MULTILAYER SUBSTRATE, INTEGRATED MAGNETIC DEVICE, POWER SOURCE APPARATUS, AND MULTILAYER SUBSTRATE PRODUCTION METHOD

The multilayer substrate according to the present disclosure includes: a plurality of substrates in which conductors are wired; and an insulation material to which first insulation particles each having a first particle diameter are added. The multilayer substrate has a lamination structure such that, in two of the substrates adjacent to each other among the plurality of substrates having been laminated, the first insulation particles, each having the first particle diameter substantially the same as the interval between the conductors on the two substrates, are disposed so as to be respectively brought into contact with the conductors wired on the adjacent two substrates.

TECHNICAL FIELD

The present invention relates to a multilayer substrate, an integrated magnetic device, a power source apparatus, and a multilayer substrate production method, and more particularly to a multilayer substrate capable of forming a plurality of magnetic devices and a production method thereof, and an integrated magnetic device and a power source apparatus that use the multiplayer substrate.

BACKGROUND ART

In order to reduce a failure rate of a system that requires high reliability, a technique is employed in which hardware of the system is provided with a redundant structure. For example, a power source apparatus is provided with a redundant structure including two or more lines of power source circuits, and thus power can be supplied to the system by using a power source circuit in an operable line even when some of the lines of the power source circuits are stopped. With this, reliability of the system can be improved.

In a power source apparatus having a redundant structure including a plurality of lines, when power processing is in a balanced state, a power loss of a power device being used in each of power source lines is substantially uniform among the power source lines. As a result, a temperature rise of the power device can be kept low. Herein, the balanced state indicates a state in which all the power source lines operate normally and power dealt in all the power source lines is uniform.

In relation to the present invention, PTL 1 describes a coil structure body including a coil and an insulation sheet. PTL 2 describes an insulated converter in which a coil is formed by a multilayer substrate.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In the power source device including a plurality of power source lines, when some of the power source lines are stopped, the remaining operating power source line is required to supply power to a load. In this case, power dealt in one power source line is increased, and hence a temperature of a power device in the remaining power source line is increased. Thus, a temperature rise of the power device approaches an allowable limit of each device, and hence there may be a risk that a problem such as limitation of power dealt in the entire power source apparatus or increase in size of the power device is caused. In particular, when the power source device is used in the ocean or in outer space, a cooling means of the power device is limited. A temperature rise of the power device causes degradation of reliability of a system, and hence suppression of a temperature rise of the power device is regarded as a problem to be solved.

Further, in a case of a magnetic device used in a power source circuit, in a winding body being a main body of the magnetic device, a generation loss is increased in proportion to a square of a current as a dealt power is increased. Moreover, in order to form an efficient magnetic circuit, the magnetic device, in most cases, has a complex steric structure using a magnetic body and a winding body. In view of this, it is desired that the magnetic device be capable of performing efficient heat radiation.

FIG.15is a diagram illustrating a cross-section of a general multilayer substrate900to be used as a winding body. The multilayer substrate900includes a substrate901including a conductor911and a substrate902including a conductor912. The conductors911and912are electric wires each formed on the substrate901and the substrate902. Between the substrate901and the substrate902, a glass fiber921and a thermosetting resin931are present. The glass fiber921ensures dielectric strength between the conductor911and the conductor912. The thermosetting resin931bonds the substrate901and the substrate902.

Both materials of the glass fiber921and the thermosetting resin931being used in the configuration inFIG.15have relatively high thermal resistance as compared to metal. Thus, the multilayer substrate900has high thermal resistance, and thus there arises a problem that it is difficult to suppress a temperature rise of the magnetic device configured by using the multilayer substrate900.

OBJECT OF INVENTION

An object of the present invention is to provide a technique of enabling reduction in thermal resistance of a multilayer substrate.

Solution to Problem

A multilayer substrate according to the present invention includes:a plurality of substrates on which conductors are wired; andan insulation material to which first insulation particles each having a first particle diameter are added, whereina lamination structure is formed between two substrates adjacent to each other among the plurality of substrates being laminated, and, in the lamination structure, the first insulation particles each having the first particle diameter substantially matching with an interval between the conductors on the two substrates are arranged in such a way as to contact with the conductors wired on the two substrates adjacent to each other.

A method of producing a multilayer substrate according to the present invention is a method of producing a multilayer substrate including a plurality of substrates on which conductors are wired, and the method includes procedures of:selecting first insulation particles each having a first particle diameter, based on an interval between the conductors on the plurality of substrates being laminated;adding the first insulation particles to an insulation material; andlaminating the plurality of substrates with the insulation material.

Advantageous Effects of Invention

The present invention provides a technique of enabling reduction in thermal resistance of a multilayer substrate.

EXAMPLE EMBODIMENT

With reference to the drawings, example embodiments of the present invention are described below in detail. Aforementioned elements are denoted with the identical reference symbols in the example embodiments and the drawings, and overlapping description therefor is omitted.

First Example Embodiment

A magnetic device using a multilayer substrate is configured by combining a winding body and a magnetic body used as a core of the winding body. The winding body is produced by laminating substrates on which conductors are wired on surfaces with an adhesive. The adhesive is a material (insulation material) that insulates the facing substrates. A typical material of the conductors is copper. Copper has low electric resistance and low thermal resistance, and is relatively low in price. A typical insulation material is a thermosetting resin. In the present application, the “multilayer substrate” may also be referred to as a “lamination substrate”.

In the present example embodiment, description is made on the multilayer substrate used in the magnetic device.FIG.1is an example of a cross-sectional diagram of a multilayer substrate100of the first example embodiment of the present invention. The multilayer substrate100is a two-layer multilayer substrate in which substrates101and102forming two layers include facing conductors111and112. The conductors111and112are formed on the substrate101and the substrate102, respectively. The material of the substrates101and102is a glass epoxy resin, for example. For example, the conductors111and112are copper printed wires formed on the substrates101and102, respectively. Conductors may be wired on both the surfaces of the substrates101and102. The conductors111and112are connected via a through hole or the like between the substrates as appropriate in such a way that the conductors on the multilayer substrate100form the wiring bodies. The basic configuration in which the multilayer substrate forms the winding body is publicly known, and hence wiring of the winding body of the multilayer substrate is omitted in the description. Further, an example of an embodiment of the magnetic device using the winding body is described in the second example embodiment and thereafter.

In the multilayer substrate100, when the substrate101and the substrate102are laminated, a thermosetting resin131to which two kinds of ceramics particles121and122having different particle diameters are added is used as an adhesive. A particle diameter d of the ceramics particles121is smaller than a particle diameter D of the ceramics particles122. The particle diameter indicates an average diameter of the particles. The ceramics particles121each having a smaller particle diameter are added in such a way to prevent a significant loss in fluidity and filling ability of the thermosetting resin131filled between the substrate101and the substrate102. The particle diameter d is 1 μm or smaller, for example.

Further, when the ceramics particles122each having a particle diameter larger than that of the ceramics particles121are filled between the conductor111and the conductor112, a minimum distance between the conductor111and the conductor112is secured. For example, when the ceramics particles122each having the particle diameter D are added to the thermosetting resin131, the ceramics particles122are filled between the conductor111and the conductor112. Thus, the distance between the conductor111and the conductor112can be equal to or larger than D by adding the ceramics particles122to the thermosetting resin131. In other words, the particle diameter D of the ceramics particles122may be set in such a way to secure the minimum interval between the conductor111and the conductor112. Further, the particle diameter D may be equal to or larger than the interval required for insulation between the conductor111and the conductor112. The particle diameter D may be selected to substantially match with the interval between the conductors111and112in the multilayer substrate100. As the particle diameter D is increased, the distance between the conductor111and the conductor112is increased, and insulation performance is also improved. Meanwhile, as the particle diameter D is increased, the interval between the substrate101and the substrate102(in other words, the layer thickness of the thermosetting resin131) is increased, and thermal resistance of the multilayer substrate100is increased. Thus, the particle diameter D of the ceramics particles122is preferably reduced within a range that insulation performance between the substrates can be secured.

In this manner, the ceramics particles121and122having different particle diameters are added to the thermosetting resin131used in the multilayer substrate100. The thermosetting resin131to which the ceramics particles121and122are added is an example of the insulation material. When the substrates are laminated by using the thermosetting resin131described above, fluidity and filling ability of the thermosetting resin131are secured due to the ceramics particles121each having a smaller particle diameter. At the same time, the insulation distance between the substrates can be secured (in other words, insulation performance is secured) due to the ceramics particles each having a larger particle diameter.

In other words, with the configuration described above, the ceramics particles121each having a larger particle diameter can secure a substantially uniform insulation distance between the substrates, and hence a step of strictly adjusting the separation distance between the substrates can be omitted from the production steps of the multilayer substrate100. In other words, according to the multilayer substrate100, positioning between the substrates can be facilitated in the production steps, and hence an effect of improving productivity can be exerted.

At the time of producing the multilayer substrate100, the particle diameters of the ceramics particles121and122are selected according to fluidity and filling ability of the thermosetting resin131and insulation performance of the multilayer substrate100. The addition amount of the ceramics particles122is preferably an amount by which the ceramics particles122are sufficiently filled between the conductor111and the conductor112in the entire multilayer substrate100. Further, a ratio of a volume or a mass occupied by the ceramics particles121in the thermosetting resin131may be greater than a ratio of a volume or a mass occupied by the ceramics particles122in such a way to secure fluidity and filling ability of the thermosetting resin131.

When the addition amount of the ceramics particles121is increased, a larger amount of the thermosetting resin131can be replaced with the ceramics particles121. With this, thermal resistance of the multilayer substrate100can further be reduced, and a thermal expansion coefficient of the multilayer substrate100can also be reduced. Reduction in thermal resistance contributes to expansion of heat radiation capacity of the multilayer substrate100. Moreover, when the thermal expansion coefficient of the multilayer substrate100is reduced, a thermal expansion coefficient difference between the multilayer substrate100and a component of the multilayer substrate100that has a relatively small thermal expansion coefficient can be reduced. For example, when a ferrite core being a type of ceramics is used in the magnetic device using the multilayer substrate100, a thermal expansion coefficient difference between the ferrite core and the multilayer substrate100can be reduced. When the thermal expansion difference is reduced, a margin of a gap with respect to the multilayer substrate100can be reduced at the time of mounting the ferrite core. Further, stress due to a temperature change applied to a contact part between the ferrite core and the multilayer substrate100may be reduced. As a result, while avoiding disadvantageous influence of interference between these components due to a temperature change, size reduction and improvement of reliability of the magnetic device using the multilayer substrate100can be achieved.

The thermosetting resin131to which the ceramics particles121and122are added is used to bond the substrate101and the substrate102. Due to the ceramics particles122each having a larger particle diameter, the distance between the conductor111and the conductor112can be controlled easily and securely only by bonding the substrate101and the substrate102. Further, with the ceramics particles122, the distance between the substrates can be set to the minimum value required for insulation. As a result, the ratio of the volume and the mass occupied by the thermosetting resin131including the ceramics particles121and122in the entire multilayer substrate100is also reduced, and thermal resistance of the multilayer substrate100is also reduced. For example, in the magnetic device configured by using the multilayer substrate100including the plurality of winding bodies, even when only some of the winding bodies operate as the magnetic device, the entire multilayer substrate100is capable of efficiently radiating heat from the winding bodies, and hence a temperature rise of the winding bodies can be suppressed. This contributes to improvement of reliability of the magnetic device.

Alternative Configuration of First Example Embodiment

The multilayer substrate including the following elements can also exert the effect of the multilayer substrate100, that is, small thermal resistance. The reference symbols of the elements associated with those inFIG.1are denoted in the parentheses. Specifically, the multilayer substrate (100) includes the plurality of substrates (101and102) on which the conductors (111and112) are wired and the insulation material (131) to which the first insulation particles (122) each having the first particle diameter (D) are added. The multilayer substrate (100) has a lamination structure between the two substrates (101and102) adjacent to each other among the plurality of laminated substrates, the lamination structure in which the first insulation particles (122) are arranged to contact with the conductors (111and112) wired on the two substrates adjacent to each other. Here, the first insulation particles (122) each has the first particle diameter (D) that substantially matches with the interval between the conductors (111and112) on the two substrates.

In the multilayer substrate described above, the insulation particles (122) each having the first particle diameter that substantially matches with the interval between the conductors on the laminated substrates are added to the insulation material (131), and hence lamination can be performed with the predetermined interval between the substrates (101and102) only by laminating the substrate101and the substrate102. With this configuration, the multilayer substrate (100) in which the thickness of the insulation material is small (in other words, thermal resistance is reduced) can easily be produced. Thus, even when some of the components mounted on the multilayer substrate100generate heat, a local temperature rise of the component generating heat and the periphery thereof can be avoided.

FIG.2is a flowchart illustrating an example of a production method of the multilayer substrate of the alternative configuration described above. First, the first insulation particles (122) each having the first particle diameter (D) are selected based on the interval between the conductors (111,112) on the plurality of laminated substrates (Step S01 inFIG.2). Further, the first insulation particles (122) are added to the insulation material (131) (Step S02). Finally, the plurality of substrates (101,102) are laminated with the insulation material (131).

Modification Example of First Example Embodiment

FIG.3is a diagram illustrating an example of a cross-sectional diagram of a multilayer substrate100A. In the multilayer substrate100A, substrates103and104are laminated in addition to the substrates101and102of the multilayer substrate100. The thermosetting resin131to which the ceramics particles121and122are added as described inFIG.1is filled between the substrate101and the substrate102, between the substrate102and the substrate103, and between the substrate103and the substrate104. In this manner, the structure of the multilayer substrate100inFIG.1is applicable to the multilayer substrate100A having a larger number of layers. The number of turns of the winding body can be increased by multilayering the substrate. The number of layers in the multilayer substrate100A may be greater.

Second Example Embodiment

In the present example embodiment, description is made on an integrated magnetic device to be used in a power source apparatus having a redundant structure of two lines (in other words, “1+1”).

FIG.4is a diagram illustrating a configuration example of a power source apparatus800in which an integrated magnetic device of the present example embodiment is used. The power source apparatus800includes two power source circuits801and802. The power source circuits801and802transforms a DC voltage Vin that is input, and outputs a DC voltage Vout. For example, Vin is equal to 57 V, and Vout is equal to 12 V. Vout is supplied to a load, which is not depicted.

In general, the power source circuits801and802operates at the same time. Further, when a failure occurs to one of the power source circuits801and802, only the other power source circuit operates. For example, when a failure occurs to the power source circuit801, the power source circuit801stops output of the DC voltage Vout, and only the power source circuit802outputs the DC voltage Vout. In this manner, the power source apparatus800has the “1+1” redundant structure including the two lines of power source circuits (the power source circuit801and the power source circuit802).

The power source circuit801includes one insulation transformer T1 and one smoothing inductor L1 inside thereof. The configuration of the power source circuit802is similar to that of the power source circuit801, and the power source circuit802includes one insulation transformer T2 and one smoothing inductor L2. Hereinafter, the insulation transformer T1 and the insulation transformer T2 are denoted as a transformer T1 and a transformer T2, respectively. Further, the smoothing inductor L1 and the smoothing inductor L2 are denoted as the coil L1 and the coil L2, respectively. An integrated magnetic device201described later is an electric component acquired by integrating the four magnetic devices including the transformers T1 and T2 and the coils L1 and L2 that are used in the power source apparatus800. InFIG.4, the four magnetic devices surrounded by the broken line are included in one integrated magnetic device201.

FIG.5toFIG.8are diagrams illustrating examples of terminal arrangement of the transformers T1 and T2 and the coils L1 and L2, respectively.FIG.9is an example of a top diagram of a multilayer substrate251used in the integrated magnetic device201. Each of the transformers T1 and T2 and the coils L1 and L2 includes six terminals. In order to integrate the terminals, the multilayer substrate251includes twenty-four terminals252as illustrated inFIG.9.

With reference toFIG.9, winding bodies211and212associated with the transformers T1 and T2, respectively, and winding bodies213and214associated with the coils L1 and L2, respectively, are formed on one multilayer substrate251. The winding bodies211to214are formed within ranges of the multilayer substrate251, which are surrounded by the oval-shaped broken lines. At the center of the winding bodies211to214, ellipsoidal holes253passing through the multilayer substrate251are opened. As described later, magnetic bodies are inserted into those four holes253, and thus the winding bodies211to214exert predetermined functions as independent magnetic devices (in other words, as the transfers or the coils). The magnetic bodies inserted into the holes253are used as magnetic paths of the magnetic devices in longitudinal directions thereof.

FIG.10is an example of a top diagram and a side diagram of a magnetic body281used in combination with each of the winding bodies211to214. The magnetic body281is used as a core of each of the winding bodies211to214. A material of the magnetic body281is ferrite, for example. The magnetic body281is mounted to the multilayer substrate251in such a way to sandwich each of the winding bodies211to214from the front side and the back side. One ellipsoidal projection portion282of the magnetic body281is inserted into one hole253from the front side and the back side of the multilayer substrate251.

FIG.11is an example of a top diagram of the integrated magnetic device201. The four magnetic bodies281are mounted to the multilayer substrate251, and thus the multilayer substrate251functions as the integrated magnetic device201. A fixing means for the magnetic body281and the multilayer substrate251is not particularly limited, and an adhesive may be used, for example.

The lamination structure of the substrates of the multilayer substrate251is similar to that of the multilayer substrate100or100A of the first example embodiment described inFIG.1andFIG.3. In other words, the multilayer substrate251is a multilayer substrate including two or more layers in which the substrates are laminated in a direction orthogonal to the paper sheet by using the thermosetting resin131to which the ceramics particles121and122having different particle diameters are added. On one multilayer substrate251, the winding bodies211to214are configured by using the conductors by a known wiring method. The multilayer substrate251is produced by laminating the number of substrates that is calculated based on a specification of each of the transformers T1 and T2 and the coils L1 and L2. Similarly to the multilayer substrates100and100A of the first example embodiment, the four winding bodies211to214integrated on the multilayer substrate251are coupled at low thermal resistance.

The twenty-four terminals252are connected to terminals of the winding bodies211to214formed on the conductors of the multilayer substrate251, which are not depicted. The terminals252are terminals used at the time of mounting the transformers T1 and T2 and the coils L1 and L2 to a circuit substrate of the power source circuits801and802. Wiring of the conductors of the multilayer substrate251is designed in such a way that each of the terminals1to24inFIG.5toFIG.8is connected to any one of the twenty-four terminals252inFIG.9. An electric connection means between the terminals252and the circuit substrate of the power source circuits801and802is freely selective, and wiring is performed with a copper wire therebetween, for example. Not all the terminals1to24inFIG.5toFIG.8are required to be connected to the power source circuits801and802. Only a terminal required for achieving the functions of the power source circuits801and802may be connected to the power source apparatus800via the terminal252. In this manner, with the integrated magnetic device201using the multilayer substrate251, the functions of the transformers T1 and T2 and the coils L1 and L2 that are used in the power source circuits801and802forming the two lines can be exerted by one component.

When the power source circuits801and802normally operate, both the power source circuits801and802supply the DC voltage Vout to the load. Thus, power is consumed at all the transformers T1 and T2 and the coils L1 and L2. Thus, all the winding bodies are heat sources due to generation of a power loss. When one of the power source circuits801and802is stopped due to a failure or the like, the other power circuit that continues operating supplies, to the load, the power supplied from the power source apparatus800. In this case, the transformer and the coil of the operating power source circuit deal with power for the two power source circuits, and hence heat generation of the integrated magnetic device201is also concentrated on the transformer and the coil of the operating power source circuit. For example, when the power source circuit801is stopped, and only the power source circuit802operates, the transformer T1 and the coil L1 do not generate heat, and an amount of heat generation of the transformer T2 and the coil L2 (in other words, an amount of heat generation of the winding bodies213and214) is significantly increased. Even in this case, because the substrates of the multilayer substrate251of the integrated magnetic device201are laminated at low thermal resistance, heat generated by the transformer T2 and the coil L2 efficiently propagates through the entire multilayer substrate251, and the heat can be radiated from the entire integrated magnetic device201. As a result, even when only the power source circuit802operates, heat is prevented from being generated only in the vicinity of the transformer T2 and the coil L2, and a local temperature rise of those magnetic devices can be suppressed.

For size reduction of the integrated magnetic device201and uniform heat distribution in the magnet devices, smaller distances between the winding bodies211to214are better. However, when the distance between the winding bodies is too small, a magnetic flux leaking from a magnetic path of a winding body is mixed into a magnetic path of another adjacent winding body, which may disadvantageously influence operations of the winding bodies. To avoid such disadvantageous influence, the winding bodies are preferably arranged in such a manner that the magnetic paths of the adjacent winding bodies are orthogonal to each other. On the multilayer substrate251, the magnetic paths of the magnetic bodies281are orthogonal to each other for the adjacent winding bodies. For example, the magnetic path of the transformer T1 (the winding body211) and the magnetic paths of the coil L1 (the winding body212) and the coil L2 (the winding body213) are orthogonal to each other. With such arrangement, unnecessary power propagation or mixing of noise due to a magnetic flux leaking from an adjacent magnetic device can be suppressed.

As described above, in the integrated magnetic device201, the transformers T1 and T2 (insulation transformers) and the coils L1 and L2 (smoothing inductors) used in the power source circuits801and802are integrated. Further, the substrates forming the multilayer substrate251of the integrated magnetic device201are laminated at low thermal resistance as described in the first example embodiment. Thus, in the integrated magnetic device201, heat generated by the magnetic devices of the operating power source circuit can propagate through the entire integrated magnetic device201at low thermal resistance. As a result, the heat generated inside the integrated magnetic device201is dispersed to the entire integrated magnetic device201at low thermal resistance, and hence a local temperature rise of the magnetic devices used in the power source circuit can be suppressed.

Modification Examples of Second Example Embodiment

FIG.12is an example of a top diagram and a side diagram of a block301provided to the multilayer substrate251. The multilayer substrate251may include the block301for further reduction in thermal resistance of the multilayer substrate251. The block301is metal having a substantially rectangular frame-like shape, and the material is aluminum, for example. The block301has a through hole302at the center thereof, and has four notches in such a way to avoid contact with the magnetic body281.

FIG.13is an example of a bottom diagram and a side diagram of the integrated magnetic device201including the block301. The block301thermally couples the plurality of winding bodies211to214, and thus further reduces thermal resistance of the multilayer substrate251. The multilayer substrate251and the block301are joined in the vicinities of the winding bodies211to214. For example, the multilayer substrate251and the block301may be joined by a metal composite, or may be joined by other means. The multilayer substrate251includes the block301, and thus a temperature rise of the magnetic devices mounted to the integrated magnetic device201can further be suppressed.

In the second example embodiment and the modification examples, description is made on a case in which the power source apparatus800has the “1+1” redundant structure including the power source circuits801and802. However, on the integrated magnetic device201, magnetic devices used in power source circuits forming a plurality of, specifically, three or more lines may be mix-loaded. In this case, even when a failure occurs to the power source circuits in one or more lines, and as a result, a heat generation amount of the magnetic devices of the power source circuits in the remaining lines is increased, the integrated magnetic device201is capable of efficiently radiating the heat of the magnetic devices in the operating lines.

The magnetic devices mounted to the integrated magnetic device201are not limited to the transformers and the coils, and the number of magnetic devices is not limited to four. Moreover, even when an electric device other than the magnetic device is mounted to the multilayer substrate251, a temperature rise of the electric device due to heat generation of the electric device can be suppressed because the multilayer substrate251has low thermal resistance.

Third Example Embodiment

FIG.14is a diagram illustrating a configuration example of an integrated magnetic device830of the third example embodiment of the present invention.FIG.14illustrates an example of a top diagram of the integrated magnetic device830and an example of a cross-sectional diagram taken along the line A-A′ of the top diagram. The integrated magnetic device830includes one multilayer substrate810and two magnetic bodies820. The multilayer substrate810includes two winding bodies811and812. Each of the winding bodies811and812is formed by a conductor formed on each layer of the multilayer substrate810. Each of the winding bodies811and812is combined with the magnetic body820, and thus operates as an independent magnetic device. For example, the magnetic device is a transformer or a coil, but is not limited thereto. As the magnetic bodies820, two magnetic bodies281illustrated inFIG.10may be used for each of the winding bodies811and812.

The multilayer substrate810is produced by a lamination method similar to that of the multilayer substrate100or100A illustrated inFIG.1orFIG.3, and is produced by laminating the plurality of substrates with the insulation material. For example, the insulation material is a resin to which insulation particles are added, the insulation particles each having a particle diameter selected based on an interval between the conductors forming the winding bodies between the substrates of the multilayer substrate810.

In the integrated magnetic device830thus configured, the plurality of magnetic devices are integrated on one multilayer substrate810. Further, the plurality of substrates forming the multilayer substrate810are laminated by using the resin to which the insulation particles each having the particle diameter selected based on an interval between the conductors forming the winding bodies. By using such a resin, the multilayer substrate having low thermal resistance and high insulation performance can easily be produced. Further, the integrated magnetic device830is capable of dispersing generated heat to the entire integrated magnetic device830. Thus, even when any one of the plurality of the magnetic devices does not operate, the integrated magnetic device830is capable of suppressing a temperature rise of the operating magnetic device.

The whole or a part of the example embodiments described above can be described as, but not limited to, the following supplementary notes.

A multilayer substrate, including:a plurality of substrates on which conductors are wired; andan insulation material to which first insulation particles each having a first particle diameter are added, whereina lamination structure is formed between two substrates adjacent to each other among the plurality of substrates being laminated, and, in the lamination structure, the first insulation particles each having the first particle diameter substantially matching with an interval between the conductors on the two substrates are arranged in such a way as to contact with the conductors wired on the two substrates adjacent to each other.

The multilayer substrate according to Supplementary Note 1, wherein, in the insulation material, a ratio of second insulation particles is greater than a ratio of the first insulation particles, the second insulation particles each having a second particle diameter smaller than the first particle diameter.

The multilayer substrate according to Supplementary Note 1 or 2, wherein a material of the first insulation particles is ceramics.

The multilayer substrate according to any one of Supplementary Notes 1 to 3, further including a block thermally coupled to the conductors.

The multilayer substrate according to any one of Supplementary Notes 1 to 4, wherein the conductors form winding bodies.

An integrated magnetic device, including:the multilayer substrate according to Supplementary Note 5 including a plurality of the winding bodies; anda magnetic body in which the plurality of winding bodies are each arranged in such a way as to form a plurality of independent magnetic devices.

The integrated magnetic device according to Supplementary Note 6, wherein the plurality of magnetic devices include at least one of an insulation transformer and a smoothing inductor.

A power source apparatus having a redundant structure including a first line and a second line, the power source apparatus includingthe integrated magnetic device according to Supplementary Note 6 or 7, whereinone of the plurality of magnetic devices is used in the first line, andanother of the plurality of magnetic devices is used in the second line.

A method of producing a multilayer substrate including a plurality of substrates on which conductors are wired, the method including:selecting first insulation particles each having a first particle diameter, based on an interval between the conductors on the plurality of substrates being laminated;adding the first insulation particles to an insulation material; andlaminating the plurality of substrates with the insulation material.

The method of producing a multilayer substrate according to Supplementary Note 9, whereinthe first insulation particles each have the first particle diameter substantially matching with an interval between the conductors on two substrates adjacent to each other among the plurality of substrates being laminated, andthe multilayer substrate is formed by laminating the two substrates adjacent to each other for a plurality of times with the insulation material to which the first insulation particles each having the first particle diameter are added.

The method of producing a multilayer substrate according to Supplementary Note 9 or 10 wherein the plurality of substrates are laminated in such a way that the conductors form winding bodies.

While the invention has been particularly shown and described with reference to exemplary embodiments thereof, the invention is not limited to these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the claims. For example, the multilayer substrate and the integrated magnetic device given as examples in the example embodiments may be used in a transmitter, a receiver, a computer, and the like that have redundancy, in addition to the power source circuit. Further, even when the conductor of each of the substrates is other than the winding body, the configuration of each of the example embodiments enable efficient heat radiation from the conductor.

Further, the configurations of the example embodiments are not necessarily exclusive to each other. The actions and the effects of the present invention may be achieved by a configuration acquired by combining all or some of the above-mentioned example embodiments.

This application is based upon and claims the benefit of priority from Japanese patent application No. 2021-045546, filed on Mar. 19, 2021, the disclosure of which is incorporated herein in its entirety by reference.

REFERENCE SIGNS LIST