JP2010147416A - Electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase an inductance value of an electronic component with two coils connected in parallel to each other. <P>SOLUTION: A laminated body 12 is formed by laminating magnetic material layers 16 and a magnetic material layer 17 having magnetic permeability higher than that of the magnetic material layer 16. Two external electrodes are arranged on side faces of the laminated body 12. Coils L1, L2 are incorporated in the laminated body 12, and connected in parallel to each other between the two external electrodes. The magnetic material layer 17 is arranged between the coil L1 and the coil L2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic component, and more particularly to an electronic component having a built-in coil.

  As a conventional electronic component, for example, a multilayer inductor described in Patent Document 1 is known. In the multilayer inductor, two coils are built in the multilayer body. The two coils are connected in parallel between two external electrodes provided on the surface of the laminate. Thereby, the resistance value of the multilayer inductor is reduced.

However, the multilayer inductor described in Patent Document 1 has a problem that the inductance value becomes small. More specifically, if the inductance values of the two coils are La and Lb and the combined inductance value is LA, the relationship 1 / LA = 1 / La + 1 / Lb is established. When this is solved for LA, LA = La · Lb / (La + Lb). Since Lb is smaller than La + Lb, LA is smaller than La. Similarly, since La is smaller than La + Lb, LA is smaller than Lb. That is, in the multilayer inductor described in Patent Document 1, the combined inductance value of the two coils is smaller than the inductance values La and Lb of the two coils.
JP-A-6-196334

  Accordingly, an object of the present invention is to increase the inductance value of an electronic component in which two coils are connected in parallel.

  According to an electronic component according to an aspect of the present invention, a laminate in which a first insulator layer and a second insulator layer having a higher magnetic permeability than the first insulator layer are laminated, The first external electrode and the second external electrode provided on the surface of the multilayer body, and the first external electrode and the second external electrode that are built in the multilayer body and parallel to each other between the first external electrode and the second external electrode. A first coil and a second coil connected to each other, and the second insulator layer is provided between the first coil and the second coil. It is characterized by.

  According to the present invention, the inductance value of an electronic component in which two coils are connected in parallel can be increased.

  Below, the electronic component which concerns on embodiment of this invention, and its manufacturing method are demonstrated.

(Configuration of electronic parts)
Hereinafter, an electronic component 10 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an electronic component 10 according to an embodiment. FIG. 2 is an exploded perspective view of the multilayer body 12 of the electronic component 10 according to the embodiment. Hereinafter, the stacking direction of the electronic component 10 is defined as the z-axis direction, the direction along the long side of the electronic component 10 is defined as the x-axis direction, and the direction along the short side of the electronic component 10 is defined as the y-axis direction. To do. The x axis, the y axis, and the z axis are orthogonal to each other.

  As shown in FIG. 1, the electronic component 10 includes a laminate 12 and external electrodes 14a and 14b. The laminated body 12 has a rectangular parallelepiped shape and incorporates coils L1 and L2. The external electrodes 14a and 14b are provided so as to cover the side surfaces (surfaces) located at both ends in the x-axis direction.

  As shown in FIG. 2, the multilayer body 12 is configured by laminating magnetic layers 16 a to 16 i, 17, 16 j to 16 r so that they are arranged in this order in the z-axis direction. In the following, when referring to the individual magnetic layers 16, alphabets are appended to the reference numerals, and when these are collectively referred to, the alphabets after the reference numerals are omitted.

  The magnetic layer 16 is a rectangular insulator layer made of ferromagnetic ferrite. In the present embodiment, the magnetic layer 16 is composed of Ni—Cu—Zn-based ferrite having a magnetic permeability of 10. The magnetic layer 17 is a rectangular insulator layer having a magnetic permeability higher than that of the magnetic layer 16 (130 to 1000. Therefore, the ferrite constituting the magnetic layer 17 is the ferrite constituting the magnetic layer 16. It is comprised by the Ni-Cu-Zn type ferrite which contains more Ni.

  As shown in FIG. 2, the coil L <b> 1 is a spiral coil that rotates and advances in the z-axis direction, and is provided on the positive side in the z-axis direction from the magnetic layer 17. As shown in FIG. 2, the coil L1 includes coil electrodes 18a to 18f and via hole conductors b1 to b5. In the following, when referring to the individual coil electrodes 18, alphabets are appended to the reference numerals, and when these are collectively referred to, the alphabets after the reference numerals are omitted.

  As shown in FIG. 2, each of the coil electrodes 18 a to 18 f is formed on the main surface of the magnetic layers 16 d to 16 i and is laminated together with the magnetic layer 16. Each coil electrode 18 is made of a conductive material made of Ag, has a length corresponding to 3/4 turns, and is arranged to overlap each other in the z-axis direction. The length of the coil electrode 18 is not limited to 3/4 turns.

  As shown in FIG. 2, each of the via-hole conductors b1 to b5 is formed so as to penetrate the magnetic layers 16d to 16h in the z-axis direction. The via-hole conductors b1 to b5 function as connecting portions that connect the ends of the adjacent coil electrodes 18 when the magnetic layers 16 and 17 are laminated. More specifically, the via-hole conductor b1 connects the end of the coil electrode 18a where the lead-out portion 20a is not provided and the end of the coil electrode 18b. The via hole conductor b2 connects the end of the coil electrode 18b to which the via hole conductor b1 is not connected and the end of the coil electrode 18c. The via-hole conductor b3 connects the end of the coil electrode 18c to which the via-hole conductor b2 is not connected and the end of the coil electrode 18d. The via-hole conductor b4 connects the end of the coil electrode 18d to which the via-hole conductor b3 is not connected and the end of the coil electrode 18e. The via-hole conductor b5 includes an end of the coil electrode 18e that is not connected to the via-hole conductor b4, and an end of the coil electrode 18f that is not provided with the lead-out portion 20b. Is connected.

  The coil electrodes 18a and 18f have lead portions 20a and 20b at their ends. The lead portions 20a and 20b are drawn to the negative and positive sides of the magnetic layers 16d and 16i in the x-axis direction, and are connected to the external electrodes 14a and 14b. Thereby, the coil L1 is connected to the external electrodes 14a and 14b.

  As shown in FIG. 2, the coil L <b> 2 is a spiral coil that advances in the z-axis direction while rotating, and is provided on the negative side in the z-axis direction from the magnetic layer 17. Furthermore, the coil L2 is provided so as to be aligned with the coil L1 in the z-axis direction. In the present embodiment, the coil axis of the coil L1 coincides with the coil axis of the coil L2. The coil L2 has the same structure as the coil L1. Here, the same structure means a structure in which the DC superposition characteristics of the coil L1 and the coil L2 are the same, for example, means that the number of turns and the wiring structure of the coil L1 and the coil L2 are the same.

  As shown in FIG. 2, the coil L2 includes coil electrodes 18g to 18l and via-hole conductors b6 to b10. In the following, when referring to the individual coil electrodes 18, alphabets are appended to the reference numerals, and when these are collectively referred to, the alphabets after the reference numerals are omitted.

  As shown in FIG. 2, the coil electrodes 18 g to 18 l are formed on the main surfaces of the magnetic layers 16 j to 16 o and laminated together with the magnetic layer 16. Each coil electrode 18 is made of a conductive material made of Ag, has a length corresponding to 3/4 turns, and is arranged to overlap each other in the z-axis direction. The length of the coil electrode 18 is not limited to 3/4 turns.

  As shown in FIG. 2, the via-hole conductors b6 to b10 are formed so as to penetrate the magnetic layers 16j to 16n in the z-axis direction. The via-hole conductors b6 to b10 function as connecting portions that connect the ends of the adjacent coil electrodes 18 when the magnetic layers 16 and 17 are laminated. More specifically, the via-hole conductor b6 connects the end of the coil electrode 18g where the lead-out portion 20c is not provided and the end of the coil electrode 18h. The via hole conductor b7 connects the end of the coil electrode 18h to which the via hole conductor b6 is not connected and the end of the coil electrode 18i. The via-hole conductor b8 connects the end of the coil electrode 18i that is not connected to the via-hole conductor b7 and the end of the coil electrode 18j. The via-hole conductor b9 connects the end of the coil electrode 18j to which the via-hole conductor b8 is not connected and the end of the coil electrode 18k. The via-hole conductor b10 includes an end of the coil electrode 18k that is not connected to the via-hole conductor b9, and an end of the coil electrode 18l that is not provided with the lead-out portion 20d. Is connected.

  Further, the coil electrodes 18g and 18l have lead portions 20c and 20d at their ends. The lead portions 20c and 20d are drawn to the negative side and the positive side of the magnetic layers 16j and 16o, respectively, and are connected to the external electrodes 14a and 14b. Thereby, the coil L1 and the coil L2 are mutually connected in parallel between the external electrode 14a and the external electrode 14b.

(effect)
According to the electronic component 10, a relatively large inductance value can be obtained even when two coils are connected in parallel. More specifically, in the multilayer inductor described in Patent Document 1, since two coils are connected in parallel, the combined inductance value of the two coils is smaller than the inductance value of the two coils alone. .

  On the other hand, in the electronic component 10, a magnetic layer 17 having a higher magnetic permeability than the magnetic layer 16 is provided between the coil L1 and the coil L2. Therefore, the magnetic flux generated by the coils L1 and L2 passes through the magnetic layer 17. As a result, compared with the multilayer inductor described in Patent Document 1, the magnetic flux density in the multilayer body 12 is increased, and the inductance values of the coils L1 and L2 are increased.

  The inventor of the present application performed a computer simulation described below in order to make the effect of the electronic component 10 clearer. Specifically, the magnetic permeability of the magnetic layer 16 was set to 10, the magnetic permeability of the magnetic layer 17 was changed between 10 and 400, and the change rate of the combined inductance value of the coil L1 and the coil L2 was calculated. The reference for the rate of change of the combined inductance value is the combined inductance value when the magnetic permeability of the magnetic layer 17 is 10. This corresponds to the multilayer inductor described in Patent Document 1.

  FIG. 3 is a graph showing the results of this computer simulation. The vertical axis represents the change rate of the inductance value, and the horizontal axis represents the magnetic permeability. According to FIG. 3, it can be understood that if the magnetic permeability of the magnetic layer 17 is increased, the combined inductance value is increased. Therefore, it can be seen that the composite inductance value of the electronic component 10 can be increased by making the magnetic layer 17 have a higher magnetic permeability than the magnetic layer 16.

  In particular, when the magnetic permeability of the magnetic layer 17 is 200 or more, the combined inductance value is converged. Therefore, when the magnetic layer 16 has a magnetic permeability of 10, the magnetic layer 17 preferably has a magnetic permeability of 200 or more. In other words, the magnetic permeability of the magnetic layer 17 is desirably 20 times or more that of the magnetic layer 16.

  In addition, as described below, the electronic component 10 has a one-step staircase DC superposition characteristic. FIG. 4 is a graph showing the DC superposition characteristics of the electronic component 10. The vertical axis represents the inductance value, and the horizontal axis represents the direct current.

  More specifically, when the direct current flowing through the coils L1 and L2 increases, magnetic saturation occurs in the laminated body 12, and the inductance value rapidly decreases. Here, if the structures of the coil L1 and the coil L2 are different, the magnitude of the direct current at which the inductance value of the coil L1 rapidly decreases is different from the magnitude of the direct current at which the inductance value of the coil L2 rapidly decreases. End up. Therefore, when the structures of the coil L1 and the coil L2 are different, as shown by the dotted line in FIG. 4, the electronic component has a DC superposition characteristic in which the inductance value decreases in multiple stages.

  On the other hand, in the electronic component 10, the structure of the coil L1 and the coil L2 is equal. Therefore, the magnitude of the direct current at which the inductance value of the coil L1 rapidly decreases is equal to the magnitude of the direct current at which the inductance value of the coil L2 rapidly decreases. Therefore, when the structures of the coil L1 and the coil L2 are the same, as shown by the solid line in FIG. 4, the electronic component 10 has a one-step staircase DC superposition characteristic.

  In the electronic component 10, all the coil electrodes 18 are provided on the magnetic layer 16 and are not provided on the magnetic layer 17. Therefore, it is not necessary to form the coil electrode 18 on each of the magnetic layers 16 and 17 made of different materials. Therefore, when forming the coil electrode 18, it is not necessary to perform screen printing under conditions suitable for the magnetic layer 16 and the magnetic layer 17. As a result, the manufacturing cost of the electronic component 10 can be reduced.

(Method for manufacturing electronic parts)
Below, the manufacturing method of the electronic component 10 is demonstrated, referring FIG.1 and FIG.2.

A ceramic green sheet to be the magnetic layer 16 is produced by the following process. Ferric oxide (Fe ₂ O ₃ ), zinc oxide (ZnO), nickel oxide (NiO), and copper oxide (CuO) are weighed at a predetermined ratio, and each material is put into a ball mill as a raw material. Mix. The obtained mixture is dried and pulverized, and the obtained powder is calcined at 750 ° C. for 1 hour. The obtained calcined powder is wet pulverized by a ball mill, dried and crushed to obtain a ferromagnetic first ferrite ceramic powder.

To this first ferrite ceramic powder, add cobalt oxide (Co ₃ O ₄ ), binder (vinyl acetate, water-soluble acrylic, etc.), plasticizer, wetting agent, and dispersing agent, and then mix with a ball mill. Defoaming is performed under reduced pressure. The obtained ceramic slurry is formed into a sheet by the doctor blade method and dried to produce a ceramic green sheet to be the magnetic layer 16.

Next, a ceramic green sheet to be the magnetic layer 17 is produced by the following process. Ferric oxide (Fe ₂ O ₃ ), zinc oxide (ZnO), nickel oxide (NiO), and copper oxide (CuO) are weighed at a predetermined ratio, and each material is put into a ball mill as a raw material. Mix. At this time, each material is prepared so that the proportion of nickel oxide (NiO) is higher than that of the first ferrite ceramic. The obtained mixture is dried and pulverized, and the obtained powder is calcined at 750 ° C. for 1 hour. The obtained calcined powder is wet pulverized by a ball mill, dried and crushed to obtain a ferromagnetic second ferrite ceramic powder.

To this second ferrite ceramic powder, add cobalt oxide (Co ₃ O ₄ ), binder (vinyl acetate, water-soluble acrylic, etc.), plasticizer, wetting agent, and dispersing agent, and then mix with a ball mill. Defoaming is performed under reduced pressure. The obtained ceramic slurry is formed into a sheet by a doctor blade method and dried to produce a ceramic green sheet to be the magnetic layer 17.

  Next, the via-hole conductors b1 to b10 are formed on the ceramic green sheets to be the magnetic layers 16d to 16h and 16j to 16n, respectively. Specifically, as shown in FIG. 2, a via hole is formed by irradiating a ceramic green sheet to be the magnetic layers 16 d to 16 h and 16 j to 16 n with a laser beam. Next, the via hole is filled with a conductive paste such as Ag, Pd, Cu, Au or an alloy thereof by a method such as printing.

  Next, a conductive paste mainly composed of Ag, Pd, Cu, Au, or an alloy thereof is applied on the ceramic green sheets to be the magnetic layers 16d to 16o by a method such as a screen printing method or a photolithography method. Thus, the coil electrodes 18a to 18l are formed. Note that the via-hole conductor may be filled with a conductive paste simultaneously with the formation of the coil electrodes 18a to 18l.

  Next, as shown in FIG. 2, these ceramic green sheets are laminated so that the magnetic layers 16a to 16i, 17, 16j to 16r are arranged in this order from the positive side in the z-axis direction. More specifically, a ceramic green sheet to be the magnetic layer 16r is disposed. Next, the ceramic green sheet to be the magnetic layer 16q is placed and temporarily pressed onto the ceramic green sheet to be the magnetic layer 16r. Thereafter, the ceramic green sheets to be the magnetic layers 16p, 16o, 16n, 16m, 16l, 16k, 16j, 17, 16i, 16h, 16g, 16f, 16e, 16d, 16c, 16b, and 16a are similarly arranged in this order. Is laminated and temporarily press-bonded to obtain a mother laminate. Further, the mother laminate is subjected to main pressure bonding by a hydrostatic pressure press or the like.

  Next, the mother laminated body is cut into a laminated body 12 having a predetermined size by pressing to obtain an unfired laminated body 12. The unfired laminate 12 is subjected to binder removal processing and firing. The binder removal treatment is performed, for example, in a low oxygen atmosphere at 260 ° C. for 3 hours. Firing is performed, for example, at 900 ° C. for 2.5 hours.

  The fired laminated body 12 is obtained through the above steps. The laminated body 12 is chamfered by barrel processing. Thereafter, a silver electrode to be the external electrodes 14a and 14b is formed on the surface of the laminate 12 by applying and baking an electrode paste whose main component is silver by a method such as an immersion method. The silver electrode is dried at 120 ° C. for 15 minutes, and the silver electrode is baked at 700 ° C. for 60 minutes. Finally, the external electrodes 14a and 14b are formed by performing Ni plating / Sn plating on the surface of the silver electrode. Through the above steps, the electronic component 10 as shown in FIG. 1 is completed.

1 is an external perspective view of an electronic component according to an embodiment of the present invention. It is a disassembled perspective view of the laminated body of the electronic component of FIG. It is the graph which showed the result of computer simulation. It is the graph which showed the direct current superposition characteristic of electronic parts.

Explanation of symbols

L1, L2 Coil b1 to b10 Via-hole conductor 10 Electronic component 12 Laminated body 14a, 14b External electrode 16a-16r, 17 Magnetic body layer 18a-18l Coil electrode 20a-20d Lead-out part

Claims (3)

A laminate in which a first insulator layer and a second insulator layer having a higher magnetic permeability than the first insulator layer are laminated;
A first external electrode and a second external electrode provided on the surface of the laminate;
A first coil and a second coil that are built in the laminate and connected in parallel between the first external electrode and the second external electrode;
With
The second insulator layer is provided between the first coil and the second coil;
Electronic parts characterized by The first coil and the second coil are arranged in a stacking direction;
The electronic component according to claim 1. The first coil and the second coil have the same structure;
The electronic component according to claim 1, wherein:

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