KR100232547B1 - Composite lc part and composite lc chip part - Google Patents

Abstract

A composite magnetic material obtained by sintering a mixture of a dielectric material and a magnetic material, and containing a third material for suppressing the chemical reaction between the dielectric material and the magnetic material at the time of sintering the mixture and lowering the sintering temperature. The present invention relates to a composite magnetic material, in particular an EMI filter, an LC composite component, and an LC composite chip component, wherein both ends of the bare chip are exposed at the beginning and end of the inductor, and a signal electrode is installed there. One end of the grounding conductor is alternately exposed to each other on both ends of the bare chip, and the grounding electrode is installed there. The conductor for the inductor is configured to form an inductor by connecting in series in a spiral shape in the thickness direction of the bare chip via through holes formed as sheets in the bare chip. The grounding conductor is adjacent to the inductor conductor in the plane of the bare chip at a distance insulated from the inductor conductor in the same plane, and is configured to form a capacitor between the inductor conductor and the inductor conductor through the sheet. .

Description

Inductance-capacitance composite part and Inductance-capacitance composite chip part {COMPOSITE LC PART AND COMPOSITE LC CHIP PART}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a composite magnetic material, comprising a composite ceramic useful as an electronic component material, in particular an electromagnetic interference filter (hereinafter referred to as EMI filter), an inductance-capacitance composite component (hereinafter referred to as LC composite component), and inductance-capacitance A composite chip component (hereinafter referred to as LC composite chip component).

In the field of electronic components, dielectric materials and magnetic materials occupy a large role, the former is mainly used as a capacitor material, the latter is mainly used as an inductor material, and capacitors and inductors are manufactured by respective materials. .

By the way, conventional EMI filters used in signal lines and the like are generally manufactured by combining individual elements of these capacitors and inductors. However, in the conventional EMI filter formed by combining individual elements of a capacitor or an inductor, the product can not be miniaturized.

In order to solve such a problem, a test for manufacturing an EMI filter having a capacitance and an inductance is conventionally performed using a composite magnetic material obtained by mixing and sintering a dielectric material and a magnetic material.

However, when the dielectric material and the magnetic material are mixed and sintered at high temperature, in general, the dielectric material and the magnetic material react during this sintering, resulting in inconvenience such as deterioration of each characteristic or damage of sintering reproducibility. There was a ham. In addition, there is also the inconvenience of degrading the characteristics of the EMI filter or damaging reproducibility.

Background Art Conventionally, LC composite parts and LC composite chip parts having a monolithic structure in which an inductor and a capacitor are combined are proposed. For example, the present applicant alternately prints and laminates a ceramic layer of a dielectric and a conductor for a capacitor to form a laminate for a capacitor, and alternately a magnetic ceramic layer and a conductor for an inductor on or separately from the laminate for the capacitor. Printed lamination to make inductor laminates, these capacitors and inductor laminates are sintered integrally in multiple layers with intermediate layers interposed therebetween, and suitable external terminals at exposed ends of the inner conductors. The installed LC composite part was proposed (for example, Japanese Patent Laid-Open No. 3-166810). In the inductor laminate of the LC composite part, the inductor conductor formed on the ceramic layer is connected to each layer via a through hole provided in the ceramic layer, whereby an inductor spiral in the thickness direction of the laminate is formed. do.

In addition, as another LC composite part, the applicant integrates a laminated chip inductor having an internal electrode provided inside a ferrite sintered body, and a laminated chip capacitor having an internal electrode and a grounded electrode formed inside the dielectric sintered body by an adhesive. Patent application of π-type LC filter that electrically connects each external electrode of inductor and multilayer chip capacitor (Patent No. 6-325977).

Furthermore, the ceramic layer constituting the laminate for inductor and the ceramic layer constituting the laminate for capacitor are made together with ceramic dielectric materials, and the sintered integrally sintered integrally in the state where these laminates for inductor and capacitor laminate are stacked in multiple layers. In addition, LC composite parts with appropriate external terminals on the exposed ends of the internal conductors are also tested.

However, in the LC composite part disclosed in Japanese Patent Laid-Open No. 3-166810, the thermal contraction rate of the capacitor laminate differs from that of the inductor laminate. Therefore, thermal stress is generated from the difference of the thermal contraction rate during sintering. Even through the intermediate layer, there are deformations, cracks, and characteristic changes due to thermal stress, and there are disadvantages inferior in yield and reliability as products.

In addition, while the π-type LC filter of Japanese Patent Application Laid-Open No. 6-325977 does not have the above-described drawbacks, it is necessary to sinter the laminated chip inductor and the laminated chip capacitor separately, and the production management of the chip inductor and chip capacitor is cumbersome. The dimensions were also inconvenient to be difficult to miniaturize.

Moreover, LC composite parts composed of dielectrics alone cannot take sufficient inductance when used for noise reduction, and besides, dielectrics are always sandwiched between the windings of the coil pattern forming the inductor, thus increasing the floating capacity between the windings. There was a problem that performance could not be obtained.

An object of the present invention is to solve the above-mentioned conventional problems, to suppress the reaction of dielectric materials and magnetic materials during sintering as much as possible, and to provide a composite magnetic material without deterioration of characteristics.

An object of the present invention is to solve the above-mentioned conventional problems, to suppress the reaction of dielectric materials and magnetic materials at the time of sintering as much as possible, and to provide an EMI filter having excellent reproducibility of characteristics without problems such as deterioration of characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide an LC composite part and an LC composite chip part which suppress the thermal stress at the time of sintering to a very small level and have little deformation, cracking and characteristic variation.

Another object of the present invention is to provide an LC composite part and an LC composite chip part having a small stray capacitance between windings of a coil pattern forming an inductor and excellent in noise removal.

It is still another object of the present invention to provide an LC composite part and an LC composite chip part which can be surface-mounted on a printed circuit board or the like and have a small size and high productivity.

The composite magnetic material of the present invention is a composite magnetic material obtained by sintering a mixture of a dielectric material and a magnetic material, which suppresses chemical reaction between the dielectric material and the magnetic material at the time of sintering the mixture, and at the same time, the sintering temperature It characterized in that it contains a third material for lowering.

The third material is preferably a CdO-ZnO-B ₂ O ₃ -based material.

In the present invention, a third material is added to the sintered raw material, and the third material suppresses the chemical reaction between the dielectric material and the magnetic material during sintering, lowers the sintering temperature, and further lowers the dielectric material by low temperature sintering. To prevent chemical reactions of

The EMI filter of the present invention is an EMI filter in the form of a three-terminal condenser made of a mixed sintered body of a dielectric material and a magnetic material. The mixed sintered body suppresses the chemical reaction between the dielectric material and the magnetic material during sintering. And a third material for lowering the sintering temperature.

The third material to be used in the present invention may be one capable of suppressing the chemical reaction between the dielectric material and the magnetic material during sintering and reducing the sintering temperature, and the type (composition) of the dielectric material and magnetic material to be used. Although it also varies depending on the usage ratio and the like, the following are preferably listed.

That is, CdO, ZnO, and B ₂ O ₃ as the third material,

CdO: 10-40 mol%

ZnO: 30-60 mol%

B ₂ O ₃ : 10-40 mol%

Preferred is a CdO-ZnO-B ₂ O ₃ -based material obtained by firing at a ratio of 600 to 1000 ° C.

In the present invention, the material composition of the dielectric material and the magnetic material, the combination of the dielectric material and the magnetic material, the mixing ratio and the like are not particularly limited, and are determined according to the purpose of use of the composite magnetic material to be manufactured and the like.

Generally, a dielectric material is a relaxer type material, and as a magnetic material, Ni-Zn ferrite or Ni-Zn-Cu ferrite is suitable.

Specific dielectric materials and magnetic materials are listed below.

_{(PbO x · La 2 O 3y} / 2) · (ZrO u · TiO v)

x + y = 1 (x = 0.80 to 0.99)

u + v = 1 (u = 0.50 to 0.85)

(NiO _x ZnO _y CuO _z ) _a (Fe ₂ O ₃ ) _b

x + y + z = a a = 0.505 to 0.530

x = 0.10 to 0.35 b = 0.495 to 0.470

y = 0.10 to 0.35 a + b = 1

z = 0.00 to 0.20

The mixing ratio of the dielectric material and the magnetic material also varies depending on the dielectric constant of the dielectric material, the magnetic permeability of the magnetic material, and the like, but it is preferable to set the dielectric material in the range of 20 to 80% by weight and the magnetic material to 20 to 80% by weight. .

When the addition ratio of the above-mentioned third material to these dielectric materials and magnetic materials is excessive, the properties of the composite magnetic material and the EMI filter obtained may be impaired, and if too small, the addition of the third material may be sufficient. Since the improvement effect is not obtained, it is preferable that the third material is 0.05 to 3% by weight, particularly about 0.1 to 2% by weight, based on the sum of the dielectric material and the magnetic material.

The composite magnetic material and EMI filter of the present invention can be produced by mixing a dielectric material powder, a magnetic material powder, a third material powder and the like at a predetermined ratio, and sintering the obtained mixed powder at 850 to 1000 占 폚.

By mixing the third material, the chemical reaction between the dielectric material and the magnetic material during sintering is prevented, and the low temperature sintering is effected by the effect of reducing the sintering temperature by the third material. It is further suppressed, and as a result, the dielectric material and the magnetic material hardly cause chemical reaction during sintering.

The structure of the LC composite part of this invention is demonstrated using FIG. 2 corresponding to an Example. In the LC composite part 10 of the present invention, a plurality of green sheets 11 to 16 made of a composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio are used as a part of the inductor 12 to 16 for the inductor. After the conductors 22 to 26 and the grounding conductors 32 to 36 are formed to be electrically insulated and laminated, the bare chips 41 sintered mainly in the form of chips are mainly used. The inductor conductors 22 to 26 are configured to form an inductor by connecting spirally in the thickness direction of the bare chip 41 through the through holes 12a to 15a formed in the sheets 12 to 15 inside the bare chip. The tip end 22a is exposed to the first end face of the bare chip 41 and the end end 26a is exposed to the second end face of the bare chip 41. The grounding conductors 32 to 36 are adjacent to each other at intervals insulated from the inductor conductors 22 to 26 with the inductor conductors 22 to 26 within the bare chip in the same plane. It is configured to form a capacitor between the inductor conductors 22 to 26 via the inductor conductors 22 to 26, and one end 32a to 36a of the third and fourth ends of the bare chip 41. Expose to cross section. The first and second signal electrodes 42 and 43 electrically connected to the start end 22a and the end 26a of the inductor conductor exposed to the first and second end faces of the bare chip 41 respectively. First and second ground electrodes 44 provided at the first and second end surfaces and electrically connected to one ends 32a to 36a of the grounding conductor exposed to the third and fourth end faces of the bare chip 41. , 45 are provided on the third and fourth end faces.

In the LC composite part 10, since the inductor and the capacitor are formed by using the green sheet made of the same ceramic material, the process can be simplified, and the thermal stress during sintering can be reduced to a very small level. Trouble such as cracking or cracking can be avoided.

In addition, since the grounding conductors are arranged in the same plane as the inductor conductors or vertically adjacent to the inductor conductors, the inductors formed by these inductor conductors have extremely low stray capacitance. Since a plurality of capacitors are formed between the conductor and each grounding conductor, it can be used to remove noise of a wide frequency.

The structure of the LC composite chip component of this invention is demonstrated using FIG. 6 corresponding to an Example.

In the LC composite chip component 110 of the present invention, a plurality of green sheets 111 to 116 made of a composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio are inducted into portions 112 to 116. After forming and stacking the conductors 122 to 126 and the ground conductors 133 and 135 so as to electrically insulate, the bare chips 141 sintered using the laminate as a chip are mainly used.

The inductor conductors 122 to 126 are formed in an S-shape at the cut surface in the thickness direction of the bare chip 141 via the through holes 112a to 115a formed in the sheets 112 to 115 inside the bare chip 141. And the end end 122a is exposed to the first end face of the bare chip 141, and the end end 126a is exposed to the second end face of the bare chip 141.

The grounding conductors 133 and 135 overlap with the inductor conductors 122 to 126 via the sheets 112 to 115 inside the bare chip to form a capacitor between the inductor conductors 122 to 126. Both ends 133a, 133b, 135a, and 135b are exposed to the third and fourth end surfaces of the bare chip 141 described above.

The first and second signal electrodes 142 and 143 electrically connected to the start end 122a and the end 126a of the inductor conductor exposed to the first and second end faces of the bare chip 141, respectively. It is installed on the first and second end faces.

First and second grounding electrodes 144 electrically connected to both ends 133a, 133b, 135a, and 135b of the grounding conductor exposed to the third and fourth cross-sections of the bare chip 141. ), 145 is installed on the third and fourth end surfaces.

In addition, in the LC composite chip component described above, a plurality of green sheets 111 to 116 made of a ceramic material composed only of dielectric ceramic powder are replaced by a composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio. The inductor conductors 122 to 126 and the ground conductors 133 and 135 are electrically insulated from and laminated on the 112 to 116, and the bare chips 141 sintered in the form of chips are stacked. ) May be mainly used. In this LC composite chip component, since the inductor and the capacitor are formed by using the green sheets 112 to 116 made of the same ceramic material, the process can be simplified, and the thermal stress during sintering can be reduced to a very small level. Trouble such as deformation or cracking in the chip 141 can be avoided.

In addition, the grounding conductors 133 and 135 are disposed adjacent to the inductor conductors 122 to 126 in the same plane or vertically adjacent to the inductor conductors 122 to 126. The inductors formed in S-shape on the cut surface in the thickness direction by the conductors 122 to 126 have extremely low stray capacitance, and furthermore, the inductors 122 to 126 and the ground conductors 133 and 135 Since capacitors are formed between them, they can be used for noise cancellation at a wide range of frequencies.

Further, the inductance and capacitance can be increased or decreased by changing the current path of the inductor conductor, which is the signal line conductor, in proportion to the number of stacked green sheets.

1 is a perspective view of an electromagnetic interference filter chip.

2A is a perspective view of a green sheet before lamination of the inductance-capacitance composite component of the present invention.

Figure 2 (b) is a perspective view of the inductance-capacitance composite part.

3 is a cross-sectional view taken along the line A-A of FIG. 2 (b).

4 is a cross-sectional view taken along the line B-B in FIG. 2 (b).

5 is an equivalent circuit diagram thereof.

6A is a perspective view of a green sheet before lamination of the inductance-capacitance composite chip component of the present invention.

6B is a perspective view of the inductance-capacitance composite chip component.

7 is a cross-sectional view taken along the line A-A of FIG. 6 (b).

8 is an equivalent circuit diagram thereof.

-Explanation of symbols for the main parts of the drawing-

(1) --------------------------------- self-sintering,

(2) --------------------------------- grounding electrode,

(3) --------------------------------- signal electrode,

(10) --------------------------- Inductance-Capacitance

Composite parts,

(11) ~ (16) -------------------------- Green Sheet,

(12a) to (15a) ------------------------ Through Hole,

(22)-(26) -------------------------- Inductors,

(22a) ------------------------------- Inductor start,

(26a) ------------------------------- Inductor Termination,

(32)-(36) -------------------------- Grounding conductor,

(32a) to (36a) ------------------------ One end of the grounding conductor,

(41) -------------------------------- Bare chips,

(42), (43) --------------------------- Signal electrode,

(44), (45) --------------------------- Grounding electrode.

The following describes the present invention in more detail by listing examples and comparative examples. As the dielectric material and the magnetic material, those produced as follows were used.

Dielectric materials: PbO, La ₂ O ₃ , ZrO ₂ , TiO ₂ as starting materials, mixed them at a ratio of 88: 6: 70: 30 (molar ratio), respectively, and then calcined at 1150 ° C., Pb _0.88 La _0.12 Zr _0.7 A dielectric material of Ti _0.3 O _3.06 was obtained.

Magnetic materials: NiO, ZnO, CuO, Fe ₂ O ₃ as starting materials, these were mixed at a ratio of 24: 22: 6: 48 (molar ratio), respectively, and fired at 1000 ° C. Ni _0.24 Zn _0.22 Cu _0.06 Fe A magnetic material of _0.96 O _1.96 was obtained.

(Examples 1 to 5)

CdO, ZnO, and B ₂ O ₃ were used as starting materials, and these were mixed at the ratios shown in Table 1, respectively, and calcined at 900 ° C. to obtain third materials of CdO—ZnO—B ₂ O ₃ based systems.

This third material was mixed with a dielectric material and a magnetic material at a ratio shown in Table 1, and sintered at the temperature shown in Table 1 to obtain a composite magnetic material.

X-ray diffraction patterns of the obtained composite magnetic materials were examined. In all cases, patterns of magnetic and dielectric materials were observed, and no peaks of other unknown materials that both seemed to react with were observed. I couldn't.

(Comparative Example 1)

In Example 1, the production of the composite magnetic material was conducted in the same manner except that no third material was used. As a result, a composite magnetic material that could not be sufficiently sintered and was commercialized could not be obtained.

In addition, by examining the X-ray diffraction pattern of the obtained composite magnetic material, peaks of unknown materials other than the dielectric material and the magnetic material were confirmed.

(Comparative Example 2)

In Example 1, a composite magnetic material was produced in the same manner as in Table 1 without using the third material, except that the sintering temperature was raised and calcined.

As a result, although sintering was carried out, a large number of peaks of unknown materials other than the dielectric material and the magnetic material were confirmed by examining the X-ray diffraction pattern.

(Examples 6-9)

CdO, ZnO, and B ₂ O ₃ were used as starting materials, and these were mixed at the ratios shown in Table 2, respectively, and calcined at 900 ° C. to obtain third materials of CdO—ZnO—B ₂ O ₃ based systems.

The third material is mixed with the dielectric material and the magnetic material at the ratio shown in Table 2, and kneaded by adding 10% by weight of a binder (polyvinyl butyral) to the obtained mixture, and mixed by a doctor blade method to a thickness of 30 µm. A ceramic sheet was produced. 50 sheets of this ceramic sheet were stacked, and internal electrodes (ground electrode, signal electrode) were printed, hot-pressed, and cut in the middle to obtain a three-terminal capacitor-shaped EMI filter chip shown in FIG. In Fig. 1, reference numeral 1 denotes a magnetic sintered material, reference numeral 2 denotes a ground electrode, and reference numeral 3 denotes a signal electrode.

After sintering 1000 chips for 2 hours at the temperature shown in Table 2, the terminal electrode was attached to measure the capacitance between the ground electrode and the signal electrode. In addition, impedance at both ends of the signal electrode was measured. The measurement results are as shown in Table 2, and in all cases, a highly characteristic EMI filter with good reproducibility was obtained.

In addition, X-ray diffraction patterns of the ceramic parts of the obtained chips were examined. In all cases, patterns of only magnetic and dielectric materials were observed, and no peaks of other unknown materials that were observed to react were found at all. .

(Comparative Example 3)

In Example 1, except that the third material was not used at all, the chip was tested in the same manner, and the chip was not sufficiently sintered, and the characteristics thereof were also markedly poor as shown in Table 2, I couldn't get a chip.

In addition, by examining the X-ray diffraction pattern of the ceramic part of the obtained chip, peaks of unknown materials other than the dielectric material and the magnetic material were confirmed.

(Comparative Example 4)

In Example 1, a chip was produced in the same manner as in Table 2 without using the third material, except that the sintering temperature was raised and calcined.

As a result, the sintering was performed, but the characteristics and reproducibility of the obtained chip were remarkably poor as shown in Table 2, and the X-ray diffraction pattern of the ceramic part of the chip was investigated. A large number of peaks were identified.

Next, an LC composite part and an LC composite chip part according to an embodiment of the present invention will be described in detail with reference to the drawings.

The LC composite part of this embodiment is made by laminating a plurality of green sheets made of a starting material of a composite ceramic material obtained by mixing a magnetic ferrite powder and a dielectric ceramic powder in a predetermined ratio, and sintering the laminate in a chip form. This composite ceramic material is a composite functional material with constant permeability and permittivity.

In the present Example, each powder of NiO, ZnO, CuO, and Fe ₂ O ₃ was weighed to a predetermined ratio as a magnetic ferrite powder, and then wet mixed. The mixture was calcined at 1000 ° C. for 2 hours, and then ground by a wet mill to prepare a magnetic ferrite powder having an average particle diameter of about 0.1 μm. This composition was Ni _0.24 Zn _0.22 Cu _0.06 Fe _0.96 O _1.96 . As the dielectric ceramic powder, each powder of PbO, La ₂ O ₃ , ZrO ₂ , and TiO ₂ was weighed to a predetermined ratio, and then mixed in a wet manner. After the mixture was calcined at 1150 ° C. for 2 hours, it was ground with a wet mill, and a dielectric ceramic powder having an average particle diameter of about 0.1 μm was prepared. This composition was Pb _0.88 La _0.12 Zr _0.7 Ti _0.3 O _3.06 .

When the prepared magnetic ferrite powder and the dielectric ceramic powder are mixed in a weight ratio of 60:40, a composite ceramic material having a sintering temperature of about 1030 ° C is obtained. In addition, it is preferable that the mixing ratio of the magnetic ferrite powder and the dielectric ceramic powder is appropriately selected from the range of 60 to 40:40 to 60. Moreover, in order to suppress reaction between the material of the magnetic ferrite powder and the dielectric ceramic powder at the time of sintering, and to reduce a sintering temperature, it is preferable to add an improvement material. This improved material is, for example, CdO-ZnO-B ₂ O ₃ as a composition system, mixed with CdO, ZnO, and B ₂ O ₃ in a molar ratio of 1: 1: 1, and then calcined at 900 ° C for 1 hour, and then pulverized with a grinder. Obtained, and an average particle diameter is about 0.1 micrometer powder. In this embodiment, the magnetic ferrite powder, the dielectric ceramic powder and the improved material were mixed in a weight ratio of 60: 40: 1.5 to obtain a composite ceramic material having a sintering temperature of about 950 ° C.

Next, the obtained composite ceramic material is mixed with a binder and a binder solvent which can be gasified at the time of sintering using a grinder to prepare a slurry, and the slurry is formed into a green sheet by a doctor blade method. In addition, this sheet is kneaded with a composite ceramic material, a binder, and a solvent for a binder, and it can also be made by the printing method using this paste.

A plurality of green sheets thus obtained are laminated. On the surface of some green sheets, a conductive paste is applied by screen printing to form an electrical insulator between the inductor conductor and the ground conductor. Through-holes are drilled at the interconnection positions of the inductor conductors of the green sheet, and a predetermined number of sheets are laminated while filling the through-holes with conductive paste as necessary. The obtained laminate is press-molded, cut into chips, and fired into bare chips.

As shown in Fig. 2A, in this case, for the sake of simplicity, an example in which six green sheets 11 to 16 are stacked is listed. Nothing is printed on the first green sheet 11, and no conductor is formed. On the surfaces of the second to sixth green sheets 12 to 16, the inductor conductors 22 to 26 and the grounding conductors 32 to 36 are formed at intervals insulated from each other. Through-holes 12a to 15a for connecting with the lower inductor conductors are drilled at the ends of the inductor conductors 22 to 25 of the second to fifth green sheets 12 to 15, and the five inductor conductors. When the layers 22 to 26 are laminated, they are connected in series in a spiral shape in the thickness direction to form an inductor. One end 22a of the inductor conductor 22 of the second green sheet 12 extends to the edge of the green sheet 12 as the start of the inductor. One end 26a of the inductor conductor 26 of the sixth green sheet 16 extends to the other end edge of the green sheet 16 as the end of the inductor. The grounding conductors 32 to 36 are adjacent to the inductor conductors 22 to 26, and one end 32a to 36a alternately extends to the side edges of the green sheets 12 to 16, respectively.

When these green sheets 11-16 are laminated | stacked and baked, the sintered bare chip | tip 41 of a rectangular parallelepiped is obtained. As shown in FIG. 2 (b), FIG. 3 and FIG. 4, one end 22a of the inductor conductor 22 serving as the start of the inductor is exposed on the first end face of the bare chip 41, Although not shown in the second cross section, one end 26a of the inductor conductor 26 as an end of the inductor is exposed. Similarly, ends 32a to 36a of the grounding conductors 32 to 36 are alternately exposed to the third and fourth end surfaces of the bare chip 41. Signal electrodes 42 and 43 are formed by applying a conductive paste to the first and second end surfaces, and ground electrodes 44 and 45 are similarly formed on the third and fourth end surfaces. do. As a result, the LC composite component 10 is obtained.

The five inductor conductors 22 to 26 are connected in series through the through holes 12a to 15a in the bare chip 41 to form an inductor, and the five grounding conductors 32 to 36 are sheets. The capacitors are formed between the inductor conductors 22 to 26 via the inductor conductors 12 to 15 to overlap with the inductor conductors. This equivalent circuit is shown in FIG.

Next, embodiments of LC composite chip components will be described in detail with reference to the drawings.

The LC composite chip component of this embodiment is made by laminating a plurality of green sheets made of a starting material of a composite ceramic material obtained by mixing a magnetic ferrite powder and a dielectric ceramic powder at a predetermined ratio, and sintering the laminate in a chip shape. . This composite ceramic material is a composite functional material with constant permeability and permittivity.

In this embodiment, the same material as in the above embodiment of the LC composite part was used.

As shown in Fig. 6 (a), in this case, for the sake of simplicity, an example in which six green sheets 111 to 116 are stacked is listed. Nothing is printed on the first green sheet 111, and no conductor is formed. Inductors 122, 124, and 126 are formed on the surfaces of the second, fourth, and sixth green sheets 112, 114, and 116, and the third and fifth greens are formed. Surfaces of the sheets 113 and 115 are formed at intervals in which the inductor conductors 123 and 125 and the grounding conductors 133 and 135 are electrically insulated from each other.

Through-holes 112a to 115a for connecting with the inductor conductors in the lower layer are drilled at the ends of the inductor conductors 122 to 125 of the second to fifth green sheets 112 to 115, and the five inductor conductors are formed. 122 to 126 are connected in series in an S-shape at the cut surface in the thickness direction thereof to form an inductor. One end 122a of the inductor conductor 122 of the second green sheet 112 extends to the edge of the green sheet 112 as the start of the inductor. One end 126a of the inductor conductor 126 of the sixth green sheet 116 extends to the other end of the green sheet 116 as the end of the inductor.

The grounding conductors 133 and 135 are formed adjacent to the inductor conductors 123 and 125, with the green sheets 112 to 115 interposed therebetween, and the other inductor conductors 122 and 124. It is configured to overlap with (126). One end 133a, 135a and the other ends 133b, 135b of the grounding conductors 133, 135 extend to two opposite side edges of the green sheets 113, 115, respectively.

When these green sheets 111-116 are laminated and sintered, the sintered bare chip | tip 141 of a rectangular parallelepiped is obtained. As shown in Figs. 6B and 7, one end 122a of the inductor conductor 122 serving as the start end of the inductor is exposed on the first end face of the bare chip 141, and the second end face is exposed on the second end face. Although not shown, one end 126a of the inductor conductor 126 at the end of the inductor is exposed. Similarly, one end 133a, 135a and the other end 133b, 135b of the grounding conductors 133 and 135 are exposed on the third and fourth end surfaces of the bare chip 141. Signal electrodes 142 and 143 are formed by applying and pasting a conductive paste on the first and second end surfaces, and grounding electrodes 144 and 145 are similarly formed on the third and fourth end surfaces. do. As a result, the LC composite chip component 110 is obtained.

The five inductors 122 to 126 are connected in series through the through holes 112a to 115a in the bare chip 141 to form an inductor, and the two grounding conductors 133 and 135 are provided. The capacitor overlaps with the inductor conductors 122, 124, and 126 via the sheets 112 to 115 to form a capacitor between these inductor conductors. This equivalent circuit is shown in FIG.

In addition, the composition of the magnetic ferrite powder shown in the above example may be one or two or more of Ni, Zn, Cu, Mn, Mg, Co and the like as an example. In addition, the composition of the dielectric ceramic powder is not limited to lead type, but may be a barium titanate type.

As described above, the composite magnetic material of the present invention is a composite magnetic material obtained by sintering a mixture of a dielectric material and a magnetic material, and there is almost no chemical reaction between the dielectric material and the magnetic material during sintering. It is easy to obtain a high-performance composite magnetic material containing no generated foreign matter.

According to the EMI filter of the present invention, the EMI filter is a mixed sintered body of the dielectric material and the magnetic material, and has almost no chemical reaction between the dielectric material and the magnetic material during sintering, and thus contains no foreign substances generated by the reaction. EMI filter with remarkable characteristics is provided with good reproducibility.

As stated above, according to the LC composite part and the LC composite chip part of the present invention, since the inductor and the capacitor are formed by using the green sheet made of the same ceramic material, the process is simplified and the thermal stress during firing is extremely small. It can be suppressed so that it can be prevented, troubles such as deformation and cracking in the bare chip can be avoided, and characteristic fluctuations are small.

In addition, since the grounding conductors are arranged in the same plane as the inductor conductors or vertically adjacent to the inductor conductors, the inductors formed by these inductor conductors have extremely low stray capacitance. Since a capacitor is formed between the conductor and each grounding conductor, it can be used to remove noise of a wide frequency.

Inductance and capacitance can also be increased or decreased by changing the current path of the inductor conductor in proportion to the number of stacked green sheets.

In particular, by using a material having not only a dielectric but also a magnetic material, sufficient inductance can be obtained, and a small noise filter capable of surface mounting on a printed circuit board or the like with high performance can be realized.

Claims (3)

The magnetic substance ferrite powder and the dielectric ceramic powder and the third material which lowers the sintering temperature and suppresses the chemical reaction between both powders at the time of sintering the magnetic ferrite powder and the mixture of the ceramic ceramic powder and the dielectric ceramic powder are mixed at a predetermined ratio. A plurality of green sheets 11 to 16 made of a composite ceramic material are formed by laminating a portion 12 to 16 so as to electrically insulate the inductor conductors 22 to 26 and the ground conductors 32 to 36 from each other. The bare chip 41 sintered using the laminate as a chip is mainly used. The inductor conductors 22 to 26 are spirally arranged in the thickness direction of the bare chip 41 through the through holes 12a to 15a formed of the sheets 12 to 15 inside the bare chip. The end 22a is exposed to the first end face of the bare chip 41, and the end 26a is connected to the second end face of the bare chip 41. Exposed, The grounding conductors 32 to 36 are adjacent to each other at intervals insulated from the inductor conductors 22 to 26 in the same plane as the inductor conductors 22 to 26 within the bare chip. And a capacitor formed between the inductor conductors 22 to 26 overlapping with the inductor conductors 22 to 26 via the sheets 12 to 15, and the one end 32a to the other. 36a) is exposed to the third and fourth cross-sections of the bare chip 41, First and second signal electrodes 42 and 43 electrically connected to the start end 22a and the end 26a of the inductor conductor exposed to the first and second end faces of the bare chip 41, respectively. It is installed on the first and second cross-sections, The first and second grounding electrodes 44 and 45 electrically connected to the ends 32a to 36a of the grounding conductor exposed to the third and fourth cross-sections of the bare chip 41 are described above. LC composite parts, characterized in that installed on the third and fourth end surface. The magnetic substance ferrite powder and the dielectric ceramic powder and the third material which lowers the sintering temperature and suppresses the chemical reaction between both powders at the time of sintering the magnetic ferrite powder and the mixture of the ceramic ceramic powder and the dielectric ceramic powder are mixed at a predetermined ratio. A plurality of green sheets 111 to 116 made of a composite ceramic material are formed by forming a plurality of green sheets 111 to 116 so as to electrically insulate the inductor conductors 122 to 126 and the grounding conductors 133 and 135 from each other. The bare chip 141 sintered using the laminate as a chip is mainly used. The inductor conductors 122 to 126 are cut surfaces in the thickness direction of the bare chips 141 through the through holes 112a to 115a formed of the sheets 112 to 115 in the bare chips 141. Is connected to the S-shape in series to form an inductor, the beginning end 122a of which is exposed to the first end surface of the bare chip 141, and the end 126a of the bare chip 141 described above. Is exposed to the second section of), The grounding conductors 133 and 135 overlap with the inductor conductors 122, 124, and 126 through the sheets 112 to 115 inside the bare chip. It is configured to form a capacitor between the inductor conductors 122 to 126, and both ends 133a, 133b, 135a, and 135b of the third and fourth portions of the bare chip 141 described above. Exposed in cross section, First and second signal electrodes 142 and 143 electrically connected to the start end 122a and the end 126a of the inductor conductor exposed to the first and second end faces of the bare chip 141, respectively. These first and second end faces are provided, First and second grounding electrodes electrically connected to both ends 133a, 133b, 135a, and 135b of the grounding conductor exposed to the third and fourth cross-sections of the bare chip 141. LC composite chip components, characterized in that (144) and (145) are provided on the third and fourth end surfaces. 3. The plurality of green sheets 111 to 116 according to claim 2, wherein the green sheets 111 to 116 made of a ceramic material composed only of the dielectric ceramic powder are replaced with a composite ceramic material in which the magnetic ferrite powder and the dielectric ceramic powder are mixed at a predetermined ratio. ), The inductor conductors 122 to 126 and the ground conductors 133 and 135 are formed to be electrically insulated from each other, and laminated. LC composite chip component, characterized in that.