JPS5972636A - Manufacture for thin film head - Google Patents

Abstract

PURPOSE:To obtain a head possible for high speed switching, by increasing the width of a magnetic film part manufactured at the same time as a magnetic core and eliminated at the completion of magnetic head to decrease a diamagnetic field, in manufacturing the magnetic core by the electric plating. CONSTITUTION:In manufacturing a thin film magnetic head for an electronic computer by means of the frame plating method, a part 6 of a nonmagnetic plating frame 1 prolonged in the direction of application of a magnetic field B (shown by the arrow) at the magnetic film manufacture at a straight line segment A-A' eliminated at the completion of magnetic head is increased more than the width of a gap 4, i.e., track width, and the plating of the magnetic substance is applied together with that for the magnetic core 3. Thus, the diamagnetic field produced in the arrow C is reduced because of the presence of the frame 1 and a strong magnetism anisotropy is provided to the core 3. Then, the strong magnetism anisotropy is given to the core 3 by the application of the weak magnetic field 3 and a head possible for fast magnetization switching is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a thin film head used in a magnetic recording device.

It is preferable that the change in magnetization of a magnetic head, particularly a magnetic head used in a magnetic disk device for an electronic computer, is caused by magnetization rotation with fast switching. In an electromagnetic induction type thin film head, when the magnetic flux from the recording medium and the axis of easy magnetization of the magnetic core are parallel, domain wall movement occurs, and when they are perpendicular, magnetization rotation occurs. Therefore, when manufacturing a thin film head, the film is manufactured in a magnetic field, and then the magnetic core is given magnetic anisotropy by means such as heat treatment in the magnetic field.
A method is being used to create a head in which domain wall movement is less likely to occur.

When making a magnetic core by electroplating, a frame plating method as shown in FIG. 1 has conventionally been used. 7. After forming the plating frame 1 with an electrical insulator such as photoresist, plating a magnetic material such as Ni-Fe on the parts other than the plating frame 1, and then removing the part indicated by number 2 in the figure by etching. , make part 3 of the magnetic core. Furthermore, after forming the gap layer, insulating layer, coil, etc., the remaining 9 parts of the magnetic core are formed as part 3 of the magnetic core made earlier.
make in the same way. The element manufactured in the above manner is cut and polished down to plane A-A/.

The plane AA' becomes the floating plane of the magnetic herad slider, and signals are exchanged with the recording medium near the gear part 4 of the magnetic core.

A portion 5 extending downward from the gap portion is used to connect the two layers of magnetic cores produced by the method described above and to perform an inductance test in a wafer state (before processing with a magnetic herad slider).

Magnetic anisotropy is created by applying a magnetic field in the direction of arrow B in the figure during plating. Good magnetic film? ' can be completely aligned in the direction of magnetization with a magnetic field of several Oersteds, but due to the presence of the non-magnetic plating frame 1, magnetic charges shown by + and - in FIG. 9 are generated at the ends of the magnetic film. A demagnetizing field (indicated by arrow C) is generated in a direction that cancels the magnetic field. A strong magnetic field of 100 Oe or more is required to overcome the demagnetizing field and align the magnetization.

The demagnetizing field increases rapidly as the track width W becomes smaller, and when the track width is 108 m, the plating magnetic field needs to be 1 Oe or more. It is extremely difficult to apply such a strong magnetic field to the entire large-scale plating bath for mass production.

The present invention provides a manufacturing method that facilitates mass production of thin film magnetic heads by reducing the demagnetizing field generated by the plating frame.

The present invention is characterized in that the width of the portion of the magnetic film formed at the same time as the magnetic core and removed when the magnetic head is completed is made larger than the track width.

In a magnetic core having the shape shown in FIG. 1, the demagnetizing field is thickest near the gear lug where the positive and negative magnetic charges are closest. The magnitude of the demagnetizing field when the magnetization is completely saturated by the plating magnetic field is determined when the track width W is 10 μm and 15 μm.
The results calculated as a function of position are shown in FIGS. 2(a), (b) and (C) for the cases of m and 25 μm, respectively. However, it is assumed that the film thickness is 2 μm, the width of the 7 beams is 5 μm, and an infinitely long magnetic film has a saturation magnetic flux density of 10,000 Gauss (FIG. 3(d)). From this result, in order to overcome the demagnetizing field and align the magnetization of 50q6 of the film, in the case of a track width of 10 μm, approximately 1 oersted and de are required; In the case of 25 μm, approximately 250 oersteds is sufficient.

The present invention is based on the above results, and makes it possible to obtain an effect similar to that obtained by widening the track width isometrically with respect to the demagnetizing field.

A first embodiment of the invention is shown in FIG. A portion 6 extending in the plating magnetic field application direction is provided below the floating surface A-A' which is removed when the magnetic head is completed. The length of this portion 6 in the plating magnetic field application direction is preferably 25 μm or more, more preferably 50 μm or more. Due to the function of this portion 6, the track width is, for example, 10 μm.
Even in this case, it was calculated that if the distance between the 10 and - magnetic poles is 5 .mu.m, a plating magnetic field of about 500 oersted would be sufficient to saturate the area.

Note that this portion 6 can be used to connect the two magnetic core layers to enable inductance testing in wafer state.

A second embodiment of the invention is shown in FIG. In this example, everything below the gap portion is a continuous magnetic film. In this case, a continuous portion 7 connects the two magnetic core layers to perform inductance testing in the wafer state.

As explained above, the present invention reduces the L demagnetizing field by making the magnetic layer extending downward from the gap part wider than the track width, thereby providing a head with strong magnetic anisotropy and fast magnetization switching. There is an effect obtained under a weak magnetic field.

[Brief explanation of the drawing]

Figure 1 shows a conventional magnetic core, Figures 2 (a) to (d)
) is a graph showing the relationship between track width and demagnetizing field size,
FIG. 3 is a diagram showing the first embodiment, and FIG. 4 is a diagram showing the second embodiment. 1... Plating frame, 3-=°°° Part of magnetic core 14... Gap portion. Section 3 Figure 4

Claims (1)

[Claims] A thin film head manufacturing method in which a magnetic core is manufactured using an electroplating method, characterized in that the width of the portion of the magnetic film that is formed at the same time as the magnetic core and is removed when the magnetic head is completed is larger than the track width. A method for manufacturing a thin film head.