JP2003282328A - Thin magnetic element, its manufacturing method, and power source module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin magnetic element that is low in DC superposition characteristics and is reduced in magnetic loss in a high-frequency region. <P>SOLUTION: In this thin magnetic element, a sheet-like coil 2, containing a conductor coil 3 and a resin insulating section 4 and a metallic thin film magnetic member 1 having higher permeability than the insulating section 4 are arranged so that the member 1 so as to pinch the coil 2. <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 microminiature thin magnetic element used for an inductance element, a choke coil, a transformer and the like of electronic equipment, a method for manufacturing the same, and a power supply module using the same.

[0002]

2. Description of the Related Art In recent years, as electronic devices have been generally made smaller and thinner, it has been strongly demanded that electronic components and power supply devices used therein be made smaller and thinner. In particular, in portable devices and the like, there is an increasing demand for thinner devices than for miniaturization.

On the other hand, LSIs such as CPUs are becoming high-speed and highly integrated, and a large current may be supplied to a power supply circuit supplied to such an LSI. Therefore, high speed
Inductance elements such as choke coils used in power supply circuits that are supplied to highly integrated LSIs should have a coil conductor with low resistance to realize low heat generation, and the inductance value should not be reduced by DC superimposition (DC Good superposition characteristics) are required. Further, since the used frequency is high, it is required that the loss in the high frequency range is low.

Further, since there is a strong demand to reduce the cost of parts, it is necessary to assemble a component component having a simple shape in a simple process. That is, it is required to inexpensively supply an inductance element and a power source which can be used with a large current and a high frequency and which are small and thin. Among the components used in the power supply circuit, the thickest one is the inductance element. Therefore, thinning of the magnetic element such as the inductance element is strongly desired also for thinning of the power source itself.

Generally, when the magnetic element is downsized, the magnetic path cross-sectional area is reduced and the inductance value is reduced. As a means for improving the characteristics of such a small magnetic element (increasing the inductance value), for example, the actual exploitation 53-
In Japanese Patent No. 136538 and Japanese Patent Laid-Open No. 61-136213, after winding a drum-shaped core material made of ferrite or the like with a collar, winding is performed, the inside of the collar is filled with a mixture of magnetic powder and resin to close the magnetic field. Road structures have been proposed.

In this structure, the bobbin normally used for the winding is not required, the magnetic path cross-sectional area can be increased correspondingly, and the closed magnetic circuit structure is formed, so that the inductance value becomes large,
The characteristics of the magnetic element are improved. However, this structure is intended to reduce the size of the magnetic element and is not intended to be thin, and since the magnetic path length in the mixture of magnetic powder and resin is long, sufficient characteristics are not obtained. There was a problem that could not be said to have been obtained. In addition, an inductance element having a size of, for example, about 2 × 1 × 1 mm is actually commercially available by using such a conventional technique, but this inductance element has a large DC resistance of the coil.

Therefore, in order to realize a magnetic element having a low DC resistance and a large inductance value, it is necessary to manufacture a coil using a thick conductor wire and increase the number of turns. However, in order to reduce the thickness, at the same time, make the thickness 1 m.
Since it is necessary to make it as small as about m or less, it is desirable to wind the coil in a plane shape. In order to secure a space for accommodating this planar coil, the size should be 2 to 10 mm.
It will be a big corner. However, such an area /
In a thin structure with a large thickness ratio, the magnetic flux leakage increases,
It is difficult to obtain a large inductance value.

As a technique aimed at improving the characteristics of such a thin magnetic element (reducing the leakage flux), Japanese Patent Laid-Open No. 6-3
Japanese Patent No. 42725 proposes a structure in which a conductor (planar coil) is embedded in a paste of ferrite and resin, and ferrite plates are attached to the upper and lower sides of the paste. Further, Japanese Patent Application Laid-Open No. 9-270334 proposes a structure in which a planar coil is embedded in a resin containing magnetic powder and metal magnetic plates are attached to the upper and lower sides thereof. These structures are designed so that the magnetic flux having a high magnetic permeability is arranged on the outer surface so that the leakage magnetic flux is relatively small even if the magnetic body is made thin and the characteristics are sufficiently exhibited.

[0009]

However, in the magnetic element disclosed in JP-A-6-342725 and JP-A-9-270334, the planar coil itself is completely embedded in the resin containing the magnetic powder. Due to this structure, the resin containing magnetic powder is present between and around the conductors of the planar coil. Therefore, crossing the magnetic path that is a shorter path than the original magnetic path that passes through the outer peripheral portion of the planar coil, that is, the conductor of the planar coil,
A magnetic path that crosses between adjacent conductors is likely to occur. When the conductors of the planar coil and the magnetic flux passing between the conductors thus increase, there arises a problem that the magnetic loss increases and the inductance value also decreases in the high frequency range.

In order to further reduce the thickness of the magnetic element (for example, the area / thickness ratio> 0.4 or more), the upper and lower magnetic members of the coil have extremely thin cross-sectional areas. There is a problem that the inductance value, especially the DC superposition characteristic, deteriorates more than ever before. For that purpose, a magnetic material having a high saturation magnetic flux density and a magnetic permeability of a certain level or more is indispensable even if the magnetic member is thin. In addition, after mounting the magnetic element, the circuit board may be warped, dropped, heat shocked, or the like, causing problems such as disconnection of the conductor coil, short circuit, or missing of the magnetic member.

The present invention is directed to solving these problems.
It is an object of the present invention to provide a thin magnetic element having excellent magnetic characteristics, particularly DC superimposition characteristics, little magnetic loss in a high frequency range, and excellent reliability. Another object of the present invention is to provide a manufacturing method for manufacturing such a magnetic element with high productivity and a power supply module including such a magnetic element.

[0012]

To solve the above problems, the present invention has the following constitution.

The invention according to claim 1 of the present invention is a sheet-shaped coil including a conductor coil and a resin insulating portion, and a metal thin film magnetic member having a magnetic permeability higher than that of the resin insulating portion so as to sandwich the sheet-shaped coil. Since a sheet-shaped coil including a conductor coil and a resin insulating portion having a magnetic permeability smaller than that of the upper and lower metal thin film magnetic members is used as the thin magnetic element, the magnetic flux crossing between the conductor of the conductor coil and the adjacent conductors is reduced. It is possible to realize a thin magnetic element which is suppressed and which is excellent in DC superposition characteristics and has less magnetic loss in a high frequency region by disposing the metal thin film magnetic member.

According to a second aspect of the present invention, a sheet-shaped coil including a conductor coil and a resin insulating portion, and a metal thin film magnetic member having a magnetic permeability higher than that of the resin insulating portion so as to sandwich the sheet-shaped coil. And the metal thin film magnetic member is a thin magnetic element arranged in at least one location selected from the central portion and the peripheral portion of the sheet-shaped coil without the conductor coil between the metal thin film magnetic members. It is possible to provide a thin magnetic element that is excellent in direct current superposition characteristics and has little magnetic loss in a high frequency range.

In the invention according to claim 3 of the present invention, the main composition of the metal thin film magnetic member is composed of Fe, Co and Ni, and the total content of Fe and Co is 50 wt% or more. The thin magnetic element according to any one of the above items, a metal thin film magnetic member having a high saturation magnetic flux density can be obtained, and a thinner magnetic element having excellent DC superposition characteristics can be realized.

The invention according to claim 4 of the present invention is the thin magnetic element according to any one of claims 1 and 2, wherein the metal thin film magnetic member has a laminated structure of different metal magnetic members. It is possible to realize a thin magnetic element having excellent high frequency characteristics.

The invention according to claim 5 of the present invention is the thin magnetic element according to claim 4, wherein the metal thin film magnetic member is composed of a laminated structure of a crystalline metal magnetic thin film and an amorphous metal magnetic thin film. A thin magnetic element having the same effect as that of claim 4 can be realized.

According to a sixth aspect of the present invention, the metal thin film magnetic member has a saturation magnetic flux density of 1.0 T or more and a magnetic permeability of 300.
The thin magnetic element according to any one of claims 1 and 2 as described above, and it is possible to realize a thin magnetic element having excellent DC superposition characteristics.

The invention according to claim 7 of the present invention is the thin magnetic element according to any one of claims 1 and 2, which is a metal thin film magnetic member having a thickness of 10 μm or more and 100 μm or less. It is possible to realize a thin magnetic element having excellent characteristics and having little magnetic loss in a high frequency range.

In the invention according to claim 8 of the present invention, the conductor coil is a two-stage coil which is divided into upper and lower two stages and wound in a planar shape, and the upper and lower two-stage coils are formed in the innermost peripheral portion. The thin magnetic element according to any one of claims 1 and 2, which are connected to each other, wherein the space factor of the conductor coil can be increased and the end of the conductor coil is located on the outermost side of the coil. In addition, the terminal portions can be easily taken out without providing holes in the metal thin film magnetic members arranged above and below.

According to a ninth aspect of the present invention, the resin insulating portion contains at least one kind of epoxy resin, phenol resin, polyimide resin, silicon resin or modified resin thereof. And the thin magnetic element having high productivity can be realized.

According to a tenth aspect of the present invention, the sheet-shaped coil is provided inside or on the surface of the wiring board as a part of the wiring layer of the wiring board. The thin magnetic element described above makes it possible to easily form the thin magnetic element disposed inside or on the surface of the wiring board.

According to an eleventh aspect of the present invention, a step of producing a sheet-shaped coil by incorporating a conductor coil in a resin insulating portion, and a metal thin-film magnetic member having a predetermined shape by plating on and under the sheet-shaped coil are provided. It is a method for manufacturing a thin magnetic element including a step of forming a thin magnetic element, and it is possible to manufacture a thin magnetic element by a simple method, and reliability and productivity can be improved.

According to a twelfth aspect of the present invention, there is provided a step of producing a sheet coil by incorporating a conductor coil in a resin insulating portion, and a metal thin film magnetic member is formed on the sheet coil by sputtering and vapor deposition. A method for manufacturing a thin magnetic element including a step of forming into a predetermined shape. It becomes possible to manufacture a thin magnetic element using a conventional relatively simple thin film method, and a method for manufacturing a small thin magnetic element is provided. can do.

A thirteenth aspect of the present invention is a power supply module in which the thin magnetic element according to any one of the first and second aspects, a semiconductor chip, and a chip component are mounted on a wiring board. It is possible to realize a thin and high-performance power supply module.

As described above, the thin magnetic element of the present invention is a thin magnetic element having a high inductance value, a low coil DC resistance, and a good DC superposition characteristic. Therefore,
A power supply module manufactured by mounting other components such as a wiring board, a semiconductor chip, and a capacitor on this thin magnetic element is also available.
It is excellent in the above characteristics and can be made thin.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a thin magnetic element of the present invention will be described with reference to the drawings.

Hereinafter, an example of a thin magnetic element used for an inductance element or a choke coil will be described, but the present invention is not limited to this, and even if it is used for a transformer or the like which requires a secondary winding. It is effective. FIG. 1 is a sectional view of a thin inductance element that is an example of an embodiment of the present invention. 2 and 3 are sectional views of a thin inductance element showing another embodiment different from that shown in FIG. Each thin inductance element will be described below.

The thin inductance element shown in FIG. 1 comprises a sheet coil 2 composed of a conductor coil 3 and a resin insulating portion 4.
Is sandwiched between the metal thin film magnetic members 1a and 1b.

In the conductor coil 3, the conductor is wound in two steps in a planar shape and covered with the resin insulating portion 4, and the upper and lower conductors are connected at the innermost peripheral portion 3a. The terminal portion 3b of the conductor coil 3 is taken out from the outermost circumference of the coil. In the case of the thin inductance element shown in FIG. 1, the terminal portions 3b of the sheet-shaped coil 2 are taken out in mutually different directions, but they may be taken out in the same direction.

In addition, thin magnetic elements are often mounted on a circuit board or the like for use, and recently, high-density mounting technology has been rapidly developed, and circuit design for arranging wiring under the magnetic element is performed. It is being appreciated. Therefore, if the metal thin film magnetic member 1 is exposed, a short circuit may occur. In some cases, only the terminal portion 3b may be exposed and the outer coating 14 may be used for insulation coating. From the viewpoint of heat resistance and plasticity, the exterior material is preferably an insulating resin containing at least one type of epoxy resin, phenol resin, polyimide resin, silicon resin or modified resin thereof. The effect of the outer package 14 can further improve the insulation and reliability.

In the thin inductance element shown in FIG. 2, the sheet-shaped coil 2 is arranged between the metal thin film magnetic members 1a and 1b, and the metal magnetic member 5 is also arranged at the center of the sheet-shaped coil 2. Is. Further, the metal thin film magnetic members 1a and 1b may be provided both in the central portion of the sheet-shaped coil 2 and a predetermined area around the conductor coil, or may be arranged only in the peripheral portion. After that, the exterior 14 may be formed in the same manner as in FIG.

By constructing such a structure,
It is possible to realize a thin inductance element having better inductance characteristics than the thin inductance element of FIG.

Next, FIG. 3 shows a metal thin film magnetic member 1 (1a ...
1h) is formed of a multi-layer structure of different kinds of metal thin film magnetic layers, and metal thin film magnetic layers having different magnetic properties or material compositions are alternately laminated, or crystalline and amorphous metal thin film magnetic layers are alternately formed. By stacking layers, magnetic characteristics such as DC superposition characteristics and frequency characteristics can be designed and improved to desired characteristics, and it becomes possible to realize a thin inductance element having optimum characteristics and dimensions. Further, different kinds of metal thin film magnetic layers may be vertically symmetrically stacked, or may be arranged asymmetrically. The method of forming the member 1 is the most effective. Then, the exterior 14 may be formed in the same manner as in FIGS.

The thin inductance element shown in FIGS. 1 to 3 is about 2 to 20 mm square and has a thickness of 0.2 to 1 mm.
A rectangular plate-shaped inductance element having a very small thickness is assumed, but another shape such as a disk shape may be used.
Further, the thin inductance elements shown in FIGS. 1 to 3 are examples of the structures of the present invention, and the present invention is not limited to these structures.

As described above, the thin magnetic element of the present invention has at least the sheet-shaped coil 2 including the metal thin film magnetic member, the conductor coil 3 and the resin insulating portion 4. Hereinafter, each configuration of and will be described in detail.

Metal thin film magnetic member In the case of the thin magnetic element of the present application, since the cross-sectional dimension of the magnetic material above and below the coil in the thickness direction becomes extremely thin, the magnetic characteristics,
In particular, it is difficult to satisfy the DC superposition characteristics. In order to realize this, a magnetic material having a high saturation magnetic flux density and a magnetic permeability equal to or higher than a certain level is essential even if it is thin, and as a magnetic material capable of realizing a high saturation magnetic flux density, the main composition is F
It is preferable that the metal thin film magnetic member 1 is composed of e, Co and Ni, and the total content of Fe and Co is 50 wt% or more. Further, it does not matter whether the formed metal thin film magnetic member 1 has a crystalline structure, an amorphous structure, a nano crystallite, or a granular structure. The reason why the metal thin film magnetic member 1 has a layered structure of different metal thin film magnetic layers or a layered structure of a crystalline metal magnetic thin film layer and an amorphous metal magnetic thin film layer is a vortex at high frequency, although the reason is not clear. It was found that it is effective in reducing the current loss.

The thickness of the metal thin film magnetic member 1 varies depending on the frequency used, but is preferably 10 μm or more and 100 μm or less. This is because if it is too thick, the eddy current loss at high frequencies becomes large, and if it is too thin, the required permeability decreases. It is also conceivable that the foil-shaped or plate-shaped metal thin film magnetic member is formed by using an adhesive or the like above and below the resin insulating portion 4 of the sheet-shaped coil 2, but the warp, drop or heat shock of the board after the element is mounted. In some cases, the metal thin film magnetic member may be missing. Therefore, the plating method, the vapor deposition method, which can be directly formed on the resin insulating portion 4 of the sheet-shaped coil 2,
A construction method such as a sputtering method is preferable. Of these, a plating method is advantageous because a vacuum system is unnecessary, the deposition rate is fast, and the adhesion strength is strong. The plating method is roughly classified into an electroless plating method and an electrolytic plating method. Either method may be used, and in some cases, both methods may be used in combination without any problem.

Further, the high frequency characteristics of the thin magnetic element may be improved by imparting magnetic anisotropy during the formation of the metal thin film magnetic member 1 or after the formation thereof by heat treatment in a magnetic field or the like. Further, it is more preferable to perform heat treatment at 150 ° C. or higher after forming the metal thin film magnetic member 1 to relieve stress and improve magnetic characteristics.

Sheet-shaped coil As the sheet-shaped coil 2, a coil having a required number of turns of a round wire, a rectangular wire, a foil wire or the like, plating, etching,
A coil produced by punching is used as the conductor coil 3,
By covering this with the resin insulating portion 4 and hardening it, it is possible to prevent the conductor coil 3 from being broken or short-circuited due to chucking during mounting of the thin magnetic element on the substrate, warping of the substrate after mounting, dropping, or the like. However, the resin insulating portion 4 is the metal thin film magnetic member 1
Since it is necessary that the magnetic permeability is smaller than that, it is more preferable to use a non-magnetic material. The resin insulation part 4 is composed of epoxy resin, phenol resin,
An insulating resin containing at least one kind of a polyimide resin, a silicone resin or a modified resin thereof is preferable.

Further, in order to have a low resistance value and a high inductance value, it is necessary to increase the space factor of the conductor coil 3. For that purpose, it is preferable that the coating of the conductor coil 3 with the resin insulating portion 4 is as thin as possible. Further, in order to realize a high space factor, a coil produced by winding or plating is more preferable. Furthermore, since it is desirable that the material of the conductor coil 3 has low resistance, it is preferable to use silver or copper. In addition, in order to form a hole in the resin insulating portion 4 in a predetermined area of the central portion of the planar conductor coil 3 or the peripheral portion of the conductor coil, it may be formed by a drill, a laser, a puncher or the like. Further, since the conductor coil 3 of the sheet-shaped coil 2 is a planar coil, a coil having a low DC resistance can be realized by using a thick conductive wire even if it has a thin structure.

Next, a specific method for manufacturing the thin magnetic element of the present invention will be described.

In the case where the thin magnetic element of the present invention has the structure shown in FIG. 1, a sheet-shaped coil 2 which is formed in a sheet shape in advance is prepared, and then the upper and lower sides of the sheet-shaped coil 2 are electrolessly plated,
After forming, for example, an Al, Cu thin film or a FeNiB-based magnetic thin film as a metal underlayer (not shown) by a sputtering method, a vapor deposition method or the like, the metal thin film magnetic members 1a, 1b having a predetermined thickness are formed by electrolytic plating. By forming it, a thin magnetic element can be easily manufactured. in this way,
Winding technology is not necessary.

It is also possible to manufacture by the method shown in FIG. First, as shown in FIG. 4A, a large-sized sheet 7 having a plurality of sheet-shaped coils 2 formed therein is prepared. Next, as shown in FIG. 4B, the resin insulating portion 4 in a predetermined area of the central portion of the conductor coil 3 and the peripheral portion of the conductor coil (hereinafter, referred to as a predetermined area around the coil) is punched, a laser beam machine, Remove with a drill. Then, the metal underlayer is formed on the upper and lower portions of the large-sized sheet 7 and on the inner portion of the removed central portion of the conductor coil 3 and the peripheral portion of the coil by electroless plating, sputtering, vapor deposition or the like. The metal underlayer may be non-magnetic, but it is more preferably a metal magnetic material.

The metal thin film magnetic member 1 can be selectively formed by forming a resist film on the upper and lower surfaces of the large-sized sheet 7 at a place where the metal thin film magnetic member 1 is not formed.

Thereafter, as shown in FIG. 4 (c), the metal thin film magnetic member 1 is formed above and below the sheet-shaped coil 2 and the portion where the resin insulating portion 4 is removed by electroplating (center portion, predetermined area around the coil). To form. After that, as shown in FIG. 4D, the large-sized sheet 7 is cut to expose the terminals or to form end face electrodes on the cut end faces to complete individual thin magnetic elements.

In the conventional method, since it was necessary to form a coil by winding, there was a problem that the mass productivity was poor and the cost was high. On the other hand, according to the method of the present embodiment, a large number of thin magnetic elements can be manufactured at once, so that it is possible to suppress the production cost by mass-producing at low cost.

As described above, in the manufacture of the thin magnetic element of the present invention, the metal thin film magnetic member 1 is formed on the upper and lower sides of the sheet-shaped coil 2 by using a thin film forming process such as a plating method, a sputtering method or a vapor deposition method. As a result, the thin magnetic element can be produced by a simple method with excellent productivity.

Next, a power supply module using the thin magnetic element of the present invention will be described.

FIG. 5 shows the configuration of a power supply module equipped with the thin magnetic element of the present invention. In this power supply module, the thin magnetic element 13 is arranged on the wiring board 8,
The wiring board 8 and the terminal portion 3b of the thin magnetic element 13 are connected by a connection via 9. The connection via 9 is provided at the center of the resin layer 10. Further, a semiconductor chip 11, chip components 12 such as resistors and chip capacitors, etc. are mounted on the surface of the wiring board 8 opposite to the surface on which the thin magnetic element 13 is arranged. Since this power supply module uses the thin magnetic element 13 according to the present invention, it has a low profile despite mounting other components (semiconductor chip 11, chip component 12, etc.) in the height direction, and it is a thin magnetic element. Since there is no other component in the arrangement plane of 13, the area is small.

Further, since the two terminal lead-out positions of the thin magnetic element 13 can be set to arbitrary peripheral positions by the coil pattern, the power supply module of the present invention is not limited to the configuration shown in FIG. The effect of being large is also obtained.

[0052]

EXAMPLES The thin magnetic element and the method for manufacturing the same according to the present invention will be specifically described.

Example 1 First, as the sheet-shaped coil 2, an outer diameter of 5 mmφ, an inner diameter of 0.5 mmφ,
A large-size sheet 7 was prepared in which a plurality of sheet coils 2 each having a thickness of 280 μm and a conductor diameter of about 100 μm and 16 turns of conductor coils 3 stacked in two layers were insulation-coated with a resin insulating portion 4. The sheet-shaped coil 2 is formed by coating the conductor coil 3 with a resin insulating portion 4 having a magnetic permeability smaller than that of the metal thin film magnetic member 1, and in the first embodiment, polyimide is used as a constituent material of the resin insulating portion 4. Resin was used.

Next, the sample No. with the magnetic characteristics shown in (Table 1) was formed by the sputtering method. 1-No. Fe, C having 9
The metal thin film magnetic member 1 having a composition of
It was formed on both sides of the sheet-shaped coil 2 so as to have a thickness of 25 μm. After that, heat treatment at 200 ° C. for 60 minutes,
A thin inductance element having a size of 5 mm square and a thickness of 0.4 m having the structure shown in FIG. 1 was manufactured. Metal thin film magnetic member 1
If it is exposed, there is a risk of reduced reliability and short circuit,
Only the terminal portion 3b was exposed, and the exterior 14 was insulation-coated with an epoxy resin. By forming the outer package 14, the insulation and reliability are further improved.

The characteristics of the thin inductance element thus obtained were measured at a frequency of 3 MHz and a DC superimposed current;
The inductance value was measured under the condition of 0.5A. The saturation magnetic flux density of the metal thin film magnetic member 1 was measured with a magnetic field of 15 kOe using a VSM (sample vibrating magnetometer), and the magnetic permeability was measured using a figure 8 coil at a measurement frequency of 3 MHz. .

From Table 1, when the metal thin film magnetic member 1 has a saturation magnetic flux density of 1.0 T or more and a magnetic permeability of 300 or more,
It can be seen that the inductor exhibits excellent characteristics with an inductance value of 3.0 μH or more. After mounting on the board, a drop test was conducted from a drop of 1.5 m, but no change in inductance value was observed before and after the drop test.

[0057]

[Table 1]

(Example 2) As the sheet-shaped coil 2, an outer diameter of 8 mmφ, an inner diameter of 4.0 mmφ and a thickness of 6 were formed by a plating method.
A sheet-shaped coil 2 was prepared in which a conductor coil 3 having two turns of 14 μm and a conductor diameter of about 230 μm and having a diameter of about 230 μm was insulation-coated with a resin insulating portion 4. The sheet-shaped coil 2 is formed by coating the conductor coil with a resin insulating portion 4 having a magnetic permeability smaller than that of the metal thin film magnetic member 1, and in the second embodiment, epoxy is used as a constituent material of the resin insulating portion 4. Resin was used.

Next, the resin insulating portion 4 was perforated and removed using a puncher at the central portion of the sheet-shaped coil 2 and a predetermined area around the coil. Then, an Al metal base is formed by electroless plating on the upper and lower sides of the sheet-shaped coil 2 and the inner wall portion of the resin insulating portion 4 which has been punched and removed.
Using this as an electrode, the Fe in the plating bath is electroplated.
Ion, Co ion, Ni ion, C ion, B ion, P ion, S ion, etc. were adjusted in proportion, and the sample No. 10-No. A metal thin film magnetic member 1 having a composition of 18 was obtained. The thickness of the magnetic film is 45-50 μm
Met. After that, heat treatment was performed at 150 ° C. for 60 minutes in a nitrogen atmosphere to produce a thin inductance element having a size of 8 mm square and a thickness of 0.7 mm shown in FIG.

With respect to the characteristics of the obtained thin inductance element, the inductance value was measured at a measurement frequency of 1 MHz and a DC superimposed current of 1.0 A. From (Table 2), F
It can be seen that when the total content of e and Co is 50 wt% or more, excellent properties are exhibited. The thin inductance element of the present embodiment is ultrathin, and by filling the central portion and a predetermined area around the coil with the metal thin film magnetic member, the inductance value is low even though the DC resistance of the coil is as low as 90 mΩ. Was large and the direct current superposition characteristics were also good. After mounting on the board, a drop test was conducted with a drop of 1.5 mm, but no change in inductance value was observed before and after.

[0061]

[Table 2]

(Example 3) As the sheet-shaped coil 2, an outer diameter of 4 mmφ, an inner diameter of 0.8 mmφ and a thickness of 3 were obtained by a plating method.
A sheet-shaped coil 2 was prepared in which a conductor coil 3 having two turns of 14 μm and a conductor diameter of 00 μm and a conductor diameter of about 80 μm was insulation-coated with a resin insulating portion 4. The sheet-shaped coil 2 is formed by coating the conductor coil with a resin insulating portion 4 having a magnetic permeability smaller than that of the metal thin film magnetic member 1. In the third embodiment, silicon is used as a constituent material of the resin insulating portion 4. Resin was used.

Next, by using electroless plating on the upper and lower surfaces of the sheet-shaped coil 2, the upper first layer metal thin film magnetic member 1a, which is an FeNiB type amorphous metal thin film magnetic layer, and the lower first layer.
A layer metal thin film magnetic member 1b is formed, and an upper second layer metal thin film magnetic member 1c and a lower second layer metal which are crystalline metal thin film magnetic layers are formed on the amorphous metal thin film magnetic layer by electrolytic plating. The thin film magnetic member 1d is formed. Similarly, the electroless plating method and the electrolytic plating method are repeated, respectively, and the upper third-layer metal thin film magnetic member 1e and the lower third-layer metal thin film magnetic member 1 are repeated.
f, the upper fourth-layer metal thin-film magnetic member 1g and the lower fourth-layer metal thin-film magnetic member 1h are laminated to form the final metal thin-film magnetic member 1 having a four-layer structure. At this time, the thickness of each layer was 10 to 20 μm. Then, heat treatment at 150 ° C. for 60 minutes in a nitrogen atmosphere,
A thin inductance element having a size of 3 mm square and a thickness of 0.6 mm having the structure shown in FIG. 3 was produced.

The characteristics of the obtained thin inductance element were 2.5 μH at a measurement frequency of 5 MHz and a DC superposition current of 1.0 A, which was excellent high frequency characteristics and good DC superposition characteristics. Example 3
In the above, the metal thin film magnetic member 1 laminated in four layers has been described, but the number of laminated layers may be any number, as long as it is at least two layers in each of the upper and lower layers.

After mounting on the board, a drop test was conducted from a drop of 1.5 m, but no change in inductance value was observed before and after.

[0066]

As described above, the thin magnetic element of the present invention is thin and has a structure in which the magnetic flux hardly crosses the coil conductor. Therefore, magnetic loss is small even at high frequencies, and a high inductance value is obtained. It is possible to provide a thin magnetic element that realizes low coil DC resistance, excellent DC superposition characteristics, and has high mechanical strength and excellent reliability that can withstand a drop test during or after mounting on a substrate.

Further, according to the method of manufacturing a magnetic element of the present invention, the step of individually winding the wires is not required, and therefore a large quantity can be collectively manufactured by a simple device. Further, the power supply module of the present invention has a low profile and a small area by using the magnetic element of the present invention, and is of great industrial value.

[Brief description of drawings]

FIG. 1 is a sectional view showing a thin inductance element which is an embodiment of a thin magnetic element of the present invention.

FIG. 2 is a sectional view of a thin inductance element of another example.

FIG. 3 is a sectional view of a thin inductance element of another example.

4A to 4D are process diagrams showing an embodiment of a method for manufacturing a thin magnetic element of the present invention.

FIG. 5 is a sectional view showing a structure of a power supply module according to an embodiment of the present invention.

[Explanation of symbols]

1 Metal thin film magnetic member 1a Upper first layer metal thin film magnetic member 1b Lower first layer metal thin film magnetic member 1c Upper second layer metal thin film magnetic member 1d lower second layer metal thin film magnetic member 1e Upper third layer metal thin film magnetic member 1f Lower third layer metal thin film magnetic member 1g Upper 4th layer metal thin film magnetic member 1h Lower 4th layer metal thin film magnetic member 2 sheet coil 3 conductor coil 4 Resin insulation part 5 Metal magnetic members 7 large format sheets 8 wiring board 9 connection via 10 resin layer 11 semiconductor chips 12 chip parts 13 Thin magnetic element 14 Exterior

Continued front page    (72) Inventor Osamu Inoue             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hiroyuki Handa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5E049 AA01 AA04 AA07 BA11 CC01                       GC01 HC01                 5E070 AB01 BA11 BB01

Claims (13)

[Claims] 1. A thin magnetic element in which a sheet-shaped coil including a conductor coil and a resin insulating portion and a metal thin film magnetic member having a magnetic permeability higher than that of the resin insulating portion are arranged so as to sandwich the sheet-shaped coil. 2. A sheet-shaped coil including a conductor coil and a resin insulating portion, and a metal thin-film magnetic member having a magnetic permeability higher than that of the resin insulating portion so as to sandwich the sheet-shaped coil, and the metal thin-film magnetic member. Is a thin magnetic element disposed at at least one location selected from the central portion and the peripheral portion of the sheet-shaped coil where no conductor coil exists between the metal thin film magnetic members. 3. The main composition of the metal thin film magnetic member is Fe, Co.
And Ni, and the total content of Fe and Co is 50
The thin magnetic element according to claim 1, wherein the thin magnetic element is at least wt%. 4. The thin magnetic element according to claim 1, wherein the metal thin film magnetic member has a laminated structure of different metal magnetic members. 5. The thin magnetic element according to claim 4, wherein the metal thin film magnetic member has a laminated structure of a crystalline metal magnetic thin film and an amorphous metal magnetic thin film. 6. The saturated magnetic flux density of the metal thin film magnetic member is 1.0.
The thin magnetic element according to claim 1, which has a magnetic permeability of T or more and a magnetic permeability of 300 or more. 7. The thin magnetic element according to claim 1, which is a metal thin film magnetic member having a thickness of 10 μm or more and 100 μm or less. 8. The conductor coil is a two-stage coil which is divided into two upper and lower stages and wound in a planar shape, and the upper and lower two-stage coils are connected to each other at the innermost peripheral portion. 2. The thin magnetic element according to any one of 1. 9. The thin magnetic element according to claim 1, wherein the resin insulating portion contains at least one kind of epoxy resin, phenol resin, polyimide resin, silicon resin, or modified resin thereof. 10. The thin magnetic element according to claim 1, wherein the sheet-shaped coil is provided inside or on the surface of the wiring board as a part of the wiring layer of the wiring board. 11. A thin magnetic element including a step of producing a sheet coil by incorporating a conductor coil in a resin insulating portion and a step of forming a metal thin film magnetic member in a predetermined shape by plating on and under the sheet coil. Production method. 12. A thin type including a step of producing a sheet coil by incorporating a conductor coil in a resin insulating portion, and a step of forming a metal thin film magnetic member in a predetermined shape on the upper and lower sides of the sheet coil by sputtering and vapor deposition. Magnetic element manufacturing method. 13. A power supply module comprising the thin magnetic element according to claim 1 and a semiconductor chip and a chip component mounted on a wiring board.