JPH07263281A - Chip-shaped 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 23a and the termination end 25a of an inductor as well as ends 22c, 22d, 26c, 26d, on one side, of conductors for a capacitor are exposed, and electrodes 42, 43 for signals are installed there. Ends 33a to 35a, 32a, 32b, 36a, 36b, 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 23 to 25 for the inductor are connected spirally in the thickness direction of the bare chip via through holes 13a, 14a formed in sheets at the inside of the bare chip, and the inductor is formed. Individual conductors 32 to 36 for grounding or conductors 22a, 22b, 26a, 26b for the capacitor are constituted in such a way that they are overlapped with the conductors for the inductor via sheets 12 to 15 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 a chip type 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

An object of the present invention is to provide a chip-type LC composite component 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 reduce the stray capacitance between the windings of the coil pattern that forms the inductor, and to reduce the noise of a chip type L that is excellent in noise removal.
To provide C composite parts. It is still another object of the present invention to provide a chip-type LC composite component which can be surface-mounted on a printed circuit board or the like and is small in size and high in productivity.

[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 chip-type LC composite component 10 of the present invention includes a large number 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. Inductor conductors 23 to 25, first ground conductors 33 to 35, second ground conductors 32 and 36, and capacitor conductor 22.
The bare chip 41 is mainly formed by forming and laminating the a, 22b, 26a, and 26b so as to electrically insulate the laminated body, and then laminating the laminated body into a chip shape. The inductor conductors 23 to 25 are formed on the sheets 13 and 14 inside the bare chip.
It is configured so as to form an inductor by spirally connecting in series in the thickness direction of the bare chip 41 via the through holes 13a and 14a formed in, and the starting end 23a is exposed at the first end surface of the bare chip 41, Moreover, the end 25a thereof is exposed on the second end surface of the bare chip 41. The first grounding conductors 33 to 35 are arranged inside the bare chip to form the inductor conductor 23.
Between the inductor conductors 23 to 25 and the inductor conductors 23 to 25 in the same plane as the inductor conductors 23 to 25 with an interval therebetween so as to be insulated from the inductor conductors 23 to 25. It is configured to form a capacitor, and one end 33a to 35a of the bare chip 41 is formed.
Is exposed at the third and fourth end faces of. Capacitor conductor 22
a, 22b, 26a and 26b are inductor conductors 23 to
A pair of sheets 12 and 16 circumscribing the uppermost sheet and the lowermost sheet formed with 25 are formed with a space therebetween, and the sheet 1
The first grounding conductors 33 and 35 are overlapped with the second grounding conductors 2 and 15 to form a capacitor between the first grounding conductors 33 and 35, and one ends 22c and 22d thereof are formed.
26c and 26d are exposed on the first end surface and the second end surface of the bare chip 41. The second ground conductors 32 and 36 are the pair of capacitor conductors 22a, 2 of the sheets 12, 16 on which the capacitor conductors 22a, 22b, 26a, 26b are formed.
2b, 26a, and 26b are formed at a distance so as to be insulated from them, and are overlapped with the inductor conductors 23 and 25 via the sheets 12 and 15, and the inductor conductors 23 and 2 are overlapped.
5 to form a capacitor, and both ends 32a, 32b, 36a, 36b thereof are exposed at the third end face and the fourth end face of the bare chip 41. Bare chip 4
The first and second signal electrodes 42 electrically connected to the starting end 23a and the terminating end 25a of the inductor conductor and the ends 22c, 22d, 26c, and 26d of the capacitor conductor, respectively, which are exposed on the first and second end faces of 1. 43 is provided on the first and second end faces. One ends 33a of the first and second grounding conductors exposed on the third and fourth end faces of the bare chip 41,
34a, 35a and both ends 32a, 32b, 36a, 36
First and second grounding electrodes 44, 4 electrically connected to b
5 are provided on the third and fourth end faces.

In the above-mentioned chip-type LC composite component, a large number of ceramic materials made of only 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. Part of the green sheets 11-16 is 12-16
Inductor conductors 23 to 25 and first ground conductor 33
˜35, the second grounding conductors 32 and 36, and the capacitor conductors 22a, 22b, 26a, and 26b are formed so as to be electrically insulated and laminated, and then the laminated body is sintered into chips. The bare chip 41 may be the main component.

[0008]

Since the inductor and the capacitor are formed by using the green sheets 12 to 16 made of the same ceramic material, the process can be simplified, and the thermal stress at the time of firing can be suppressed to an extremely 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 23 to 25 in the same plane, or vertically adjacent to the inductor conductors 23 to 25, respectively, and the first grounding conductors 33 to 35, the second grounding conductors 32 and 36, and the capacitors. Since the conductors 22a, 22b, 26a, and 26b are arranged, the inductor formed by these inductor conductors 23 to 25 has very little generation of stray capacitance, and moreover, the inductor conductors 23 to 25 and the respective ground conductors 32 to 25. 36 and the capacitor conductor 22a,
Since a plurality of capacitors are formed between the capacitors 22b, 26a, and 26b, the circuit configuration is such that a T-type circuit and a π-type circuit are combined as shown in FIG. 4, and it can be used for noise removal in a wide range of frequencies. .

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. The chip-type LC composite component of the present embodiment is obtained by stacking 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, and stacking the stacked body into a chip shape. It is made by sintering. This composite ceramic material is a composite functional material having both constant magnetic permeability and constant dielectric constant. In this example, NiO, ZnO, Cu is used as the magnetic ferrite powder.
Each powder of O and Fe ₂ O ₃ was weighed so as to have a predetermined ratio, and then wet mixed. The mixture was fired at 1000 ° C. for 2 hours and then wet-milled to prepare magnetic ferrite powder having an average particle size of about 0.1 μm. This composition is Ni _0.24 Z
It was n _0.22 Cu _0.06 Fe _0.96 O _1.96 . Further, as dielectric ceramic powder, PbO, La ₂ O ₃ , ZrO ₂ , TiO ₂
The respective powders of 1 were 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
It was Ti _0.3 O _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 six green sheets 11 to 16 are laminated is given here for the sake of simplicity of description. Nothing is printed on the first green sheet 11 and no conductor is formed. On the surfaces of the third to fifth green sheets 13 to 15, the inductor conductors 23 to 25 and the first grounding conductors 33 to 35 are formed with a space therebetween so as to be electrically insulated. On the second and sixth green sheets 12 and 16, a pair of capacitor conductors 22a, 22b and 26a, 26b and second grounding conductors 32 and 36 are formed with a space therebetween so as to be electrically insulated. It

The third and fourth green sheets 13,
At the ends of the inductor conductors 23 and 24 of FIG.
14a is opened and three inductor conductors 23 to 25 are formed.
When they are stacked, they are connected in series in a spiral shape in the thickness direction to form an inductor. One end 23a of the inductor conductor 23 of the third green sheet 13
Extends to the edge of the green sheet 13 as the starting end of the inductor. One end 25a of the inductor conductor 25 of the fifth green sheet 15 extends to another end edge of the green sheet 15 as the end of the inductor. The first grounding conductors 33 to 35 are adjacent to the inductor conductors 23 to 25, and one ends 33a to 35a thereof are respectively green sheets 13 to 15.
Alternate on the side edges of

A pair of capacitor conductors 2 formed on the second and sixth green sheets 12 and 16, respectively.
Second grounding conductors 32 and 36 are formed between 2a, 22b and 26a, 26b, respectively. The one ends 32a, 36a and the other ends 32b, 36b of the second ground conductors extend to the two opposite side edges of the green sheets 12, 16 and the inductor conductors 23, 25 adjacent to each other with the green sheets 12, 15 separated. Overlapping overlapping parts 32c and 36
have c.

When these green sheets 11 to 16 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 23 a of the inductor conductor 23, which is the starting end of the inductor, and the capacitor conductor 2 are formed on the first end surface of the bare chip 41.
Although one ends 22c and 26c of the conductors 2a and 26a are exposed, one end 25a of the inductor conductor 25 and the capacitor conductors 22b and 26, which are not shown in the drawing, serve as a termination of the inductor on the second end face.
One ends 22d and 26d of b are exposed. Similarly, on the third and fourth end faces of the bare chip 41, the first grounding conductors 33 to 3 are formed.
5, one end 33a to 35a is exposed alternately, one end 32a, 36a and the other end 32b of the second grounding conductor 32, 36,
36b are exposed to each other. Signal electrodes 42 and 43 are formed by applying and baking a conductive paste on the first and second end faces, and ground electrodes 44 and 45 are similarly formed on the third and fourth end faces. Thereby, the LC composite component 10 is obtained. Three inductor conductors 23-2
Reference numeral 5 indicates the through holes 13a, 14 inside the bare chip 41.
a is connected in series to form an inductor, and three first grounding conductors 33 to 35 and a second grounding conductor 32,
36 and conductors 22a, 22b, 26a, 2 for capacitors
6b is a conductor for inductor 23 through the sheets 12 to 15
~ 25 to form a capacitor between 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, it can be used for noise removal in a wide range of frequencies. 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 has a circuit structure that combines a T-type circuit and a π-type circuit,
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 before lamination of a chip-type LC composite component of the present invention. (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 11-16 Green sheet 13a, 14a Through hole 23-25 Inductor conductor 23a Inductor start end 25a Inductor end 22a, 22b, 26a, 26b Capacitor conductor 22c, 22d, 26c, 26d One end of capacitor conductor 33 to 35 First ground conductor 33a to 35a One end of first ground conductor 32,36 Second ground conductor 32a, 36a One end of second ground conductor 32b, 36b Other end of second ground conductor 41 Bare chip 42 , 43 Signal electrodes 44, 45 Ground electrodes

Claims (2)

[Claims] 1. A large number 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 partially used (12).
To 16) and inductor conductors (23 to 25) and first earth conductor
(33 to 35), the second grounding conductors (32, 36) and the capacitor conductors (22a, 22b, 26a, 26b) are formed so as to be electrically insulated and laminated, and then the laminated body is chipped. Mainly a bare chip (41) that has been sintered into a shape, the inductor conductors (23 to 25) are through holes (13a, 14a) formed in the sheet (13, 14) inside the bare chip.
Via a series of spirally connected in the thickness direction of the bare chip (41) to form an inductor.
(23a) is exposed at the first end surface of the bare chip (41), and its end (25a) is exposed at the second end surface of the bare chip (41), and the first grounding conductors (33-35) are Inside the bare chip, adjacent to the inductor conductors (23 to 25) in the same plane as the inductor conductors (23 to 25) with a gap being insulated from the inductor conductors (23, 25), and for the inductors via the sheets (13, 14). conductor
(23-25) so as to form a capacitor between the inductor conductors (23-25) and one end (33a-35a) of the third and fourth bare chips (41). Exposed on the end face, the capacitor conductors (22a, 22b, 26a, 26b) are spaced on the sheets (12, 16) circumscribing the uppermost and lowermost sheets on which the inductor conductors (23 to 25) are formed. The first grounding conductor is formed in a pair by opening the sheet (12, 15).
(33, 35) is overlapped with (33, 35) to form a capacitor between the first grounding conductor (33, 35), and one end thereof is formed.
(22c, 22d, 26c, 26d) are exposed on the first end surface and the second end surface of the bare chip (41), and the second grounding conductor (32, 36) is the capacitor conductor.
(22a, 22b, 26a, 26b) formed sheet (12, 16) between the pair of capacitor conductors (22a, 22b, 26a, 26b) of the pair are formed with an interval insulated from them, The seat (12,1
5) via the inductor conductor (23, 25) to overlap to form a capacitor between the inductor conductor (23, 25), and both ends (32a, 32b, 36a, 36b )
Are exposed at the third end surface and the fourth end surface of the bare chip (41), and the start end (23a) and end (25a) of the inductor conductor and the capacitor conductor exposed at the first and second end surfaces of the bare chip (41). First and second signal electrodes (42, 43) electrically connected to one end (22c, 22d, 26c, 26d) of the bare chip (41) are provided on the first and second end faces, respectively. The first exposed on the third and fourth end faces
And one end (33a, 34a, 35a) and both ends (32
a, 32b, 36a, 36b) first and second grounding electrodes (44, 45) electrically connected to the third and fourth end faces are provided on the chip type LC composite component. . 2. The chip-type LC composite component according to claim 1, wherein the composite ceramic material in which magnetic ferrite powder and dielectric ceramic powder are mixed at a predetermined ratio is replaced with a ceramic material consisting of only dielectric ceramic powder. A large number of green sheets (11 to 16) made in part (12 to 1)
6) Inductor conductors (23-25) and 1st earth conductor (33
~ 35), the second ground conductor (32, 36) and the capacitor conductor (2
2a, 22b, 26a, 26b) are formed so as to be electrically insulated from each other and stacked, and then the chip-shaped LC composite component mainly composed of a bare chip (41) obtained by sintering the stacked body into a chip shape. .