JPH0241804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a thin-film magnetic head, and is a method for manufacturing a protective substrate of the head by bonding it to glass.

[Background technology]

Conventionally, magnetic heads for audio equipment that record audio magnetically have a range from maximum output level to playback noise level determined by flutter, which is the temporal fluctuation of the magnetic recording medium when the tape runs. Therefore, it is said that analog recording methods are disadvantageous. Recently, it has become common for magnetic heads of this type to employ PCM recording, which allows digital recording by quantizing and sampling signals using a step-like transfer function. Therefore, the schematic structure of a magnetic head for PCM audio is shown in Figure 1.A so-called thin film is formed by forming a coil pattern path 2 and a ferromagnetic film 3 on a substrate 1 made of ferrite or sapphire through an insulating film 4. A separate protective substrate 5 is placed close to these structures to provide a gap, and a low melting point glass 6 is melted and infiltrated into the gap to form an adhesive. However, in order to bond the thin film magnetic head with low melting point glass 6, as shown in FIG. Because the work method used was to heat and melt the glass while holding the glass body 8 between them, and pour it into the gap 9 between them, it was difficult to pour the molten glass into the gap 9 with a uniform thickness, and in the end, the entire surface was melted. It has been impossible to fix the thin film head with uniform adhesive strength and, as a result, to prevent chipping during polishing of the thin film head.
Therefore, this thin film magnetic head has a limited mechanical strength, and there is a need for improvement. Moreover, PCM
Since it is a recording magnetic head, it is inevitable to take advantage of its characteristics to promote multi-tracking, and from this point of view as well, the magnetic head becomes slightly larger, so even more uniform and sufficient adhesive strength is required. .

[Disclosure of the invention]

This invention was proposed to solve the above problem, and relates to a device in which a magnetic head is formed by laminating a thin film head pattern and a protective substrate.
A glass lining layer is pre-formed on at least one side of the protective substrate, and the protective substrate and thin film head pattern are held and heated using a clamping jig made of a material that has a different thermal expansion coefficient from that of the protective substrate to melt the glass lining layer. It is characterized in that it is laminated and integrally formed by cooling it after being deposited. Therefore, this invention
Not only can the thin-film-prepared structure and the protective substrate be bonded with sufficient strength and uniformity, but the thickness of the bonded glass can be controlled to the desired thickness, and the spacing between the substrates can also be set accurately. There are great advantages that can be achieved.

[Best mode for carrying out the invention]

The specific best mode of this invention will become clear from the following examples.

First, FIGS. 3 and 4 are cross-sectional views of a thin film-formed structure and a protective substrate of a thin film magnetic head prepared for manufacturing a recording thin film magnetic head for PCM audio according to an embodiment of the present invention. Reference numeral 10 in FIG. 3 is a sapphire substrate, on the surface of which a lead pattern 11 for reproduction signals from a magnetic material such as permalloy and an insulating layer 12 are formed as thin films by photolithography technology similar to that used for semiconductor devices. . Reference numeral 14 in FIG. 4 is a sapphire substrate or a crystallized glass substrate similar to 10, and a low melting point glass layer 15 serving as an adhesive is formed on the surface. In order to form the low melting point glass layer 15 here, the following steps are performed. First, in order to coat a sapphire substrate with a thermal expansion coefficient (hereinafter referred to as α) of 55×10 ^-7 /°C or a more suitable crystallized glass substrate 14, a low softening point of 350°C is applied at α100×10 ^-7 /°C. A glass paste suitable for printing is prepared by adding nitrified cotton and butyl acetate to melting point glass powder. Next, the glass paste is printed to a thickness of 25 μm using a screen printing method, and baked at about 400° C. while blowing with air to form a glass lining, forming a low melting point glass layer 15 of about 15 μm.

Now, in order to integrate a thin film magnetic head by using the thin film formed structure and the protective substrate as shown in FIGS. 3 and 4, FIG. 5 shows a plan view, and FIG. 6 shows a longitudinal sectional view. Use a clamping jig as shown. In other words, in Figures 5 and 6, 16 and 17 have α of 40×
A convex block and a square block made of 10 ^-7 graphite are used for tightening screws (α180×10 ^-7 /
℃) 18, 18, their clamping gap g
and g' can be expanded and contracted. Using this clamping jig, when the thin film-formed structure and the protective substrate are clamped together and placed in a neutral atmosphere furnace at approximately 470°C, the glass-lined low-melting glass layer 15
The substrates 10 and 14 and the convex and square blocks 1
Thermal expansion difference g of 6 and 17 x (55-40) x 10 ^-7 x 470
=7.05× ^10-4 ×g and thermal expansion difference g′×(180−40)× ^10-7 ×470=6.58× between square block and tightening screw
It is compressed by a pressure equal to the sum of 10 ^-3 × g', and is evenly sandwiched and fused over the entire surface. Thereafter, it is cooled and taken out from the clamping jig to obtain the desired thin film magnetic head. The final thickness of the glass lining layer can be determined freely by designing g and g'.

From the above explanation, in the method for manufacturing a thin film magnetic head of the present invention, the glass lining layer is fused while being heated by the expansion pressure corresponding to the thermal expansion difference between the clamping jig and the protective substrate, so it is not limited to simply uniform clamping over the entire surface. figure,
The glass lining layer can be hardened more firmly, and the thickness can be set to the designed value.

In addition, in this invention, the materials of the ferromagnetic thin film, the protective substrate, and the clamping jig may be made of sendust alloy, ferrite, carbon, etc., in addition to the above-mentioned embodiments, and similar effects can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional thin film magnetic head, Figure 2 is a cross-sectional view of a conventional thin film magnetic head.
The figure is a cross-sectional view during glass fusion, Figures 3 and 4.
The figure is a sectional view of a structure with a thin film formed thereon and a protective substrate used in an embodiment of the present invention, and FIGS. 5 and 6 are a plan view and a longitudinal sectional view of a clamping jig for clamping them. . 10, 14... Protective substrate, 11... Thin film head pattern, 15... Glass lining layer, 16,
17... Concave and convex block of clamping jig.

Claims (1)

[Claims] 1. Regarding magnetic heads formed by laminating a thin film head pattern and a protective substrate, a glass lining layer is formed in advance on at least one side of the protective substrate, and a clamp made of a material with a different coefficient of thermal expansion from that of the protective substrate is attached. A method for manufacturing a thin film magnetic head, characterized in that a protective substrate and a thin film head pattern are held in a jig and heated, and a glass lining layer is fused and then cooled to form an integrated laminated structure.