JPH104329A - Noise filter array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the crosstalk noises which are caused by the capacitive coupling and inductive coupling of a dielectric substance of a high dielectric constant by using both dielectric substances of high and low dielectric constants to construct a dielectric substance and placing the dielectric substance of a high dielectric constant around the internal electrodes. SOLUTION: A dielectric substance 12 includes a dielectric substance 12a of a high dielectric constant and a dielectric substance 12b of a low dielectric constant which is buried into the substance 12a. Then the substance 12b of a plate shape is buried between the internal electrodes 11 by piercing through a lower surface 16 from an upper surface 15. The substance 12b does not touch the electrodes 11 and the substance 12a is placed near the electrodes 11. In such a constitution, the filter characteristic can be maintained owing to the substance 12a that is placed near the electrodes 11. At the same time, the crosstalk noises which are caused by the capacitive coupling and inductive coupling of the substance 12a can be decreased owing to the substance 12b that is placed between the electrodes 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a noise filter array, and more particularly to a noise filter array arrayed to reduce a mounting area.

[0002]

2. Description of the Related Art Filters are classified into a low-pass filter, a high-pass filter, a band-pass filter, a band-stop filter, and the like according to an operation band, and are usually constituted by an inductance (L) element and a capacitance (C) element. I have. These filters are also used for noise removal. Also, for the purpose of reducing the mounting area, a noise filter array in which filters are arrayed is often used.

FIG. 5 is a partially cutaway perspective view schematically showing an example of a conventional noise filter array.

The noise filter array 30 has a substantially rectangular parallelepiped shape, and a plurality of external electrodes 33 are formed on the front side surface 35 and the other side surface 36 of the noise filter array 30 in parallel in the vertical direction. The external electrodes 33 are formed in pairs at positions facing the side surface 35 on the near side and the side surface 36 on the other side. Further, an internal electrode 31 for connecting the external electrodes 33 facing each other is formed at an intermediate position in the height direction of the dielectric 32, and ground electrodes 34 are formed on the left and right side surfaces.

When the external electrode 33 and the ground electrode 34 are connected to a wiring pattern formed on the motherboard, and the noise filter array 30 having the above-described configuration is installed on the motherboard, it functions as a plurality of noise filters.

[0006]

In the noise filter array 30, the dielectric 3 interposed between the internal electrodes 31 is provided.
2 functions as a capacitor element portion, and the filter characteristic is improved as the dielectric constant is higher. For this reason, the dielectric 32 constituting the conventional noise filter array 30 has a high dielectric constant. As a result, the noise filter array 3
Although the filter characteristic of 0 is improved, there is a problem that as the used signal frequency increases, crosstalk noise generated due to capacitive coupling and inductive coupling in the dielectric 32 having a high dielectric constant increases. .

In order to cope with miniaturization of electronic equipment,
When the noise filter array 30 is downsized, the internal electrodes 3
Since the distance between the two is short, there is another problem that crosstalk noise generated due to capacitive coupling and inductive coupling is further increased.

As a noise filter for solving the above problem, a laminated electronic component in which a ground electrode is inserted between signal lines has been disclosed (JP-A-6-231995).
No.).

FIG. 6 is a perspective view schematically showing a multilayer feedthrough capacitor used as a noise filter or the like disclosed in the above publication.

A three-layered electrode is formed inside a rectangular parallelepiped dielectric 42, and a first grounding internal electrode 43 is formed on almost the entire upper and lower layers. In the middle layer, a first signal internal electrode 44 and a second signal internal electrode 45 are formed on the left and right sides, and a second ground internal electrode is provided at the center through a dielectric 42. 46 are formed. A ground external electrode 47a to which the first ground internal electrode 43 is connected is formed on the left and right side surfaces and in the vicinity thereof.
An external ground electrode 47b to which the first internal ground electrode 43 and the second internal ground electrode 46 are connected is formed in the vertical direction at the center of the surface 9 on the other side and on the other side. On both sides of this ground external electrode 47b, a first
The signal external electrode 48 to which the signal internal electrode 44 and the second signal internal electrode 45 are connected is formed.

In the multilayer feedthrough capacitor 40 having the above-described structure, even if the distance between the first signal internal electrode 44 and the second signal internal electrode 45 is reduced due to the size reduction, the first
A second ground internal electrode 46 formed between the signal internal electrode 44 and the second signal internal electrode 45,
The first internal electrode 43 for ground formed above and below the signal internal electrode 44 and the second signal internal electrode 45 of FIG.
It is described in the above-mentioned publication that there is an effect that it is possible to prevent the occurrence of crosstalk between the signal internal electrodes 44 and 45 and also to prevent the deterioration of characteristics.

However, when manufacturing a noise filter array based on the configuration shown in FIG. 6, a ground internal electrode is provided between the first signal internal electrode 44 and the second signal internal electrode 45 and above and below it. Since it is necessary to form the electrodes 43 and 46, there is a problem that the configuration of the electrodes becomes very complicated and the manufacturing cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is difficult to generate crosstalk noise even when the signal frequency is increased and the interval between signal electrodes is shortened. It is intended to provide an array.

[0014]

To achieve the above object, a noise filter array according to the present invention comprises:
In a noise filter array including a plurality of internal electrodes, a dielectric interposed between the internal electrodes, and external electrodes connected to the internal electrodes, the dielectric has a low dielectric constant dielectric and a high dielectric constant. It is characterized by comprising a dielectric constant dielectric, wherein the high dielectric constant dielectric is disposed around the internal electrode.

According to the noise filter array having the above-described structure, the characteristics as a filter can be maintained because the high dielectric constant dielectric is arranged near the internal electrode. In addition, since a low dielectric constant dielectric is interposed between the internal electrodes, crosstalk noise generated by capacitive coupling and inductive coupling of the high dielectric constant dielectric can be reduced.

Further, as compared with the conventional feedthrough capacitor shown in FIG. 6, the structure is simple and the capacitor can be manufactured relatively inexpensively.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a noise filter array according to the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view schematically showing a noise filter array according to an embodiment. The noise filter array 10 according to the embodiment has the same configuration as the noise filter array shown in FIG. 5 except for the portion of the dielectric 12, so that the configuration of the dielectric 12 will be mainly described here.

The dielectric 12 is a high dielectric constant dielectric 12a and the low dielectric constant dielectric 1 embedded in the high dielectric constant dielectric 12a.
2 b, and a plate-like low dielectric constant dielectric 12 b is buried between the plurality of internal electrodes 11 so as to penetrate from the upper surface 15 to the lower surface 16. Low dielectric constant dielectric 12b
Are not in contact with the internal electrodes 11, and have a structure in which a high dielectric constant dielectric 12a is arranged near the internal electrodes 11.

As a material for forming the high dielectric constant dielectric 12a, for example, (Sr _0.846 Ca _0.15 ) (Ti _0.992 Nb)
_0.008 ) SrTiO ₃ -based materials such as O ₃ , and the relative permittivity ε _r is preferably about 1 × 10 ^{3 to} 3 × 10 ⁵ . The material for forming the low k dielectric 12b, for example containing _{2MgO · 2Al 2 O 3 · SiO} 2 crystal M
Glass ceramics such as gO—Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ —R ₂ O (R is an alkali metal) glass and the like, and the relative permittivity ε _r thereof is preferably about 4-10.

For forming the internal electrode 11, for example, W, M
o, Pt, Mo—Mn and the like are used, and as the external electrode 13, Ag and the like are used in addition to the metal.

In this embodiment, the width D ₁ of the internal electrode 11 is 0.2 mm, and the distance D ₂ between the internal electrodes 11 is 0.8 m.
m, but the width D ₁ of the internal electrode 11 is preferably as small as possible.

Next, the noise filter array 1 having the above configuration
In the following, a method for manufacturing the high dielectric constant material 12a will be described as (Sr _0.846 C
a _0.15 ) (Ti _0.992 Nb _0.008 ) O ₃ was used as a material for forming the low dielectric constant dielectric 12b, and 2MgO · 2Al ₂ O ₃
· MgO-Al ₂ O ₃ -SiO containing SiO ₂ crystals
_{2 -B 2 O 3 -R 2 O} (R is an alkali metal) will be described using the glass ceramics such as glass.

First, the purity of the main component is 99.9%.
9% or more of SrCO ₃ , TiO ₂ , CaCO ₃ , Nb ₂
An O ₅ powder was prepared, weighed so as to have a desired composition ratio, put into a pot mill, and then SiO ₂ was used as a sintering aid.
And CuO, and about 0.01 mol% of SiO _{2 and} about 0.00025 mol% of CuO with respect to the main component.
And put into the pot mill. next,
After adding appropriate amounts of cobblestone, a dispersant, and pure water into the pot mill, wet mixing is performed for 24 hours, and the mixed slurry-like raw material is dehydrated and dried, and then crushed. Next, the crushed powder is transferred into a calcined crucible made of, for example, zirconia, and calcined. After the calcination synthesis, it is confirmed by X-ray analysis, composition analysis and the like that a solid solution having a predetermined composition has been synthesized.

Next, the crushed calcined synthetic powder was
The powder is sieved into uniform powder before and after, and a binder composed of a resin and a solvent is added to the sized powder to form a slurry. Next, a green sheet is formed by the doctor blade method using the slurry obtained in the above-described step. The thickness of the green sheet is preferably about 25 to 150 μm.

FIG. 2 is a perspective view schematically showing a part of the manufacturing process of the filter array 10 according to the embodiment.

As shown in FIG. 2, the lower green sheet 19a of the two green sheets 19a and 19b
A plurality of conductor paste layers 17a for the internal electrodes 11 are formed on the upper surface of the green sheet 19a so as to be parallel to the left and right sides. A plurality of conductive paste layers 17b for the external electrodes 13 are formed in parallel, and the conductive paste layers 17c for forming the ground electrodes 14 are formed on the left and right side surfaces.
Is formed and dried. Next, a rectangular through-hole 18 is formed between the conductive paste layers 17a for the internal electrodes 11 in a plan view. The through hole 18 is formed at a predetermined distance so as not to contact the conductive paste layer 17a for the internal electrode 11, and is formed such that the long side of the rectangle is parallel to the conductive paste layer 17a. Also, both ends of the through hole 18 are the green sheets 1.
If the green sheet 19a is too close to the front and rear sides of the green sheet 19a, the shape of the green sheet 19a is likely to collapse.
This through hole 18 is formed by a punch method as in the case of the through hole. On the front and rear side surfaces of the upper green sheet 19b, a plurality of conductor paste layers 17b for the external electrodes 13 are formed in the same position as the lower green sheet 19a in the vertical direction, and the left and right side surfaces are used for grounding. A conductive paste layer 17c for forming the electrode 14 is formed, and a through hole 18 is formed in the same manner as in the case of the green sheet 19a.

Thereafter, the two are laminated and pressure-bonded, and
After degreasing at about the temperature, 1380 ~
By baking at a temperature of 1550 ° C., a sintered body made into a semiconductor is manufactured. Next, after sufficiently washing this sintered body with an organic solvent or hot water, Bi ₂
A metal oxide paste containing O ₃ or CuO is applied and dried. Next, the sintered body coated with the metal oxide paste is fired in the air at a temperature of 1000 to 1350 ° C. to obtain a semiconductor ceramic composition in which grain boundaries are insulated.

The semiconductor ceramic composition has a through-hole 18 formed therein, and the through-hole 18 is filled with a slurry of a raw material powder for forming a glass ceramic. First, MgO-
As a raw material powder for producing Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ —R ₂ O (R is an alkali metal) glass,
0~30wt%, Al ₂ O ₃ is 5 to 20 wt%, SiO
₂ is 40 to 55 wt%, B ₂ O ₃ is 10 to 20 wt%,
After weighing each metal oxide so that the alkali metal is in the range of 0 to 5 wt% and putting it in a ball mill, 20 to 70 weight parts are used as aggregate powder with respect to 100 parts by weight of the glass composition powder. Parts of Al ₂ O ₃ powder, a binder composed of a resin and a solvent, and an appropriate amount of a plasticizer are added and wet-mixed to form a slurry. Next, the slurry is used to fill the through holes 18 by screen printing using a screen printing method. However, the screen printing may not be able to fill the entire inside of the through holes 18 with the screen printing method alone. After that, the slurry is pushed into the through hole 18 using a press machine or the like. If necessary, screen printing and pressing are performed several times. Thereafter, the sintered body filled with the slurry is
Low dielectric constant dielectric 1 by firing at 0 to 1000 ° C.
The layer 2b is formed, and the manufacture of the noise filter array 10 ends.

FIG. 3 is a partially cutaway perspective view schematically showing a noise filter array 20 according to another embodiment.

In this noise filter array 20, in order to increase the connection area between the internal electrode 11 and the motherboard, the side surface 25 on the front side and the side surface 26 on the other side are used.
A groove 22 extending from the upper surface to the lower surface is formed in a part of the portion where the external electrode 23 is formed.
3 is filled with metal. Also, wide grooves 22 are formed on the left and right side surfaces from the upper surface to the lower surface for the same purpose as described above, and the grooves 22 are filled with a metal constituting the ground electrode 24. In addition, the internal electrode 11, the low dielectric constant dielectric 12b, and the high dielectric constant dielectric 12a are configured in the same manner as in the case of the noise filter array 10 shown in FIG.

In the noise filter array 20, the connection with the wiring pattern formed on the motherboard can be performed more reliably.

[0032]

Examples and Comparative Examples Examples of the noise filter array according to the present invention will be described below. Also, a conventional noise filter array will be described as a comparative example. The manufacturing conditions and the like are described below.

<In the case of the embodiment> (1) Material constituting the noise filter array 10 Material for forming the high dielectric constant dielectric 12a (Sr _0.846 Ca _0.15 ) (Ti _0.992 Nb _0.008 ) O ₃
Mg containing formation consists composition semiconductor ceramic composition low k dielectric 12b material _{2MgO · 2Al 2 O 3 · SiO} 2 crystals
O-Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ —R ₂ O (R is an alkali metal) based glass Internal electrode 11, external electrode 13 and ground electrode 1
Material for forming 4: Number of platinum (Pt) internal electrodes 11: 6,
Number of external electrodes 13: 12 (6 pairs) (2) Production of green sheet 19 Production method of green sheet: doctor blade method Green sheet thickness: 50 μm (3) Firing of green sheet laminate Firing for semiconductor conversion Firing atmosphere Hydrogen: 10 vol%, nitrogen: 90 vol
% Firing temperature: 1450 ° C. grain boundary insulated firing the firing atmosphere for: atmospheric sintering temperature: 1150 ° C. (4) glass ceramic material powder filling and baking MgO-Al ₂ of the slurry into the through-hole 18 O ₃ -SiO ₂ -B ₂ O ₃ -R ₂ O
(R is an alkali metal) glass composition: MgO: 16 wt%, Al ₂ O ₃ : 20 wt%, SiO
₂ : 46 wt%, B ₂ O ₃ : 15 wt%, K ₂ O: 3 w
t% Weight ratio of glass composition powder to Al ₂ O ₃ powder Glass composition powder: 60 parts by weight, Al ₂ O ₃ powder: 40
Part by weight Firing Firing Firing atmosphere: In the air Firing temperature: 900 ° C. <Comparative Example> A green sheet 19 is prepared, and a conductive paste layer for the external electrode 33, the internal electrode 31, and the ground electrode 34 is formed and laminated. This was fired without forming the through-holes 18 to manufacture the noise filter array 30. In addition, baking for semiconductor conversion and baking for grain boundary insulation were performed in the same manner as in the example.

<Manufactured noise filter array 10,
Characteristics of 30> Dimensions of noise filter arrays 10 and 30 6 mm × 3 mm × 1.5 mm Width D ₁ of internal electrodes 11 and 31: 0.2 μm, distance D ₂ between internal electrodes 11 and 31: 0.8 μm Low dielectric constant Dimensions of dielectric 12b (in case of noise filter array 10) 500 μm × 2.4 mm × 1.5 mm Measurement of Crosstalk Noise For the manufactured noise filter arrays 10 and 30, the signal frequency and the crosstalk were measured using a network analyzer. Was measured.

FIG. 4 is a graph showing the relationship between signal frequency and crosstalk. As is clear from the graph shown in FIG. 4, in the case of the embodiment, since the low dielectric constant dielectric 12b is interposed between the internal electrodes 11, the crosstalk noise is lower than that of the comparative example. It has decreased significantly.
Although not shown in the graph, there was almost no difference in the filter characteristics between the example and the comparative example.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view schematically showing a noise filter array according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a part of a manufacturing process of the noise filter array according to the embodiment.

FIG. 3 is a partially cutaway perspective view schematically showing a noise filter array according to another embodiment.

FIG. 4 is a graph showing a relationship between a signal frequency and crosstalk in the noise filter arrays according to the example and the comparative example.

FIG. 5 is a partially cutaway perspective view schematically showing a conventional noise filter array.

FIG. 6 is a perspective view schematically showing a conventional feedthrough capacitor in which a grounding internal electrode is formed to prevent crosstalk noise.

[Explanation of symbols]

 10, 20 Noise filter array 11 Internal electrode 12 Dielectric 12a High dielectric constant dielectric 12b Low dielectric constant dielectric 13, 23 External electrode

Claims (1)

[Claims] 1. A noise filter array comprising a plurality of internal electrodes, a dielectric interposed between the internal electrodes, and external electrodes connected to the internal electrodes, wherein the dielectric has a low dielectric constant. A noise filter array comprising a dielectric constant and a high dielectric constant dielectric, wherein the high dielectric constant dielectric is disposed around the internal electrode.