JP2005340375A - Ceramic electronic component and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic electronic component which can have desired material characteristics at respective parts of a ceramic substrate without burning different ceramic materials at the same time, and to provide a manufacturing method thereof. <P>SOLUTION: The electronic component has the ceramic substrate having 1st and 2nd ceramic elements formed in one body. The 1st ceramic element has a 1st hole and a 1st filling material is charged in at least a portion of the 1st hole; and the 2nd ceramic element portion has a 2nd hole and a 2nd filling material is charged in at least a portion of the 2nd hole, and the 1st hole and 2nd hole are different in diameter mean value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ceramic electronic component such as a laminated LC filter and a method for manufacturing the same.

As a ceramic electronic component in which a coil and a capacitor are arranged inside a ceramic substrate, there is one described in Patent Document 1. Patent Document 1 describes a T-type multilayer LC filter in which a coil and a capacitor are arranged inside one ceramic substrate.
JP-A-10-190391

  In the multilayer LC filter having such a configuration, there is a problem that it is difficult to obtain a large capacity in the capacitor portion when the dielectric constant of the ceramic material constituting the ceramic substrate is low. On the other hand, when a ceramic material having a high dielectric constant is used, there is a problem that a large stray capacitance is generated for the coil and the self-resonant frequency is lowered.

  That is, it is difficult to simultaneously increase the capacitance of the capacitor and the self-resonance frequency of the coil, which has been a factor that hinders improvement of noise attenuation characteristics.

  In order to solve this problem, the ceramic material constituting the ceramic base is changed between the coil portion and the capacitor portion. However, when different ceramic materials are fired at the same time, the shrinkage rates of the respective materials are different, and thus there is a problem that cracks are likely to occur in the ceramic substrate, which makes manufacturing difficult.

  Accordingly, an object of the present invention is to provide a ceramic electronic component that can obtain desired material characteristics in each part of a ceramic substrate without simultaneously firing different ceramic materials, and a method for manufacturing the same.

  In order to solve the above problems, a ceramic electronic component according to the present invention is an electronic component having a ceramic base body in which a first ceramic element portion and a second ceramic element portion are integrally formed, and the first ceramic element portion. Has a first hole, at least a portion of the first hole is filled with a first filling material, and the second ceramic element portion has a second hole. And at least a part of the second hole is filled with the second filling material, and the first hole and the second hole have different average diameters. It is characterized by.

  More specifically, a coil conductor is incorporated in the first ceramic element portion, and a capacitor conductor is incorporated in the second ceramic element portion.

  By filling the pores of the first ceramic element portion and the second ceramic element portion with different filling materials, characteristics such as dielectric constant and magnetic permeability can be made different, and different materials are not fired simultaneously. However, different characteristics can be obtained in each part of the ceramic substrate. Specifically, the effective dielectric constant can be decreased in the first ceramic element portion in which the coil conductor is incorporated, and the effective dielectric constant can be increased in the second ceramic element portion in which the capacitor conductor is incorporated. .

  In the ceramic electronic component according to the present invention, the ceramic base is made of a magnetic material, the first filling material has a smaller dielectric constant than the magnetic material, and the second filling material is the magnetic material. It is preferable to have a dielectric constant greater than that of the body material.

  Usually, the relative dielectric constant of the magnetic material is about 15. However, by using a material having a smaller dielectric constant as the first filling material, the effective dielectric constant of the first ceramic element portion can be lowered. . Further, by using a material having a larger dielectric constant as the second filling material, the effective dielectric constant of the second ceramic element portion can be increased.

  The method for manufacturing a ceramic electronic component according to the present invention includes a first ceramic element portion having a first hole and a second ceramic element portion having a second hole having a smaller diameter than the first hole. For preparing a ceramic substrate integrally formed, a first filling step for filling the first hole with a first filling material, and a second filling for the second hole. And a second filling step of filling the filling material, wherein the second filling material is filled by reducing the pressure to a pressure lower than that of the first filling step. And

  Since the pressure is not reduced so much in the first filling step, the first filling material is not easily filled into the second hole having a small diameter, and is selectively filled into the first hole having a large diameter. Then, by reducing the pressure to a pressure lower than that in the first filling step and filling the second filling material, the second filling material is filled into the second holes having a small diameter. At this time, since the first hole is already filled with the first filling material by the previous first filling step, the first hole is hardly filled with the second filling material. .

  By manufacturing in this way, it becomes possible to selectively fill the first hole and the second hole with different filling materials.

  By filling the pores of the first ceramic element portion and the second ceramic element portion with different filling materials, characteristics such as dielectric constant and magnetic permeability can be made different, and different materials are not fired simultaneously. However, different characteristics can be obtained in each part of the ceramic substrate.

  Further, in the ceramic base preparation step, a first ceramic green sheet is produced using a ceramic slurry containing a ceramic raw material powder and a spherical first burned material, and the ceramic raw material powder and the spherical first powder A first ceramic green sheet is produced by using a ceramic slurry containing a second burned material having an average diameter smaller than that of the burned material, and a plurality of the first ceramic green sheets are laminated. A laminated body in which a sheet laminated portion and a second green sheet laminated portion formed by laminating a plurality of the second green sheets are formed, and the laminated body is baked to form the first and second layers. A ceramic substrate is formed by burning out the burned material.

  Thereby, the average value of the diameter of the void | hole of a 1st ceramic element part and a 2nd ceramic element part can be varied easily.

  As described above, according to the ceramic electronic component and the method for manufacturing the same according to the present invention, the dielectric constant and the permeability can be increased by filling the pores of the first ceramic element portion and the second ceramic element portion with different filling materials. Characteristics such as magnetic susceptibility can be made different, and different characteristics can be obtained in each part of the ceramic substrate without simultaneous firing of different materials.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view schematically showing a laminated LC filter as an example of a ceramic electronic component according to the present invention.

  This ceramic electronic component generally includes a ceramic base 10 made of a magnetic material, and a ground external electrode 21 and a signal external electrode 22 formed on the surface of the ceramic base 10. The ceramic base 10 is formed by integrating a first ceramic element portion 11 and a second ceramic element portion 12.

  A coil conductor 31 is built in the first ceramic element portion 11, one end of the coil conductor 31 is connected to the signal external electrode 32, and the other end is drawn out to the second ceramic element portion 12. It is.

  The second ceramic element portion 12 includes a first capacitor conductor 41 that is electrically connected to the coil conductor 31 and a second capacitor conductor 42 that is connected to the grounding external electrode 21. A capacitor is obtained between the capacitor conductor 41 and the second capacitor conductor 42.

  That is, a T-type LC filter is composed of two coils and one capacitor.

  FIG. 2A is an enlarged cross-sectional view showing the first ceramic element portion 11, and FIG. 2B is an enlarged cross-sectional view showing the second ceramic element portion 12. A first hole 51 is formed in the first ceramic element portion 11, and a first filling material 61 made of an epoxy resin is filled in the first hole 51. The average diameter of the first holes 51 is 80 μm. Since the relative dielectric constant of the magnetic material constituting the ceramic substrate 10 is about 15, whereas the relative dielectric constant of this epoxy resin is 3.4, the first void 51 is formed to form the first By filling the filling material 61, the effective dielectric constant is lowered.

The second ceramic element portion 12 has a second hole 52 formed therein, and the second hole 52 is filled with a second filling material 62. The average value of the diameters of the second holes 52 is 6.5 μm. The second filling material 62 is a composite resin material in which an epoxy resin and a BaTiO ₃ dielectric ceramic powder are mixed, and has a relative dielectric constant of 200. By filling the second filling material 62 having a dielectric constant higher than that of the magnetic material, the effective dielectric constant is increased.

  Thereby, although the first ceramic element portion 11 and the second ceramic element portion 12 are made of the same magnetic material, the first ceramic element portion 11 reduces the effective dielectric constant. The stray capacitance can be reduced, and the second ceramic element portion 12 can increase the effective dielectric constant and obtain a large capacitance.

  In FIGS. 2A and 2B, the first and second holes 51 and 52 are filled with the first and second filling materials 61 and 62. It is not necessary to be at least partially filled. However, in the second ceramic element portion 12, when the filling rate of the second filling material 62 is too low, the relative permittivity of air is 1, so that the permittivity may be lowered. It is necessary to use a filling rate.

  Next, a method for manufacturing the ceramic electronic component will be described. FIG. 3 is an exploded perspective view showing a ceramic electronic component according to the present invention.

First, a metal oxide such as Fe ₂ O ₃ , NiO, CuO, ZnO is mixed, calcined at 800 ° C. for 1 hour, and pulverized by a ball mill, so that the average particle diameter of Ni—Cu—Zn ferrite is about 2 μm. A ceramic raw material powder was obtained.

  Next, a ceramic slurry is prepared by mixing a ceramic raw material powder, a first burned-out material made of spherical cross-linked polystyrene having an average particle size of 100 μm, a solvent, a binder, and a dispersant, and using this ceramic slurry by a doctor blade method A first ceramic green sheet having a thickness of 40 μm was obtained.

  Further, a ceramic slurry is prepared by mixing the ceramic raw material powder, a second burned material having an average particle diameter of 8 μm made of spherical cross-linked polystyrene, a solvent, a binder, and a dispersant, and using this ceramic slurry by a doctor blade method A second ceramic green sheet having a thickness of 40 μm was obtained.

  In addition, although the crosslinked polystyrene is used as the first and second burnout materials, the burnout material may be any as long as it burns away in the subsequent firing step and has adhesiveness to the binder. Specifically, in addition to crosslinked polystyrene, crosslinked polymethyl methacrylate, crosslinked polybutyl methacrylate, crosslinked polymethacrylic acid ester, crosslinked polyacrylic acid ester, and the like can be used.

  In addition, if there is no difference between the average particle diameters of the first burned material and the second burned material above a certain level, the filling material may not be selectively filled in the subsequent first and second filling steps. Therefore, the average particle size of the first burned material is preferably about 10 times the average particle size of the second burned material.

  Furthermore, the blending ratio of the first and second burnout materials is preferably 30 to 80 vol% in the ceramic slurry. When the blending ratio is less than this, the filling amounts of the first and second filling materials are reduced, and it is difficult to sufficiently obtain the effect of lowering or raising the dielectric constant. Moreover, when there are more compounding ratios, it will become difficult to shape | mold a ceramic slurry to a green sheet.

  Next, the ceramic green sheet 71 is obtained by forming the via hole 43 in the first ceramic green sheet, and the ceramic green sheet 72 is obtained by forming the via hole 43 and the coil conductor 31 in the first ceramic green sheet.

  Further, the via hole 43 and the first capacitor conductor 41 are formed on the second ceramic green sheet to obtain the ceramic green sheet 81, and the second capacitor conductor 42 is formed on the second ceramic green sheet to form the ceramic green sheet. Get 82. The first capacitor conductor 41 is electrically connected to the coil conductor 31 through the via hole 43. The second capacitor conductor 42 is insulated from the via hole 43, and its end is drawn out to the end of the ceramic green sheet 82.

  The via hole 43 is formed by forming a through hole in the first or second ceramic green sheet with a laser processing apparatus or the like, and filling the through hole with a conductive paste mainly composed of Ag or the like. The coil conductor 31 and the first and second capacitor conductors 41 and 42 are formed by printing a conductive paste mainly composed of Ag on the first or second ceramic green sheet by a method such as screen printing. Form.

  Next, the ceramic green sheets 71, 72, 81, 82 are laminated in a predetermined order shown in FIG. 3 to obtain a laminate. At this time, a region where the ceramic green sheets 71 and 72 formed by processing the first ceramic green sheets are stacked is the first green sheet stacking portion 70, and the second ceramic green sheets 81 and 82 are processed. The region where the ceramic green sheets are stacked is the second green sheet stacking portion 80.

  Next, the laminate is heat-treated at 400 ° C. for 3 hours to remove the binder, and fired at 900 ° C. for 2 hours to obtain the ceramic substrate 10 (see FIG. 1). At this time, the first green sheet laminate portion 70 becomes the first ceramic element portion 11, and the second green sheet laminate portion 80 becomes the second ceramic element portion 12. The first ceramic element portion 11 has a first hole 51 formed by burning out the first burned material. Further, the second ceramic element portion 12 is formed with a second hole 52 formed by burning out the second burnout material.

  Next, a conductive paste mainly composed of Ag is baked on the surface of the ceramic substrate 10 to form the grounding external electrode 21 and the signal external electrode 22. The grounding external electrode 21 is formed on the second ceramic element portion 12 and is electrically connected to the second capacitor conductor 42. The signal external electrode 22 is formed on the first ceramic element portion 11 and is electrically connected to the end portion of the coil conductor 31 via the via hole 43.

  Next, the ceramic base 10 is immersed in the epoxy resin that is the first filling material 61 in the decompression device, the pressure is reduced to 50 kPa, and the first holes 51 are placed in the first holes 51 as shown in FIG. One filling material 61 is filled (first filling step). At this time, since the degree of vacuum is low, the second filling holes 52 having a small average particle diameter are hardly filled with the first filling material 61. In the first filling step, it is preferable to reduce the pressure to about 30 to 70 kPa. If the atmospheric pressure is higher than this, the first filling material 61 may not be sufficiently filled in the first hole 51. If the atmospheric pressure is lower than this, the first filling up to the second hole 52 may occur. There is a possibility that the material 61 is filled. The relative dielectric constant of the epoxy resin used here is 3.4.

  Next, the ceramic base 10 was immersed in an organic solvent to remove the first filling material 61 adhering to the surface of the ceramic base 10 and heated to 150 ° C. to cure the epoxy resin.

Next, the ceramic base 10 is immersed in the second filling material 62 in a decompression device, the pressure is reduced to 1.5 kPa, and the second holes 52 are filled with the second pressure as shown in FIG. Filling material 62 is filled (second filling step). Thus, the first hole 51 is selectively filled with the first filling material 61, and the second hole 52 is selectively filled with the second filling material 62. In the second filling step, it is preferable to reduce the pressure to about 0.5 to 1.5 kPa. If the atmospheric pressure is higher than this, the second filling material 62 may not be sufficiently filled in the second holes 52. Further, even if the atmospheric pressure is lower than this, there is no difference in the degree of filling. The second filling material 62 used here is a composite resin material prepared by mixing BaTiO ₃ -based dielectric ceramic powder and an epoxy resin so that the relative dielectric constant becomes 200.

  Next, the ceramic base 10 is immersed in an organic solvent, and the second filling material 62 adhering to the surface of the ceramic base 10 is removed as shown in FIG. 4C, and the composite resin is heated to 150 ° C. The material was cured.

  Next, Ni plating and Sn plating are sequentially applied to the grounding external electrode 21 and the signal external electrode 22 to complete the ceramic electronic component shown in FIG.

  In the embodiment, the T-type laminated LC filter has been described as an example, but the present invention is not limited to this. For example, it may be a π-type LC filter, a ceramic electronic component incorporating an LC resonance circuit, or a ceramic electronic component incorporating a plurality of coils having different characteristics.

  In the above embodiment, materials having different dielectric constants are used as the first and second filling materials. However, materials having different characteristics other than the dielectric constant, such as materials having different magnetic permeability, may be selected.

It is sectional drawing which shows the ceramic electronic component which concerns on this invention. It is an expanded sectional view which shows the ceramic electronic component which concerns on this invention. It is a disassembled perspective view which shows the ceramic electronic component which concerns on this invention. It is sectional drawing which shows a part of manufacturing process of the ceramic electronic component which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ceramic base | substrate 11 1st ceramic element part 12 2nd ceramic element part 21 Grounding external electrode 22 Signaling external electrode 31 Coil conductor 41 1st capacitor conductor 42 2nd capacitor conductor 51 1st hole 52 1st 2 holes 61 first filling material 62 second filling material 70 first green sheet laminate 80 second green sheet laminate 71, 72, 81, 82 ceramic green sheet

Claims (5)

An electronic component having a ceramic substrate in which first and second ceramic element portions are integrally formed,
The first ceramic element portion has a first hole, and at least a part of the first hole is filled with a first filling material;
A second hole is formed in the second ceramic element portion, and at least a part of the second hole is filled with a second filling material;
The ceramic electronic component according to claim 1, wherein the first hole and the second hole have different average diameter values.   2. The ceramic electronic component according to claim 1, wherein a coil conductor is built in the first ceramic element part, and a capacitor conductor is built in the second ceramic element part.   The ceramic base is made of a magnetic material, the first filling material has a dielectric constant smaller than that of the magnetic material, and the second filling material has a dielectric constant larger than that of the magnetic material. The ceramic electronic component according to claim 2, wherein A ceramic substrate in which a first ceramic element portion having a first hole and a second ceramic element portion having a second hole having a smaller diameter than the first hole are integrally formed is prepared. A ceramic substrate preparation process;
A first filling step of filling the first pores with a first filling material;
A second filling step of filling the second pores with a second filling material,
In the second filling step, the second filling material is filled by reducing the pressure to a pressure lower than that in the first filling step.   In the ceramic base preparation step, a first ceramic green sheet is produced using a ceramic slurry containing a ceramic raw material powder and a spherical first burned material, and the ceramic raw material powder and the spherical and first burned material are prepared. A first green sheet laminate formed by laminating a plurality of the first ceramic green sheets by using a ceramic slurry containing a second burned-out material having an average diameter smaller than that of the second ceramic green sheet. And a second green sheet laminate part formed by laminating a plurality of the second green sheets, and firing the laminate to produce the first and second burnouts. 5. The method of manufacturing a ceramic electronic component according to claim 4, wherein the ceramic substrate is formed by burning out the material.

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