JPH08124121A - Magneto-resistive thin-film magnetic head and its production - Google Patents

Abstract

PURPOSE: To improve wear resistance by forming a magnetic shield of an Ni-Fe-P alloy or Ni-Fe-B alloy. CONSTITUTION: This magnetic head has, successively from a substrate 1 side, an undercoat 2, a lower magnetic shield 3, a lower insulating film 4, a magneto-resistance effect element 5, a magnetic domain control film 8, an insulating film 9 for regulating a track width, an electrode 10, an upper insulating film 11, an upper magnetic shield 12 and a protective film 13 in this order. The magneto-resistive element 5 as a magnetic flux sensing part is held by the upper and lower magnetic shields 12, 3 in order to shield the magnetical noises from outside and is exposed on the floating surface facing a magnetic disk 30. The upper and lower magnetic shields 12, 3 consist of soft magnetic materials, such as Ni-Fe-P alloy. The upper and lower insulating films 11, 4 consisting of Al oxide which has electrically insulating characteristics and is nonmagnetic are interposed on the magneto-resistive element 5 and the upper and lower magnetic shields 12, 3. The magnetic domain control film 8 is formed on both sides of the magneto-resistive element 5 in order to turn the magnetic domain structure of the magneto-resistance effect element 5 into a magnetic monodomain and to suppress the noises occurring in magnetic walls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive thin film magnetic head suitable for high recording density magnetic recording and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, hard disks, which are auxiliary storage devices for computers, are becoming smaller and higher in recording density. Along with this miniaturization, instead of a magnetic head that detects a magnetic field using magnetic induction electromotive force, a magnetoresistive thin film magnetic head that detects a magnetic field using a magnetoresistive effect has been actively studied. . When using magnetically induced electromotive force, changes in the magnetic field per time are detected as voltage, whereas the magnetoresistive effect uses the phenomenon that electrical resistance changes in the magnetic field, and can be detected even in static magnetic fields. Is.

In a hard disk, when the diameter of the magnetic disk is reduced, the peripheral speed is decreased, so that the relative speed between the magnetic head and the magnetic disk is decreased. An increase in the number of rotations can be considered to increase the relative speed, but there is a limit. Therefore, when the size is reduced, a decrease in the relative speed between the magnetic head and the magnetic disk cannot be avoided. When the magnetic induction electromotive force is used, since the time change of the magnetic field is detected, the signal output decreases as the relative velocity decreases. On the other hand, the magnetoresistive thin film magnetic head utilizing the magnetoresistive effect is suitable for miniaturization because the signal output does not depend on the relative speed.

FIG. 4 (a) is a structural view of the magnetoresistive thin film magnetic head as seen from the air bearing surface side, and FIG. 4 (b) is the IV-
FIG. 4 is a structural cross-sectional view showing a cross section taken along line IV together with a magnetic disk. The magnetic head 31 includes an undercoat 2, a lower magnetic shield 3, a lower insulating film 4, a magnetoresistive effect element 5, electrodes 10, 10, an upper insulating film 11, an upper magnetic shield 12, and a protective film 13 from the substrate 1 side. Prepare for this order. The magnetoresistive effect element 5 as a magnetic flux sensing section is sandwiched between the upper and lower magnetic shields 12 and 3 for shielding magnetic noise from the outside, and is exposed on the air bearing surface facing the magnetic disk 30. There is. Further, between the magnetoresistive effect element 5 and the upper and lower magnetic shields 12 and 3, in order to electrically insulate them and form a magnetic gap, an electrically insulating non-magnetic aluminum oxide is used. Upper and lower insulating film 1
1, 4 are interposed.

[0005]

Generally, the magnetic head 31 and the magnetic disk 30 on the air bearing surface are normally operated.
Separated by 0.05 to 0.1 μm. In the method called CSS (contact start stop),
When stopped, the magnetic head 31 and the magnetic disk 30 come into contact with each other. In either method, it is not possible to avoid contact between the magnetic head 31 and the magnetic disk 30 due to vibration or other causes during operation. Further, the flying height tends to decrease with the increase in recording density, and the magnetic head 31 and the magnetic disk 30 come into contact with each other quite frequently.

When the magnetic head 31 and the magnetic disk 30 come into contact with each other, the magnetoresistive effect element 5, which is exposed on the air bearing surface 5,
The metal films of the upper and lower magnetic shields 12, 3 are scraped off by friction. Then, when the scraps of the upper and lower magnetic shields 12, 3 adhere to the magnetoresistive effect element 5, the electrodes 10, 10, they cause a short circuit. Many of the materials used for the upper and lower magnetic shields 12 and 3 are soft magnetic metal materials such as permalloy (Ni-Fe alloy), which has a proven record in magnetic heads of magnetic induction electromotive force, and these are easily scratched. The thickness of the magnetoresistive effect element 5 is thin (0.015 to 0.03 μm) for the purpose of increasing the detection sensitivity, but the upper and lower magnetic shields 12 and 3 are designed to effectively shield the external magnetic field. Thicker than a few μm
It is a degree. The upper and lower magnetic shields 12, 3 are electrodes 1
When it is short-circuited with 0 or 10 or the magnetoresistive effect element 5, the upper and lower magnetic shields 12 and 3 have low electric resistance, so that the sensitivity for detecting the electric resistance of the magnetoresistive effect element 5 which is a part for detecting a magnetic field becomes low. . Therefore, the upper and lower magnetic shields 12,
It can be seen that No. 3 is important in wear resistance.

As a countermeasure against this, Japanese Patent Laid-Open No. 2-116009 discusses the use of sendust, which is less likely to wear than permalloy, as a magnetic shield material. However, since sendust requires high temperature heat treatment, it can be used for the lower magnetic shield 3, but the magnetoresistive effect element 5
It cannot be used for the upper magnetic shield 12 which is formed after the formation. Permalloy is more cost-effective than sputtering
It can be formed by using a plating method which is excellent in terms of film forming temperature and shape manufacturing process, but sendust has a problem that it is difficult to manufacture by a plating method.

Further, it is conceivable to use a material having an electrically insulating property and a magnetically soft magnetic property for the upper and lower magnetic shields 12, 3. Specific examples include soft magnetic ferrite, which is an electrically insulating oxide magnetic material. Generally, when forming a magnetic shield with ferrite, there are a sintering method and a sputtering method, but the sintering method requires high-temperature heat treatment and is not practical. Further, the sputtering method is not preferable in terms of cost and manufacturing process as described above. Therefore, it is practically less practical than permalloy. In addition, Co-based amorphous is not practical because the plating method cannot be applied.

Since the magnetoresistive thin-film magnetic head cannot be written, it is often used in combination with a head using a magnetic induction electromotive force. Therefore, it is more cost effective to use materials and manufacturing processes. Up,
The film thicknesses of the lower magnetic shields 12 and 3 are substantially the same in both magnetic heads. Materials that cannot use the plating method have a problem in standardizing the manufacturing process.

Abrasion resistance is important even in a magnetic head using magnetically induced electromotive force, and it has been studied to improve the abrasion resistance by adding a third element to permalloy. However, the magnetic pole of the magnetic head using the magnetically induced electromotive force requires a high writing ability, and thus the material requires a high saturation magnetic flux density. Since the saturation magnetic flux density decreases when the third element is added to permalloy, it is not actually used for the magnetic head using the magnetic induction electromotive force. For this reason, materials that have not been used in magnetic heads using magnetically induced electromotive force are currently not used in magnetoresistive thin-film magnetic heads.

The present invention has been made in view of such circumstances, and a Ni-Fe-P alloy or a Ni-Fe-B alloy is used as a material of a magnetic shield, and a film is formed by a plating method. An object of the present invention is to provide a magnetoresistive thin-film magnetic head capable of improving abrasion resistance and a method of manufacturing the same, without being disadvantageous in process and cost as compared with the case of using permalloy.

[0012]

In the magnetoresistive thin-film magnetic head according to the present invention, the magnetic shield is Ni-Fe-P.
An alloy or a Ni-Fe-B alloy.

A method of manufacturing a magnetoresistive effect thin film magnetic head according to the present invention comprises a Ni--Fe--P alloy or a Ni--Fe--.
It is characterized in that the B alloy is formed by a plating method to form a magnetic shield.

[0014]

The upper and lower magnetic shields of the magnetoresistive thin-film magnetic head need only shield unnecessary magnetic flux leaking from the magnetic medium, and are as high as required in a magnetic head using magnetically induced electromotive force. No saturation flux density is required. Therefore, the material of the upper and lower magnetic shields only needs to have sufficiently high magnetic permeability even if the saturation magnetic flux density is low. It is known that the addition of P or B to permalloy improves the hardness and corrosion resistance. When P or B is added, the crystal grain size is reduced and hardness and corrosion resistance are improved. In particular, when they are made extremely finely crystallized or made amorphous, these are further improved. Further, the heat treatment further increases the hardness. If the heat treatment temperature is high, recrystallization partially occurs and the magnetic properties deteriorate, so
A temperature lower than the recrystallization temperature is desirable.

The Ni-Fe-P amorphous alloy plating and its properties are described in "Surface Technology, vol.40, No.3, 1989". The greater the content, the more amorphous it becomes, and the hardness and corrosion resistance are further improved. Furthermore, “Surface Technology, vol.
44, No. 6, 1993 ”, amorphous Ni-Fe-
It describes the conditions for producing a film and the range of amorphization when a P alloy is produced.

In the present invention, materials for the upper and lower magnetic shields are selected based on these documents and various studies. Since a material obtained by adding P or B to this permalloy is used to form the upper and lower magnetic shields by the plating method, the manufacturing process in the magnetic head using the magnetic induction electromotive force can be diverted. It can be manufactured without being disadvantageous in terms of process and cost as compared with the conventional one.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a perspective view showing a magnetoresistive thin film magnetic head according to the present invention, and FIG. 2 is an explanatory view showing each film separately. From the substrate 1 side, the undercoat 2, the lower magnetic shield 3, the lower insulating film 4, the magnetoresistive effect element 5, the magnetic domain control film 8, the track width defining insulating film 9, the electrode 1
0, 10, an upper insulating film 11, an upper magnetic shield 12, and a protective film 13 are provided in this order.

Magnetoresistive element 5 as a magnetic flux sensing section
Are sandwiched between the upper and lower magnetic shields 12 and 3 in order to shield magnetic noise from the outside.
It is exposed on the air bearing surface facing 0. The upper and lower magnetic shields 12 and 3 in the present invention are made of a soft magnetic material such as Ni-Fe-P alloy or Ni-Fe-B alloy. Further, between the magnetoresistive effect element 5 and the upper and lower magnetic shields 12 and 3, upper and lower insulating films 11 and 4 made of aluminum oxide which is electrically insulating and non-magnetic are interposed. The magnetic domain control film 8 is provided on both sides of the magnetoresistive effect element 5 in order to make the magnetic domain structure of the magnetoresistive effect element 5 into a single magnetic domain and suppress the generation of noise due to the domain wall. Further, the track width can be processed more accurately by using the track width defining insulating film 9 than by defining the track width by the distance between the electrodes 10. In FIG. 1, the protective film 13 and the terminal 14
Is not shown.

Next, a method of forming the upper and lower magnetic shields 12, 3 by plating will be described. FIG. 3 is a schematic diagram showing the configuration of a plating apparatus used for forming the upper and lower magnetic shields 12, 3. In the figure, 21 is a plating tank. The plating bath 21 is preferably made of a material such as acrylic resin that is non-conductive and non-magnetic and does not react with the acid plating bath. Materials such as vinyl chloride resin, polypropylene and Teflon resin may be used. In the prototype example shown below, a rectangular plating tank made of acrylic resin is used. And wafer 2
The cathode 23 to which 2 is mounted is below the plating tank 21,
The anode 24 is arranged above the plating tank 21.

An insoluble material such as platinum is also used as the anode material, but usually the same as the elemental metal or alloy metal to be plated is most desirable. In the case of alloy plating, a single metal having the same element as one of the alloy elements may be used unless an alloy plate having the same composition is available. In the following prototype example, a Ni plate (2 mm thick) containing a slight amount of sulfur is used. The temperature, pH, and concentration of the plating solution are controlled in the adjusting tank 25, and the plating solution is sent to the plating tank 21 by the pump 27 while adjusting the flow rate by the flow rate adjusting valve 26. The overflowed plating solution is recovered and sent to the adjusting tank 25 again. A permalloy alloy film is previously formed as a base on the wafer 22 set on the cathode 23 by a sputtering method.

Prototype Example 1. A prototype example using Ni-Fe-P alloy for the upper and lower magnetic shields 12 and 3 will be described. Table 1 shows the components of the plating solution. Plating current 5mA /
cm ² and pH was adjusted to 2.5 ± 0.01 with hydrochloric acid, the temperature of the plating solution was adjusted to 45 ± 0.1 ° C. using an electronic thermostat using a Peltier element, and the flow rate of the plating solution to the plating tank 21 was adjusted. The average was 5 liters per minute.

[0022]

[Table 1]

Prototype example 2. A prototype example using Ni-Fe-B alloy for the upper and lower magnetic shields 12 and 3 will be described. Table 2 shows the components of the plating solution. Plating current 1mA /
cm ² , pH adjusted to 3.5 ± 0.01 with hydrochloric acid, the temperature of the plating solution adjusted to 40 ± 0.1 ℃ using an electronic thermostat using a Peltier element, and the flow rate of the plating solution into the plating tank is average. It was 5 liters per minute.

[0024]

[Table 2]

Comparative Example. Also, the upper and lower magnetic shields 12, 3
Comparative example using Ni-Fe alloy (Permalloy) for
And explain. Table 3 shows the components of the plating solution. Electroplating
Flow 3mA / cm ²And adjust the pH to 3.0 ± 0.01 with hydrochloric acid
However, the temperature of the plating solution is an electronic thermostat using a Peltier element.
Adjust to 22 ± 0.1 ℃ using the equipment and then mount it in the plating tank.
The flow rate of the sewage was 5 liters per minute on average.

[0026]

[Table 3]

The above-mentioned three kinds of plating films are formed at 250 ° C.
After 30 minutes of heat treatment, the hardness of each plated film was measured using a Vickers hardness meter. The measurement results are shown in Table 4 together with the plating film composition.

[0028]

[Table 4]

From Table 4, the hardness of the plated film using the Ni-Fe-P alloy is about 50% higher than that of the conventional plated film using the Ni-Fe alloy.
In the plated film using B alloy, the increase is nearly 100%. From this, it is understood that the plating film using the Ni-Fe-P alloy or the Ni-Fe-B alloy is suitable for the magnetic shield.

[0030]

As described above, according to the present invention, a Ni-Fe-P alloy or a Ni-Fe alloy is used as a magnetic shield material.
-By using B alloy and forming a film by the plating method,
Compared with the case of using permalloy, it is possible to improve wear resistance without being disadvantageous in terms of process and cost.
The present invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a perspective view showing a magnetoresistive effect thin film magnetic head according to the present invention.

2A and 2B are explanatory views separately showing respective films constituting the magnetoresistive thin film magnetic head shown in FIG.

FIG. 3 is a schematic diagram showing a configuration of a plating apparatus.

FIG. 4 is a structural diagram showing a conventional magnetoresistive thin film magnetic head.

[Explanation of symbols]

 1 Substrate 3 Lower Magnetic Shield 4 Lower Insulating Film 5 Magnetoresistive Element 8 Magnetic Domain Control Film 9 Track Width Specification Insulating Film 10 Electrode 11 Upper Insulating Film 12 Upper Magnetic Shield 31 Magnetic Head

Claims (2)

[Claims] 1. A magnetoresistive effect thin-film magnetic head in which both sides of a magnetoresistive effect material are sandwiched by magnetic shields for shielding magnetic external noise, wherein the magnetic shield is a Ni--Fe--P alloy or A magnetoresistive effect thin-film magnetic head comprising a Ni-Fe-B alloy. 2. A method of manufacturing a magnetoresistive thin-film magnetic head in which both sides of a magnetoresistive material are sandwiched by magnetic shields in order to shield magnetic external noise.
A method of manufacturing a magnetoresistive thin-film magnetic head, comprising forming a magnetic shield by depositing a Ni-Fe-P alloy or a Ni-Fe-B alloy by a plating method.