JPH07263279A - Lc composite component - Google Patents

Abstract

PURPOSE:To obtain an LC composite component in which a strain and a crack due to a firing operation are not generated, whose characteristic is changed little and which is excellent in the removal of a noise. CONSTITUTION:The starting end 22a and the termination end 26a of an inductor as well as ends 28c, 28d, on one side, of a conductor for a capacitor are exposed on both edges of a bare chip 41, and electrodes 42, 43 for signals are installed there. Ends 32a to 36a, 37a, 37b, 28a, 38b, on one side, of conductors for grounding are exposed on both of another edges of the bare chip, and electrodes 44, 45 for grounding are installed there. Conductors 22 to 26 for the inductor are constituted in such a way that they are connected in series spirally in the thickness direction of the bare chip via through holes 12a to 15a formed in sheets at the inside of the bare chip so as to form the inductor. Individual conductors 32 to 38 for grounding or conductors 28a, 28b for the capacitor are constituted in such a way that they are overlapped with the conductors for the inductor or with the conductor 37 for grounding via sheets 12 to 17 so as to form the capacitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LC composite component suitable for removing noise from electronic equipment. More specifically, the present invention relates to a chip-type LC composite component that has both a capacitor function and an inductor function that can be surface-mounted on a printed circuit board or the like.

[0002]

2. Description of the Related Art Conventionally, various LC composite parts having a monolithic structure by combining an inductor and a capacitor have been proposed. For example, the applicant of the present invention creates a capacitor laminate by alternately printing and laminating a dielectric ceramic layer and a capacitor conductor, and a magnetic ceramic layer and a ceramic layer on the capacitor laminate or separately. The inductor conductors are alternately printed and laminated to form an inductor laminate, and these capacitor laminates and inductor laminates are integrally sintered with the intermediate layer overlaid to expose the internal conductors. There is proposed an LC composite component in which an appropriate external terminal is provided at the end (for example, Japanese Patent Laid-Open No. 3-166810). In the inductor laminate of the LC composite component, the inductor conductor formed on the ceramic layer is connected layer by layer through the through holes provided in the ceramic layer to form a spiral shape in the thickness direction of the laminate. Is formed.

As another LC composite component, the applicant of the present invention has proposed a multilayer chip inductor having internal electrodes inside a ferrite sintered body and a multilayer chip capacitor having internal electrodes and a ground electrode inside a dielectric sintered body. A patent application was filed for a π-type LC filter in which the external electrodes of the multilayer chip inductor and the multilayer chip capacitor are electrically connected to each other by integrating them with an adhesive (Japanese Patent Application No. 5-112642).

[0004]

However, Japanese Patent Laid-Open No. 3-1 is used.
In the LC composite component disclosed in Japanese Patent No. 66810, since the thermal contraction rate of the capacitor laminate is different from the thermal contraction rate of the inductor laminate, thermal stress is generated from the difference in the thermal contraction rate during firing, and the intermediate layer is interposed. However, there were defects such as distortion, cracking, and characteristic fluctuations due to thermal stress, resulting in poor product yield and reliability. In addition, π-type L of Japanese Patent Application No. 5-112642
Although the C filter does not have the above-mentioned drawbacks, it requires that the multilayer chip inductor and the multilayer chip capacitor be separately sintered, which complicates the production control of the chip inductor and the chip capacitor and makes it difficult to reduce the product size. It was

It is an object of the present invention to provide an LC composite part which suppresses thermal stress to an extremely small value during firing and has less distortion, cracking and characteristic fluctuation. Another object of the present invention is to provide an LC composite component that has a small stray capacitance between windings of a coil pattern forming an inductor and is excellent in noise removal. Still another object of the present invention is to provide a small-sized and highly productive LC composite component that can be surface-mounted on a printed circuit board or the like.

[0006]

In order to achieve the above object, the structure of the present invention will be described with reference to FIG. 1 corresponding to an embodiment. The LC composite component 10 of the present invention includes a large number of green sheets 11 to 18 made of a composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio, and a part of the green sheets 11 to 18 is used for an inductor. After the conductors 22 to 26, the first grounding conductors 32 to 36, the second grounding conductor 37, the capacitor conductors 28a and 28b, and the third grounding conductor 38 are formed and laminated so as to be electrically insulated, The main body is a bare chip 41 obtained by forming the laminated body into chips and sintering the chips. Inductor conductors 22 to 26
Is configured to spirally connect in series in the thickness direction of the bare chip 41 via the through holes 12a to 15a formed in the sheets 12 to 15 inside the bare chip to form an inductor, and the starting end 22a thereof is the bare chip 41. First of
It is exposed on the end face and its end 26a is exposed on the second end face of the bare chip 41. The first grounding conductors 32 to 36 are adjacent to the inductor conductors 22 to 26 on the same plane as the inductor conductors 22 to 26 in the bare chip with a space therebetween so as to be insulated from the inductor conductors 22 to 26, and the inductors conductors are provided via the sheets 12 to 15. 22 to 26 is formed so as to form a capacitor between the inductor conductors 22 to 26, and one ends 32a to 36a thereof are exposed at the third and fourth end faces of the bare chip 41. The second grounding conductor 37 is formed on the sheet 17 circumscribing the uppermost or lowermost sheet 16 on which the inductor conductors 22 to 26 are formed, and the inductor conductors 22 to 26 and the first grounding conductor are interposed via the sheet 16. 32-
36, and both ends 37a, 3
7b is exposed on the third end surface and the fourth end surface of the bare chip 41. A pair of capacitor conductors 28a, 28b are formed at a distance from the sheet 18 circumscribing the sheet 17 on which the second grounding conductor 37 is formed, and are overlapped with the second grounding conductor 37 via the sheet 17 to form the second grounding line. A capacitor is formed between the conductor 37 and one end 28c, 28d of the capacitor is exposed on the first end face and the second end face of the bare chip 41. The third grounding conductor 38 is formed between the pair of capacitor conductors 28a, 28b of the sheet 18 on which the capacitor conductors 28a, 28b are formed with a space insulated from them, and both ends 38a, 38b are formed. The bare chip 41 is exposed at the third end surface and the fourth end surface. The first and second signal electrodes 42 and 43 electrically connected to the starting end 22a and the terminating end 26a of the inductor conductor and both ends 28c and 28d of the capacitor conductor exposed on the first and second end surfaces of the bare chip 41 are respectively provided. First and second
One end 32a of the first, second and third grounding conductors provided on the end face and exposed on the third and fourth end faces of the bare chip 41.
To 36a and both ends 37a, 37b, 38a, 38b, first and second grounding electrodes 44, 45 are provided on the third and fourth end faces.

In the above-mentioned LC composite component, a large number of green sheets made of a ceramic material consisting only of dielectric ceramic powder are used in place of the composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio. The sheets 11 to 18 are partially covered with the conductors 12 to 18, the inductor conductors 22 to 26, the first ground conductors 32 to 36, the second ground conductor 37, and the capacitor conductors 28a and 28b.
Alternatively, the bare chip 41 may be the main body, which is formed by electrically insulating the third grounding conductor 38 and the third grounding conductor 38, and stacking them, and then stacking the stacked body into a chip shape.

[0008]

Since the inductor and the capacitor are formed by using the green sheets 12 to 18 made of the same ceramic material, the process can be simplified, and the thermal stress at the time of firing can be suppressed to a very small level, and the bare chip can be used. 41 can avoid problems such as distortion and cracks. Further, they are adjacent to the inductor conductors 22 to 26 on the same plane, or vertically adjacent to the inductor conductors 22 to 26, respectively, and the first ground conductors 32 to 36, the second ground conductor 37, and the third ground conductor. Since the conductors 38 and the capacitor conductors 28 are arranged, the inductors formed by the inductor conductors 22 to 26 generate very little stray capacitance, and furthermore, the inductor conductors 22 to 26 and the grounding conductors 32 to 38, respectively. Since a plurality of capacitors are formed between the capacitor and the conductor 28 for a capacitor, the circuit configuration is such that a T-type circuit and a π-type circuit are combined, as shown in FIG. 4, and can be used for removing noise in a wide range of frequencies. .

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the LC composite component of this embodiment, a large number of green sheets starting from a composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio are laminated, and this laminated body is formed into chips and baked. Made by tying. This composite ceramic material is a composite functional material having both constant magnetic permeability and constant dielectric constant. In this example, NiO, ZnO, CuO and Fe are used as the magnetic ferrite powder.
Each powder of ₂ O ₃ was weighed so as to have a predetermined ratio and then wet mixed. After firing the mixture at 1000 ° C. for 2 hours,
Wet milling was carried out to prepare magnetic ferrite powder having an average particle size of about 0.1 μm. This composition is Ni _0.24 Zn _0.22 Cu
_{It was 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 so as to have a predetermined ratio and then wet mixed. The mixture was baked at 1150 ° C. for 2 hours and then wet-milled to prepare a dielectric ceramic powder having an average particle size of about 0.1 μm. This composition is Pb _0.88 La _0.12 Zr _0.7 Ti _0.3 O
It was _3.06 .

By mixing the prepared magnetic ferrite powder and dielectric ceramic powder in a weight ratio of 60:40, a composite ceramic material having a sintering temperature of about 1030 ° C. can be obtained. The mixing ratio of the magnetic ferrite powder and the dielectric ceramic powder is preferably selected from the range of 60-40: 40-60. Further, in order to suppress the reaction between the materials of the magnetic ferrite powder and the dielectric ceramic powder during firing and to lower the firing temperature, it is preferable to add an improving material. This improving material is, for example, CdO-ZnO as a composition system.
A _{-B 2 O 3, CdO, ZnO} , B 2 O 3 to 1: 1: 1
After being mixed at a molar ratio of 1, the powder is obtained by firing at 900 ° C. for 1 hour and milling, and having an average particle size of about 0.1 μm. In this example, the magnetic ferrite powder, the dielectric ceramic powder and the improving 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 mill-mixed with a binder and a binder solvent that can be gasified during firing to prepare a slurry, and this slurry is formed into a green sheet by a doctor blade method. The sheet can be prepared by kneading the composite ceramic material, the binder, and the solvent for the binder to form a paste, and printing the paste.

A large number of green sheets thus obtained are laminated. A conductive paste is applied to the surface of some of the green sheets by a screen printing method so that the inductor conductor and the ground conductor are electrically insulated from each other. Through holes are formed at the interconnection positions of the inductor conductors of the green sheet, and a predetermined number of layers are stacked while filling the through holes with a conductive paste if necessary. The obtained laminate is pressure-molded, cut into chips, and fired to form bare chips.

As shown in FIG. 1A, an example in which eight green sheets 11 to 18 are laminated is given here for the sake of simplicity. 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 first grounding conductors 32 to 36 are formed with a space therebetween so as to be electrically insulated. A second earth conductor 37 is formed on the seventh green sheet 17, and a pair of capacitor conductors 28 is formed on the eighth green sheet 18.
The a and 28b and the third grounding conductor 38 are formed at a distance such that they are electrically insulated.

Second to fifth green sheets 12 to 1
Through holes 12a-1 for connecting to the inductor conductors of the lower layer are formed at the ends of the inductor conductors 22-25 of FIG.
5a is opened, and when the five inductor conductors 22 to 26 are stacked, 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 starting end of the inductor. One end 26a of the inductor conductor 26 of the sixth green sheet 16 extends to another end edge of the green sheet 16 as the end of the inductor. First earth conductor 3
2 to 36 are adjacent to the inductor conductors 22 to 26, and one ends 32a to 36a thereof extend alternately to the side edges of the green sheets 12 to 16, respectively.

The second grounding conductor 37 formed on the seventh green sheet 17 is constructed so as to overlap the inductor conductors 22 to 26 and the first grounding conductors 32 to 36, and one end 37a and the other end 37b thereof are formed. Extend to two opposite side edges. The pair of capacitor conductors 28a and 28b formed on the eighth green sheet 18 are spaced from each other, and the third grounding conductor 38 is formed between them. One end 38a and the other end 38b of the third grounding conductor extend to two opposite side edges of the green sheet 18.

When these green sheets 11 to 18 are laminated and fired, a rectangular parallelepiped sintered bare chip 41 is obtained. As shown in FIG. 1B, FIG. 2 and FIG. 3, one end 22 a of the inductor conductor 22 and the capacitor conductor 2 which is the starting end of the inductor are formed on the first end surface of the bare chip 41.
One end 2c of the inductor conductor 26, which is exposed at one end 28c of 8a and serves as the end of the inductor (not shown) on the second end face.
6a and one end 28d of the capacitor conductor 28b are exposed. Similarly, the bare chip 41 has a first end on the third and fourth end faces.
One ends 32a to 36a of the grounding conductors 32 to 36 and one ends 37a and 38a and the other ends 37b and 38b of the second and third grounding conductors 37 and 38 are exposed alternately. First and second
Signal electrodes 42 and 43 are formed by applying a conductive paste to the end faces and baking, and ground electrodes 44 and 45 are similarly formed on the third and fourth end faces. Thereby, the LC composite component 10 is obtained. The five inductor conductors 22 to 26 are connected in series inside the bare chip 41 through the through holes 12a to 15a to form an inductor, and the five first ground conductors 32 to 36 and the second and third ground conductors are formed. 37, 38 and capacitor conductor 28
The sheets a and 28b overlap with the inductor conductors 22 to 26 via the sheets 12 to 17 to form a capacitor with these inductor conductors. This equivalent circuit is shown in FIG.

The composition of the magnetic ferrite powder shown in the above example is an example, and Ni, Zn, Cu, Mn, M
One or two or more of g, Co, etc. may be contained. The composition of the dielectric ceramic powder is not limited to the lead-based composition, but may be the barium titanate-based composition.

[0017]

As described above, according to the present invention, since the inductor and the capacitor are formed by using the green sheets made of the same ceramic material, the process can be simplified and the firing Thermal stress can be suppressed to an extremely low level, problems such as distortion and cracks in bare chips can be avoided, and characteristic fluctuations are small. Since the grounding conductor and the capacitor conductor are arranged adjacent to each other on the same plane as the inductor conductor or vertically adjacent to the inductor conductor, the inductor formed by these inductor conductors is The generation is extremely small, and since a plurality of capacitors are formed between the inductor conductor and each of the grounding conductor and the capacitor conductor, the circuit configuration is such that a T-type circuit and a π-type circuit are combined, and a wide range of frequencies is obtained. It can be used for noise removal. In particular, by using a material that has the characteristics of a magnetic substance as well as a dielectric substance, sufficient inductance can be obtained,
It is possible to realize a small noise filter which has high performance and can be surface-mounted on a printed circuit board or the like.

[Brief description of drawings]

FIG. 1A is a perspective view of a green sheet of an LC composite component of the present invention before being laminated. (B) is a perspective view of the LC composite component.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is an equivalent circuit diagram thereof.

[Explanation of symbols]

 10 LC composite parts 11-18 Green sheet 12a-15a Through hole 22-26 Inductor conductor 22a Inductor start end 26a Inductor end 28a, 28b Capacitor conductor 28c, 28d One end of capacitor conductor 32-36 First earth conductor 32a to 36a One end of first grounding conductor 37 Second grounding conductor 37a One end of second grounding conductor 37b Other end of second grounding conductor 38 Third grounding conductor 41 Bare chip 42,43 Signal electrode 44,45 Ground electrode

Claims (2)

[Claims] 1. A large number of green sheets (11 to 18) made of a composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed in a predetermined ratio, and a part (12) of them.
~ 18) and inductor conductors (22-26) and first ground conductor
(32 to 36), second earth conductor (37) and capacitor conductor (2
8a, 28b) and the third grounding conductor (38) are formed so as to be electrically insulated and laminated, and then the laminated body is mainly formed of a bare chip (41) which is sintered, The inductor conductors (22 to 26) are through holes (12a to 15) formed in the sheet (12 to 15) inside the bare chip.
It is configured to spirally connect in series in the thickness direction of the bare chip (41) via a) to form an inductor, and its starting end (22a) is exposed at the first end surface of the bare chip (41), And the end (26a) thereof is exposed at the second end surface of the bare chip (41), and the first grounding conductors (32 to 36) are in the same plane as the inductor conductors (22 to 26) inside the bare chip. The inductor conductors (22 to 26) are adjacent to each other with a space insulated from each other, and the inductor conductors are provided via the sheets (12 to 15).
(22-26) so as to form a capacitor between the inductor conductors (22-26) and one end (32a-36a) of the bare chip (41) of the third and fourth. The second grounding conductor (37) is exposed at the end face, and the second grounding conductor (37) is the inductor conductor (22).
To 26) are formed on a sheet (17) circumscribing the uppermost or lowermost sheet (16) formed, and the inductor conductors (22 to 26) and the first ground are formed through the sheet (16). Conductor (3
2-36), and both ends (37a, 37a)
b) is exposed on the third end surface and the fourth end surface of the bare chip (41), and the capacitor conductors (28a, 28b) are circumscribed on the sheet (17) having the second grounding conductor (37) formed thereon. A pair of sheets (18) are formed at intervals, and overlap with the second grounding conductor (37) through the sheet (17) to form a capacitor between the second grounding conductor (37). Is configured as
And one end (28c, 28d) thereof is exposed to the first end surface and the second end surface of the bare chip (41), and the third grounding conductor (38) is the capacitor conductor (28
a, 28b) is formed between the pair of capacitor conductors (28a, 28b) of the sheet (18) on which they are formed with a space therebetween, and both ends (38a, 38b) are the bare chips.
The starting end (22a) and the terminating end (26a) of the inductor conductor and the both ends of the capacitor conductor (26a) exposed on the third end face and the fourth end face of (41) and exposed on the first and second end faces of the bare chip (41). 28c, 28d) first and second signal electrodes (42, 43) electrically connected to the first and second end faces, respectively, and exposed at the third and fourth end faces of the bare chip (41). First and second electrically connected to one end (32a to 36a) and both ends (37a, 37b, 38a, 38b) of the first, second and third grounding conductors.
An LC composite component, wherein ground electrodes (44, 45) are provided on the third and fourth end faces. 2. The LC composite component according to claim 1, wherein
Part of a large number of green sheets (11-18) made of a ceramic material consisting only of dielectric ceramic powder instead of the composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio ( 12-18), inductor conductors (22-26), first earth conductors (32-36) and second
Ground conductor (37), capacitor conductor (28a, 28b) and third
An LC composite component comprising a bare chip (41) as a main body, which is formed by electrically insulating the grounding conductor (38) and laminating the laminated body, and then laminating the laminated body into a chip.