JP2003347123A - Thin-film inductor and electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a mounting area and efficiently use a magnetic flux for high efficiency. <P>SOLUTION: The thin-film inductor 10 has a structure wherein an interlayer insulation film 16, a lower magnetic thin film 19, an interlayer insulation film 20, a first layer conductor pattern 22, an interlayer insulation film 26, a second layer conductor pattern 28, an interlayer insulation film 32 and an upper magnetic thin film 34 are stuck in sequence on a substrate 12. The upper and lower magnetic thin films 18 and 34 are formed of nano-scale granular films. The first and second layer conductor patterns 22 and 28 are connected with each other in a nearly central part. The magnetic thin film is adopted so that an inductance value per unit wiring length can be increased, and since the magnetic flux concentrates in the magnetic thin film, the leakage of the magnetic flux is prevented and an inductance element is made more efficient. The double-layer structure of wiring can reduce an occupation area when compared with a case of a single-layer structure. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film inductor using a magnetic thin film made of a granular film and an electronic device using the same, and more specifically, to a thin film inductor and an electronic device suitable for use in a high frequency band. It is about.

[0002]

2. Description of the Related Art In recent years, mobile communication typified by mobile phones and the like has been remarkably advanced, and rapid miniaturization, thinning, and lightening are progressing. Magnetic components such as inductors and transformers are also required to be miniaturized and to have higher frequencies with an increase in operating frequency.

In a conventional high-frequency amplifier circuit, an air-core spiral coil formed only by wiring is used as an inductor for a tuning circuit or a choke coil for DC current supply. However, due to the air core structure, a large mounting area is required, and MMIC (Monolithic Microwave Integ
rated Circuit, monolithic microwave integrated circuit)
It is difficult to reduce the size of integrated circuits such as the above. In addition, there is a disadvantage that the resistance component increases due to an increase in the length of the wiring constituting the inductor, a voltage drop occurs, and power consumption increases. Further, since the magnetic flux is distributed over a wide range, the magnetic flux easily interferes with other elements. For this reason, it is necessary to increase the interval between other elements during mounting, which hinders miniaturization of electronic devices,
It is also a factor that reduces the degree of freedom in design and design.

On the other hand, magnetic materials conventionally used as magnetic cores of inductors include oxide magnetic materials such as Ni—Zn—Cu ferrite and Mn—Zn ferrite used in multilayer chip inductors. And metal magnetic materials such as Permalloy and Sendust. Of these, ferrite is an oxide and has a small saturation magnetization.
Therefore, the natural resonance frequency is low, and it is difficult to use it in a high frequency band. Metallic magnetic materials are not suitable for practical use because of their low resistivity and high eddy current loss in the high frequency band. Further, in a thin film inductor using a magnetic thin film, a magnetic thin film tends to be arranged near a wiring in order to increase inductance, but in such a case, in a thin film inductor using a metal magnetic material, a floating capacitance is caused. Loss due to circuit resonance will be induced.

[0005] As described above, the conventional magnetic, low resonant frequency, since the eddy current loss is large, GHz ⁽¹⁰ 9 H
It is not suitable as a magnetic core material of an inductor used in the high frequency band of z). Therefore, no attempt has been made to use these magnetic thin films for inductors used in a high frequency band to reduce the size and the frequency, and the large area occupied by the inductor hinders the miniaturization of integrated circuits. Has not been resolved. Further, when the capacitance and the inductance are formed close to each other and used in the GHz band, interference occurs between them. In order to eliminate such inconveniences, it is necessary to take measures to reduce interference.

The present invention focuses on the above points,
To provide a thin-film inductor capable of reducing the mounting area and achieving high efficiency by effectively utilizing magnetic flux, and reducing interference with nearby components, and an electronic device using the same. That is the purpose.

[0007]

In order to achieve the above object, the present invention provides a thin film inductor formed by using a granular film in which magnetic particles are wrapped in an insulator, and formed on a substrate via at least an insulating layer. In addition, a plurality of planar coils formed in a spiral shape by a conductor pattern are laminated via an insulating film, and a laminated coil connected between the plurality of planar coils, and at least a main surface above or below the laminated coil. On the other hand, there is provided a magnetic thin film provided on the one side via the insulating film and made of the granular film.

[0008] One of the main modes is that the laminated coil is
The conductor patterns of the plurality of planar coils are stacked so as to substantially match in the stacking direction.
Another embodiment is characterized in that the magnetic particles are a non-oxidized magnetic metal. Still another embodiment is characterized in that an antioxidant film for preventing oxidation of the non-oxidized magnetic metal is formed. Still another embodiment is characterized in that the magnetic thin film is formed of a laminated magnetic film in which a magnetic layer of a granular film in which the magnetic particles are wrapped in the insulator and an insulating layer are alternately stacked.

An electronic apparatus according to the present invention is characterized by using any one of the above-described thin film inductors. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

[0010]

<Embodiment 1> An embodiment of the present invention will be described in detail below. FIG. 1 shows the structure of the thin-film inductor of Embodiment 1, and FIG. 1A is an exploded perspective view showing a two-layer structure of the coil.
FIG. 1B is a main cross-sectional view of the present embodiment, and corresponds to a state in which the cross section of FIG. 1A taken along line # A- # A is viewed in the direction of the arrow.

First, the basic structure of the present embodiment will be described with reference to FIG. In FIG. 1B, the thin-film inductor 10 has a lower magnetic thin film 18 formed on a substrate 12 via an interlayer insulating film 16, and a first magnetic thin film 18 on the magnetic thin film 18 via an interlayer insulating film 20. The layer conductor pattern 22 is formed. A second-layer conductor pattern 28 is formed on the first-layer conductor pattern 22 with an interlayer insulating film 26 interposed therebetween. An upper magnetic thin film 34 is formed on the second layer conductor pattern 28 with an interlayer insulating film 32 interposed therebetween. That is, the structure is such that a spiral planar coil is sandwiched between an insulating film and a magnetic thin film.

As the substrate 12, for example, Si or the like is used. As the interlayer insulating films 16, 20, 26, 32, various substrates having a low dielectric constant may be used. It is suitable. Lower magnetic thin film 1
The upper magnetic thin film 8 and the upper magnetic thin film 34 are made of, for example, CoFeSiO, and are formed of a granular thin film in which an insulator (in this case, SiO ₂ ) and magnetic particles such as metal (in this case, CoFe) are separated and coexist.

As the granular thin film, a high saturation magnetic
, Low coercivity, low saturation magnetostriction, and high electrical resistivity
In addition, nanoscale (n
m, 10 ^-9) Order of nano-granular magnetic thin film
It is suitable. FIG. 8 (A) shows the state of a granular magnetic thin film.
Are shown and the SiO₂In the insulator 100,
Magnetic particles 102 made of a CoFe alloy are scattered. Another
In other words, it is insulated at the grain boundaries so as to enclose the magnetic particles 102.
The structure has an edge 100.

The thickness Di of the insulator 100 (the magnetic particles 102
Is smaller than 0.5 nm (5 °), the electrical resistivity decreases and the eddy current loss increases, and as a result, it is not suitable for practical use. On the other hand, insulator 1
When the thickness Di of No. 00 is larger than 1.5 nm (15 °), the exchange interaction between the magnetic particles 102 becomes small, so that the soft magnetic characteristics deteriorate. Therefore, the insulator 10
The thickness Di of 0 is preferably in the range of 0.5 nm to 1.5 nm. In particular, from the viewpoint of optimizing the magnetic permeability, the thickness Di of the insulator 100 is 0.8 nm to 1.2 n.
The range of m is more preferred. The particle diameter Dp of the magnetic particles 102 is, for example, about 10 nm (100 °).

Such a CoFeAlO granular magnetic thin film is formed by using a dual simultaneous non-reactive sputtering method using a CoFe alloy target and a SiO ₂ target so that no oxygen flows during the film formation. A rare gas such as argon is used as a sputtering gas, and a silicon single crystal is used as a substrate to form a film at room temperature.

FIG. 8B shows the measurement results of the frequency characteristics of the magnetic permeability measured by the one-turn coil method for the CoFeSiO nano-granular magnetic thin film sample among the samples prepared as described above. I have. The horizontal axis in the figure is frequency, and the vertical axis is magnetic permeability. Note that both axes are on a logarithmic scale. As shown in the figure, the value of the real part μ ′ of the magnetic permeability is about 300, which is a sufficiently large value for any measurement frequency. On the other hand, since the imaginary part μ ″ of the magnetic permeability is a very small value until the frequency reaches 2 GHz, it can be seen that the resonance frequency of the magnetic thin film of this example exceeds 2 GHz.

Returning to FIG. 1, the first-layer conductor pattern 22 and the second-layer conductor pattern 28 are formed in a spiral shape as shown in FIG. The upper and lower patterns are connected at 22A and 28A. The upper and lower conductor patterns do not necessarily have to coincide in the laminating direction, but are preferably formed to overlap with each other so that the effect of confining the magnetic flux is enhanced. As such a conductor pattern, a metal having a low electric resistance is suitable. For example, aluminum is used, but another metal such as copper may be used.

Next, with reference to FIGS. 2 and 3, an example of a method of manufacturing the thin film inductor 10 configured as described above will be described. 2 and 3 show a thin film inductor 1 according to the present embodiment.
0 is a view showing a manufacturing process 0; FIG. First, as shown in FIG. 2A, a polyimide to be the interlayer insulating film 16 is applied on the Si substrate 12 by an appropriate method such as a spin coating method.

Next, as shown in FIG. 2B, a pattern is formed by applying a lift-off resist 38 on the interlayer insulating film 16, and a nano-granular film is sputtered. Then, after removing the resist 38, a pattern of the lower magnetic thin film 18 is formed as shown in FIG. Thereafter, as shown in FIG. 3D, an interlayer insulating layer 20 of polyimide is formed again on the lower magnetic thin film 18 by an appropriate method such as spin coating. Next, as shown in FIG. 1E, Al is vapor-deposited on the entire surface as a conductor, and dry etching is performed by RIE using a photoresist 40 as a mask, thereby forming a spiral first layer as shown in FIG. The conductor pattern 22 is formed. The first layer conductor pattern 22
Is a connecting portion 22A connected to a second-layer conductor pattern 28 described later, and an outer end is a leading portion 24 for leading out to the outside.

Thereafter, as shown in FIG. 3A, a polyimide, which is an interlayer insulating layer 26, is applied on the first layer conductive pattern 22 by the above-described method. Interlayer insulation layer 2
6, a hole for exposing the connection portion 22A of the first-layer conductor pattern 22 is formed at a substantially central position.
A hole for exposing the lead portion 24 is formed at a position corresponding to the one lead portion 24 of the thin-film inductor 10 at the edge. Further, a surface flattening process is performed as necessary. In the present embodiment, since Al is used as the conductor pattern, it is not necessary to perform a planarization process. However, for example, when copper is used, the interlayer insulating film 26 having a certain thickness is formed and then planarized. It is preferable to carry out a chemical treatment.

After forming the first layer portion by the above procedure, and then performing thermosetting, the second layer portion is formed by the following procedure. As shown in FIG. 3B, Al for the second-layer conductor pattern 28 is vapor-deposited on the entire surface, dry-etched by RIE using the photoresist 42 as a mask, and the second layer as shown in FIG. The conductor pattern 28 is formed. As shown in FIG. 1A, the second-layer conductor pattern 28 is also a spiral-shaped planar coil, and a connection portion 28A for connecting to the first-layer conductor pattern 22 is provided at an end on the center side. Is formed. The other end portion of the thin-film inductor is formed at the outer end. At this time, since a contact hole is formed substantially at the center of the interlayer insulating film 26, the first hole is formed through the hole.
Connection portions 22A and 28A of the conductor pattern of the layer and the second layer
Is connected.

Next, as shown in FIG.
On the layer conductor pattern 28, polyimide to be the interlayer insulating layer 32 is applied by an appropriate method, and the upper part of the inductor is flattened. After applying a lift-off resist (not shown) on the flat surface to form a pattern, a granular thin film is formed by a sputtering method or the like. Thereby, the upper magnetic thin film 34 shown in FIG.

The thin-film inductor 10 formed as described above is connected to the first-layer conductor pattern 22 and the second-layer conductor pattern 2 via one lead 24 and the other lead 30.
When electricity is supplied to 8, the inductor 8 acts as an inductor because of the spiral shape. The magnetic flux generated by this energization acts on the lower magnetic thin film 18 and the upper magnetic thin film 34, and an inductor having predetermined characteristics is obtained. In FIG. 1B, the magnetic flux distribution of the thin-film inductor 10 of the present embodiment is indicated by arrows. As shown in the figure, the upper and lower magnetic thin films 18 and 3
Since the magnetic flux path 4 serves as a magnetic flux path, there is no magnetic flux leakage and the efficiency is high.

As described above, according to the present embodiment, the CoF
Since the lower magnetic thin film 18 and the upper magnetic thin film 34 made of the eSiO granular thin film are mounted on the upper and lower main surfaces of the spiral coil, it is possible to obtain a larger inductance value than before even though the wiring length is the same. In other words, since an inductance value larger than that of a conventional inductor can be obtained in the same area, the area occupied by the inductor can be reduced. Further, the series resistance of the choke inductor, which reduces the efficiency of the transistor by reducing the wiring length, can be reduced. Further, since the magnetic flux is concentrated in the magnetic thin films 18 and 34, the leakage of the magnetic flux to the outside is suppressed, the efficiency of the inductor can be improved, and the degree of freedom of design at the time of mounting can be increased.

Further, the thin-film inductor 10 of the present embodiment
Are the first layer conductor pattern 22 and the second layer conductor pattern 2
8 has a two-layer structure. With such a two-layer structure, the wiring length per unit inductance can be reduced as compared with the case of a single layer,
It is suitable for reducing the occupied area and suppressing the series resistance value. In addition, since the conductor patterns of the upper and lower wirings are laminated so as to match in the laminating direction, the effect of confining magnetic flux is improved.

Next, an example of high-frequency characteristics of the present embodiment will be described with reference to FIGS. According to the manufacturing method of the above-described embodiment, the thin-film inductors shown in FIGS. FIG. 4A is an air core type for comparison, and FIG.
FIG. 3C is a cross-sectional view of a sample of a thin-film inductor of the lower wiring type, FIG. 4C is a closed magnetic circuit type, and FIG. The impedance of each sample was measured using a network analyzer, the inductance value and the Q value were calculated, and the high-frequency characteristics were evaluated. 5A and 5B are diagrams showing the frequency characteristics of the inductance value and the Q value of a thin film inductor prepared as a sample. FIG. 5A shows an air core type for comparison, FIG. FIG. 11C shows the characteristics of the thin film inductor of the upper wiring type, FIG. 10D shows the characteristics of the closed magnetic circuit type, and FIG. 11E shows the characteristics of the upper and lower loading type thin film inductor. In the figure, the horizontal axis represents the frequency, the left vertical axis represents the inductance value, and the right vertical axis represents the Q value. The horizontal axis is a logarithmic scale, and “E” represents a power of 10 on both the horizontal axis and the vertical axis. For example, “E-09” becomes “10
^-9 ". The measured sample has a conductor pattern width of 10
μm, conductor pattern interval = 10 μm, number of conductor pattern turns = 5, and the total of the first layer and the second layer is 10 turns.

FIG. 6 shows each sample of the upper or lower loading structure and the upper and lower loading structure when the number of turns of the first layer conductor pattern and the second layer conductor pattern is 3 to 5, respectively, at 1 GHz. The increase rate of the inductance and the decrease rate of the resistance value per unit inductance are shown in comparison with the sample of the air-core type thin film inductor.

As shown in these figures, each of the samples loaded with the magnetic thin films shown in FIGS. 4B to 4E is different from the air-core type thin film inductor shown in FIG. In all cases, the inductance value is higher in the low frequency band than in the air core structure. For example, by adopting a structure in which a magnetic thin film is loaded on the lower or upper part, about 25%
It can be seen that the inductance value has increased to some extent. Further, by loading the magnetic thin film on the upper and lower sides, about 70% of the air-core structure in the low frequency band and the high frequency band (2
(GHz), the inductance value increases by about 30%. From these results, it can be confirmed that the magnetic thin film works effectively.

Further, comparing FIGS. 4D and 4E,
Both have almost the same characteristics. From this, it is understood that the granular magnetic thin film of the present embodiment is very effective in confining magnetic flux. On the other hand, a thin film inductor loaded with a magnetic thin film as described above tends to have a lower Q value than an air-core structure. However, since a magnetic thin film having a laminated structure is used, the resistivity is large. The degree of the decrease is not large.

It is considered that such an increase in the inductance value is due to the effect of confining the magnetic flux by the magnetic thin film. From these results, the resonance frequency of the magnetic thin film is at least 2 GHz at a low estimate, and
It is considered that sufficient magnetic characteristics can be obtained in a high frequency band of Hz.

As shown in FIG. 6, by loading a magnetic thin film on one of the upper, lower and upper and lower sides,
It can be seen that the resistance value per unit inductance is reduced by about 45%, which is effective in reducing the series resistance.
By reducing the series resistance in this way, it is possible to prevent an increase in power consumption due to a voltage drop. From the above results, it can be seen that the wiring length for obtaining the same inductance value is shortened, and the area occupied by the choke inductor can be reduced.

Next, FIG. 7 shows changes in the inductance value and Q value when the magnetic permeability, low efficiency, and structure (distance between the inductor and the magnetic thin film) of the magnetic thin film are changed. Specifically, when the magnetic permeability of the magnetic thin film is 300, the resistivity is 1.1 × 10 ⁻⁶ S / m, and the distance (t in FIG. 1B) between the magnetic thin film and the inductor is changed. The frequency characteristics of the inductance value and the Q value are shown for both the electromagnetic field simulation and the actual measurement. Also in this figure, the horizontal axis is frequency, the left vertical axis is inductance value, the right vertical axis is Q value, and the horizontal axis is logarithmic scale.

As shown in the figure, according to the result of the electromagnetic field simulation, as the interlayer distance t increases,
Although both the inductance value and the Q value are large,
It is saturated at about 15 μm. From this point, it is understood that the optimization of the arrangement of the magnetic thin film and the wiring is effective for improving the characteristics. Further, since the characteristics change depending on the resistivity of the magnetic thin film, the characteristics can be improved by using a magnetic thin film having a higher resistivity. Furthermore,
Since the fine processing of the magnetic thin film has the same effect as the increase in the resistivity, the parasitic component can be reduced by miniaturizing the magnetic thin film, so that an improvement in characteristics can be expected.

<Second Embodiment> Next, a second embodiment will be described. In the second embodiment, as shown in FIG. 9 (A), oxidation preventing films 110 and 11
2 are provided. As the lower magnetic thin film 18, as described above, for example, a granular film in which a magnetic metal is not oxidized is used. However, if the vacuum is broken after the lower magnetic thin film 18 is formed, the magnetic metal of the lower magnetic thin film 18 combines with oxygen and moisture in the air to be oxidized, thereby lowering the saturation magnetization and deteriorating the magnetic characteristics as a whole. Resulting in. The treatment of heating the lower magnetic thin film 18 also promotes oxidation of the magnetic metal.

Therefore, in the present embodiment, the lower magnetic thin film 18
By forming antioxidant films 110 and 112 on the front and back of
The oxidation of the magnetic metal in the lower magnetic thin film 18 is prevented. As the antioxidant films 110 and 112, for example, an Al ₂ O ₃ film, a SiO ₂ film, or the like is preferable.

In the illustrated example, the antioxidant film is provided on the front and back of the lower magnetic thin film 18. However, the antioxidant film may be formed only on one of the surfaces, particularly on the surface which is easily exposed to oxygen. The same applies to the upper magnetic thin film 34.

Third Embodiment Next, a third embodiment of the present invention will be described. In Embodiments 1 and 2 described above, a granular magnetic thin film having a single-layer structure has been described. In this embodiment, a magnetic layer and an insulating layer are stacked. As shown in FIG. 9B, the laminated magnetic film 50 includes a magnetic layer 52 made of a granular thin film in which an insulator 58 and magnetic particles (non-oxidized magnetic particles) 56 of non-oxidized metal or the like are separated and coexist. It has a laminated structure in which a plurality of insulating layers 54 made of materials or the like are alternately laminated. An antioxidant film 60 is formed on each of the front and back surfaces. Antioxidant film 60
The insulator 58 may be formed relatively thick. Of course, also in the present embodiment, the antioxidant film 60
May be provided on both the front and back sides of the laminated film as shown in the figure, or may be provided only on one of the surfaces, particularly on the surface side that comes into contact with the outside air.

The magnetic layer 52 of the laminated magnetic film 50 is formed of, for example, a CoFeAlO film.
Is formed of, for example, an Al ₂ O ₃ film. An example of the manufacturing method is as follows.
oFe alloy target (Co: Fe = 80: 20at%)
(Atomic%)) and an Al ₂ O ₃ target. Then, a Si substrate is prepared, and sputtering is performed using the targets alternately to form a CoFeAlO film and an A on the substrate.
A stacked film (thickness: 0.5 μm) of an l ₂ O ₃ film is formed. As the insulating layer 54, a SiO ₂ film may be used.

According to the laminated magnetic film 50 of the present embodiment, since the insulating layer 54 is introduced, the electric resistance increases, and the eddy current loss is reduced. In addition, since the growth of the magnetic particles 56 is hindered by the insulating layer 54 to be finer, the grain boundary density increases, the electric resistance increases, the crystal magnetic anisotropy is reduced, and the soft magnetic characteristics are improved. Of course, the laminated magnetic film 50
Has a resonance frequency of 2 GHz or more, and can be sufficiently used even in a high frequency band.

<Other Embodiments> The present invention has many embodiments, and various modifications can be made based on the above disclosure. For example, the following is also included. (1) The materials of the substrate, the insulating film, the magnetic thin film, and the wiring of the above-described embodiment are merely examples, and can be appropriately changed so as to achieve the same effect. (2) The manufacturing process described in the above embodiment is also an example, and various known methods may be applied. (3) In the above-described embodiment, the electrodes are drawn from the outermost side of the spiral wiring. For example, the first layer may have a fixed pattern drawn from the outermost side, and the second layer may be drawn from an appropriate position. By doing so, the L value (inductance value) of the inductor may be adjusted. According to the present invention, as a method of adjusting the L value, not only the length of the coil conductor pattern is changed, but also the degree of overlap between the upper and lower coil conductor patterns, the thickness of the insulating layer is changed, and the characteristics of the magnetic thin film are changed. It is also possible to adjust the area, the thickness, the number of layers, the material, and the like, and the coarse adjustment and the fine adjustment may be performed by different methods. (4) In the above embodiment, the wiring has a two-layer structure. However, a multilayer structure may be used if necessary. (5) The thin film inductor of the present invention may be used as a component alone or may be used in an integrated circuit. Further, the present invention is applicable to various electronic devices such as a mobile phone.

[0041]

As described above, according to the present invention,
The following effects can be obtained. (1) Since the magnetic thin film is loaded on at least one of the upper and lower surfaces of the spiral inductor, the inductance value per unit wiring length can be increased. As a result, the wiring length can be reduced, the mounting area or the occupied area can be reduced, and the series resistance can be reduced to suppress an increase in power consumption. Further, since the magnetic flux is concentrated in the magnetic thin film, the leakage of the magnetic flux to the outside is suppressed, and the efficiency as an inductance element can be increased. In addition, magnetic interference with adjacent components is reduced. (2) Since an inductor is formed by stacking a plurality of layers of planar coils, the inductance value per unit wiring length is further increased and the leakage of magnetic flux to the outside is suppressed as compared with the case of a single layer structure. The effect becomes higher.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a thin-film inductor according to a first embodiment of the present invention.

FIG. 2 is a view showing an example of a manufacturing process of the above embodiment.

FIG. 3 is a view showing an example of a manufacturing process of the above embodiment.

FIG. 4 is a main cross-sectional view of an inductor loaded with a magnetic thin film according to the embodiment and an inductor having an air-core structure.

FIG. 5 is a diagram showing an example of frequency characteristics of inductance and Q value of an inductor loaded with a magnetic thin film of the embodiment and an inductor having an air-core structure.

FIG. 6 is a diagram showing an increase rate of an inductance and a decrease rate of a resistance value per unit inductance as compared with the air-core structure of the embodiment.

FIG. 7 is a diagram illustrating an example of an electromagnetic field simulation of the inductance and the Q value of a thin-film inductor.

FIG. 8 is a diagram showing an example of a granular film. (A) is a figure which shows a structure, (B) is a figure which shows the frequency characteristic example of magnetic permeability.

FIG. 9 is a diagram showing magnetic thin films according to Embodiments 2 and 3 of the present invention.

[Explanation of symbols]

10 ... Thin film inductor 12 ... substrate 14 Conductor layer 16, 20, 26, 32 ... interlayer insulating film 18 Lower magnetic thin film (granular thin film) 22. 1st layer conductor pattern 22A, 28A ... connection part 24, 30 ... drawer 28: Second layer conductor pattern 34 Upper magnetic thin film (granular thin film) 38-42 ... Resist 50 ... Laminated magnetic film 52 ... magnetic layer 54 ... insulating layer 56 ... magnetic particles 58 ... insulator 60: antioxidant film 100 ... insulator 102 ... magnetic particles 110, 112 ... antioxidant film

Continuation of front page    (72) Inventor Kazuyoshi Kobayashi             6-16-20 Ueno, Taito-ku, Tokyo Taiyo Invitation             Den Co., Ltd. (72) Inventor Kenichi Ota             6-16-20 Ueno, Taito-ku, Tokyo Taiyo Invitation             Den Co., Ltd. (72) Inventor Masayuki Fujimoto             6-16-20 Ueno, Taito-ku, Tokyo Taiyo Invitation             Den Co., Ltd. F-term (reference) 5E070 AA01 CB12

Claims (6)

[Claims] 1. A thin-film inductor formed on a substrate through at least an insulating layer using a granular film in which magnetic particles are wrapped in an insulator, wherein the planar coil is formed in a spiral shape with a conductor pattern. A plurality of stacked coils connected to each other through a plurality of planar coils via an insulating film, and provided on at least one of the upper and lower main surfaces of the stacked coils via the insulating film, A thin film inductor comprising a magnetic thin film made of a film. 2. The thin-film inductor according to claim 1, wherein the laminated coils are laminated so that the conductor patterns of the plurality of planar coils substantially match in the laminating direction. 3. The thin film inductor according to claim 1, wherein the magnetic particles are a non-oxidized magnetic metal. 4. The thin film inductor according to claim 3, wherein an antioxidant film for preventing the non-oxidized magnetic metal from being oxidized is formed. 5. The magnetic thin film according to claim 1, wherein the magnetic thin film is formed by a laminated magnetic film in which a magnetic layer of a granular film in which the magnetic particles are wrapped in the insulator and an insulating layer are alternately laminated. 5. The thin film inductor according to any one of 4. 6. An electronic device using the thin-film inductor according to claim 1.