JPS6233414A - Manufacture of magnetically soft material film - Google Patents

Abstract

PURPOSE:To reduce the irregularity in characteristics generating when the titled magnetic film is manufactured as well as to suppress the generation of Barkhausen noise, the fluctuations in reproduced output and the deterioration in high frequency characteristics by a method wherein a plurality of rectilinear grooves are formed on the second magnetically soft material film, an annealing treatment is performed on the first and the second magnetically soft material films, and then the second magnetically soft material film is removed. CONSTITUTION:A non-magnetic thin film 3 is laminated on the first magnetically soft material film 2, a number of grooves 5 extending in Y-direction are formed rectilinearly, and then the second magnetically soft material film 4 consisting of a soft magnetic amorphous alloy, permalloy and the like is formed on the grooves 5. Subsequently, an etching is performed collectively on the first an the second magnetically soft material films 2 and 4 and the non- magnetic thin film 3 based on the rectilinear direction (Y-axis direction) of the grooves 5, and they are formed into the prescribed core shape. Then, an annealing treatment is performed on the laminated material of the first and the second magnetically material films 2 and 4 at the prescribed temperature for the stipulated period of time. Subsequently, the second magnetically soft material film 4 is removed by performing an etching and the like, and the manufacture of magnetically soft material film having the easily magnetizable axes A and E in the prescribed direction for the core shape is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a soft magnetic film used in magnetic transducers such as magnetic sensors and magnetic converters.

Conventionally, various magnetic transducers using soft magnetic films have been used to write and read magnetic information on magnetic storage media such as magnetic tapes and magnetic disks. It has been known.

For example, the purpose of a soft magnetic film used in inductive thin film magnetism is to effectively converge signal magnetic flux from a magnetic storage medium and link it to a coil. The purpose of the soft magnetic film used in the magnetic shield of a magnetoresistive magnetic head known as a flux-responsive magnetic head is to block unnecessary magnetic fields and improve reproduction resolution. For these purposes, soft magnetic films are required to have high magnetic permeability and good frequency characteristics. Therefore, the soft magnetic film is generally given −axis anisotropy, and its shape and positional relationship with the magnetic storage medium should be optimally designed so that the signal magnetic flux is guided parallel to its axis of hard magnetization.

On the other hand, a magnetic head designed to introduce signal magnetic flux in the direction of the easy axis of magnetization of a soft magnetic film can obtain high magnetic permeability in the low frequency region, but as the frequency of the signal magnetic flux increases, the permeability increases. The magnetic flux sharply decreases, and as a result, the signal magnetic flux interlinking with the coil also decreases, resulting in a sharp attenuation of the reproduction output. Furthermore, Barkhausen noise and fluctuations in reproduction output due to movement of domain walls and changes in the shape of magnetic domains are also observed.

As mentioned above, in a magnetic transducer using a soft magnetic film, uniaxial anisotropy is imparted to the soft magnetic film, and signal magnetic flux is directed parallel to the axis of hard magnetization (that is, in a direction orthogonal to the axis of easy magnetization). It is an essential condition to obtain good characteristics.

Conventionally, as a method of imparting -axis anisotropy to such soft magnetic films, soft magnetic films are formed on a substrate in a uniform magnetic field using techniques such as vacuum evaporation, sputtering, taring, and electrodeposition. A film is formed, or after film formation, annealing is performed in a uniform magnetic field to generate an axis of easy magnetization parallel to the magnetic field, and -
It was given axial orientation. Thereafter, the soft magnetic film formed on the substrate is processed into a core pattern shape having a predetermined arrangement relationship with the axis of easy magnetization using photolithography technology to form other functional parts such as a coil. It was completed as a magnetic transducer.

However, in the above manufacturing process, the arrangement relationship Vi between the core shape of the soft magnetic film and its axis of easy magnetization does not match the setting Vi, and variations occur. This is because the easy axis direction of magnetization is not necessarily uniform over the entire surface of the substrate due to non-uniform magnetic field distribution and film quality when imparting -axis anisotropy. Also, when processing the soft magnetic film into a core shape, the misalignment with the axis of easy magnetization is also 11! I can pass. These are the resulting characteristics of the magnetic transducer? This resulted in dullness and a decrease in manufacturing yield.

Furthermore, it has been disclosed that the path of the signal magnetic flux and the axis of hard magnetization are not necessarily parallel throughout the entire soft magnetic film core (for example, in the 6th Japanese Society of Applied Magnetics Academic Lecture Abstracts, 1982). , Lecture No. 17aB-10). It has a curved core shape that allows the signal magnetic flux that flows into the magnetic storage medium from one end of the soft magnetic film to pass through the film surface and returns to the magnetic storage medium from the other end.

Therefore, since the signal magnetic flux path is curved, in the method for manufacturing soft magnetic thin films using the uniform magnetic field described above, there is a region where the axis of easy magnetization coincides with the direction of the signal magnetic flux, resulting in deterioration of frequency characteristics and Barkhausen This resulted in the generation of noise and fluctuations in the playback output.

On the other hand, in order to control the disturbance of the magnetic domain shape and the movement of the domain walls, a method has been disclosed for magnetism using a soft magnetic film in which many thin grooves are formed (Japanese Patent Application Laid-Open No. 185013-1989).
). Since the domain walls of the small soft magnetic film are aligned in the direction of the groove, the signal magnetic flux propagates through the magnetization rotation. Therefore, movement of domain walls and changes in magnetic domain shape due to signal magnetic flux are suppressed. However, the presence of a large number of grooves results in a substantial increase in the magnetic resistance of the soft magnetic film, which significantly attenuates the signal magnetic flux. This results in a significant decrease in the reproduction output as a magnetic field.

(Purpose of the invention) The object of the present invention is to solve the above-mentioned conventional drawbacks.

There is little variation in characteristics during manufacturing, and there is little crystallization of Barkhausen noise due to domain wall movement and changes in magnetic domain shape, and less of the 11 easy rC effect on the output! An object of the present invention is to provide a method for manufacturing a soft magnetic film with suppressed k.

Furthermore, another object of the present invention is to provide a method for manufacturing a soft magnetic film that has good characteristics even when the magnetic flux path is curved.

(Structure of the Invention) According to the present invention, a step of laminating a first and a second soft magnetic film through a non-magnetic thin film at an interval that allows magnetostatic coupling, and At least in one aspect, the first
forming a plurality of grooves perpendicular to the direction of signal magnetic flux passing through the soft magnetic film; annealing the first and second soft magnetic films; and removing the second soft magnetic film. There is obtained a method for manufacturing a soft magnetic film characterized by comprising:

(Detailed Description of Configuration) The present invention solves the problems of the prior art by using the above-mentioned manufacturing method. That is, in the present invention, by forming a plurality of linear grooves on the second soft magnetic film, the demagnetizing field in the direction perpendicular to the grooves is increased and the magnetization thereof is aligned in the direction of the grooves. Moreover, since the tenth soft magnetic film is stacked with the second soft magnetic film through the nonmagnetic thin film at an interval that allows magnetostatic coupling with the second soft magnetic film, the first soft magnetic film has the second soft magnetic film. The magnetization is aligned parallel to the magnetization of the soft magnetic film. Therefore, by annealing the first and second soft magnetic films in a stable state, the magnetization capacitance JAIIJ1 parallel to the linear direction of the plurality of grooves is
It is possible to generate a uniaxial shell pattern with w. Thereafter, by removing the second magnetic film, a soft magnetic film having an axis of easy magnetization parallel to the linear direction of the groove is completed.

Therefore, since the direction of the linear groove can be uniquely determined based on the core shape of the soft magnetic film, the direction of the -axis anisotropy is uniquely determined according to the core shape of the soft magnetic film. This eliminates the variations in characteristics that occur when manufacturing soft magnetic cores in bulk on the same substrate, and even with a curved core pattern, the signal can be transmitted throughout the signal magnetic flux path. A soft magnetic film with a hard axis of magnetization parallel to the direction of magnetic flux is realized.

Hereinafter, the present invention will be explained in more detail with reference to the drawings. It is a schematic perspective view showing the manufacturing process of the 1st bean paste invention.

first,! ! In FIG. 1(b), a soft magnetic amorphous alloy (for example, 0oZrs Co'[
'a etc. Co-meta A,! The first soft magnetic film 2 made of a high a magnetic material such as amorphous or permalloy is formed by a method such as sputtering, taring, vacuum deposition, or electrodeposition. A non-magnetic thin film 3 is laminated on the first soft magnetic film 2, and a large number of grooves 5 are formed on the surface of the non-magnetic thin film 30 in the y-axis direction using techniques such as photolithography and ion etching. Form into a straight line that extends to . Next, the corresponding number of #! A second soft magnetic film 4 made of soft magnetic amorphous alloy, permalloy, etc. is formed on J5. Therefore, the first and second soft magnetic films 2 and 4 and the non-magnetic thin film 3 are etched all at once on the non-magnetic thin film 3 with the seed line direction (y-axis direction) as a reference, into a predetermined core shape. . In FIG. 1, the core is processed into a strip-shaped core extending in the X-axis direction for the purpose of passing the signal magnetic flux in the X-axis direction.

The thickness of the non-magnetic thin film 3 is selected within a range that allows magnetostatic coupling between the first and second soft magnetic films 2 and 4. for example,
A thickness of about 100AB to several μm is preferable. Further, the material of the non-magnetic thin film 3 is selected to be a material that does not cause thermal diffusion with the first and second soft magnetic materials M2 and 4. For example, Ti, TaSM
Conductive materials such as 5i02 and insulating materials such as Alt03.5ilN are preferable.

On the other hand, the thickness of the second soft magnetic film 4 is determined according to the thickness and saturation magnetization of the first soft magnetic film 2.

In other words, a rough guideline is to set the thickness of the second soft magnetic film and the saturation magnetization s-b to be approximately equal to the product of the thickness of the first soft magnetic film and the saturation magnetization. .

In the manufacturing process up to this point, the magnetization of the second soft magnetic film 4 is aligned in the longitudinal direction (y-axis direction) of the groove 5. This is because if the magnetization is directed in the linear direction (X-axis direction) of the groove 5, it will be formed and generated by the groove 5, and the demagnetizing field will increase. Therefore, the magnetization of the second soft magnetic film 4 is reduced to the groove 5.
In order to align more stably in the linear direction of the
The demagnetizing field in the X-axis direction may be set large by decreasing the pitch of the grooves 5 or increasing the depth of the grooves 5.

Furthermore, since the magnetization of the second soft magnetic film 4 is aligned in the linear direction (y-axis direction) of the groove 5, magnetic charges are generated at both ends of the second soft magnetic film 4 in the y-axis direction. . The magnetic charge induces negative-sign magnetic charges at both ends of the first soft magnetic film s2 in the y-axis direction, causing the magnetization of the first soft magnetic film 2 to be antiparallel to the direction of magnetization of the second soft magnetic FIX4. Excite to. That is, the magnetization of the first soft magnetic film 2, like the magnetization of the second soft magnetic film 4, is aligned in the y-axis direction and is stable in that direction.

As a subsequent step, the first and second soft magnetic films 2 and 4 are
0II! The i-layer body is annealed under predetermined time and temperature conditions. The conditions for the annealing treatment are that the first soft magnetic film 2
The material is selected according to the material. In other words, if an amorphous soft magnetic material is used, if it is a polycrystalline material such as a crystal dust alloy, the temperature at which grain growth will not occur (300 -
An annealing temperature of 400° C. or less is desirable. Further, it is preferable that the annealing treatment be performed in a vacuum or in a hydrogen or nitrogen gas atmosphere. This prevents deterioration of magnetic properties due to oxidation of @1 and the second soft magnetic films 2 and 4.

As a result of the above annealing process, the magnetization of the first soft magnetic film 2 is aligned in the linear direction (y-axis direction) of the groove 5, so y
Uniaxial anisotropy is generated having an easy axis of magnetization E-A% in the axial direction and a hard axis of magnetization in the X-axis direction.

As the next step, a second soft magnetic film 4 is formed.

Remove by ching etc. As shown in FIG. 1(b), this is done by etching the non-magnetic thin film 3 all at once.
Only the first soft magnetic film 2 may be left.

Through the steps described above, a soft magnetic film having easy magnetization axes E and A in predetermined directions with respect to the core shape is completed.

In FIG. 1, when forming the unevenness (grooves) in the second soft magnetic film 4, a large number of grooves 5 are formed in the non-magnetic thin film 3 in advance, and the unevenness of the grooves 5 is formed in the second soft magnetic film. Although it is transferred to the film 4, the second
As shown in the schematic perspective view shown in the figure, directly on the second soft magnetic film 4,
A large number of linear grooves 5 may be formed. In FIG. 2, the first soft magnetic film 2 is easily magnetized parallel to the linear direction (y-axis direction) of the groove 5 by going through the same manufacturing process as explained using FIG. 1. Uniaxial anisotropy with axes E and A can be generated. In the case of Figure 1, the non-magnetic thin film 3)! While y is also defined by the depth of the groove 5,
In FIG. 2, since the groove 5 is formed on the second soft magnetic film 4, the thickness of the non-magnetic thin film 3 is not limited by the groove 5. Therefore, since the thickness of the nonmagnetic thin film 3 can be set extremely thin, the magnetostatic coupling between the first and second soft magnetic films 2 and 4 can be further strengthened. Moreover, in Fig. 2, if a method such as sputtering or tlX vaporized N is used,
Since the first soft magnetic film #2, the non-magnetic thin film 3, and the second soft magnetic film 4 can be successively formed in the same vacuum system, the manufacturing process is simpler than in the case shown in Fig. 1. become.

Further, FIG. 3 shows the core shape of a soft magnetic film suitable for applying the present invention. FIG. 3 shows a core of a soft magnetic film having a horseshoe-shaped curved magnetic flux path, and FIG. 3(a) is a plan view thereof;
FIG. 3(b) is a diagram showing the A-λ cross section of FIG. are sequentially laminated and processed into a horseshoe-shaped core shape.A large number of linear grooves 5 are formed on the surface of the second soft magnetic film 4 in a direction perpendicular to the curved magnetic flux path.

In the manufacturing process up to this point, the second soft magnetic film 4 has a large demagnetizing field in the direction orthogonal to the groove 5, so its magnetization should be aligned in the linear direction of the groove 5. That is, the magnetization of the second soft magnetic film 4 is aligned in the direction perpendicular to the magnetic flux path over the entire curved core. Furthermore, the magnetization of the first soft magnetic film 2 is also fixed in the direction perpendicular to the magnetic flux path due to the magnetostatic coupling with the second soft magnetic film 4. In this state, the first
By performing the same annealing treatment as explained using the figures, an axis of easy magnetization perpendicular to the path of the signal magnetic flux is formed in the first soft magnetic film 2 over the entire curved core. Thereafter, by removing the second soft magnetic film 4, a soft magnetic film having easy magnetization perpendicular to the path of the signal magnetic flux throughout the core is completed (not shown).

In FIG. 3, as well, the method of forming unevenness on the second soft magnetic film 4 is to form grooves in the nonmagnetic thin film 3 and transfer the unevenness to the second soft magnetic film, as in FIG. It's okay.

(Example) Hereinafter, specific materials and annealing conditions of the present invention will be explained using an example using the core shape shown in FIG.

In FIG. 3, as the first soft magnetic film 2, 0o90%
An amorphous soft magnetic film having a composition of -'I'alO% (at%) is made to a thickness of 0.5 μm, a non-magnetic thin film [3 is made of Ti to a thickness of 0.02 μm, and a second soft magnetic film 4 is made of Ni82. A permalloy film having a composition of %-Fe18% (wt%) was continuously formed to a thickness of 1 μm by sputtering. These laminates were processed into a horseshoe-shaped pattern with f @ 50 μm using the IJ lithography technique, and formed on the surface of the second soft magnetic film with an average pitch of 5 μm and a depth of 0.5 μm.
A laminated body of soft magnetic films in which a large number of grooves 5 of 5 μm in diameter were formed in a direction perpendicular to the horseshoe curve was heated to 250° C. in a vacuum, and this state was maintained for 4 hours.

After the above-mentioned annealing step, the second soft magnetic film 4 was removed using an etching solution containing ferric chloride as a main component to complete the core pattern of the soft magnetic film.

The magnetic domains of the soft magnetic film of this embodiment of the present invention are
When observed by the method, domain walls were observed in the direction perpendicular to the horseshoe curve throughout the core pattern, and it was confirmed that the axis of easy magnetization was generated in the direction perpendicular to the magnetic flux path. Furthermore, a coil was formed using photolithography technology so as to surround the core pattern of the soft magnetic film, and a magnetic transducer was fabricated such that both ends of the horse-shaped six-shaped pattern served as input and output ends of the signal magnetic flux. However, the noise is small, from low frequency to 10
It was confirmed that a uniform signal output was obtained over a high frequency of M& or higher, and that the device had excellent high frequency characteristics.

(Comparative Example) For comparison, a soft magnetic film having the same core pattern as the example of the present invention but not subjected to the manufacturing process according to the present invention was fabricated, and when magnetic domains were observed, the pattern was An irregular arrangement of domain walls such as buckling domains was observed throughout the area. Furthermore, when a magnetic transducer similar to the embodiment of the present invention is manufactured, although a relatively large signal output can be obtained at a signal flux frequency of several hundred KHz or less, there is an extremely large amount of noise and the frequency becomes high. As time passed, a sharp decrease in signal output was observed.

(Effects of the Invention) As explained above, in the present invention, the core pattern of the soft magnetic film has a multilayer structure of soft magnetic films with non-magnetic thin films interposed therebetween, and the grooves formed on one side of the soft magnetic film are directed in the linear direction. The axis of easy magnetization of the other soft magnetic film can be formed in this manner. Therefore, by forming the grooves in the direction perpendicular to the signal magnetic flux path on the core pattern, a core pattern of a soft magnetic film having an axis of easy magnetization perpendicular to the signal magnetic flux path can always be manufactured. As a result, when mass-producing soft magnetic film core patterns,
Since the misalignment in the direction of the magnetization axis can be eliminated, a soft magnetic film with extremely small variations in properties and high yield can be obtained. Moreover, since the groove can be formed in any direction, the path of the signal magnetic flux and the axis of easy magnetization can always be perpendicular to each other.
Even with a core pattern of n, a soft magnetic film with excellent frequency characteristics and low noise is obtained.

Furthermore, since no grooves are formed in the soft magnetic film that serves as the magnetic flux path, the increase in magnetic resistance and the attenuation of the signal magnetic flux due to the presence of the grooves can be extremely minimized.

FIG. 2 is a schematic perspective view for explaining another embodiment of the present invention, FIG. 3 (a) and (b) are a schematic perspective view for explaining another embodiment of the present invention, and FIGS. FIG. 2 is a plan view and a cross-sectional view for explaining.

In the figure, 1... base body, 2... first soft magnetic film,
3... Non-magnetic thin film, 4... Second soft magnetic film, 5...
·groove.

1cm+i -xtTIn-+- inside W! jFigure 1 1. Base (b) Figure 2 IP 1. Base Figure 3 (a) 1. Base

Claims (1)

[Claims] a step of laminating first and second soft magnetic films via a non-magnetic thin film at intervals that allow magnetostatic coupling; and a step of laminating the first soft magnetic film on at least one surface of the second soft magnetic film. forming a plurality of grooves perpendicular to the direction of the signal magnetic flux passing therethrough;
A method for manufacturing a soft magnetic film, comprising the steps of annealing the first and second soft magnetic films, and removing the second soft magnetic film.