JPS6028016A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obviate generation of foam in an adhesive material which adheres a protective material stuck onto an element part and signal electrodes by forming a groove on the adhered surface of the protective plate. CONSTITUTION:A cleaned glass base plate 1 is prepd. and a ''Permalloy'' film which is a magnetic film as an MR element and an aluminum film to be used as an electrode for introducing signal is formed by a method for depositing thin film such as vapor deposition or sputtering on one side surface thereof. The aluminum film is then formed as signal-introducing electrodes by a photoetching method and the unnecessary part of the ''Permalloy'' film is also removed by a photoetching method to form and MR element part. The electrodes 5 and the MR element part are coated with a silicon dioxide SiO2 film thereon to improve the resistance to environment. On the other hand, a protective plate 2 is formed by cutting a glass material to a prescribed size and working it to provide a longitudinal groove 3 on the side surface thereof. The groove 3 side of said plate is stuck to the plate 1 by means of an adhesive agent.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a thin film magnetic head, and more particularly to a thin film magnetic head having a structure in which a magnetic film or a conductive film is formed on a substrate, and a protective plate is bonded to a magnetic circuit pattern. It is.

Conventional technology Thin film magnetic heads generally consist of a magnetic film such as sendust or permalloy, AU, CU, etc. on a substrate such as ferrite.
, A conductive film such as AL is formed by a thin film deposition method such as sputtering or vapor deposition, and these thin films are subjected to a photo-etching process to form a magnetic circuit and an electric circuit in a predetermined pattern.

Then, in order to protect these circuit patterns and form a magnetic recording medium sliding surface, they are bonded together using an adhesive on the patterns, and the magnetic recording medium sliding surface side is ground to obtain a completed thin film magnetic head. There is.

During the process of manufacturing such thin-film magnetic heads, when attaching the protective plate to the pattern on the substrate, as mentioned above, the protective plates are stacked with the adhesive in between, and the adhesive is cured while applying sufficient pressure. It is carried out.

By the way, if a structure is adopted in which the protective plate is bonded using an adhesive, air bubbles will be generated in the adhesive after the adhesive is cured.

The causes of air bubbles are that the solvent in the adhesive evaporates due to heating, which becomes air bubbles, and that the air bubbles trapped during the bonding of the protective plates are pressurized. The problem is that they cannot escape and remain in the adhesive.

When such bubbles are generated, the following various problems occur.

(11) If bubbles occur near the element part formed from the magnetic film of the thin-film magnetic head, especially near the sliding surface of the magnetic recording medium,
When grinding the sliding surface side of a magnetic recording medium to form a cylindrical surface, grinding occurs on the adhesive layer, causing spacing loss, and cracks and chipping of the adhesive layer. (2) If air bubbles are generated at the interface between the substrate or protective plate of the thin film magnetic head and the adhesive layer, the adhesive area will be reduced, the adhesive strength will be reduced, and the protective plate will peel off.

(3) The gas in the sealed bubbles expands or contracts due to temperature changes, reducing the reliability of the magnetic head.

(4) If air bubbles exist on the sliding surface side of the magnetic recording medium, magnetic powder on the magnetic recording medium side will accumulate in the traces of the air bubbles.

(5) Water enters behind the bubbles existing on the sliding surface side of the magnetic recording medium, making it easy for elements made of magnetic films to corrode.

Purpose The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and is to prevent the generation of air bubbles in the adhesive that adheres the protective plate located on the sliding surface side of the magnetic recording medium of the thin-film magnetic head. The object of the present invention is to provide a magnetic head configured as described above.

EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

First Example In the following examples, an MR magnetic head using a magnetoresistive element (hereinafter abbreviated as MR element) is shown as an example, and glass is used as the substrate and protection plate of the head, and as an adhesive material. shows an example using water glass (sodium silicate aqueous solution).

To manufacture an MR head using such a material, first, as shown in FIG. 1, in step S1, a cleaned glass substrate as shown by reference numeral 1 in FIG. 3 is prepared.
A permalloy film as a magnetic film as an MR element and an aluminum film as an electrode for signal introduction are formed on the side surface by a thin film deposition method such as vapor deposition or sputtering (step 82).

These permalloy films and aluminum films are formed in a continuous state.

Next, in step S3, an aluminum film is formed as a signal introduction electrode by photoetching, and in step S4, unnecessary portions of the permalloy film are removed by photoetching to form an MR element section.

Subsequently, in step S5, a silicon dioxide (S'02) film is formed to cover the signal electrode and MR element portion in order to improve environmental resistance.

On the other hand, for the protection plate, a glass material is prepared in step ↑1 of Fig. 1, cut to a predetermined size in step T2, and grooves are formed along the longitudinal direction on the side surface of the glass plate, which is the protection plate, in step T3. Process.

Thereafter, cleaning is performed in step T4, and this is bonded to the substrate side in step S6 in a positional relationship as will be described later, pressurized in step S7, and heated and cured in step 8B to obtain a thin film magnetic head.

As shown in FIG. 2, the protection plate 2 of the MR head manufactured through the above-described steps has grooves 3 formed in one side thereof in a continuous manner in the longitudinal direction.

On the other hand, an MR element 4 and an electrode 5 are formed on the substrate 1 by a photoetching process.

This state is shown in FIGS. 3 and 4.

By the way, in order to stack the protection plate 2 on the substrate 1, the groove 3 side is placed on the substrate 1 side, but the groove 3 is positioned closer to the magnetic recording medium sliding surface than the MR element 4, as shown in FIG. A position close to the MR element 4 is selected, or a position closer to the electrode 5 than the MR element 4 as shown in FIG.

If the groove 3 is located on the MR element 4, when the sliding surface side of the recording medium is ground, the groove 3 becomes a gap and causes a grinding error, which is inappropriate.

After the protective plate 2 is stacked on the substrate 1 in this way, as shown in FIG. 5, heat is applied while applying pressure in the direction in which the substrate 1 and the protective plate 2 overlap to harden the water glass that is the adhesive.

Then, most of the air bubbles generated in the adhesive material are collected in the groove 3, and when heating is performed while applying pressure to the substrate 1 and the protection plate 2, air bubbles are generated near the MR element 4 during heating. Air bubbles tend to collect in the groove 3.

After fixing the protection plate 2 in this manner, if a cut is made on a straight line passing through the MR element 4 in the longitudinal direction, the magnetic recording medium sliding surface side, which is the side facing the MR element 4, will be cut. There will be no bubbles.

Since the present embodiment is constructed as described above, no air bubbles are generated in the periphery of the MR element, the adhesive layer is thinned, and no grinding bumps are generated when the sliding surface side of the magnetic recording medium is ground.

Second Embodiment FIG. 6 is for explaining another embodiment of the present invention. In this embodiment, the MR element is held between two
Strip grooves 3, 3 are formed.

Ml like this? When the two grooves 3, 3 are arranged to sandwich the element 4, the air bubbles are guided toward the two grooves, so that the air bubbles can be collected more efficiently.

By the way, as a result of experiments, it was found that the appropriate number of grooves 3 is 2 to 4, and that when the number is 5 or more, the bonding area decreases and the bonding strength decreases.

In FIG. 6, the straight line indicated by the symbol a-a indicates a cutting line when grinding the sliding surface side of the magnetic recording medium, and the grooves located on the outside of the MR element 4 are cut off during grinding.

Although the above-mentioned embodiment has been explained using an MR head as an example, it is of course applicable to an inductive head as well.

Effects As is clear from the above explanation, according to the present invention, a structure is adopted in which a groove is formed in the protection plate which is superimposed and bonded on the substrate, and the groove is located near the element of the thin-film magnetic head. Many of the air bubbles generated in the magnetic recording medium can be collected in the grooves, and there are almost no air bubbles near the sliding surface of the magnetic recording medium of the thin-film magnetic head. never occurs.

[Brief explanation of drawings]

Figures 1 to 5 illustrate an embodiment of the present invention.
FIG. 1 is a flowchart explaining the manufacturing process, FIG. 2 is a perspective view of the protection plate, and FIGS. 3 and 4 are explanatory diagrams showing the positional relationship between the grooves formed in the protection plate and the element. FIG. 5 is an explanatory diagram showing a pressurized state, and FIG. 6 is an explanatory diagram showing another embodiment of the present invention. 1... Substrate 2... Protective plate 3... Groove 4... MR element 5... Electrode patent applicant Canon Electronics Co., Ltd. 1WA Figure 2 Figure 3 Figure 4 Figure 5, Figure Figure 6

Claims (5)

[Claims] (1) In a thin film magnetic head in which an element part and a signal electrode made of a magnetic film are formed as thin films on a substrate, and a protective plate is attached to the element part and the signal electrode, a groove is formed on the adhesive surface of the protective plate. A thin film magnetic head characterized by forming. (2) Claim 1, characterized in that the groove is provided so as to be substantially parallel to the element and located near the element.
The thin film magnetic head described in Section 1. (3) A thin film magnetic head according to claim 1 or 2, characterized in that there is a plurality of grooves. (4) A thin film magnetic head according to claim 3, wherein the plurality of grooves are arranged to sandwich the element. (5) The thin film magnetic head according to any one of claims 1 to 4, wherein the element is a magnetoresistive element.