JP2007214381A - Inductance element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inductance element which can attain the sufficient improvement of a heat dissipation property and low impedance to a high frequency current. <P>SOLUTION: An inductance element 1 is provided with three lines of electric insulating core bodies 7 extended on an insulating board 2 along the longitudinal direction of coils 5, 5. The coils 5, 5 are formed by mutually connecting each plating layer 8 formed to cover each electrical insulating core body 7 by an electrolytic plating method. Consequently, the bottom side of the coils 5, 5 is irregular along the side surface and the top surface of the electrical insulating core body 7, and the top surface side of the coils 5, 5 is an arch-like irregular shape centered on each electrical insulating core body 7. Consequently, since a surface area of the coils 5, 5 is enlarged in the inductance element 1, it is possible to attain the improvement of the heat dissipation property of heat generated in the coils 5, 5 and low impedance to a high frequency current. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inductance element in which a conductor having a predetermined length is formed on a substrate.

As a technique related to the above field, for example, there is a high frequency coil described in Patent Document 1. In this conventional high frequency coil, the surface area of the conductive portion (contact area between the conductive portion and the insulating portion) is increased by forming the top surface of the coil provided on the substrate into a concave cross section.
JP-A-5-41321

  Increasing the surface area of the conductive portion is advantageous in that it can improve the heat dissipation of heat generated by energization, and can realize low impedance against high-frequency current having the characteristic of flowing on the surface of the conductor due to the skin effect. However, in the conventional high-frequency coil described above, since the shape of the coil on the substrate side is simply flat along the substrate, it cannot be said that the surface area is sufficiently increased. Therefore, there has been a demand for a technique that can sufficiently improve heat dissipation and reduce impedance with respect to high-frequency current.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an inductance element that can sufficiently improve heat dissipation and reduce impedance against high-frequency current.

  In order to solve the above problems, an inductance element according to the present invention is an inductance element formed by forming a conductor having a predetermined length on a substrate, and the substrate has an electrical insulating property extending along the longitudinal direction of the conductor. The core is formed, and the conductor is formed by a plating layer grown so as to cover the electrically insulating core by electrolytic plating.

  In this inductance element, since the conductor is formed so as to cover the electrically insulating core formed on the substrate, the surface area on the substrate side of the conductor is increased by the contact area between the electrically insulating core and the conductor. The area can be increased. Further, since the conductor is formed by growing the plating layer by the electrolytic plating method, the shape on the top side of the conductor can be formed, for example, in an arch shape, and the surface area on the top side of the conductor can be increased. As a result, in this inductance element, it is possible to sufficiently improve heat dissipation and reduce the impedance against high-frequency current.

  Moreover, it is preferable that the substrate is further formed with a seed layer extending along the longitudinal direction of the conductor, and the electrically insulating core is formed on the seed layer. In this case, since the electrically insulating core is separated from the substrate, the contact area between the conductor and the core can be increased. Therefore, it is possible to further improve the heat dissipation and lower the impedance against the high frequency current.

  In addition, the electrically insulating cores are formed in a plurality of rows, and the conductor is formed by connecting each of the plated layers grown so as to cover each electrically insulating core by the electrolytic plating method. Is preferred. With such a configuration, the surface area of the conductor can be further increased, and heat dissipation and impedance reduction with respect to high-frequency current can be further achieved.

  The aspect ratio of the electrically insulating core is preferably 0.1 or more. In this case, eddy current loss generated in the conductor can be suppressed. Thereby, it is possible to suppress the heat generation of the conductor itself, and the inductance characteristics can be improved.

  As described above, according to the inductance element according to the present invention, it is possible to sufficiently improve the heat dissipation and reduce the impedance with respect to the high-frequency current.

  Hereinafter, a preferred embodiment of an inductance element according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a plan view showing an inductance element according to the first embodiment of the present invention. As shown in FIG. 1, the inductance element 1 has a substantially square-shaped insulating plate (substrate) 2 having a side of several millimeters. The insulating plate 2 is a so-called flexible substrate, and is formed with a thickness of about 60 μm using, for example, a polyimide resin, and has flexibility enough to be bent.

  A circular opening 3 for inserting an inner leg portion (not shown) of a ferrite core that accommodates the inductance element 1 is formed at substantially the center of the insulating plate 2. Derived end electrodes 4 are formed at the respective corners on both sides of the insulating plate 2.

  Further, spiral coils (conductors) 5 and 5 surrounding the opening 3 are formed on both surfaces of the insulating plate 2. One end portions of the coils 5 and 5 on both sides are electrically connected to each other via a contact portion 6 provided on the peripheral edge of the opening 3, and the other end portions of the coils 5 and 5 are connected to one side of the insulating plate 2. The lead-out end electrode 4 provided on the other side and the lead-out end electrode 4 provided on the other side are respectively electrically connected.

  Therefore, when a predetermined voltage is applied between the leading end electrode 4 provided on one side of the insulating plate 2 and the leading end electrode 4 provided on the other side, the insulating plate 2 is formed on both surfaces. A current is generated between the coils 5 and 5.

  Here, the internal configuration of the coils 5 and 5 described above will be described with reference to FIG. FIG. 2 is a diagram showing a part of a section taken along line II-II in FIG.

  As shown in FIG. 2, a plurality of rows (three rows in this embodiment) of electrically insulating cores 7 are provided inside the coils 5 and 5. The electrically insulating core 7 is formed of ferrite containing a resin such as BT resin, for example, and extends on the insulating plate 2 along the longitudinal direction of the coils 5 and 5 while being separated from each other. . Further, the aspect ratio of each electrically insulating core 7, that is, the ratio between the height H and the width W of the electrically insulating core 7 is 0.1 or more (about 1.0 in the present embodiment). ing.

  On the other hand, the coils 5 and 5 are formed by connecting the plating layers 8 made of, for example, copper, which are grown so as to cover the respective electrically insulating nuclei 7 by electrolytic plating. The bottom surface side of the coils 5 and 5 has a concavo-convex shape along the side surface and the top surface of each electrically insulating core 7, and the top surface side of the coils 5 and 5 is connected to each electrically insulating core 7. It has an arch-shaped uneven shape in which the corresponding position protrudes.

  Next, a method for manufacturing the inductance element 1 described above will be described with reference to FIG.

  First, as shown in FIG. 3A, the insulating plate 2 is prepared. The insulating plate 2 is a polyimide resin having a thickness of 60 μm and has a flexibility that can be bent. The above-described circular opening 3 (not shown in FIG. 3) is already formed in the approximate center of the insulating plate 2.

  Next, as shown in FIG. 3B, electrically insulating cores 7 made of ferrite containing a resin such as BT resin are formed on both surfaces of the insulating plate 2. For pattern formation of the electrically insulating core 7, for example, screen printing or ink jet printing can be used, thereby providing three rows with respect to the formation lines (see FIG. 1) of the spiral coils 5 and 5. Each electrically insulating core 7 is extended along the forming line in a state of being separated from each other. Instead of ferrite, for example, a photosensitive resist may be formed on both surfaces of the insulating plate 2, and each electrically insulating core 7 having the above pattern may be formed by photolithography using a predetermined mask.

  After forming the electrically insulating core 7, as shown in FIG. 3 (c), the plating layers 8 made of copper are electrodeposited from the respective electrically insulating cores 7 by electrolytic plating. By proceeding with the electrodeposition of the plating layer 8, each plating layer 8 grows so as to cover each electrically insulating core 7. Then, when the plating layers 8 and 8 grown thickly around the adjacent electrically insulating core 7 are connected and integrated with each other, the coils 5 and 5 are formed on both surfaces of the insulating plate 2, and FIG. And the inductance element 1 shown in FIG. 2 is completed.

  In this inductance element 1, three rows of electrically insulating cores 7 extending on the insulating plate 2 along the longitudinal direction of the coils 5 and 5 are provided, and the coils 5 and 5 are formed by electrolytic plating. Each of the plating layers 8 grown so as to cover each electrically insulating core 7 is connected to each other. Thereby, the bottom surface side of the coils 5 and 5 has an uneven shape along the side surface and the top surface of each electrically insulating core 7, and the top surface side of each of the coils 5 and 5 is each electrically insulating core. It has an arch-shaped uneven shape in which a position corresponding to the body 7 protrudes.

  As a result, in this inductance element 1, since the surface area (contact area between the conductive portion and the insulating portion) of the coils 5 and 5 is increased, the heat dissipation of the heat generated in the coils 5 and 5 by energization can be improved. At the same time, it is possible to realize a low impedance for a high-frequency current having a characteristic of flowing on the surface of the conductor by the skin effect.

  Further, in the inductance element 1, since the aspect ratio of each electrically insulating core 7 is 0.1 or more, eddy current loss generated in the coils 5 and 5 can be suppressed. Thereby, it becomes possible to suppress the heat generation of the coils 5 and 5 themselves, and the inductance characteristics can be improved.

  The inductance element 1 described above can also be obtained by the following manufacturing method. That is, first, as shown in FIG. 4A, an insulating plate 2 is prepared, and then, as shown in FIG. 4B, an electrically insulating core 7 made of a resin containing palladium as a catalyst is prepared. It is formed on both surfaces of the insulating plate 2. The pattern of the electrically insulating core 7 is formed in the same manner as the embodiment shown in FIG. 3B by, for example, screen printing, ink jet printing, photolithography, or the like.

  After forming the electrically insulating nuclei 7, plasma treatment or UV treatment is performed on the surface of each electrically insulating nuclei 7, and palladium as a catalyst is deposited on the surface. Then, by electroless plating using a predetermined plating mask (not shown), as shown in FIG. 4C, the bottom made of, for example, copper (or silver) so as to cover the surface of the electrically insulating core 7 The formation 9 is selectively formed.

  Thereafter, the plating layer 8 is electrodeposited by starting with the base layer 9 by electrolytic plating, and the plating layers 8 and 8 grown thickly around the adjacent electrically insulating core 7 are connected together and integrated. As a result, the coils 5 and 5 are formed on both surfaces of the insulating plate 2, and the inductance element 1 shown in FIGS. 1 and 2 is completed.

[Second Embodiment]
Subsequently, a second embodiment of the inductance element according to the present invention will be described. In this embodiment, the electrically insulating cores 7 provided inside the coils 5 and 5 are separated from the insulating plate 2, so that the electrically insulating cores 7 are directly formed on the insulating plate 2. This is different from the first embodiment.

  That is, in the inductance element 10 according to the second embodiment, as shown in FIG. 5, the seed layers 11 extending along the longitudinal direction of the coils 5 and 5 are provided on both surfaces of the insulating plate 2, and three rows are formed. The electrically insulating core 7 extends on the seed layer 11 while being separated from each other along the longitudinal direction of the coils 5 and 5. The aspect ratio of each electrically insulating nucleus is about 1.0, as in the first embodiment.

  The coils 5 and 5 are formed by connecting the seed layer 11 and the plating layer 8 grown so as to cover each electrically insulating core 7 by electrolytic plating. Thereby, each electrically insulating core 7 is included in the bottom surface side of the coils 5, 5, and the top surface side of the coils 5, 5 is an arch where the position corresponding to each electrically insulating core 7 is recessed. The shape is uneven.

  When manufacturing such an inductance element 10, first, an insulating plate 2 is prepared as shown in FIG. Next, as shown in FIG. 6B, seed layers 11 made of, for example, copper are formed on both surfaces of the insulating plate 2. The seed layer 11 extends along the formation line (see FIG. 1) of the coils 5 and 5 so as to be slightly narrower than the coils 5 and 5 to be formed. For the formation of the seed layer 11, for example, screen printing, ink jet printing, or sputtering through a predetermined mask (not shown) can be used.

  After the seed layer 11 is formed, an electrically insulating nucleus 7 is formed on the surface of the seed layer 11 as shown in FIG. As in the first embodiment, for example, screen printing, ink jet printing, photolithography, or the like can be used for pattern formation of the electrically insulating core 7, thereby forming the spiral coils 5 and 5. (See FIG. 1) Three rows of electrically insulating cores 7 are provided, and each of the electrically insulating cores 7 extends along the forming line in a state of being separated from each other.

  After forming the electrically insulating core 7, as shown in FIG. 6 (d), the plating layers 8 are electrodeposited starting from the seed layer 11 by electrolytic plating. By proceeding electrodeposition of the plating layer 8, when the plating layers 8, 8 grown thickly around the adjacent electrically insulating core 7 are connected and integrated with each other, both sides of the insulating plate 2 are integrated. The coils 5 and 5 are formed, and the inductance element 10 shown in FIG. 5 is completed.

  In this inductance element 10, the seed layer 11 is interposed between the insulating plate 2 and each of the electrically insulating cores 7, so that the electrically insulating core 7 is separated from the insulating plate 2 and the coils 5 and 5. 5 is included on the bottom side. Therefore, in addition to the portions that contact the side surfaces and top surface of each electrically insulating core 7, the surface area of the coils 5, 5 is increased by the amount of contact with the bottom surface of each electrically insulating core 7. It becomes possible to do. Thereby, the improvement of the heat dissipation of the heat | fever which generate | occur | produces in the coils 5 and 5 and the impedance reduction with respect to a high frequency current can be implement | achieved more effectively.

  Also in the inductance element 10, since the aspect ratio of each electrically insulating core 7 is 0.1 or more, eddy current loss generated in the coils 5 and 5 can be suppressed. Thereby, it becomes possible to suppress the heat generation of the coils 5 and 5 themselves, and the inductance characteristics can be improved.

  The present invention is not limited to the above embodiment. For example, in each of the embodiments described above, a plurality of rows of electrically insulating cores 7 are provided, but one row of electrically insulating cores 7 may be provided. The material of the substrate is not limited to the above-described flexible substrate made of polyimide resin, and may be ferrite, for example. Moreover, it is not restricted to an insulating board | substrate, A metal plate may be sufficient.

It is a top view which shows the inductance element which concerns on 1st Embodiment of this invention. It is a figure which shows a part of II-II line cross section in FIG. It is a figure which shows the manufacturing method of the inductance element shown in FIG. It is a figure which shows another manufacturing method of the inductance element shown in FIG. It is a figure which shows a part of cross section of the inductance element which concerns on 2nd Embodiment of this invention. It is a figure which shows the manufacturing method of the inductance element shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 ... Inductance element, 2 ... Insulating board (board | substrate), 5 ... Coil (conductor), 7 ... Electrically insulating core, 8 ... Plating layer, 11 ... Seed layer.

Claims (4)

An inductance element formed by forming a conductor of a predetermined length on a substrate,
The substrate is provided with an electrically insulating core extending along the longitudinal direction of the conductor,
The inductance element, wherein the conductor is formed by a plating layer grown so as to cover the electrically insulating core by an electrolytic plating method. The substrate is further provided with a seed layer extending along the longitudinal direction of the conductor,
The inductance element, wherein the electrically insulating core is formed on the seed layer. The electrical insulating core is provided in a plurality of rows,
3. The inductance element according to claim 1, wherein the conductor is formed by connecting each of plating layers grown so as to cover the respective electrically insulating nuclei by an electrolytic plating method. . The inductance element according to claim 1, wherein an aspect ratio of the electrically insulating core is 0.1 or more.

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