JPH0354709A - Method and device for manufacturing thin film magnetic head - Google Patents

Abstract

PURPOSE:To prevent the degradation of characteristics caused by the history of heat and to enlarge the margin degree of temperature control at the time of heat treatment by executing the heat treatment on plural stages composed of the first and second heat treatment, etc., for which the impressing direction of a magnetostatic field is different. CONSTITUTION:A non-crystalline magnetic film is formed to be a magnetic core constituting a magnetic path. Next, the first heat treatment is executed at a Curie point lower than a crystallizing temperature in a non-magnetic field or in the magnetostatic field in the same direction as the magnetic path. Further, the second heat treatment is executed at the Curie point lower than the crystallizing temperature in the magnetostatic field in the direction rectangular to the magnetic path. Thus, in the second heat treatment to be executed while impressing the magnetostatic field in the direction orthogonal to the magnetic path of the magnetic core, a rapid change is suppressed in anisotropic energy and the margin degree is enlarged in the temperature control of the heat treatment. Further, it is possible to suppress the degradation caused by the history of heat for the characteristics such as relative magnetic permeability, etc., in the magnetic core.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technology for manufacturing a thin film magnetic head, and in particular to a technology that is effective when applied to a technology for forming a magnetic core using a poor quality alloy film or the like.

[Conventional technology]

For example, in response to the demand for improved information recording density on magnetic surface recording media such as magnetic disks and magnetic tapes,
In addition to improvements such as increasing the coercive force of the magnetic materials constituting the recording medium, efforts are being made to increase the number of tracks by further narrowing the track interval, which is the information recording area.

For this reason, as a magnetic head for recording and reproducing information on a magnetic recording medium with a narrow track interval, instead of the conventional bulk type magnetic head, a head structure with fine IJ dimensions has been developed using well-known photo IJ lithography technology. Thin-film magnetic heads that can be realized and have good high-frequency characteristics of recording/reproducing signals have come to be used.

By the way, the material of the magnetic core constituting the magnetic circuit in such a thin-film magnetic head was initially mainly a NrFe-based (neu-malloy) crystalline alloy, but due to the high coercive force of the recording medium, Co-based amorphous alloys with higher saturation magnetic flux density,
Fe-based crystals and the like have come to be used.

However, although Co-based non-quality alloys exceed permalloy in terms of saturation magnetic east density, they have the drawback of large magnetic anisotropy energy and low relative magnetic permeability. At the time of formation, a magnetic field was applied to intentionally impart magnetic anisotropy, and the magnetic film was further heat-treated in the magnetic field. On the other hand, like this! ! Thin-film magnetic heads using manufactured non-quality magnetic films have small magnetic anisotropy energy and good responsiveness to recording/reproduction signals, but there is a problem in that the reproduction output deteriorates significantly over time. , for example, Japanese Patent Application Publication No. 1983-1980
There is a technique disclosed in Publication No. 9.

That is, when processing a magnetic thin film that has been given magnetic anisotropy during film formation into a magnetic core, the direction of easy magnetization of the magnetic thin film is aligned with the magnetic path direction, and a static magnetic field is applied in a direction perpendicular to the magnetic path. However, by performing heat treatment below the Curie point and crystallization temperature, the direction of magnetic anisotropy in a certain film can be rotated 90 degrees from the initial state, and the high-frequency characteristics in the plane orthogonal to the easy magnetization direction can be changed. By aligning the good direction of difficult magnetization with the direction of the magnetic path, it is attempted to suppress deterioration of the reproduced output over time.

[Problem to be solved by the invention]

However, in a technology that simply performs a one-step heat treatment like the above-mentioned conventional technology, when the magnetic thin film is subjected to thermal history after obtaining the desired magnetic anisotropy energy, the magnetic anisotropy energy that has been carefully set is lost. There is an inconvenience that the relative magnetic permeability deteriorates again.

In order to avoid this, it is necessary to perform heat treatment to rotate the axis of easy magnetization at a temperature as high as possible below the Kikory point and crystallization temperature, but the higher the heat treatment temperature, the more the magnetic anisotropy increases. Changes in energy become steeper,
Margin in temperature control during actual manufacturing
The problem was that it became smaller.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a thin-film magnetic head that can prevent the characteristics from deteriorating due to heat filff, increase the margin of temperature control during heat treatment, and obtain accurate heat treatment results. There is a particular thing.

Another object of the present invention is to provide an apparatus for manufacturing a thin-film magnetic head that can efficiently carry out heat treatment in multiple stages in which magnetic fields are applied in different directions.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, the method for manufacturing a thin film magnetic head according to the present invention is as follows:
The first step is to form an amorphous magnetic film that becomes the magnetic core constituting the magnetic path, and the first step is to form an amorphous magnetic film that becomes the magnetic core constituting the magnetic path.
The second step is a heat treatment, and the third step is a second pA treatment at a temperature below the Curie point and crystallization temperature in a static magnetic field perpendicular to the magnetic path.

Further, the thin film magnetic head manufacturing apparatus according to the present invention includes a magnetic field forming means for forming a static magnetic field, a heating furnace arranged with an axis perpendicular to the static magnetic field, and a heating furnace for holding a workpiece. It consists of a holding jig that is inserted inside and a rotation mechanism that is connected to this holding jig and rotates the object to be processed in a desired direction and at a desired angle with respect to the direction of the static magnetic field. be.

[Effect]

According to the method for manufacturing a thin film magnetic head of the present invention described above,
As will be described later, for example, by going through the first heat treatment, rapid changes in the anisotropic energy during the second heat treatment, which is performed while applying a static magnetic field in a direction perpendicular to the magnetic path of the magnetic core, are suppressed, and the heat treatment It is possible to increase margin in temperature control and the like, and to suppress deterioration of characteristics such as relative magnetic permeability in the magnetic core due to thermal history.

This makes it possible to easily and accurately control the heating temperature in the second heat treatment, and for example, to accurately control the magnetic anisotropy energy by rotating the axis of easy magnetization by 90 degrees in the second heat treatment. As a result, it is possible to obtain a thin film magnetic head whose reproduction characteristics are less degraded over time.

Further, according to the thin film magnetic head manufacturing apparatus of the present invention, the first and second heat treatments in which the static magnetic field is applied in different directions can be performed without taking out the object to be processed, such as the substrate on which the thin film magnetic head is formed, from the heating furnace. Since multiple stages of heat treatment can be performed continuously, it is possible to shorten the time required for heat treatment work and reduce the required man-hours, and it is possible to efficiently perform multiple stages of heat treatment in which static magnetic fields are applied in different directions. For example, productivity in the manufacturing process of thin film magnetic heads can be improved.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a method and apparatus for manufacturing a thin film magnetic head according to an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram illustrating an example of a method for manufacturing a thin film magnetic head, which is an embodiment of the present invention, and FIG. 2 shows an example of the structure of an apparatus for manufacturing a thin film magnetic head that implements the method. It is a partially cutaway perspective view.

First, the structure of the thin film magnetic head manufacturing apparatus in this embodiment will be explained with reference to FIG. 2 and the like.

A cylindrical heating furnace 2 is placed on top of the pedestal 1 with its axis substantially horizontal. It can be heated to a temperature of

An electromagnet 3 and an electromagnet 4 are arranged at positions sandwiching the heating furnace 2 from above and below, and a desired direction is placed inside the heating furnace 2 located between them in a direction orthogonal to the axial direction of the heating furnace 2. The structure is such that a strong static magnetic field H is generated.

An exhaust pipe 2a connected to an exhaust mechanism such as a vacuum pump (not shown) is provided at one sealed end of the cylindrical heating furnace 2, and the inside of the heating furnace 2 can be evacuated to a desired degree of vacuum. is possible.

In this case, the other end of the heating furnace 2 is closed by a rotating mechanism 5 consisting of, for example, a removably connected step motor. A holding jig 7 is supported via a rotating shaft 6 made of a heat-resistant material and extending in the internal axial direction of the holding jig 2 .

A plurality of substrates 8 are stably held in this holding jig 7 in an attitude in which a plane on which a thin film magnetic head M (described later) is formed is orthogonal to the axis of the heating furnace 2 . By controlling the rotation angle of the drive shaft 5a in the rotation mechanism 5 according to commands from the outside at any time, the angle between the flat surface of the substrate 8 held by the holding jig 7 and the static magnetic field H is adjusted to a desired value. It is set to the value.

The operation of the support mechanism 5 and the temperature raising and lowering operations in the heating furnace 2 are controlled by a control computer (not shown) based on a predetermined program.

Then, by a series of operations as described below, a plurality of thin film magnetic heads M having a cross-sectional structure as shown in FIG. 6, for example, are collectively formed on the plane of the substrate 8.

That is, the thin film magnetic head M in this embodiment has the sixth
As shown in the figure, a lower magnetic core 8a is deposited on a substrate 8 made of a non-magnetic material, and an end of the lower magnetic core 8a is
a and an upper magnetic core 8b whose other end overlaps with a gap layer 8C having a thickness corresponding to the size of the target gap G.

FIG. 7 is a schematic plan view showing the lower magnetic core 8a and the upper magnetic core 8b taken out, and as shown in the figure, the lower magnetic core 8a and the upper magnetic core 8b are arranged from the connecting end side to the gap G side. It has a shape in which the width dimension gradually decreases, and the direction thereof is the magnetic path direction 9.

Further, on the substrate 8, a conductor coil formed in a spiral shape, for example, is provided so as to intersect with a magnetic path constituted by a lower magnetic core 8a and an upper magnetic core 8b whose ends are connected to each other. A pattern 8d is arranged.

Furthermore, an interlayer film 8e is interposed between the conductive coil pattern 8d and the upper magnetic core 8b.

An example of a manufacturing method in this embodiment of the thin-print magnetic head M having the structure as described above will be described below.

First, for example, C 0
92T a4 Z r. A magnetic thin film, which will become the lower magnetic core 8a, is deposited by a method such as sputtering.

In this sputtering process, for example, as shown in FIG. 7, a magnetic field of a predetermined strength is applied in the same direction as the direction 9 (final direction of difficult magnetization 11), and the formed magnetic thin film is uniaxially different. Give direction.

Next, the magnetic thin film thus formed (lower magnetic core 8a
) is attached to the holding jig 7, and
It is loaded into the heating furnace 2 as shown in FIG.

Then, the rotation mechanism 5 is rotated as appropriate, and as shown in FIG. (That is, the orientation of the substrate 8 is set to be the same as the final difficult magnetization direction 11), and in that state, in a predetermined atmosphere, while applying a static magnetic field H, for example,
Stabilization heat treatment (first heat treatment) is performed at 00° C. for a predetermined time t1 (for example, 1 hour).

Thereafter, the heating temperature in heating φ2 is set to 350° C., and the rotation mechanism 5 is operated to rotate the substrate 8 held by the holding jig 7 by 90 degrees from the current posture, and the static magnetic field H The direction is set so that the direction is orthogonal to the magnetic path direction 9, that is, the final easy magnetization direction 10 shown in FIG. Improvement heat treatment (second heat treatment)
I do.

FIG. 3 shows an example of the measurement results of the processing time t2 of this characteristic improving heat treatment and the change in magnetic anisotropy energy Hk.

In the figure, line a shows the change in magnetic anisotropy energy Hk when the stabilizing heat treatment as in this example is not performed, and line b shows the change when the stabilizing heat treatment is performed.

Further, the vertical axis of the figure shows the magnetic anisotropy energy Hk in the final hard magnetization direction 11 at the bottom and the magnetic anisotropy energy Hk in the final easy magnetization direction 10 at the top. That is, as shown in the figure, in the characteristic improvement heat treatment, the direction of difficult magnetization is rotated by 90 degrees with respect to the magnetic path direction 9 during the treatment process, and is intentionally set to be perpendicular to the magnetic path direction at the beginning. The set direction of difficult magnetization most likely coincides with the final direction of difficult magnetization 11.

From the figure, it is known that the slope of line a, which is not subjected to stabilization processing, is steeper than that of line b, which is also subjected to stabilization processing.

That is, for example, the relative magnetic permeability of the lower magnetic core 8a is set to 10.
Considering the case where a property improvement heat treatment is performed so that the magnetic anisotropy energy Hk becomes 7 or less in order to make it 00 or more, it is better to perform a stabilization heat treatment before the property improvement heat treatment as in this example. Changes in the anisotropy energy Hk become gradual, and the time margin for temperature control during property improvement heat treatment becomes larger, so that the value of the magnetic anisotropy energy Hk is within the target range during the temperature raising process of the substrate 8. There is no need to worry about deviating from the standard.

This makes it possible to obtain the desired and accurate heat treatment result for the magnetic thin film (lower magnetic core 8a).

In this way, the substrate 8 that has undergone the characteristic improvement heat treatment is transferred to the heating furnace 2.
The lower mwt core 8a is formed into the desired shape by performing a process such as ion milling on the magnetic thin film taken out from the magnetic thin film and coated thereon.

After that, a gap layer 3c is formed on the upper part of the lower magnetic core 8a, etc.
, a conductor coil pattern 8d, an interlayer film 8e, etc. are formed, and a magnetic thin film that will become the upper magnetic core 8b is formed using the same magnetic material and procedure as the lower magnetic core 8a described above.

Next, the substrate 8 on which the magnetic thin film that is to become the upper magnetic core 8b is formed is mounted on the holding jig 7 and loaded into the heating furnace 2.

Then, by appropriately controlling the rotating mechanism 5, as shown in FIG. 8
Set the rotation posture of.

Then, under a predetermined high degree of vacuum and application of a static magnetic field H,
Temperature 250°C lower than that of the lower magnetic core 8a described above
A stabilizing heat treatment (first heat treatment) is performed in which the substrate is heated for a predetermined time t3 (for example, one hour).

Furthermore, the board 8 is rotated by 90 degrees from the current posture,
The same 25
Characteristic improvement heat treatment (second heat treatment) is performed at 0° C. for a predetermined time t4.

Here, FIG. 4 shows the desired relative magnetic permeability (for example, 1000
The lower magnetic core 8
It shows the results of measuring changes in relative magnetic permeability when heat treatment equivalent to the thermal history experienced by a was performed at different heating temperatures of 250°C, 300°C, and 350°C.

From the same figure, it is known that the higher the heating temperature is, the more remarkable the decrease in relative magnetic permeability is.In the heat treatment of the upper magnetic core 8b formed after the lower magnetic core 8a, the heating temperature is lowered as in this example. It can be seen that this setting is extremely effective from the viewpoint of preventing deterioration of the relative magnetic permeability of the lower magnetic core 8a that has already been formed.

Further, FIG. 5 is a diagram comparing and showing changes in relative reproduction output over time in the method for manufacturing the thin film magnetic head in this embodiment described above and the method for manufacturing the conventional thin film magnetic head.

That is, in the same figure, lines f and h line the axis of easy magnetization during formation of the magnetic thin film in the magnetic path direction 9 (the final direction of difficult magnetization 1
1), and then heat-treated to increase the magnetic anisotropy to 9.
This is the case where a magnetic core obtained by rotating the core by 0 degrees is used, and the line f is the case where stabilization heat treatment is performed before the property improvement heat treatment as in this example, and the line h is the conventional case where the stabilization heat treatment is not performed. The case is shown below.

In addition, lines g and j in the same figure indicate that the easy magnetization axis of the magnetic thin film is made in a direction perpendicular to the magnetic path direction 9 of the magnetic core (final easy magnetization direction 10), and the subsequent characteristic improvement heat treatment is performed for only a short time. , the magnetic anisotropy energy is simply reduced without changing the direction of the magnetic anisotropy. Among these, line g shows the case where the stabilizing heat treatment as in this example was performed, and line J shows the case where the stabilizing heat treatment was not performed.

That is, as is clear from the figure, when forming a magnetic thin film as in this example, the axis of easy magnetization is made to be the same as the magnetic path direction 9 (final direction of difficult magnetization 11), and by stabilizing heat treatment and property improving heat treatment, When the magnetic anisotropy is rotated by 90 degrees so that the most difficult direction of magnetization 11 coincides with the magnetic path direction 9, the deterioration over time of the reproduction output of the thin film magnetic head M is the smallest, and the deterioration over time of the reproduction output is minimized. It turns out that it is extremely effective in prevention.

Furthermore, even if the direction of magnetic anisotropy is not rotated by heat treatment, it is known that performing stabilization heat treatment prior to characteristic improvement heat treatment as in this example is effective in preventing deterioration of the reproduced output over time. It will be done.

Further, according to the thin film magnetic head manufacturing apparatus of the present embodiment described above, stabilization heat treatment and characteristic improvement heat treatment in different directions of the applied static magnetic field H are performed on the substrate 8 from the heating furnace 2 each time. Since it can be carried out continuously without taking out the heat treatment process, the time and man-hours required for the heat treatment process are reduced.
Productivity in the manufacturing process of thin film magnetic heads is improved.

In addition, since the much lighter side of the board 8 is rotated relative to the heavier electromagnet, the rotation mechanism 5 is simplified.
It is possible to reduce the cost of manufacturing equipment.

In addition, in the description of the above embodiment, as an example of the process, a case is described in which a static magnetic field is applied in the process of forming the first magnetic thin film to impart magnetic anisotropy, but the present invention is not limited to this.
Even if sufficient magnetic anisotropy is not imparted to the magnetic thin film immediately after formation, the same effect can be obtained by applying a static magnetic field H in the same direction as the magnetic path direction 9 during the stabilization heat treatment process. can.

Further, the first heat treatment may be performed after the step of forming the magnetic core on the magnetic thin film.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the temperature and heating time in the stabilization heat treatment and property improvement heat treatment are not limited to those exemplified in the above embodiments.

Furthermore, it goes without saying that the magnetic material 1 constituting the upper magnetic core and the lower magnetic core is not limited to those exemplified in the above embodiments, but may be other types of amorphous alloys.

Further, the structure of the thin film magnetic head finally obtained is not limited to that exemplified in the above embodiments.

C Effects of the Invention Among the inventions disclosed in this application, effects obtained by typical inventions are briefly explained below.

That is, according to the method of manufacturing a thin-film magnetic head according to the present invention, the first step is to form a poor quality magnetic film that becomes a magnetic core constituting a magnetic path, and the first step is to form a magnetic film of poor quality, which becomes a magnetic core constituting a magnetic path, and a step of forming a magnetic film in the absence of a magnetic field or in the same direction as the magnetic path. a second step of performing a first heat treatment at a temperature below the Curie point and the crystallization temperature in a static magnetic field; and a third step of performing a second heat treatment at a temperature below the Curie point and the crystallization temperature in a static magnetic field perpendicular to the magnetic path. For example, by going through the first heat treatment, a sudden change in anisotropic energy during the second pigeon treatment, which is performed while applying a static magnetic field in a direction perpendicular to the magnetic path of the magnetic core, is suppressed. In addition to increasing the margin for temperature control during heat treatment,
Deterioration of characteristics such as relative magnetic permeability in the magnetic core due to thermal history can be suppressed.

This makes it possible to easily and accurately control the heating temperature in the second heat treatment, and for example, to accurately control the magnetic anisotropy energy by rotating the axis of easy magnetization by 90 degrees in the second heat treatment. As a result, it is possible to obtain a thin film magnetic head whose reproduction characteristics are less degraded over time.

Further, according to the thin film magnetic head manufacturing apparatus of the present invention, a magnetic field forming means for forming a static magnetic field, a heating furnace disposed with an axis perpendicular to the static magnetic field, and a workpiece to be processed are held. inside the heating furnace; a holding jig that is inserted; and a rotation that is connected to this holding jig and rotates the workpiece in a desired direction and at a desired angle with respect to the direction of the static magnetic field; It consists of a mechanism that allows for multiple stages of heat treatment, including first and second processes in which a static magnetic field is applied in different directions, to take out the workpiece, such as a substrate on which a thin film magnetic head is formed, from the heating furnace. It can be performed continuously, reducing the time and man-hours required for heat treatment work, and efficiently performing heat treatment in multiple stages in which the static magnetic field is applied in different directions.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating an example of a method for manufacturing a thin film magnetic head, which is an embodiment of the present invention, and FIG. FIG. 3 is a diagram showing the change in magnetic anisotropy energy during characteristic improvement heat treatment, comparing the manufacturing method of a thin film magnetic head according to an embodiment of the present invention with that of the prior art. FIG. 4 is a graph showing the deterioration of the relative magnetic permeability of the magnetic core due to thermal history in the case of various heating temperatures. FIG. Fig. 6 is a schematic cross-sectional view showing an example of the structure of a thin film magnetic head; Fig. 7 is a diagram showing the magnetic path direction, the final easy magnetization direction, and the final magnetization difficult direction. FIG. 1... Frame, 2... Heating furnace, 2a... Exhaust pipe, 3
．． 4... Electromagnet, 5... Rotating mechanism, 5a... Drive shaft, 6... Rotating shaft, 7... Holding jig, H... Static magnetic field, 8... Substrate, 8a...lower magnetic core, 8b...
- Upper magnetic core, 8C... gap layer, 8d... conductor coil pattern, 8e... interlayer film, G... gap, M... thin film magnetic head, 9... magnetic path direction, 10
... Final easy magnetization direction, 11... Final difficult magnetization direction, Hk... Magnetic anisotropy energy, t1... Time of first heat treatment for the lower 8 magnetic cores, t2... For the lower magnetic core Time for second heat treatment, t3... Time for first heat treatment on the upper magnetic core, t4... Time for second heat treatment on the upper magnetic core.

Claims (1)

[Claims] 1. A first step of forming an amorphous magnetic film that becomes a magnetic core constituting a magnetic path, and a step of forming an amorphous magnetic film at the Curie point and the magnetic core in the absence of a magnetic field or in a static magnetic field in the same direction as the magnetic path. A second step of performing a first heat treatment at a temperature below the crystallization temperature, and a third step of performing a second heat treatment at a temperature below the Curie point and the crystallization temperature in a static magnetic field perpendicular to the magnetic path. A method for manufacturing a thin film magnetic head. 2. When forming the magnetic film in the first step, an axis of easy magnetization is provided in the same direction as the magnetic path when later formed into the magnetic core. A method of manufacturing the thin film magnetic head described above. 3. By forming the lower magnetic film and the upper magnetic film before and after the conductor coil pattern formation step, when forming the magnetic core that interlinks with the conductor coil pattern, the upper magnetic film is formed. 3. The thin film magnetism according to claim 1, wherein the temperature of the first and second heat treatments on the magnetic film is lower than the temperature of the first and second heat treatments on the lower magnetic film. Head manufacturing method. 4. a magnetic field forming means for forming a static magnetic field; a heating furnace disposed with an axis perpendicular to the static magnetic field; and a holding jig inserted into the heating furnace while holding a workpiece; An apparatus for manufacturing a thin film magnetic head, comprising a rotation mechanism connected to the holding jig and rotating the object to be processed in a desired direction and at a desired angle with respect to the direction of the static magnetic field.