JP2004153027A - Multiple capacitors - Google Patents

Abstract

A multiple capacitor capable of preventing poor adhesion between ceramic green sheets and reducing crosstalk noise between adjacent capacitor units is provided.
A laminate 1 formed by laminating a plurality of rectangular dielectric layers 2, a plurality of internal electrode layers 3 and 4 formed between the dielectric layers 2, an end face of the laminate 1, and In the multiple capacitor 10 including the plurality of external terminal electrodes 5 and 6 connected to the internal electrode layers 3 and 4, between adjacent internal electrode layers (3a-3b, 4a-4b), a ceramic paste is printed. It is characterized in that the formed dielectric filling layer 12 is interposed.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multiple capacitor, and more particularly to an internal structure.
[0002]
[Prior art]
With the spread of various electronic devices, the size and weight of electronic devices have been rapidly reduced. Accordingly, ceramic electronic components mounted on this electronic device have also been required to be miniaturized. In recent years, for example, multiple capacitors capable of miniaturization and large capacity have been widely used.
[0003]
By using such multiple type capacitors, it is possible to combine a plurality of single capacitors into one, reduce variations in the size and shape of each capacitor, and simplify the work of mounting on a circuit board, as compared to the past. Will be possible.
[0004]
A typical structure of a multiple capacitor is formed by stacking a plurality of rectangular dielectric layers, and external terminal electrodes are formed around a pair of end faces on the long side of the stack, for example. Have been. Then, for example, a plurality of internal electrode layers are arranged on the dielectric layer constituting the laminate 1. The internal electrode layers arranged on one dielectric layer extend from one end to the outside of the dielectric layer, that is, to the end face on the long side of the laminate, and are connected to, for example, external terminal electrodes. ing. Further, the internal electrode layers arranged on another dielectric layer extend from one end to the outside of the dielectric layer, that is, to the end face on the long side of the laminate, and are connected to, for example, external terminal electrodes. ing.
[0005]
FIG. 4 is a cross-sectional view of a conventional multiple capacitor, FIG. 4 (a) is a central cross-sectional view in the direction of the arrangement of the internal electrode layers of the laminate, and (b) a thickness direction showing the shape of the internal electrode layers. FIG.
[0006]
In the figure, 30 is a multiple capacitor, 31 is a laminate, 32 is a dielectric layer constituting the laminate 31, 33 and 34 are internal electrode layers formed in the laminate 31, and 35 and 36 are External terminal electrodes.
[0007]
As shown in the figure, the multilayer body 31 of the multiple capacitor 30 is formed by stacking a plurality of dielectric layers 32.
[0008]
In addition, for example, a plurality of internal electrode layers 33 and 34 are formed between the dielectric layers 32 of the laminate 31 to face each other. The internal electrode layer 33 is provided on one end surface of the laminate 31, and the internal electrode layer 34 is formed on the laminate 31. It extends to the other end face.
[0009]
Further, the plurality of external terminal electrodes 35 and 36 are attached to both end surfaces of the multilayer body 31 and are connected to the internal electrode layers 33 and 34, respectively.
[0010]
Then, the capacitor unit Na is formed by the dielectric layer 32, the internal electrode layers 33a, 34a, and the external terminal electrodes 35, 36 connected to the internal electrode layers 33a, 34a, and the dielectric layer 32, the internal electrode layers 33b, 34b and the internal External terminal electrodes 35 and 36 connected to the electrode layers 33b and 34b form a capacitor unit Nb.
[0011]
A method of manufacturing the multiple capacitor 30 will be described with reference to FIG. In addition, each code is not distinguished before and after firing.
[0012]
First, the ceramic green sheet 41 serving as the dielectric layer 32 has a plurality of element regions (denoted by reference numeral 32) defined by dotted lines. Thus, in the element region 32, internal electrode layer patterns 33 and 34 to be internal electrode layers are formed by screen printing of a conductive paste.
[0013]
Next, the ceramic green sheets 41 on which the internal electrode layer patterns 33 and 34 are printed are laminated and thermocompression-bonded in a predetermined order to obtain a large laminated body.
[0014]
Next, the large-sized laminate is cut along the boundary line (cutting line) C of the element region to obtain an unfired laminate in which the internal electrode layer patterns 33 and 34 are exposed on both end surfaces.
[0015]
Finally, the unfired laminate 31 is fired, and external terminal electrodes 35 and 36 are formed so as to be connected to the internal electrode layers 33 and 34 of the obtained laminate 31, respectively. A continuous capacitor 30 is obtained (Patent Document 1: Japanese Patent Application Laid-Open No. 2001-358034).
[Patent Document 1]
JP 2001-358034 A
[Problems to be solved by the invention]
However, according to the multiple capacitor 30, as shown in FIG. 5, when the distance between the internal electrode layer patterns 33 and 34 that can maintain insulation is m, the internal electrode layers on both sides of the cutting line C are provided. The distance between the patterns 33 and 34 is 2 × m, but the distance between the internal electrode layer patterns (33a-33b, 34a-34b) between adjacent capacitor units Na-Nb is m. Since the distance between the internal electrode layer patterns (33a-33b, 34a-34a) between the adjacent capacitor units Na-Nb is small, the upper and lower ceramic green sheets 41 do not adhere sufficiently during thermocompression bonding, and peeling occurs. And there is a problem that delamination easily occurs after firing.
[0017]
Further, when the thickness of the ceramic green sheet 41 is small, the step due to the presence or absence of the internal electrode layer patterns serving as the internal electrode layers 33 and 34 cannot be ignored. This moves inside the adjacent internal electrode layer patterns (33a-33b, 34a-34b), and the distance between adjacent internal electrode layers (33a-33b, 34a-34b) becomes small. As a result, there is a problem that crosstalk noise between adjacent capacitor units Na-Nb increases.
[0018]
The present invention has been devised in view of the above-described problems, and an object of the present invention is to provide a multiple capacitor capable of preventing poor adhesion between ceramic green sheets and reducing crosstalk noise between adjacent capacitor units. To provide.
[0019]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a laminated body formed by laminating a plurality of rectangular dielectric layers,
A plurality of the internal electrode layers are arranged between the dielectric layers, and one end thereof is exposed from an end face of the laminate,
A multiple capacitor formed on the end face of the laminate, and external terminal electrodes connected to the respective internal electrode layers,
A multiple capacitor is characterized in that a dielectric filler layer made of a material having a lower dielectric constant than the dielectric layer is interposed between the plurality of arranged internal electrode layers.
[Action]
According to the multiple capacitor of the present invention, the dielectric filling layer is disposed between the plurality of internal electrode layers arranged on the same dielectric layer (the same dielectric layer). Specifically, before and after the internal electrode layer pattern serving as the internal electrode layer is formed on the ceramic green sheet by printing with a conductive paste, the material is compared with the material of the ceramic green sheet in an adjacent region in the arrangement direction of the internal electrode layer pattern. Then, a paste serving as a dielectric filling layer is formed by printing using a dielectric ceramic paste made of a dielectric material having a low dielectric constant. As a result, even when the ceramic green sheet is thermocompression-bonded, the ceramic green sheet does not behave in an up-and-down manner, adheres sufficiently, suppresses peeling between the ceramic green sheets, and prevents delamination after firing. it can.
[0020]
Further, since there is no step between adjacent internal electrode layers due to the presence or absence of the internal electrode layer, the distance between adjacent internal electrode layers does not become small during thermocompression bonding, and crosstalk noise between adjacent capacitor units is reduced. be able to.
[0021]
In addition, since the dielectric filling element has a lower dielectric constant than the dielectric layer, the stray capacitance between adjacent internal electrode layers is reduced, so that crosstalk noise can be more effectively reduced.
[0022]
Further, the dielectric filling layer is formed so as to surround each side except the other end of the internal electrode layer. That is, even when the ceramic green sheets are stacked and pressed, the air remaining between the ceramic green sheets is easily degassed from the region where the dielectric filling layer does not exist. And the occurrence of cracks and delamination after firing can be suppressed, and the yield can be improved.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a multiple capacitor of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is an external perspective view of a multiple capacitor according to the present invention. 2A and 2B are cross-sectional views of the multiple capacitor of FIG. 1, in which FIG. 2A is a center cross-sectional view of the stacked body in a direction in which internal electrode layers are arranged, and FIG. FIG.
[0025]
In the figure, 10 is a multiple capacitor, 1 is a laminate, 2 is a dielectric layer constituting the laminate 1, 3 and 4 are internal electrode layers formed in the laminate 1, and 5 and 6 are External terminal electrodes.
[0026]
As shown in FIG. 2, the multilayer body 1 of the multiple capacitor 10 is formed by laminating a plurality of dielectric layers 2.
[0027]
The dielectric layer 2 is made of a non-reducing dielectric material containing barium titanate (BaTiO ₃ ) as a main component and a dielectric material containing a glass component, and has a shape of 2.0 mm × 1.2 mm or the like. The thickness is set to 1 to 5 μm to increase the capacity. The dielectric layer 2 is stacked in the upward direction in the drawing to form the laminate 1. The shape, thickness, and number of layers of the dielectric layer 2 can be arbitrarily changed according to the capacitance value.
[0028]
A plurality of internal electrode layers 3 (3a, 3b) are formed on the dielectric layer 2 (layers between the dielectric layers 2) of the laminate 1, and one end of the internal electrode layer 3 is connected to the extraction electrode layer 3z. , And extends to the outside of the dielectric layer 2 in the longitudinal direction, and is connected to the external terminal electrodes 5. Further, between the adjacent dielectric layers 2, the internal electrode layers 4 facing the plurality of internal electrode layers 3 are arranged. The internal electrode layer 4 is connected to an external terminal electrode 6 via a lead electrode layer (not shown). The internal electrode layers 3 and 4 are made of, for example, a material mainly containing Ni, and have a thickness of 1 to 2 μm.
[0029]
The external terminal electrodes 5 and 6 are formed on the pair of long side end surfaces of the multilayer body 1 and connected to the internal electrode layers 3 and 4, respectively. The external terminal electrodes 5 and 6 are made of, for example, a base metal component such as Cu, Ni, or an alloy thereof, and a glass component, and are formed on three surfaces, that is, an end surface on the long side and upper and lower surfaces adjacent thereto. Further, surface plating layers (not shown) are formed on the surfaces of the external terminal electrodes 5 and 6. The surface plating layer can be exemplified by, for example, Ni plating, Sn plating, solder plating, and the like. A characteristic of the present invention is that a plurality of internal electrode layers, for example, 3 arranged on one dielectric layer 2 have That is, the dielectric filling layer 12 is arranged in the adjacent regions. In the internal electrode layer 3a, a dielectric filling layer is formed on the short side end face side of the multilayer body 1 as well as the interval between the adjacent internal electrode layers 3b. Further, when the electrode width of the extraction electrode 3z is smaller than the electrode width of the internal electrode layer 3, the dielectric filling layer 12 is also formed on one end side of the internal electrode layer 3.
[0030]
As described above, in the internal electrode layer 3, the dielectric filling layers 12 are formed on three sides of the internal electrode layer 3 except for the other end side where the extraction electrode 3 z is not formed.
[0031]
The dielectric filling layer 12 is made of a material having a lower dielectric constant than the dielectric layer 2 and having a sintering behavior similar to that of the dielectric layer 2. Specifically, a dielectric multilayer ceramic material mainly containing SrTiO ₃ , CaTiO ₃ , and MgTiO ₃ can be exemplified.
[0032]
Next, a method for manufacturing the multiple capacitor 10 of the present invention will be described with reference to FIG.
[0033]
First, a ceramic green sheet mainly composed of, for example, BaTiO _{3 from} which a plurality of dielectric layers 2 can be extracted is prepared, and a conductive paste is printed on each element region of the ceramic green sheet by a screen printing method. An internal electrode layer pattern to be the electrode layer 3 or 4 and an electrode pattern to be the extraction electrode 3z are formed.
[0034]
This conductive paste is composed of a metal particle, an organic solvent composed of a mixture of an aliphatic hydrocarbon and a higher alcohol, an organic binder composed of ethyl cellulose soluble in the organic solvent, and a poorly soluble organic solvent. And an organic binder made of an epoxy resin.
[0035]
Next, a dielectric ceramic layer serving as the dielectric filling layer 12 is formed in a region between the plurality of internal electrode layer patterns arranged in each element region. The dielectric ceramic layer is formed by screen printing a ceramic paste so as to have substantially the same thickness as the internal electrode layer pattern. Note that the dielectric ceramic layer may be formed so as to surround other sides except for the other end of the internal electrode layer pattern.
[0036]
As the binder composition of the above-mentioned ceramic paste, both the same composition as the conductive paste or a different composition can be applied.In particular, the same conditions as in the printing of the conductive paste can be employed, and the binder of the binder from the surface of the ceramic green sheet can be used. It is desirable that the ceramic paste has the same binder composition as the conductor paste because the volatilization rates are matched.
[0037]
Then, the plurality of ceramic green sheets on which the respective electrode patterns serving as the internal electrode layer 3 (or 4) and the extraction electrode 3z (4Z are omitted in the figure) are formed are opposed to each other by the internal electrode layer patterns. Lamination is performed so that the electrode patterns serving as the extraction electrodes extend alternately to the pair of long side end surfaces of the laminate 1.
[0038]
Here, as a method of laminating the ceramic green sheets, after forming an internal electrode layer pattern and a dielectric ceramic layer on the main surface of the ceramic green sheet, a ceramic green sheet on which the internal electrode layer pattern and the dielectric ceramic layer are not formed is formed. By laminating the sheets and then sequentially forming the internal electrode layer pattern and the dielectric ceramic layer on the uppermost ceramic green sheet and sequentially laminating, the internal electrode layer is formed on the main surface of the flat ceramic green sheet. Since the layer pattern can be formed, the formation accuracy of the internal electrode layer pattern is improved, the capacitance variation can be reduced, and even if the number of stacked layers is increased, the formation accuracy of the internal electrode layer pattern is not affected. It is possible to realize a high lamination and a large size of the die capacitor 10.
[0039]
Further, a plurality of ceramic green sheets on which the respective electrode patterns serving as the internal electrode layer 3 (or 4) and the extraction electrode 3z (4Z are omitted in the drawing) are formed so that the internal electrode layer patterns face each other, Lamination is performed so that the electrode patterns serving as the extraction electrodes extend alternately to the pair of long side end surfaces of the laminate 1.
[0040]
Further, a ceramic green sheet on which an internal electrode layer pattern serving as the internal electrode layer 3, an electrode pattern serving as the lead electrode 3 z and a dielectric ceramic layer serving as the dielectric filling layer 12 are formed, and an internal electrode layer pattern serving as the internal electrode layer 4 Alternatively, a ceramic green sheet having an electrode pattern serving as a lead electrode and a dielectric ceramic layer serving as a dielectric filling layer 12 may be alternately laminated.
[0041]
Next, the laminated ceramic green sheets are thermocompression-bonded to form a large ceramic green sheet laminate.
[0042]
At this time, since the dielectric ceramic layer serving as the dielectric filling layer 12 is disposed between the adjacent internal electrode layer patterns, the upper and lower ceramic green sheets are sufficiently adhered to each other at the time of thermocompression bonding. Peeling can be suppressed, and the occurrence of delamination after firing can be prevented.
[0043]
In addition, since there is no step between adjacent internal electrode layer patterns due to the presence or absence of the internal electrode layer patterns, the distance between adjacent internal electrode layer patterns does not decrease during thermocompression bonding, and the cross between adjacent capacitor units does not occur. Talk noise can be reduced.
[0044]
Further, since the dielectric ceramic layer serving as the dielectric filling layer 12 is not formed at the other end of the internal electrode layer pattern (the end on the side where the extraction electrode is not formed), the above-described ceramic green sheet heat is not applied. At the time of press bonding, air remaining between the ceramic green sheets can be easily degassed, the adhesion between the internal electrode layer pattern and the ceramic green sheet is improved, and the occurrence of cracks and delamination after firing can be suppressed, The yield can be improved.
[0045]
Thereafter, the large ceramic green sheet laminate is cut at each desired position for each element region to obtain an unfired laminate. At this time, the extraction electrode of the internal electrode layer pattern is exposed on the long-side end surface of the laminate.
[0046]
Next, the laminate is baked by applying a predetermined atmosphere, temperature and time, and the external terminal electrode 5 connected to the internal electrode layer 3 of each capacitor unit is electrically connected to the external terminal electrode 6 connected to the internal electrode layer 4. It is formed by baking a paste. Thereafter, Ni plating / Sn plating is formed on the surface.
[0047]
Thus, the multiple capacitor 10 as shown in FIG. 1 is obtained.
[0048]
It should be noted that the present invention is not limited to the above embodiment, and various changes and improvements may be made without departing from the scope of the present invention.
[0049]
For example, in the above embodiment, the dielectric ceramic layer serving as the dielectric filling layer 12 may be formed also on the other end side of the internal electrode layers 3 and 4. That is, if the dielectric filling layer 12 is arranged between the parallel-arranged internal electrode layers 3 and 4 which are adjacent to each other in plane, crosstalk noise between them can be prevented. It may be formed on the entire surface of the region where each electrode layer is not formed so as to surround the layers 3 and 4 and the extraction electrode. At this time, it is important to sufficiently consider the lamination method so that air does not remain in the ceramic green sheets. Thus, a step due to the presence or absence of the internal electrode layers 3 and 4 can be completely eliminated.
[0050]
Further, the dielectric ceramic layer formed between the internal electrode layer patterns may be formed at a distance of 10 μm or more from the internal electrode layer pattern. In this way, even if a very large ceramic green sheet is used, a degassing path for thermocompression bonding of the ceramic green sheet can be secured. In addition, even when the peripheral region is stretched due to the printing pressure of the screen plate and the pattern of the internal electrode layer is displaced, the internal electrode layer pattern and the dielectric ceramic layer do not overlap. Deformation can be prevented.
[0051]
Further, the thickness of the dielectric ceramic layer serving as the dielectric filling layer 12 may be larger than the thickness of the internal electrode layer pattern serving as the internal electrode layers 3 and 4. Thus, the deformation of the internal electrode layer pattern by the lamination head that sucks the ceramic green sheet on which the internal electrode layer pattern and the dielectric ceramic layer are formed can be suppressed.
[0052]
Furthermore, when forming a large-sized laminate by applying pressure and heat, the ceramic green sheet is first subjected to pressure, and the internal electrode layer pattern is gradually subjected to pressure, so that short-circuit and insulation failure can be suppressed.
[0053]
Further, after the internal electrode layer pattern and the dielectric ceramic layer are formed on the main surface of the ceramic green sheet, another ceramic green sheet on which the internal electrode layer pattern and the dielectric ceramic layer are not formed is formed on the ceramic green sheet. May be laminated to form an internal electrode layer pattern and a dielectric ceramic layer on the ceramic green sheet, which may be sequentially repeated to produce a large laminate in an unfired state. As a result, the lamination accuracy is improved, the variation in capacitance can be reduced, and the side margin and end margin can be reduced, so that the multiple capacitor 10 can be downsized. Further, in the step of laminating the ceramic green sheets, another ceramic green sheet lined with a film is placed on the ceramic green sheet 2 on which the internal electrode layer pattern and the dielectric ceramic layer are formed, and the film is added from the film side. Pressure heating may be used. As a result, it is not necessary to provide a step of adsorbing the ceramic green sheets, so that defects of the ceramic green sheets 2 can be prevented.
[0054]
【The invention's effect】
According to the multiple capacitor of the present invention, since the ceramic layer formed by printing the ceramic paste is interposed between the adjacent internal electrode layers, the upper and lower ceramic green sheets adhere sufficiently during thermocompression bonding, The separation between the ceramic green sheets can be suppressed, and the occurrence of delamination after firing can be prevented.
[0055]
Further, since there is no step between adjacent internal electrode layers due to the presence or absence of the internal electrode layer, the distance between adjacent internal electrode layers does not decrease during thermocompression bonding, and crosstalk noise between adjacent capacitor units is reduced. be able to.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a multiple capacitor of the present invention.
FIGS. 2A and 2B are cross-sectional views of the multiple capacitor of FIG. 1, in which FIG. 2A is a central cross-sectional view in a width direction, and FIG. 2B is a plan cross-sectional view illustrating a planar shape of an internal electrode layer.
FIG. 3 is a plan view of a large ceramic sheet used in the method for manufacturing the multiple capacitor of FIG. 1;
FIGS. 4A and 4B are views showing a conventional multiple capacitor, in which FIG. 4A is a central cross-sectional view in the width direction, and FIG. 4B is a plan cross-sectional view showing a planar shape of an internal electrode layer.
FIG. 5 is a plan view of a large ceramic sheet used in the method for manufacturing the multiple capacitor of FIG. 4;
[Explanation of symbols]
10 Multiple capacitors 1 Multilayer 2 Dielectric layers 3, 4 Internal electrode layers 5, 6 External terminal electrodes 12 ... Dielectric filling layer N ... Capacitor unit 11 ... Large laminated body C ... ... Cutting line

Claims (1)

A laminate formed by laminating a plurality of rectangular dielectric layers,
A plurality of the internal electrode layers are arranged between the dielectric layers, and one end thereof is exposed from an end face of the laminate,
In the multiple capacitor formed on the end face of the laminate, and comprising a plurality of external terminal electrodes connected to the internal electrode layer,
A multi-layer capacitor, wherein a dielectric filling layer made of a material having a lower dielectric constant than the dielectric layer is disposed between the plurality of arranged internal electrode layers.

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