JPS59140618A - Production of thin film magnetic head - Google Patents

Abstract

PURPOSE:To permit secure adhesion and to enable easy control of the thickness of adhesive glass by forming a glass lining layer on a protective base plate, sandwiching the protective base plate and thin film head pattern by means of sandwiching jigs having the coefft. of thermal expansion different from said coefft. of the protective base plate, heating the base plate and pattern and welding the glass lining layer. CONSTITUTION:A low melting glass layer 15 is formed on the surface of a sapphire base plate 14 (coefft. of thermal expansion alpha=55X10<-7>/ deg.C) which is a protective base plate (figure A). Sandwiching jigs C, D are used to laminate and unit the thin film magnetic head. 16, 17 denote projecting and square-shaped blocks of graphite having 40X10<-7>alpha and the sandwiching gaps (g) and g' thereof are adjustable to expand or contract by lock screws (alphaapprox.=180X10<-7>/ deg.C) 18, 18. When a structural body formed already with the thin film thereon (figure B) and the protective base plate are sandwiched by such jigs and are put in this state into a neutral atmosphere furnace kept at about 470 deg.C, the layer 15 subjected to glass lining is compressed under the pressure by as much as the sum of the difference in the thermal expansion between the plates 10, 14 and the blocks 16, 17 and the difference in the thermal expansion between the block 17 and the screws 18, by which said plate and base plate are uniformly sandwiched and welded over the entire surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing a thin-film magnetic head, and is a method of manufacturing a protective substrate of the head in which all of the protective substrates are bonded to glass.

[Background technology]

Traditionally, magnetic heads for audio equipment that record audio magnetically have a magnetic recording medium, the tape, whose range from maximum output level to playback noise is determined by flutter, which is a temporal fluctuation when the tape is running. , which is said to be disadvantageous with analog recording methods. So recently,
This kind of magnetic head generally employs PCM notation fAk, which can perform full quantization of signals using a stepped transfer function, perform full sampling, and perform digital recording. Therefore, the schematic structure of a POM audio magnetic head is as shown in Fig. 1.A coil pattern path 2 and a ferromagnetic film 3 are formed on a substrate 1 made of ferrite, sapphire, etc.
A so-called thin film is formed through all of the insulating films 4, and a separate protective substrate is placed 5'ft close to these structures to fill the entire gap, and the low melting point glass 6 is melted and infiltrated into the gap to bond it. It was formed. However, in order to bond and form this thin film magnetic head with low melting point glass 6, as shown in FIG. 8 Because all the work methods used were to heat and melt the molten glass while it was completely sandwiched and pour it into the gap 9 between the two, it was difficult to pour the molten glass into the entire gap 9 with a uniform thickness, and in the end, the entire surface was melted. It has been impossible to bond with uniform adhesive strength and, as a result, to completely prevent chipping during polishing of the thin film head.

Therefore, this thin film magnetic head has a limit in mechanical strength, and it is necessary to improve it. However, since it is a POM recording magnetic head, it is inevitable that all its features should be considered to make it fully multi-track.From this point of view, the magnetic head will also become a little larger, so it must be made even more uniform and have sufficient contact layer strength. was required.

[Disclosure of the invention]

This invention has been proposed to solve all of the above problems, and for a device in which a thin film head pattern and a protective substrate are fully laminated to form a magnetic head, a glass lining layer is completely formed on at least one of the protective substrates in advance. Then, use a clamping jig made of a material with a coefficient of thermal expansion different from that of the protective substrate to sandwich and heat the RAD pattern on the protective substrate and thin film, and after the glass lining layer has completely fused, cool it to form an integrated laminated layer. It is characterized by Therefore, in this invention, not only can the thin film-formed structure and the protective substrate be brought into uniform contact with each other with sufficient strength, but also the total thickness of the contact glass can be controlled to a desired thickness. Therefore, there is an excellent advantage that the distance between the substrates can be set accurately.

[Best mode for carrying out the entire invention]

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

First of all, FIGS. 3 and 4 show P which is an embodiment of this invention.
FIG. 2 is a cross-sectional view 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 OM audio. In FIG. 3, 1O is a 7F ear board with lead patterns 11. on its surface for reproduction signals from a magnetic material such as permalloy. The insulating layer 12 is formed into a thin film using a photolithography technique similar to that used for semiconductor devices.

14 in FIG. 4 is a sapphire substrate or a crystallized glass substrate similar to lo, and a low melting point glass layer 15 serving as a sacrificial material is formed on the surface. In order to completely form the low melting point glass layer 15, the following steps are performed.

First, a sapphire substrate or a more suitable crystallized glass substrate 14 with a thermal expansion coefficient (hereinafter referred to as α) of 55XIO/''C is used.
The softening point is 3 at α lOO x 107°C for coating on surfaces such as
Nitrified cotton and butyl acetate were added to low melting point glass powder ice at 50°C to prepare a glass paste suitable for printing. Next, that glass space)? Printed to a thickness of 25 μm using the screen printing method and printed approximately 40 μm while air blowing.
0” Baking at C and complete glass lining 157
A low melting point glass layer 15 having a hardness of Am is entirely formed.

Now, in order to integrate all the layers of the thin film magnetic head 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. Use all types of clamping jigs. That is, in Figures 5 and 6 In, 1
6.17Fiα is a convex block and a square block made of 40XIO-' graphite, and the tightening screw (α
χ180×107°C)' 18.18, the gap with the clamp and the full extension and contraction of 9' can be adjusted. Using this clamping jig, when the thin film-formed structure and the protective substrate are fully clamped and placed in a neutral atmosphere furnace at approximately 470″C, the glass-lined low-melting glass layer 15 will be Substrate 10.1
4 and the thermal expansion difference X between convex and square blocks 16.17
(55-40)XIOX470=7.05X1o x9
and the difference in thermal expansion between the square block and the tightening screw RI'X(1
80-40)XIOX470=6.58X10”-3×
The edge is compressed by pressure equal to the sum of Q' and clamped uniformly over the entire surface:
wear. 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 depending on the design of 2°9'.

From the above explanation, in the method for manufacturing a thin film magnetic head of the present invention, since the glass lining layer is fused while being heated with the expansion force equal to the thermal expansion difference between the jig and the protective substrate, it is possible to simply flatten the entire glass lining layer uniformly. Not only is it easy to attach, but it can also be hardened more firmly than glass lining MR, and the wall 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 are all made of materials other than the above-mentioned embodiments, such as Sendust alloy,
Ferrite, carbon, etc. may also be used and have similar effects.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional thin film magnetic head, FIG. 2 is a sectional view of its glass fusion layer, and FIGS. 3 and 4 are a thin film formed structure and protection used in an embodiment of the present invention. The cross-sectional view of the substrate, FIGS. 5 and 6, are a plan view and a vertical cross-sectional view of the clamping jim that clamps the substrate. 10.14...Protective substrate, 11...Thin film head pattern, 15...
Glass lining layer 1 16.17... Concave and convex block of clamping jig. 4 Figure 4

Claims (1)

[Claims] For those in which the entire magnetic head is formed by laminating the thin film head pattern and the protective substrate, a glass lining layer must be completely formed on at least one side of the protective substrate in advance, and a clamping treatment made of a material with a coefficient of thermal expansion different from that of the protective substrate may be used. 1. A method of manufacturing a thin film magnetic head, which comprises the steps of sandwiching and heating a holding substrate and a thin film head pattern between tools, and cooling the glass lining layer after completely melting it to form an integrated layered structure.