JPWO2011058945A1 - Multilayer ceramic electronic components - Google Patents

Abstract

Provided is a multilayer ceramic electronic component capable of reducing noise generated in a via electrode in a base material layer. The multilayer ceramic electronic component according to the present invention includes a base material layer 2, a coil pattern 9 that is disposed inside the base material layer 2 and generates a magnetic field in the base material layer 2, and at least a part of the base material layer 2. A portion of the via electrode 8 that is in contact with the base material layer 2 around the via electrode 8 is covered with a low magnetic layer 14 having a magnetic permeability lower than that of the base material layer 2. It is characterized by that.

Description

  The present invention relates to a multilayer ceramic electronic component. In particular, the present invention relates to a multilayer ceramic electronic component having a coil pattern inside a base material layer.

  Ferrite ceramic is often used for multilayer ceramic electronic components having an inductor function. In recent years, with the demand for miniaturization, ferrite ceramics with high magnetic permeability are used.

  For example, Patent Document 1 discloses a multilayer ceramic electronic component as shown in FIG. This multilayer ceramic electronic component includes a base material layer 102 and surface layers 103 and 104 disposed on the main surface of the base material layer 102. A coil pattern 109 is disposed inside the base material layer 102. The coil pattern 109 is electrically connected to the external electrode 107 through the internal electrode 106 and the via electrode 108. On the main surface of the multilayer ceramic electronic component, the mounting components 110 and 111 are fixed with solder bumps 112 and solder 113.

WO2007 / 148556

  In Patent Document 1, a high-frequency signal flows through the coil pattern 109. In that case, a magnetic field is generated in the base material layer 102 by the coil pattern 109. Due to the change in the magnetic field, an electromotive force is generated in the via electrode in the base material layer 102 due to electromagnetic induction, and noise is generated.

  This invention is made | formed in view of this subject, and it aims at reducing the noise which generate | occur | produces in the via electrode in a base material layer.

  The multilayer ceramic electronic component according to the present invention includes a base material layer, a coil pattern which is disposed inside the base material layer and generates a magnetic field in the base material layer, and at least a part thereof is inside the base material layer. And at least a part of a portion in contact with the base material layer around the via electrode is a low magnetic layer having a magnetic permeability lower than the magnetic permeability of the base material layer. It is characterized by being covered.

  According to the structure of this invention, the noise which generate | occur | produces in the via electrode in the base material layer resulting from a magnetic field change can be reduced.

  In the multilayer ceramic electronic component according to the present invention, the base material layer is preferably made of a ferrite ceramic.

  In such a case, the coil pattern can be reduced in size.

  In the multilayer ceramic electronic component according to the present invention, the low magnetic layer preferably has a magnetic permeability of 1 to 30.

  In such a case, changes in the magnetic field of the via electrode can be effectively suppressed.

  In the multilayer ceramic electronic component according to the present invention, it is preferable that the multilayer body further has a surface layer disposed on at least one main surface of the base material layer.

  In such a case, the magnetic field change of the internal electrode disposed in the vicinity of the main surface of the laminate can be suppressed.

  Moreover, in the multilayer ceramic electronic component according to the present invention, the multilayer ceramic electronic component includes an internal electrode disposed inside the base material layer and an external electrode disposed on the main surface of the multilayer body, and the via electrode is the internal electrode. And the external electrode are preferably electrically connected.

  In such a case, the magnetic field change of the via electrode connecting the internal electrode and the external electrode can be suppressed.

  In the multilayer ceramic electronic component according to the present invention, it is preferable that the multilayer ceramic electronic component includes an external electrode disposed on the main surface of the multilayer body, and the via electrode is formed so as to be electrically connected to the coil pattern. .

  In such a case, the magnetic field change of the via electrode connected to the coil pattern can be suppressed.

  In the multilayer ceramic electronic component according to the present invention, it is preferable that the via electrode is formed so as to penetrate the base material layer perpendicularly to the main surface of the base material layer.

  In this case, the magnetic field change of the via electrode penetrating the base material layer can be suppressed.

  According to the configuration of the present invention, the magnetic field change in the via electrode can be suppressed by the low magnetic layer around the via electrode. Therefore, noise generated in the via electrode in the base material layer due to the magnetic field change can be reduced.

It is sectional drawing which shows the laminated ceramic electronic component which concerns on this invention. It is a schematic diagram which shows shielding of the magnetic field in this invention. It is sectional drawing which shows the manufacturing method of the multilayer ceramic electronic component which concerns on this invention. It is sectional drawing which shows the conventional multilayer ceramic electronic component.

  Hereinafter, modes for carrying out the present invention will be described.

  FIG. 1 is a cross-sectional view showing a multilayer ceramic electronic component of the present invention.

  This multilayer ceramic electronic component constitutes a DC-DC converter, for example. The multilayer ceramic electronic component includes a multilayer body 5 having a base material layer 2, surface layers 3 and 4, internal electrodes 6 c and 6 d, via electrodes 8 a, 8 b, 8 c, 8 d and 8 e, and a coil pattern 9. I have. External electrodes 7 a, 7 b, 7 c, 7 d, and 7 e are disposed on the main surface of the stacked body 5.

  The surface layers 3 and 4 are disposed on the main surface of the base material layer 2. The surface layers 3 and 4 serve to prevent the internal electrode 6d and the via electrodes 8a, 8b, 8c, 8d, and 8e in the surface layers 3 and 4 from being affected by the magnetic field of the coil pattern 9.

  Mounted components 10 and 11 are mounted on the main surface of the surface layer 3. The mounting component 10 is an IC chip, for example, and is electrically connected to the external electrode 7e disposed on the main surface of the surface layer 3 via the solder bumps 12. The electronic component 11 is, for example, a chip capacitor, and is electrically connected to the external electrode 7 d disposed on the main surface of the surface layer 3 via the solder 13. The external electrodes 7a, 7b, 7c arranged on the main surface of the surface layer 4 are used as terminal electrodes when a multilayer ceramic electronic component is mounted on a circuit board, for example.

  The coil pattern 9 is disposed inside the base material layer 2 and generates a magnetic field in the base material layer 2.

  The via electrodes 8a, 8b, 8c, 8d, 8e are arranged perpendicular to the main surface of the multilayer ceramic electronic component. The via electrodes 8a, 8b, 8c, 8d, and 8e are disposed inside the base material layer 2 and the surface layers 3 and 4. The present invention can be applied to the via electrodes 8a, 8b, 8c, and 8d at least partially disposed inside the base material layer 2 as described below. For example, the via electrode 8 a is formed so as to penetrate the base material layer 2 perpendicular to the main surface of the base material layer 2. The via electrode 8b is formed so as to electrically connect the coil pattern 9 and the external electrode 7b. The via electrode 8c is formed so as to electrically connect the internal electrode 6c and the external electrode 7c. The via electrode 8d is formed so as to electrically connect the coil pattern 9 and the internal electrode 6d.

  In the present invention, the low magnetic layers 14a, 14b, 14c having a permeability lower than the permeability of the base material layer 2 is at least part of the portions in contact with the base material layer 2 around the via electrodes 8a, 8b, 8c, 8d. , 14d, respectively. The low magnetic layers 14a, 14b, 14c, and 14d may cover at least part of the periphery of the via electrodes 8a, 8b, 8c, and 8d. Further, when the entire surface around the via electrodes 8a, 8b, 8c, and 8d is covered, the magnetic field shielding effect becomes more remarkable.

  The diameter of the via electrodes 8a, 8b, 8c, 8d is preferably 100 μm to 400 μm. When the via electrodes 8a, 8b, 8c and 8d and the low magnetic layers 14a, 14b, 14c and 14d are concentric, the low magnetic layers 14a, 14b, 14c and 14d are formed from the outer periphery of the via electrodes 8a, 8b, 8c and 8d. It is preferable that the distance to the outer periphery, that is, the width of the ring of the low magnetic layers 14a, 14b, 14c, and 14d is 40 to 100 μm. Moreover, it is preferable that the base material layer 2 is comprised with a ferrite ceramic.

  The surface layers 3 and 4 and the low magnetic layers 14a, 14b, 14c and 14d are preferably ferrite ceramics having the same composition. In such a case, since a common material can be used, the manufacturing cost can be reduced. “The same composition” includes the same type and ratio of the main component elements but different types of additives. Moreover, it is preferable that the base material layer 2, the surface layers 3 and 4, and the low magnetic layers 14a, 14b, 14c, and 14d are ferrite ceramics having the same composition system. In such a case, the strength of the fired laminate is improved. The “same composition system” includes those having the same type of main component elements but having a slightly different ratio.

Moreover, it is preferable that the magnetic permeability of the base material layer 2 is 70 to 300 at 1 MHz. The magnetic permeability of the surface layers 3 and 4 and the low magnetic layers 14a, 14b, 14c and 14d is preferably 1 to 30 at 1 MHz. The ferrite ceramic is preferably spinel type ferrite (MFeO ₄ : M is a divalent metal ion) or garnet type ferrite (R ₃ Fe ₅ O ₁₂ : R is a trivalent metal ion).

In the present embodiment, the base material layer 2 is made of, for example, an Fe—Ni—Zn—Cu ferrite ceramic. In this case, if a mixture of ferric oxide (Fe ₂ O ₃ ), zinc oxide (ZnO), and nickel oxide (NiO) is used at a predetermined ratio, the base material has a permeability of 300 at 1 MHz. A layer can be obtained.

The surface layers 3 and 4 and the low magnetic layers 14a, 14b, 14c, and 14d are made of, for example, an Fe—Zn—Cu ferrite ceramic. In this case, if a mixture of ferric oxide (Fe ₂ O ₃ ) and zinc oxide (ZnO) at a predetermined ratio different from the above is used, the low magnetic property having a magnetic permeability of 1.0 at 1 MHz. A layer or a surface layer can be obtained.

  In the above-described example, the Fe—Ni—Zn—Cu based ferrite ceramic is used, but an Fe—Mn—Zn based or Fe—Ni—Zn based ferrite ceramic may be used. All of these crystal structures have a spinel crystal structure. A ferrite ceramic having another crystal structure such as a garnet type may be used.

As spinel type ferrite (MFe ₂ O ₄ : M is a divalent metal ion), for example, nickel zinc ferrite: (Ni _1-X Zn _X ) Fe ₂ O ₄ , manganese zinc ferrite (Mn _1-X Zn _X ) Fe ₂ O ₄ , nickel ferrite: NiFe ₂ O ₄ , manganese ferrite: MnFe ₂ O ₄ , zinc ferrite: ZnFe ₂ O ₄ , copper ferrite: CuFe ₂ O ₄ , cobalt ferrite: CoFe ₂ O ₄ , magnesium ferrite: MgFe ₂ O ₄ , lithium ferrite: (Li _0.5 Fe _0.5 ) Fe ₂ O ₄ , gamma iron oxide (γ-Fe ₂ O ₃ ): Fe _2/3 □ _1/3 Fe ₂ O ₄ (“□” is a vacancy And magnetite (iron ferrite): Fe ₃ O _{4 and the} like.

Examples of garnet-type ferrite (R ₃ Fe ₅ O ₁₂ : R is a trivalent metal ion) include, for example, YIG (yttrium iron garnet): Y ₃ Fe ₅ O ₁₂ , CVG (calcium vanadium iron garnet): Ca ₃ Fe _3.5 V _1.5 O ₁₂ , gadolinium iron garnet: Gd ₃ Fe ₅ O _{12 and the} like.

  FIG. 2 is a schematic diagram showing how the magnetic field is shielded. FIG. 2 is a view of the via electrode 8, the low magnetic layer 14, the magnetic field source 15, and the lines of magnetic force 16 disposed in the base material layer as viewed from above the multilayer ceramic electronic component. A low magnetic layer 14 is disposed around the via electrode 8. For the sake of understanding, a magnetic field source 15 that generates a magnetic field is assumed. As the magnetic field source 15, the coil pattern of FIG. 1 is assumed. Magnetic field lines 16 are generated around the magnetic field source 15.

  In this case, the low magnetic layer 14 having a low magnetic permeability is less likely to be polarized than the base layer having a high magnetic permeability, and the magnetic field lines 16 are difficult to pass through. For this reason, the magnetic force lines 16 are less likely to enter the low magnetic layer 14. Therefore, it is difficult for magnetic lines of force to enter the via electrode 8, and a change in the magnetic field in the via electrode 8 can be suppressed.

  In the present invention, as the magnetic field source, not only the coil pattern but also the via electrode can be a magnetic field source. That is, when a current flows through the via electrode, a magnetic field is generated around the via electrode by the current. The magnetic field may affect other via electrodes and generate noise. The present invention is also effective against a magnetic field caused by such a via electrode.

  Next, a method for manufacturing a multilayer ceramic electronic component will be described.

  The low magnetic layer around the via electrode, which is a configuration of the present invention, is produced as shown in FIG. First, as shown in FIG. 3A, a specific ceramic green sheet 21 is prepared. This ceramic green sheet is obtained by adding a binder, a plasticizer, a wetting agent, a dispersing agent, etc. to the prepared ferrite raw material powder to form a slurry, which is then formed into a sheet shape. And the through-hole 22 is formed in the ceramic green sheet 21, as shown in FIG.3 (B). The through hole 22 can be formed by a laser or the like. Next, as shown in FIG. 3C, the low magnetic layer 14 is formed in the through hole 22. For example, the low magnetic layer 14 is made into a paste by adding a binder, a plasticizer, or the like to the prepared ferrite raw material powder and filling the through holes 22. Then, as shown in FIG. 3D, the through hole 22 is formed again in the low magnetic layer 14. Then, as shown in FIG. 3E, the via electrode 8 is formed by filling the through hole 22 with a conductive paste. The positional relationship between the low magnetic layer 14 and the via electrode 8 can be adjusted by adjusting the size and position of the through hole 22. For example, the positional relationship may be such that the low magnetic layer 14 covers a part of the periphery of the via electrode 8.

  In addition, an internal electrode, an external electrode, and an electrode pattern to be a coil pattern are formed on a specific ceramic green sheet. The electrode pattern can be formed, for example, by printing a conductive paste.

  And in order to form each of the base material layer 2 and the surface layers 3 and 4, a predetermined number of ceramic green sheets are laminated in a predetermined number and fired after pressure bonding. Next, the external electrode is plated. For example, a nickel plating film and a gold plating film are sequentially formed by electroless plating. Then, a mounting component is mounted on the external electrode.

  The via electrode can be formed not only in a circular cross section but also in an elliptical shape, a square shape, and a rectangular shape. For example, in FIG. 3, the cross-sectional shape of the low magnetic layer 14 may be a square, and the cross-sectional shape of the via electrode 8 may be a circle.

  Further, in order to simultaneously manufacture a plurality of multilayer ceramic electronic components, a plurality of multilayer ceramic electronic components may be formed in a collective state. In that case, dividing grooves are formed before firing. And it can divide | segment along a division | segmentation groove | channel after baking, and can take out each multilayer ceramic electronic component. Moreover, you may divide | segment before baking. In this case, the firing step is performed in the state of individual multilayer ceramic electronic components. For the plating step, for example, electrolytic plating using a barrel can be used. Alternatively, a plurality of multilayer ceramic electronic components may be formed in an aggregated state, and may be divided by forming divided grooves after firing.

  In the above, the manufacturing method of the multilayer ceramic electronic component was demonstrated. The multilayer ceramic electronic component of the present invention is not limited to this content, and can be appropriately changed within a range not impairing the gist of the invention.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Base material layer 3, 4 Surface layer 5 Laminated body 6c, 6d Internal electrode 7a, 7b, 7c, 7d, 7e Surface electrode 8, 8a, 8b, 8c, 8d, 8e Via electrode 9 Coil pattern 10, 11 Mounting Component 12 Solder bump 13 Solder 14, 14a, 14b, 14c, 14d Low magnetic layer 15 Magnetic field source 16 Magnetic field line 21 Ceramic green sheet 22 Through hole 102 Base layer 103, 104 Surface layer 106 Internal electrode 107 Surface electrode 108 Via electrode 109 Coil Pattern 110, 111 Mounting component 112 Solder bump 113 Solder

Claims (7)

A laminate having a base material layer, a coil pattern that is arranged inside the base material layer and generates a magnetic field in the base material layer, and a via electrode that is at least partially arranged inside the base material layer Equipped with a body,
A multilayer ceramic electronic component, wherein at least part of a portion in contact with the base material layer around the via electrode is covered with a low magnetic layer having a magnetic permeability lower than that of the base material layer.   The multilayer ceramic electronic component according to claim 1, wherein the base material layer is made of a ferrite ceramic.   The multilayer ceramic electronic component according to claim 1 or 2, wherein the magnetic permeability of the low magnetic layer is 1 to 30.   The multilayer ceramic electronic component according to any one of claims 1 to 3, wherein the multilayer body further includes a surface layer disposed on at least one main surface of the base material layer.   An internal electrode disposed inside the base material layer; and an external electrode disposed on a main surface of the laminate, wherein the via electrode electrically connects the internal electrode and the external electrode. The multilayer ceramic electronic component of any one of Claims 1-4 currently formed in.   The external electrode arrange | positioned on the main surface of the said laminated body is provided, The said via electrode is formed so that the said coil pattern and the said external electrode may be electrically connected. The multilayer ceramic electronic component according to Item.   The multilayer ceramic electronic component according to claim 1, wherein the via electrode is formed so as to penetrate the base material layer perpendicularly to a main surface of the base material layer.

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