JPH1139614A - Magnetic head and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an insulating film having excellent dielectric breakdown characteristics even when the total thickness is decreased, and to provide an information memory device having high recording density. SOLUTION: When insulating films are formed on and under a magnetoresistance sensor(MR sensor), two kinds of oxides selected from alumina (Al2 O3 ), tantalum oxide (Ta2 O5 ), zirconium oxide (ZrO2 ), silicon oxide(SiO2 ), titanium oxide(TiO), hafnium oxide (HfO2 ) and niobium oxide(NbO5 ) are used. These two kinds of oxides are alternately deposited to plural layers 3a, 3b to obtain the specified total thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for reading information recorded on a magnetic recording medium by a magnetoresistive sensor utilizing a magnetoresistance effect, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As is well known, a conventional magnetic head for reading information recorded on a magnetic recording medium such as a magnetic disk using a magnetoresistance effect uses a magnetoresistance sensor (MR sensor). Have been.

When an MR sensor is used for a magnetic head, an inductive thin film head is used as a recording head, and an MR sensor is used as a reproducing head.

When using the magnetic head constructed as described above, a pair of insulating films are formed above and below the MR sensor, and a pair of magnetic shield members are formed on both sides of the insulating film. It is configured to eliminate magnetic fields other than magnetic fields.

As a material for the magnetic shield member, a thin film of a soft magnetic material such as permalloy (NiFe alloy) is used as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-116909. As a material for the pair of insulating films, aluminum oxide (alumina: Al2
O3) is used.

[0006]

With the recent increase in recording density of information storage devices such as magnetic disk devices, the thickness of the insulating film of a magnetic head using an MR sensor used for the information storage device has been reduced. However, when the thickness of the insulating film is reduced, the magnetic shield members provided above and below the insulating film and the MR sensor and the electrodes provided adjacent thereto are reduced. There is a problem that a dielectric breakdown easily occurs between the magnetic head and the magnetic head, and a magnetic head with poor insulation frequently occurs.

When an alumina film is used as a material for the insulating film, when the film thickness is 150 nm or more, the withstand voltage is about 2 × 10 7 (volt / cm). Markedly reduced, film thickness 70n
m, the withstand voltage is 5 × 10 6 (volts / c
m) and dielectric breakdown occurs only by applying a voltage of about 5 volts.

To form an alumina film, Al2
In general, a means for forming a film by sputtering using an O3 sintered body as a target is used. The characteristics (refractive index and dielectric strength) differ depending on the density and the density. Furthermore, impurities contained in the target material (especially Si
And the content of elements such as Mg), the characteristics of the formed insulating film change and the dielectric strength characteristics vary. For this reason, there is also a problem that it is difficult to stably obtain an alumina thin film having high withstand voltage characteristics.

[0009] It is an object of the present invention to provide a conventional MR as described above.
A magnetic head that eliminates the drawbacks of a magnetic head using a sensor and can stably obtain excellent withstand voltage characteristics even when the thicknesses of the insulating films on and under the MR sensor are reduced. It is to provide a method.

[0010]

According to the present invention, there is provided a magnetic head comprising:
In a magnetic head having a pair of insulating films provided above and below a magnetoresistive sensor, the pair of insulating films are alternately laminated in two or more layers of two types of inorganic insulating materials each having a predetermined thickness, and the whole is formed to have a predetermined thickness. In particular, two kinds of oxides of aluminum oxide, tantalum oxide, zirconium oxide, silicon oxide, titanium oxide, hafnium oxide, or niobium oxide are used as the two kinds of inorganic insulating materials; The ratio of the thickness of each step of the two types of inorganic insulating materials constituting the pair of insulating films is set in a range of 1: 1 to 1:10, and the thickness of the first insulating layer of the pair of insulating films In the range of 0.2 to 0.5 nm.

According to a method of manufacturing a magnetic head of the present invention, in the method of manufacturing a magnetic head in which a pair of insulating films are provided above and below a magnetoresistive sensor, the pair of insulating films may be formed of two types of inorganic materials each having a predetermined thickness. A plurality of insulating materials are alternately stacked to form a predetermined thickness as a whole. In particular, as the two types of inorganic insulating materials, aluminum oxide, tantalum oxide, zirconium oxide, silicon oxide, titanium oxide, or hafnium oxide Or using two kinds of oxides of niobium oxide, further using two kinds of materials of metal aluminum or metal tantalum or metal zirconium or silicon or metal titanium or metal hafnium or metal niobium as a target, In an atmosphere of a mixed gas of argon gas and oxygen gas The above two types of inorganic insulating materials are alternately stacked in a plurality of stages by performing co-sputtering, the gas pressure at the time of sputtering is set to 0.3 to 0.8 Pa, and the two types of insulating films constituting the pair of insulating films are formed. The thickness ratio of the inorganic insulating material is in the range of 1: 1 to 1:10, and the thickness of the first insulating layer forming the pair of insulating films is 0.2 to 0.5 nm.
The range is as follows.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the structure of the lower insulating film of the embodiment of FIG. 2, FIG. 2 is a sectional view showing an embodiment of the magnetic head of the present invention, and FIG. 3 is a lower insulating film of the embodiment of FIG. FIG. 4A is a characteristic diagram showing characteristics of a film and an upper insulating film together with characteristics of a lower insulating film and an upper insulating film of a conventional magnetic head. FIG. FIG. 4B is a characteristic diagram showing the dependency of the dielectric strength voltage characteristics on the gas pressure at the time of sputtering. FIG. 4 is a diagram showing the thickness of the first insulating film in the lower insulating film and the upper insulating film in the embodiment of FIG. The characteristic diagram showing the characteristics when the thickness is fixed and the thickness of the second insulating film is changed,
(A) is a characteristic diagram showing a chemical etching rate with respect to an alkali developing solution, (b) is a characteristic diagram showing a withstand voltage characteristic, and FIG. 5 is a first insulating film in the lower insulating film and the upper insulating film of the embodiment of FIG. FIG. 7A is a characteristic diagram showing characteristics when both the thickness of the film and the second insulating film are changed. FIG. 7A is a characteristic diagram showing a chemical etching rate with respect to an alkali developing solution, and FIG. FIG.

In the magnetic head of this embodiment, as shown in FIG. 2, a lower shield film 2 made of a magnetic material such as NiFe is formed on a substrate 1 made of a non-magnetic material.
The lower sensor 3 is laminated on the lower insulating film 3, and the MR sensor 5 formed in a predetermined shape is laminated at the center on the lower insulator 3.
A longitudinal bias film 4a and an electrode film 4b (longitudinal bias film / electrode film 4) are formed adjacent to both sides of the sensor 5, and an upper insulating film 6 is further laminated thereon.
An upper shield film 7 made of a magnetic material such as iFe is laminated,
A recording gap 8 is laminated on the upper shield film 7, a recording pole 9 is formed at a central portion above the recording gap 8, and the overcoat film 1 is formed on the recording pole 9 and the recording gap 8.
0 are stacked.

As shown in FIG. 1, the lower insulating film 3 is formed by alternately laminating a first insulating film 3a and a second insulating second film 3b in a plurality of steps using two different kinds of inorganic insulating materials. The thickness is a predetermined thickness. The upper insulating film 6 has the same configuration.

As the two kinds of inorganic insulating materials, aluminum oxide (alumina: Al 2 O 3), tantalum oxide (Ta 2 O 5) or zirconium oxide (Zr
O2), silicon oxide (SiO2), titanium oxide (TiO), hafnium oxide (HfO2), or niobium oxide (NbO5).

In order to form an insulating film of these oxides,
Metal aluminum (Al) or metal tantalum (T
a) or metal zirconium (Zr) or silicon (S
i) or two kinds of metal titanium (Ti), metal hafnium (Hf), or metal niobium (Nb) as a target, in an atmosphere of a mixed gas of an argon (Ar) gas and an oxygen (O2) gas. By performing co-sputtering, two types of inorganic insulating materials are alternately laminated. The ratio of the thickness of the two types of inorganic insulating materials is
The range is from 1: 1 to 1:10.

With this configuration, even if the entire film thickness of the lower insulating film 3 or the upper insulating film 6 is set to be as thin as 70 nm or less, it is possible to have excellent withstand voltage characteristics.

Hereinafter, aluminum oxide (alumina: Al2O3) is used as the first insulating film 3a, and the second insulating film 3a is used.
An example of the case where tantalum oxide (Ta2O5) is used as b will be described.

The thickness of the first insulating film 3a is d1, the thickness of the second insulating film 3b is d2, d1: d2 = 1: 1, d1 = d
2 = 0.3 nm, the metal aluminum (Al) target and the metal tantalum (T
a) Argon (Ar) gas 70 s using the target of a)
The film is formed in an atmosphere of a mixed gas of ccm and oxygen (O2) gas at 30 sccm. The power density for the target is 2 watts / cm for the Al target
2, 1 watt / cm 2 for a Ta target, and the number of rotations of the substrate was 0.1 mm for each layer of Al 2 O 3 and Ta 2 O 5 when the gas pressure during sputtering was changed. Adjust for each gas pressure so as to be 3 nm. The film formation time is such that the final overall film thickness is 50 nm.
Adjust so that

FIG. 3 shows the characteristics of the lower insulating film 3 (upper insulating film 6) when the gas pressure is changed within the range of 0.1 to 1.1 Pa under such conditions. Things
(A) is a diagram showing characteristics of a chemical etching rate (etching rate) with respect to an alkali developing solution, and (b) is a diagram showing a withstand voltage characteristic.

In FIG. 3A, a broken line 11 indicates the etching rate of the lower insulating film 3 (upper insulating film 6), and a broken line 12 indicates an Al2 film formed from a target of a conventional Al2 O3 sintered body. It is an etching rate characteristic in the case of an insulating film having a single O3 film.

As is clear from FIG. 3A, the etching rate of the insulating film of this embodiment decreases as the gas pressure increases, and becomes constant when the gas pressure is in the range of 0.3 to 0.8 Pa. After that, when the pressure becomes 0.9 Pa or more, the pressure rises again. However, as a whole, the value is lower than that of the conventional insulating film of the fold line 12, indicating that the chemical etching resistance is excellent.

In FIG. 3B, the broken line 13 is
The breakdown voltage characteristics of the lower insulating film 3 (upper insulating film 6) are shown, and the broken line 14 is the breakdown voltage characteristic of a conventional Al2O3 single-layer insulating film.

The withstand voltage characteristic of the insulating film of this embodiment shows a higher value as the gas pressure increases.
When it becomes Pa, it becomes a high value of 1 × 10 7 volt / cm. On the other hand, in the case of the conventional insulating film of the fold line 14, when the gas pressure is increased, the withstand voltage characteristics are slightly improved. However, even when the gas pressure is 0.9 Pa, the breakdown voltage is at most about 2.5 × 10 6 volt / cm. It's just

From these, Al2 O3 and Ta2 O5
The insulating film obtained by laminating the two types of insulating layers is Al2
It can be seen that the breakdown voltage characteristics and the chemical etching resistance are superior to those of the single-layer O3 film. In order to obtain an excellent insulating film, the gas pressure at the time of sputtering should be 0.3 to 0.8 P
a is desirable.

Next, a description will be given of the withstand voltage characteristics and the like of the embodiment when the thickness d1 of the first insulating film 3a is fixed and the thickness d2 of the second insulating film 3b is changed.

Also in this case, the material of the first insulating film 3a is Al2O3, and the material of the second insulating film 3b is Ta2O3.
5, in a mixed gas atmosphere of an argon (Ar) gas 70 sccm and an oxygen (O 2) gas 30 sccm, a film is formed at a power density of 2 watts / cm 2 for an Al target. The thickness of one layer of Al2O3 of the first insulating film 3a is 0.1 mm.
3 nm.

On the other hand, in order to change the thickness of Ta2O5 of the second insulating film 3b to 0.15 to 5 nm, the film is formed by changing the thickness of the Ta target in the range of about 1 to 16 Watt / cm2. . The ratio of the thickness d1 of the first insulating film 3a thus obtained to the thickness d2 of the second insulating film 3b is
It is in the range of 1: 1 to 1:16. The gas pressure during film formation is fixed at 0.5 Pa. The film formation time is adjusted so that the final overall film thickness becomes 50 nm.

FIG. 4 shows the characteristics of the lower insulating film 3 (upper insulating film 6) formed under such conditions.
(A) is a diagram showing characteristics of an etching rate with respect to an alkali developing solution, and (b) is a diagram showing a withstand voltage characteristic.

In FIG. 4A, the broken line 15 indicates the etching rate, and is as low as about 0.4 (angstrom / min) when the thickness of the Ta2O5 film of the second insulating film 3b is 3.75 nm or less. It can be seen that the etching rate rapidly deteriorates when the thickness exceeds 3.75 nm.

In FIG. 4B, the broken line 16 is
The dielectric breakdown voltage characteristics of the lower insulating film 3 are shown. When the thickness of Ta2O5 of the second insulating film 3b is within a range of 3.75 nm or less,
The withstand voltage characteristic shows a high value of 1 to 2.5 × 10 7 volt / cm, but when it exceeds 3.75 nm, the withstand voltage characteristic rapidly decreases.

From these, in order to obtain an insulating film having both excellent withstand voltage characteristics and chemical etching resistance, the thickness (d1) of one layer of Al 2 O 3 of the first insulating film 3a must be 0.3.
The thickness (d2) of one layer of Ta 2 O 5 of the second insulating film 3b is 0.15 to 3.75 nm (film thickness ratio 1:
0.5-1: 12.5). In consideration of a manufacturing margin, the thickness ratio between the first insulating film 3a and the second insulating film 3b is desirably in the range of 1: 1 to 1:10.

In the above embodiment, the first insulating film 3a is made of Al2
The thickness of O3 is 0.3 nm, and the thickness of Ta2 O5 of the second insulating film 3b is changed. The thickness of Ta2 O5 of the second insulating film 3b is 0.3 nm.
Even when the thickness of Al2O3 in the first insulating film 3a was changed, the ratio of the thickness of the first insulating film 3a to the second insulating film 3b was excellent in the range of 1: 1 to 1:12. It has been confirmed that an insulating film having a withstand voltage characteristic and a chemical etching resistance can be obtained.

Next, the thickness d1 of the first insulating film 3a is set to 0.1
A description will be given of the withstand voltage characteristics and the like of the embodiment in the case where the thickness is changed within the range of 0.6 nm and the thickness d2 of the second insulating film 3b is changed.

Also in this embodiment, Al2 O3 is used as the first insulating film 3a and Ta2 O5 is used as the second insulating film 3b. The Al2O3 film is formed by using an Al target in an atmosphere of a mixed gas of 70 sccm of argon (Ar) gas and 30 sccm of oxygen (O2) gas as a power density of 0.5 to 4 watts / target.
The first insulating film 3a has a thickness of A
The thickness (d1) of one layer of l2O3 is 0.1 to 0.
It is changed in a range of 6 nm.

On the other hand, Ta2 O5 of the second insulating film 3b is:
70 sc of argon (Ar) gas using a Ta target
In a mixed gas atmosphere of 30 cm and oxygen (O2) gas, a film is formed at a power density of 1 to 40 watts / cm2 with respect to a target.
The thickness (d2) of one layer of Ta2O5 of the second insulating film 3b is changed in the range of 0.15 to 12 nm.

The ratio of the thickness of each of the Al2O3 film and the Ta2O5 film thus obtained is 1: 0.5 to 1.0.
The range is 1:20. The gas pressure at the time of film formation is 0.
It is fixed at 5 Pa. The film formation time is adjusted so that the final overall film thickness becomes 50 nm.

FIG. 5 shows the characteristics of the lower insulating film 3 (upper insulating film 6) formed under such conditions.
(A) is a diagram showing characteristics of an etching rate with respect to an alkali developing solution, and (b) is a diagram showing a withstand voltage characteristic.

In FIG. 5A, a broken line 17 (symbol ●)
Is the thickness (d) of one layer of the first insulating film 3a (Al2O3).
When 1) is 0.1 nm, the broken line 18 (symbol △) is 0.2
In the case of nm, the broken line 19 (symbol ○) is 0.3 nm,
The broken line 20 (symbol □) is 0.4 nm, the broken line 21 (symbol ▽) is 0.5 nm, the broken line 22 (symbol ▲) is 0.
The characteristics of the etching rate in the case of 6 nm are shown. FIG.
From (a), the thickness (d1) of one layer of the Al2O3 film is set to 0.
When the thickness is 2 to 0.5 nm, the Al2O3 film and the Ta2O5
Although the ratio of the thickness of each layer of the film is in the range of 1: 0.5 to 1:12, it exhibits excellent chemical etching resistance,
3 When the film thickness (d1) is 0.1 nm and 0.6 nm, the chemical etching resistance is inferior.
When the thickness ratio of the O3 film / Ta2O5 film increases,
It can be seen that it gets worse.

The same applies to FIG. 5B.
2 (symbol ●) indicates a case where the thickness (d1) of one layer of the first insulating film 3a (Al 2 O 3) is 0.1 nm, a broken line 23 (symbol Δ) is 0.2 nm, and a broken line 24 (symbol ○). Is 0.3
In the case of nm, the broken line 25 (symbol □) is 0.4 nm,
The broken line 26 (symbol Δ) indicates the withstand voltage characteristics when the thickness is 0.5 nm, and the broken line 27 (symbol ▲) indicates the withstand voltage characteristics when the thickness is 0.6 nm. FIG.
From (b), when the thickness (d1) of one Al2O3 film of the first insulating film 3a is 0.2 to 0.5 nm, Al2O3
3 shows excellent withstand voltage characteristics when the thickness ratio of each Ta2 O5 film of the second insulating film 3b to that of the second insulating film 3b is in the range of 1: 0.5 to 1:12, but the thickness of the Al2 O3 film is Are 0.1 nm and 0.6 nm, the withstand voltage characteristics are inferior.
It can be understood that when the thickness ratio of the 2O3 film / Ta2O5 film is increased, the ratio is further deteriorated.

From these, to obtain an insulating film having both excellent withstand voltage characteristics and chemical etching resistance, the thickness of one layer of Al 2 O 3 of the first insulating film 3a must be 0.2 to 0.5.
nm, the first insulating film 3aAl2O3 and the second insulating film 3
It is desirable that the ratio of the thickness of Ta2O5 b be in the range of 1: 1 to 1:10.

In the above embodiment, the first insulating film 3a is made of Al2
The thickness of O3 is set in the range of 0.1 to 0.6 nm, and the thickness of Ta2O5 of the second insulating film 3b is set to 0.1 to 0.6 nm.
Although it is changed in the range of 5 to 12 nm, it has been confirmed that the same result can be obtained when the first insulating film 3a and the second insulating film 3b are replaced.

In the above embodiment, Al2O3 and Ta2
In this example, O5 is used as an insulating film, but zirconium oxide (ZrO2) or silicon oxide (SiO2) is used.
), Or titanium oxide (TiO), or hafnium oxide (HfO2), or niobium oxide (Nb)
O5) and use them (Al2O3 and Ta2O
The same effect can be obtained by using two of the above two types.

When these insulating films are formed, metal zirconium (Zr), silicon (Si), titanium (Ti), hafnium (Hf), or niobium (Nb) is used as a target, and argon (Ar) gas is used. Co-sputtering is performed in an atmosphere of a mixed gas with oxygen (O2) gas.

In a spin valve (SV) head composed of an antiferromagnetic layer, a pinning layer, an intermediate layer, and a free layer, a pair of insulating films are formed above and below the MR sensor, and both sides of the insulating films are formed. A pair of magnetic shield members are formed to eliminate a magnetic field other than the magnetic field generated by the reproduction signal. However, even for such a spin valve (SV) head, the insulating film is formed by the above-described means. , The same effect can be obtained.

[0047]

As described above, according to the magnetic head and the method of manufacturing the same of the present invention, when the insulating film is formed on and under the magnetoresistive sensor (MR sensor), alumina (Al2O3) or tantalum oxide is used. (Ta2 O5
) Or two kinds of oxides selected from zirconium oxide (ZrO2), silicon oxide (SiO2), titanium oxide (TiO), hafnium oxide (HfO2) or niobium oxide (NbO5),
By alternately laminating them at a predetermined thickness in a plurality of stages to make the entire thickness a predetermined thickness, it is possible to obtain an insulating film having excellent withstand voltage characteristics even if the entire thickness is reduced. There is an effect that an information storage device having a high recording density can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a lower insulating film of the embodiment of FIG.

FIG. 2 is a sectional view showing an embodiment of the magnetic head of the present invention.

3A and 3B are characteristic diagrams showing characteristics of a lower insulating film and an upper insulating film of the embodiment of FIG. 2 together with characteristics of a lower insulating film and an upper insulating film of a conventional magnetic head, and FIG. FIG. 4B is a characteristic diagram showing the dependence of the etching rate on the gas pressure at the time of sputtering, and FIG. 4B is a characteristic diagram showing the dependence of the withstand voltage characteristic on the gas pressure at the time of sputtering.

FIG. 4 is a characteristic diagram showing characteristics when the thickness of the first insulating film is fixed and the thickness of the second insulating film is changed in the lower insulating film and the upper insulating film of the embodiment of FIG. 2; (A) is a characteristic diagram showing a chemical etching rate with respect to an alkali developing solution, and (b) is a characteristic diagram showing a withstand voltage characteristic.

FIG. 5 is a characteristic diagram showing characteristics when the thicknesses of a first insulating film and a second insulating film are both changed in the lower insulating film and the upper insulating film of the embodiment of FIG. 2; 3 is a characteristic diagram showing a chemical etching rate with respect to an alkali developing solution, and FIG. 3B is a characteristic diagram showing a withstand voltage characteristic.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Lower shield film 3 Lower insulating film 3a First insulating film 3b Second insulating second film 4 Vertical bias film / electrode film 5 MR sensor 6 Upper insulating film 7 Upper shield film 8 Recording gap 9 Recording pole 10 Overcoat film 11 ~ 27 broken line

Claims (10)

[Claims] In a magnetic head having a pair of insulating films provided above and below a magnetoresistive sensor, the pair of insulating films are formed by alternately laminating two types of inorganic insulating materials each having a predetermined thickness in a plurality of stages. A magnetic head having a predetermined thickness. 2. The method according to claim 1, wherein the two kinds of inorganic insulating materials are two kinds of oxides selected from aluminum oxide, tantalum oxide, zirconium oxide, silicon oxide, titanium oxide, hafnium oxide, and niobium oxide. 2. The magnetic head according to claim 1, wherein: 3. The ratio of the thickness of each of the two types of inorganic insulating materials constituting the pair of insulating films is set to 1: 1 to 1:10.
3. The method according to claim 1, wherein
The magnetic head as described. 4. The magnet according to claim 1, wherein the thickness of the first insulating layer of the pair of insulating films is in a range of 0.2 to 0.5 nm. head. 5. A method of manufacturing a magnetic head in which a pair of insulating films are provided above and below a magnetoresistive sensor, wherein the pair of insulating films are formed by alternately laminating two types of inorganic insulating materials each having a predetermined thickness. A magnetic head having a predetermined thickness. 6. The method according to claim 1, wherein the two kinds of inorganic insulating materials are two kinds of oxides selected from aluminum oxide, tantalum oxide, zirconium oxide, silicon oxide, titanium oxide, hafnium oxide, and niobium oxide. The method for manufacturing a magnetic head according to claim 5. 7. An atmosphere of a mixed gas of argon gas and oxygen gas using two kinds of materials of metal aluminum, metal tantalum, metal zirconium, silicon, metal titanium, metal hafnium, or metal niobium as targets. 7. The method according to claim 6, wherein the two types of inorganic insulating materials are alternately laminated in a plurality of stages by performing co-sputtering. 8. The gas pressure at the time of sputtering is 0.3 to 0.8 P
8. The method for manufacturing a magnetic head according to claim 7, wherein a is set to a. 9. The method according to claim 5, wherein the ratio of the thicknesses of the two kinds of inorganic insulating materials forming the pair of insulating films is in a range of 1: 1 to 1:10. A method for manufacturing a magnetic head according to claim 7. 10. The method according to claim 5, wherein the thickness of the first insulating layer forming the pair of insulating films is in the range of 0.2 to 0.5 nm. A method for manufacturing a magnetic head according to claim 8.