoresist) turn t4 as a mask, the polyimide resin 12 is etched by a dry method as in (3). As for the etching method at this time, ion beam etching using 02 gas has good pattern accuracy and allows stable etching. At this time, the polyimide resin film is etched and at the same time the photoresist used as the mask material is also etched.
The height and width are reduced according to the etching. Since both photoresist and polyimide resin have almost the same etching speed, the initial film thickness of the photoresist is formed to be thicker than the depth of the groove in the polyimide resin, so that the photoresist remains on the polyimide resin even after ion beam etching. .

Next, as shown in FIG. 2 (4), activation treatment is performed as a pretreatment for electroless plating.

For example, after soaking the substrate in a solution of 5nC12-2H20409/I HCt20 rat/1 for 2 minutes, PaCl2-2
In a solution of H200, 41/l HCl 4 ml/1,
By inserting the entire board for 2 minutes! D. As shown in (4), Pd is deposited on the entire surface of the substrate, and electroless plating is activated.

Next, as shown in Fig. 2 (5), the photoresist is removed and, at the same time, the Pd on the photoresist is removed so that the activated film remains only inside the grooves of the polyimide resin. .

Next, as shown in (6), by placing this substrate in an electroless plating solution, a metal film as a coil conductor is selectively deposited inside the activated groove. Then, an insulating layer is applied on top of this. (7) represents the state when the coating of the upper insulating layer is completed.

As the metal to be precipitated by the above activation treatment, other than Pd, Au, Ag, Pt, etc. can be used. In particular, to improve the heat resistance of polyimide resin, Au
, Pt, and other metals are desirable.

In addition, as an activation treatment method, a method using a solution is described.
It is also possible to adopt a method in which after forming on the entire surface of the substrate as shown in 4), the 7 photoresist is removed as shown in (5) and the activated metal film remains only inside the groove.

According to this method, instead of depositing only one type of metal, it is possible to stack two or more metal films to form an activated film, and it is also possible to form a thick film of 10 nm or more. Since it is easy, by leaving this activated film, it is possible to prevent the polyimide resin from reacting with the metal of the conductor coil, such as Cu, and thereby deteriorating its heat resistance.

As the metal film of the conductor coil, it is desirable to select a metal with low resistivity such as Cu or Au.

The aforementioned metal film as a coil conductor and j? Another method to prevent heat resistance deterioration of polyimide resin due to reaction with IJ imide resin is to apply a plating film as a reaction prevention layer before forming an electroless plating film directly in the activated groove. It is possible to adopt a method of forming an electroless plated film after forming the film in advance. When Cu is used as a metal film as a conductor pattern, N1 is used as a reaction prevention layer.
, Au, Pt, etc., which are less reactive than Cu, are used.

In addition, when forming polyimide resin on the conductor coil,
If it is formed directly on the conductor coil, there is a problem that the conductor coil and polyimide resin come into direct contact and the heat resistance of the polyimide resin deteriorates, so the conductor coil is plated and a reaction prevention layer is provided on the conductor coil after death. Especially,
It is possible to prevent deterioration of heat resistance. That is,
After forming the conductor coil 15 according to the steps shown in FIG. 2 (1) to (5), the conductor coil 15 is formed as shown in FIG. 3 (6).
A reaction prevention layer 7 is formed on the upper outer surface of 5, followed by application of an insulating layer. FIG. 3 φ) shows the state when the coating of the upper insulating layer 6 is completed. Therefore, the structure is such that the coil is wrapped in a reaction prevention layer.

When a plating film is formed in the groove formed in the polyimide resin, it is preferable that the height of the plating film be approximately the same as the surface of the polyimide resin. In this way, when forming the polyimide resin film on the upper part, the unevenness on the coated surface can be reduced, so that the unevenness on the surface of the polyimide resin formed on the upper part can be made small and smooth.

In the above embodiments, polyimide resin was used as the insulating film, but other organic resins may be used as the insulating film depending on the usage conditions. That is, a cured photoresist film can also be used as the insulating film as in the conventional example.

In the above embodiments, the conductor coil was formed by electroless plating, but after activation treatment, it is used as a base film for a thin film for electroplating after death. It is also possible to form a conductor coil by electroplating by using an electroless plated film formed in the same manner and by making an electrical connection.

〔Effect of the invention〕

According to the present invention, a high-density conductor coil is placed between air bubbles and
It is possible to completely fill the insulating film with no voids, and the surface of the insulating film formed on the coil can be made flat with almost no unevenness, improving the characteristics of thin-film magnetic heads.
It is possible to improve reliability.

[Brief explanation of the drawing]

Figures 1 (1) to (7) are cross-sectional views showing the steps of the present invention, Figures 2 (1) to (7) are cross-sectional views showing the steps of the embodiment of the present invention, and Figure 3 is 4(a) and 4(b) are front views and AA sectional views of the thin film magnetic head, and FIGS. )
1 is a cross-sectional view showing a back manufacturing process of a conventional thin film magnetic head. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Lower insulating film, 3...
...Photoresist, 4. Film formed by activation treatment, 5. Coil conductor, 6. Upper insulating film, 7.
...Reaction prevention layer. ,'-] Agent Honda Kohira -7-)] Kota Tani,--j
Screen 13--Photoresist Fig. 2--Reaction prevention layer B--Gap insulation 1 25--Coil drawer screw Fig. 5 1-Substrate 2-Lower rectangle @ 20-Coil one substrate 2-Bottom Insulation n cost 6- Coil--・-Uman insulating film

Claims (1)

[Claims] 1. A method for manufacturing a thin film magnetic head in which a conductor coil having a plurality of turns is surrounded by a lower insulating film and an upper insulating film, the method comprising forming the conductor coil inside the lower insulating film. 1. A method of manufacturing a thin film magnetic head, comprising: forming a groove, forming a conductor coil in the groove, and then forming an upper insulating film on the conductor coil and the lower insulating film. 2. The method of manufacturing a thin film magnetic head according to claim 1, wherein the groove in the lower insulating film and the conductive coil are formed so that the upper surface of the conductor coil and the upper surface of the lower insulating film are on the same plane. 3. The method of manufacturing a thin film magnetic head according to claim 1 or 2, wherein an activated film is previously formed only on the inner surface of the groove, and then the conductor coil is formed in the groove by electroless plating. . 4. The method according to claim 3, wherein the activated film is formed thickly, thereby separating the insulating film and the conductor coil to prevent a reaction between the insulating film and the conductor coil. A method for manufacturing a thin film magnetic head. 5. The thin film according to claim 3, wherein after forming the activation treatment film, plating a metal film as a reaction prevention layer between the insulating layer and the conductor coil, and then forming the conductor coil by electroless plating. A method of manufacturing a magnetic head. 6. The thin film magnetic head according to any one of claims 3 to 5, characterized in that a reaction prevention layer is provided on the surface of the conductor coil after the conductor coil is formed by electroless plating. manufacturing method.