JP2001250719A - Magnetic device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that an insulating layer used for insulating a magnetic layer from a coil layer is formed of polyimide resin whose curing temperature is 350 deg.C or above in a conventional magnetic device, so that the magnetic layer deteriorates in resistivity due to heat applied when the insulating layer is formed. SOLUTION: The insulating layers 6, 8, and 10 of a thin film inductor are formed of novolak positive resist whose curing temperature is 250 deg.C or below, by which insulating layers can be formed at a lower temperature, and thus magnetic layers 5 and 9 can be prevented from deteriorating in resistivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic element such as a thin film inductor or a thin film transformer manufactured in a step including a film forming process, and in particular, by forming a magnetic layer using a magnetic material having a high specific resistance. The present invention also relates to a magnetic element capable of reducing the loss equivalent resistance of the magnetic element and improving the performance coefficient of the magnetic element, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Information communication electronic equipment represented by a portable telephone has been rapidly spread due to realization of portability and long operation time due to reduction in size and weight. Along with the miniaturization and weight reduction of electronic devices, the demand for miniaturization and weight reduction of a power supply which is a power supply source is increasing, and it is necessary to further reduce a thin film inductor which is an energy storage element of a switching power supply.

In order to reduce the size of a thin film inductor, it is necessary to increase the flux linkage, and a magnetic film having high magnetic permeability is used for the thin film inductor. As one form of a thinned thin film inductor, there is an internal coil type thin film inductor in which magnetic thin films are arranged above and below a coil layer via an insulating layer. More specifically, in the internal coil type thin-film inductor, a first magnetic layer is formed on a substrate, a coil layer is formed on the first magnetic layer via an insulating layer, and an insulating layer is formed on the coil layer. A second magnetic layer is formed via a layer.

Conventionally, as a material for forming an insulating layer for insulating the first and second magnetic layers and the coil layer, a polyimide resin having a high viscosity and capable of easily forming a thick insulating layer has been used. I was

[0005]

When the magnetic layer is formed above and below the coil layer, the inductance increases, but an eddy current is generated in the magnetic layer. Generally, the driving frequency of a thin-film inductor is in the region of several MHz, and the influence of eddy current loss appears remarkably.

In order to reduce the eddy current loss in the magnetic layer, it is necessary to increase the specific resistance of the magnetic layer.

However, when heat treatment is performed on the formed magnetic layer, the specific resistance of the magnetic layer is significantly reduced as compared with immediately after the film formation. For example, when the magnetic layer is subjected to a heat treatment at about 400 ° C., the specific resistance of the magnetic layer becomes about half as compared to immediately after the film formation.

Conventionally, a polyimide resin has been used as a material for forming an insulating layer for insulating the first and second magnetic layers and the coil layer. However, the curing temperature of the polyimide resin is 350 C. to 500.degree. Therefore, when an insulating layer is formed using a polyimide resin, when the polyimide resin is cured by applying heat, the specific resistance of the magnetic layer is greatly reduced, and the eddy current loss of the thin film inductor is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to suppress a decrease in specific resistance of a magnetic layer in a manufacturing process and to reduce an eddy current loss and a magnetic element. It is intended to provide a manufacturing method.

[0010]

According to the present invention, there is provided a magnetic element comprising a coil, a magnetic layer covering the coil, and a thermosetting resin insulating layer formed between the coil and the magnetic layer. The device is characterized in that the curing temperature of the thermosetting resin forming the insulating layer is lower than the temperature at which the specific resistance of the magnetic layer is reduced by 10% from immediately after film formation.

In the present invention, the thermosetting resin preferably has a curing temperature of 300 ° C. or less.

When the curing temperature of the thermosetting resin for forming the insulating layer is 300 ° C. or less, the decrease in the specific resistance of the magnetic layer in the step of forming the insulating layer is determined by the specific resistance immediately after the film formation. 10% or less.

The thermosetting resin that can be used in the present invention includes, for example, novolak resins, olefin resins, epoxy resins, phenol resins, polyester resins, and acrylic resins.

Further, in the present invention, the thickness of the insulating layer is set to 1
It can be 0 μm or more. Preferably, in order to improve the characteristics of the magnetic element, magnetic anisotropy in a predetermined direction is induced in the magnetic layer.

The present invention is particularly effective when the magnetic layer is formed of a magnetic material in which a microcrystalline phase mainly composed of a magnetic element and an amorphous phase having high electric resistance are mixed.

When the magnetic layer is formed by using a magnetic material having a microcrystalline phase mainly composed of a magnetic element and high heat is applied to the magnetic layer, the microcrystalline phase grows and the specific resistance is significantly reduced. Resulting in.

As a magnetic material in which a microcrystalline phase mainly composed of a magnetic element and an amorphous phase having a high electric resistance are mixed, for example, a microcrystalline phase mainly composed of Fe and / or Co;
Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al,
One or more elements M selected from Si, Cr, P, C, B, Ga, Ge and rare earth elements;
Alternatively, there is a magnetic material having a structure in which an amorphous phase containing a large amount of N is mixed.

The rare earth element is a lanthanide element (L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu) and Sc,
It shows 17 elements of Y.

Further, the method for manufacturing a magnetic element according to the present invention comprises:
(A) forming a first magnetic layer on an insulating substrate in a magnetic field in a predetermined direction; and (b) forming a specific resistance of the first magnetic layer on the first magnetic layer. A step of forming a first insulating layer using a thermosetting resin which is cured at a temperature lower than the temperature immediately after by 10%; and (c) forming a pattern of a coil layer on the first insulating layer. And (d) using a thermosetting resin that cures on the coil layer at a temperature lower than the temperature at which the specific resistance of the first magnetic layer decreases by 10% from immediately after the film formation, and Forming an insulating layer;
(E) forming a second magnetic layer on the second insulating layer in a magnetic field in the same direction as the magnetic field in the step (a).

After the step (e), (f) a temperature lower than the temperature at which the specific resistances of the first and second magnetic layers are reduced by 10% on the second magnetic layer immediately after the film formation. Forming a third insulating layer using a thermosetting resin that cures at a low temperature.

In the step (b), the step (d), and / or the step (f), the temperature of the magnetic layer in the step (a) and the step (e) is lower than the temperature at the time of film formation in a magnetic field. It is preferable to form the insulating layer using a thermosetting resin that cures in step (a).

Or (b) and (d) and / or
Alternatively, in the step (f), the insulating layer is preferably formed using a thermosetting resin having a curing temperature of 300 ° C. or lower.

In the present invention, in the step (b), the step (d), and / or the step (f), the insulating layer may be made of, for example, a novolak resin, an olefin resin, an epoxy resin, a phenol resin, It can be formed of either a polyester resin or an acrylic resin.

In the present invention, in the steps (b), (d), and / or (f), the insulating layer may be formed with a thickness of 10 μm or more.

Further, in the steps (a) and (e), the first magnetic layer and the second magnetic layer are made of a microcrystalline phase mainly composed of a magnetic element and an amorphous phase having a high electric resistance. It can be formed of mixed magnetic materials.

As a magnetic material in which a microcrystalline phase mainly composed of a magnetic element and an amorphous phase having a high electric resistance are mixed, for example, a microcrystalline phase mainly composed of Fe and / or Co;
Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al,
One or more elements M selected from Si, Cr, P, C, B, Ga, Ge and rare earth elements;
Alternatively, there is a magnetic material having a structure in which an amorphous phase containing a large amount of N is mixed.

The rare earth element is a lanthanide element (L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu) and Sc,
It shows 17 elements of Y.

[0028]

FIG. 1 is a sectional view showing a thin-film inductor (flat magnetic element) as an embodiment of the present invention.

In this thin-film inductor, an extraction electrode 3 is formed on a substrate 1. The extraction electrode 3 also has a function as a terminal. An insulating layer 4, a magnetic layer 5, and an insulating layer 6 are sequentially laminated thereon, and a spiral coil-shaped planar coil 7 is formed on the insulating layer 6. The central portion 7a of the planar coil 7 is connected to the extraction electrode 3 via through holes formed in the insulating layer 4, the magnetic layer 5, and the insulating layer 6. Further, an insulating layer 8 covering the planar coil 7 is formed, and a magnetic layer 9 is formed on the insulating layer 8. The insulating layers 6 and 8 are provided to prevent a short circuit due to conduction with the magnetic layers 5 and 9 when the planar coil 7 is energized. An extraction electrode (not shown) extends from the end of the planar coil 7 onto the substrate 1. Further, an insulating layer 10 for protecting the thin-film inductor is formed on the magnetic layer 9.

The planar coil 7 is made of a highly conductive metal material such as copper, silver, gold, aluminum or an alloy thereof, and is electrically connected in series or in parallel depending on inductance, DC superimposition characteristics, size, and the like. In addition, they can be appropriately arranged vertically or horizontally via an insulating layer.

Further, the planar coil 7 can be formed into various shapes by forming a conductive layer on a substrate and then performing photoetching. As a method for forming the conductive layer, press bonding,
An appropriate method such as plating, metal spraying, vacuum deposition, sputtering, ion plating, and screen printing and baking may be used.

The magnetic layers 5 and 9 are made of, for example, Fe
It can be formed using a soft magnetic material represented by ₅₀ Hf ₁₆ O ₃₄ .

The magnetic properties of the magnetic layers 5 and 9 formed by using a soft magnetic material represented by the composition formula Fe ₅₀ Hf ₁₆ O ₃₄ were 1090 μΩ · cm.

The magnetic layers 5 and 9 can be formed, for example, by a sputtering method using an existing sputtering apparatus such as magnetron sputtering, RF bipolar sputtering, RF tripolar sputtering, ion beam sputtering, and facing target type sputtering.

Alternatively, in addition to sputtering, vapor deposition or MBE
(Molecular-beam-epitaxy) method, ICB
A film forming process such as an (ion-cluster-beam) method can be used.

In the soft magnetic material represented by Fe ₅₀ Hf ₁₆ O ₃₄ , the microcrystalline phase mainly composed of the magnetic element Fe is mixed with the amorphous phase of high electric resistance mainly composed of the oxide of the non-conductive element Hf. Magnetic material.

FIG. 3 shows that a microcrystalline phase mainly composed of Fe, which is a conductive magnetic element, is changed to an amorphous phase mainly composed of an oxide (or nitride) of a non-conductive element M such as Hf. FIG. 3 is a pattern diagram of a soft magnetic thin film formed by mixed magnetic materials.

The element M is an element necessary for achieving both soft magnetic characteristics and high resistance. These elements are easily bonded to oxygen, form oxides, are mainly distributed in the amorphous phase, Improve the specific resistance ρ of the film.

When the soft magnetic thin film shown in FIG. 3 is subjected to a heat treatment at a temperature of 300 ° C. or more, fine crystals mainly composed of Fe grow in grains, and the specific resistance decreases. For example, Fe ₅₀ Hf ₁₆ O ₃₄
Magnetic layers 5, 9 formed using a soft magnetic material represented by
The specific resistance immediately after film formation is 1090 μΩ · cm,
The resistivity after annealing at 400 ° C in a static magnetic field is 6
25 Ω · cm, which is 40% lower than the specific resistance immediately after film formation.

In the present embodiment, the insulating layers 6, 8, and 1
Numeral 0 is formed of a novolak-based positive resist which is a thermosetting resin. The insulating layers 6, 8, and 10 are formed by a method such as baking after paste printing or spin coating, hot-dip plating, thermal spraying, vapor phase plating, vacuum deposition, sputtering, or ion plating. This positive resist has a curing temperature of 200 ° C. to 25 ° C.
It is in the range of 0 ° C. Therefore, in the process of manufacturing the thin film inductor of FIG. 1, when the insulating layers 6, 8, and 10 are thermally cured, the decrease in the specific resistance of the magnetic layer can be suppressed to 10% or less of the specific resistance immediately after the film formation. it can.

When the thin-film inductor is soldered on the substrate, heat is applied to the thin-film inductor at about 250 ° C., so that the insulating layers 6, 8, and 10 have a curing temperature of 2 ° C.
It is preferably formed of a thermosetting resin having a heat resistance of 50 ° C. or higher.

The novolak-based positive resist used in the present invention has a high viscosity, and the thickness of the insulating layers 6, 8, and 10 can be increased to 10 μm or more.

In the present invention, the insulating layers 6, 8, and 1
As the thermosetting resin used to form 0, an olefin resin, an epoxy resin, a phenol resin, a polyester resin, an acrylic resin, or the like may be used. The curing temperature of these thermosetting resins is 120 ° C.
1 to 250 ° C., no matter which thermosetting resin is used, when the insulating layers 6, 8, and 10 are thermally cured in the manufacturing process of the thin film inductor of FIG. 1, the specific resistance of the magnetic layer decreases. Can be reduced to 10% or less of the specific resistance immediately after film formation.

In the thin-film inductor of the present embodiment, the magnetic layers 5 and 9 are provided with induced magnetic anisotropy in the same direction. When induced magnetic anisotropy is imparted to the magnetic layer 5 and the magnetic layer 9, the inductance can be obtained by exciting the magnetic layer 5 and the magnetic layer 9 in the hard axis direction. Characteristics can also be improved.

However, the magnetic layers 5 and 9 may be isotropic magnetic layers. FIG. 2 is a sectional view showing a thin film transformer as another embodiment of the present invention.

In this thin-film transformer, an extraction electrode 18 is formed on a substrate 11. On top of this, the insulating layer 12
, A magnetic layer 13 and an insulating layer 14 are sequentially laminated.
The insulating layer 14 is formed stepwise. When the lowermost layer 14a is formed, a primary coil 15 is formed on the lower layer 14a by a conductor spirally wound in a plane. Insulating layer 1 on it
4 intermediate layer 14b is formed thereon, and the primary coil 15
The secondary coil 16 having a different number of turns is formed so as to be spirally wound in a plane, and the insulating layer 14 is formed thereon.
Is formed.

The winding center portion 15a of the primary coil 15 is located at the lowermost layer 14a of the insulating layer 12, the magnetic layer 13 and the insulating layer 14.
Material 1 filled in the through hole opened in
It is connected to the extraction electrode 18 by 8a. Also,
The winding center portion of the secondary coil 16 also includes the insulating layer 12 and the magnetic layer 1.
3 and through holes formed in the insulating layer 14 are connected to another extraction electrode (not shown). Also, the outer winding end of the primary coil 15 and the outer winding end of the secondary coil 16
It is connected to an unillustrated extraction electrode formed on the substrate 11.

Further, a magnetic layer 17 is formed on the uppermost layer 14c of the insulating layer 14, and the magnetic layer 17 and the magnetic layer 13 are magnetically joined all around. An insulating layer 19 for protecting the thin film transformer is laminated on the magnetic layer 17.

The primary coil 15 and the secondary coil 16 are
Made of a highly conductive metal material such as copper, silver, gold, aluminum or their alloys, electrically insulated in series or parallel, and further vertically or horizontally, depending on inductance, DC superimposition characteristics, size, etc. They can be appropriately arranged via a film. Further, the primary coil 15 and the secondary coil 16 can be formed into various shapes by forming a conductive layer on a substrate and then performing photoetching. As a method for forming the conductive layer, an appropriate method such as press bonding, plating, metal spraying, vacuum evaporation, sputtering, ion plating, or screen printing firing may be used.

The magnetic layers 13 and 17 can be formed using a soft magnetic material whose composition formula is represented by Fe ₅₀ Hf ₁₆ O ₃₄ , similarly to the thin film inductor of FIG.

When the magnetic properties of the magnetic layers 13 and 17 formed using a soft magnetic material represented by the composition formula of Fe ₅₀ Hf ₁₆ O ₃₄ were measured, the specific resistance was 1090 μΩ · cm.

The magnetic layers 13 and 17 can be formed by a sputtering method using an existing sputtering apparatus such as magnetron sputter, RF bipolar sputter, RF tripolar sputter, ion beam sputter, and facing target type sputter.

Alternatively, in addition to sputtering, evaporation or MBE
(Molecular-beam-epitaxy) method, ICB
A film forming process such as an (ion-cluster-beam) method can be used.

Also in the present embodiment, the insulating layer 14 is formed of a novolak-based positive resist, which is a thermosetting resin, in all of the lowermost layer 14a, the intermediate layer 14b, and the uppermost layer 14c. The insulating layer 19 is also formed of the same novolak-based positive resist. This positive resist has a curing temperature in the range of 200 ° C to 250 ° C. Therefore, in the manufacturing process of the thin film transformer of FIG.
When the lowermost layer 14a, the intermediate layer 14b, the uppermost layer 14c, and the insulating layer 19 are thermally cured, the insulating layer 14 reduces the specific resistance of the magnetic layers 13 and 17 by 10% of the specific resistance immediately after the film formation.
The following can be included.

The lowermost layer 14a and the intermediate layer 14b of the insulating layer 14
The uppermost layer 14c and the insulating layer 17 are formed by a method such as baking after paste printing or spin coating, a hot-dip plating method, thermal spraying, vapor phase plating, vacuum deposition, sputtering, or ion plating.

The positive resist used in the present invention has a high viscosity, and the lowermost layer 14a of the insulating layer 14 and the intermediate layer 14b
The thickness of the uppermost layer 14c and the insulating layer 19 can be set to 10 μm or more.

In the present invention, the lowermost layer 1 of the insulating layer 14 is
4a, the intermediate layer 14b and the uppermost layer 14c, and the insulating layer 19
As the thermosetting resin used for forming the resin, an olefin resin, an epoxy resin, a phenol resin, a polyester resin, an acrylic resin, or the like may be used. The curing temperature of these thermosetting resins is from 120 ° C. to 250 ° C., and using any thermosetting resin,
In the manufacturing process of the thin film inductor of FIG.
In addition, when the insulating layer 19 is thermally cured, the decrease in the specific resistance of the magnetic layers 13 and 17 can be suppressed to 10% or less of the specific resistance immediately after the film formation.

When the thin film transformer is soldered on a substrate, heat of about 250 ° C. is applied to the thin film transformer, so that the insulating layers 14 and 19 have a curing temperature of 25 ° C.
It is preferably formed of a thermosetting resin having a heat resistance of 0 ° C. or higher.

In the thin film transformer of the present embodiment, the magnetic layers 13 and 17 are provided with induced magnetic anisotropy in the same direction.

However, the magnetic layers 5 and 9 may be isotropic magnetic layers. Also, the magnetic layers 5 and 9 of the thin film inductor of FIG. 1 and the magnetic layers 13 and 1 of the thin film transformer of FIG.
7 can be formed using not only the soft magnetic material represented by the above composition formula but also a soft magnetic material shown below.

A microcrystalline phase mainly composed of Fe and / or Co, Ti, Zr, Hf, V, Nb, Ta, Mo, W,
One or more elements M selected from Al, Si, Cr, P, C, B, Ga, Ge and rare earth elements;
And / or a magnetic material having a structure in which an amorphous phase containing a large amount of N is mixed.

The crystal structure of the microcrystalline phase is bcc
It is preferable that the crystal structure is composed of one or more of a hybrid structure, a hcp structure, and an fcc structure. More preferably, the crystal structure of the microcrystalline phase is mainly composed of a bcc structure.

The average crystal grain size of the microcrystalline phase is 3
It is preferably 0 nm or less. This magnetic material is formed, for example, with the following composition. _{(Fe 1-a Co a)} x M y L z O w , however, M is, Zr, Hf, V, Nb , Ta, Mo,
One or more elements selected from W, Al, Si, Cr, P, C, B, Ga, Ge and rare earth elements;
L is Pt, Ru, Rh, Pd, Ir, Os, Sn, T
one or more elements selected from i, Au, Ag, and Cu, and a indicating a composition ratio is 0 ≦ a ≦ 0.5,
x, y, z, w are at%, 5 ≦ y ≦ 30, 0 ≦ z ≦ 2
0, 5 ≦ w ≦ 40, 10 ≦ y + z ≦ 40, and the remainder is x.

More preferably, a indicating the composition ratio of the soft magnetic film is 0 ≦ a ≦ 0.3, and x, y, z and w are at%.
Where 7 ≦ y ≦ 15, 0 ≦ z ≦ 5, 20 ≦ w ≦ 35, and the remainder is x.

The element M is preferably an element containing one or both of Zr and Hf.

Further, the composition a of the soft magnetic film is 0 and the composition Z is 0 at%, that is, it is preferable that the magnetic material is a Fe-MO type magnetic material.

The magnetic material may be formed with the following composition. _{(Co 1-a T a)} x M y L z O w , however, T is an element including Fe, one or both either of Ni, M is, Ti, Zr, Hf, Nb ,
Ta, Cr, Mo, Si, P, C, W, B, Al, G
a, Ge and one or more elements selected from rare earth elements, and L is Au, Ag, Cu, Ru, Rh,
One or more elements selected from Os, Ir, Pt, and Pd, and a indicating a composition ratio is 0 ≦ a ≦ 0.
5, x, y, z, w are at%, 3 ≦ y ≦ 30, 0 ≦ z
≦ 20, 7 ≦ w ≦ 40, and 20 ≦ y + z + w ≦ 60, and the remainder is x.

A indicating the composition ratio of the soft magnetic film is as follows:
0 ≦ a ≦ 0.3, x, y, z, w are at%, and 7 ≦ y ≦
15, 0 ≦ z ≦ 19, 20 ≦ w ≦ 35, 30 ≦ y + z +
More preferably, the relationship of w ≦ 50 is satisfied, and the balance is x.

The element T is preferably Fe. In this case, the concentration ratio between Co and Fe is 0.5 ≦ ｛C
It is preferable that o / (Co + Fe)｝ ≦ 0.8.

Further, in the present invention, N may be used instead of O, or N together with O, as one element constituting the above-described magnetic material.

A method for manufacturing the thin film inductor shown in FIG. 1 will be described. First, an extraction electrode 3 is formed on the insulating substrate 1 by using a conductive material such as Cu by a plating method, a sputtering method, or the like, and an insulating layer 4 is laminated on the extraction electrode 3.

Next, a magnetic layer 5 (first magnetic layer) is formed on the insulating layer 4 in a magnetic field in a predetermined direction, and the induced magnetic anisotropy is formed on the magnetic layer 5 simultaneously with the formation of the magnetic layer 5. Is given.

In this embodiment, the magnetic layer 5 is made of Fe ₅₀ Hf
It is formed using a soft magnetic material represented by ₁₆ O ₃₄ . In the present invention, since the induced magnetic anisotropy is imparted to the magnetic layer 5 by forming the magnetic layer 5 in a magnetic field, the magnetic layer 5 is heat-treated in a magnetic field after the magnetic layer 5 is formed. No need to do. The temperature of the magnetic layer 5 during the formation of the magnetic layer 5 is about 250 ° C.

Further, an insulating layer 6 (first insulating layer) is formed on the magnetic layer 5 using a novolak-based positive resist which is a thermosetting resin. The insulating layer 6 is formed by a method such as baking after paste printing or spin coating, a hot-dip plating method, thermal spraying, vapor phase plating, vacuum deposition, sputtering, or ion plating. This positive resist has a curing temperature in the range of 200 ° C to 250 ° C. Therefore, the temperature of the magnetic layer 5 when the insulating layer 6 is thermally cured also becomes 250 ° C. or less, and the decrease in specific resistance can be suppressed to 10% or less of the specific resistance immediately after film formation.

In this embodiment, the magnetic layer 5 is made of Fe ₅₀ Hf ₁₆ O
_34, and the specific resistance immediately after film formation is 109
Although the specific resistance was 0 μΩ · cm, the specific resistance after the insulating layer 6 was laminated and heat-treated was 1030 μΩ · cm, and the specific resistance was reduced by only 5%.

In the present invention, an olefin resin, an epoxy resin, a phenol resin, a polyester resin, an acrylic resin, or the like may be used as the thermosetting resin used to form the insulating layer 6. Good. The curing temperature of these thermosetting resins is from 120 ° C. to 250 ° C.
When any of the thermosetting resins is used, when the insulating layer 6 is thermoset, the decrease in the specific resistance of the magnetic layer can be suppressed to 10% or less of the specific resistance immediately after the film formation.

Next, after a conductive layer is formed on the insulating layer 6, the planar coil 7 having a spiral coil shape is formed by photoetching. As a method for forming the conductive layer, an appropriate method such as press bonding, plating, metal spraying, vacuum evaporation, sputtering, ion plating, or screen printing firing may be used. Central part 7 of plane coil 7
a is connected to the extraction electrode 3 through through holes formed in the insulating layer 4, the magnetic layer 5, and the insulating layer 6. The planar coil 7 is made of a highly conductive metal material such as copper, silver, gold, aluminum, or an alloy thereof, and is electrically connected in series or in parallel, and further vertically, depending on the inductance, DC superimposition characteristics, size, and the like. Or laterally via an insulating film.

Next, an insulating layer 8 (second insulating layer) is formed on the planar coil 7 by using the same novolak-based positive resist used for forming the insulating layer 6. The thermosetting temperature when forming the insulating layer 8 is also from 200 ° C. to 250 ° C.
In the range. When the thermosetting temperature at the time of forming the insulating layer 8 is equal to or lower than the thermosetting temperature at the time of forming the insulating layer 6, the specific resistance of the magnetic layer 5 does not decrease when the insulating layer 8 is thermoset.

Further, a magnetic layer 9 (second magnetic layer) is formed on the insulating layer 8 in a magnetic field in the same direction as the magnetic field applied when the magnetic layer 5 was formed. At the same time as the film is formed, induced magnetic anisotropy is imparted to the magnetic layer 9.

The magnetic layer 9 is also formed using a soft magnetic material represented by Fe ₅₀ Hf ₁₆ O ₃₄ . In the present invention, since the induced magnetic anisotropy is imparted to the magnetic layer 9 by forming the magnetic layer 9 in a magnetic field, the magnetic layer 9 is heat-treated in a magnetic field after the magnetic layer 9 is formed. No need to do. Therefore, it is possible to prevent the specific resistance of the magnetic layer 5 and the magnetic layer 9 from being lowered by the heat treatment in the magnetic field after the formation of the magnetic layer 9. The temperature of the magnetic layer 9 during the formation of the magnetic layer 9 is about 25.
0 ° C.

Finally, an insulating layer 10 (third insulating layer) is formed on the magnetic layer 9 by using the same novolak-based positive resist used for forming the insulating layers 6 and 8. . The thermosetting temperature when forming the insulating layer 10 is also 200.
In the range of from 250C to 250C. Accordingly, the temperature of the magnetic layer 9 when the insulating layer 10 is thermally cured also becomes 250 ° C. or less, and the decrease in specific resistance can be suppressed to 10% or less of the specific resistance immediately after film formation. When the thermosetting temperature at the time of forming the insulating layer 10 is equal to or lower than the thermosetting temperature at the time of forming the insulating layers 6 and 8, the specific resistance of the magnetic layer 5 decreases when the insulating layer 10 is thermoset. do not do.

The novolak-based positive resist used in the present invention has a high viscosity, and the thickness of the insulating layers 6, 8, and 10 can be set to 10 μm or more.

The insulating layers 8 and 10 are also made of an olefin resin, an epoxy resin, a phenol resin, a polyester resin, an acrylic resin, or the like whose thermosetting temperature is in the range of 120 ° C. to 250 ° C. It may be formed and used.

The method of manufacturing the thin film transformer of FIG. 2 is basically the same as the method of manufacturing the thin film inductor described above.
Step of Forming Next Coil 16 and Top Layer 14 of Insulating Layer 14
The only difference is that the step of laminating c is added.

First, the magnetic layer 13 is formed in a magnetic field in a predetermined direction. Next, the lowermost layer 14a of the insulating layer 14, the intermediate layer 14
b, using a novolak-based positive resist having a thermosetting temperature of 200 ° C. to 250 ° C. as a material of the uppermost layer 14a,
The material of the primary coil 15 and the secondary coil 16 is copper, silver,
As shown in FIG. 2, from the bottom, the lowermost layer 14a, the primary coil 15, the intermediate layer 14b, the secondary coil 16, and the uppermost layer 14c are formed using a good conductive metal material such as gold, aluminum or an alloy thereof. Are sequentially formed. The temperature at which the lowermost layer 14a, the intermediate layer 14b, and the uppermost layer 14c of the insulating layer 14 are laminated and thermally cured is about 200 ° C to 250 ° C.
Further, the magnetic layer 17 is formed in a magnetic field in the same direction as when the magnetic layer 13 was formed, and the insulating layer 14 is formed on the magnetic layer 17.
The insulating layer 19 is formed at a thermosetting temperature of 200.degree. C. to 250.degree. C. using the same novolak-based positive resist used when forming the.

The induced magnetic anisotropy is imparted to the magnetic layers 13 and 17 by forming the magnetic layers 13 and 17 in a magnetic field, thereby forming the magnetic layers 13 and 17. After the film formation, it is not necessary to heat-treat the magnetic layers 13 and 17 in a magnetic field. Therefore, it is possible to prevent the specific resistance of the magnetic layer 13 and the magnetic layer 17 from being reduced by the heat treatment in the magnetic field after the formation of the magnetic layer 13 and the magnetic layer 17. The temperature during the formation of the magnetic layers 13 and 17 is about 250 ° C.

The temperature at which the lowermost layer 14a, the intermediate layer 14b, and the uppermost layer 14c of the insulating layer 14 are laminated and thermally cured is about 200 ° C. to about 250 ° C.
When the lowermost layer 14a, the intermediate layer 14b, and the uppermost layer 14c are thermally cured, the decrease in the specific resistance of the magnetic layer 13 and the magnetic layer 17 is reduced in the same manner as in the above-described embodiment of the method of manufacturing the thin film inductor of FIG. The resistivity can be reduced to about 10% or less of the specific resistance immediately after film formation.

The novolak-based positive resist used in the present embodiment has a high viscosity, and the thickness of the lowermost layer 14a, the intermediate layer 14b, the uppermost layer 14c, and the insulating layer 19 of the insulating layer 14 should be 10 μm or more. Is possible.

Further, in the method for manufacturing a magnetic element of the present invention,
The insulating layers 6, 8, and 10 of the thin film inductor or the insulating layers 14 and 19 of the thin film transformer are cured at a temperature of 250 ° C. or less using a novolak-based positive resist or the like. The time required for heating and cooling the insulating layer can be reduced as compared with the conventional manufacturing method in which polyimide is cured at a temperature of about 400 ° C.

The magnetic layers 5 and 9 of the thin-film inductor of FIG. 1 and the magnetic layers 13 and 17 of the thin-film transformer of FIG.
Can be formed using not only the soft magnetic material represented by the above composition formula but also the following soft magnetic materials.

A microcrystalline phase mainly composed of Fe and / or Co, Ti, Zr, Hf, V, Nb, Ta, Mo, W,
One or more elements M selected from Al, Si, Cr, P, C, B, Ga, Ge and rare earth elements;
And / or a magnetic material having a structure in which an amorphous phase containing a large amount of N is mixed.

The rare earth element is a lanthanide element (L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu) and Sc,
It shows 17 elements of Y.

The crystal structure of the microcrystalline phase is bcc
It is preferable that the crystal structure is composed of one or more of a hybrid structure, a hcp structure, and an fcc structure. More preferably, the crystal structure of the microcrystalline phase is mainly composed of a bcc structure.

The average crystal grain size of the microcrystalline phase is 3
It is preferably 0 nm or less. This magnetic material is formed, for example, with the following composition. _{(Fe 1-a Co a)} x M y L z O w , however, M is, Zr, Hf, V, Nb , Ta, Mo,
One or more elements selected from W, Al, Si, Cr, P, C, B, Ga, Ge and rare earth elements;
L is Pt, Ru, Rh, Pd, Ir, Os, Sn, T
one or more elements selected from i, Au, Ag, and Cu, and a indicating a composition ratio is 0 ≦ a ≦ 0.5,
x, y, z, w are at%, 5 ≦ y ≦ 30, 0 ≦ z ≦ 2
0, 5 ≦ w ≦ 40, 10 ≦ y + z ≦ 40, and the remainder is x.

More preferably, a indicating the composition ratio of the soft magnetic film is 0 ≦ a ≦ 0.3, and x, y, z and w are at%.
Where 7 ≦ y ≦ 15, 0 ≦ z ≦ 5, 20 ≦ w ≦ 35, and the remainder is x.

The element M is preferably an element containing one or both of Zr and Hf.

Further, the composition a of the soft magnetic film is 0 and the composition Z is 0 at%, that is, it is preferable that the magnetic material is a Fe-MO type magnetic material.

The magnetic material may be formed with the following composition. _{(Co 1-a T a)} x M y L z O w , however, T is an element including Fe, one or both either of Ni, M is, Ti, Zr, Hf, Nb ,
Ta, Cr, Mo, Si, P, C, W, B, Al, G
a, Ge and one or more elements selected from rare earth elements, and L is Au, Ag, Cu, Ru, Rh,
One or more elements selected from Os, Ir, Pt, and Pd, and a indicating a composition ratio is 0 ≦ a ≦ 0.
5, x, y, z, w are at%, 3 ≦ y ≦ 30, 0 ≦ z
≦ 20, 7 ≦ w ≦ 40, and 20 ≦ y + z + w ≦ 60, and the remainder is x.

Further, a indicating the composition ratio of the soft magnetic film is as follows:
0 ≦ a ≦ 0.3, x, y, z, w are at%, and 7 ≦ y ≦
15, 0 ≦ z ≦ 19, 20 ≦ w ≦ 35, 30 ≦ y + z +
More preferably, the relationship of w ≦ 50 is satisfied, and the balance is x.

The element T is preferably Fe. In this case, the concentration ratio between Co and Fe is 0.5 ≦ ΔC
It is preferable that o / (Co + Fe)｝ ≦ 0.8.

Further, in the present invention, N may be used instead of O, or N together with O, as one element constituting the above-mentioned magnetic material.

Table 1 shows that Fe-Fe is a soft magnetic material that can be used to form a magnetic layer of the magnetic element of the present invention.
The figure shows the result of forming a soft magnetic thin film using Hf-O and measuring the composition ratio and magnetic properties. The composition ratio is measured by E
Performed by PMA.

[0103]

[Table 1]

No. No. 1 to No. 8 for each soft magnetic thin film, the specific resistance immediately after film formation (as dp) and 400
The specific resistance after heat treatment at ℃, the magnetic permeability μ 'up to 100 MHz, and the saturation magnetization Is were measured. From Table 1, No.
No. 1 to No. When the soft magnetic thin film No. 8 is subjected to a heat treatment at a temperature of 400 ° C., the specific resistance is reduced to about half.

When polyimide or the like is used for the insulating layer as in a conventional magnetic element, it is necessary to apply a temperature of about 400 ° C. to cure the polyimide. Therefore, for example, to obtain a magnetic element in which the specific resistance of the magnetic layer is 1000 μΩ · cm or more, the specific resistance at the time of film formation is 2000 μΩ.
The magnetic layer had to be formed using a soft magnetic material having a resistance of Ω · cm.

On the other hand, in the present invention, a thermosetting resin such as a novolak positive resist having a thermosetting temperature of 200 ° C. to 250 ° C. can be used for the insulating layer. The temperature can be around 250 ° C. Therefore, the decrease in the specific resistance of the magnetic layer in the manufacturing process is 5 to 10% or less. Therefore, when trying to obtain a magnetic element in which the specific resistance of the magnetic layer is 1000 μΩ · cm or more, when the magnetic element of No. 1 in Table 1 is used. No. 1 to No. Up to four soft magnetic thin films can be used. No. 1 to N
o. Each of the soft magnetic thin films up to 4 has a magnetic permeability of μ ′ = 1100 or more. In addition, No. No. 1 to No. 4
Soft magnetic materials up to 1.05 each have a saturation magnetization Is of 1.05
These values are shown.

As described above, according to the present invention, a decrease in the specific resistance of the magnetic layer of the magnetic element in the manufacturing process can be suppressed, and therefore, when a soft magnetic material for obtaining a magnetic layer having a specific resistance of a predetermined value is selected. In addition, it is possible to select a soft magnetic material having higher values of the magnetic permeability μ ′ and the saturation magnetization Is than in the related art.

[0108]

FIG. 4 is a graph showing the relationship between the heat treatment temperature after forming a magnetic layer of a magnetic element and the specific resistance of the magnetic layer.

A soft magnetic thin film is formed on a substrate by a sputtering method using a soft magnetic material having a composition formula of Fe ₅₂ Hf ₁₄ O ₃₄ , and then the soft magnetic thin film is heat-treated at various temperatures to have a specific resistance. Was examined for changes.

The specific resistance immediately after the film formation is defined as 100%, and the specific resistance after the heat treatment is expressed in percentage. From the curve of the graph, it can be seen that the resistivity decreases as the heat treatment temperature increases, and that the resistivity decreases particularly rapidly when the heat treatment temperature exceeds 300 ° C. Further, from the graph of FIG. 4, the heat treatment temperature is 200 ° C., 220 ° C., 250 ° C., 300 ° C.,
The specific resistances at 350 ° C. and 400 ° C. are respectively 98%, 97%, 95%, 90%, and 7% of the specific resistance immediately after film formation.
It can also be seen that they are 0% and 50%.

Therefore, as in the present invention, the thermosetting resin used as the material of the insulating layer laminated on the magnetic layer is a novolak resin, an olefin resin, an epoxy resin, a phenol resin having a curing temperature of 300 ° C. or lower. Using a resin, polyester resin, or acrylic resin,
The induced magnetic anisotropy is imparted by forming the magnetic layer in a magnetic field, and the heat treatment in the magnetic field after the film formation is performed so that the specific resistance of the magnetic layer is reduced. It can be seen that it can be kept within 10% or less.

Further, a soft magnetic thin film was formed using a soft magnetic material having a composition formula of Fe ₅₂ Zr ₁₄ O ₃₄ , and the heat treatment temperature after forming the soft magnetic thin film and the specific resistance of the soft magnetic thin film were compared. The relationship was examined, and the same result as in the above example in which a soft magnetic thin film was formed using a soft magnetic material having a composition of FeHfO was obtained.

[0113]

According to the magnetic element of the present invention described in detail above, the insulating layer is made of a thermosetting resin having a curing temperature lower than the temperature at which the specific resistance of the magnetic layer is reduced by 10% from immediately after the film formation. When a soft magnetic material for obtaining a magnetic layer having a specific resistance of a predetermined value is selected, a soft magnetic material having higher values of the magnetic permeability μ ′ and the saturation magnetization Is than before is selected. be able to.

Further, in the present invention, by using a thermosetting resin having a curing temperature of 300 ° C. or less, the decrease in the specific resistance of the magnetic layer in the step of forming the insulating layer can be prevented immediately after film formation. Can be reduced to 10% or less of the specific resistance.

In the present invention, the thickness of the insulating layer is set to 1
It can be 0 μm or more. In the method of manufacturing a magnetic element of the present invention, the magnetic layer is formed in a magnetic field to impart induced magnetic anisotropy, so that heat treatment in a magnetic field after the film formation is not performed, Forming the insulating layer with a thermosetting resin having a curing temperature lower than the temperature at which the specific resistance of the film is lower by 10% than immediately after the film formation, thereby obtaining a soft magnetic layer for obtaining a magnetic layer having a specific resistance of a predetermined value. When selecting a material, a soft magnetic material having higher values of the magnetic permeability μ ′ and the saturation magnetization Is than in the related art can be selected.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a thin film inductor as an embodiment of the present invention;

FIG. 2 is a sectional view showing a thin film transformer as another embodiment of the present invention;

FIG. 3 is a schematic diagram of a soft magnetic thin film constituting a magnetic layer of the magnetic element of the present invention.

FIG. 4 is a graph showing a relationship between a heat treatment temperature after forming a magnetic layer of a magnetic element and a specific resistance of the magnetic layer;

[Explanation of symbols]

 1,11 Substrate 4,6,8,10,12,14,19 Insulating layer 5,9,13,17 Magnetic layer 7 Planar coil 15 Primary coil 16 Secondary coil

Claims (15)

[Claims] 1. A magnetic element comprising a coil, a magnetic layer covering the coil, and an insulating layer of a thermosetting resin formed between the coil and the magnetic layer, wherein the thermal element forming the insulating layer is provided. A magnetic element, wherein a curing temperature of the curable resin is lower than a temperature at which the specific resistance of the magnetic layer is reduced by 10% from immediately after film formation. 2. The curing temperature of the thermosetting resin is 300 ° C.
The magnetic element according to claim 1, wherein: 3. The magnetic element according to claim 1, wherein the thermosetting resin is a novolak resin, an olefin resin, an epoxy resin, a phenol resin, a polyester resin, or an acrylic resin. . 4. The magnetic element according to claim 1, wherein said insulating layer has a thickness of 10 μm or more. 5. The magnetic element according to claim 1, wherein magnetic anisotropy in a predetermined direction is induced in the magnetic layer. 6. The magnetic element according to claim 1, wherein the magnetic layer is formed of a magnetic material in which a microcrystalline phase mainly composed of a magnetic element and an amorphous phase having high electric resistance are mixed. . 7. The magnetic material according to claim 1, wherein the magnetic material is Fe and / or Co.
Microcrystalline phase mainly composed of Ti, Zr, Hf, V, N
b, Ta, Mo, W, Al, Si, Cr, P, C, B,
7. The magnetic element according to claim 6, wherein the magnetic element has a structure in which one or more elements M selected from Ga, Ge and rare earth elements and an amorphous phase containing a large amount of elements O and / or N are mixed. 8. A step of (a) forming a first magnetic layer on an insulating substrate in a magnetic field in a predetermined direction; and (b) forming a first magnetic layer on the first magnetic layer. (C) forming a first insulating layer using a thermosetting resin that cures at a temperature lower than the temperature at which the specific resistance decreases by 10% from immediately after the film formation; and (c) forming a first insulating layer on the first insulating layer. (D) using a thermosetting resin that is cured on the coil layer at a temperature lower than the temperature at which the specific resistance of the first magnetic layer is reduced by 10% from immediately after film formation. Forming a second insulating layer; and (e) forming a second magnetic layer on the second insulating layer in a magnetic field in the same direction as the magnetic field in the step (a). And a method for manufacturing a magnetic element. 9. After the step (e), (f) a temperature lower than the temperature at which the specific resistance of the first and second magnetic layers is reduced by 10% on the second magnetic layer from immediately after film formation. 9. The method of manufacturing a magnetic element according to claim 8, further comprising: forming a third insulating layer using a thermosetting resin that cures at a low temperature. 10. In the step (b), the step (d), and / or the step (f), the steps (a) and (e)
The method for manufacturing a magnetic element according to claim 8, wherein the insulating layer is formed using a thermosetting resin that is cured at a temperature equal to or lower than a temperature at which the magnetic layer is formed in a magnetic field in the step. 11. The insulating layer is formed by using a thermosetting resin having a curing temperature of 300 ° C. or less in the steps (b), (d), and / or (f).
Or a method for manufacturing a magnetic element according to item 9. 12. In the step (b), the step (d) and / or the step (f), the insulating layer is made of a novolak resin, an olefin resin, an epoxy resin, a phenol resin, a polyester resin, 12. The method of manufacturing a magnetic element according to claim 8, wherein the magnetic element is formed of any one of an acrylic resin. 13. The magnetic element according to claim 8, wherein in the step (b), the step (d), and / or the step (f), the insulating layer is formed with a thickness of 10 μm or more. Manufacturing method. 14. In the steps (a) and (e), the first magnetic layer and the second magnetic layer are made of a microcrystalline phase mainly composed of a magnetic element and an amorphous phase having high electric resistance. 8. A method according to claim 8, wherein the magnetic material is formed of a mixed magnetic material.
3. The method for manufacturing a magnetic element according to any one of 3. 15. The method according to claim 15, wherein the first magnetic layer and the second magnetic layer include a microcrystalline phase mainly composed of Fe and / or Co;
i, Zr, Hf, V, Nb, Ta, Mo, W, Al, S
A magnetic material having a structure in which one or more elements M selected from i, Cr, P, C, B, Ga, Ge and rare earth elements and an amorphous phase containing a large amount of elements O and / or N are mixed. The method for manufacturing a magnetic element according to claim 14, wherein the magnetic element is formed of a material.