JPH1074626A - Thin magnetic element, its manufacture, and transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable introduction of magnetic flux generated by a coil pattern formed on at least one side of a base into a magnetic thin film with efficiency, by forming the magnetic thin film on the coil pattern so that the coil pattern will be covered. SOLUTION: A coil body (coil pattern) 22 is placed on both sides of a substrate (base) 21, and the exterior of the coil bodies 22 and the surface of the substrate around the coil bodies 22 are covered with a magnetic thin film 23. The coil bodies 22 are formed by forming a coil conductor 24 having a rectangular cross-section on the front side and the underside of the substrate 21 in a zigzag pattern. The substrate 21 is constituted of resin such as polyimide or an insulating, non-magnetic material such as ceramic. The magnetic thin film 23 is comprised of a special soft magnetic material having a high specific resistance, which is a composition of one or more elements selected from Fe, Co and Ni, a lanthanoid rare earth metal element, such as La and Ce, and element of Al and Si.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin magnetic element having a structure in which a coil pattern is formed on a base and a magnetic thin film is provided on the coil pattern, a method for manufacturing the same, and a transformer.

[0002]

2. Description of the Related Art Along with the miniaturization and high performance of a magnetic element, a soft magnetic material having a high magnetic permeability at a frequency of several hundred MHz or more, particularly a high saturation magnetic flux density of 5 kG or more, a high specific resistance, and a low specific resistance. A material having a coercive force is required. Among them, a transformer having a high specific resistance is particularly required. As a magnetic material having a high saturation magnetic flux density, Fe or an alloy containing Fe as a main component is widely known. However, when a magnetic film of these alloys is formed by a film forming technique such as a sputtering method, the saturation magnetic flux density is high. However, the coercive force was large and the specific resistance was small, and it was difficult to obtain good soft magnetic characteristics in a high frequency range. Further, ferrite, which is frequently used as a bulk material, cannot obtain excellent soft magnetic properties in a thin film state.

[0003]

One of the causes of a decrease in magnetic permeability at a high frequency is a loss due to the generation of an eddy current. In order to prevent eddy current loss, which is one of the causes of the decrease in the high-frequency magnetic permeability, it is desired to reduce the thickness and increase the resistance of the thin film. However, it is very difficult to increase the specific resistance while maintaining the magnetic characteristics, and the specific resistance of a soft alloy thin film such as a crystalline alloy such as Sendust or an amorphous alloy is as small as several tens to one hundred and several tens μΩcm, At least 5
There is a demand for a soft magnetic alloy having an increased specific resistance while securing a saturation magnetic flux density of kG (0.5 T) or more. When an alloy is obtained as a thin film, it is more difficult to obtain good soft magnetic properties due to the influence of magnetostriction and the like.

In the technical background having the problem of the soft magnetic thin film material described above, FIGS. 13 and 14 show an example of a planar coil having a structure capable of reducing the size and weight of a magnetic element.
As shown in FIG. 1, there is known an arrangement in which a coil conductor having a two-layer structure is arranged between upper and lower substrates 1 and 2. In the coil K of this example, a magnetic thin film 3 and an insulating film 4 are respectively laminated on opposing surfaces of upper and lower substrates 1 and 2, and both sides are placed on a flexible substrate 5 provided between the upper and lower insulating films 4 and 4. It has a structure in which coil conductors 6, 6 sandwiched between are provided. FIG.
FIG. 4 shows a plan view of the coil conductor 6. The coil conductor 6 of this embodiment is a coiled coil body 7 in which two coiled portions 6a are juxtaposed and connected by a connecting portion 6b. .

[0005] The coiled coil K having the above-described structure has an advantage of excellent high frequency characteristics. However, in order to manufacture the coil K, the magnetic thin films 3 and 4 are laminated on the substrates 1 and 2. Separately from these, a thick film-shaped coil body 7 is formed on both sides of the flexible substrate 5 by plating or screen printing.
It is necessary to manufacture a product formed with the above, and to manufacture it by positioning and bonding the substrates 1 and 2 so as to sandwich both sides of the flexible substrate 5 having the coil bodies 7 and 7. In addition, there is a problem in that the production and assembly takes a lot of time and the yield is likely to decrease. In the meander-shaped coil K, since the coil conductor 6 and the magnetic thin film 3 are separated via the insulating film 4, the coil conductor 6
There is a problem that the magnetic flux generated around the magnetic thin film does not effectively enter the magnetic thin film and the efficiency is reduced.

The present invention has been made in view of the above circumstances, has few components, is easy to assemble, can be manufactured entirely by a film forming apparatus, can be made thinner, and has a coil conductor periphery. It is an object of the present invention to provide a thin magnetic element capable of reducing the loss due to the generation of the eddy current, a method of manufacturing the thin magnetic element, and a transformer including the thin magnetic element.

[0007]

According to the present invention, there is provided a coil pattern formed on at least one surface of a substrate, and a magnetic thin film formed on the coil pattern so as to cover the coil pattern. It is provided with. In the above configuration, a magnetic thin film may be provided in contact with the coil pattern. Further, a magnetic thin film may be formed on the coil pattern via an insulating film,
In the above configuration, the coil pattern may be formed on the magnetic thin film formed on the base, and the coil conductor constituting the coil pattern may be surrounded by the magnetic thin film.

Next, in the above structure, a coil pattern is formed on both opposing surfaces of the base, a through hole is formed in the base between the coil patterns, and magnetic thin films on both sides of the base are connected via the through hole. A configuration may be used. Further, the planar shape of the coil pattern may be a meander type or a meander type. Next, it is preferable that the magnetic thin film formed on the coil pattern on the base is made flat. A magnetic layer for embedding the coil pattern around the coil pattern on the base may be provided, and the magnetic material of the magnetic layer may be different from the magnetic material of the magnetic thin film formed thereon. Further, the magnetic layer formed around the coil pattern on the substrate is made of a Ni—Fe alloy, Co—F
An alloy mainly composed of either an e-alloy or a Ni-Fe-Co alloy may be used. Further, the magnetic layer formed around the coil pattern on the base may be formed by plating. Next, the planar shape of the coil pattern may be a spiral type.

Next, in the above structure, Fe, Co, N
i, a fine crystal phase having an average crystal grain size of 30 nm or less and a lanthanoid rare earth element (La, Ce, Pr, Nd, Pm, Sm, Eu, G)
d, Tb, Dy, Ho, Er, Tm, Lu, one or more of them), Ti, Zr, Hf, Ta, Nb,
One or more elements M and O selected from Mo and W
Or a magnetic thin film composed of an amorphous phase containing a compound of the elements M and N as a main component may be used for part or all of the magnetic core.

On the other hand, one or more selected from Fe, Co, and Ni are used as the element A, and the rare earth metal elements (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd,
Tb, Dy, Ho, Er, Tm, Lu), and at least one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, and W And Al, Si, Cr, Pt, Ru, Rh, P
When at least one or two or more elements selected from the group consisting of d and Ir are M ′ and one or two of O and N are L, A _a M _b M ′ _C L _d The magnetic thin film may be made of a soft magnetic material represented by the following composition formula. Next, a transformer may be provided with the thin magnetic elements having the various structures.

According to the manufacturing method of the present invention, a coil conductor is formed on a substrate, the top surface and the peripheral surface of the coil conductor are covered with an insulating film, and the substrate is etched after covering the outer surface of the insulating film with a resist. A through hole is formed in the portion of the substrate that is not covered with the resist, and then the resist is removed to obtain a substrate with a coil conductor and a through hole covered with an insulating film. The magnetic thin film is formed so as to cover the back surface, the insulating film outside the coil conductor, and the through hole. When this manufacturing method is performed, a magnetic thin film made of a soft magnetic material having the above composition can be used.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a first embodiment according to the present invention. In this embodiment, a thin magnetic element 20 is provided on both sides of a substrate (base) 21 having a sectional structure shown in FIG. -Shaped coil body 2 showing
The magnetic thin film 23 covers the outer surface of the coil body 22 and the surface of the substrate around the coil body 22. The coil body (coil pattern) 22 includes:
The coil conductor 24 having a rectangular cross section shown in FIG. 1 is formed on each of the front surface and the back surface of the substrate 21 in a zigzag shape as shown in FIG. 2.
Two zigzag folded portions 22a, 22a are juxtaposed and connected, and these folded portions 22a, 22a are connected by a connecting portion 22b. The coil conductor 24 extends over the folded portions 22a, 22a and the connecting portion 22b. A terminal pad 24a is formed at an end of the coil conductor 24 on the outer peripheral side of the coil main body 22, and a terminal pad 24b is formed at an end of the coil conductor 24 on the inner peripheral side of the coil main body 22, respectively. Have been. It should be noted that, in this embodiment, the folded portion 22 is folded.
It is needless to say that a shape formed by connecting three or more required a's is included in the concept of the skewing type, and the number of turns of the coil conductor 24 is not limited to eight but is required for the thin magnetic element 20. Any number is acceptable.

The substrate (substrate) 21 is made of an insulating non-magnetic material made of resin such as polyimide or ceramic. Next, the magnetic thin film 23 is formed of a special soft magnetic material having a high specific resistance described below. The special soft magnetic material constituting the magnetic thin film 23 is a lanthanoid rare earth metal element (La, Ce, Pr, Nd) in which one or more selected from Fe, Co, and Ni are used as the element A. , Pm,
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, L
u, one or more of them) and Ti, Zr, H
M is one or more elements selected from the group consisting of f, V, Nb, Ta, and W, and Al, Si, Cr, Pt, R
one or two selected from the group consisting of u, Rh, Pd, and Ir
M ′ represents one or more kinds of elements, and one or two of O and N
When at least one kind of element is represented by L, it is represented by the following composition formula. _{A a M b M 'c L} d a that indicates the composition ratio in the above composition formula, b, c, d are in atomic%, 20 ≦ a ≦ 85,5 ≦ b ≦ 30,0 ≦ c ≦ 10,1
It is preferable to satisfy the relationship of 5 ≦ d ≦ 55. Further, the magnetic thin film has the composition described above, and Fe, Co, N
i, a microcrystalline phase having an average crystal grain size of 30 nm or less as a main component and an amorphous compound mainly containing a compound of elements M and O or a compound of elements M and N; It may be composed of phases.

More specifically, when the composition of the constituent material of the magnetic thin film is a composition system of Fe _e M _f O _g , the composition ratio e, f, g
Is in atomic% 50 ≦ e ≦ 70, 5 ≦ f ≦ 30, 10 ≦ g ≦
More preferably, the relationship of 40 is satisfied.
Further, the composition of the constituent material of the magnetic thin film when a Fe _h M _'i O _j becomes composition system, a composition ratio h, i, j is, 45 ≦ h ≦ with atomic%
More preferably, the relationship of 70, 5 ≦ i ≦ 30, and 10 ≦ j ≦ 40 is satisfied. Next, in the case of a composition system of Fe _k M _l N _m , the composition ratio k, l, m is atomic%.
It is more preferable that the following relationship is satisfied: 60 ≦ k ≦ 80, 10 ≦ l ≦ 15, 5 ≦ m ≦ 30.

[0015] In the constituent material of the magnetic thin film, Fe is a main component and is an element responsible for magnetism. In order to obtain a high saturation magnetic flux density, it is preferable to increase the amount of Fe.
In the e-M-N system, when the content exceeds 80 atomic%, the specific resistance tends to decrease. On the other hand, when Fe is less than the range of the present invention, the specific resistance can be increased, but the saturation magnetic flux density decreases. Rare earth elements, or Ti, Zr,
Element M selected from the group of Hf, V, Nb, Ta, W
Is necessary to obtain soft magnetic characteristics. These easily bond with oxygen or nitrogen, and form an oxide or a nitride by bonding. In addition, Al, Si, and B can be mentioned as an element easily connected to oxygen and nitrogen. The specific resistance can be increased by adjusting the content of the oxide or nitride.
The element M ′ is an element added for improving corrosion resistance and adjusting magnetostriction. For these purposes, it is preferable to include the element M ′ in the above range. On the other hand, if the above composition range, the magnetic thin film, 400 ~
A high specific resistance in the range of 2.0 × 10 ⁵ μΩ · cm can be obtained, eddy current loss can be reduced by increasing the specific resistance, and a decrease in high-frequency magnetic permeability is suppressed, and high-frequency characteristics are improved. Is done. In particular, it is considered that Hf has an effect of suppressing magnetostriction.

In order to manufacture the thin magnetic element 20 having the above-described structure, a serpentine coil main body 22 is formed on the front and back surfaces of the substrate 21 by a conventional method such as a film forming method, a plating method, and a screen printing method. Then, the substrate 21 and the coil body 22
A magnetic thin film 23 made of a high-resistance (high-ρ) AMM′-L-based soft magnetic alloy thin film is formed on the front surface or the rear surface thereof so as to cover them. Regarding the means for forming the magnetic thin film 23, the present inventors first described in Japanese Patent Application No. Hei.
3833 (JP-A-6-316748), Japanese Patent Application No. 6-316
No. 57890 (JP-A-7-268610) and the like, but basically, a thin film forming method such as sputtering or vapor deposition is used.

Here, for example, RF is used as a sputtering apparatus.
Bipolar sputtering, DC sputtering, magnetron sputtering,
Existing sources such as tripolar sputtering, ion beam sputtering, and facing target type sputtering can be used. Next, as a method of adding O or N to the magnetic thin film,
Reactive sputtering in which sputtering is performed in an Ar + O ₂ or Ar + N ₂ mixed atmosphere gas in which an oxygen gas or a nitrogen gas is mixed in an inert gas such as Ar is effective. Also, F
It can also be manufactured in an inert gas such as Ar using a composite target in which Fe, element M, or an oxide or nitride thereof is arranged on e, FeM, or an FeM-based alloy target. Further, a rare earth element or T
It can also be manufactured in an inert gas such as Ar using a composite target or the like on which pellets made of i, Zr, Hf, V, Nb, Ta, W, etc. are arranged. The magnetic thin film of the above-mentioned composition system obtained by these film forming methods basically has an amorphous phase as it is, or has a structure in which a crystalline phase and an amorphous phase are mixed.

After forming a magnetic thin film having a desired composition,
A microcrystalline phase can be precipitated in the magnetic thin film by performing an annealing treatment of heating to 300 to 600 ° C. and gradually cooling.
The soft magnetic thin film may be annealed to partially precipitate a crystalline phase, but the proportion of this crystalline phase is preferably less than 50%. If the proportion of the crystal phase exceeds 50%, the magnetic permeability in a high frequency range decreases. Here, the crystal grains precipitated in the structure are fine grains having a grain size of about several nm to 30 nm, and the average grain size is preferably 10 nm or less. By precipitating such fine crystal grains, the saturation magnetic flux density can be increased. The amorphous phase is thought to contribute to an increase in the specific resistance, and the presence of the amorphous phase increases the specific resistance, thereby preventing a decrease in magnetic permeability in a high frequency range.

The thin magnetic element 20 having the structure shown in FIGS. 1 and 2
In this case, the number of components is smaller than that of the coil K having the conventional structure shown in FIGS. 13 and 14, so that it is not necessary to use a different type of film forming apparatus, and the film forming process can be simplified and the manufacturing process can be simplified. Since the laminating operation is unnecessary, the effect of improving the yield can be obtained. In the thin magnetic element 20, when the coil conductor 24 on one surface of the substrate 21 is a primary coil and the coil conductor 24 on the other surface of the substrate 21 is a secondary coil, the thin magnetic element 20 can be used as a transformer.

Further, when a current flows through the coil conductor 24, a magnetic flux is generated around the periphery of the cross section of the coil conductor 24. Here, since the magnetic thin film 23 is in close contact with the coil conductor 24, FIG. Unlike the conventional coil K shown in FIG. 1, the magnetic flux sufficiently enters the inside of the magnetic thin film 23, and the efficiency is improved. Further, in the conventional structure, a large eddy current is generated around the coil to cause a loss. However, if the structure using the magnetic thin film 23 having a high specific resistance is used, the eddy current is less generated in a high frequency region and the loss is reduced. A small thin magnetic element 20 can be provided. In addition, since the thin magnetic element 20 can be reduced in loss, the thin magnetic element 20 and a transformer including the same can have a structure that can withstand high power, and a reduction in size and weight can be realized.

Next, in the case of the serpentine coil main body 22 shown in FIG. 2, the magnetic flux in the direction shown by the arrow a and the magnetic flux in the direction shown by the arrow b are sequentially formed in the folded portion 22a from the top in FIG. Occurs twice. That is, as shown in FIG. 2, the arrow a in the same direction extends over the eight coil conductors 24 from the top.
A magnetic flux in the direction indicated by arrow b in the next eight coil conductors 24, and a magnetic flux in the direction indicated by arrow a in the same direction over the next eight coil conductors 24. Further, the next eight coil conductors 24 have opposite arrows b.
Generates magnetic flux in the direction. Since the magnetic flux is generated as described above, in the boundary portion where the direction of the magnetic flux is different, the magnetic flux becomes opposite in the adjacent coil conductors 24, 24, so that the magnetic flux does not easily fly to the adjacent coil conductor 24, and Loss between the conductors 24 is less likely to occur.

The reason why the magnetic thin film 23 can be brought into close contact with the coil conductor 24 is that the soft magnetic material of the above-mentioned system constituting the magnetic thin film 23 has a sufficiently high specific resistance. In the constituent materials of the magnetic thin film 23 of the above system, for example,
No. 748, Fe _46.2 Hf
_With a magnetic thin film having a composition of _18.2 O _35.6 , a specific resistance of 133709 μΩ · cm can be obtained as a specific resistance ρ. Moreover, the specific resistance value of the magnetic thin film having this composition is after the heat treatment, and is 194,000 μΩ before the heat treatment.
-Specific resistance of cm can be obtained. In addition, FeHfO-based, FeZrO-based, FeNbO-based, FeTa
O-based, FeTiO-based, FeVO-based, FeWO-based, FeY
O system, FeCeO system, FeSmO system, FeHoO system, F
eGdO system, FeTbO system, FeDyO system, FeErO
In the system, 215 to 1767 μΩ ·
A specific resistance of about cm can be easily obtained. Further, as shown in Tables 1 and 2 attached to JP-A-7-268610, a specific resistance of about 200 to 400 can be easily obtained even in the case of FeHfN. Therefore, even if the magnetic thin film 23 is formed in close contact with the coil conductor 24 by selecting a composition having a high specific resistance, it is possible to provide the coil body 22 which does not cause a current leak. Further, among the magnetic thin films of these systems, in the case of the FeMO system,
As disclosed in Table 1 attached to 316748, 1-1.
A saturation magnetic flux density of 5 T (10 to 15 kG) can be obtained. In the case of the FeMN system, a saturation magnetic flux density exceeding 1 T (10 kG) can be easily obtained as disclosed in Table 1 of JP-A-7-26810. In any system, a magnetic flux density of 10 kG or more, which is much higher than the saturation magnetic flux density of 5 kG of ferrite or the like, can be easily obtained.

FIG. 3 shows a second embodiment according to the present invention. The thin magnetic element 30 of this embodiment differs from the previous embodiment in that an insulating material is provided between the coil conductor 24 and the magnetic thin film 23. This is the point where the film 31 is interposed. This insulating film 31
Is made of an insulating material such as SiO ₂ , Al ₂ O ₃ , Si ₃ N ₄ , Ta ₂ O ₅ , or a polymer film such as polyimide. Other structures are the same as those of the previous example, and the same portions are denoted by the same reference numerals and description thereof will be omitted.

The basic operation and effect of the structure of the thin magnetic element 30 of this embodiment are the same as those of the thin magnetic element 20 of the previous embodiment.
Is equivalent to The reason why the insulating film 31 is provided in this embodiment is to completely prevent the current flowing through the coil conductor 24 from leaking to the magnetic thin film 23 side. As described above, if the magnetic thin film 23 has the above-described composition, the specific resistance is high, but the specific resistance varies depending on the composition.
Is preferably provided.

FIG. 4A shows a third embodiment according to the present invention. In the thin magnetic element 35 of this embodiment, a magnetic thin film 36 is formed on one surface of a substrate 21 so as to cover the entire surface. An insulating film 37 covering the entire surface of the magnetic thin film 36
Is formed, the coil conductor 24 is formed on the insulating film 37, the coil conductor 24 is further covered with the insulating film 38 continuous with the insulating film 37, and the insulating films 37 and 38 are further covered with the magnetic thin film 39. Have been. In this embodiment, the magnetic thin films 36 and 38 are formed of the same soft magnetic material as the magnetic thin film 23 of the above-described embodiment, and the insulating films 37 and 38 are formed of the same material as the insulating film 31 described above.

In the structure of this embodiment, the magnetic thin films 36 and 39 surround the coil conductor 24.
As shown by arrows e and f in (B), an annular magnetic flux is generated around the magnetic thin films 36 and 39 around the coil conductor 24. Further, the annular magnetic flux generated around the coil conductor 24 is divided by the insulating film 37, but the divided portion is an extremely narrow region, and the insulating film 37 acts as a gap. It is formed annularly over the thin films 36 and 39.

FIG. 5A shows a fourth embodiment according to the present invention. In this embodiment, a thin magnetic element 40 has the same structure as that of the first embodiment on both surfaces of a substrate 41. A coil conductor 42 is provided, and an insulating film 43 covering each side surface and each top surface of each coil conductor 42 is formed.
A through-hole 44 is formed in the substrate 41 around the
The magnetic thin film 45 is formed so as to cover the front and back surfaces and the insulating film 43 and fill the through hole 44.
Even with the thin magnetic element 40 of this embodiment, the same effect as the structure of the first embodiment can be obtained. When the transformer is configured by regarding the coil conductor 42 on the upper side of the substrate 41 as the primary side and the coil conductor 42 on the lower side of the substrate 41 as the secondary side, the periphery of the coil conductor 42 is shown in FIG. As described above, the magnetic flux is generated so as to orbit the coil conductors 42 with respect to the cross section of the coil conductors 42 on both sides of the substrate 41. The magnetic flux generated here is generated in the magnetic thin film 45, and there is nothing obstructing the magnetic flux in the middle of the path where the magnetic flux is generated. As a result, the flux linkage increases, so that a transformer with good efficiency and high coupling coefficient can be obtained. Further, in FIG. 5B, if the directions of the magnetic fluxes of the coil conductors 42, 42 adjacent to each other in the left-right direction are opposite to each other, no leakage or jumping of the magnetic flux from around the right and left adjacent conductors occurs, so that a loss occurs. hard. Therefore, with the transformer having this structure, the energy input to the primary side can be extracted without loss at the secondary side, and the generated noise can be reduced.

FIG. 6 shows another example of the coil conductor used in each of the above-described embodiments. The coil conductor 46 of this example is generally called a meander type, and is linearly adjacent to each other in parallel. A plurality of conductor pieces 47 are connected in a connecting portion 48 to form a zigzag shape. This coil conductor 46
Is generated such that the directions of the magnetic flux in the plurality of adjacent conductor pieces 47 are alternately opposite as shown by arrows i or j. Therefore, unlike the case where the windings of the skew-shaped coil conductors shown above are grouped by several and the direction of the magnetic flux is reversed, the direction of the magnetic flux is reversed with each of the conductor pieces 47. Leakage and penetration of magnetic flux from the periphery of the adjacent conductor pieces 47, 47 are further reduced, and the structure is more suitable for high frequency.
It can be used as a coil conductor with little loss in the z-band high frequency band.

FIG. 7 shows a fifth embodiment according to the present invention.
On one surface, a magnetic thin film 52 and an insulating film 53 are laminated, and on the insulating film 53, a coil conductor 54 is formed in a spiral shape as shown in FIG. And a magnetic thin film 56 is formed to cover the insulating films 53 and 55 and the concave portion formed by them. In this embodiment, if the coil conductor 54 is of the spiral type shown in FIG. 9, the magnetic flux circling around each coil conductor 54 as shown by the arrow in FIG. , Magnetic thin film 52, 5
The directions of the magnetic flux converging on the portion 6 are the directions of P and Q, respectively. When the spiral coil conductor 54 is used as described above, the direction of the magnetic flux directed to the film surface direction of the magnetic thin films 52 and 56 adjacent thereto is important, and the magnetic flux in the film surface direction is generated smoothly. This has the effect of improving efficiency.

At this point, the structure shown in FIG.
Unlike the structure shown in FIGS. 1 and 3 to 5, flattened magnetic thin films 52 and 56 are provided around the coil conductor 54, and the coil conductor 54 is provided around the coil conductor 54 as shown in FIGS. 1 and 3 to 5. Since the magnetic thin film is different from the magnetic thin film having an uneven shape, a magnetic flux component is generated in the P direction or the Q direction in parallel with the film surface, so that the efficiency is improved. In the case of the magnetic flux generated in this structure, the insulating film 53 acts as a gap and prevents the magnetic flux from being concentrated only near the coil conductor, so that the magnetic flux is dispersed and the uniformity of the magnetic flux in the film surface direction is improved. It has the effect of further increasing. Other effects are the same as those of the third embodiment. This also gives
The nonlinear magnetic characteristics are improved, the magnetic saturation when a large current flows is reduced, and the present invention can be applied to a large-current microreactor or microtransformer.

FIG. 8 shows a sixth embodiment according to the present invention.
A magnetic thin film 62 and an insulating film 63 are laminated on one surface, and a coil conductor 64 is formed on the insulating film 63 in a spiral shape as shown in FIG. Is coated, and the upper surface of the insulating film 63 and the insulating film 6
A magnetic layer 66 is formed so as to cover the side surfaces of the magnetic layer 5 and the recesses formed by them, and a planar magnetic thin film 67 is formed so as to cover the top surfaces of the magnetic layer 65 and the insulating film 65.

In this embodiment, the material forming the magnetic thin film 67 is a soft magnetic material having a high specific resistance of the system described above, but the magnetic material forming the preliminary magnetic layer 66 is formed by plating or the like. Ni-Fe, Co-Fe, Ni-
It is made of Fe-Co or the like. In the magnetic layer 66, the thickness of the coil conductor 64 is increased, and a soft magnetic material having a high specific resistance formed by a film forming method such as sputtering is formed around the coil conductor 64 in accordance with the thickness of the coil conductor 64. This is effective when sufficient filling is not possible. With this structure, the same effect as that of the fifth embodiment described above can be obtained. In addition, in this embodiment, the thickness of the coil conductor 64 is such that it cannot be formed by a film forming method such as sputtering, and the magnetic layer is thick enough to cover the coil conductor 64. Such a structure is effective in forming the 66, whereby the present invention can be applied to a thin magnetic element in which the cross-sectional area of the coil conductor 64 is large and a large amount of current can flow. Other effects are the same as those of the fifth embodiment.

Next, an example of a method of manufacturing the thin magnetic element 40 according to the fourth embodiment described above with reference to FIG. 5 will be described below with reference to FIGS. In order to manufacture the thin magnetic element 40, the coil conductors 42 are formed on the front side and the back side of the substrate 71 shown in FIG. 10 by a conventional method such as a film forming method, a plating method, or a screen printing method. Next, an insulating film is formed so as to cover the coil conductor 42 and the substrate 71, a part of the insulating film is removed by etching in a photolithography process, and as shown in FIG. A covering insulating film 43 is formed.

Next, a resist 7 is applied so as to cover the insulating film 43.
3 and etching is performed based on the resist 73 to form a through hole 44 in the portion of the substrate 71 not covered by the resist 73, and the resist 73 is removed to remove the substrate 41 having the through hole 44 shown in FIG. Get. When a polyimide substrate is used as the substrate 71, an etchant such as hydrazine that dissolves the polyimide can be used. FIG.
When the substrate 42 shown in FIG. 5 is obtained, a magnetic thin film of a soft magnetic alloy having a high specific resistance of the above-described composition system is formed on both sides of the substrate 42 by a film forming method. The magnetic element 40 can be obtained.

[0035]

EXAMPLES on the upper and lower surfaces of the rolled copper foil made of the planar coil shape shown in FIG. 2, the thickness of 1μm made of SiO ₂ sputter membrane
A thin magnetic element having a configuration in which the following insulating film and a magnetic thin film having a composition of Fe ₅₅ Hf ₁₁ O ₃₄ having a thickness of 1 to 3 μm were laminated as shown in FIG. 3 was produced. The dimensions of the planar coil are, in the planar shape shown in FIG.
2.0 mm, horizontal width of folded portion 22a 16.0 mm, line width of coil conductor 0.4 mm, line interval 0.1 mm, thickness 105
The number of turns was 2 (the number of folded portions was 2), and the number of turns was 8.

FIG. 15 shows the results of measuring the frequency characteristics using an impedance analyzer (4191A, 4192A, manufactured by Hewlett-Packard Company) using the thin magnetic element having the above shape as a reactor. As a comparative example, the measurement results obtained when a Co-based amorphous magnetic ribbon having a thickness of 20 μm (sample symbol A) was used are also shown.

In the comparative sample using a Co-based amorphous magnetic ribbon, the equivalent inductance L was reduced and the equivalent resistance R was increased due to the influence of eddy current, while FeHf
The sample of the present invention using a magnetic thin film of O has almost no influence of eddy current, and has a FeHfO
It is clear that the sample of the present invention using the magnetic thin film has better characteristics. In addition, the performance coefficient Q (= WL
/ R) show characteristics having a maximum value with respect to f, and C
The comparative sample using the o-based amorphous magnetic ribbon is f = 1
The sample of the present invention using a magnetic thin film of FeHfO at a maximum value of 5 at 00 kHz has a maximum value of 11 at f = 2 MHz. The difference in L at f = 10 kHz is considered to be due to the difference in the thickness of the magnetic layer.

Next, FIG. 16 shows the result of measurement of the load characteristics when the reactor having the above structure is used for a step-down converter.
Shown in The experiment was performed with a switching cycle of f = 1 MHz, an on-time ratio of D = 0.5, and an input voltage of Vi = 8V. The magnetic film used was formed in a rotating magnetic field and had the composition Fe Hf
O 2, having a thickness of 3 μm and having a saturation magnetization Is = 1.3
T, μ ′ = 1400 at 1 MHz, μ ′ / μ ″ = 14
0, and the specific resistance ρ was 5 μΩm. From the results shown in FIG. 16, it can be seen that the sample of the present invention using the magnetic thin film of FeHfO has output voltage V ₀ , output power P _0, and efficiency η as compared with the comparative sample using the Co-based amorphous magnetic ribbon. Both are high. This is considered to be because the loss equivalent resistance of the FeHfO magnetic thin film is lower than the loss equivalent resistance of the Co-based amorphous magnetic ribbon.
Further, a stable result was obtained at around η = 80% near I ₀ = 300 mA. This is presumably because the increase in η due to the inductance component and the decrease in η due to the loss resistance are almost the same, and the increase in η and the decrease in η due to the loss resistance are almost the same.

In FIG. 15, the equivalent resistance R is a resistance component of the impedance, and the impedance Z
Is expressed as Z = {R ² + (ωL−1 / ωC) ² } ^0.5 , and theoretically the equivalent resistance does not depend on the frequency, but in an actual reactor, it becomes frequency dependent. In this example, 1
The value of / ωC is 0. The performance coefficient Q in FIG.
Since Q = ωL / R, the smaller the equivalent resistance R, the larger the performance coefficient Q and the higher the efficiency η. Therefore, in order to obtain an efficient reactor, it is preferable that the equivalent resistance R is small. The equivalent inductance L is an inductance component of the impedance. Also, the magnetic element according to the present invention can be used for any DC-DC converter such as a step-up type, a step-up / step-down type, etc. in addition to the step-down type.

[0040]

As described above, since the thin magnetic element of the present invention has a magnetic thin film covering a coil pattern,
A thin magnetic element can be configured with a minimum number of parts by the coil pattern and the magnetic thin film, and furthermore, the magnetic flux generated by the coil pattern can be efficiently introduced into the magnetic thin film, thereby reducing the loss and reducing the thickness. A magnetic element can be provided. By providing the magnetic thin film in contact with the coil pattern, the magnetic flux generated by the coil pattern can be directly and efficiently introduced into the magnetic thin film, and a thin magnetic element with less loss can be provided. By using a configuration in which the coil pattern is wrapped around with a magnetic thin film, a closed magnetic path is formed by the magnetic thin film around the coil pattern, and the magnetic flux generated in a ring around the cross section of the coil pattern is efficiently converted to the magnetic thin film. Since it is introduced, a thin magnetic element having less leakage magnetic flux and more interlinkage magnetic flux and further lowering loss can be provided. In the case of the magnetic element having the above-described configuration, if the coil pattern has a meandering or serpentine planar shape, a thin magnetic element having low eddy current loss and excellent high-frequency characteristics can be provided.

If the surface of the magnetic thin film surrounding the coil pattern is a flat type which is not influenced by the unevenness of the coil pattern, the magnetic thin film does not have the unevenness corresponding to the unevenness of the coil pattern. It is possible to provide a thin magnetic element excellent in high-frequency characteristics with a large amount of interlinkage magnetic flux, a small eddy current loss and no magnetic flux disturbance due to the presence. Furthermore, by covering the uneven portion of the coil pattern with another magnetic layer different from the magnetic thin film and providing a flat type magnetic thin film so as to sandwich the coil pattern, disturbance of magnetic flux due to the presence of the uneven portion of the magnetic thin film is provided. And a thin magnetic element having high interlinkage magnetic flux and excellent high-frequency characteristics with little eddy current loss can be provided.

Next, a fine crystal phase containing any of Fe, Co, and Ni, a rare earth element, Ti, Zr, Hf, Ta,
By forming a magnetic thin film from an amorphous phase mainly containing an element M of any of Nb, Mo, and W and a compound of O or N, a magnetic layer having a high specific resistance and a saturation magnetic flux density exceeding 10 kG can be obtained. Can be formed, whereby a highly efficient thin device can be obtained. In addition, since the magnetic thin film made of this type of soft magnetic material has a high resistance, eddy current loss can be suppressed low, and a thin magnetic element having good high-frequency characteristics and capable of being reduced in size and weight can be provided. In addition, if a magnetic thin film having a high specific resistance is used, a structure in which the magnetic thin film is directly contacted with the coil pattern directly without using an insulating film can be adopted without a risk of current leakage. By efficiently guiding the magnetic flux generated by the pattern into the magnetic thin film, a highly efficient thin magnetic element can be provided.

[0043] The magnetic thin _{film, A a M b M 'c} L d becomes represented by compositional formula, the composition ratio a, b, c, d in atomic%, 20 ≦ a
≦ 85, 5 ≦ b ≦ 30, 0 ≦ c ≦ 10, and 15 ≦ d ≦ 55, so as to have a high saturation magnetic flux density of 10 kG exceeding the ferrite having a saturation magnetic flux density of 5 kG, A thin magnetic element with a small eddy current loss and a magnetic thin film having a high specific resistance in the range of several hundreds to 2 × 10 ⁵ μΩ · cm can be provided.

Next, in the manufacturing method of the present invention, after forming a coil conductor on the base and covering it with an insulating film, a through-hole is formed in the base around the coil conductor in a photolithography step, and a magnetic thin film is formed so as to cover these. Is formed, a thin magnetic element having a configuration in which the periphery of the coil conductor is reliably covered with the magnetic thin film can be easily manufactured. Also, as the magnetic thin film used,
By using the composition described above, it is possible to reliably form a magnetic thin film having a high saturation magnetic flux density with a high specific resistance.
An efficient thin magnetic element having excellent high frequency characteristics can be manufactured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a thin magnetic element according to the present invention.

FIG. 2 is a plan view showing the first embodiment of the thin magnetic element according to the present invention.

FIG. 3 is a sectional view showing a second embodiment of the thin magnetic element according to the present invention.

FIG. 4A is a sectional view showing a third embodiment of a thin magnetic element according to the present invention, and FIG. 4B is a sectional view showing FIG.
FIG. 4 is a diagram showing the direction of magnetic flux around the coil conductor shown in FIG.

5A is a sectional view showing a fourth embodiment of a thin magnetic element according to the present invention, and FIG. 5B is a sectional view showing FIG.
FIG. 4 is a diagram showing the direction of magnetic flux around the coil conductor shown in FIG.

FIG. 6 is a diagram showing a planar shape of a specially shaped coil conductor used in the thin magnetic element according to the present invention.

FIG. 7 is a sectional view showing a fourth embodiment of the thin magnetic element according to the present invention.

FIG. 8 is a sectional view showing a fifth embodiment of the thin magnetic element according to the present invention.

FIG. 9 is a cross-sectional view showing another example of the coil main body used in the thin magnetic element according to the present invention.

FIG. 10 is a cross-sectional view for explaining the method of manufacturing the thin magnetic element shown in FIG. 5A and showing a state where a coil conductor and an insulating film are formed on a substrate.

FIG. 11 is a cross-sectional view for explaining the method of manufacturing the thin magnetic element shown in FIG. 5A, showing a state in which the coil conductor and the insulating film on the substrate are covered with resist.

FIG. 12 is a cross-sectional view for explaining the method of manufacturing the thin magnetic element shown in FIG. 5A and showing a state in which a through hole is formed on the substrate.

FIG. 13 is a sectional view showing an example of a conventional coil.

FIG. 14 is a plan view showing an example of a coiled coil body.

FIG. 15 is a view showing a result of measuring frequency characteristics using the thin magnetic element according to the present invention as a reactor.

FIG. 16 is a view showing a result of measuring load characteristics when the thin magnetic element according to the present invention is applied to a step-down converter.

[Explanation of symbols]

Substrates 21, 41, 51, 61, coil body 22 (coil pattern), magnetic thin films 23, 39, 45, 56, 62, 67, coil conductors 24, 42, 54, 64, insulating films 31, 37, 38, 43 , 53, 55,
63, 65, magnetic layer 66,

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Hatanai 1-7 Yukiya Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Akihiro Makino 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Inside Alps Electric Co., Ltd. (72) Inventor Yutaka Naito 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Naoya Hasegawa 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Inside Electric Co., Ltd.

Claims (17)

[Claims] 1. A thin magnetic element comprising: a coil pattern formed on at least one surface of a base; and a magnetic thin film formed on the coil pattern so as to cover the coil pattern. 2. The thin magnetic element according to claim 1, wherein said magnetic thin film is provided in contact with said coil pattern. 3. The thin magnetic element according to claim 1, wherein said magnetic thin film is formed on a coil pattern via an insulating film. 4. The method according to claim 2, wherein the coil pattern is formed on a magnetic thin film formed on a substrate, and a coil conductor constituting the coil pattern is surrounded by the magnetic thin film. The thin magnetic element according to the above. 5. A coil pattern is formed on both opposing surfaces of a substrate, a through hole is formed in the substrate between the coil patterns, and magnetic thin films on both sides of the substrate are connected via the through hole. The thin magnetic element according to claim 2. 6. The thin magnetic element according to claim 1, wherein a planar shape of the coil pattern is a meander shape. 7. The thin magnetic element according to claim 1, wherein a planar shape of the coil pattern is formed in a zigzag shape. 8. The thin magnetic element according to claim 1, wherein the magnetic thin film formed on the coil pattern on the base is made flat. 9. A magnetic layer for embedding a coil pattern around a coil pattern on a substrate, wherein a magnetic material of the magnetic layer is different from a magnetic material of a magnetic thin film formed thereon. The thin magnetic element according to claim 8, wherein: 10. A magnetic layer formed around a coil pattern on a substrate, wherein the magnetic layer is mainly composed of one of a Ni—Fe alloy, a Co—Fe alloy, and a Ni—Fe—Co alloy. A thin magnetic element according to claim 9. 11. The thin magnetic element according to claim 9, wherein the magnetic layer formed around the coil pattern on the base is formed by plating. 12. The coil pattern according to claim 1, wherein the planar shape of the coil pattern is a spiral type.
12. The thin magnetic element according to any one of 4, 5, 8, 9, 10 and 11. 13. One or two of Fe, Co, and Ni.
A fine crystal phase having an average crystal grain diameter of 30 nm or less containing at least a seed as a main component, and a lanthanoid-based rare earth element (La, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
one or more of o, Er, Tm, and Lu)
And a magnetic thin film composed of an amorphous phase mainly containing one or more elements M selected from Ti, Zr, Hf, Ta, Nb, Mo and W and a compound of O or N. The thin magnetic element according to claim 1, wherein the thin magnetic element is used for a part or all of the thin magnetic element. 14. The method of claim 13, wherein the magnetic thin film is, _{A a} M _b M 'thin magnetic element according to any one of claims 1 to 14, characterized in that it is represented by _c L _d a composition formula. Where A is Fe,
Represents one or more selected from Co and Ni, and M represents a lanthanoid-based rare earth metal element (La,
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D
one or more of y, Ho, Er, Tm, and Lu) and one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, and W; M '
Are Al, Si, Cr, Pt, Ru, Rh, Pd, Ir
Represents one or more elements selected from the group of
L represents one or two of O and N, and the composition ratio
a, b, c, d are atomic%, 20 ≦ a ≦ 85, 5 ≦ b ≦ 30,
It is assumed that the relationship of 0 ≦ c ≦ 10 and 15 ≦ d ≦ 55 is satisfied. 15. A transformer comprising the thin magnetic element according to claim 1. Description: 16. A coil conductor is formed on a substrate, the top surface and the peripheral surface of the coil conductor are covered with an insulating film, and the outer surface of the insulating film is covered with a resist, and then the substrate is etched to be covered with the resist. A through-hole is formed in the part of the substrate which is not covered, and then the resist is removed to obtain a coil conductor covered with an insulating film and a substrate with a through-hole. Forming a magnetic thin film so as to cover the insulating film and the through hole. 17. The magnetic thin film according to claim 13 or 1,
5. A magnetic thin film according to claim 4, wherein the magnetic thin film is used.
7. The method for manufacturing a thin magnetic element according to item 6.