JPS5928213A - Production of magneto-resistance effect type magnetic head - Google Patents

Abstract

PURPOSE:To improve both frequency characteristics and sensitivity, by forming consecutively the 1st ferromagnetic film for production of the 1st magneto- resistance effect element, an insulated layer for an intermediate insulated layer and then the 2nd ferromagnetic film for the 2nd magneto-resitance effect element and then etching collectively all those layers to form them into a desired shape respectively. CONSTITUTION:An Al-Cu alloy layer of 500Angstrom thickness and a Ti layer of 1,000Angstrom are formed on a substrate 3 as an adhered layer. Then a lower shielding layer 5 of NiFe, an insulated layer 7 of SiO2, the 1st ferromagnetic film 100 of NiFe which serves as the 1st magneto-resistance effect element, an insulated layer 4 of SiO2, and the 2nd ferromagnetic film 200 of NiFe which serves as the 2nd magneto-resistance effect element with thickness 2mum, 0.3mum, 500Angstrom , 0.3mum and 500Angstrom respectively. Then the films 100 and 200 and the layer 4 are formed collectively into a shape shown by 300 in the figure by an ion milling process (a dry etching process in which an Ar ion, etc. are accelerated and irradiated to a matter to perform a cutting process, etc.).

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a magnetic recording device, and particularly to a reproduction-only magnetic head included in a magnetic tape device or a magnetic disk device.

(b) Background of the technology Thin-film magnetic heads are being used as magnetic recording devices become more densely recorded. Among these, magnetic heads that utilize the magnetoresistive effect have a simple structure and Since a relatively large output signal can be obtained, it is expected to be put to practical use as a reproduction-only IS.

(C) Prior Art and Problems In a magnetoresistive magnetic head, the magnetization of a ferromagnetic film formed with the axis of easy magnetization aligned in a certain direction is controlled by an external magnetic field (for example, recorded on a magnetic recording medium) that passes near the ferromagnetic film. This method utilizes the phenomenon that the resistance of the ferromagnetic film changes depending on the magnetic signal).

In such a magnetoresistive magnetic head, as shown in FIG. 1, two magnetoresistive elements l and 3 made of a ferromagnetic film such as NiFe are mounted on a non-magnetic substrate 3 made of glass or 8102, etc. 2 for example 5i0
A type in which a current is applied in the same direction to each magnetoresistive element 1 and 2 through an insulating layer 4 consisting of two magnetoresistive elements, and the two magnetoresistive elements apply a bias magnetic field to each other by this current. There is.

In FIG. 1, 5 and 6 are a lower shield layer and an upper shield layer, respectively, and both are made of, for example, NiFe.
7 and 8 are insulating layers made of, for example, 5j02, which electrically insulate the shield layers 5 and 6 and the magnetoresistive elements I and 2; A recording medium such as a magnetic disk that travels in the direction of the arrow.

In the magnetoresistive magnet 71 shown in FIG.
The direction of the bias magnetic field applied to each other by the magnetoresistive elements 1 and 2 is 180 degrees as shown by the broken line arrow in FIG.
The opposite axis is reversed.

By the way, in general, in a magnetoresistive element, the highest sensitivity is obtained when the angle between the direction of magnetization and the direction of current flowing through the magnetoresistive element is around 45 degrees. Therefore, by appropriately selecting the current i flowing through the magnetoresistive elements 1 and 2 in FIG. The angle of the magnetoresistive element can be set at around -45 degrees, and the other magnetoresistive element can be set at around -45 degrees.

In this way, the magnetoresistive magnetic head of this type does not require an external bias magnetic field. Further, as shown in FIG. 3(A), the output signal R1 of the first magnetoresistive element 1 and the output signal R2 of the second magnetoresistive element 2 in response to the external magnetic signal S have opposite polarities, If the difference is calculated using a differential amplifier, a larger output signal R can be obtained than when only one magnetoresistive element is used, as shown in FIG. 3(B).

In FIG. 3 (A'), curve C shows the relationship between the resistivity (ρ) of the magnetoresistive element and the angle (θ) formed by the direction of magnetization with respect to the direction of current, and 60 m indicates the resistivity. This is the maximum value of change.

Now, when manufacturing a magnetoresistive magnetic head of the type described above, conventionally, a ferromagnetic material is used to form the shield layer 5, the insulating layer 7, and the first magnetoresistive element 1 on the substrate. After the films are sequentially formed, the ferromagnetic film is etched by photoetching to form the first magnetoresistive element 1 having a pattern as shown in FIG. Thereafter, the insulating layer 4 and a ferromagnetic film for forming the second magnetoresistive element 2 are formed thereon, and a second film having the same shape as the magnetoresistive element 1 is formed by photo-etching.
A magnetoresistive element 2 is formed.

In this type of magnetoresistive magnetic head, it is desirable that the thickness of the insulating layer 4 be as small as possible from the viewpoint of frequency characteristics and sensitivity.

However, according to the above-mentioned conventional manufacturing process, the incorporation or adhesion of dust during the etching process for forming the first magnetoresistive element 1 or between this process and the subsequent film forming process of the insulating layer 4 can be avoided. Therefore, as the thickness of the insulation N4 becomes smaller, defects such as dielectric breakdown occur more frequently.Also, the film formation of the magnetoresistive element 2 is affected by the residue of the photoresist used in the photoetching process. When the substrate becomes uneven, and the edge profile of the molded magnetoresistive element 2 becomes non-uniform, deterioration of magnetic properties such as demagnetizing field becomes insufficient is likely to occur. In addition, since the magnetoresistive elements 1 and 2 are molded separately, there are drawbacks such as pattern misalignment between them, which tends to cause the same deterioration of magnetic properties as described above, which also reduces the yield of the product. This also had the disadvantage of increasing production costs.

(d) Object of the Invention It is an object of the present invention to provide a method for manufacturing a magnetoresistive magnetic head that eliminates the drawbacks of the conventional manufacturing methods described above and has excellent frequency characteristics, sensitivity, and economical efficiency.

(e) Structure of the Invention The present invention provides a method for manufacturing a magnetoresistive magnetic head in which two magnetoresistive elements are provided adjacent to each other with an intermediate insulating layer interposed therebetween, in which a first magnetoresistive element is formed. After sequentially forming a first ferromagnetic film for forming a first ferromagnetic film, an insulating layer for forming an intermediate insulating layer, and a second ferromagnetic film for forming a second magnetoresistive element, , are characterized in that they are etched all at once and molded into a desired shape.

(f) Examples of the invention Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 and subsequent figures are diagrams for explaining a preferred embodiment of the present invention, in which (A) is a plan view and (B) is a cross-sectional view of the portion indicated by a dashed line in (A). In these figures, the same parts as in the previously published figures are given the same reference numerals.

In FIG. 5, an 81-Cu alloy layer with a thickness of 500 mm is formed on the substrate 3 as an adhesion layer (a layer for increasing the adhesion strength between the substrate 3 and the lower seal 13 layer 5 to be formed subsequently). After forming a Ti layer with a thickness of 1,000 mm and 1,000 mm (both are not shown), a lower shield layer 5 made of NiFe is formed with a thickness of 2 mm.
The insulating layer 7 made of 5i02 has a thickness of 0.3 μm.
The first ferromagnetic film 100, which is made of N1ce and becomes the first magnetoresistive element, has a thickness of 500 mm and a thickness of 5i02.
A second ferromagnetic film 200 made of NiFe and serving as a second magnetoresistive element is formed to have a thickness of 500 μm.

In the steps up to this point, the insulating layers 4 and 7 made of 5i02 are generally sputtered to form the other adhesion layers - the upper shield layer 5, the ferromagnetic material II! The layers 1i100 and 200 are formed by sputtering or vapor deposition, and can be formed without being taken out into the atmosphere each time each layer is formed.

In FIG. 5, the ferromagnetic film 200 is shown formed by photoetching into the shape indicated by hatching in FIG. This is because the ferromagnetic film 200 is removed in advance to avoid the extraction window, and high pattern accuracy is not required.

Next, ion milling (a dry etching method in which accelerated Ar ions, etc. are irradiated onto the object to perform processing such as cutting)
The ferromagnetic films 100 and 200 and the insulating layer 4 are
It is molded all at once into the shape shown at 300 in the figure.

Through the steps up to this point, the ferromagnetic films 100 and 20
0 are formed into almost the final shape of the magnetoresistive elements 1 and 2, respectively.

Subsequently, as shown in FIG. 7, excess portions of the lower shield layer 5 and the insulating layer 7 are removed by ion milling. As shown in FIG. 8, an insulating layer 8 made of 5i02 is formed over the entire surface to a thickness of 0.3 μm, and then an upper shield layer 6 made of NiFe is formed on a part of the surface to a thickness of 2 μm. A film is formed in a band shape.

As roughly shown in FIG. 9, a protective layer 1 made of 5i02
After forming a film of 0 to a thickness of 1 μm over the entire surface, the insulating layer in the terminal extraction windows 11 and 12 is removed by photoetching, and the terminal portions of the magnetoresistive elements 1 and 2 are exposed.

Terminal extraction windows 11 and 12 provided as described above
Terminal layers 13, 14 and 15 made of A1 or the like are provided as shown in FIG. 10 so as to be electrically connected to the terminal portions of magnetoresistive elements 1 and 2 through the terminal layers. Note that the terminal layer 15
is a common terminal commonly connected to one terminal portion of each of the magnetoresistive elements 1 and 2.

Finally, the magnetoresistive elements 1 and 2 are formed into the final shape shown in FIG. 4 by cutting along the line X-X in FIG. 10 and polishing the cut surfaces. An effective magnetic head is completed.

It goes without saying that if a magnetic substrate such as ferrite is used in place of the non-magnetic substrate 3 in the above, the formation of the lower shield layer 5 can be omitted and the process can be simplified.

(g) Effects of the Invention According to the present invention, the thickness of the insulating layer between two magnetoresistive elements can be made smaller than the thickness of approximately 0.5 μm when using conventional manufacturing methods. In addition, it is possible to make the edge profiles of these magnetoresistive elements uniform and eliminate any deviation in their mutual overlap, thereby providing a magnetoresistive magnetic head with large reproduction output and excellent frequency characteristics. There is an effect that can be done.

Furthermore, compared to conventional methods, it is possible to improve product yield by zero and reduce the number of steps, which has the effect of providing a low-cost magnetic head.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the basic configuration of a magnetoresistive magnetic head provided with two magnetoresistive elements, and Figs. 2 and 3 show the operation of the magnetoresistive magnetic head having the configuration shown in Fig. 1. FIG. 4 is a schematic diagram showing an example of the shape of the magnetoresistive element in the magnetoresistive magnetic spatula shown in FIG. 1, and FIGS. FIG. 3 is a schematic diagram for explaining the manufacturing process of such a magnetoresistive magnetic head. In the figure, 1 and 2 are magnetoresistive elements, 3 is a substrate, 4, 7 and 8 are insulating layers, 5 is a lower shield layer, 6 is an upper shield layer, 9 is a recording medium, 1O is a protective insulating layer, 1
1 and 12 are terminal extraction windows, 13, 14 and 15 are terminal layers, 100 and 200 are ferromagnetic films, and 300 is the shape of a magnetoresistive effect element which is molded all at once. 1

Claims (1)

[Claims] In a method of manufacturing a magnetoresistive magnetic head in which two magnetoresistive elements are provided adjacent to each other via an intermediate insulating layer, a first ferromagnetic film for forming a first magnetoresistive element; After successively forming an insulating layer for forming an intermediate insulating layer and a second ferromagnetic film for forming a second magnetoresistive element, they are etched all at once to form a desired pattern. A method for manufacturing a magnetoresistive magnetic head characterized by molding it into the shape of