JP2022154553A - inductor - Google Patents

Abstract

To provide an inductor with large Q values in a frequency band from 100 MHz to hundreds of MHz.SOLUTION: In a planar spiral inductor, a first magnetic unit 10, a magnetic composite material inter-coil filling 20 in which a magnetic composite material obtained by combining magnetic fine particles and an insulating material is filled between wires of a coil 21, and a second magnetic unit 30 are laminated in this order. The first magnetic unit 10 and the second magnetic unit 30 are formed by laminating two layers of magnetic anisotropic films 11, 12, 31, 32 having different easy magnetization directions with insulating layers 13, 33 interposed therebetween, and has magnetically isotropic in the film plane.SELECTED DRAWING: Figure 2

Description

The present invention relates to inductors, and more particularly to planar spiral inductors.

Many electronic devices have switching power supplies. By increasing the switching frequency through the use of GaN power devices, etc., inductor elements and capacitors in power supplies can be made smaller and lighter, and they are particularly suitable for mobile electronic equipment and mobility.

Planar spiral inductors are often used as inductors for high-frequency circuits from the viewpoint of miniaturization and integration. In the future, it is expected that a switching power supply with a frequency of several hundred MHz using a power inductor with a magnetic core will be implemented. However, a low-loss power inductor compatible with a switching power supply of several hundred MHz has not yet been proposed.

In Patent Document 1, the inventor of the present application has proposed a technique for suppressing the proximity effect, which is a problem when using inductors at high frequencies. This technology fills the space between the coils of the inductor with a magnetic fine particle composite material that has low iron loss even at high frequencies, suppressing the proximity effect, thereby reducing the equivalent series resistance Rs and increasing the Q value (ωL/Rs). ing.

Also disclosed is a planar inductor having a laminated structure in which insulating layers are formed with a planar coil sandwiched between the upper and lower sides, and magnetic films whose magnetization (easy axis of magnetization) directions are perpendicular to each other are laminated on the upper and lower surfaces of the insulating layers. (See, for example, Patent Document 2).

Japanese Patent No. 6486614 JP-A-4-363006

In the technique disclosed in Patent Document 1, the equivalent series resistance Rs is reduced to increase the Q value. There is However, it was difficult to increase the inductance L with the conventional technology.

In addition, in the technology disclosed in Patent Document 2, etc., in the high frequency range of 100 MHz to several hundred MHz, loss due to eddy currents that occur in proportion to the square of the frequency and in inverse proportion to the electrical resistivity is a particular problem. There was a limit to increasing the value.

An object of the present invention is to provide an inductor having a large Q value in a high frequency band from 100 MHz to several hundred MHz.

The inductor of the present invention comprises a first magnetic unit, a magnetic composite inter-coil filler filled with a magnetic composite material obtained by combining magnetic fine particles and an insulating material, and a second magnetic unit in this order. In the laminated planar spiral inductor, each of the first magnetic unit and the second magnetic unit includes two layers of in-plane uniaxial magnetic anisotropic films having different easy magnetization directions, sandwiching an insulating layer. and is magnetically isotropic in the film plane.

According to the inductor of the present invention, the magnetic composite inter-coil filler, in which the magnetic composite material obtained by combining the magnetic fine particles and the insulating material is filled between the coil lines, is magnetically isotropic in the film plane. It is sandwiched by a first magnetic unit and a second magnetic unit. The first and second magnetic units have a high specific resistance in a high frequency band of 100 MHz to several hundred MHz compared to the laminated body of the magnetic film and the insulating layer disclosed in Patent Document 2 and the like. , the loss due to the occurrence of leakage current can be suppressed. This makes it possible to obtain an inductor having a large Q value in the frequency band of 100 MHz to several hundred MHz compared to the techniques described in Patent Documents 1 and 2 above.

In the inductor of the present invention, for example, each of the two in-plane uniaxial magnetic anisotropic films is made of a nanogranular film.

In the inductor of the present invention, the direction of easy magnetization of one of the two layers of in-plane uniaxial magnetic anisotropic films and the two layers of in-plane uniaxial magnetic anisotropy films It is preferable that the direction of easy magnetization of the other in-plane uniaxial magnetic anisotropic film is orthogonal.

In this case, leakage magnetic flux that can occur in the direction of easy magnetization of one of the in-plane uniaxial magnetic anisotropic films of the first or second magnetic unit is prevented from leaking to the outside through the other in-plane uniaxial magnetic anisotropic film. can be suppressed. This makes it possible to further improve the Q value.

In the inductor of the present invention, for example, the one in-plane uniaxial magnetic anisotropic film is (M1aM2b)1-X(L1cFd)X(M1: at least one selected from the group consisting of Fe, Co, and Ni, M2: at least one of Pd and Pt, L1: at least one selected from the group consisting of Li, Mg, Al, Ca, Sr, Ba, Gd and Y, 0.5≤a≤1.0, 0≤b≤0 .5 (a + b = 1), 0.2 ≤ c ≤ 0.4, 0.6 ≤ d ≤ 0.8 (c + d = 1), 0.15 ≤ X ≤ 0.55 (all atomic ratios )), and the other in-plane uniaxial magnetic anisotropic film is selected from the group consisting of (M3hM4i)1-Y(L2jFk)Y(M3: Fe, Co, and Ni at least one, M4: at least one of Pd and Pt, L2: at least one selected from the group consisting of Li, Mg, Al, Ca, Sr, Ba, Gd and Y, 0.5≤h≤1.0, 0≤ i ≤ 0.5 (h + i = 1), 0.2 ≤ j ≤ 0.4, 0.6 ≤ k ≤ 0.8 (j + k = 1), 0.15 ≤ Y ≤ 0.55 ( It is preferably a nanogranular film having a composition of all atomic ratios)).

In this case, it is possible to obtain the first and second magnetic units that have a high specific resistance in a high frequency band of 100 MHz to several hundred MHz and suppress leakage of the magnetic flux generated from the coil to the outside.

And the inductor of the present invention is suitable for use in the frequency band of 10 MHz to 10 Gz.

1 is a top view showing an inductor 100 according to an embodiment of the invention; FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1; FIG. 7 is a graph showing actual measurement results of frequency characteristics of complex relative permeability of the first and second magnetic units. 7 is a graph showing actual measurement results of frequency characteristics of loss factors of the first and second magnetic units. 5 is a graph showing analysis results of frequency characteristics of inductance L; 4 is a graph showing analysis results of frequency characteristics of an equivalent series resistance Rs; 7 is a graph showing analysis results of frequency characteristics of the Q value;

As shown in FIGS. 1 and 2, the inductor 100 according to the embodiment of the present invention is a planar type in which a first magnetic unit 10, a magnetic composite material inter-coil filler 20, and a second magnetic unit 30 are laminated in this order. is a spiral inductor.

The magnetic composite material inter-coil filler 20 is a magnetic composite material body in which a planar coil (winding wire) 21 and a magnetic composite material obtained by combining magnetic fine particles and an insulating material are filled between the wires of the coil 21. 22.

The magnetic composite inter-coil filler 20 is here a rectangular, more specifically square flat plate. Dimensions such as the thickness and the length of one side of the magnetic composite material inter-coil filler 20 may be appropriately determined according to the power supply to be used, the required inductance, and the like.

The coil 21 has a first ground wire portion 21a protruding upward at one end near the center thereof, and a second ground wire portion 21a protruding upward at the other end of the peripheral portion. and a portion 21b. These ground wire portions 21 a and 21 b are located inside the first magnetic unit 10 .

In the inductor 100, the central coil 21 acts as a planar spiral inductor, and the coil portion 21 is an inductor in a pure sense. The inductor 100 is an inductor in a broad sense and an inductor element.

The magnetic composite material body 22 is provided on the magnetic unit 10 so as to fill the space between the wires of the coil 21 in the thickness direction and also fill the outer region of the coil 21 in the thickness direction. The thickness of the coil portion 21 and the ground wire portions 21a and 21b of the embodiment is 8 μm, and the thickness of the magnetic composite material body 22 is also 8 μm. That is, the magnetic composite material body 22 is formed to have the same thickness as the coil portion 21 and the ground wire portions 21a and 21b, and is formed on the same surface as the coil portion 21 and the ground wire portions 21a and 21b.

The magnetic composite material forming the magnetic composite material body 22 is a magnetic composite material in which magnetic fine particles and an insulating material are mixed. A volume ratio of the magnetic fine particles and the insulating material is, for example, 10:90 to 80:20. More specifically, approximately spherical particles made of carbonyl iron powder with an average particle diameter of 1.1 μm are used as the Fe-based magnetic fine particles, and epoxy resin is used as the insulating material, and the carbonyl iron powder and the epoxy resin are used. A solvent may be added so that the volume ratio of 1 to 1 is 1:1, and used as an ink.

Then, the magnetic composite material composed of the carbonyl iron powder and the epoxy resin is supplied by a printing method so as to flatten the unevenness formed by the coil portion 21, and the space between the lines of the coil 21 is filled. After filling the outer region flat, in the atmosphere, for example, using a hot plate, heating at 120 ° C. for 5 minutes, using an electric furnace at 120 ° C. for 120 minutes, and heating at 140 ° C. for 180 minutes to form a magnetic composite material. The contained solvent is removed and the epoxy resin is completely cured to obtain the magnetic composite material 20 .

In order to prevent the surface of the coil 21 from being covered with the magnetic composite material, it is preferable to roughen the surface with sandpaper or the like, and then mirror-polish the surface to form the second magnetic unit 30 thereon. Although the high-frequency characteristics of the inductor are improved by not covering the surface of the coil 21 with the magnetic composite material, the surface of the coil 21 may be covered with the magnetic composite material depending on the application.

It is preferable to use Fe-based magnetic fine particles as the magnetic fine particles used in the magnetic composite material, since the Fe-based material has excellent magnetic properties and is easily available. Fe-based magnetic fine particles include Fe fine particles and Fe alloy fine particles. As magnetic fine particles, in addition to Fe-based magnetic fine particles, Co-based magnetic fine particles and Ni-based magnetic fine particles can be used. These fine particles also have the same effect as the Fe-based magnetic fine particles.

The reason why magnetic fine particles are used as the magnetic material for the magnetic composite material that fills the spaces between the wires of the coil 21 is that the induced current (eddy current) generated in the magnetic fine particles when external magnetic flux interlinks with the magnetic fine particles can be ignored. This is because the magnetic loss due to the induced current can be suppressed to an extremely low level.

The magnetic loss due to the induced current generated in the magnetic fine particles can be ignored because the particle size of the magnetic fine particles is small. Even if an induced current is generated in each magnetic fine particle, since the particles are small, the change in magnetic flux is followed and resistance loss does not occur. In order to utilize the effects of such particles, it is preferable to use magnetic fine particles as small as possible.

Magnetic fine particles such as Fe fine particles are spherical and have an average particle size of 0.1 μm to 20 μm, more preferably 0.5 μm to 5 μm. Although it depends on the material of the magnetic fine particles, if the magnetic fine particles have a particle size of 2 μm or less, they can be sufficiently used as the material of the magnetic composite material body 22 of the inductor used in the frequency band of 0.1 to 1 GHz. can. The magnetic microparticles are not limited to spherical ones, and may have other shapes such as elliptical spheres, or may have irregularities on the outer surface.

The first magnetic unit 10 and the second magnetic unit 30 are disk-shaped flat plates here. The diameters of the first magnetic unit 10 and the second magnetic unit 30 are determined according to the size of the magnetic composite inter-coil filler 20 . Note that the first magnetic unit 10 and the second magnetic unit 30 are not limited to disk-shaped flat plates.

The first magnetic unit 10 and the second magnetic unit 30 are shaped to include all the coils 21 when viewed from above. Moreover, it is preferable that the first magnetic unit 10 and the second magnetic unit 30 have the same size, particularly the same shape when viewed from above.

The first magnetic unit 10 includes a magnetic anisotropic film 11 having uniaxial magnetic anisotropy in the film plane and a magnetic anisotropic film 12 similarly having uniaxial magnetic anisotropy in the film plane. These magnetic anisotropic films 11 and 12 are laminated with an insulating layer 13 interposed therebetween so as not to be coupled. It is isotropic. The second magnetic unit 30 also includes a magnetic anisotropic film 31 having uniaxial magnetic anisotropy in the film plane and a magnetic anisotropic film 32 similarly having uniaxial magnetic anisotropy in the film plane. are stacked with an insulating layer 33 interposed therebetween so as not to be magnetically coupled. It is sex.

The magnetic anisotropic films 11 and 12 of the first magnetic unit 10 are both in-plane uniaxial magnetic anisotropic films and have a magnetic anisotropy constant _Ku1 . Both the films 31 and 32 are in-plane uniaxial magnetic anisotropy films and have a magnetic anisotropy constant _Ku2 . Here, in the first and second magnetic units 10 and 30, the direction of easy magnetization of one of the magnetic anisotropic films 11 and 31 and the direction of easy magnetization of the other magnetic anisotropic film 12 and 32 are orthogonal to each other. there is However, since the first magnetic unit 10 and the second magnetic unit 30 are not magnetically coupled, the directions of easy magnetization of the magnetic anisotropic film 12 and the adjacent magnetic anisotropic film 31 intersect other than orthogonally. may or may not intersect.

In these magnetic anisotropic films 11, 12, 31, and 32, when a high-frequency magnetic field H _ex of minute amplitude is applied in the direction of an angle θ in the film plane from the direction of easy magnetization of the magnetic anisotropic films 12 and 32, The magnetic permeability μ ₂ of the magnetic anisotropic films 12 and 32 is μ ₂ (θ)=M _s2 ×sin ² θ/2K _u2 . The magnetic permeability μ ₁ of the magnetic anisotropic films 11 and 31 whose easy magnetization direction is perpendicular to that of the magnetic anisotropic films 12 and 32 is μ ₁ (θ)=M _s1 ×sin ² (90−θ)/2K becomes _u1 . The magnetic permeability μ(θ) of the ferromagnetic thin film laminate is μ ₁ (θ)+μ ₂ (θ). M _s1 and M _s2 are the saturation magnetizations of the magnetic anisotropic films 11 and 31 and the magnetic anisotropic films 12 and 32, respectively.

In the first and second magnetic units 10 and 30, if the magnetic anisotropic films 11 and 31 on one side and the magnetic anisotropic films 12 and 32 on the other side have the same specifications, then M _s1 =M _s2 =M _s and K _u1 =K _u2 =K _u , in μ ₁ (θ)+μ ₂ (θ), the coefficient of the trigonometric function vanishes, resulting in M _s /2K _u and the incident angle of the high-frequency magnetic field H _ex Since the dependence on θ is eliminated and it becomes a constant, the distribution of magnetic permeability becomes completely isotropic in the film plane. On the other hand, if the specifications of the magnetic anisotropic films 11, 12, 31, and 32 do not match due to variations in the manufacturing process, and _Ku1 ≠ _Ku2 , or M _s1 ≠ M _s2 and _Ku1 ≠ _Ku2 , , the distribution of magnetic permeability breaks down from perfectly isotropic and becomes isotropic to the last, but since it becomes almost isotropic, it does not pose a big problem.

This principle itself is described in Non-Patent Document 1 (Y. Shimada, E. Sugawara, and H. Fujimori: “Initial permeability of composite anisotropy multilayer films”, Journal of Applied Physics, Vol. 76, No. 4, pp. 2395- 2398 (1994)) as an example.

In addition, in order to secure the thickness of the inductor 100 excluding the substrate 40, the magnetic anisotropic films 11, 12, 31, 32 in the first and second magnetic units 10, 30 are arranged in multiple stages, that is, the first Both the magnetic anisotropic films 11 and 12 in the magnetic unit 10 and the magnetic anisotropic films 31 and 32 in the second magnetic unit 30 may be multi-layered, such as four layers or six layers.

One of the magnetic anisotropic films 11 and 31 of the first and second magnetic units 10 and 30 is made of, for example, a nanogranular film, but it may be an in-plane uniaxial magnetic anisotropic film, which is made of a nanogranular film. is not limited to However, if the magnetic anisotropic films 11 and 31 are made of nano-granular films, they have the advantage that they have a high electrical resistivity and a magnetic permeability of up to several GHz, enabling magnetic resonance. In addition, in the technique described in Non-Patent Document 1, a metal magnetic thin film having a low specific resistance is used.

The magnetic anisotropic films 11 and 31 are (M1aM2b) _1-x (L1cFd) _x (M1: at least one selected from the group consisting of Fe, Co, and Ni; M2: at least one selected from Pd and Pt; L1: A nanogranular film having a composition of at least one selected from the group consisting of Li, Mg, Al, Ca, Sr, Ba, Gd and Y).

Specific examples of such nanogranular films include CoPd--CaF ₂ , CoPd--MgF ₂ , CoFePd--CaF ₂ , CoFe--CaF ₂ , CoFe--BaF ₂ and CoFe--MgF ₂ .

Further, a and b, which determine the ratio of the metal (magnetic) portion constituting the nanogranular films forming the magnetic anisotropic films 11 and 31, are 0.5≤a≤1.0 and 0≤b≤0.5. (a+b=1) is preferred. Similarly, c and d that determine the ratio of the metal L1 and F (fluorine) in the insulating portion constituting this nanogranular film are 0.2≤c≤0.4, 0.6≤d≤0.8 ( It is preferred that c+d=1). Furthermore, it is preferable that X, which determines the ratio of the metal portion and the insulating portion, satisfies 0.15≦X≦0.55 (all atomic ratios). These can efficiently achieve the object of the present invention.

Although the thickness of the magnetic anisotropic films 11 and 31 is not particularly limited, it is preferably 100 nm or less in the case of nanogranular films in order to obtain physical properties of high magnetic permeability.

Regarding the thickness dependence of the magnetic permeability of nanogranular films, see Non-Patent Document 2 (Mas. GHz Band High-Frequency Complex Permeability and Noise Suppression Effect of Laminated Films", Institute of Electrical Engineers of Japan Research Meeting Materials, pp.51-56, MAG-18-072/LD-18-045 (2018)).

The other magnetic anisotropic films 12 and 32 of the first and second magnetic units 10 and 30 are made of, for example, nanogranular films, but any in-plane uniaxial magnetic anisotropic films may be used and made of nanogranular films. is not limited to The magnetic anisotropic films 12 and 32 are (M3hM4i) _1-Y (L2jFk) _Y (M3: at least one selected from the group consisting of Fe, Co, and Ni; M4: at least one selected from Pd and Pt; L1: A nanogranular film having a composition of at least one selected from the group consisting of Li, Mg, Al, Ca, Sr, Ba, Gd and Y).

Specific examples of such nanogranular films include CoPd--CaF ₂ , CoPd--MgF ₂ , CoFePd--CaF ₂ , CoFe--CaF ₂ , CoFe--BaF ₂ and CoFe--MgF ₂ .

Further, h and i, which determine the ratio of the metal (magnetic) portion constituting the nanogranular films forming the magnetic anisotropic films 11 and 31, are 0.5≤h≤1.0 and 0≤i≤0.5. (h+i=1) is preferred. Similarly, j and k that determine the ratio of the metal L2 and F (fluorine) in the insulating portion constituting this nanogranular film are 0.2≤j≤0.4, 0.6≤k≤0.8 ( Preferably j+k=1). Furthermore, Y, which determines the ratio between the metal portion and the insulating portion, preferably satisfies 0.15≦Y≦0.55 (all atomic ratios). These can efficiently achieve the object of the present invention.

Although the thickness of the magnetic anisotropic films 12 and 32 is not particularly limited, it is preferably 100 nm or less in the case of nanogranular films in order to obtain physical properties of high magnetic permeability. In order to increase the permeance in the magnetic circuit of the inductor, or when it is necessary to increase the total cross-sectional area of the magnetic anisotropic film, the first and second magnetic units 10 and 30 are arranged in multiple stages as described above. can be

In the magnetic anisotropic films 11 and 12 of the first magnetic unit 10 or the magnetic anisotropic films 31 and 32 of the second magnetic unit 30, the nanogranular film may be a single layer film, but has a composition of L1cFd or L2jFk. A periodic multilayer structure with a thin insulating film may be formed. In this periodic multilayer structure, the directions of easy magnetization of the in-plane uniaxial anisotropy of the nanogranular films are all oriented in the same direction. The cycle is not particularly limited, and can be, for example, 2 to 400 cycles. In addition, in this embodiment, it is set as 5 cycles.

In addition, in order to realize the periodic multilayer structure of each of the magnetic anisotropic films 11, ₁₂ , 31 and 32, the composition of the thin insulating film for partitioning the nanogranular films includes _CaF2 , _MgF2 , BaF2, AlF ₃ , GdF ₃ and the like can be mentioned.

Moreover, as is clear from the above description, it is preferable that the nanogranular films constituting the magnetic anisotropic films 11, 12, 31, and 32 have the same component composition. In this case, for example, the same target can be used in the manufacturing method described below. Isotropic magnetic properties can be easily obtained.

The magnetization direction of one magnetic anisotropic film 11, 31 and the magnetization direction of the other magnetic anisotropic film 12, 32 are preferably perpendicular to each other. As a result, leakage magnetic flux that may occur in the in-plane easy magnetization direction of one of the magnetic anisotropic films 11 and 31 is suppressed by the other magnetic anisotropic film 12 and 32 from leaking to the outside. can be improved. The magnetization directions of the magnetic anisotropic films 11 and 31 on one side and the magnetization directions of the magnetic anisotropic films 12 and 32 on the other side need not be orthogonal, but are preferably not parallel.

The insulating layers 13 and 33 are located between the magnetic anisotropic films 11 and 12 of the first magnetic unit 10 and between the magnetic anisotropic films 31 and 32 of the first magnetic unit 10, respectively. , separates the magnetic coupling between the magnetic anisotropic films 11 and 31 on one side and the magnetic anisotropic films 12 and 32 on the other side.

The thickness of the insulating layers 13 and 33 is preferably, for example, 50 to 5000 nm, more preferably 100 to 1000 nm, depending on the thickness of the magnetic anisotropic films 11, 12, 31 and 32.

As described above, when the first and second magnetic units 10 and 30 are configured in multiple stages, the magnetic anisotropic films 11, 12, 31 and 32 which are vertically adjacent to each other should not be magnetically coupled. An insulating layer having a thickness equivalent to that of the insulating layers 13 and 33 must be provided.

Further, the insulating layers 13 and 33 can have any non-ferromagnetic insulating component composition as long as the magnetic anisotropic films 11 and 31 on one side and the magnetic anisotropic films 12 and 32 on the other side are magnetically separated from each other. However, since it also functions as a base film for the magnetic anisotropic films 12 and 32 located above the respective first and second magnetic units 10 and 30, the insulating portions of these magnetic anisotropic films 12 and 32 and It is preferred to have the same component composition.

The inductor 100 is formed by laminating a first magnetic unit 10, a magnetic composite material inter-coil filler 20, and a second magnetic unit 30 on a substrate 40 in this order. The first magnetic unit 10 and the second magnetic unit 30 are each formed on the underlying film 50 .

It is necessary to prevent electrical continuity between the coil 21 of the magnetic composite inter-coil filler 20 and the first magnetic unit 10 and the second magnetic unit 30 . For this reason, an insulating film 51 is provided between the magnetic composite material inter-coil filler 20 and the first magnetic unit 10 (between the magnetic composite material inter-coil filler 20 and the magnetic anisotropic film 12). If necessary, an insulating layer may be provided between the inter-coil filler 20 and the second magnetic unit 30 (between the magnetic composite inter-coil filler 20 and the base film 50).

The substrate 40 may have the same size as the magnetic units 10 and 30 or may be larger than the magnetic units 10 and 30 . Further, a plurality of sets of inductors 100 each including a first magnetic unit 10, a magnetic composite material inter-coil filler 20, and a second magnetic unit 30 are formed on a large substrate 40, and the substrate 40 is cut to obtain a plurality of inductors. of inductor 100 may be formed.

The substrate 40 can be composed of general-purpose substrates such as ceramics (glass, magnesia, zirconia, sapphire, etc.), silicon substrates, and the like. Also, instead of the substrate 40, an appropriate support may be used. Furthermore, a device made of resin such as polyimide may be used instead of the substrate 40 .

In addition, since the underlayer 50 is also the underlayer of the nanogranular film that constitutes the magnetic anisotropic films 11 and 31 of one of the first and second magnetic units 10 and 30, it is preferable that the magnetic portion or the insulating layer of this nanogranular film is used. It is preferred to have the same component composition as the part. However, if the component composition is the same as that of the magnetic portion of the nanogranular film, for example, if the ratio of the metal (magnetic) portion is large, the underlayer 50 will have ferromagnetism, and the underlayer will have ferromagnetism. It will have a magnetic effect in addition to the effect as Therefore, in this case, it is preferable to reduce the proportion of the metal (magnetic) portion so that the underlayer 50 does not become ferromagnetic.

Specifically, the base film 50 includes (M5pM6q)1-Z(L3rFs)Z(M5: at least one selected from the group consisting of Fe, Co, and Ni, M6: at least one selected from Pd and Pt, L3: Li , Mg, Al, Ca, Sr, Ba, Gd and Y). At this time, 0.5 ≤ p ≤ 1.0, 0 ≤ q ≤ 0.5 (p + q = 1), 0.2 ≤ r ≤ 0.4, 0.6 ≤ s ≤ 0.8 ( r+s=1) and 0.55≦Z≦1.00. When Z=1.00, the base film 50 is a single layer of L3rFs. The thickness of the base film 50 is preferably more than 0 nm and 500 nm or less, more preferably 10 nm to 100 nm.

Since the base film 50 has electrical insulation properties, the base film 50 of the second magnetic unit 30 can be used as an insulating film that prevents conduction between the coil 12 and the second magnetic unit 30 described above. As for the first magnetic unit 10, an insulating film 51 made of a nano-granular film having the same composition as the base film 50 is provided on the upper surface of the magnetic anisotropic film 12 to prevent conduction between the coil 12 and the first magnetic unit 10. ing.

As described above, according to the inductor 100, the nano-granular films of the first and second magnetic units 10 and 30 are compared with the laminated body of the magnetic film and the insulating layer disclosed in Patent Document 2 and the like. It has a high specific resistance in a high frequency band of 100 MHz to several hundred MHz, and suppresses leakage of the magnetic flux generated from the coil 21 to the outside. As a result, it is possible to suppress the loss due to the occurrence of leakage current, and compared to the techniques described in Patent Documents 1 and 2, it has a large Q value in the frequency band of 100 MHz to several hundred MHz. It becomes possible to obtain an inductor.

Hereinafter, an example of the inductor 100 according to the embodiment of the present invention was analyzed using electromagnetic field analysis software (“HFSS” manufactured by Ansoft Japan Co., Ltd.) using the three-dimensional finite element method.

The first magnetic unit 10 and the second magnetic unit 30 were assumed to be disk-shaped with a diameter of 800 μm and a thickness of 10 μm. The magnetic composite inter-coil filler 20 was assumed to be a square disk with a side of 1.0 mm and a thickness of 50 μm. It was assumed that the coil 21 had two turns and was a copper wire with a line width of 30 μm and a line spacing of 100 μm. The magnetic composite inter-coil filler 20 is composed of the carbonyl iron powder and the epoxy resin in a volume ratio of 1:1 using 10.3% by volume of HCl as a solvent so that the composite magnetic material 22 is placed between the coils 21 and between the coils 21 . After flatly filling the outer region of the magnetic composite material, it is heated in an electric furnace at 240 ° C for 6 hours in the atmosphere to remove the solvent contained in the magnetic composite material and completely harden the epoxy resin. It is.

Assuming that the magnetic anisotropic films 11, 12, 31, and 32 are made of Co35Fe65PdCaF nanogranulated films, the frequency characteristics of the complex relative permeability and the loss factor of the first magnetic unit 10 and the second magnetic unit 30 are shown in FIG. 3 and the actual measurement results shown in FIG. 4 were used.

The first magnetic unit 10 and the second magnetic unit 30 in the first example are not present, and an inductor composed only of the magnetic composite material inter-coil filler 20 is taken as a first comparative example. Comparative Example 2 is an air-core inductor in which the first magnetic unit 10 and the second magnetic unit 30 in Example 1 are not present, and the portion occupied by the magnetic composite material body 22 is a space. These comparative examples 1 and 2 were also analyzed in the same manner as the example. Comparative Example 1 corresponds to the technology described in Patent Document 1 above.

As shown in FIG. 5, the inductance L of the example is about 1.3 times greater than that of Comparative Example 1 and about 1.5 times greater than that of Comparative Example 2 over the entire range of frequency f from 100 MHz to 1000 MHz. rice field. This is considered to be the effect of adding the first magnetic unit 10 and the second magnetic unit 30 .

Further, as shown in FIG. 6, the equivalent series resistance Rs of the example becomes higher than that of the comparative examples 1 and 2 due to the influence of the iron loss of each magnetic material when the frequency f is about 200 MHz or higher. At 200 MHz or less, it is lower than in Comparative Examples 1 and 2 due to the reduced proximity effect and reduced copper loss.

As shown in FIG. 7, the Q value of the example is larger than that of Comparative Examples 1 and 2 when the frequency f is about 300 MHz or less, and when the frequency f is about 200 MHz, it is about 1.3 times that of Comparative Example 1. It was found to be approximately 1.5 times larger than in Comparative Example 2. It was also found that the Q value of the example is about 1.5 times that of Comparative Example 1 and about 1.8 times that of Comparative Example 2 when the frequency f is about 100 MHz.

Although several embodiments of the invention have been described above, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

10 First magnetic unit 11 One magnetic anisotropic film (in-plane uniaxial magnetic anisotropic film) 12 The other magnetic anisotropic film (in-plane uniaxial magnetic anisotropic film) 13 Insulating layer 20 Filler between magnetic composite material coils 21 Coil 22 Magnetic composite material body 30 Second magnetic unit 31 One magnetic anisotropic film (in-plane uniaxial magnetic anisotropy film), 32... The other magnetic anisotropic film (in-plane uniaxial magnetic anisotropic film), 33... Insulating layer, 40... Substrate, 50... Base film, 51... Insulating film, 100... Inductor.

Claims (5)

A planar type in which a first magnetic unit, a magnetic composite material inter-coil filling body in which a magnetic composite material composed of a composite of magnetic fine particles and an insulating material is filled between coil wires, and a second magnetic unit are laminated in this order. A spiral inductor,
Each of the first magnetic unit and the second magnetic unit is formed by stacking two layers of in-plane uniaxial magnetic anisotropic films having different easy magnetization directions with an insulating layer interposed therebetween. An inductor characterized by being tropic. 2. The inductor according to claim 1, wherein each of said two layers of in-plane uniaxial magnetic anisotropic films is a nanogranular film. The direction of easy magnetization of one of the two layers of in-plane uniaxial magnetic anisotropic films and the surface of the other of the two layers of in-plane uniaxial magnetic anisotropy films 3. The inductor according to claim 1, wherein the direction of easy magnetization of the inner uniaxial magnetic anisotropic film is orthogonal. The one in-plane uniaxial magnetic anisotropic film is (M1aM2b)1-X(L1cFd)X(M1: at least one selected from the group consisting of Fe, Co, and Ni; M2: at least one selected from Pd and Pt. , L1: at least one selected from the group consisting of Li, Mg, Al, Ca, Sr, Ba, Gd and Y; ), 0.2 ≤ c ≤ 0.4, 0.6 ≤ d ≤ 0.8 (c + d = 1), 0.15 ≤ X ≤ 0.55 (all atomic ratios). and
The other in-plane uniaxial magnetic anisotropic film is (M3hM4i)1-Y(L2jFk)Y(M3: at least one selected from the group consisting of Fe, Co, and Ni; M4: at least one selected from Pd and Pt. , L2: at least one selected from the group consisting of Li, Mg, Al, Ca, Sr, Ba, Gd and Y; ), 0.2≦j≦0.4, 0.6≦k≦0.8 (j+k=1), 0.15≦Y≦0.55 (all atomic ratios)). The inductor according to any one of claims 1 to 3, characterized in that: The inductor according to any one of claims 1 to 4, characterized in that it is used in a frequency band of 10MHz to 10Gz.

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