JP3102505B2 - Method for manufacturing soft magnetic multilayer plating film, soft magnetic multilayer plating film, and magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer plating film having soft magnetism, a method for manufacturing the same, and a magnetic head having the multilayer plating film as a magnetic pole.

[0002]

2. Description of the Related Art A magnetic pole of a thin-film magnetic head and a magnetic film formed in a gap of a metal-in-gap (MIG) type magnetic head are required to have a high saturation magnetic flux density, and further have a high magnetic permeability and a low magnetic permeability. Excellent soft magnetic properties such as magnetic force are required.

[0003] A 50% Co-Fe alloy (permendur) has the highest saturation magnetic flux density Bs of 2.4 T in the alloy and has an anisotropy constant K ₁ of zero, but has a saturated magnetostriction constant λ.
Since s is as large as 10 ^-5 , high magnetic permeability cannot be obtained.

[0004] Under such circumstances, in "Magnetic Characteristics of Fe / Co and Fe / CoFe Multilayer Films" (MR87-36, pp. 7-12), an Fe layer and a Co layer are laminated and further heat-treated. To form a CoFe layer at the interface and to stack an Fe layer and a CoFe layer. This proposal proposes that although Fe and Co have negative magnetostriction, the CoFe alloy layer has positive magnetostriction in most composition ranges. Therefore, zero magnetostriction is realized by stacking these layers. In this proposal, Fe
The layer, the Co layer and the CoFe layer are formed by an ion beam sputtering method.

Japanese Patent Application Laid-Open No. 61-97906 discloses that a 50 wt% Co · 50 wt% Fe alloy and a 81 wt% Ni ·
An artificial lattice magnetic thin film in which 19 wt% Fe alloys are alternately laminated at 30 A each, and the saturation magnetic flux density is 17 kG, 5 MHz.
Has a magnetic permeability of 1500. This artificial lattice magnetic thin film is formed by the EB evaporation method.

[0006]

As described above, a multilayer film is generally formed by a vapor phase plating method such as a vapor deposition method. However, since a vapor phase plating method requires a vacuum, the equipment cost is high and mass production is required. There is no sex. However, Fe / Co and Fe
/ CoFe and CoFe / NiFe multilayer films are difficult to form by liquid phase plating.

The present invention has been made in view of the above circumstances, and a soft magnetic multilayer film having excellent soft magnetic properties, particularly a high saturation magnetic flux density, has been prepared by using a liquid phase plating method which has low equipment cost and high mass productivity. It is another object of the present invention to provide a magnetic head capable of significantly increasing the recording density by using such a soft magnetic multilayer film as a magnetic pole.

[0008]

This and other objects are achieved by the present invention which is defined below as (1) to (10).

(1) Substantially Co, Fe and M (where M is Pd, Cu, Pt, Au, Ag, Ir, R
h or Ru. ), And a method of manufacturing a soft magnetic multilayer plating film in which an intermediate thin film having a higher M content than the soft magnetic thin film is alternately laminated. The plating bath used for forming the intermediate thin film is such that the total content of Co ion and Fe ion = 0.05 to 10 mol / l, Co ion / (Co ion + Fe ion) = 0.4 to 0.8 (molar ratio) ), Content of M ion = 10 of the total weight of Co ion and Fe ion
A method for producing a soft magnetic multilayer plating film, wherein the concentration is from 1000 to 1000 ppm.

(2) The soft magnetic multilayer plating film according to (1), wherein the soft magnetic thin film is formed by electroplating, and the intermediate thin film is formed by electroplating, displacement plating or electroless plating. Production method.

(3) The method according to (1), wherein the soft magnetic thin film is formed by an electroless plating method, and the intermediate thin film is formed by an electroplating method.

(4) The method for producing a soft magnetic multilayer plating film according to any one of the above (1) to (3), wherein a heat treatment is performed after forming the soft magnetic multilayer plating film.

(5) Formula (Co _x Fe _1-x ) _{1- y My} (where M is Pd, Cu, Pt, A
u, Ag, Ir, Rh or Ru, and x and y represent atomic ratios, 0.4 ≦ x ≦ 0.8, y ≦ 0.
It is one. A) a soft magnetic thin film having a composition represented by:
A soft magnetic multilayer plating film characterized in that intermediate thin films having a higher M content than the soft magnetic thin film are alternately laminated.

(6) The soft magnetic multilayer plating film according to the above (5), wherein the saturation magnetic flux density is 20 kG or more.

(7) The above (5 or (6)), wherein M is Pd and the saturation magnetostriction constant λs is + 3 × 10 ⁻⁶ or less.
2. The soft magnetic multilayer plating film according to item 1.

(8) The thickness of the soft magnetic thin film is 5000
A or less, and the thickness of the intermediate thin film is 2500 A or less. The soft magnetic multilayer plating film according to any one of the above (5) to (7).

(9) The soft magnetic multilayer plating according to any one of the above (5) to (8) produced by the method for producing a soft magnetic multilayer plating film according to any one of the above (1) to (4). film.

(10) A magnetic head comprising the soft magnetic multilayer plating film according to any of (5) to (9) as a magnetic pole.

[0019]

According to the present invention, a soft magnetic thin film containing Co--Fe as a main component and having a high saturation magnetic flux density and M (where M is Pd, C
u, Pt, Au, Ag, Ir, Rh or Ru. ) And an intermediate thin film having a main component of) are alternately laminated by a liquid phase plating method to form a soft magnetic multilayer plating film.

In the present invention, the soft magnetic thin film is formed by electroplating, and the intermediate thin film is formed by electroplating, displacement plating or electroless plating. The soft magnetic thin film and the intermediate thin film are usually formed continuously in the plating bath containing Co, Fe and M.

When the soft magnetic thin film and the intermediate thin film are formed by the electroplating method, the deposition potential of Co and the deposition potential of Fe are more negative than the deposition potential of M, that is, are lower. Co, Fe and M are deposited on the cathode by applying a potential more negative than the deposition potential to the cathode to form a soft magnetic thin film, and an intermediate thin film is formed by applying the potential at which only M is deposited to the cathode. I do.

When the intermediate thin film is formed by the displacement plating method, the voltage application is interrupted after the soft magnetic thin film is formed by the electroplating method. Since Co and Fe have a greater ionization tendency than M, Co and Fe
And Fe are eluted into the plating bath, and instead, M is deposited on the soft magnetic thin film to form an intermediate thin film.

When the intermediate thin film is formed by the electroless plating method, if a predetermined voltage is applied during the electroless plating, Co, Fe and M precipitate, and a soft magnetic thin film can be formed.

In the present invention, the soft magnetic thin film can be formed by electroless plating, and the intermediate thin film can be formed by electroplating. In this case, if a predetermined voltage is applied during the electroless plating, M precipitates and an intermediate thin film can be formed.

In these liquid phase plating methods, by using the plating bath having the above-described composition, a high quality soft magnetic multilayer plating film having a high saturation magnetic flux density and a low coercive force can be obtained.

When a film is formed by the liquid phase plating method, the crystal grain size becomes smaller as the film becomes thinner. Therefore, the crystal grain size of the laminated film can be made smaller than that of a single layer film having the same thickness. as a result,
Dispersion of crystal magnetic anisotropy in the soft magnetic thin film is suppressed, and excellent soft magnetic properties such as low coercive force and high magnetic permeability can be obtained.

When a multilayer plating film is formed by the liquid phase plating method as described above, each layer is not completely separated, and a transition region whose composition changes in the thickness direction is formed near the boundary between two adjacent layers. However, in the present invention, such a transition region is considered as a part of the intermediate thin film.

The intermediate thin film is provided for cutting off the crystal grain growth of the soft magnetic thin film. Since the crystal grain size of the soft magnetic thin film can be made smaller as the transition region is thinner, it is generally preferable to select plating conditions that make the transition region thinner.

However, when Pd is used as M, C
Since the transition region containing o, Fe and Pd has an effect of shifting the magnetostriction of the soft magnetic multilayer plating film to the negative side,
By intentionally providing the transition region, the magnetostriction of the entire soft magnetic multilayer plating film can be significantly reduced. Co-F
In the single-layer film of e-Pd, the magnetostriction decreases as the Pd content increases, but the coercive force Hc increases.
However, according to the present invention, a soft magnetic thin film containing little Pd and having a low Hc and an intermediate thin film having a transition region having a high Pd content and a low magnetostriction are laminated to form a multilayer film, thereby achieving a low Hc and low Hc. Magnetostriction is realized.

The thickness of the transition region can be controlled by plating conditions, heat treatment after plating, and the like.

The intermediate thin film is a nonmagnetic material substantially made of M except for the transition region.

The soft magnetic multilayer plating film of the present invention thus manufactured is suitable for a magnetic pole of a thin film magnetic head, a MIG type magnetic head, a perpendicular magnetic head, and also a thin film transformer.

In Japanese Patent Publication No. 45-5122,
A multilayer thin film having a magnetic layer containing Ni, Fe and 30% or less Cu, and a nonmagnetic layer containing Ni, Fe and 30% or more Cu is disclosed. This multilayer thin film does not use Co-Fe, but is formed by a liquid phase plating method. However, its operation and effect are different from those of the present invention. According to the description of the publication, during application of a pulse voltage, a Cu-rich non-magnetic layer is plated first, and then a magnetic layer containing less Cu is plated.

However, if the non-magnetic layer and the magnetic layer are formed in this way, the interface between the non-magnetic layer and the magnetic layer becomes unclear, and the effect of the present invention, ie, the grain refinement effect cannot be obtained. . Further, since the content of Cu ions in the plating bath is large, the Cu content of the magnetic layer is increased, and a high saturation magnetic flux density cannot be obtained.

[0035]

[Specific Configuration] Hereinafter, a specific configuration of the present invention will be described in detail.

<Soft Magnetic Multilayer Plating Film> The soft magnetic multilayer plating film of the present invention (hereinafter, simply referred to as a multilayer plating film) comprises a soft magnetic thin film and an intermediate thin film each formed by a liquid phase plating method on a substrate. It has a stacked configuration.

The soft magnetic thin film has a composition represented by the formula _{(Co x Fe 1-x)} 1-y M y. However, in the above equation,
M is Pd, Cu, Pt, Au, Ag, Ir, Rh or Ru. X and y represent the atomic ratio, and
4 ≦ x ≦ 0.8, preferably 0.4 ≦ x ≦ 0.6, y ≦
0.1, preferably y ≦ 0.05. If x is outside the above range, the saturation magnetic flux density will be insufficient. If y exceeds the above range, the coercive force tends to be high, and good soft magnetic properties tend not to be obtained. When forming a soft magnetic thin film,
Since M ions precipitate in addition to Co ions and Fe ions, y> 0.

The intermediate thin film has a higher M content than the soft magnetic thin film. As described above, the region where the transition from the soft magnetic thin film to the intermediate thin film is a transition region where Co and Fe gradually decrease and M gradually increases, and the region where the intermediate thin film transitions to the soft magnetic thin film is where Co and Fe transition. This is a transition region in which M gradually increases and gradually decreases. When Pd is used as M, the magnetostriction in the transition region is smaller than the magnetostriction of the soft magnetic thin film. Therefore, by forming the transition region, the magnetostriction of the soft magnetic multilayer plating film can be reduced. When a transition region containing Pd is formed, the saturation magnetostriction constant λs of the soft magnetic multilayer plating film is +3
× 10 ⁻⁶ or less, particularly about 0 to + 3 × 10 ⁻⁶ . In this case, the transition region is preferably thicker, and the entire intermediate thin film may be the transition region.

On the other hand, when an element other than Pd is used as M, the transition region is preferably thin in order to reduce the crystal grain size of the soft magnetic thin film.

According to the present invention, the crystal grain size of the soft magnetic thin film can be set to about 50 to 200 A.

The intermediate thin film is a non-magnetic material substantially made of M except for the transition region.

The soft magnetic thin film and the intermediate thin film include Co, F
In addition to e and M, B, S, C and the like may be contained in an amount of 5 atomic% or less of the whole.

The thickness of the soft magnetic thin film is preferably 5000 A or less, particularly preferably 1000 A or less. If the thickness of the soft magnetic thin film exceeds the above range, the crystal grains become too large.

The thickness of the intermediate thin film is preferably 2500 A or less, particularly preferably 250 A or less. It is preferable that the thickness of the intermediate thin film is 1/20 to 1/5 of the thickness of the soft magnetic thin film. When the thickness of the intermediate thin film exceeds the above range,
Bs of the multilayer plating film becomes insufficient.

There is no particular lower limit on the thickness of the soft magnetic thin film and the thickness of the intermediate thin film. However, if the thickness is 20 A or more, it is easy to keep the film thickness uniform and the film quality is good.

The thickness of each thin film can be measured by a transmission electron microscope or the like, and its crystal structure or the like can be confirmed by X-ray diffraction, high-speed reflection electron beam diffraction or the like.

The multilayer plating film of the present invention usually has excellent magnetic properties such as a saturation magnetic flux density of 20 kG or more, a coercive force of 5 Oe or less and a magnetic permeability at 5 MHz of 1000 or more.

In the multilayer plating film of the present invention, the number of laminated thin films is not particularly limited, and the thickness of each thin film is selected from the preferable range described above, and the total thickness of the multilayer plating film is determined by the purpose of use. May be appropriately determined according to the conditions.

An antioxidant film such as silicon nitride or silicon oxide may be provided on the surface of the uppermost thin film, and a metal conductive layer for leading an electrode may be provided depending on the application. Good.

The material of the substrate on which the soft magnetic thin film and the intermediate thin film are formed is not particularly limited, and may be appropriately selected according to the application and the like. Examples thereof include magnesium oxide, glass, silicon single crystal, and strontium titanate. Crystal, gallium-
An arsenic single crystal or a metal single crystal such as copper, iron, or cobalt is particularly preferable, but a normal conductive metal or a ceramic such as AlTiC (Al ₂ O ₃ —TiC) can also be used. Also, the dimensions of the base may be appropriately determined according to the application.

If the substrate does not have conductivity, a base film may be provided between the base and the thin film if necessary. As the base film, a thin film of Au, Cu, Ag, Pd, Permalloy, Pt, or the like is preferable, and the thickness thereof is preferably about 1000A or less, particularly preferably 200A or less. The base film can be formed by a wet method such as an electroless plating method, but is preferably formed by a vacuum film forming method such as an MBE method.

By providing such a base film, the growth of the plating thin film can be made more uniform, and conductivity can be imparted to the substrate.

<Production Method> Hereinafter, a method for producing the multilayer plating film of the present invention will be described.

The substrate on which the plating film is to be formed is provided with an undercoat film as described above, if necessary. Next, the base is washed with acid to activate the surface, and further washed with pure water to form a plating film. The pickling and the water washing are preferably performed at room temperature.

Electroplating of soft magnetic thin film and intermediate thin film
When both the soft magnetic thin film and the intermediate thin film are formed by the electroplating method, a potential lower than the deposition potential of Co and the deposition potential of Fe is applied to the substrate to form a soft magnetic thin film.
Then, an intermediate thin film is formed by applying a potential nobler than these deposition potentials and lower than the deposition potential of M to the substrate.

The transition region existing near the soft magnetic thin film of the intermediate thin film is formed when the potential of the substrate is changed to the base side or the noble side before and after the formation of the soft magnetic thin film. The thickness of the transition region and the concentration gradient of each element in the transition region can be adjusted by controlling the potential change pattern.

When both the soft magnetic thin film and the intermediate thin film are formed by the electroplating method, two kinds of potentials are usually applied alternately. However, after the soft magnetic thin film is formed, the potential is shifted to the noble side. Alternatively, a pattern may be used in which the potential of the substrate on which the soft magnetic thin film is formed is once more noble than the deposition potential of M, and then lower than the deposition potential of M. This allows Co
And the precipitation of Fe can be stopped quickly, and the transition region described above can be prevented from being formed unnecessarily thick.

The soft magnetic thin film is electroplated to form an intermediate thin film.
Method of forming a film by displacement plating The displacement plating method uses a plating bath containing ions of a metal that is more noble than the metal of the object to be plated, and elutes the object to be plated into the plating bath. Is deposited on an object to be plated.

In the present invention, the soft magnetic thin film is the object to be plated. When the lowermost thin film closest to the substrate is formed by the displacement plating method, the base film or the base film provided between the substrate and the lowermost layer is formed. It becomes an object to be plated. Specifically, using a plating bath containing Co ions, Fe ions, and M ions, Co, Fe, and M are deposited by an electroplating method to form a soft magnetic thin film. Alone precipitate to form an intermediate thin film. In this case, the soft magnetic thin film and the intermediate thin film can be alternately laminated only by applying the voltage intermittently, and there is no need to perform complicated potential control.

It is to be noted that, if necessary, an electroplating bath and a displacement plating bath may be independently provided to perform each plating.

In the embodiment using the displacement plating method, Co and Fe in the soft magnetic thin film are replaced with M in the plating bath to reduce the thickness of the soft magnetic thin film.
It is preferable to form the film to a thickness that allows for the reduced thickness.

When the intermediate thin film is formed by the displacement plating method, the thickness of the transition region can be generally reduced as compared with the case of using the electroplating method.

The soft magnetic thin film is formed on the intermediate thin film by electroplating.
Method of Forming Film by Electroless Plating Method During the formation of the intermediate thin film by depositing M by the electroless plating method, if a potential lower than the deposition potential of Co and the deposition potential of Fe is applied to the substrate, Co, Fe And M precipitate, forming a soft magnetic thin film.

The soft magnetic thin film is formed by an electroless plating method.
A method of forming a thin film by electroplating During the formation of a soft magnetic thin film by depositing Co, Fe and M by electroless plating, the deposition potential of Co and the deposition potential of Fe are more noble than the deposition potential of M, and When a low potential is applied to the substrate, M precipitates and an intermediate thin film is formed.

The plating bath used in each of the above methods contains Co ions, Fe ions and M ions. The content of each ion is expressed as the total content of Co ions and Fe ions = 0.
05-10 mol / l, Co ion / (Co ion + Fe ion) = 0.4-0.8 (molar ratio), M ion content = 10-1000 of the total weight of Co ion and Fe ion
ppm, preferably, the total content of Co ion and Fe ion = 0.1 to 4 mol / l, Co ion / (Co ion + Fe ion) = 0.4 to 0.6 (molar ratio), content of M ion Amount = 10 of the total weight of Co ions and Fe ions
500 ppm.

If the content of Co ions or the content of Fe ions exceeds the above range, the amount of these ions pumped out becomes too large, and the viscosity becomes too high to make stirring difficult. On the other hand, if the content is less than the above range, the film forming rate is insufficient.

The ratio between Co ions and Fe ions is
It is determined according to the desired composition of the soft magnetic thin film.

When the soft magnetic thin film is formed by the electroplating method, the rate of mixing of M into the soft magnetic thin film is suppressed by utilizing diffusion control. The amount of M mixed into the magnetic thin film is too large. However, when the content of M ions is less than the above range, the film formation rate of the intermediate thin film becomes insufficient.

When the intermediate thin film is formed by the electroless plating method, the precipitation reduction potential of M differs depending on the pH, the type of the reducing agent, the temperature, and the like. However, in order to use the diffusion control, the current of M is 1/20 of the current of Co and Fe.
It is preferable to select various conditions so as to be as follows.

The Co ions and Fe ions in the plating bath were Co (II) and Fe (II), respectively.
Exists as an ion.

In the plating bath, in addition to these ions, a conductive aid such as sodium chloride, a substitution improver such as ammonium persulfate and thallous nitrate, a pH adjuster such as boric acid,
Various auxiliary components such as a surfactant may be contained as necessary.

When the electroless plating method is used, various reducing agents such as hypophosphite, dimethylamine borane, formalin and thiourea are contained.

<High-Speed Plating Method> When the displacement plating method is used in the present invention, it is preferable to use the high-speed plating method. The high-speed plating method is a method generally used in the electroplating method, in which a plating bath is forcibly flowed in the vicinity of a cathode (object to be plated), thereby reducing the thickness of a diffusion layer near the surface of the cathode, and forming a coating on the surface of the cathode. This is a method for sufficiently supplying metal ions.

Since the concentration of M ions in the vicinity of the substrate becomes non-uniform due to the precipitation of M and the plating film tends to grow in a cluster shape, when the intermediate thin film is formed thin, the film may not be formed in a film shape. In the high-speed plating method, since the plating bath near the substrate is forced to flow, the metal ion concentration in the vicinity of the substrate hardly becomes uneven. Further, since the concentration of M ions in the vicinity of the base does not decrease,
The formation speed of the intermediate thin film is improved.

As the high-speed plating method, it is preferable to perform plating while forcing the plating solution relative to the substrate, or to perform plating while rubbing the surface of the plating thin film. The method of flowing is preferred. It is also preferable to use these methods in combination. The flow rate of the plating solution with respect to the substrate when these methods are used is 0.5 m / s or more, particularly 5 to 30 m / s.
Preferably, it is 0 m / s. By causing the plating solution to flow relatively to the substrate in such a range, the formation speed of the intermediate thin film is significantly improved, and the uniformity of the intermediate thin film is significantly improved.

More specifically, high-speed plating methods include a parallel flow method, a jet flow method, an ultrasonic irradiation method, an electrode vibration method, a high-speed rotation method of an electrode, and a method of rubbing an electrode surface during plating. Preferably, it is used.

In the parallel flow method, the distance between the anode and the cathode (substrate) is kept small, and the plating solution in the gap flows at a high speed.
When applying the parallel flow method to the multilayer plating film of the present invention,
It is preferable that the flow speed of the plating solution is about 0.5 m / s or more.

In the jet flow method, a plating solution is jetted from a nozzle toward a substrate in a jet flow. The nozzle and the substrate may be in the plating bath or outside the plating bath. When applying the jet flow method to the formation of the multilayer plating film of the present invention, since a flow close to a laminar flow is desirable,
Instead of placing the nozzle near the center of the base, place the nozzle near the end of the base or near the holder of the base,
It is preferable to spray a plating solution from that position to form a high-speed, constant-direction flow on the substrate.

In the ultrasonic irradiation method, a substrate is irradiated with ultrasonic waves,
This is to stir the plating solution near the substrate. When the ultrasonic irradiation method is applied to the formation of the multilayer plating film of the present invention, the frequency is preferably 500 MHz or more.

In the electrode vibration method, plating is performed while the substrate is vibrated. When applied to the formation of a multilayer plating film of the present invention,
The amplitude of the substrate is about 0.05 to 1 mm, and the frequency is 100 Hz to
Preferably, the frequency is about 10 kHz.

The high-speed electrode rotation method performs plating while rotating the substrate, and is useful for substrates having an axially symmetric shape such as a disk or a cylinder.

The method of rubbing the electrode surface during plating involves plating the substrate while rubbing the substrate with an insulating substance.

The high-speed plating method in the electroplating method is described on pages 184 to 189 of “Plating Book” (published by Nikkan Kogyo Shimbun, edited by the Electroplating Research Group).

Further, such a high-speed plating method can be used for forming an intermediate thin film or a soft magnetic thin film by an electroplating method.
You may apply as needed.

<Heat Treatment> In the present invention, the above-described transition region is formed in the intermediate thin film near the boundary with the soft magnetic thin film. It is possible to control the thickness of the transition region and the concentration gradient of each element by controlling the plating conditions. Are diffused into each other, so that the thickness of the transition region can be increased.

When Pd is used as M, the magnetostriction of the multilayer plating film changes depending on the thickness of the transition region. If the magnetostriction does not fall within the required range, the magnetostriction should be adjusted by performing heat treatment. Can be. The conditions for this heat treatment are not particularly limited. That is, since the heat treatment conditions are different depending on the configuration of the transition region formed by the plating method, it may be experimentally determined so as to obtain the required magnetostriction value. 0.5-3
It is preferable to set the time to about time.

It is to be noted that, when forming the multilayer film, a condition where the transition region is thinned is selected to form fine crystal grains, and a heat treatment is performed under such a condition that crystal grain growth does not occur, thereby expanding the transition region. A multilayer plating film having excellent characteristics can be obtained.

<Applications> The multilayer plating film of the present invention is suitable for various applications in which excellent soft magnetic properties such as high magnetic permeability and low coercive force are required and high saturation magnetic flux density is required. It is suitable for a pole layer of a thin film magnetic head.

The thin-film magnetic head has a magnetic pole layer, a gap layer, a coil layer and the like formed on a substrate by a thin-film forming method such as a vapor phase plating method or a liquid phase plating method. Such a thin film magnetic head is generally used as a floating magnetic head for a hard disk.

The structure of the thin-film magnetic head to which the present invention is applied is not limited. For example, the present invention can be applied to various types of structures, including a floating type thin-film magnetic head having a structure as shown in FIG. .

In the thin-film magnetic head 10 shown in FIG. 1, an insulating layer 31, a lower magnetic pole layer 41, a gap layer 50, an insulating layer 33, a coil layer 60, an insulating layer 35, an upper magnetic pole layer 45, It has a layer 70 in sequence and is used for a magnetic disk for in-plane recording.

The coil layer 60 is usually made of a metal such as Al and Cu.

The substrate 20 is usually made of ceramics such as Mn-Zn ferrite and Al ₂ O ₃ —TiC.

The magnetic pole is usually formed on the lower magnetic pole layer 4 as shown in the figure.
1 and the upper magnetic pole layer 45, and the multilayer plating film of the present invention is used for these magnetic pole layers.

A gap layer 50 is formed between the lower pole layer 41 and the upper pole layer 45. The gap layer 50 is made of Al
_{It is} composed of a non-magnetic material such as ₂ O ₃ and SiO ₂ .

The coil layer 60 is of a so-called spiral type, and the lower and upper magnetic pole layers 41 and 45 are spirally formed.
The insulating layers 33 and 35 are provided between the coil layer 60 and the lower and upper magnetic pole layers 41 and 45. An insulating layer 31 is provided between the lower magnetic pole layer 41 and the base 20. As a material of the insulating layer, for example, SiO ₂ , glass, Al ₂ O ₃ or the like is used.

On the upper pole layer 45, a protective layer 70 is provided. The protective layer is made of, for example, Al ₂ O ₃ or the like. Various resin coating layers and the like are laminated on the protective layer as needed.

The manufacturing process of such a thin film magnetic head is as follows.
Usually, it is composed of thin film preparation and pattern formation. The lower and upper magnetic pole layers 41 and 45 are formed by the various liquid phase plating methods described above. In this case, a conductive base film as described above may be provided as necessary. Further, each layer other than the magnetic pole layer may be formed by using a vapor phase film forming method such as a vacuum evaporation method or a sputtering method. However, depending on the material, a liquid phase plating method may be used. The pattern formation of each layer of the thin-film magnetic head is usually performed by selective etching, selective deposition, or the like.

Such a thin film magnetic head is used in combination with a conventionally known assembly such as an arm.

The multilayer plating film of the present invention is suitable not only for such a thin-film magnetic head for in-plane recording but also for a perpendicular magnetic head for a magnetic recording medium having a perpendicular magnetization magnetic layer such as Co-Cr. When the multilayer plating film of the present invention is applied to a perpendicular magnetic head, it is usually used as a main magnetic pole.

In addition to these, the multilayer plating film of the present invention can be applied to a MIG type magnetic head. MI
A G-type magnetic head is a magnetic head in which a soft magnetic film having a higher saturation magnetic flux density Bs than a core of the head is provided in the vicinity of a gap of a normal ring-type magnetic head. As the magnetic film, a high Bs material such as Sendust is used. In the MIG type magnetic head, the soft magnetic film acts as a magnetic pole. The multilayer plating film of the present invention is applied to such a soft magnetic film of a MIG type magnetic head.

Further, in addition to these various magnetic heads, the multilayer plating film of the present invention is suitable for various applications requiring excellent soft magnetic properties, such as a thin film transformer, a magnetoresistive magnetic head, a magnetic field sensor, and the like. is there.

[0103]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

Example 1 A 50 × 50 × 1 mm magnesium oxide substrate was coated on a surface of C with a thickness of 100 A by MBE.
u underlayer was formed. The surface of the underlayer is 0.1N at room temperature.
After washing with -HCl for 20 seconds, further washing with pure water for 20 seconds.

Next, a soft magnetic thin film and an intermediate thin film were laminated on the base film by electroplating using the following plating bath.

(Plating bath composition) Cobalt sulfate and iron sulfate: The total content was 0.2 mol / l in terms of Co ion and Fe ion, respectively. The ratio of Co ions in the total is shown in the plating bath composition column of Table 1 below.

Boric acid: 0.5 mol / l Lithium chloride: 0.5 mol / l Sodium lauryl sulfate: 0.01 g / l

Palladium chloride and copper sulfate: P
of the content when converted to d ions and Cu ions,
The ratio to the total weight of Co ions and Fe ions is shown in the plating bath composition column of Table 1 below.

The temperature of the plating bath is 40 ° C., the pH of the plating bath
Was 2.7, and Pt was used for the anode.

When a plating bath containing Pd ions is used, a voltage is applied to the substrate in a cycle of 20 V (1 second) → 2.5 V (5 seconds), and this cycle is repeated 45 times to obtain a multilayer plating film. And The application of the voltage was stopped for 0.5 seconds after the application of the voltage of 20 V, the potential of the cathode surface was adjusted, and then the voltage of 2.5 V was applied.

Further, when a plating bath containing Cu ions was used, the substrate was charged from 20 V (1 second) to 1.7 V (10 V).
) Cycle, and this cycle was repeated 45 times to obtain a multilayer plated film. The voltage application time was when the Cu ion concentration was 150 ppm. In other cases, the voltage application time was changed according to the Cu ion concentration and the thickness of the intermediate thin film. After applying a voltage of 20 V,
After applying a voltage of 1.7V for 0.5 seconds, + 1.7V
Is applied.

The ratio between the Co content and the Fe content in the soft magnetic thin film of the multilayer plating film sample thus formed is almost the same as the ratio between Co ions and Fe ions in the plating bath. The M content was 2 atomic% or less. Also,
The intermediate thin film had M as a main component and Co and Fe.

Table 1 shows the thickness of the soft magnetic thin film, the thickness of the intermediate thin film, and the crystal grain size of the soft magnetic thin film. Sample No. 1-5 is a comparative sample using a plating bath containing no Cu ions.

The thickness of each thin film was measured by a transmission electron microscope, the composition of each thin film was measured by plasma emission analysis (ICP), and the crystal grain size of the soft magnetic thin film was determined by X-ray diffraction using Cu-Kα ray. Was calculated by

The magnetic properties of these samples were measured as described below.

(Saturation magnetic flux density Bs) Measured by VSM.

(Coercive force Hc) Measured by a BH tracer.

(Permeability μ) Measured by using a figure 8 coil.

(Saturation Magnetostriction Constant λs) A sample was placed in a rotating magnetic field in the film plane, and the warpage of the sample was detected and measured by a synchronous rectification method using a laser. The results are shown in Table 1 below.

[0120]

[Table 1]

Example 2 On the substrate used in Example 1,
The soft magnetic thin film was formed by electroplating, and the intermediate thin film was formed by displacement plating.

The composition of the plating bath was the same as in Example 1 except for those shown in Table 2 below.
The same as in Example 1.

Pt was used for the anode, the substrate and the anode were accommodated in a cell, and plating was performed by a parallel flow method in which a plating solution was allowed to flow at a high speed in the gap between these. The dimensions of the cell were 1 cm in height, 3 cm in width, and 5 cm in length. A base was placed on the bottom of the cell, and an anode was placed facing the base. Then, a plating solution was flowed at a flow rate of 50 m / s in the length direction of the cell.

When a plating bath containing Pd ions was used, a voltage was applied to the substrate in a cycle of 22 V (1 second) → 0 V (40 seconds), and this cycle was repeated 45 times to obtain a thickness of about 1 μm. Was formed.

When a plating bath containing Cu ions is used, the substrate is charged from 20 V (2 seconds) to 0 V (80 seconds).
, And the cycle was repeated 45 times.

The ratio between the Co content and the Fe content in the soft magnetic thin film was almost the same as the ratio between Co ions and Fe ions in the plating bath, and the M content was 2 atomic% or less. The intermediate thin film had M as a main component and Co and Fe.

The soft magnetic thin film was formed during the voltage application, and the intermediate thin film was formed when the voltage application was stopped.

For each of these samples, the same measurement as in Example 1 was performed. The results are shown in Table 2 below.

[0129]

[Table 2]

Example 3 Using a plating bath described below, a soft magnetic thin film was formed by an electroplating method, and an intermediate thin film was formed by an electroless plating method to prepare a multilayer plating sample.

Plating bath Cobalt sulfamate: 0.2 mol / l Iron sulfamate: 0.2 mol / l Boric acid: 0.5 mol / l Sodium hypophosphite: 0.8 mol / l Ammonium chloride: 0.5 mol / l sulfuric acid Copper: 80 pp of Cu ion = Co ion + Fe ion
m The plating bath temperature was 40 ° C., and the pH of the plating bath was 8.0.

The voltage was applied from 18 V (1 second) to 0 V
(20 seconds) cycle was repeated 45 times.

The thickness of the soft magnetic thin film of this multilayer plating film sample was 200 A, and the thickness of the intermediate thin film was 20 A. Various characteristics were almost the same as those of Sample No. 1-3 shown in Table 1.

Further, a soft magnetic thin film was formed by an electroless plating method and an intermediate thin film was formed by an electroplating method using the following plating bath to prepare a multilayer plating sample.

Plating bath Cobalt chloride: 0.3 mol / l Iron chloride: 0.3 mol / l Boric acid: 0.5 mol / l Sodium hypophosphite: 0.4 mol / l Sodium chloride: 0.5 mol / l Copper sulfate: Cu ion = 50 pp of Co ion + Fe ion
m The plating bath temperature was 80 ° C., and the pH of the plating bath was 8.0.

The voltage was applied from 2.2 V (40 seconds) →
The cycle of 0 V (60 seconds) was repeated 45 times.

The thickness of the soft magnetic thin film of this multilayer plating film sample was 200 A, and the thickness of the intermediate thin film was 20 A. Various characteristics were almost the same as those of Sample No. 1-3 shown in Table 1.

[Embodiment 4] In each of the above embodiments, Cu
When a multilayer plating film was prepared using Pt, Au, Ag, Ir, Rh, or Ru instead of the above, substantially the same results as those in the above examples were obtained.

[Example 5] The multilayer plating film sample No. 1-9 produced in Example 1 was subjected to a heat treatment at 300 ° C for 30 minutes. As a result, λs was reduced to 0.2 × 10 ^-5 and μ was increased to 2000.

Example 6 A thin-film magnetic head of the present invention having the structure shown in FIG. 1 was manufactured. For the lower magnetic pole layer 41 and the upper magnetic pole layer 45, a multilayer plating film formed in the same manner as in Sample No. 1-9 of Example 1 was used. However, the thickness of the intermediate thin film is 30A, and the number of laminations of the soft magnetic thin film is 140A.
And

For comparison, a thin-film magnetic head having a 3.0 μm-thick Ni ₈₀ Fe ₂₀ single-layer film formed by electroplating as the lower and upper magnetic pole layers was manufactured.

For these thin-film magnetic heads, Hc =
Comparing overwrite characteristics (13.44 MHz-3.36 MHz, 50 mA _op ) to a 1500 Oe magnetic recording medium, the magnetic head of the present invention showed a value 8 dB higher than the comparative magnetic head.

The advantages of the present invention are clear from the above embodiments.

[0144]

According to the present invention, a multilayer plating film having a high saturation magnetic flux density and excellent soft magnetic properties can be realized by using a liquid phase plating method having a low equipment cost and a high mass productivity.

[Brief description of the drawings]

FIG. 1 is a sectional view partially showing a floating type thin film magnetic head which is a preferred embodiment of a magnetic head according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 thin-film magnetic head 20 base 31, 33, 35 insulating layer 41 lower magnetic pole layer 45 upper magnetic pole layer 50 gap layer 60 coil layer 70 protective layer

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ identification symbol FI // C23C 14/46 C23C 14/46 (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01F 41/26 C25D 7 / 00 G11B 5/147 H01F 10/00 H01F 10/16 C23C 14/46

Claims (10)

(57) [Claims] 1. The method according to claim 1, wherein substantially Co, Fe and M (wherein
M is Pd, Cu, Pt, Au, Ag, Ir, Rh or Ru. ), And a method of manufacturing a soft magnetic multilayer plating film in which an intermediate thin film having a higher M content than the soft magnetic thin film is alternately laminated. When the plating bath used for forming the intermediate thin film has a total content of Co ions and Fe ions = 0.05 to 10
mol / l, Co ion / (Co ion + Fe ion) = 0.4-
A method for producing a soft magnetic multilayer plating film, wherein 0.8 (molar ratio) and M ion content = 10 to 1000 ppm of the total weight of Co ions and Fe ions. 2. The method according to claim 1, wherein the soft magnetic thin film is formed by electroplating, and the intermediate thin film is formed by electroplating, displacement plating, or electroless plating. . 3. The method according to claim 1, wherein the soft magnetic thin film is formed by an electroless plating method, and the intermediate thin film is formed by an electroplating method. 4. The method for producing a soft magnetic multilayer plating film according to claim 1, wherein a heat treatment is performed after forming the soft magnetic multilayer plating film. 5. The formula (Co _x Fe _1-x ) _{1- y My} (where M is Pd, Cu, Pt, A
u, Ag, Ir, Rh or Ru, and x and y represent atomic ratios, 0.4 ≦ x ≦ 0.8, y ≦ 0.
It is one. A) a soft magnetic thin film having a composition represented by:
A soft magnetic multilayer plating film characterized in that intermediate thin films having a higher M content than the soft magnetic thin film are alternately laminated. 6. The soft magnetic multilayer plating film according to claim 5, wherein the saturation magnetic flux density is 20 kG or more. 7. The method according to claim 6, wherein M is Pd, and the saturation magnetostriction constant λs
The soft magnetic multilayer plating film according to claim 5 or 6, wherein is less than + 3 × 10 ^-6 . 8. The soft magnetic multilayer plating film according to claim 5, wherein said soft magnetic thin film has a thickness of 5000 A or less, and said intermediate thin film has a thickness of 2500 A or less. 9. A method for producing a soft magnetic multilayer plating film according to any one of claims 1 to 4.
9. The soft magnetic multilayer plating film according to any one of items 8 to 8. 10. A magnetic head comprising the soft magnetic multilayer plating film according to claim 5 as a magnetic pole.