JP4775174B2 - Coil component and manufacturing method thereof - Google Patents

Description

  The present invention relates to a coil component and a manufacturing method thereof.

In conventional coil components, a magnetic gap is formed inside a laminate in which a plurality of coil conductor patterns and a plurality of magnetic green sheets are alternately laminated in order to improve the decrease in DC superposition characteristics caused by magnetic saturation. It is known to do (see, for example, Patent Document 1). In the coil component described in Patent Document 1, a nonmagnetic ceramic layer is disposed at a substantially central position of the laminated coil component. The non-magnetic ceramic layer functions as a magnetic gap and relaxes magnetic saturation, thereby improving the DC superposition characteristics.
JP 2005-259774 A

  However, since the non-magnetic ceramic, which is a different material from the magnetic green sheet, is used in the coil component described in Patent Document 1, when the laminated body laminated from the magnetic green sheet and the non-magnetic ceramic is fired. In addition, the thermal contraction rate of the magnetic green sheet is different from the thermal contraction rate of the nonmagnetic ceramic, so that the shrinkage balance of the laminate is poor, and the fired sintered body is warped or cracked. Further, since a material different from that of the magnetic green sheet is used, it is necessary to newly provide a process for laminating different materials, and there is a problem that the number of manufacturing processes increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a coil component capable of improving the DC superposition characteristics with a simple structure and a manufacturing method thereof.

The coil component according to the present invention includes a plurality of conductors and a magnetic body, and has first and second main surfaces facing each other, and a coil configured by electrically connecting the plurality of conductors. A sintered body provided, a resin layer formed on the first main surface, and a magnetic body disposed on the first main surface via the resin layer, and one of the plurality of conductors. Two conductors are exposed on the first main surface.

In the coil component according to the present invention, one conductor is exposed on the first main surface of the sintered body composed of a plurality of conductors and a magnetic body, and a resin layer is provided between the first main surface and the magnetic body. It has been. This resin layer forms a magnetic gap and can suppress the occurrence of magnetic saturation. As a result, the DC superimposition characteristics can be improved. Further, since the magnetic body is disposed on the first main surface of the sintered body via the resin layer, the direct current superimposition characteristics can be improved with a simple structure.

  Preferably, the second main surface further includes a magnetic body disposed via the resin layer, and one conductor different from the conductor exposed to the first main surface among the plurality of conductors is the second main surface. Is exposed. In this case, by forming a magnetic gap also on the second main surface, magnetic saturation can be further suppressed, and the DC superimposition characteristics can be further improved.

The manufacturing method of the coil component which concerns on this invention consists of a some conductor and a magnetic body , has the 1st and 2nd main surface which mutually opposes, and a plurality of conductors are electrically connected. A coil is provided, and a sintered body preparing step of preparing a sintered body in which one of a plurality of conductors is exposed on the first main surface, and a magnetic substrate on the first main surface And a magnetic substrate bonding step for bonding with a resin.

In the method of manufacturing a coil component according to the present invention, a magnetic substrate is bonded with a resin to the first main surface of the sintered body, which is composed of a plurality of conductors and a magnetic body, and one conductor is exposed. The formed resin layer forms a magnetic gap and can relieve magnetic saturation. As a result, it is possible to easily manufacture a coil component that improves the DC superimposition characteristics.

The manufacturing method of the coil component which concerns on this invention consists of a some conductor and a magnetic body , has the 1st and 2nd main surface which mutually opposes, and a plurality of conductors are electrically connected. A sintered body preparing step of preparing a sintered body in which a coil to be configured is provided and one conductor of a plurality of conductors is exposed on the first main surface, and a first on the first main surface A resin layer forming step of forming a second resin layer containing magnetic powder on the first resin layer after forming the resin layer.

In the method of manufacturing a coil component according to the present invention, the first resin layer and the magnetic powder are included on the first main surface of the sintered body which is composed of a plurality of conductors and a magnetic body and one conductor is exposed. A second resin layer is sequentially formed. This first resin layer forms a magnetic gap and can relieve magnetic saturation. For this reason, the coil component which improves a direct current | flow superimposition characteristic can be manufactured easily.

  Preferably, the sintered body preparation step is a lamination step of obtaining a laminate by alternately laminating a plurality of conductor patterns and a plurality of magnetic green sheets so that one conductor pattern of the plurality of conductor patterns is exposed. And a step of firing the laminate. In this case, since the laminate is configured by laminating a plurality of conductor patterns and a plurality of magnetic green sheets, these magnetic green sheets have the same thermal contraction rate. For this reason, when baking a laminated body, the shrinkage balance of a laminated body is good and generation | occurrence | production of a curvature and a crack can be suppressed to a sintered compact.

  ADVANTAGE OF THE INVENTION According to this invention, the coil components which can improve a direct current | flow superimposition characteristic with a simple structure, and its manufacturing method can be provided.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent components are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
With reference to FIG.1 and FIG.2, the structure of the coil component 1 which concerns on 1st Embodiment is demonstrated. FIG. 1 is a perspective view showing a coil component according to the first embodiment. FIG. 2 is a view for explaining a cross-sectional configuration of the coil component according to the first embodiment.

  The coil component 1 includes a sintered body 13 having a substantially rectangular parallelepiped shape, and a pair of terminal electrodes 11 and 12 formed on both end faces of the sintered body 13 in the longitudinal direction. The sintered body 13 has a first main surface 13a and a second main surface 13b facing each other. A magnetic substrate (magnetic body) 14 is arranged on the first main surface 13 a side of the sintered body 13. The magnetic substrate 14 is bonded to the first main surface 13 a of the sintered body 13 through the resin layer 15. The second main surface 13b of the sintered body 13 is a surface facing the external substrate when the coil component 1 is mounted on the external substrate (not shown).

  The sintered body 13 includes a coil L configured by electrically connecting the conductors B1 to B10. The conductor B <b> 1 is provided on the upper portion of the sintered body 13 and is exposed on the first main surface 13 a of the sintered body 13. A lead-out part B1a is integrally formed at one end of the conductor B1, and the lead-out part B1a is exposed at one end face in the longitudinal direction of the sintered body 13 and is electrically connected to the terminal electrode 11. The conductor B10 is provided in the lower part of the sintered body 13, and the lead-out part B10a is integrally formed at one end thereof. The lead-out part B <b> 10 a is exposed at the other end surface in the longitudinal direction of the sintered body 13 and is electrically connected to the terminal electrode 12.

  The magnetic substrate 14 is made of a slurry made of ferrite (for example, Ni—Cu—Zn ferrite, Ni—Cu—Zn—Mg ferrite, Cu—Zn ferrite, or Ni—Cu ferrite) as a raw material by a doctor blade method. It is formed by coating on a film and drying the ferrite. The thickness of the magnetic substrate 14 is, for example, about 200 μm. The resin layer 15 interposed between the first main surface 13a of the sintered body 13 and the magnetic substrate 14 is formed of an epoxy resin.

  In the coil component 1 configured as described above, the conductor B1 is exposed on the first main surface 13a of the sintered body 13, and the magnetic substrate 14 is interposed between the resin layer 15 and the first main surface 13a of the sintered body 13. Therefore, the resin layer 15 forms a magnetic gap. And this resin layer 15 can relieve | moderate magnetic saturation, can suppress that magnetic saturation arises, and can improve a direct current | flow superimposition characteristic. Therefore, the coil component 1 configured as described above can improve the direct current superposition characteristics while having a simple structure.

  Hereinafter, a method for manufacturing the coil component 1 will be described with reference to FIGS. FIG. 3 is a diagram for explaining the stacking process. FIG. 4 is a diagram for explaining a method of manufacturing a coil component.

  First, the sintered compact 13 is produced in a sintered compact preparation process. The sintered body preparation process includes a stacking process for obtaining the stacked body 18 that is a precursor of the sintered body 13 and a firing process for firing the stacked body 18. Here, the lamination process of the laminated body 18 is demonstrated first. As shown in FIG. 3, the laminated body 18 is configured by alternately laminating 11 magnetic green sheets A1 to A11 and conductor patterns D1 to D10. The conductor patterns D1 to D10 are pastes of the conductors B1 to B10, respectively.

  The magnetic green sheets A1 to A11 are insulators having electrical insulation. The magnetic green sheets A1 to A11 are made of a slurry using ferrite (for example, Ni—Cu—Zn ferrite, Ni—Cu—Zn—Mg ferrite, Cu—Zn ferrite, or Ni—Cu ferrite) as a raw material. It is formed by applying on the film by the doctor blade method. The thickness of the magnetic green sheets A1 to A11 is, for example, about 60 μm.

  The conductor pattern D1 corresponds to approximately 5/8 turns of the coil L, and is formed in a substantially C shape on the magnetic green sheet A1. A lead-out pattern D1a is integrally formed at one end of the conductor pattern D1. The lead-out pattern D1a of the conductor pattern D1 is drawn out to the edge of the magnetic green sheet A1, and its end is exposed on the end face of the magnetic green sheet A1. For this reason, the lead-out portion pattern D1a is electrically connected to the terminal electrode 11. The other end of the conductor pattern D1 is electrically connected to a through-hole electrode C1 formed through the magnetic green sheet A1 in the thickness direction. For this reason, the conductor pattern D1 is electrically connected to one end of the corresponding conductor pattern D2 through the through-hole electrode C1 in a stacked state.

  The conductor patterns D2 to D9 correspond to approximately 3/4 turns of the coil L, and the conductor patterns D2, D4, D6, and D8 are approximately U on the magnetic green sheets A2, A4, A6, and A8, respectively. The conductor patterns D3, D5, D7, and D9 are formed in a substantially C shape on the magnetic green sheets A3, A5, A7, and A9. One end of each conductor pattern D2 to D9 includes a region electrically connected to each through-hole electrode C1 to C8 in a stacked state. The other ends of the conductor patterns D2 to D9 are electrically connected to the through-hole electrodes C2 to C9 formed through the magnetic green sheets A2 to A9 in the thickness direction, respectively. For this reason, each conductor pattern D2-D9 is each electrically connected with the end of each corresponding conductor pattern D3-D10 via each through-hole electrode C2-C9 in the laminated state.

  The conductor pattern D10 corresponds to approximately 7/8 turns of the coil L, and is formed in a substantially U shape on the magnetic green sheet A10. One end of the conductor pattern D10 includes a region electrically connected to each through-hole electrode C9 in a stacked state. A lead-out pattern D10a is integrally formed at the other end of the conductor pattern D10. The lead-out pattern D10a of the conductor pattern D10 is drawn out to the edge of the magnetic green sheet A10, and its end is exposed at the end face of the magnetic green sheet A10. For this reason, the lead-out portion pattern D10a is electrically connected to the terminal electrode 12.

  Each conductor pattern D1-D10 is formed by screen-printing the conductor paste which has silver or nickel as a main component.

When producing the magnetic green sheets A1 to A11 and the conductor patterns D1 to D10 having such a configuration, first, the magnetic green sheets A1 to A11 are prepared. At this time, the density of the magnetic green sheets A1 to A11 is adjusted to, for example, about 2.7 g / cm ³ by adding an acidic compound or deionization treatment. Next, through holes are formed by laser processing or the like at predetermined positions of the magnetic green sheets A1 to A9, that is, positions where the through hole electrodes C1 to C9 are to be formed. Next, the conductor patterns D1 to D10 are formed on the magnetic green sheets A1 to A10, respectively.

Next, the magnetic green sheets A1 to A11 are stacked in the order shown in FIG. 3, and pressure is applied in the stacking direction so that no gap is generated between the magnetic green sheets A1 to A11. At this time, the density of the magnetic green sheets A1 to A11 (about 2.7 g / cm ³ ) is lower than the density of the conventional magnetic green sheets (about 3.0 g / cm ³ ). In particular, the magnetic green sheet positioned between the conductor patterns D1 to D10 is greatly dented and deformed, and cracks and delamination (delamination) do not occur in the sintered body 13 after firing.

  As described above, the magnetic green sheets A1 to A11 are laminated, and the conductor patterns D1 to D10 are electrically connected to each other through the through-hole electrodes C1 to C9. A coil L having 5 turns is formed. Next, the pressure-bonded magnetic green sheets A1 to A11 are cut into chips to form individual laminates 18.

  In the firing step subsequent to the lamination step for obtaining the laminate 18, the laminate 18 is fired at a predetermined temperature (for example, about 870 ° C.) to form the sintered body 13. The sintered body 13 has, for example, a length in the longitudinal direction after firing of 3.2 mm, a width of 1.6 mm, and a height of 1.0 mm. The conductor B1 is exposed on the first main surface 13a of the sintered body 13.

  Next, terminal electrodes 11 and 12 are formed on the sintered body 13. The terminal electrodes 11 and 12 are baked at a predetermined temperature (for example, about 700 ° C.) after transferring an electrode paste mainly composed of silver, nickel, or copper to both side surfaces facing each other in the longitudinal direction of the sintered body 13. I do.

  In the magnetic substrate bonding step subsequent to the firing step, the sintered body 13 and the magnetic substrate 14 are bonded by an epoxy resin. Specifically, an epoxy resin is applied to the first main surface 13a where the conductor B1 of the sintered body 13 is exposed to form an epoxy resin layer. Next, a magnetic substrate 14 prepared in advance is bonded onto the epoxy resin layer. Next, heat is applied to the epoxy resin layer to cure the epoxy resin. As a method for curing the resin, natural standing may be used in addition to heating. The epoxy resin layer is cured by heat to form a resin layer 15, and the sintered body 13 and the magnetic substrate 14 are firmly bonded to each other by the resin layer 15. Next, barrel plating is performed on the surfaces of the terminal electrodes 11 and 12. Thereby, the coil component 1 is completed.

  In the present embodiment, in the magnetic substrate bonding step, a magnetic substrate 14 prepared in advance is used, and a method of bonding the magnetic substrate 14 and the sintered body 13 with an epoxy resin is used. However, the method is not limited to this method. . For example, the first resin layer is formed by applying an epoxy resin to the first main surface 13a where the conductor B1 of the sintered body 13 is exposed, and then a resin further containing magnetic powder on the first resin layer. A method may be used in which a second resin layer is formed by applying and a coil component is manufactured by curing the first resin layer and the second resin layer. Alternatively, the first resin layer is formed on the first main surface 13a where the conductor B1 of the sintered body 13 is exposed, the first resin layer is cured, and further includes magnetic powder on the cured first resin layer. A method of manufacturing a coil component by forming the second resin layer and curing the second resin layer may be used. Examples of magnetic powder include ferrite powder and ferromagnetic metal powder. In particular, the ferromagnetic metal powder is preferable because the saturation magnetic flux density is larger than that of the ferrite powder, and the DC superposition characteristics are maintained up to a high magnetic field.

  In the manufacturing method of the coil component 1 according to the present embodiment, the magnetic green sheets A1 to A11 and the conductor patterns D1 to D10 are alternately laminated and fired so that the conductor pattern D1 is exposed on the first main surface 13a. Then, the magnetic substrate 14 is bonded to the first main surface 13a of the sintered body 13 with the epoxy resin to form the coil component 1. The resin layer made of an epoxy resin forms a magnetic gap and can relieve magnetic saturation. For this reason, the coil component 1 which can improve a direct current | flow superimposition characteristic can be manufactured easily.

  The magnetic green sheets A1 to A11 are made of the same material and have the same thermal shrinkage rate. Therefore, when the laminated body 18 laminated from these magnetic green sheets is baked, the laminated body 18 shrinks. By using a material having a good balance and a different thermal shrinkage rate, it is possible to reliably suppress the occurrence of cracks and warpage in the sintered body. Further, since the magnetic green sheets A1 to A11 made of the same material are used for lamination, it is not necessary to newly provide a step of laminating different materials as compared with the case of using a conventional magnetic body and a non-magnetic body. Therefore, an increase in the number of manufacturing steps can be suppressed and cost reduction can be improved.

(Second Embodiment)
Hereinafter, the configuration of the coil component 2 according to the second embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a perspective view showing a coil component according to the second embodiment. FIG. 6 is a view for explaining a cross-sectional configuration of the coil component according to the second embodiment.

  The difference between the coil component 2 according to the second embodiment and the first embodiment is that magnetic gaps are formed on the first main surface 23a and the second main surface 23b of the sintered body 23, respectively. Other configurations are the same as the configuration of the coil component 1, and therefore, the same reference numerals are given and redundant description is omitted.

  The coil component 2 includes a sintered body 23 having a substantially rectangular parallelepiped shape, and a pair of terminal electrodes 21 and 22 formed on both end surfaces of the sintered body 23 in the longitudinal direction. The sintered body 23 has a first main surface 23a and a second main surface 23b facing each other. On the first main surface 23a side of the sintered body 23, the magnetic substrate 14 is bonded to the first main surface 23a via the resin layer 15, and on the second main surface 23b side of the sintered body 23, The magnetic substrate 16 is bonded to the second main surface 23b through the resin layer 17. The resin layer 15 and the resin layer 17 form magnetic gaps on the first main surface 23a and the second main surface 23b of the sintered body 23, respectively. The magnetic substrate 16 has the same configuration as the magnetic substrate 14, and the resin 17 has the same configuration as the resin layer 15.

  The sintered body 23 includes a coil L including conductors B1 to B10 and lead-out portions B1a and B10a. The conductor B1 is exposed on the first main surface 23a of the sintered body 23, and the conductor B10 is exposed on the second main surface 23b. The lead-out part B1a is exposed at one end face in the longitudinal direction of the sintered body 23 and is electrically connected to the terminal electrode 21. The lead-out part B <b> 10 a is exposed at the other end face in the longitudinal direction of the sintered body 23 and is electrically connected to the terminal electrode 22.

  The coil component 2 configured as described above can obtain the same effects as those of the first embodiment, and magnetic gaps are formed on the first main surface 23a and the second main surface 23b of the sintered body 23, respectively. Therefore, magnetic saturation can be further suppressed, and the DC superposition characteristics can be further improved.

  Next, with reference to FIG.7 and FIG.8, the manufacturing method of the coil component 2 which concerns on 2nd Embodiment is demonstrated. FIG. 7 is a diagram for explaining the stacking process. FIG. 8 is a diagram for explaining a method of manufacturing a coil component. The manufacturing method according to the present embodiment is substantially the same as that of the first embodiment, and the difference from the first embodiment will be mainly described.

  As shown in FIG. 7, the laminated body 19 which is a precursor of the sintered body 23 is configured by alternately laminating nine magnetic green sheets A1 to A9 and conductor patterns D1 to D10. Yes. The conductor patterns D1 to D9 are formed on the magnetic green sheets A1 to A9, respectively, as in the first embodiment, but the conductor pattern D10 is not formed on the magnetic green sheet but is formed alone.

  Therefore, in the sintered body preparation step, the conductor pattern D10 is formed by screen-printing a conductor paste mainly composed of silver or nickel on a sheet (not shown) different from the magnetic green sheet. Next, the sheet on which the conductor pattern D10 is printed and the magnetic green sheets A1 to A9 are laminated in the order shown in FIG. After the lamination, the sheet on which the conductor pattern D <b> 10 is printed is peeled off, and the laminated body 19 is cut into chips and fired to form a sintered body 23. Next, terminal electrodes 21 and 22 are formed on both end faces of the sintered body 23.

  In the magnetic substrate bonding step subsequent to the sintered body preparation step, the magnetic substrate 14 and the magnetic substrate 16 are bonded to the first main surface 23a and the second main surface 23b of the sintered body 23 with an epoxy resin, respectively. Is cured (see FIG. 8). Next, barrel plating is performed on the surfaces of the terminal electrodes 21 and 22. Thereby, the coil component 2 is completed. The manufacturing method according to the present embodiment can obtain the same effects as those of the first embodiment. Moreover, the method of producing a coil component by forming the 1st resin layer and the 2nd resin layer containing magnetic powder similarly to 1st Embodiment is applied to this embodiment.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the epoxy resin is used. However, the present invention is not limited to this, and silicone and other resins may be used.

It is a perspective view which shows the coil components which concern on 1st Embodiment. It is a figure for demonstrating the cross-sectional structure of the coil components which concern on 1st Embodiment. It is a figure for demonstrating a lamination process. It is a figure for demonstrating the manufacturing method of coil components. It is a perspective view which shows the coil components which concern on 2nd Embodiment. It is a figure for demonstrating the cross-sectional structure of the coil components which concern on 2nd Embodiment. It is a figure for demonstrating a lamination process. It is a figure for demonstrating the manufacturing method of coil components.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,2 ... Coil parts 11, 12, 21, 22 ... Terminal electrode, 13, 23 ... Sintered body, 13a, 23a ... 1st main surface, 13b, 23b ... 2nd main surface, 14, 16 ... Magnetic substrate (magnetic material), 15, 17 ... resin layer, 18, 19 ... laminated body, A1-A11 ... magnetic green sheet, B1-B10 ... conductor, D1-D10 ... conductor pattern, L ... coil.

Claims (5)

A sintered body comprising a plurality of conductors and a magnetic body , having first and second main surfaces facing each other, and provided with a coil configured by electrically connecting the plurality of conductors; ,
A resin layer formed on the first main surface;
Said first major surface, and a magnetic body disposed through the resin layer,
A coil component, wherein one of the plurality of conductors is exposed on the first main surface. The second main surface further includes a magnetic body disposed via a resin layer,
2. The coil component according to claim 1, wherein one of the plurality of conductors, which is different from the conductor exposed on the first main surface, is exposed on the second main surface. And a plurality of conductors and the magnetic body has a first and second main surfaces opposite to each other, the coil is provided formed by said plurality of conductors are electrically connected, wherein A sintered body preparation step of preparing a sintered body in which one of the plurality of conductors is exposed on the first main surface;
And a magnetic substrate bonding step of bonding the magnetic substrate to the first main surface with a resin. And a plurality of conductors and the magnetic body has a first and second main surfaces opposite to each other, the coil is provided formed by said plurality of conductors are electrically connected, wherein A sintered body preparation step of preparing a sintered body in which one of the plurality of conductors is exposed on the first main surface;
And a resin layer forming step of forming a second resin layer containing magnetic powder on the first resin layer after forming the first resin layer on the first main surface. Manufacturing method. The sintered body preparation step,
A laminating step of obtaining a laminate by alternately laminating a plurality of conductor patterns and a plurality of magnetic green sheets so that one conductor pattern of the plurality of conductor patterns is exposed;
The method for manufacturing a coil component according to claim 3, further comprising a step of firing the laminate.

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