JPH08321012A - Thin film magnetic head and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] In a thin film magnetic head for bonding a protective substrate, the bonding strength is secured even if the bonding area is made small, providing a highly reliable and inexpensive small thin film magnetic head, and further improving the productivity. A method of manufacturing a thin film magnetic head having high efficiency is provided. A fine groove 7 filled with an adhesive, which is not exposed to the medium sliding surface in the vicinity of the medium sliding surface, is formed on the bonding surface of the protective layer 3 or the protective substrate 4, and a pattern forming and etching technique using a photoresist is performed. By arranging with the use of, the deterioration of the adhesive strength due to the decrease of the adhesive area due to the miniaturization of the magnetic head is prevented.

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 used in a magnetic recording / reproducing apparatus and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, a thin track magnetic head and a multi-channel thin film magnetic head have become necessary as the recording density becomes higher. In particular, with the digitization of audio and video products, thin-film magnetic heads are about to enter the consumer equipment field, and there is an urgent need to reduce costs and improve reliability over a long period of time. In particular, a thin film magnetic head in which thin films are stacked on a ceramic substrate having excellent wear resistance to form a magnetic head element has a structure in which a protective substrate is adhered thereon in order to prevent destruction of the thin film element portion.

A conventional magnetic head will be described below. FIG. 3 is an external view of a multi-channel thin film magnetic head having a conventional yoke type MR (magnetoresistive effect) reproducing element and an inductive recording element. 1 in FIG.
Reference numeral 1 is a ceramic substrate, and 12 is a thin film element portion formed by patterning and stacking thin films of various materials such as an MR element, a reproducing yoke magnetic material, a recording core magnetic material, a wiring material, and an insulating material. Thirteen
Is a protective layer made of alumina or the like, which is the uppermost layer of the thin film element portion, and 14 is a protective substrate made of ceramic, in which grooves 19 are machined. Reference numeral 15 is an adhesive, and 16 is a terminal portion.

[0004]

However, in the above-mentioned conventional structure, in order to significantly reduce the cost of the expensive thin film magnetic head, it is necessary to downsize the thin film element portion and increase the number of heads to be taken per substrate. Among them, there were some problems as shown below. First, when the size of the thin film element portion is reduced, the adhesion area becomes smaller accordingly, and the adhesion strength decreases. FIG. 4 shows the relationship between the bonding strength and the bonding area ratio in the conventional bonding method when the conventional head is downsized to 1/3. It can be seen from FIG. 4 that the strength and its variation are significantly deteriorated due to the decrease in the bonding area. Therefore, since the sufficient strength cannot be obtained, the yield in the processing step in the middle is bad, or the strength reliability test cannot be endured.

Further, it is necessary to make the thickness of the adhesive layer as thin as possible in terms of reliability when sliding the medium. FIG. 5 shows the relationship between the adhesive strength and the adhesive layer thickness. Although the strength increases as shown in FIG. 5 due to the increase in the thickness of the adhesive layer, uneven wear 1
7 or the elongation 18 of the adhesive may increase the spacing loss. In addition, since the groove width is limited as long as the groove 19 is machined, the width of the groove 19 becomes relatively large because the width of the protective substrate becomes small as the size becomes smaller.
The volume of the adhesive occupying the groove 19 becomes a large ratio in view of the total volume of the adhesive, and the width of the flat portion of the adhesive surface of the protective substrate 14 becomes small. As a result, the influence of swelling, characteristic deterioration due to stress, and instability of the adhesive layer thickness cannot be ignored.

Furthermore, simultaneous groove machining of a large number of heads is difficult by machining, and productivity is low. Therefore, the head having the conventional structure cannot be easily miniaturized, and only a reliable head can be produced, resulting in low productivity. The present invention is to solve these problems, even if the adhesive area of the thin film element portion and the protective substrate is reduced, it is possible to ensure the adhesive strength without thickening the adhesive layer of the medium sliding surface, Therefore, it is an object of the present invention to provide a thin film magnetic head which is inexpensive and has the same reliability as the conventional one due to miniaturization, and to provide a method of manufacturing a thin film magnetic head having high productivity.

[0007]

In order to achieve this object, a magnetic head according to the present invention has at least one of a thin film element portion side adhesive surface and a protective substrate side adhesive surface in the vicinity of a medium sliding surface and It is characterized in that it has fine grooves filled with an adhesive that are not exposed on the sliding surface of the medium.

The method of manufacturing the magnetic head of the present invention is
A step of polishing the thin film element portion side adhesive surface and the protective substrate side adhesive surface of the substrate on which the thin film element portion is created, and at least one of the thin film element portion side adhesive surface and the protective substrate side adhesive surface,
A step of forming a groove pattern that does not reach the medium sliding surface using a photoresist and creating a predetermined groove by processing the pattern by etching, and filling the groove with an adhesive, and then forming a thin film A thin film magnetic head manufacturing method comprising a step of abutting an element portion side adhesive surface and a protective substrate side adhesive surface with an adhesive to cure them.

[0009]

With this structure and the manufacturing method, a fine groove is formed at a required place, so that the thickness of the adhesive layer on the sliding surface is thin, the thickness of the adhesive layer on the groove portion is large, and the minute adhesive surface occupies the groove. By adopting a configuration in which the volume of the adhesive is a small proportion of the total volume of the adhesive, it is possible to realize a thin film magnetic head having high strength and excellent reliability.

Further, by forming a groove by using a pattern forming method using a photoresist and an etching technique, it is possible to realize a thin film magnetic head manufacturing method capable of fine groove processing and having high productivity.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of the thin film magnetic head of this embodiment. In FIG. 1, 1 is a ceramic substrate, and 2 is a thin film element portion formed by patterning and stacking thin films of various materials such as MR element, reproducing yoke magnetic material, recording core magnetic material, wiring material, and insulating material. 3 is a protective layer made of alumina or the like which is the uppermost layer of the thin film element portion 4, 4 is a protective substrate made of ceramics, and 5 is an adhesive. 6 is a terminal part. Reference numeral 7 is a groove patterned in the protective layer 3.

First, the structure of the head of the embodiment will be described. A thin film element portion 2 made of each thin film is arranged on a ceramic substrate 1, a groove 7 is provided in a protective layer 3 which is the uppermost layer of the thin film element portion 2, and the protective substrate 4 projects from the protective layer 3 via an adhesive 5. Aligned and glued. FIG. 2 shows each step of the method of manufacturing the magnetic head shown in FIG. In FIG. 2, reference numeral 8 is a photoresist, 9 is a thin film element portion side adhesive surface, 10 is a protective substrate side adhesive surface, and 20 is a medium sliding surface.

As shown in FIG. 2A, each thin film material is patterned and stacked on the ceramic substrate 1 to form a large number of thin film element portions 2, and the thin film element portion side adhesive surface 9 is polished flat. Next, as shown in FIG. 2B, a pattern of the groove 7 which does not reach the medium sliding surface 20 is formed on the flattened thin film element side adhesive surface 9 by using a photoresist 8.
As shown in FIG. 2C, a predetermined groove 7 is created by processing the thin film element side adhesive surface 9 by etching. Next, as shown in FIG. 2D, the photoresist 8 is removed with a solvent. Next, as shown in FIG. 2E, the protective substrate side adhesive surface 10 is polished, and the adhesive 5 is applied to at least one of the thin film element portion side adhesive surface 9 and the protective substrate side adhesive surface 10 and abutted. To glue. Next, one thin film element portion 2 is cut into a predetermined size (not shown) to obtain the thin film magnetic head shown in FIG. Although this step is performed in a substrate state in which a large number of thin film elements 2 are arranged, it is also possible to cut out into a rod state in which a plurality of heads are arranged in a row during the step and then proceed with the same step.

In this embodiment, the groove 7 is formed on the adhesive surface 9 on the thin film element side, but the groove 7 may be formed on the adhesive surface 10 on the protective substrate side, or the adhesive surface 9 on the thin film element side, the protective substrate. It goes without saying that the groove 7 may be formed on both of the side adhesive surfaces 10. In this embodiment, the groove 7 has a depth of about 4 μm and a width of 50 μm.
Then, the grooves were formed on the protective film side by chemical etching by chemical etching using alumina as the protective film, but the method is not limited.

Further, in this embodiment, by forming the grooves 7 in a lattice pattern, the thickness of the adhesive layer was stabilized over the entire adhesive surface, and uniform adhesive strength was obtained. Further, in this embodiment, the groove 7 is formed in the protective layer 3 by defining the positional relationship with the thin film element portion 2 to form a pattern, so that the groove 7 is used as a reference for alignment by cutting out into a rod state during the process. Also, by forming a pattern for removing the groove 7 and the protective layer 3 on the terminal portion 6 with the same mask, the protective layer 3 on the terminal portion 6 can be formed when the groove 7 is formed by etching. There is also an advantage that can be removed at the same time.

A comparison between the miniaturized thin film magnetic head according to the present embodiment, the thin film magnetic head miniaturized by the conventional manufacturing method, and the conventional thin film magnetic head will be compared.

[0017]

[Table 1]

As shown in FIG. As is clear from this (Table 1), the thin-film magnetic head according to the present embodiment has sufficient strength to withstand processing and ensure reliability even if the thin-film magnetic head is downsized and the adhesion area is reduced. There is. Moreover, since the thickness of the adhesive at the portion exposed to the medium sliding surface is not changed, the strength of the magnetic head is increased without increasing spacing loss due to uneven wear or elongation of the adhesive. Further, the volume of the adhesive is small, and the adverse effects due to the swelling of the adhesive and the adverse effects due to the groove extension of the adhesive at the time of processing the sliding surface are smaller than those of the conventional magnetic head having grooves formed by machining.

[0019]

As described above, according to the present invention, in a magnetic head constructed by forming a thin film element portion on a substrate and then adhering a protective substrate to the thin film element portion, a thin film element portion side adhesive surface or By disposing a fine groove filled with an adhesive that is not exposed to the medium sliding surface in the vicinity of the medium sliding surface on at least one of the protective substrate side adhesive surfaces, the thin film element portion It is intended to realize an excellent magnetic head with high strength, high yield, and high reliability when downsizing.

Further, the manufacturing method of the present invention comprises a step of polishing the thin film element portion side adhesive surface and the protective substrate side adhesive surface, and a photoresist on at least one of the thin film element portion side adhesive surface and the protective substrate side adhesive surface. Step of forming a groove pattern by using it, step of creating a predetermined groove by etching the surface on which the pattern was created, and bonding the thin film element side adhesive surface and protective substrate side adhesive with the groove filled. By including the step of bringing the surfaces into contact with each other via an adhesive and hardening the same, a large number of necessary fine grooves that cannot be machined can be simultaneously formed. As a result, the number of thin film element portions taken from one substrate can be significantly increased, and the thin film element portions can be provided at low cost.

[Brief description of drawings]

FIG. 1 is an external view of a magnetic head according to an embodiment of the invention.

FIG. 2 is an explanatory diagram of each step of the magnetic head manufacturing method according to the embodiment of the present invention.

FIG. 3 is an external view of a conventional magnetic head

FIG. 4 is a diagram showing actually measured values of the relationship between the adhesive strength and the adhesive area of a conventional head.

FIG. 5 is a diagram showing measured values of the relationship between the adhesive strength of the conventional head and the adhesive layer thickness.

FIG. 6 is an explanatory view of a problem when the adhesive layer in the conventional head is thick.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic substrate 2 Thin film element part 3 Protective layer 4 Protective substrate 5 Adhesive 6 Terminal part 7 Groove 8 Photoresist 9 Thin film element side adhesive surface 10 Protective substrate side adhesive surface 20 Medium sliding surface

Claims (2)

[Claims] 1. A magnetic head constructed by forming a thin film element portion on a substrate and then adhering a protective substrate to the thin film element portion, wherein the thin film element portion side adhesive surface or the protective substrate side adhesive surface is formed. A thin-film magnetic head, characterized in that at least one of them has a fine groove filled with an adhesive near the medium sliding surface and not exposed to the medium sliding surface. 2. A step of polishing the thin film element portion side adhesive surface and the protective substrate side adhesive surface of the substrate on which the thin film element portion is formed, and at least one of the thin film element portion side adhesive surface and the protective substrate side adhesive surface. On the other hand, a step of forming a groove pattern that does not reach the medium sliding surface using a photoresist, and processing the thin film element side adhesive surface or the protective substrate side adhesive surface on which the pattern is formed by etching. And a step of forming a predetermined groove with the adhesive, and a step of abutting and curing the thin film element side adhesive surface and the protective substrate side adhesive surface via an adhesive while the groove is filled with an adhesive. And a method of manufacturing a thin film magnetic head.