JP2008072071A - Common mode choke coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a common mode choke coil capable of coping with a wide signal frequency band. <P>SOLUTION: The common mode choke coil 10 comprises: an insulator layer 15; a pair of spiral coils 12a, 12b arranged opposingly inside; a pair of first magnetic bodies 18a, 18b laminated so that the insulator layer is sandwiched; and terminal electrodes 11a, 11b, 11c, 11d connected to the leading section of the coils formed on the surface. In the common mode choke coil 10, the insulator layer is made of nonmagnetic bodies 13 (13a, 13b) for covering the surface of the coils, and a second magnetic body 14 for covering the surface. The first magnetic body is made of a ferrite sintered body, and the second magnetic body is made of resin containing magnetic powder containing metal-based soft magnetic powder, thus restraining disturbance in signal waveform and reducing common mode noise in a signal frequency band of not more than 1 GHz and in a signal frequency band of more than 1 GHz. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a common mode choke coil that is interposed in a differential transmission line or the like to attenuate common mode noise.

  Common mode choke coils used in various electronic devices are roughly classified into a winding type and a non-winding type, and the non-winding type is mainly used in electronic devices with strong demands such as downsizing and thinning. As shown in FIG. 8, a non-winding type common mode choke coil is sandwiched between a pair of magnetic substrates 8a and 8b made of ferrite or the like and the magnetic substrates 8a and 8b as shown in FIG. The laminated body 5 includes the insulator layer 3 (3a, 3b, 3c, 3d), the coil conductor layers 2a, 2b, and the lead conductor layers 2c, 2d. It is made of a material such as polyimide resin or epoxy resin.

Japanese Patent Application Laid-Open No. 08-203737

In recent years, DVI using a signal frequency exceeding 1 GHz, which is higher than a signal frequency of 1 GHz or less, such as USB 2.0, IEEE 1394, and LVDS, which are conventional communication standards, with an increase in data amount and signal speed in various electronic devices. Communication standards such as HDMI have been proposed.
However, since the conventional non-winding type common mode choke coil uses ferrite or the like as the magnetic substrate, it hardly functions as a magnetic material at a signal frequency exceeding 1 GHz, and a noise suppressing effect cannot be obtained. There was a problem.

  An object of the present invention is to provide a common mode choke coil that solves the above-described problems and can cope with both a signal frequency of 1 GHz or less and a signal frequency exceeding 1 GHz.

In order to achieve the above object, the present invention provides:
(1) An insulator layer, at least a pair of spiral coils disposed inside the insulator layer so as to face each other, and a pair of first layers stacked so as to sandwich the insulator layer in the thickness direction In a common mode choke coil comprising: 1 magnetic body; and a terminal electrode formed on the surface of the first magnetic body and connected to a lead portion at the end of the coil.
The insulator layer is composed of a nonmagnetic material that covers the surface of the coil and a second magnetic material that covers the surface of the nonmagnetic material, the first magnetic material is composed of a ferrite sintered body, and the second magnetic material. The body is made of a magnetic powder-containing resin containing metallic soft magnetic powder. (... hereinafter referred to as first problem solving means)

One of the main forms of the common mode choke coil is
(2) The metallic soft magnetic powder in the magnetic powder-containing resin has a flat shape. (... hereinafter referred to as second problem solving means)

One of the other main forms of the common mode choke coil is
(3) The magnetic powder-containing resin is applied after covering the surface of the non-magnetic insulator layer covering the coil, and then cured. (... hereinafter referred to as third problem solving means)

  The operation of the first problem solving means is as follows. That is, the insulator layer includes a nonmagnetic material that covers the surface of the coil and a second magnetic material that covers the surface of the nonmagnetic material, the first magnetic material includes a ferrite sintered body, and the second magnetic material. The magnetic body is made of a magnetic body-containing resin containing metallic soft magnetic powder. For this reason, in each of the signal frequency band of 1 GHz or less and the signal frequency band exceeding 1 GHz, it is possible to reduce common mode noise while suppressing disturbance of the signal waveform.

  The operation of the second problem solving means is as follows. That is, since the metallic soft magnetic powder in the magnetic powder-containing resin has a flat shape, the apparent permeability μ ′ of the second magnetic body can be increased.

The operation of the third problem solving means is as follows.
That is, the magnetic powder-containing resin is cured after being applied so as to cover the surface of the nonmagnetic material covering the coil conductor. As a result, in the process of curing the magnetic powder-containing resin, the flat-shaped metallic soft magnetic powder has a more flat orientation, that is, along the surface of the nonmagnetic material covering the outer periphery of the coil conductor. It becomes easy to arrange. For this reason, when a current flows through the coil conductor, the magnetic flux along the outer periphery of the coil conductor becomes better, and the apparent permeability μ ′ of the magnetic powder-containing resin is further increased.

According to the coil component of the present invention, a common mode choke coil capable of suppressing common mode noise while suppressing disturbance of a signal waveform in each of a signal frequency band of 1 GHz or less and a signal frequency band exceeding 1 GHz is provided. be able to.
The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

  Hereinafter, a first embodiment of a common mode choke coil of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing an appearance of a common mode choke coil 10 according to the first embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 showing an internal structure of the common mode choke coil 10 according to the first embodiment. FIG. 3 is an exploded perspective view for explaining the internal structure of the main part of the common mode choke coil 10 of the above embodiment.

As shown in FIGS. 1 to 3, the common mode choke coil 10 according to the present embodiment includes an insulator layer 15 and at least a pair of spiral coils disposed inside the insulator layer 15 so as to face each other. The coils 12a and 12b, a pair of first magnetic bodies 18a and 18b stacked so as to sandwich the insulator layer 15 in the thickness direction, and formed on the surfaces of the first magnetic bodies 18a and 18b, The common mode choke coil 10 includes terminal electrodes 11a, 11b, 11c, and 11d connected to the lead portions 12c1, 12c2, 12c3, and 12c4. The insulator layer 15 includes a nonmagnetic body 13 (13a, 13b) that covers the surfaces of the coils 12a, 12b and a second magnetic body 14 that covers the surface of the nonmagnetic body 13 (13a, 13b). The first magnetic bodies 18a and 18b are made of a ferrite sintered body, and the second magnetic body 14 is made of a magnetic powder-containing resin containing a metallic soft magnetic powder.
In the common mode choke coil 10 of the present embodiment, the metal soft magnetic powder in the magnetic powder-containing resin has a flat shape.
Further, the common mode choke coil 10 of the present embodiment was cured after the magnetic powder-containing resin was applied so as to cover the surfaces of the nonmagnetic bodies 13 (13a, 13b) covering the coils 12a, 12b. Is.

More specifically, the pair of coils 12a and 12b of the common mode choke coil 10 according to the present embodiment includes two spiral coils 12a1 and 12a2, 12b1 and 12b2, respectively. One coil 12a is connected to the inner peripheral side of the spiral coil 12a1 and the inner peripheral side of the spiral coil 12a2 by a through-hole conductor (not shown). Similarly, in the other coil 12b, the inner peripheral side of the spiral coil 12b1 and the inner peripheral side of the spiral coil 12b2 are connected by a through-hole conductor (not shown). The spiral coils 12a1 and 12a2 of the one coil 12a and the spiral coils 12b1 and 12b2 of the other coil 12b are disposed so as to alternately face each other inside the insulating resin 13.
Then, a lead 12c1 on the outer peripheral side of one spiral coil 12a1 of the one coil 12a is connected to a terminal electrode 11a provided on the outer periphery of the common mode choke coil 10, and the other of the one coil 12a The lead conductor 12c3 on the outer peripheral side of the spiral coil 12a2 is connected to a terminal electrode 11c provided on the outer periphery of the common mode choke coil 10. Similarly, a lead conductor 12c2 on the outer peripheral side of one spiral coil 12b1 of the other coil 12b is connected to a terminal electrode 11b provided on the outer periphery of the common mode choke coil 10, and the other coil 12b. The other lead-out conductor 12c4 of the other spiral coil 12b2 is connected to a terminal electrode 11d provided on the outer periphery of the common mode choke coil 10.

  Next, a preferred embodiment of the coil is as follows. That is, as the material of the coils 12a and 12b, a metal having excellent conductivity, such as Ag, Pd, Cu, Al, or an alloy thereof can be used.

  Further, the coil 12a, 12b is preferably in the form of a layer, but is not limited to this, and may be in a linear form. Moreover, it is preferable that the said coil 12a, 12b is coat | covered with the nonmagnetic body 13 (13a, 13b).

  Next, a preferred embodiment of the flat metallic soft magnetic powder is as follows. That is, as the metal-based soft magnetic material, pure iron (Fe), carbonyl iron (Fe-C), silicon steel (Fe-Si), permalloy (Fe-Ni), permendur (Fe-Co), Supermalloy (Fe—Ni—Mo), permember (Fe—Ni—Co), Fe—Al alloy, Fe—Al—Si (preferably Sendust (common name)), and the like can be given. In order to increase the affinity of the flat metal soft magnetic powder with the resin, it is preferable to perform a chemical surface treatment using a silane coupling agent or the like.

The shape of the metal-based soft magnetic powder means that the aspect ratio is 2 or more when the ratio of the major axis dimension of the flat surface to the thickness dimension orthogonal to the flat surface is defined as the aspect ratio. The aspect ratio is preferably 2 to 60, and more preferably 10 to 30. As a result of the simulation, a magnetic powder-containing resin having a high apparent permeability μ ′ was obtained by using the metal-based soft magnetic powder having such an aspect ratio. On the other hand, when the aspect ratio of the magnetic powder is smaller than 2, the demagnetizing field of the magnetic powder increases, and the permeability μ ′ in the flat plane decreases.
Moreover, as a long-axis dimension of the flat surface of the said metal type soft magnetic powder, several hundred nm-30 micrometers are preferable.

  Further, as the chemical surface treatment of the metal-based soft magnetic powder, it can be appropriately selected from at least one of coupling agents such as titanate, silane, and aluminum. A silane coupling agent is more preferable in order to increase the affinity with the silane coupling agent.

  Next, a preferred embodiment of the resin used for the magnetic powder-containing resin is as follows. That is, the resin may be either a thermoplastic resin or a thermosetting resin. Examples of thermosetting resins include benzocyclobutene (BCB), epoxy resin, phenol resin, unsaturated polyester resin, vinyl ester resin, polyimide resin (PI), polyphenylene ether oxide resin (PPO), bismaleimide triazine cyanate ester Examples thereof include resins, fumarate resins, polybutadiene resins, and polyvinyl benzyl ether resins. Examples of thermoplastic resins include very low density polyethylene resin (VLDPE), low density polyethylene resin (LDPE), linear low density polyethylene resin (LLDPE), medium density polyethylene resin (MDPE), and high density polyethylene resin (HDPE). ), Polypropylene resin (PP), polybutene resin, polymethylpentene resin, polyvinyl alcohol resin, ethylene / vinyl alcohol copolymer, polyacrylonitrile, polyamide resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene sulfide resin, Examples include polyetheretherketone resins, isotactic polystyrene resins, liquid crystal polymers, and the like. In particular, epoxy resin, polyimide resin (PI), and benzocyclobutene (BCB) are highly reliable because of their low dielectric constant and low dielectric loss tangent, as well as excellent chemical resistance and low water absorption. Is preferable in that it can be secured.

  On the surface of the non-magnetic body 13 covering the outer periphery of the coils 12, 12a, 12a1, 12a2, 12b, 12b1, and 12b2, the magnetic powder-containing resin 14 is coated with a laminating method, an isostatic pressing method, a spray method, a roller transfer, or the like. It can be formed by a method or other means. Moreover, it is preferable that the magnetic powder-containing resin is applied to the surface of the non-magnetic body 13 by the spray method, the roller transfer method, or the like and then cured. According to this, the flat surface of the flat metallic soft magnetic powder is easily aligned along the surface of the non-magnetic body 13 covering the outer periphery of the coils 12, 121, 12a1, 12a2, 12b, 12b1, 12b2. Further, it is more preferable that a coating film is gradually overlapped on the surface of the non-magnetic body 13 by the spray method or the roller transfer method.

  Next, a preferred embodiment of the first magnetic body 18 (18a, 18b) is as follows. That is, the first magnetic body 18 (18a, 18b) is preferably made of a high-resistance ferrite sintered body such as Ni-Zn ferrite.

  Next, a manufacturing method of an example of the common mode choke coil 10 of the present embodiment will be described with reference to FIGS. 4 and 5 are cross-sectional views showing an example of a manufacturing process of the common mode choke coil 10 of the present embodiment.

  An example of a method for manufacturing the common mode choke coil 10 according to the present embodiment is a method for manufacturing a large number of common mode choke coils 10 at once.

  First, a through hole 102 for forming a via is formed in the base 101 corresponding to the nonmagnetic material 13a (FIG. 4A). As the base 101, a film having a predetermined thickness, a copper-clad laminate (RCC), or the same substrate as a flexible printed wiring board is used. BCB), an insulating resin such as polyimide, epoxy, or polyester is used as a material.

  Next, a coil pattern 103 is formed on both surfaces of the base 101 by a conductor pattern forming method such as plating, etching, printing, and an ink jet method (FIG. 4B). Is filled.

  Next, an insulating layer 104 corresponding to the second nonmagnetic material 13b is formed on both sides (FIG. 4C). This insulating layer 104 is formed by heat vacuum laminating, isostatic pressing, RCC or dry film insulating layer. If it is liquid, it is formed by laminating by a spin coat method, etc. Especially, the use of a thermal vacuum laminate is preferable because it suppresses the film thickness variation. Although used, the resin may be either a thermoplastic resin or a thermosetting resin.

  Next, through holes for forming vias are formed by the same procedure as described above, the coil pattern 105 is formed, and the insulating layer 106 is formed (FIG. 4D). Next, the through-hole 107 for filling the material for forming the second magnetic body 14 is formed by a chemical method such as etching (FIG. 4E).

  Next, the through-hole 107 is filled with the resin 108 for forming the magnetic powder-containing resin 14, and a plate-like ferrite sintered body as the first magnetic bodies 109 and 109 is bonded to both surfaces to obtain a laminated board. (FIG. 5F). The magnetic powder-containing resin forming material is made of a resin such as benzocyclobutene (BCB), polyimide, epoxy, or polyester mixed with a flat metal soft magnetic powder as a filler.

  Next, a laminated body is obtained by cutting this laminated board for each unit part (FIG. 5G). Finally, the common mode choke coil 10 is obtained by forming the terminal electrodes 11a, 11b, 11c, and 11d on the side surface of the laminate by vapor deposition, sputtering, electroless plating, dipping, barrel plating, printing, or the like.

  Next, examples of the common mode choke coil of the present invention will be described. As a magnetic powder used in the magnetic powder-containing resin of the second magnetic body 14 of the insulator layer 15, (A) a flat metal-based soft material having an aspect ratio of 10 and an average particle diameter of 20 μm, which has been surface-treated with a silane coupling agent The magnetic powder (Sendust), (B) spherical Ni—Zn ferrite powder having an average particle diameter of 20 μm, and (c) a nonmagnetic nonmagnetic material as the insulator layer, and the same manner as in the above embodiment As a result of producing the common mode choke coil 1 and measuring the frequency characteristic of the characteristic impedance, the characteristic impedance variation was small in the embodiment (A) of the present invention, whereas the comparative examples (B) and (C ), It was difficult to maintain transfer characteristics at a signal frequency exceeding 1 GHz (up to 2 GHz).

  In the above, in the embodiment (A) of the present invention, the magnetic flux passing through the first magnetic body 18 made of a ferrite sintered body is a characteristic of the common mode choke coil 10 at a signal frequency of 1 GHz or less (several hundred MHz). At a signal frequency exceeding 1 GHz (˜2 GHz), the magnetic flux passing through the second magnetic body 14 made of the magnetic powder-containing resin containing the metallic soft magnetic powder contributes to the characteristics of the common mode choke coil 10. It is thought that.

  For reference, apparent magnetic permeability with respect to frequency for each of the second magnetic body made of a magnetic powder-containing resin containing a metal-based soft magnetic powder, the magnetic powder-containing resin containing a ferrite magnetic powder, and a plate-like ferrite sintered body The result of measuring μ ′ is shown in FIG. From the figure, the apparent permeability μ ′ of the magnetic powder-containing resin containing the metal-based soft magnetic powder does not decrease to a point exceeding 1 GHz, whereas the apparent appearance of the ferrite powder-containing resin and the ferrite sintered body of the comparative example The magnetic permeability μ ′ has already been significantly reduced at 1 GHz or less.

  Next, a second embodiment of the common mode choke coil of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view for explaining the internal structure of the common mode choke coil 20 of the present embodiment.

As shown in FIG. 7, the common mode choke coil 20 of the present embodiment includes an insulator layer 25 and at least a pair of spiral coils 22 a disposed inside the insulator layer 25 so as to face each other. 22b, a pair of first magnetic bodies 28a and 28b stacked so as to sandwich the insulator layer 25 in the thickness direction, and formed on the surfaces of the first magnetic bodies 28a and 28b. A common mode choke coil 20 including terminal electrodes 21a, 21b, 21c, and 21d connected to the lead conductor. The insulator layer 25 includes a non-magnetic body 23 covering the surfaces of the coils 22a and 22b and a second magnetic body 24 covering the surface of the non-magnetic body 23. The first magnetic bodies 28a and 28b include The second magnetic body 24 is made of a ferrite sintered body, and is made of a magnetic powder-containing resin containing metallic soft magnetic powder.
Further, in the common mode choke coil 20 of the present embodiment, the metallic soft magnetic powder in the magnetic powder-containing resin has a flat shape.
In the common mode choke coil 20 according to the present embodiment, the magnetic powder-containing resin is applied after covering the surface of the nonmagnetic material 23 covering the coils 22a1 and 22a2, and then cured.
Specifically, a pair of coils 22a and 22b are disposed in a nonmagnetic nonmagnetic body 23 so as to face each other, and are flat metal soft magnetic powders that have been chemically surface-treated. The outer periphery of the non-magnetic body 23 is covered with a magnetic powder-containing resin made of the above, and the first magnetic bodies 28a and 28b made of a pair of plate-like ferrite sintered bodies are attached to the outside of the magnetic powder-containing resin. ing.

  More specifically, the pair of coils 22a and 22b of the common mode choke coil 20 according to the present embodiment includes two spiral coils 22a1 and 22a2, 22b1 and 22b2, respectively. One coil 22a is connected to the inner peripheral side of the spiral coil 22a1 and the inner peripheral side of the spiral coil 22a2 by a through-hole conductor (not shown). Similarly, in the other coil 22b, the inner peripheral side of the spiral coil 22b1 and the inner peripheral side of the spiral coil 22b2 are connected by a through-hole conductor (not shown). One spiral coil 22a2 of the one coil 22a and one spiral coil 22b2 of the other coil 22b are opposed to each other inside the nonmagnetic body 23 with the nonmagnetic body 23a interposed therebetween. It is arranged.

  The common mode choke coil 20 according to the present embodiment is different from the common mode choke coil 10 according to the first embodiment. That is, in the common mode choke coil 10 according to the previous embodiment, the one coil 12a has a spiral shape. The coils 12a1 and 12a2 and the spiral coils 12b1 and 12b2 of the other coil 12b are arranged so as to alternately face each other inside the non-magnetic body 13, whereas the common mode of the present embodiment In the choke coil 20, one spiral coil 22a2 of the one coil 22a and one spiral coil 22b2 of the other coil 22b sandwich the nonmagnetic body 23a inside the nonmagnetic body 23. The other configurations and the operational effects thereof are the same as those of the first embodiment. The description thereof is omitted because it is like.

  In each of the common mode chokes of the first and second embodiments, a layered coil is used as a coil. However, the present invention is not limited to this, and a coiled wire coil conductor coated with insulation is wound. There may be.

  The present invention can be applied to a common mode choke coil used in a wide frequency band.

It is a perspective view which shows the external appearance of 1st Embodiment of the common mode choke coil of this invention. It is sectional drawing of the AA line in the said FIG. 1 which shows the internal structure of the said 1st Embodiment. It is a disassembled perspective view for demonstrating the internal structure of the principal part of the said 1st Embodiment. It is a partial expanded end view which shows an example of the manufacturing method of the common mode choke coil of the said 1st Embodiment. It is a partial expanded end view which shows an example of the manufacturing method of the common mode choke coil of the said 1st Embodiment. It is a figure which shows the change of apparent permeability (micro | micron | mu) 'with respect to the frequency of the magnetic body used for an example of the common mode choke coil of this invention. It is sectional drawing which shows the internal structure of 2nd Embodiment of the common mode choke coil of this invention. It is a figure which shows an example of background art.

Explanation of symbols

10: Common mode choke coils 11a, 11b, 11c, 11d: Terminal electrodes 12a1, 12a2, 12b1, 12b2: Coil conductors 12c1, 12c2, 12c3, 12c4: Lead conductors 13, 13a, 13b: Non-magnetic material 14: Second Magnetic body 15: Insulator layer 18: First magnetic body 20: Common mode choke coils 21a, 21b, 21c, 21d: Terminal electrodes 22a1, 22a2, 22b1, 22b2: Coil conductors 23, 23a, 23b: Non-magnetic bodies 24 : Second magnetic body 25: insulator layer 28: first magnetic body

Claims (3)

An insulator layer, at least a pair of spiral coils disposed inside the insulator layer so as to face each other, and a pair of first magnetic layers stacked so as to sandwich the insulator layer in the thickness direction A common mode choke coil comprising: a body; and a terminal electrode formed on a surface of the first magnetic body and connected to a lead portion at an end of the coil.
The insulator layer is composed of a nonmagnetic material that covers the surface of the coil and a second magnetic material that covers the surface of the nonmagnetic material, the first magnetic material is composed of a ferrite sintered body, and the second magnetic material. A common mode choke coil characterized in that the body is made of a magnetic powder-containing resin containing metallic soft magnetic powder.   2. The common mode choke coil according to claim 1, wherein the metallic soft magnetic powder in the magnetic powder-containing resin has a flat shape.   2. The common mode choke coil according to claim 1, wherein the magnetic powder-containing resin is applied so as to cover a surface of a non-magnetic insulator layer covering the coil and then cured.

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