JP2002289419A - Sot magnetic alloy thick film, magnetic device, and method for manufacturing them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soft magnetic alloy thick film which has an excellent effect of attenuating noises of 100 to 400 MHz so as to meet an EMC standard. SOLUTION: The soft magnetic alloy thick film is formed of a multilayered thick film which is formed through a method in which sintered soft magnetic alloy layers of 0.5 to 5 μm in each thickness and obtained by sintering flat soft magnetic powder or soft magnetic ultra fine powder of permalloy (Fe-Ni alloy), sendust (Fe-Si-Al alloy), Fe-Si alloy, Fe-Co-Ni alloy or the like are laminated through the intermediary of an insulating layer. The sintered soft magnetic alloy layer is manufactured trough a method which comprises a process of mixing and dispersing flat soft magnetic alloy powder or soft magnetic ultra fine powder of 0.1 to 0.8 μm in each thickness or diameter and a binder into a solvent for the formation of a slurry, a process of applying the slurry onto a base material through a doctor blade method or a bar coater for the formation of a coating film, and a process of sintering the coating film at a high temperature (600 to 1400 deg.C) after the removal of the binder succeeding to the abruption of the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a soft magnetic alloy thick film which can be suitably used for noise suppression at 00 MHz to 400 MHz (for example, a magnetic core for a noise filter, etc.), a magnetic element using the same as a magnetic core, and a method of manufacturing them.

[0002]

2. Description of the Related Art With the increase in the frequency and performance of digital electronic equipment, EMI countermeasures against EMC standards around 200 MHz have become important issues. Ferrite core materials and chip components are widely used as EMI suppression components. However, recently, further improvement in characteristics has been required due to higher frequency and higher capacity,
It is difficult to obtain desired noise attenuation characteristics with a ferrite having a Snook limit curve.

As a known technique, first, Japanese Patent Application Laid-Open No. 56-819
In the publication No. 17, a molded body obtained by alternately laminating a high magnetic permeability alloy powder layer and a non-conductive ceramic powder layer is punched and sintered in a ring shape, but the thickness is not mentioned.
In addition, the shape is limited to a ring shape, and winding must be performed around the core, which is not suitable for miniaturization.

On the other hand, JP-A-5-62851 discloses that
A high-permeability magnetic core is disclosed in which a molded body in which high-permeability alloy powder layers and non-conductive ceramic powder layers are alternately laminated is sintered to reduce eddy current loss and improve high-frequency permeability. . In this publication, in order to reduce eddy current loss of a transformer core used at a high frequency of about 1 MHz, a high-permeability alloy thin plate having a thickness of 20 μm or less is manufactured using a plastic film film forming method, In order to reduce the thickness, it is possible to use a sheet thickness of 10 μm or less by using the distraction method.
In the range of 00 MHz to 400 MHz, it is necessary to make the soft magnetic alloy thin plate another thicker film. 20μm thin plate 2μ
In order to reduce the thickness to about m, even if the elongation method is used, it is necessary to perform rolling and heat treatment a plurality of times, which is extremely expensive and impractical.

In Japanese Patent Application Laid-Open No. H11-16733, lamination using foil is performed. However, it is inconvenient to reduce the thickness as described in the publication. It can be carried out. This is because a magnetic element used at a high frequency ideally has a structure in which a soft magnetic film and an insulating film are deposited in multiple layers.

As a method of laminating such thin films, film formation by a vacuum film formation method is also being studied. JP-A-3-2835
No. 14 discloses a method of forming a multilayer film composed of an amorphous metal magnetic material / insulator by a sputtering method using a reactive gas. This method uses silica, alumina,
Since oxides and nitrides such as silicon nitride can be used as the insulator of the multilayer film, and the soft magnetic layer also uses an amorphous material having a large electric resistance, excellent characteristics with a magnetic permeability of 5000 or more even at a high frequency of 100 MHz can be obtained. However, it is extremely difficult to manufacture a magnetic element having a thickness of several μm at a realistic price because it is difficult to perform vacuum film formation in a short time.

[0007]

SUMMARY OF THE INVENTION It is a first object of the present invention to overcome the above-mentioned problems and to provide a soft magnetic alloy thick film having an excellent noise attenuation effect of 100 MHz to 400 MHz which is a problem in satisfying the EMC standard. It is to provide a magnetic element.

A second object of the present invention is to provide a soft magnetic alloy thick film having an excellent noise attenuation effect of 100 MHz to 400 MHz and a soft magnetic alloy thick film capable of manufacturing a magnetic element at low cost, which are problems in meeting the EMC standard. And a method for manufacturing a magnetic element.

Other objects and novel features of the present invention will be clarified in embodiments described later.

[0010]

In order to achieve the above object, a soft magnetic alloy thick film according to the first aspect of the present invention comprises a sintered soft magnetic alloy layer having a thickness of 5 μm or less and an insulating layer alternately. It is characterized by being laminated in multiple layers.

A soft magnetic alloy thick film according to a second aspect of the present invention is characterized in that, in the first aspect, the thickness of the sintered soft magnetic alloy layer is 0.5 μm to 5 μm.

A soft magnetic alloy thick film according to a third aspect of the present invention is characterized in that, in the first or second aspect, the sintered soft magnetic alloy layer has a space portion of 1 to 50% by volume inside. And

According to a fourth aspect of the present invention, there is provided a soft magnetic alloy thick film according to the first, second or third aspect, wherein the insulating layer has a thickness of 5 μm.
The following oxide layer, nitride layer or organic layer is characterized.

According to a fifth aspect of the present invention, in the soft magnetic alloy thick film according to the first, second, third or fourth aspect, the sintered soft magnetic alloy layer has a carbon content of 0.05% by weight or less. It is characterized by.

According to a sixth aspect of the present invention, there is provided a method for manufacturing a soft magnetic alloy thick film, comprising mixing and dispersing a flat soft magnetic alloy powder having an average thickness of 0.1 to 0.8 μm with a binder and a solvent. After making it into a slurry and applying it to form a coating film,
The present invention is characterized in that a sintered soft magnetic alloy layer is produced by debinding and sintering, and a multilayer is formed by sandwiching an insulating layer having a thickness of 5 μm or less between the sintered soft magnetic alloy layers.

The method of manufacturing a soft magnetic alloy thick film according to the invention of claim 7 of the present application is as follows: a soft magnetic ultrafine powder having a diameter of 0.1 to 0.8 μm is mixed with a binder and a solvent and dispersed to form a slurry; After applying this to form a coating film, binder removal and sintering were performed to produce a sintered soft magnetic alloy layer, and a multilayer was formed with an insulating layer having a thickness of 5 μm or less interposed between the sintered soft magnetic alloy layers. It is characterized by:

The method of manufacturing a soft magnetic alloy thick film according to the invention of claim 8 of the present application is characterized in that, in claim 6 or 7, the sintering temperature is from 600 ° C. to 1400 ° C.

According to a ninth aspect of the present invention, there is provided a magnetic element, wherein a sintered soft magnetic alloy layer having a thickness of 5 μm or less and insulating layers are alternately and multi-layered to form a soft magnetic alloy thick film. The layer has a pattern area larger than the pattern area of the sintered soft magnetic alloy layer, and a conductor is provided in a through hole formed by the insulating layer.

According to the tenth aspect of the present invention, there is provided a magnetic element comprising:
In Claim 9, a through-hole group in which the through-holes are arranged close to each other is provided, and a pattern of the sintered soft magnetic alloy layer does not exist in a predetermined region surrounding the entire through-hole group. It is characterized by doing.

The magnetic element according to the invention of claim 11 of the present application is:
11. The method according to claim 9, wherein the thickness of the sintered soft magnetic alloy layer is 0.5 μm to 5 μm, and the insulating layer is an oxide layer, a nitride layer, or an organic layer of 5 μm or less. .

According to the method of manufacturing a magnetic element of the present invention, a nonmagnetic oxide powder is mixed with a binder and a solvent and dispersed to form a slurry, which is printed on a substrate in a predetermined pattern. Layer printing process, average thickness 0.1
軟 0.8 μm flat soft magnetic alloy powder or 0.8 μm in diameter.
A soft magnetic ultrafine powder of 1 to 0.8 μm is mixed with a binder and a solvent and dispersed to form a slurry, and the slurry is overlaid on the base material so as to be smaller than the pattern area of the insulating layer in the insulating layer printing step. A magnetic layer printing step of printing, and a sintering step of separating the base material from the laminate formed on the base material in the insulating layer printing step and the magnetic layer printing step, and sintering at a high temperature after debinding. A conductor forming step of providing a conductive paste in a through hole formed by the pattern in the insulating layer printing step.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a soft magnetic alloy thick film and a magnetic element according to the present invention and a method for manufacturing the same will be described below.

A thick film of a soft magnetic alloy will be described as a first embodiment according to the present invention. In the present embodiment,
The soft magnetic alloy thick film is made of permalloy (Fe-Ni alloy), sendust (Fe-Si-Al alloy), Fe-Si alloy,
A sintered soft magnetic alloy layer having a thickness of 0.5 to 5 μm obtained by sintering a flat soft magnetic powder or a soft magnetic ultrafine powder such as an Fe—Co—Ni alloy through an insulating layer having a thickness of 5 μm or less. It is composed of a multi-layer thick film that is laminated.

The sintered soft magnetic alloy layer is formed by mixing and dispersing a flat soft magnetic alloy powder or a soft magnetic ultrafine powder having a thickness or a diameter of 0.1 to 0.8 μm with a binder and a solvent to form a slurry. And a step of applying the slurry on a substrate by a doctor blade method or a bar coater to form a coating film, and sintering at a high temperature (600 to 1400 ° C.) after debinding after the substrate is stripped. It can be manufactured by the steps. Then, following the above-described sintered soft magnetic alloy layer manufacturing process, the laminated structure is formed by sandwiching an inorganic insulating material (oxide layer or nitride layer) or an organic insulating material (various resin layers) between the sintered soft magnetic alloy layers. Thus, a soft magnetic alloy thick film having a desired thickness can be manufactured.

The reason why the thickness of the sintered soft magnetic alloy layer is limited to 0.5 μm or more is that if the thickness is smaller than this, the magnetic alloy layer becomes island-like (island-like discontinuous) and the magnetic permeability Is significantly reduced. The reason for limiting the thickness of the sintered soft magnetic alloy layer to 5 μm or less is that if the thickness is larger than this, the eddy current increases and the magnetic permeability at high frequencies cannot be increased.

It is desirable that the sintered soft magnetic alloy layer has a carbon content of 0.05% by weight or less. As shown in Table 1 below, when the carbon content exceeds 0.05% by weight, the magnetic properties deteriorate.

[0027]

[Table 1]

The flat soft magnetic powder used for forming the sintered soft magnetic alloy layer can be produced by processing a substantially spherical atomized powder with a wet medium stirring mill. The aspect ratio of the flat soft magnetic powder is preferably about 5 to 100, and if the aspect ratio is too large, the surface after sintering becomes rough, which is not preferable. For thin coating, the thickness of the flat soft magnetic powder or the diameter of the soft magnetic ultrafine powder is important.
If it is larger than the above range, the variation of the film thickness after sintering becomes large and the magnetic permeability is deteriorated. On the other hand, when the thickness is less than 0.1 μm, the production of the magnetic powder is difficult and the handling becomes difficult.

As a method for coating the slurry containing the flat soft magnetic alloy powder or the soft magnetic ultrafine powder, a doctor blade method is suitable for flat powder, and a bar coater is used for ultrafine powder. Is preferred. In sintering after debinding, a space (usually 1 to
(Within a range of 50% by volume), but a sufficiently large magnetic permeability for practical use is obtained, which does not require pressurization for eliminating this space.

The sintering temperature after the binder removal is 600 to
A temperature range of 1400 ° C. is preferable. If the temperature is lower than 600 ° C., the binder may remain. If the temperature exceeds 1400 ° C., problems such as evaporation of the magnetic alloy occur, which is not preferable.

After the pressurization, a heat treatment for removing strain may be performed. This makes it possible to further reduce the thickness of the magnetic layer and at the same time reduce the space portion, so that it is somewhat expensive, but it is possible to improve the magnetic characteristics at high frequencies. is there.

It is desirable that the thickness of the inorganic or organic insulating layer sandwiched between the sintered soft magnetic alloy layers is 5 μm or less and as thin as possible. If the thickness is larger than 5 μm, the ratio of the magnetic layer to the soft magnetic alloy thick film formed by laminating the sintered soft magnetic alloy layer and the insulating layer is unpreferably reduced.

According to the first embodiment, 100 MHz to 400 MHz which is a problem in satisfying the EMC standard
In this frequency band, a complex magnetic permeability twice or more that of the ferrite core can be obtained, and the EMI suppression element can be reduced in size at a realistic price.

As a second embodiment according to the present invention, an example of a magnetic element using the soft magnetic alloy thick film as a magnetic core will be described. 1 and 2, reference numeral 1 denotes a magnetic core (core) having a predetermined thickness, which is formed of the soft magnetic alloy thick film described in the first embodiment. However, the pattern area of the insulating layer, which is a nonmagnetic layer, and that of the sintered soft magnetic alloy layer are different, and the pattern area of the insulating layer 2 is, as shown in FIG. The pattern area of the insulating layer 2 is larger than the pattern area of the layer 5, and the pattern of the insulating layer 2 includes two through-hole groups in which a plurality of through-holes 3 are arranged in a straight line close to each other.
It is formed in places. As shown in FIG. 2B, in the sintered soft magnetic alloy layer 5, a rectangular region (window) 6 where the sintered soft magnetic alloy layer does not exist in order to avoid two through-hole groups.
Are formed at two places. Then, as shown in FIG. 2 (C), the insulating layer 2 and the sintered soft magnetic alloy layer 5 are alternately formed and sintered as will be described later in the description of the manufacturing method. Get. Here, the insulating layer is arranged on the upper and lower surfaces of the magnetic core 1.

As can be seen from FIG. 2C, each through-hole 3 is formed of the insulating layer 2 so that the pattern of the sintered soft magnetic alloy layer 5 does not contact the through-hole 3 and each through-hole 3 is formed. Are not individually surrounded by the sintered soft magnetic alloy layer (the entire through hole group is entirely surrounded by the sintered soft magnetic alloy layer). This is because when a region (window) where a sintered soft magnetic alloy layer does not exist is formed for each through hole and the sintered soft magnetic alloy layer surrounds the entire periphery of the through hole for each hole. This is because loss increases.

In this manner, a soft magnetic alloy thick film core 1 having two through-hole groups in which the through-holes 3 are arranged in a straight line as shown in FIG. 1 is obtained. A coil conductor 10 helically wrapped around several turns is formed by connecting the through conductors 8 on the upper and lower surfaces of the magnetic core 1 with connection conductors 9 made of conductive paste. That is, the through holes belonging to the first through hole group are 3a, 3b, 3c, and the through holes belonging to the second through hole group are 3a ', 3a.
b ', 3c', the upper end of the through hole 3a-3
The through conductor portions 8 may be connected by the connection conductor portions 9 in the order of a 'upper end, 3a' lower end-3b lower end, 3b upper end-3b 'upper end, 3b' lower end-3c lower end, 3c upper end-3c 'upper end. When the terminal electrodes 4 are formed at both ends of the magnetic core 1, the lower end of the through hole 3 a is further connected to one terminal electrode 4 by the connection conductor 9, and the lower end of the through hole 3 c ′ is connected to the connection conductor 9.
Then, it is sufficient to connect to the other terminal electrode 4.

The method of manufacturing the magnetic element shown in FIG. 1 will be described in detail. The magnetic element is prepared by mixing a non-magnetic oxide powder with a binder and a solvent and dispersing the same into a slurry. An insulating layer (nonmagnetic layer) printing step (for example, the pattern in FIG. 2A) in which the slurry is pattern-printed on a substrate by a doctor blade method or a bar coater by a screen printing method (for example, the pattern of FIG. A step of preparing a magnetic slurry by mixing and dispersing a flat soft magnetic alloy powder or a soft magnetic ultrafine powder having a thickness of 1 to 0.8 μm with a binder and a solvent to form a slurry, and using the slurry to form a magnetic layer on the base material; A magnetic layer printing step (for example, the pattern shown in FIG. 2B) in which the pattern area is overlapped and screen printed so that the pattern area is smaller than the pattern area of the insulating layer; The base material is separated from the laminate formed on the base material in the magnetic layer printing step, the sintering step of sintering at a high temperature after debinding, and the through-hole formed by the pattern in the insulating layer printing step It can be manufactured by a conductor forming step of providing (filling) a conductive paste in the holes, and a connecting step of connecting between the through holes by screen printing, plating or the like of the conductive paste. By connecting the through holes to each other, it is possible to form a one-turn conductive wire or a spiral winding having a plurality of turns. For the connection, various film forming methods such as screen printing and plating are used as described above.

A third embodiment according to the present invention is another example of a magnetic element using a soft magnetic alloy thick film as a magnetic core,
A case of manufacturing a common mode choke having a pair of windings will be described. As shown in FIGS. 3A and 3B, a plurality of through holes are provided in a magnetic core 11 (upper and lower surfaces are insulating layers) made of a soft magnetic alloy thick film described in the first embodiment. Two through-hole groups are formed in which 13 are arranged in a straight line close to each other. Then, a conductor paste is provided in each through hole 13 to form a through conductor portion 18.
In FIG. 3A, the first half 20A is formed by connecting the left half of the through conductor 18 with the connection conductor 19A on the front and back of the magnetic core, and the right half of the through conductor 18 is formed on the front and back of the core. The second winding 20B is formed by being connected by the connection conductor 19B. Further, each of the windings 20A and 20B is led out to the terminal electrode 14 on the side surface of the magnetic core 11 via a connection conductor, whereby a common mode choke having a pair of windings is obtained.

The manufacturing method in this case is the same as that of the magnetic element of the second embodiment.

Hereinafter, the present invention will be described in detail with reference to examples.

Example 1 A 4% by weight Mo permalloy powder having an average particle diameter of 10 μm manufactured by a water atomizing method was mixed with toluene and pulverized with a horizontal medium stirring mill to obtain an average particle diameter of 12 μm.
m of flat powder was produced. As a result of observation by a scanning electron microscope (SEM), it was confirmed that the thickness of the flat powder was 0.1 to 0.8 μm. This powder, a urethane resin as a binder, polyvinyl butyral, and methyl ethyl ketone as a solvent were mixed and dispersed by a medium stirring mill, applied to a PET film as a base material having a thickness of 188 μm as a slurry, and dried. Apply the dried coating film to PE
The film was peeled off from the T film, debindered at about 600 ° C. in a tubular furnace, and sintered at 1200 ° C. to obtain a sintered soft magnetic alloy layer having a thickness of about 3 to 20 μm. From the cross-section observation and the measurement of the bulk density, 17-32%
It turns out that there is space. A multilayer film having a thickness of about 0.18 mm was formed by laminating 30 layers of a polyimide film as an insulating layer having a thickness of about 2 μm (adhesive material was used as necessary) on this sintered soft magnetic alloy layer (about 0.18 mm thick). However, in the comparative example, the number of laminations was reduced in order to have the same thickness.)

A sample was prepared by punching the multilayer film into a toroidal shape, and the frequency dependence of the complex magnetic permeability (real part μ ′, imaginary part μ ″) measured by the one-turn method is shown in FIG. From the figure, in the frequency band of 100 MHz to 400 MHz, when the thickness of the sintered soft magnetic alloy layer is 4.0 μm, the values of the real part μ ′ and the imaginary part μ ″ of the complex permeability are large, It turns out that it is preferable as a material.

Table 2 shows the measured complex magnetic permeability (real part μ ′, imaginary part μ ″) of each sample measured at 100 MHz.

[0044]

[Table 2] From Table 2, it can be seen that the samples having the thickness range (3 to 5 μm) of the sintered soft magnetic alloy layer according to the present invention have thicknesses of 7 μm and 20 μm.
It can be seen that they are remarkably superior to the comparative example of No. and the conventional ferrite core.

Example 2 Fe having an average particle size of about 0.4 μm
-Ni alloy ultrafine powder and acrylic resin as a binder,
Dibutyl phthalate, acetone as a solvent, and ethyl acetate are mixed and dispersed to form a slurry, which is applied to a PET film as a base material having a thickness of 188 μm with a bar coater,
Let dry. The dried coating film was peeled off from the PET film, debindered at about 600 ° C. in a tubular furnace, sintered at 1200 ° C., and had a thickness of 0.4 μm.
0.8 μm, 2 μm, 4 μm, 5 μm, 7 μm and 20
A μm sintered soft magnetic alloy layer was produced. A polyimide film as an insulating layer having a thickness of about 2 μm was affixed to this sintered soft magnetic alloy layer (adhesive material was used if necessary).
The layers were stacked to form a multilayer film having a thickness of about 0.18 mm (however, in the comparative example, the number of layers was reduced in order to have the same thickness).

A sample was prepared by punching the multilayer film into a toroidal shape, and the complex magnetic permeability (real part μ ′, imaginary part μ ″) measured at 100 MHz is as shown in Table 3 below.

[0047]

[Table 3] From Table 3, it can be seen that the samples in the thickness range of the sintered soft magnetic alloy layer according to the present invention (0.8 μm, 2 μm, 4 μm, 5 μm) are more practical than the comparative examples having the thicknesses of 7 μm and 20 μm. It was confirmed that excellent characteristics were exhibited at important frequencies.

(Example 3) A mixture was prepared by mixing and dispersing the flat powder prepared in Example 1, the Fe-Ni alloy ultrafine powder having an average particle diameter of about 0.4 µm, acrylic resin, dibutyl phthalate, acetone and ethyl acetate. A layer coated with a slurry by a bar coater and a layer coated with a slurry prepared by mixing and dispersing ultrafine alumina powder as a nonmagnetic oxide, acrylic resin, dibutyl phthalate, acetone, and ethyl acetate with a bar coater are alternately overlapped. And stack them. This was punched into a toroidal shape, debindered, and sintered to produce a sintered multilayer thick film toroid having a total thickness of 20 layers and a thickness of about 100 μm (a cross section is shown in FIG. 5). The complex magnetic permeability at 100 MHz of the sintered soft magnetic thick film measured by the one-turn method was as shown in Table 4 below.

[0049]

[Table 4] From Table 4, it can be seen that the sintered soft magnetic thick film of the present invention (Example 3), in which the sintered soft magnetic alloy layer has a predetermined film thickness, is more important for practical use than the ferrite core of the same volume. It was confirmed that excellent characteristics were exhibited.

Example 4 Alumina fine powder as a nonmagnetic oxide was mixed and dispersed with a urethane resin, polyvinyl butyral, and methyl ethyl ketone in a Red Devil mill.
A slurry was formed on a PET film having a thickness of 188 μm by pattern printing (for example, a pattern having through holes in FIG. 2A) and dried to produce an alumina green sheet. In addition, the average particle diameter of 1 produced by the water atomizing method was used.
0 μm of 4% Mo permalloy powder was mixed with toluene and pulverized with a horizontal medium stirring mill to produce a flat powder having an average particle diameter of 12 μm. From the result of SEM observation, it was confirmed that the thickness of the flat powder was 0.1 to 0.8 μm. This flat powder, urethane resin, polyvinyl butyral, and methyl ethyl ketone were mixed and dispersed by a red devil mill, and the slurry was overlaid on the above pattern to perform pattern printing (for example, a pattern having a window shown in FIG. 2B). The flat powder printing pattern at this time was patterned so as to be inside the pattern of the alumina green sheet so as not to contact the outside and the through holes of the alumina green sheet. The dried films are peeled off from the PET film, and are stacked in layers. Finally, the layers are stacked in layers, but the uppermost surface and the lowermost surface are stacked so as to be insulating layers. This was press-bonded by a press, debinding was performed at about 600 ° C. in a tubular furnace, and then sintered at 1200 ° C. to obtain a sintered soft magnetic alloy thick film core having a thickness of about 100 μm. A conductor is printed using a Ni-based paste on one of the core surfaces so as to enter the through-hole, and the other side is similarly printed. At this time, the conductor was printed so that the entire conductor was spirally formed through the through hole to obtain a coil. Of course, there is no problem if the conductor paste is printed before firing. 100M of the sintered soft magnetic thick film coil
The complex magnetic permeability at Hz is as shown in Table 5 below.

[0051]

[Table 5] According to Table 5, the present invention (Example 4) in which the sintered soft magnetic alloy layer has a predetermined thickness as compared with the ferrite core having the same volume.
It was confirmed that the sintered soft magnetic thick film exhibited excellent characteristics at practically important frequencies.

Example 5 Alumina fine powder was mixed and dispersed with a urethane resin, polyvinyl butyral, and methyl ethyl ketone using a red devil mill, and was printed as a slurry on a 188 μm-thick PET film by pattern printing (for example, as shown in FIG. 2A). (A pattern having holes) and dried to produce an alumina green sheet. Further, ultra-fine permalloy having an average particle diameter of 0.3 μm, urethane resin, polyvinyl butyral, and methyl ethyl ketone are mixed and dispersed in a red devil mill, and the slurry is superimposed on the above pattern to perform pattern printing (for example, a window shown in FIG. 2B). Pattern). The permalloy ultrafine powder printing pattern at this time was patterned so as to be inside the pattern of the alumina green sheet so as not to contact the outside and the through holes of the alumina green sheet. The dried films are peeled off from the PET film and stacked in multiple layers, and finally stacked in multiple layers,
The uppermost surface and the lowermost surface are formed of an alumina layer so as to form an insulating film. This is press-bonded with a press, debinding is performed at about 600 ° C. in a tubular furnace, and then sintered at 1200 ° C. to form a sintered soft magnetic alloy having a shape of 0.8 mm × 0.8 mm × 1.6 mm. A thick core was obtained. Print a conductor using a Ni-based paste so as to enter the through hole on one side of the core surface,
Printing is similarly performed on the opposite side. At this time, the conductor was printed so that the entire conductor was spirally formed through the through hole to obtain a coil. Of course, there is no problem if the conductor paste is printed before firing. Table 6 below shows the characteristics of the resistance R and the reactance X at 100 MHz of the sintered soft magnetic thick film coil obtained by measuring this, and the frequency characteristics of the resistance R and the reactance X are as shown in FIG. However, the characteristics of a coil using a ferrite core are also shown as comparative examples.

[0053]

[Table 6] According to Table 6 and FIG. 6, the sintered soft magnetic alloy layer of the present invention (Example 5) in which the sintered soft magnetic alloy layer has a predetermined film thickness as compared with the coil of the comparative example using the ferrite core having the same shape and the same number of turns. It was confirmed that the sintered thick-film coil having the soft magnetic thick film as a magnetic core exhibited excellent characteristics at frequencies that were important in practical use.

In Examples 4 and 5, the operation of screen-printing an insulating layer and a magnetic layer alternately on a PET film as a substrate was repeated a plurality of times to produce a multilayer laminate. After peeling, a plurality of multi-layered laminates may be stacked and pressed and integrated.

Although the embodiments and examples of the present invention have been described above, it is to be understood by those skilled in the art that various modifications and changes can be made within the scope of the claims without limiting the present invention. Would be self-evident.

[0056]

As described above, the soft magnetic alloy thick film according to the present invention comprises a sintered soft magnetic alloy layer having a thickness of 5 μm or less and an insulating layer alternately and multilayered. , A complex permeability of at least twice that of a ferrite core can be obtained in a frequency band of 100 MHz to 400 MHz, which is a problem in satisfying the EMC standard. In addition, by forming a magnetic element using the soft magnetic alloy thick film as a magnetic core, an EMI countermeasure element having an excellent noise attenuation effect can be manufactured at a realistic price and can be downsized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a magnetic element using a soft magnetic alloy thick film for a magnetic core according to a second embodiment of the present invention.

FIG. 2 is an explanatory diagram showing patterns of an insulating layer and a soft magnetic alloy layer of a magnetic element according to a second embodiment, and a state in which both are laminated.

FIG. 3 is a plan view and a side view showing another example of a magnetic element using a soft magnetic alloy thick film as a magnetic core according to a third embodiment of the present invention.

FIG. 4 is a characteristic diagram illustrating frequency characteristics of a complex relative magnetic permeability of the soft magnetic alloy thick film according to the first embodiment of the present invention, in comparison with those of a comparative example and ferrite.

FIG. 5 is a sectional view of a multilayer sintered thick film according to a third embodiment of the present invention.

FIG. 6 is a characteristic diagram showing frequency characteristics of resistance R and reactance X of a sintered soft magnetic film coil as a magnetic element according to a fifth embodiment of the present invention, in comparison with the case of a coil using a ferrite core. It is.

[Description of Signs] 1,11 Magnetic core 2 Insulating layer 3,13 Through hole 4,14 Terminal electrode 5 Sintered soft magnetic alloy layer 6 Area 7 Conductor paste 8,18 Through conductor 9,9A, 19B Connection conductor 10 Coil Conductor 20A, 20B winding

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichi Yamashita 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation F-term (reference) 4K018 AA08 AA26 AA30 BA15 BA16 BA20 BB01 BB05 BD01 CA07 CA33 CA44 DA03 DA11 JA40 KA32 KA43 5E041 AA00 BC08 BD01 HB14 NN05 NN18

Claims (12)

[Claims] 1. A soft magnetic alloy thick film characterized in that sintered soft magnetic alloy layers having a thickness of 5 μm or less and insulating layers are alternately and multi-layered. 2. The sintered soft magnetic alloy layer has a thickness of 0.5 μm.
The soft magnetic alloy thick film according to claim 1, having a thickness of from 5 to 5 m. 3. The soft magnetic alloy thick film according to claim 1, wherein the sintered soft magnetic alloy layer has a space portion of 1 to 50% by volume inside. 4. The soft magnetic alloy thick film according to claim 1, wherein said insulating layer is an oxide layer, a nitride layer or an organic layer having a thickness of 5 μm or less. 5. The soft magnetic alloy thick film according to claim 1, wherein the sintered soft magnetic alloy layer has a carbon content of 0.05% by weight or less. 6. A flat soft magnetic alloy powder having an average thickness of 0.1 to 0.8 μm is mixed with a binder and a solvent and dispersed to form a slurry, which is coated to form a coating film.
Debindering and sintering to produce a sintered soft magnetic alloy layer, and a multilayered soft magnetic alloy film comprising an insulating layer having a thickness of 5 μm or less interposed between the sintered soft magnetic alloy layers. Method. 7. A soft magnetic ultrafine powder having a diameter of 0.1 to 0.8 μm is mixed with a binder and a solvent and dispersed to form a slurry. The slurry is applied to form a coating film, and then a binder is removed. A method for producing a soft magnetic alloy thick film, characterized in that a sintered soft magnetic alloy layer is formed by sintering, and an insulating layer having a thickness of 5 μm or less is sandwiched between the sintered soft magnetic alloy layers. 8. The method for producing a soft magnetic alloy thick film according to claim 6, wherein the sintering temperature is from 600 ° C. to 1400 ° C. 9. A sintered soft magnetic alloy layer having a thickness of 5 μm or less and insulating layers alternately and multilayered to form a soft magnetic alloy thick film, and the insulating layer is formed of the sintered soft magnetic alloy layer. A magnetic element having a pattern area larger than a pattern area, wherein a conductor is provided in a through hole formed by the insulating layer. 10. A through-hole group in which the through-holes are arranged close to each other is provided, and a pattern of the sintered soft magnetic alloy layer does not exist in a predetermined region surrounding the entire through-hole group. The magnetic element according to claim 9. 11. The sintered soft magnetic alloy layer has a thickness of 0.5.
11 μm to 5 μm, and the insulating layer is an oxide layer, a nitride layer or an organic layer having a thickness of 5 μm or less.
The magnetic element according to any one of the preceding claims. 12. An insulating layer printing step of mixing a nonmagnetic oxide powder with a binder and a solvent and dispersing the slurry to form a slurry, and printing the slurry in a predetermined pattern on a base material; A flat soft magnetic alloy powder having a diameter of 0.8 μm or a soft magnetic ultrafine powder having a diameter of 0.1 to 0.8 μm is mixed with a binder and a solvent and dispersed to form a slurry. A magnetic layer printing step of overlapping and printing so as to be smaller than a pattern area of the insulating layer in the printing step, and the base material from the laminate formed on the base material in the insulating layer printing step and the magnetic layer printing step. Manufacturing a magnetic element, comprising: a sintering step of exfoliating and sintering at a high temperature after removing a binder; and a conductor forming step of providing a conductor paste in a through hole formed by a pattern in the insulating layer printing step. Method.