JPH05274626A - Mr head - Google Patents

Abstract

PURPOSE:To prevent the generation of noise by a change in magnetic characteristics and the drop of an output voltage by forming an MR element in such a manner that the element hardly receives the deformation by the internal stress of insulating films enclosing the element. CONSTITUTION:The lower insulating film 34, the MR element 14 and the upper insulating film 36 are laminated and formed on a substrate 10. The internal stress of the lower substrate 34 is balanced by the deformation of the substrate 10 at the point of the time when this insulating film is formed and, therefore, even if the MR element 14 is laminated thereon, the deformation that the MR element 14 receives from the internal stress of the lower insulating film 34 is small. Since a space 38 is formed atop the MR element 14, the internal stress of the upper insulating film 36 is not directly transmitted to the MR element 14 and its deformation is small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to MR (magnetoresis).
This is a magnetic head that suppresses changes in magnetic characteristics due to internal stress of an insulating film surrounding the MR element.

[0002]

2. Description of the Related Art An MR head is a magnetic head for reproducing recorded information by detecting a magnetic field generated from a magnetic pole of a magnetic recording medium by using an MR element, and has an advantage that a track density can be improved as compared with a thin film head. For example, it is expected to be used as a reproducing head for a hard disk.

An outline of the MR head is shown in FIGS. 2 (a) and 2 (b). (A) is a read-only head, in which an MR element 14 and magnetic shields 16 and 18 in front of and behind the MR element 14 are provided in an insulating film 12 formed at a rear end portion of a substrate 10 to form an MR head 19. The tip of 14 is made to face the recording surface 20 of the magnetic recording medium (for example, hard disk), and the recorded information is read. The structure of the read end surface portion of the MR head 19 is shown in FIG.

FIG. 2B shows a composite type head in which a recording induction type thin film head 22 is laminated on the insulating film 12 of FIG. The thin film head 22 is the lower core 24.
The gap layer 26 is formed on the insulating layer 27, and the thin film coil 28 is arranged in the insulating layer 27. Further, an upper core 30 is formed on the insulating layer 27, and a protective film 32 is entirely covered on the upper core 30.

[0005]

The MR head 19 shown in FIG.
In, the insulating film 12 is formed by sputtering Al ₂ O _3, for example, and is usually 10 ⁸ to 10 ⁹ dym / cm 2.
^{It has} an internal stress (residual stress) of the order of ² . On the other hand, M
Since the R element 14 is a magnetic substance, it has magnetostriction, and even in the case of permalloy, it has a magnetostriction constant of about 10 ⁻⁶ . Therefore, the MR element 14 has a problem that the magnetic characteristics are affected by the internal stress of the insulating film 12 and the characteristics as an element such as output reduction and noise increase deteriorate. This is because the magnetic anisotropy is affected by the internal stress of the insulating film 12, and the MR element 1
It is considered that this is because the anisotropy of No. 4 in the longitudinal direction is reduced. As a result, it is considered that the output is reduced even when the magnetic field to be detected enters at right angles to the longitudinal direction of the MR element 14.
Regarding noise, it is considered that the magnetic anisotropy dispersion increases due to stress and Barkhausen noise increases.

In order to prevent the magnetic characteristics of the MR element 14 from being affected by the stress of the insulating film 12, it is conceivable to reduce the magnetostriction constant of the MR element 14, but the magnetostriction constant is the material of the MR element 14. Heavily dependent on composition (especially
In the case of permalloy), the value becomes large if it deviates from the ideal composition. From an industrial point of view, it is difficult to strictly control this composition, and it is desired that the magnetic characteristics are not affected even if the composition deviates slightly.

The present invention has been made in view of the above points, and even if a magnetoresistive material having a large magnetostriction constant is used, the magnetic characteristics are not so much influenced by the internal stress of the insulating film, and the output is lowered. The present invention intends to provide an MR head in which deterioration of characteristics such as increase in noise and noise is prevented.

[0008]

According to the present invention, a substrate, a lower insulating film formed on the substrate, an MR element formed on the lower insulating film, and a space on the MR element are provided. It is formed by integrally laminating the formed upper insulating film.

[0009]

According to the present invention, when the lower insulating film is formed on the substrate, the internal stress of the lower insulating film is balanced by the deformation of the substrate. Therefore, the MR element is formed on this. However, the MR element is hardly affected by the internal stress (that is, deformed) from the lower insulating film. However,
If the upper insulating film is further formed in close contact with the upper surface of the MR element in this state, the internal stress of the upper insulating film and the entire deformation from the underlying substrate to the MR element are balanced, so that the MR element Will be directly affected (deformed) by the internal stress of the upper insulating film. Therefore, in the present invention, the upper insulating film is formed above the MR element with a space therebetween so that the MR element is not directly affected (deformed) by the internal stress of the upper insulating layer. And by this, MR
Even if the magnetostriction constant of the element is large to some extent, the internal stress of the insulating film does not significantly affect the magnetic characteristics, so that deterioration of characteristics such as output reduction and noise increase can be prevented.

[0010]

EXAMPLE An example in which the present invention is applied to an MR head for a hard disk will be described below. FIG. 1 is an embodiment of an MR head of the present invention, in which (a) is a side sectional view showing a state in which an MR head 33 is levitated over a recording surface 20 of a magnetic recording medium (hard disk) for reading. (B) CC arrow view), (b) is a BB arrow view of (a). In the MR head 33, the lower insulating film 34 is provided on the substrate 10, and the magnetic shield 18 is housed in the lower insulating film 34. The MR element 14 is disposed on the lower insulating film 34. Conductors (not shown) are connected to both ends of the MR element 14 as electrodes. An upper insulating film 36 is provided on the lower insulating film 34 except for the MR element 14.
The magnetic shield 16 is housed therein. Therefore, on the MR element 14, the upper insulating film 3 is separated by the space 38.
6, the MR element 14 and the upper insulating film 36 are substantially in non-contact with each other. The tips of the MR element 14 and the magnetic shields 16 and 18 are exposed at the read surface 40. Although the tip of the space 38 is open, it can be closed if dust or the like is a problem. Further, the thin film head 22 may be laminated on the MR head 33 as shown in FIG. 2B to form an MR / thin film composite head.

According to the above structure, at the time when the lower insulating film 34 is formed on the substrate 10, the internal stress of the lower insulating film 34 is in a balanced state due to the deformation of the substrate. Therefore, even if the MR element 14 is formed on this,
The MR element 14 is less affected by the internal stress of the lower insulating film 34. If the upper insulating film 36 is formed in close contact with the MR element 14 in this state as it is, the internal stress of the upper insulating film 36 and the entire deformation of the substrate 10 to the MR element 14 thereunder are balanced. The MR element 14 is directly affected by the internal stress of the upper insulating film 36. However, since the upper insulating film 36 is formed above the MR element 14 with the space 38 therebetween, the MR element 14 is not directly affected by the internal stress of the upper insulating film 36. Therefore, even if the magnetostriction constant of the MR element 14 is large to a certain extent, the internal characteristics of the insulating films 34 and 36 do not significantly affect the magnetic characteristics, so that deterioration in characteristics such as output reduction and noise increase can be prevented.

FIGS. 4 and 5 show an embodiment of the manufacturing process of the MR head of the present invention. The processes (1) to (1) are shown.
4) will be described. Note that, in this step, as in the manufacturing process of the thin film head, M is formed on one substrate 10 (wafer).
A large number of R heads are formed at one time and then cut into individual MR heads. FIGS. 4 and 5 show this process of forming one MR head.

(1) Lower insulating film is formed halfway on the substrate 10 of Al ₂ O ₃ —TiC or the like, and a dielectric insulating layer of Al ₂ O ₃ (SiO ₂ or the like) is used as the lower insulating film 34 by high frequency sputtering. The film is formed to a thickness of 10 μm. The film forming rate is 200 angstrom / minute.

(2) Deposition of lower magnetic shield Ni ₈₁ Fe ₁₉ (Ni: 81%, F by DC sputtering method)
e: 19%) A film 18 'is formed to a thickness of 1 μm. The argon pressure during film formation is 5 × 10 ⁻³ Torr, and the film formation rate is 200 Å / min.

(3) Processing of lower magnetic shield The formed Ni ₈₁ Fe ₉₁ film is processed into 30 μm (width) × 30 μm (depth) by a photoetching method to form the lower magnetic shield 18.

(4) Forming the rest of the lower insulating film Al ₂ O ₃ is formed at a film forming rate of 200 Å / min and a bias of −100 V to 0.5 μm, and the lower insulating film 34 is formed.
To complete. The internal stress generated inside the lower insulating film 34 by the film formation is balanced by the deformation of the substrate 10.

The internal stress itself of the lower insulating film 34 can be relaxed by performing an appropriate heat treatment after forming the lower insulating film 34.

(5) Deposition of MR element After the surface of the lower magnetic film 34 is polished and smoothed as needed, Ti is used as a shunt film of 400 Å and Co ₉₄ Zr ₆ film is used as a soft film bias film of 400. Angstrom, Ni ₈₁ Fe as magnetoresistive film
_The MR element film 14 'is formed by sequentially forming ₁₉ films in the order of 300 angstroms. The film formation is performed by a direct current sputtering method, the argon pressure at that time is 5 × 10 ⁻³ Torr, and the film formation rates are 300, 200, and 200 Å / min, respectively. At the time of forming the MR element film 14 ', the lower insulating film 3 is formed.
Since the internal stress of No. 4 is already balanced with the deformation of the substrate 10 as described above, the MR element 14 does not need to be much affected by the internal stress of the lower insulating film 34. In particular, if the lower insulating film 34 is formed and then heat-treated, its influence can be made extremely small.

(6) Processing of MR element The formed MR element film 14 'is 20 μm (width) × 5 μm
The MR element 14 is manufactured by processing to (depth). As a processing method, an ordinary photo-etching method using a positive resist is used. That is, first, a positive resist is applied on the entire surface of the MR element film 14 ', the area outside the above range is removed by development, and the exposed MR element film 14' is removed by etching (ion milling) to form the MR element 14.

(7) Film formation of Au conductor After applying a negative resist on the entire surface, the resist is developed and removed by a size required as a conductor (electrode) of the MR element 14. After the Au film is formed there, the resist is removed with a stripping solution, leaving only the conductor portions bonded on the magnetoresistive film, and the Au conductors 42 and 44 are formed. The Au conductors 42 and 44 have a width of 10 μm, a thickness of 2000 Å, and a read gap 46 of 5 μm.

(8) Formation of Space The upper insulating film 36 is partially formed while forming the space 38 by the steps (8) to (12). First, positive resist 4
8 is applied over the entire surface and is slightly larger than the MR element 14 21 μm
The size of (width) × 6 μm (depth) is left, and the others are removed by development.

(9) As the upper insulating film 36, Al ₂ O is formed by a high frequency sputtering method.
₃ is formed on the entire surface. The film forming rate is 200 angstrom / minute. -100V to fill the step of the resist
Bias is applied. The film thickness is 0.5 μm.

(10) A negative resist (not shown) is applied to the entire surface. After application M
1 μm (width) on the negative resist above the R element 14
Develop and remove 1 μm (depth) holes. A hole 50 is formed in the upper insulating film 36 by etching (ion milling) through this hole.

(11) The entire substrate is immersed in a stripping solution to remove the negative resist remaining on the upper insulating film 36 and the positive resist 48 remaining on the MR element 14 to form a space 38 on the MR element 14. Form. The stripping solution remaining in the space 38 is replaced with a volatile organic solvent, and then the organic solvent is removed by heating or the like.

(12) The hole 50 is filled with Al ₂ O ₃ by the same high frequency sputtering film forming method. The film forming speed at this time is 200 angstrom / min.
The bias is -100V. After filling the holes 50, the entire film-forming surface is polished and smoothed if necessary. The polishing agent is an aqueous solution in which alumina particles (average particle size 1 μm) are suspended
6. Polishing speed is 0.5 μm / min, and polishing is performed until the average roughness becomes 100 angstroms or less.

(13) Film formation and processing of upper magnetic shield A Ni ₈₁ Fe ₁₉ film of 1 μm is formed by DC sputtering. The argon pressure during film formation is 5 × 10 ⁻³ Torr, and the film formation rate is 200 Å / min. Ni ₈₁ deposited
Fe ₉₁ film 30μm (width) x by photo-etching method
It is processed to 30 μm (depth) and used as the upper magnetic shield 16.

(14) Forming Remaining Upper Insulating Film A film of Al ₂ O ₃ is formed at a film forming rate of 200 Å / min at a bias of −100 V to a thickness of 20 μm to complete the upper insulating film 36. In this state, the internal stress of the upper insulating film 36 acts so as to be balanced by the deformation of all the layers therebelow, but there is a space 38 on the MR element 14 and the upper insulating film 3
Since 6 is not in direct contact with the MR element 14, the stress of the upper insulating film 36 is not directly transmitted to the MR element 14. Therefore, the magnetic characteristics of the MR element 14 are not directly affected by the upper insulating film 36, and the deterioration of characteristics such as output reduction and noise increase is prevented. In particular, the upper insulating film 36 is
Since the MR element is affected by the characteristics depending on the temperature, it is generally impossible to perform the heat treatment for relaxing the stress of the lower insulating film 36 (see step (5)). Therefore, the effect of providing the space 38 is great.

The MR head 33 is completed through the above steps.
When using the MR / thin film composite head as shown in FIG. 2,
Further, by continuing the conventional thin film head manufacturing process by lithography, M
A thin film head can be laminated on the R head 33. After that, the substrate 10 is cut and separated into individual magnetic heads, the cut substrate 10 is formed into a slider shape, the air bearing surface is polished, and the MR / thin film composite head for hard disk (recording with a thin film head, MR head Playback) is completed.

FIG. 6 shows an observed waveform of the reproduction output when the same recording portion of the same recording medium is traced by the MR head 33 manufactured by the steps of FIGS. 4 and 5 and the conventional MR head 19 of FIG. It is a thing. (A) Conventional MR head 19
Then, the MR element 14 has the insulating film 12 adhered to the entire surface thereof.
It can be seen that the magnetic anisotropy is affected by the internal stress of 1 and the noise 54 (Barkhausen noise) is generated as a result. On the other hand, it can be seen that the MR head according to the present invention of (b) does not generate such noise and the output level is higher than that of (a).

The MR head of the present invention is not limited to the case where the substrate, the lower insulating film, the MR element, the space, and the upper insulating film are directly laminated, and other layers may be interposed between them if necessary. You can also

Further, the space is not formed on the entire upper surface of the MR element, but it is possible to obtain a certain effect only by forming the space on a part thereof.

The present invention can also be applied to MR heads other than magnetic heads for hard disks.

[0033]

As described above, according to the present invention, by forming the upper insulating film with a space above the MR element, the MR element is not directly affected by the internal stress of the upper insulating layer. As a result, even if the magnetostriction constant of the MR element is large to some extent, it is possible to prevent the magnetic characteristics from being greatly affected by the internal stress of the insulating film, and to prevent the deterioration of characteristics such as output reduction and noise increase.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of an MR head.

FIG. 3 is a diagram showing a state in which a conventional MR head is viewed from the direction of arrow A in FIG.

FIG. 4 is a diagram showing a first half portion of an embodiment of the manufacturing process of the MR head of the present invention.

FIG. 5 is a diagram showing a latter half of one embodiment of the manufacturing process of the MR head of the present invention, which is subsequent to FIG. 4;

6 is a diagram showing an observed waveform of a reproduction output when the same recording portion of the same recording medium is traced by the MR head 33 manufactured by the steps of FIGS. 4 and 5 and the conventional MR head 19 of FIG. ..

[Explanation of symbols]

 10 Substrate 14 MR Element 33 MR Head 34 Lower Insulating Film 36 Upper Insulating Film 38 Space

Claims (1)

[Claims] 1. A substrate, a lower insulating film formed on the substrate, an MR element formed on the lower insulating film, and an upper insulating film formed on the MR element with a space therebetween. An MR head that is integrally laminated.