JPH10255233A - Manufacture of magnetoresistive head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress decreasing of GMR film (giant magnetoresistive film) characteristic, etc., caused by unevenness of a substrate surface in the case that unevenness is formed inevitably on the surface of a magnetic shield layer, a magnetic yoke or the like which becomes a substrate of a GMR film of a shield-type GMR head or a yoke-type GMR head. SOLUTION: In a shield-type GMR head, smoothing processing is applied to, at least, one surface of a lower magnetic shield layer 23 and a lower magnetic gap film 24 to make a smoothed surface 24a from a GMR film substrate. And in a yoke-type GMR head, smoothing processing is applied to a main surface of a flat magnetic yoke. The surface smoothing processing is performed by low-angle ion milling processing, etchback processing using fluidity material, or smooth surface forming processing through inorganic insulating material such as SOG, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetoresistive head used in a magnetic recording / reproducing apparatus such as a magnetic disk drive.

[0002]

2. Description of the Related Art In recent years, the density of magnetic recording has been increasing. For example, in a hard disk drive (HDD), 1 Gbpsi / inch
High-density systems such as ² have been put into practical use,
Further, higher recording density is desired. In a read head in such a high recording density system, from the viewpoint of improving read sensitivity, a magnetic head (hereinafter, referred to as a magnetic head) utilizing a magnetoresistive effect in which the electric resistance of a certain magnetic thin film or a magnetic multilayer thin film is changed by an external magnetic field. , MR head). In the MR head, a change in an external magnetic field, that is, a change in a signal magnetic field recorded on a recording medium is converted into a resistance change and output.

Conventionally, a magnetoresistive film (MR film) has
Ferromagnetic materials exhibiting an anisotropic magnetoresistive effect (AMR) such as iFe alloys have been used, but the magnetoresistance change rate (MR change rate) of the AMR film is at most about 3%, and the size and capacity are increased The MR ratio is insufficient for the HDD used. Therefore, a giant magnetoresistive film (GMR film) capable of obtaining a large MR ratio has attracted attention, and a magnetic head (GMR head) using this film has been put into practical use. Especially,
Attention has been paid to a spin valve type GMR film having a sandwich film having a ferromagnetic layer / non-magnetic layer / ferromagnetic layer structure, and many GMR films having a multilayer structure have been developed.

FIG. 9 shows a configuration example of a conventional shield type MR head. An insulating layer 2 made of Al ₂ O ₃ or the like is formed on a main surface of a substrate 1 made of an Al ₂ O ₃ .TiC substrate (altic substrate) or the like constituting the head.
The Al ₂ O ₃ crystalline soft magnetic film and CoZrN such on the insulating layer 2, for example NiFe alloy film and FeAlSi alloy film
A lower magnetic shield layer 3 made of an amorphous soft magnetic film such as a b-based alloy film is formed.

[0005] On the lower magnetic shield layer 3, Al ₂ O ₃
An MR film 5 having a desired shape is formed via a lower magnetic gap film 4 made of a non-magnetic insulating material such as the above. This MR
A pair of electrodes (leads) 6 for supplying a sense current to the MR film 5 are connected to both upper ends of the film 5. Further, an upper magnetic shield layer 8 is formed with an upper magnetic gap film 7 interposed therebetween, and these constitute a shield type MR head 9.

In the conventional shield type MR head 9 described above, surface irregularities of each layer as described below are problematic. FIG. 10 is an enlarged model diagram showing a laminated portion up to the MR film 5 in FIG. As shown in FIG. 10, since the Al ₂ O ₃ .TiC substrate 1 constituting the head is a sintered body, it has large surface irregularities, for example, with a surface roughness R _max of about 0.8 μm. The large surface irregularities are transferred to the surface of the Al ₂ O ₃ insulating layer 2 to be formed by coating. Although the large irregularities on the surface of the Al ₂ O ₃ insulating layer 2 are removed by polishing or the like, it is inevitable that minute irregularities 10 having a surface roughness R _max of about 6 nm remain. Here, the surface irregularities in the present invention are measured by, for example, an atomic force microscope (AFM), a transmission electron microscope (TEM), a high-resolution scanning electron microscope (high-resolution SEM), or the like, for a predetermined range. Then, _Rmax is determined from the measurement range by a usual method.

Al ₂ O having such fine irregularities 10
_{(3) When the} lower magnetic shield layer 3 is formed on the insulating layer 2, abnormal growth occurs due to the fine irregularities 10 serving as nuclei. This abnormal growth is a core structure caused by surface irregularities, and the minute irregularities of the underlying layer are exaggerated to form the Al ₂ O ₃ insulating layer 2.
Surface irregularities 1 of the magnetic shield layer 3 below the surface irregularities 10
1 increases, it becomes 12nm, for example surface roughness R _max. At this time, when a crystalline soft magnetic material is selected for the lower magnetic shield layer 3, it is inevitable that the surface roughness is larger than the crystal grains. Further, the surface irregularities 11 ′ are naturally transferred to the lower magnetic gap film 4 formed on the lower magnetic shield layer 3.

When a GMR film such as a spin-valve film is formed as the MR film 5 on the base having the surface irregularities 11 'as described above, the thickness of each layer constituting the GMR film is 2 to 10
Since it is extremely thin, on the order of nm, there is a high possibility that the surface of the base on which the GMR film is formed, that is, the surface irregularities 11 'of the base cannot be uniformly covered. As described above, when a so-called poor cover registration state (indicated by reference numeral 12 in the figure) occurs, the GMR film having a multilayered structure has a step breakage, and the interlayer separation is impaired. This causes a problem such as a decrease in

On the other hand, in order to cope with an increase in recording density,
A yoke type MR head that can realize a contact recording / reproducing method is also being studied. This is the MR located inside the head
The signal magnetic field is guided to the element by a magnetic yoke having a magnetic gap film interposed on the medium facing surface side. As a conventional yoke type MR head, for example, a structure has been proposed in which an MR film is formed above a planar magnetic yoke so that the stripe direction extends over a back gap. In such a yoke type MR head, the surface unevenness of the magnetic yoke becomes a problem, and when a GMR film is applied, the same problem as the above-mentioned shield type MR head occurs.

Further, the yoke type MR head to which the plane type magnetic yoke is applied has a problem that the number of manufacturing steps is larger and the manufacturing cost is higher than the conventional thin film magnetic head. FIG. 11 and FIG. 12 show a manufacturing process of a conventional planar magnetic yoke.

That is, first, as shown in FIG. 11A, one soft magnetic layer 14 constituting a planar magnetic yoke is formed on a substrate 13. At this time, the film forming process, PEP
One process and one etching process are required. Next, as shown in FIG. 11B, the first soft magnetic layer 13 is formed.
The magnetic gap film 15 and the second soft magnetic layer 16 including the above are formed (1 film forming step). As shown in FIG. 11C, these surfaces are smoothed by etchback or the like (1).
After PEP, one etching step), as shown in FIG. 12A, a back gap 17 is formed by a PEP step and an etching step (1 PEP step, one etching step). After the insulating film 18 is formed on the back gap 17 formed by etching (FIG. 12B: one film forming step), the surface is smoothed as shown in FIG. 12C (1 PEP step, 1 etching process). Through these steps, the planar magnetic yoke 19 is obtained.

As described above, the conventional planar magnetic yoke 19
The manufacturing method of (1) requires three film forming steps, four PEP steps, and four etching steps, and thus increases the number of manufacturing steps.

[0013]

As described above, in the conventional shield type MR head, the surface irregularities on the substrate surface are amplified by the magnetic shield layer and the magnetic gap film, and
There is a problem that the presence of large surface irregularities on the underlayer surface of the film is unavoidable. If an MR film, particularly a GMR film having a laminated structure, is formed on a base having such surface irregularities, disconnection of the steps, poor interlayer separation, and the like are likely to occur.
This is a cause of deterioration in characteristics such as an R change rate. Yoke type MR
The same applies to the case of the head, and the same problem as the shield type MR head occurs due to the surface unevenness of the magnetic yoke. Furthermore, the yoke type MR head requires more manufacturing steps than conventional thin-film magnetic heads and the like, and increases the manufacturing cost.

The present invention has been made to address such a problem, and has been made in consideration of a magnetic shield layer and a magnetic yoke.
It is an object of the present invention to provide a method of manufacturing a magnetoresistive effect head capable of suppressing deterioration of characteristics of a GMR film even when irregularities are necessarily formed on a base surface of an MR film. It is another object of the present invention to provide a method of manufacturing a magnetoresistive head capable of suppressing an increase in manufacturing cost by reducing the number of manufacturing steps of a yoke type MR head.

[0015]

According to a first aspect of the present invention, there is provided a method of manufacturing a magnetoresistive head, comprising: a lower magnetic shield layer; and a lower magnetic gap film on the lower magnetic shield layer. A magnetoresistive element having a magnetic multilayer film of a ferromagnetic layer and a nonmagnetic layer, and an upper magnetic shield layer formed on the magnetoresistive element with an upper magnetic gap film interposed therebetween. The method of manufacturing a magnetoresistive head comprising the step of: performing a treatment on at least one surface of the lower magnetic shield layer and the lower magnetic gap film to smooth the surface.

In the smoothing step, for example,
As described in above, a step of ion-milling at least one surface of at least one of the lower magnetic shield layer and the lower magnetic gap film at a low angle while changing the ion irradiation angle on the surface of the lower magnetic shield layer. Alternatively, as described in claim 3, the smoothing step covers at least one surface of the lower magnetic shield layer and the lower magnetic gap film with a fluid material, and after curing the fluid material, A step of etching at least a part of at least one of the lower magnetic shield layer and the lower magnetic gap film through the cured fluid material may be performed. In addition, it is also possible to apply a surface smoothing step other than these.

In the above-described method of manufacturing a magnetoresistive head, at least one surface of the lower magnetic shield layer and the lower magnetic gap film is subjected to the above-described surface smoothing treatment. Therefore, even when irregularities are inevitably formed on the deposition surface of the lower magnetic shield layer, the magnetoresistive effect film composed of the magnetic multilayer film of the ferromagnetic layer and the nonmagnetic layer is smooth. An underlayer surface can be provided, and it is possible to suppress a decrease in characteristics of the magnetoresistive film.

According to another aspect of the present invention, there is provided a method of manufacturing a magnetoresistive head, comprising: a planar magnetic yoke having a magnetic gap on a medium facing surface side; In a method for manufacturing a magnetoresistive effect head including a magnetoresistive element portion formed on a surface and having a magnetic multilayer film of a ferromagnetic layer and a nonmagnetic layer, a process is performed on a main surface of the planar magnetic yoke. And a step of smoothing the main surface.

In this method of manufacturing a magnetoresistive effect head, even in the case where irregularities are inevitably formed on the surface of a planar magnetic yoke, a magnetic layer comprising a ferromagnetic layer and a nonmagnetic layer is used. A smooth underlayer surface can be provided for the resistance effect film. Accordingly, it is possible to suppress a decrease in the characteristics of the magnetoresistive film.

According to still another aspect of the present invention, there is provided a method of manufacturing a magnetoresistive head, comprising: a planar magnetic yoke comprising a pair of magnetic layers formed on a substrate; A magnetoresistive effect comprising: a magnetic gap interposed on the medium facing surface side of the yoke; and a magnetoresistive effect element formed on the planar magnetic yoke and having a magnetic multilayer film of a ferromagnetic layer and a nonmagnetic layer. In the method of manufacturing a head, a step of forming an island-shaped convex portion made of a nonmagnetic insulating material on the substrate, and one of the magnetic members constituting the planar magnetic yoke on the substrate having the island-shaped convex portion Forming a layer and processing at least the magnetic gap forming portion of the one magnetic layer; and forming the magnetic gap and the planar magnetic yoke on a substrate having the one magnetic layer. To form a magnetic layer, it is characterized by a step of smoothing the surface of the pair of magnetic layers.

In the above-described method of manufacturing a magnetoresistive head according to the present invention, the number of PEP steps and the number of etching steps for manufacturing a planar magnetic yoke can be reduced as compared with the conventional manufacturing steps. It is possible to suppress an increase in manufacturing cost in the yoke type magnetoresistive head.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an example of the configuration of a shield type GMR head manufactured by applying the method for manufacturing a magnetoresistive head of the present invention. FIG. 1 is a cross-sectional view as viewed from the medium facing surface, and the vertical direction is the scanning direction of the recording medium. This shield type GMR head is used, for example, as a reproducing head of a recording / reproducing integrated head.

In the figure, reference numeral 21 denotes an Al ₂ O ₃ insulating layer 2
2 is an Al ₂ O ₃ .TiC substrate having No. ₂ on its main surface. Although the surface of the Al ₂ O ₃ .TiC substrate 21 is polished, the fine irregularities 10 remain on the Al ₂ O ₃ insulating layer 22 as described above. On Al ₂ O ₃ insulating layer 22 having such fine irregularities 10, the crystalline soft magnetic film such as NiFe alloy film and FeAlSi alloy film and C
A lower magnetic shield layer 23 made of an amorphous soft magnetic film such as an oZrNb-based alloy film is formed.

The lower magnetic shield layer 23 is subjected to a surface treatment by, for example, low-angle ion milling in which the ion irradiation angle is changed, and the surface 23a is smoothed. Although the surface smoothing step will be described in detail later, in addition to the above-described low angle ion milling, for example, a flowable material is poured into a layer to be smoothed to fill fine irregularities, and the flowable material is cured and coated, Thereafter, a method of etching and smoothing a part of the layer to be smoothed through the hardened flowable material (etchback treatment using the flowable material) or the like can be applied. The layer to be subjected to the surface smoothing step may be a lower magnetic gap film 24 described later.

Further, the present invention is not limited to the above-described smoothing process by surface processing. For example, spin-on glass (SOG) is applied on the lower magnetic shield layer 23 or the lower magnetic gap film 24 and melt-sintered. By doing so, it is also possible to smooth the surfaces of the lower magnetic shield layer 23 and the lower magnetic gap film 24 by utilizing the surface smoothness of the glass. The glass layer is the lower magnetic gap film 2
Therefore, the lower magnetic shield layer 23 is preferably subjected to a surface smoothing step using glass.

On the lower magnetic shield layer 23 having the smoothed surface 23a, a lower magnetic gap film 24 made of a non-magnetic insulating material such as Al ₂ O ₃ is formed. The surface 24a of the lower magnetic gap film 24 also maintains a smooth state reflecting the surface smoothness of the lower magnetic shield layer 23. On the lower magnetic gap film 24 having such a smooth surface 24a, a GMR film 25 having a magnetic multilayer film of a ferromagnetic layer and a non-magnetic layer is formed in a desired shape.

Above both ends of the GMR film 25, a pair of electrodes (leads) 26 for supplying a sense current to the GMR film 25 and made of a conductive material such as Cu or a Cu alloy are formed. Here, the gap width between the pair of electrodes 26 defines the track width. A CoPt for applying a bias magnetic field to the GMR film 25 is provided below both ends in the width direction of the GMR film 25.
A pair of hard magnetic films 27 made of an alloy or the like are formed.
These constitute the GMR element section 28.

An upper magnetic gap film 29 made of a non-magnetic insulating material similar to the lower magnetic gap film 24 is formed on the above-mentioned GMR element portion 28, and further thereon, the lower magnetic shield layer 23 is formed. An upper magnetic shield layer 30 made of the same soft magnetic material as described above is formed. With these layers, the shield type GMR head 31 of this embodiment is used.
Is configured. The shield type GMR head 31
Is used as the reproducing head of the integrated recording / reproducing head, the upper magnetic shield layer 30 also serves as the lower recording magnetic pole of the recording head.

In the above-mentioned shield type GMR head 31, the GMR film 25 sandwiched between the lower magnetic shield layer 23 and the upper magnetic shield layer 30 detects a signal magnetic flux from the recording medium. The lower magnetic shield layer 23 and the upper magnetic shield layer 30 absorb magnetic flux other than the magnetic flux of the bit being detected, and increase the resolution between reproduced bits.
The thickness direction of the lower magnetic gap film 24 and the upper magnetic gap film 29 corresponds to the reproduction bit length, and the gap between the pair of electrodes 26 through which the sense current flows corresponds to the track width.

Here, the GMR film 25 is, for example, a ferromagnetic layer /
FIG. 2 shows an example of the spin valve GMR film 25 having a sandwich film having a nonmagnetic layer / ferromagnetic layer structure. Spin valve GMR film 25 shown in FIG.
Are sequentially formed on the lower magnetic gap film 24 having the smooth surface 24a, and the CoZrNb magnetic underlayer 251 (1
0 nm) / NiFe magnetic underlayer 252 (2 nm) / CoFe ferromagnetic layer (magnetic free layer) 253 (3 nm) / Cu nonmagnetic layer 25
4 (3 nm) / CoFe ferromagnetic layer (magnetized pinned layer) 255 (2n
m) / IrMn antiferromagnetic layer 256 (8 nm) / Ta protective film 2
It has a laminated film having a 57 (20 nm) structure, and this laminated film is processed into a desired shape. In addition, on the lower magnetic gap film 24, a pair of hard magnetic films 27 that have been processed into a desired shape in advance are formed.

Next, the above-mentioned shield type GMR head 3
Regarding one example of the manufacturing process of 1 and the evaluation result,
This will be described with reference to FIGS. The manufacturing process described here corresponds to an embodiment of the method of manufacturing a magnetoresistive head according to the present invention. First, the Al ₂ O ₃ insulating layer 2
Al ₂ O ₃ .TiC substrate having a thickness of 1.2 mm (diameter 1.2 mm, diameter
76.2 mm) 21 were prepared. Although the main surface of the Al ₂ O ₃ .TiC substrate 21 was polished, the fine irregularities 10 remained on the Al ₂ O ₃ insulating layer 22. in addition,
1.6 μm thick Co ₈₇ Zr ₅ as the lower magnetic shield layer
The amorphous soft magnetic film 23 'of nb ₈ composition was formed by sputtering (Figure 3 (a)). Note that a sputtering method was used in all of the following film formation steps.

At this time, since the amorphous soft magnetic film 23 'is used for the lower magnetic shield layer, the influence of the minute unevenness 10 on the surface of the Al ₂ O ₃ insulating layer 22 is not so much affected. surface roughness of 'the film formation surface 23a' of the film 23 was 8nm in R _max. Such an amorphous soft magnetic film 2
A surface smoothing process described below was performed on the film forming surface 23a 'of 3'.

[0034] That is, FIG. 3 (b), the ion milling device on the substrate holder 32 New Komeito rotation possible (not shown), Al ₂ forming the amorphous soft magnetic film 23 '
Install the O ₃ with Al ₂ O ₃ · TiC substrate 21, after evacuating the inside of the apparatus in a vacuum, Ar gas was introduced into the ion gun, the acceleration voltage 500V, Ar ions 33 of the ion current density 1 mA / cm ²
Thus, the film forming surface 23a 'of the amorphous soft magnetic film 23' was milled.

Here, the angle θ at which the amorphous soft magnetic film 23 ′ is irradiated with the Ar ions 33 is 5 to 20 °, and the irradiation angle is scanned within this range. As described above, by irradiating the Ar ions 33 at a low angle and scanning the irradiation angle, minute irregularities can be milled quickly while large irregularities can be milled quickly. That is, a smooth surface can be obtained in a short time. At this time, if the irradiation angle θ of the Ar ions 33 exceeds 20 °, the milling may proceed to increase the concavities and convexities.
Is preferably 20 ° or less. on the other hand,
If the irradiation angle θ is less than 5 °, a sufficient milling effect cannot be obtained.

Further, when an ion milling method as described above, be smoothed with even a scratch or the like is large scratches generated in the polishing step of the Al ₂ Omicron with ₃ Al ₂ O ₃ · TiC substrate 21 Can be. After performing such ion milling, the amorphous soft magnetic film 23 '
When the surface roughness was measured, R _max was 3 nm, which was less than half that before processing.

By the above-described ion milling process, the surface of the amorphous soft magnetic film 23 'is smoothed and slightly thinned, and the surface roughness _Rmax is 3 nm and the thickness is 1.5.
A μm lower magnetic shield layer 23 was obtained. Thus, the lower magnetic shield layer 23 whose surface 23a is smoothed
As shown in FIG. 3C, the lower magnetic gap film 2
As No. 4, an Al ₂ O ₃ film having a thickness of 100 nm was laminated. The surface 24a of the lower magnetic gap film 24 also has a surface roughness R.
_{The max} was 4 nm, which was excellent in smoothness. Thus, a smooth underlayer of the GMR film 25 was obtained.

Next, a Co ₈₀ Pt ₂₀ film having a thickness of 20 nm is formed on the lower magnetic gap film 24 having the smooth surface 24a, and is processed into a desired shape by a PΕΡ step and an ion milling step. Then, a pair of hard magnetic films 27 were formed. Subsequently, each layer of the spin valve GMR film 25 shown in detail in FIG. 2 was sequentially formed, and processed into a desired shape through a similar processing step (FIG. 4A). Furthermore, spin valve GMR
A Ta (10 nm) / Cu (100 nm) / Ta (10 nm) laminated film is formed on the film 25, and is processed into a desired shape through a similar processing step to form a pair of electrodes 26 (FIG. 4). (B)).

After the above steps, an Al ₂ O ₃ film having a thickness of 100 nm as the upper magnetic gap film 29 and a Co ₈₇ Ζr ₅ Nb ₈ amorphous soft magnetic film having a thickness of 1.5 μm as the upper magnetic shield layer 30. Are sequentially formed, and the shield type MR head 3
1 was obtained.

According to the above-described manufacturing process of the shield type MR head 31, the film forming surface 23a 'of the amorphous soft magnetic film 23' serving as the lower magnetic shield layer 23 is subjected to a low-angle ion milling treatment, and Surface 23a of side magnetic shield layer 23
Since the are smooth, whereas R _max in the film forming surface 23a 'under the influence of surface irregularities of the substrate 21 was 8 nm, greatly enhance the R _max 3 nm and the surface smoothness after processing Was possible. Then, by forming the spin valve GMR film 25 on such a smooth underlayer, it is possible to greatly suppress the occurrence of step disconnection, interlayer separation failure, and the like due to the influence of surface irregularities. Therefore, it is possible to stably obtain the characteristics such as the MR change rate of the spin valve GMR film 25.

As described above, the surface smoothing step in the present invention may be performed on the magnetic gap film 24, and a specific processing method such as an etch-back processing using a fluid material is applied. can do. An embodiment in which the magnetic gap film 24 is subjected to a surface smoothing process by an etch-back process using a fluid material will be described below with reference to FIG.

First, the same Al ₂ O ₃ as in the above embodiment was used.
On the main surface of the attached Al ₂ O ₃ .TiC substrate 21, a Ni ₈₀ Fe ₂₀ crystalline soft magnetic film having a thickness of 2 μm was formed as the lower magnetic shield layer 23. As shown in FIG. 5A, an Al ₂ O ₃ film having a thickness of 200 nm is formed on the lower magnetic shield layer 23 as a lower magnetic gap film, including a reduced portion etched in a later smoothing step. 24 'was laminated.

At this time, the surface 24 of the Al ₂ O ₃ film 24 ′
a ′ had a surface roughness R _max of 15 nm. Next, this A
Al ₂ O ₃ with Al ₂ O ₃ formed with l ₂ O ₃ film 24 ′
After rotating the TiC substrate 21 with a spinner and applying a low-molecular-weight liquid photoresist having a styrene-equivalent molecular weight of 2500 as a flowable material, which easily covers minute irregularities, on the surface of the Al ₂ O ₃ film 24 ′, gradually from 423 to 493 K. Then, a heating baking treatment was performed to cure the resist, thereby forming a resist coating layer 34 having a thickness of 0.5 μm (FIG. 5B).

At this time, Al ₂ O ₃ .TiC with Al ₂ O ₃
Scratch such a large scratch generated in the polishing process of the substrate 21, Al ₂ O ₃ by the resist coating layer 34
The film 24 'was covered with the fine irregularities, and a smooth surface 34a was obtained as shown in FIG. 5B. It should be noted that a similar smooth surface can be obtained by using an ultraviolet curable acrylic resin instead of the photoresist and curing by ultraviolet irradiation.

Next, in order to set the etching selectivity between the photoresist and Al ₂ O ₃ to 1, CF ₄ gas and CHF
By reactive ion etching using ₃ mixed gas of the gas, and sequentially etching the resist coating layer 34 and the Al ₂ O ₃ film 24 '. When the Al ₂ O ₃ film 24 ′ is etched to a predetermined thickness of 100 nm as the lower magnetic gap film 24, fine irregularities and scratches are obtained as shown in FIG.
As shown in FIG. 7, the lower magnetic gap film 24 having a smooth surface 24a was obtained.

The lower magnetic gap film 2 which has been subjected to a smoothing step by an etch-back process using the above-mentioned fluid material.
The surface roughness of No. 4 was R _max 5 nm, and the surface smoothness was greatly improved. On the smooth underlayer of the GMR film 25 thus obtained, the spin valve GMR film 25 (GMR element section), the upper magnetic gap film 29 and the upper magnetic shield layer 30 are sequentially formed in the same manner as in the above-described embodiment. Forming
A shield type GMR head 31 was obtained.

According to the manufacturing process of the shield type MR head 31 described above, Al ₂ O to be the lower magnetic gap film 24 is formed.
_{3 The} film forming surface 23a 'of the film 24' is etched back via the resist coating layer 34 for filling the minute unevenness to smooth the surface 24a of the lower magnetic gap film 24. Under the influence, R _max was 15 nm on the film forming surface 24 a ′, whereas R _max 5
It was possible to greatly improve the surface smoothness in nm. Then, by forming the spin valve GMR film 25 on such a smooth underlayer, it is possible to greatly suppress the occurrence of step disconnection, interlayer separation failure, and the like due to the influence of surface irregularities. Therefore, it is possible to stably obtain the characteristics such as the MR change rate of the spin valve GMR film 25.

Next, an embodiment in which the method of manufacturing a magnetoresistive head of the present invention is applied to a yoke type GMR head will be described.

FIG. 6 is a perspective view showing a main part of the yoke type GMR head manufactured in this embodiment. In the figure, reference numeral 21 denotes Al with Al ₂ O ₃ similar to that of the above-described embodiment.
₂ O ₃ .TiC substrate. This Al ₂ O ₃ with Al ₂ O
_{3. On} the main surface of the TiC substrate 21, fine irregularities (not shown) remain as described above. Such Al ₂ O
_{3. A} planar magnetic yoke 43 comprising a pair of magnetic cores (magnetic layers) 41 and 42 on an Al ₂ O ₃ .TiC substrate 21 with
Are formed.

The planar magnetic yoke 43 is formed such that its main surface 43a is substantially parallel to the surface of the substrate 21. On the medium facing surface S side of the planar magnetic yoke 43,
A magnetic gap 44 is interposed between the pair of magnetic cores 41 and 42. That is, a pair of magnetic cores 41 and 42 disposed on the medium facing surface S with the magnetic gap 44 interposed therebetween.
Is exposed only.

The main surface 4 of the above-mentioned flat magnetic yoke 43
3a, a spin valve G similar to the above-described embodiment is provided.
An MR film 25 is formed. Therefore, the planar magnetic yoke 4
3 has an effect on the characteristics of the spin valve GMR film 25. In this embodiment, the main surface 43a of the planar magnetic yoke 43 has a non-magnetic insulating layer 4 for smoothing the surface.
5 are formed.

The structure of the non-magnetic insulating layer 45 for smoothing the surface was as follows. First, an insulating Si film for improving the adhesion to the magnetic layers 41 and 42 and the magnetic gap 44 and the wettability of the SOG is formed, and SOG whose surface is smoothed by melt-sintering is formed thereon. Al ₂ O 3 for moisture absorption of SOG and prevention of over-etching in the next step
An O ₃ film was formed. This insulating Si film / SOG / Al ₂
The laminated film of the O ₃ film was used as the non-magnetic insulating layer 45 for smoothing the surface.

[0053] The surface roughness of the smooth surface for the non-magnetic insulating layer 45 described above was 5nm at R _max. The spin valve GMR film 25 is formed on such a smooth underlayer. The spin valve GMR film 25 is formed at a position inside the head receding from the medium facing surface S, and a pair of electrodes 26 is formed at both ends thereof.

The non-magnetic insulating layer 45 is partially removed on the rear side of the flat magnetic yoke 43 when viewed from the medium facing surface S, that is, on the back gap 46, and a pair of magnetic cores 41 is
A back core 47 that is magnetically coupled to 42 is formed, and these form a recording magnetic loop. A recording coil 48 is wound in a plane so as to cross the recording magnetic loop. FIG. 6 shows a yoke type GMR head used as a recording / reproducing integrated magnetic head. The recording medium is scanned in a direction crossing the magnetic cores 41 and 42. That is, the track width is equivalent to the thickness of the magnetic cores 41 and 42, and the recording and reproducing bit length is the gap 44.
Corresponds to the width of

According to the above-described yoke type MR head and its manufacturing process, even if the main surface 43a of the planar magnetic yoke 43 has irregularities due to the influence of the surface irregularities of the substrate 21, the surface is smoothed thereon. Since the non-magnetic insulating layer 45 is provided for smoothing, the surface smoothness of the base of the spin valve GMR film 25 can be greatly improved. Then, by forming the spin valve GMR film 25 on such a smooth underlayer, it is possible to greatly suppress the occurrence of step disconnection, interlayer separation failure, and the like due to the influence of surface irregularities. Therefore, it is possible to stably obtain the characteristics such as the MR change rate of the spin valve GMR film 25.

The main surface 43 of the planar magnetic yoke 43
For the smoothing of a, it is possible to use an organic insulating material such as a resist material or a polyimide resin, but these organic insulating materials have water absorption, and this water absorption has an adverse effect on the characteristics of the GMR head. Therefore, it is preferable to use the above-mentioned inorganic insulating material such as SOG. If the non-magnetic insulating layer for smoothing the surface has a water absorbing property, it is inevitable that water used for cleaning in the head manufacturing process and moisture in the air invade, and the MR element is deteriorated in the head manufacturing stage, In addition, the electrical withstand voltage also decreases. Further, the completed head is subjected to a heat treatment in a magnetic field, and the heated moisture is sealed as vapor once absorbed moisture, and the pressure causes the film to peel off. In the worst case, the head is damaged. Destroyed.

Further, in the above-mentioned surface smoothing step of the flat type magnetic yoke, it is possible to apply the low-angle ion milling processing or the etch-back processing using a fluid material shown in the above-described embodiment. is there.

The flat magnetic yoke used in the above-described embodiment is manufactured as follows. The manufacturing process of the planar magnetic yoke will be described with reference to FIGS.

First, as shown in FIG.
Island-shaped convex portions 51 made of a non-magnetic insulating material such as SiO _x are formed on the main surface of the main surface of the main surface so as to substantially correspond to the shape of the back gap. At this time, a film forming step, a PEP step, and an etching step are required once each. In the PEP step and the etching step, the SiO _x layer 52 is also left around so as to define the yoke formation position. On these, a soft magnetic film 53 serving as a first magnetic core is formed (FIG. 7B: one film forming step), and at least a magnetic gap forming portion 53a of the soft magnetic film 53 is processed (FIG. 7
(C): 1 PEP step, 1 etching step).

Next, as shown in FIG. 8A, a nonmagnetic insulating film 54 serving as a magnetic gap film and a soft magnetic film 55 serving as a second magnetic core are formed (one film forming step). The surfaces of the magnetic cores are smoothed by etch back or the like (1 PEP step, 1 etching step), as shown in FIG. A planar magnetic yoke 43 composed of 41 (53) and 42 (55) is obtained.

In the manufacturing process of the above-described embodiment, the planar magnetic yoke 43 is obtained by three film forming processes, three PEP processes, and three etching processes. The number of manufacturing steps can be reduced as compared with a manufacturing method that requires four PEP steps and four etching steps. Therefore, the manufacturing cost of the yoke type MR head can be reduced.

By forming the non-magnetic insulating layer 45 for smoothing the surface on the flat magnetic yoke 43 manufactured in the above embodiment, it can be used for the yoke type MR head of the above embodiment. Also, by applying low angle ion milling or the like to the final smoothing step, it can be used as it is for a yoke type MR head.

[0063]

As described above, according to the method of manufacturing a magnetoresistive head of the present invention, even if irregularities are necessarily formed on the underlying surface of a GMR film such as a magnetic shield layer and a magnetic yoke, Since the smoothness of the underlayer surface can be greatly improved by the smoothing step, it is possible to suppress the deterioration of the characteristics of the GMR film and the like. According to another method of manufacturing a magnetoresistive head according to the present invention, a yoke-type magnetoresistive head can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 shows a shield type GM to which the manufacturing method of the present invention is applied.
FIG. 3 is a cross-sectional view illustrating a schematic structure of an embodiment of an R head.

FIG. 2 is a cross-sectional view showing one structural example of a spin valve GMR film used in the shield type GMR head shown in FIG.

FIG. 3 is a sectional view showing a main part of a manufacturing process according to the embodiment of the shield type GMR head shown in FIG. 1;

4 is a shield type GM following the manufacturing process shown in FIG.
It is sectional drawing which shows the manufacturing process of an R head.

FIG. 5 is a cross-sectional view showing a main part of a manufacturing process according to another embodiment of the shield type GMR head shown in FIG. 1;

FIG. 6 is a yoke type GMR to which the manufacturing method of the present invention is applied.
FIG. 2 is a perspective view illustrating a schematic structure of an embodiment of a head.

FIG. 7 is a cross-sectional view showing a main part of a manufacturing process of a planar magnetic yoke used in the yoke type GMR head shown in FIG.

8 is a cross-sectional view showing a manufacturing step of the planar magnetic yoke subsequent to the manufacturing step shown in FIG. 7;

FIG. 9 is a sectional view showing a schematic structure of a conventional shield type MR head.

FIG. 10 is an enlarged model diagram showing a main part of the shield type GMR head shown in FIG. 9;

FIG. 11 is a cross-sectional view illustrating a main part of a manufacturing process of a conventional planar magnetic yoke.

FIG. 12 is a cross-sectional view showing a manufacturing step of the conventional planar magnetic yoke following FIG. 11;

[Explanation of symbols]

 23 Lower magnetic shield layer 24 Lower magnetic gap film 23a, 24a Smooth surface 25 Spin valve GMR film 29 Upper magnetic gap film 30 Upper magnetic shield layer 43 Planar magnetism Yoke 44 ... magnetic gap

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahisa Yoshikawa 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Shiba-Kawasaki Office (72) Inventor Masaji Sabashi 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Shibakawasaki Office

Claims (5)

[Claims] 1. A magnetoresistive element portion comprising: a lower magnetic shield layer; and a magnetic multilayer film of a ferromagnetic layer and a nonmagnetic layer formed on the lower magnetic shield layer via a lower magnetic gap film. And a method of manufacturing a magnetoresistive effect head comprising: an upper magnetic shield layer formed on the magnetoresistive element portion via an upper magnetic gap film; wherein the lower magnetic shield layer and the lower magnetic gap film A method for manufacturing a magnetoresistive head, comprising a step of performing a treatment on at least one surface to smooth the surface. 2. The method of manufacturing a magnetoresistive head according to claim 1, wherein said smoothing step includes irradiating at least one surface of said lower magnetic shield layer and said lower magnetic gap film with ions. A method for manufacturing a magnetoresistive effect head, comprising a step of performing ion milling at a low angle while changing the angle. 3. The method of manufacturing a magnetoresistive head according to claim 1, wherein in the smoothing step, at least one surface of the lower magnetic shield layer and the lower magnetic gap film is covered with a fluid material. A step of, after curing the fluid material, etching at least a part of at least one of the lower magnetic shield layer and the lower magnetic gap film through the cured fluid material. Manufacturing method of effect head. 4. A magnetic device comprising: a planar magnetic yoke having a magnetic gap on a medium facing surface side; and a magnetic multilayer film formed on a main surface of the planar magnetic yoke and composed of a ferromagnetic layer and a nonmagnetic layer. A method of manufacturing a magnetoresistive head comprising a resistance effect element portion, comprising a step of performing a treatment on a main surface of the planar magnetic yoke to smooth the main surface. Manufacturing method. 5. A planar magnetic yoke comprising a pair of magnetic layers formed on a substrate, a magnetic gap interposed on the medium facing surface side of the planar magnetic yoke, and formed on the planar magnetic yoke. And a method of manufacturing a magnetoresistive head including a magnetoresistive element having a magnetic multilayer film of a ferromagnetic layer and a nonmagnetic layer, comprising: forming an island-shaped convex portion made of a nonmagnetic insulating material on the substrate; Forming, forming one magnetic layer constituting the planar magnetic yoke on the substrate having the island-shaped convex portions, and processing at least the magnetic gap forming portion of the one magnetic layer. Forming the magnetic gap and the other magnetic layer constituting the planar magnetic yoke on the substrate having the one magnetic layer, and smoothing the surfaces of the pair of magnetic layers. When A method for manufacturing a magnetoresistive effect head, comprising: