JPS6358612A - Production of thin film magnetic head - Google Patents

Abstract

PURPOSE:To produce a stable lower core by forming the grooves and a magnetic film on a substrate and grinding the surface of the substrate after applying a heat treatment to the substrate in a magnetic field. CONSTITUTION:A magnetic film 2 is formed on a substrate 1 containing the lower core grooves 3 and this substrate 1 undergoes a heat treatment in a magnetic field to reduce the warp of the substrate 1 caused when a core member is formed. Then the substrate 1 is mounted to a jig and lapped. It is desirable to apply the load to the substrate 1 in the heat treatment in order to obtain a stable lower core.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of manufacturing a thin film magnetic head.

In particular, the present invention relates to a method of manufacturing the head with high productivity.

[Conventional technology]

A conventionally known thin-film magnetic head is the JP-A-6
As described in No. 0-22<5008, the structure is such that the lower core is embedded in a groove formed in the substrate. A method of forming the lower core of a conventional head will be explained with reference to FIG. This figure is a process diagram for forming the lower core of a conventional head, in which 1 is a substrate and 2 is a magnetic film.

3 is a groove formed in the substrate.

A groove of a desired shape is formed on the surface of the substrate 1 using a high-precision diver. (FIG. 4α) After that, a magnetic film serving as a core material is formed, and (FIG. 4b) the portion of the magnetic film other than the two groove portions is removed by grinding. (Fig. 4 C) [Problems to be Solved by the Invention] However, in the conventional thin film head manufacturing method, the warpage of the substrate (Fig. 5 h) observed after forming the core material is not taken into account. There were problems as shown.

That is, if surface grinding is performed with the substrate in a warped state, a problem arises in that the thickness of the lower core after lapping varies depending on the location. For example, if we take the case shown in Figure 6,
The thickness of the lower core at the center of the board is thinner than the thickness at the edges. Therefore, in order to obtain a uniform bottom core thickness across the substrate, it is necessary to flatten the substrate before lamps.

Conventionally, as the method for flattening the substrate, a method has been used in which a load is applied to a jig or the like to attach the substrate. However, with this method, 1) sufficient substrate flatness cannot be obtained; 2) There were problems such as the substrate being damaged when a load was applied.

The purpose of the present invention is to solve the problems of the above-mentioned prior art,
The object of the present invention is to provide a stable lower core forming method.

[Means for solving problems]

The above object can be achieved by performing heat treatment 1, for example, load impression heat treatment, after forming the core material.

[Function] By performing the heat treatment, the warpage of the substrate after the heat treatment can be reduced.

〔Example〕

Generally, substrate warpage after film formation is closely related to residual stress in the film. Residual stress is broadly classified into thermal stress and intrinsic stress, the former being due to the difference in thermal expansion coefficient between the film material and the substrate, and the latter being due to the film growth process specific to the thin film.

The inventor's systematic study on internal stress revealed that thermal stress is dominant in Permalloy and Sendust films.
It has become clear that in the case of an amorphous magnetic alloy film such as a CoNbZr film, intrinsic stress is dominant.

Furthermore, although it is generally difficult to alleviate thermal stress, it is known that inherent stress can be reduced by heat treatment or the like. Particularly in the case of a CoNbZr film, the inventors have found that the amount of warpage of the substrate changes as shown in FIGS. 2 and 6. Figure 2 Film thickness and As dgpo
, FIG. 3 shows the change in the amount of substrate warpage due to heat treatment.

In addition, in FIG. 5, the amount of warpage after heat treatment is As -cL
It is standardized by gpo, the amount of warpage over time. As shown in the figure, the amount of warpage of the substrate increases as the film thickness increases, and decreases as the heat treatment temperature increases.

In particular, regarding the heat treatment temperature dependence, when heat treatment is performed while applying a load to forcibly correct the warpage of the substrate, the amount of warpage after heat treatment is smaller than when no load is applied.

The flatness (amount of warpage) of the substrate required in the lamp process is 5μ
m or less, and the heat treatment temperature to achieve this is 1. For example, when the film thickness is 60 μm, from Figures 2 and 3, the heat treatment temperature is 400 μm.
The temperature is 550'C or higher (with load) or 550'C or higher (with load).

However, when a thin amorphous alloy thin film such as a CtrNbZr film is heat-treated in a field, the magnetic domain walls become stuck and the magnetic properties are significantly impaired. In order to avoid this, it is necessary to perform heat treatment in a state where there are no domain walls, and for this purpose it is necessary to apply a magnetic field during heat treatment.

Hereinafter, specific embodiments of the invention will be described.

(Example 1) Regarding the lower core forming step according to the present invention.

This will be explained using FIG. FIG. 1 is a diagram showing the lower core forming process. In the figure, 1 is a substrate made of a sintered body of M n O and N i O, 2 is a CoN1rZr film as a core material, and 3 is a core material.

This is a groove for the lower core made on the board.

Note that the substrate groove forming process, core material forming process, and lamp process are almost the same as in the conventional example. Also, the shape of groove 3 has a depth of 30 mm.
μ7B, φ: 60 μm, and the thickness of the CoNbZr film 2 is 30 μm. After forming the core material 2, the amount of substrate warpage was approximately 30 μm, and by performing heat treatment in a 5O= magnetic field at 2400° C. or higher, the amount of substrate warp was reduced to 5 μm or less. As a result of mounting this substrate on a jig and lapping, the variation in the thickness of the lower core film was less than ±2 μm, and there was no damage to the substrate during lapping.

[Example 2] While applying a load (0.2 kp/i or more), 35
The same results as in Example 1 were obtained when heat treatment was performed for 60 minutes at a temperature of 0'0 or more.

In addition, in the conventional lapping process, there was sometimes a problem that the film peeled off, but in this example, there was no film peeling at all. Therefore, as a ripple effect of the present invention, an increase in the adhesion strength between the substrate and the CoNbZr film was observed.

〔Effect of the invention〕

According to the present invention, it has become possible to provide a stable lower core forming method.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the process of forming the lower core of the thin film magnetic head of the present invention, FIG. 2 is a diagram showing the relationship between the film thickness and the amount of warpage, and FIG. 3 is a diagram showing the relationship between the heat treatment temperature and the amount of warpage. FIG. 4 is a process diagram for forming the lower core of a conventional thin-film borium head. １・・・・・・・・・・・・Substrate 2・・・・・・・・・Abrasive film 6・・・・・・・・・・・・Lower core groove agent Patent attorney Shi Ogawa Katsu Isamu, 1 degree gap 1 ko (violent gourd 21 Mejiro-, Toyo = 111 Hi 3 Senjitsu 7 Condolences Takashima 2 Zukoshi Yu (F-) Hot Ri 1 cliff (・0) A 4 Mouth

Claims (1)

[Claims] 1. In a method for manufacturing a thin film magnetic head having a lower core embedded in a substrate or an insulating layer formed on a substrate, the lower core forming step is performed at least in a magnetic film forming step and in a magnetic field. A method for manufacturing a thin film magnetic head, comprising a heat treatment process and a surface grinding process. 2. The magnetic field heat treatment step according to claim 1,
A method for manufacturing a thin film magnetic head, characterized in that the process includes performing heat treatment in a magnetic field while applying a load to a substrate. 3. A method for manufacturing a thin film magnetic head, characterized in that the magnetic film forming step according to claim 1 is a step in which intrinsic stress is dominant as the internal stress of the formed magnetic film.