JP5324246B2 - Multilayer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer capacitor having high mechanical characteristics. <P>SOLUTION: The multilayer capacitor 100 having one face 100a and an opposing face 100b includes: a plurality of dielectric layers 110 formed between one face 100a and the opposing face 100b; a plurality of internal electrode layers 120 laminated via the dielectric layers; a via electrode 140 for electrically connecting the internal electrode layers; and an external electrode layer 150 arranged on one face and/or the opposing face while being electrically connected to the via electrode. The internal electrode layer 120, the via electrode 140, and the external electrode layer 150 include metal nickel as a main constituent; the dielectric layer 110 includes barium titanate as a main constituent; and a dielectric layer for composing respective surface layer sections 110a, 110b at one face side and at the opposing face side includes metal nickel. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a multilayer capacitor. More specifically, the present invention relates to a multilayer capacitor having a structure in which a plurality of ceramic dielectric layers and a plurality of internal electrode layers are alternately stacked.

Conventionally, a via array type multilayer capacitor having a structure in which a plurality of ceramic layers and a plurality of internal electrode layers are alternately stacked is known and used for decoupling applications. Barium titanate (BaTiO ₃ ) is frequently used for the ceramic layer of the via array type multilayer capacitor for decoupling because it can be increased in capacity. However, although barium titanate is excellent in dielectric properties, it has poor mechanical properties, so that high strength is required.

JP-A-5-1117016 JP-A-5-279117 JP-A-6-096987 JP-A-9-148175

Although the said patent documents 1-4 are known with respect to the said problem, more excellent mechanical strength and another method are calculated | required.
In particular, in recent years, the usage environment of multilayer capacitors has become increasingly severe, and in particular, the amount of heat generated by the MPU has increased, and the MPU wiring board and the decoupling capacitor mounted thereon have a sudden temperature difference. Exposed to heating and rapid cooling. In addition, due to recent demands for low profile and narrow space, it is required to incorporate electronic components (capacitors, etc.) in the MPU wiring board. The built-in electronic components are resins that constitute the wiring board. A large stress due to a difference in thermal expansion with the material is placed in an environment in which it is constantly loaded. In addition, high-temperature solder reflow may be used for mounting each electronic component, and the number of processes may be used not only once but also for multiple solder reflow processes. It will be exposed to rapid heating and rapid cooling with a difference.

Therefore, there is a demand for a multilayer capacitor having high mechanical characteristics that can cope with an environment exposed to such severer thermal shock and stress in recent years while maintaining high dielectric characteristics.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a multilayer capacitor having particularly high mechanical characteristics.

That is, the present invention is as follows.
(1) In a multilayer capacitor having one surface and a facing surface,
A plurality of dielectric layers formed between the first surface and the facing, and dielectric material layer a plurality of internal electrode layers are stacked through, a plurality of electrically connected to each other internal electrode layer A via electrode, and an external electrode layer electrically connected to the via electrode and disposed on the one surface and / or the opposite surface,
The internal electrode layer, the via electrode and the external electrode layer are mainly composed of metallic nickel,
Together with the dielectric layer is composed mainly of barium titanate, it has a respective surface layer portion on one surface and the opposite side above, dielectric layer constituting the surface layer portion includes a metallic nickel on the entire layer ,
A multilayer capacitor comprising at least one external electrode layer connected with a plurality of the via electrodes .
(2) The multilayered capacitor according to (1), wherein the nickel metal contained in the surface layer portion is 3 to 30% by volume when each surface layer portion is 100% by volume.
(3) The multilayer capacitor according to (1) or (2), wherein each of the surface layer portions has a thickness of 10 to 100 μm.

According to the multilayer capacitor of the present invention, since the surface layer portion contains metallic nickel, a surface layer portion having a remarkably high mechanical strength can be obtained, and the mechanical strength of the entire multilayer capacitor can be increased. Furthermore, the adhesiveness with the external electrode layer which has metallic nickel as a main component is improved by containing metallic nickel in a surface layer part. In addition, by containing metallic nickel in the surface layer portion, the thermal conductivity of the surface layer portion is increased, the effect of equalizing the temperature in the multilayer capacitor is obtained, and the residual thermal stress between the internal electrode layer and the via electrode Is mitigated, and the occurrence of cracks and chipping during thermal shock and handling is effectively suppressed.
When the metal nickel contained in the surface layer part is 3 to 30% by volume when each surface layer part is 100% by volume, excellent mechanical strength can be obtained while maintaining high insulation.
When the thickness of the surface layer portions is 10 to 100 μm, it is possible to obtain more excellent mechanical strength while maintaining higher insulation.

It is a schematic sectional drawing of a multilayer capacitor. It is the schematic sectional drawing which expanded some surface layer parts. It is a schematic plan view explaining an example of the internal electrode layer of a multilayer capacitor, (a) represents the 1st group internal electrode layer, (b) represents the 2nd group internal electrode layer. It is a schematic plan view explaining the planar shape of an example of an external electrode layer. It is a schematic plan view explaining the planar shape of the other example of an external electrode layer. It is a general | schematic expanded sectional view explaining the cross-sectional shape of an example of the external electrode layer in which the plating layer was formed in the surface. It is explanatory drawing explaining the process of an example of the lamination | stacking method of a dielectric material layer and an internal electrode layer. It is explanatory drawing explaining the process of the other example of the lamination | stacking method of a dielectric material layer and an internal electrode layer. It is explanatory drawing explaining an example of an unbaking laminated body formation process. A connection area S _V of the non-fired via electrode unsintered outer electrode layer is an explanatory diagram for explaining a planar area S _O unfired external electrode layer. It is a schematic sectional drawing explaining an example of the wiring board with a built-in capacitor incorporating a multilayer capacitor. It is the chart by the X-ray powder diffraction measurement which shows the metallic nickel contained in the dielectric body confirmed in the Example.

[1] Multilayer Capacitor Hereinafter, the multilayer capacitor manufactured in the present invention will be described with reference to FIGS. For convenience, the same reference numerals are used before and after firing as the reference numerals of the respective parts.
The multilayer capacitor of the present invention is
In the multilayer capacitor having one side and the opposite side,
A plurality of dielectric layers formed between the first surface and the facing, and dielectric material layer a plurality of internal electrode layers are stacked through, a plurality of electrically connected to each other internal electrode layer A via electrode, and an external electrode layer electrically connected to the via electrode and disposed on the one surface and / or the opposite surface,
The internal electrode layer, the via electrode and the external electrode layer are mainly composed of metallic nickel,
Together with the dielectric layer is composed mainly of barium titanate, it has a respective surface layer portion on one surface and the opposite side above, dielectric layer constituting the surface layer portion includes a metallic nickel on the entire layer ,
A multilayer capacitor comprising at least one external electrode layer connected with a plurality of the via electrodes .
(2) The multilayered capacitor according to (1), wherein the nickel metal contained in the surface layer portion is 3 to 30% by volume when each surface layer portion is 100% by volume.
(3) The multilayer capacitor according to (1) or (2), wherein each of the surface layer portions has a thickness of 10 to 100 μm.

  The general shape of the “multilayer capacitor 100” is not particularly limited, but is usually a rectangular parallelepiped shape, and a plate shape is particularly preferable. The facing surface 100b of the multilayer capacitor 100 is a surface facing the one surface 100a of the multilayer capacitor 100, and these surfaces are arranged so that any of the surfaces faces upward, downward, or laterally when mounted (mounted). May be. Furthermore, the dielectric layer 110, the internal electrode layer 120, the via electrode 140, and the external electrode layer 150 constituting the multilayer capacitor 100 can be integrally formed by simultaneously firing the unfired body. Among these, the dielectric layer 110 and the internal electrode layer 120 are each a laminated body in which a plurality of layers are alternately laminated (a laminated body including only the dielectric layer 110 and the internal electrode layer 120 in the multilayer capacitor 100). Configure. Furthermore, a plurality of via electrodes 140 are usually formed in one multilayer capacitor 100, and these via electrodes 140 are arranged in an array.

  As shown in FIG. 1, the “dielectric layer 110” is a surface layer that is a dielectric layer disposed between the one surface 100 a and the internal electrode layer 120 on the one surface side (the internal electrode layer closest to the one surface 100 a). A surface layer portion 110b which is a dielectric layer disposed between the portion 110a, the facing surface 100b and the internal electrode layer 120 on the facing side (an internal electrode layer closest to the facing surface 100b), and other than the surface layer portion 110a and the surface layer portion 110b Dielectric layers (dielectric layers disposed between the internal electrode layers 120).

These dielectric layers 110 are mainly composed of barium titanate (BaTiO ₃ ). The phrase “mainly composed of barium titanate” means that barium titanate is contained at 95 volume% or more when the dielectric layer 110 is 100 volume%. This content is preferably 95 to 99% by volume and more preferably 96 to 98% by volume in dielectric layers other than the surface layer part 110a and the surface layer part 110b.
The content of barium titanate contained in the dielectric layer is measured by quantitative analysis with a wavelength dispersive X-ray spectrometer (WDX) of an electron probe microanalyzer (EPMA), and is calculated in terms of oxide.

  In addition to barium titanate, sintering aids and additives for barium titanate can be included. Examples of the sintering aid include silicon dioxide and silicate. Examples of the additive include calcium oxide, manganese dioxide, yttria (yttrium oxide), magnesium oxide, cobalt oxide, strontium oxide, and various rare earth oxides. Each of these sintering aids and additives may be contained alone or in combination of two or more. Especially, as an additive, 3 types combined use of calcium oxide, manganese dioxide, and yttria is preferable. Although content of a sintering aid and an additive is not specifically limited, Usually, it is 1-5 volume parts with respect to 100 volume parts of barium titanate.

  Further, in the dielectric layer 110, the surface layer portion 110a and the surface layer portion 110b contain metallic nickel, but, like the other dielectric layers 110, contain barium titanate as a main component. The surface layer part 110a or the surface layer part 110b contains 65% by volume or more of barium titanate when each of these is 100% by volume. In the surface layer part 110a and the surface layer part 110b, the content is preferably 65 to 96% by volume, and more preferably 65 to 95% by volume.

Although content of the metallic nickel in each of the surface layer part 110a and the surface layer part 110b is not specifically limited, when each of the surface layer part 110a and the surface layer part 110b is 100 volume% (100 mass%), 3-30 volume% ( 4.39-38.9% by mass), 5-30% by volume (7.2-38.9% by mass), especially 5-25% by volume (7.2-33.1% by mass). It is preferable (content may differ in the surface layer part 110a and the surface layer part 110b). When the content of metallic nickel is in the range of 3 to 30% by volume, dramatically high mechanical properties can be obtained while keeping the electrical resistivity low.
In addition, the volume ratio of the metallic nickel contained in the surface layer part is the area of the metallic nickel phase in the visual field because the contrast of light and dark is different in the reflected electron image (BEI) of the scanning electron microscope (SEM) obtained from the surface layer part cross section. As a ratio (which can be regarded as a volume ratio).

The thickness of the dielectric layer 110 is not particularly limited, but the thickness of the dielectric layer between the internal electrode layers 120 (that is, the dielectric layer other than the surface layer portion 110a and the surface layer portion 110b) is 1 to 10 μm, particularly 1 It is preferably ~ 5 μm.
On the other hand, the thickness of the surface layer part 110a and the surface layer part 110b is preferably 10 to 100 μm, more preferably 15 to 80 μm, still more preferably 20 to 70 μm, and particularly preferably 20 to 60 μm. However, the thickness of the surface layer portion 110a and the surface layer portion 110b may be the same or different. The surface layer portion 110a and the surface layer portion 110b are usually formed thicker than other dielectric layers, and the mechanical properties are improved by the inclusion of metallic nickel in the surface layer portion, and the internal electrode layer and the external electrode layer It is possible to obtain sufficient insulation.
The total number of the dielectric layers 110 is not particularly limited, but includes the surface layer portion 110a and the surface layer portion 100b (each of these layers is converted to one layer), for example, 30 to 200 layers, particularly 50 to 160 layers. be able to.

The metal nickel, the multilayer capacitor of the present invention, but Ru are contained throughout the surface layer portion 110a and the surface layer portion 110b, it may be contained in layers only on a part of the thickness direction. Of these, the surface layer part containing metallic nickel in a layer shape only in a part in the thickness direction is formed by laminating a plurality of unfired dielectric layers in the production of the multilayer capacitor, and forming the unfired surface layer part. When the surface layer portion is formed, it can be formed by including metallic nickel in only one portion of the plurality of unfired dielectric layers.

That is, as illustrated in FIG. 2, the surface layer portion 110a (the same applies to the surface layer portion 110b) is derived from four layers of green sheets, the layers 110a-1, 110a-2, 110a-3, when provided with a layer 110a-4 (which is integrated by actually firing each layer), the multilayer capacitor of the present invention, metallic nickel Ru are contained in all the layers of the layer 110a-. 1 to layer 110a-4. In the multilayer capacitor not included in the present invention, an aspect that is not included in both surface portions of the surface layer portion may be employed. That is, the layer 110a-1 and the layer 110a-4 do not contain metallic nickel, and the layer 110a-2 to the layer 110a-3 contain metallic nickel, or the layer 110a-1, the layer 110a-2, and the layer. 110a-4 does not contain metallic nickel, and the layer 110a-3 contains metallic nickel only, or the layers 110a-1, 110a-3 and 110a-4 contain no metallic nickel, For example, metallic nickel is included only in 110a-2. Thus, in an aspect in which metallic nickel is contained in a layer shape only in a part of the thickness direction excluding both surface portions of the surface layer portion, while realizing improvement in mechanical properties due to the inclusion of metallic nickel in the surface layer portion, Higher insulation between the internal electrode layer and the external electrode layer can be obtained. Further, this effect is effective in any mode as long as it has a configuration of three or more layers other than the four-layer configuration illustrated in FIG.
Note that the absence of metallic nickel means neither intentional inclusion nor intentional inclusion of metallic nickel, and when this region is subjected to X-ray diffraction measurement, It means that no peak is confirmed.

The “internal electrode layer 120” is a conductive layer disposed so as to face the dielectric layer 110. The internal electrode layer 120 contains metallic nickel as a main component. “Containing metal nickel as a main component” means that the content of metal nickel is 77.6% by mass or more (may be 100% by mass) when the internal electrode layer is 100% by mass. To do. This content is preferably 77.6-90.0% by mass, more preferably 77.6-85.6% by mass. Moreover, when another metal contains in a conductive material, the kind of this other metal is not specifically limited, For example, copper, tungsten, gold | metal | money, platinum, palladium, silver etc. are mentioned. These other metals may be contained alone or in combination of two or more. When two or more kinds are contained, they may be contained in the form of an alloy.
The content of metallic nickel contained in the internal electrode layer 120 is measured by EPMA. The same applies to the via electrode 140 and the external electrode layer 150.

The internal electrode layer 120 may contain other components excluding metals such as nickel. As other components excluding this metal, barium titanate constituting the dielectric layer 110 can be cited. By containing barium titanate in the internal electrode layer 120, the adhesion and bonding strength after firing of the internal electrode layer 120 and the dielectric layer 110 can be further improved. 1-30 volume% is preferable with respect to 100 volume% of internal electrode layers, as for content of barium titanate contained in an electrode, 5-30 volume% is more preferable, and 15-25 volume% is still more preferable.
The conductive material constituting the internal electrode layer 120 may have the same composition as or different from the conductive material constituting each of the via electrode and the external electrode layer described later. The same is preferable in terms of bonding strength and the like.

  The planar shape and thickness of the internal electrode layer 120 are not particularly limited, but the thickness is preferably thinner than the dielectric layer 110 between the internal electrode layers 120, more specifically 0.5 to 5 μm, particularly It is preferable that it is 0.5-2 micrometers. Furthermore, the number of layers (stacking number) of the internal electrode layers 120 is not particularly limited. For example, the number of layers may be one more than the dielectric layer 110 between the internal electrode layers 120.

  The “via electrode 140” is a conductor that electrically connects the plurality of internal electrode layers 120. The via electrode 140 is generally disposed through the plurality of dielectric layers 110 (including the surface layer portions 110a and 110b) and the plurality of internal electrode layers 120 in the stacking direction. Further, the end face of each via electrode 140 is connected to the external electrode layer 150. Furthermore, the via electrode 140 is electrically connected to a part of the internal electrode layer 120 on its side surface. The via electrode 140 contains metallic nickel as a main component, and contains 77.6 mass% or more (or 100 mass%) of metallic nickel when the via electrode 140 is 100 mass%. This content is preferably 77.6-90.0% by mass, more preferably 77.6-85.6% by mass. Further, as in the case of the internal electrode layer 120, this conductive material may contain other metals other than nickel and other components other than the metal.

  The “external electrode layer 150” is a conductor that is disposed on one surface 100 a and / or the opposite surface 100 b of the outer surface of the multilayer capacitor 100 and is electrically connected to the end surface of the via electrode 140. The external electrode layer 150 may be formed on both the one surface 100a and the facing surface 100b of the multilayer capacitor 100, or may be formed only on the one surface 100a or the facing surface 100b. The external electrode layer 150 can function as an external power supply terminal, a ground connection terminal, and the like in the multilayer capacitor 100.

The form of the external electrode layer 150 is not particularly limited, and may be (1) an electrode formed individually corresponding to each via electrode 140 (see FIG. 4), or (2) a plurality of via electrodes 140. Although the electrode may be shared (see FIG. 5) , the multilayer capacitor of the present invention includes (2) above . In the form of (1), the planar shape of each external electrode layer 150 is not particularly limited, but may be, for example, a circle, an ellipse, a quadrilateral or more, and a cross. These shapes may be the same or different in one multilayer capacitor 100. Furthermore, in the form of (2) above, the planar shape of the external electrode layer 150 is not particularly limited. For example, as in the case of the internal electrode layer 120, as described later, to avoid connection with other groups of via electrodes. It can be set as the continuous integral external electrode layer 150 provided with the clearance hole 153 (refer FIG. 5).

  Further, the external electrode layer 150 contains metallic nickel as a main component, and contains 77.6 mass% or more (or 100 mass%) of metallic nickel when the external electrode layer is 100 mass%. This content is preferably 77.6-90.0% by mass, more preferably 77.6-85.6% by mass. In addition, as in the case of the internal electrode layer 120 and the via electrode 140, the conductive material may contain other metals other than nickel and other components other than the metal.

  Furthermore, as illustrated in FIG. 6, the external electrode layer 150 has a plating layer 160 made of another metal on the outer surface (the surface not in contact with the dielectric layer 110 and the via electrode 140). Can do. When used as a wiring board with a built-in capacitor having a built-in multilayer capacitor as will be described later, copper can be used as the plating layer 160 because it has excellent connectivity with copper, which is widely used as a conductor of the wiring board. . Further, since it is more difficult to oxidize compared to metallic nickel, gold can be used as the plating layer 160. In addition, when the external electrode layer 150 contains a component other than a metal such as barium titanate, two or more layers are used in order to more fully adhere the external electrode layer 150 and the plating layer 160. The plating layer 160 can be obtained. That is, for example, two-layer plating of a metal nickel plating layer 162 formed in contact with the outer surface of the external electrode layer 150 and a gold plating layer 161 formed in contact with the outer surface of the metal nickel plating layer 162. It can be layer 160 (see FIG. 6).

Here, the correlation between the electrodes of the multilayer capacitor 100 will be described in detail.
The internal electrode layer 120, the via electrode 140, and the external electrode layer 150 included in the multilayer capacitor 100 are usually composed of at least two groups that are electrically insulated from each other. For example, the internal electrode layer 120 includes a first group of internal electrode layers 121 and a second group of internal electrode layers 122 insulated from the first group of internal electrode layers 121. Similarly, the via electrode 140 includes a first group of via electrodes 141 and a second group of via electrodes 142 that are insulated from the first group of via electrodes 141. Further, the external electrode layer 150 includes a first group of external electrode layers 151 and a second group of internal electrode layers 152 that are insulated from the first group of external electrode layers 151. Each electrically insulated group may be two groups as described above, or three or more groups.

  More specifically, the case of the two groups will be described. As shown in FIGS. 1 and 9, the first group of internal electrode layers 121, the first group of via electrodes 141, and the first group of external electrode layers 151. Are electrically connected to each other. The second group of internal electrode layers 122, the second group of via electrodes 142, and the second group of external electrode layers 152 are electrically connected to each other. The first group of internal electrode layers 121, the first group of via electrodes 141, and the first group of external electrode layers 151 include the second group of internal electrode layers 122, the second group of via electrodes 142, and the second group. It is insulated from the external electrode layer 152 of the group. Among these, the first group of internal electrode layers 121 and the second group of internal electrode layers 122 are insulated by being opposed to each other via the dielectric layer 110, thereby functioning as a capacitor. .

  In the first group and the second group, the first group of via electrodes 141 and the first group of internal electrode layers 121 are electrically connected, while the first group of via electrodes 141 and the second group of internal electrode layers are electrically connected. 122 is insulated through a clearance hole 123. Similarly, the second group of internal electrode layers 122 and the second group of via electrodes 142 are electrically connected, while the second group of via electrodes 142 and the second group of via electrodes 142 are electrically connected to each other. It is configured to be insulated from the group of internal electrode layers 121 via clearance holes 123 (see FIG. 3).

[2] Method for Manufacturing Multilayer Capacitor The method for manufacturing the multilayer capacitor of the present invention is not particularly limited. For example, the multilayer capacitor can be manufactured as follows.
The multilayer capacitor 100 includes an unsintered laminated body forming step (P1), a through-hole forming step (P2), an unfired via electrode forming step (P3), and an unfired external electrode layer forming step (P4). It can manufacture by the method of providing in order (refer FIG. 9).
Hereinafter, the unfired laminated body formed in the unfired laminated body forming step (P1) is referred to as “unfired first laminated body 131”, and the through-hole is formed in the unfired first laminated body in the through-hole forming step (P2). The formed laminate is “unfired second laminate 132”, and the laminate in which the unfired via electrode is formed on the unfired second laminate in the unfired via electrode formation step (P3) is referred to as “unfired third laminate”. Body 133 ”, and the laminate in which the unfired external electrode layer is formed on the unfired third laminate in the unfired external electrode layer forming step (P4) is referred to as“ unfired fourth laminate 134 ”.

  The unfired laminated body forming step (P1) includes an unfired dielectric layer 110 to be the dielectric layer 110, an unfired internal electrode layer 120 to be the internal electrode layer 120 formed by printing the internal electrode layer paste, Is a step of forming an unfired first laminated body 131 having a structure in which are alternately laminated. In addition, the unfired first laminated body 131 is formed with an unfired surface layer portion 110a on which the surface layer portion 110a on one side of the dielectric layer 110 is formed and a surface layer portion 110b on the facing side. And an unfired surface layer portion 110b.

The unsintered dielectric layer 110 (including the surface layer portions 110a and 110b) is an unsintered body that becomes the dielectric layer 110 after firing, and a barium titanate powder that forms the dielectric layer 110 and, if necessary. And a sintering aid powder. In addition, the unfired bodies that become the surface layer portion 110a and the surface layer portion 110b contain a barium titanate powder, a nickel component that gives metallic nickel after firing, and a sintering aid powder as necessary.
The nickel component may be any material, such as metallic nickel, nickel salt (used as powder and aqueous solution), nickel oxide, and other nickel compounds (excluding nickel salt and nickel oxide). It is done. These may use only 1 type and may use 2 or more types together. Among these, examples of the nickel salt include nickel nitrate, nickel carbonate, and nickel acetate. Examples of other nickel compounds include nickel hydroxide.

The nickel in the green body that becomes the surface layer part 110a and the surface layer part 110b may be contained in the form of nickel salt, nickel oxide, and other nickel compounds, but is preferably contained as metallic nickel. The metallic nickel may be formed by any method, but preferably, a barium titanate powder and a sintering aid powder and additive powder (CaO, SiO ₂ , MnO ₂ , Y ₂ O _3, etc.) for barium titanate. ) And a liquid in which a nickel salt is dissolved (water or an organic solvent can be used as a solvent), and the resulting paste is calcined in a reducing atmosphere (600 to 800 ° C.) To get it. The obtained calcined powder containing barium titanate, a sintering aid and metallic nickel and an organic component (binder, plasticizer, dispersant, solvent, etc.) are mixed and formed into a sheet to form a surface layer portion 110a and a surface layer. A green sheet serving as the portion 110b is obtained. The obtained green sheet may be used alone as an unsintered body that becomes the surface layer part 110a and the surface layer part 110b, or may be used as an unsintered body that becomes the surface layer part 110a and the surface layer part 110b.

The unfired internal electrode layer 120 is an unfired body formed using an internal electrode paste, and becomes the internal electrode layer 120 after firing. The unfired internal electrode layer 120 is usually formed by printing an internal electrode paste on the surface of the unfired dielectric layer 110. Furthermore, the internal electrode paste is printed so that clearance holes 123 are formed in order to insulate it from some of the via electrodes 140 as described with respect to the internal electrode layer 120. The shape of the clearance hole 123 is not particularly limited, but is usually circular (see FIG. 3). The dimensions are not particularly limited, but from the viewpoint of performance as a capacitor, it is preferable that the dimensions are within a range that can be sufficiently insulated and that the diameter is as small as possible. In particular, the ratio (H ₁ / H ₂ ) between the diameter H ₁ of the clearance hole 123 and the diameter H ₂ of the through hole for a via electrode described later is preferably 2 to 3.

  The internal electrode paste is a paste that forms the unfired internal electrode layer 120 by printing. This internal electrode paste contains, as a main component, metallic nickel particles that become the internal electrode layer 120 after firing. In addition, this paste usually contains ceramic powder such as barium titanate for improving the adhesion and bonding strength after firing with the dielectric layer 110. Moreover, organic components, such as an organic binder, a plasticizer, and a solvent, are contained for the purpose of adjusting the properties of the paste. Furthermore, when the total amount of metal particles is 100% by mass, the paste contains other metal particles of 1% by mass or less, for example, metal particles such as copper, tungsten, gold, platinum, palladium and silver. However, it is not particularly necessary to contain the metal particles, and the total amount of the metal particles is preferably metal nickel particles.

  Examples of the organic binder include celluloses such as alkyl cellulose (ethyl cellulose, methyl cellulose, etc.) and nitrocellulose, acrylic resins such as acrylic ester resins (polymethyl methacrylate, etc.), butyral resins such as polyvinyl butyral, phenol resins, and Polyester resin (alkyd resin etc.) etc. are mentioned. Examples of the plasticizer include phthalic acid esters (such as diethyl phthalate). The plasticizer is preferably selected and used depending on the type of organic binder. Furthermore, as solvents, ketone solvents (acetone, methyl ethyl ketone, etc.), hydrocarbon solvents (cyclohexane, toluene, etc.), monohydric alcohols (terpineol, butyl carbitol, etc.), and polyhydric alcohols (ethylene glycol, diethylene glycol, etc.) Etc. Only one type of organic binder, plasticizer and solvent may be used, or two or more types may be used in combination.

  The content of each component such as nickel particles, ceramic powder, and organic component contained in the internal electrode paste is not particularly limited. By including an appropriate amount of nickel particles, ceramic powder, organic components, etc., it is excellent in printability at the time of forming the unfired laminate, and in the correlation with the via electrode paste and the external electrode paste, This is preferable because the adhesion and the like are improved and a problem due to the difference in shrinkage behavior during firing does not occur.

  The unfired first stacked body 131 has a structure in which unfired dielectric layers 110 and unfired internal electrode layers 120 are alternately stacked. Further, an unfired surface layer portion 110a is provided on one side, and an unfired surface layer portion 100b is provided on the opposite side. The unfired first laminated body 131 is then fired after passing through the form of the unfired second laminated body 132, the unfired third laminated body 133, and the unfired fourth laminated body 134, and the multilayer capacitor 100 is formed. Manufactured.

  The method for forming the unfired first laminate 131 is not particularly limited, and can be formed by various methods. For example, after printing the unfired internal electrode layer 120 on the surface of each of the unfired dielectric layers 110, the unfired dielectric layer 110 provided with the unfired internal electrode layers 120 is formed on one side. The unfired first layered product 131 can be formed by stacking together the unfired surface layer part 110a formed on the surface and the unfired surface layer part 110b formed on the opposite side (see FIG. 7, unfired surface layer). (The parts 110a and 110b are not shown.) Further, after printing the unfired internal electrode layer 120 on one surface of the unfired dielectric layer 110, another unfired dielectric layer 110 is laminated so as to cover the unfired internal electrode layer 120, The unfired first laminated body 131 can also be formed by repeating the process of printing the unfired internal electrode layer 120 on the surface of another unfired dielectric layer 110 (see FIG. 8, unfired surface layer portion). 110a and 110b are not shown.)

  In the through-hole forming step (P2), a through-hole 132c penetrating between one surface and the opposite surface of the unfired first stacked body 131 is formed, and the unfired second stacked body 132 (unfired via electrode 140 is not filled). This is a step of forming an unfired laminated body having through-holes 132c (see FIG. 9). The method for forming the through-hole 132c is not particularly limited, and may be perforation by punching, perforation by laser light irradiation, or a combination of these methods. Furthermore, other methods may be used. Further, the diameter of the through hole 132c is not particularly limited, but is usually 50 μm or more, and particularly when the diameter of the through hole 132c (that is, the outer diameter of the unfired via electrode) is 70 to 140 μm, By doing so, adhesiveness can be improved more fully. This diameter is more preferably 85 to 130 μm.

  In the unfired via electrode formation step (P3), the via electrode paste is formed by filling the through hole 132c with the via electrode paste to form the unfired via electrode 140, and the unfired third stacked body 133 (unfired via electrode) 140 and a non-fired laminate having no green external electrode layer 150) (see FIG. 9). The method for filling the via electrode paste into the through-hole 132c is not particularly limited, and it may be filled by a printing method such as screen printing, may be filled using a dispenser, or these methods may be used in combination. Good. Furthermore, other methods may be used.

  The via electrode paste is a paste for forming the unfired via electrode 140 by filling the through hole 132c. This via electrode paste contains, as a main component, metallic nickel particles that become the via electrode 140 after firing. In addition, similar to the internal electrode paste, ceramic powder such as barium titanate, organic binder, plasticizer, solvent and the like are contained. Further, similar to the internal electrode paste, other metal particles may be contained, but it is not particularly necessary to contain them, and the total amount of the metal particles is preferably metal nickel particles. Furthermore, the content of each component such as nickel particles, ceramic powder, and organic component contained in the via electrode paste is not particularly limited, and an appropriate amount can be contained.

  In the unfired external electrode layer forming step (P4), the unfired external electrode layer 150 connected to the unfired via electrode 140 is formed by printing the paste for the external electrode layer on at least one of the one side and the opposite side. (See FIG. 9). By this unfired external electrode layer forming step, unfired fourth stacked body 134 (unfired stacked body having unfired via electrode 140 and unfired external electrode layer 150 connected thereto) is formed. The form of the unfired external electrode layer 150 that becomes the external electrode layer 150 after firing formed in this step is not particularly limited, and the description of the form of the external electrode layer 150 in the multilayer capacitor 100 can be applied as it is. it can.

  The external electrode layer paste is a paste that forms the unfired external electrode layer 150 by printing. This external electrode layer paste contains, as a main component, metallic nickel particles that become the external electrode layer 150 after firing. In addition, similar to the internal electrode paste, ceramic powder such as barium titanate, organic binder, plasticizer, solvent and the like are contained. Further, similar to the internal electrode paste, other metal particles may be contained, but it is not particularly necessary to contain them, and the total amount of the metal particles is preferably metal nickel particles. Furthermore, the content of each component such as nickel particles, ceramic powder, and organic component contained in the external electrode paste is not particularly limited, and an appropriate amount can be contained.

The shape and dimensions of the unfired external electrode layer 150 formed in the unfired external electrode layer formation step (P4) are not particularly limited as long as the external electrode layer 150 can be formed. contact area between the unfired outer electrode layer 150 of the firing via electrodes 140 (the area of the end face of the unfired via electrodes) and S _V, the area of one unfired external electrode layer 150 in case of the S _O, S _The dimensions are preferably _{O 2} / S _V ≧ 1.5 (see FIG. 10). That is, normally, the unfired external electrode layer 150 is preferably in contact with the entire end face of the unfired via electrode 140 in order to maximize the contact area with the unfired via electrode 140, but S _O / S _V ≧ If 1.5, the entire end face of the unfired via electrode 140 can be reliably brought into contact with the unfired external electrode layer 150.

  Furthermore, the larger the dimension of the unfired external electrode layer 150, the better the adhesion between the via electrode 140 and the dielectric layer 110 and the external electrode layer 150 can be improved. That is, the unfired external electrode layer shared by the plurality of via electrodes 140 as shown in FIG. 5 is formed rather than the unfired external electrode layer 150 corresponding to each individual via electrode 140 as shown in FIG. Forming 150 can remarkably improve the adhesion between the via electrode 140 and the dielectric layer 110 and the external electrode layer 150 after firing.

  The thickness of each unfired conductor constituting the fourth unfired stacked body 134 in the stacking direction is usually larger in the order of unfired internal electrode layer <unfired external electrode layer <unfired via electrode, and is fired in the stacking direction. Shrinkage also increases in this order. Therefore, as described above, by making the content of the ceramic powder contained in the unfired external electrode layer 150 and the unfired via electrode 140 greater than the content of the ceramic powder contained in the unfired internal electrode layer 120, Further, the firing shrinkage behavior of each conductor and the unfired dielectric layer 110 can be combined more effectively, and cracks and peeling after firing can be more effectively suppressed.

[3] Multilayer Capacitor for Capacitor-Incorporated Wiring Substrate The multilayer capacitor 100 of the present invention may be used as a single component as it is, but is particularly suitable as a multilayer capacitor for a capacitor-embedded wiring substrate (a multilayer capacitor for incorporating a substrate). is there.
The wiring board 10 with a built-in capacitor (see FIG. 11) usually has a board core part 20 and a capacitor part 21 (for example, the multilayer capacitor 100 of the present invention is housed) housed in the board core part 20. The semiconductor element 90 can be mounted, and at least build-up parts 30a and 30b stacked on both sides of the capacitor part 21 are provided.

The substrate core portion 20 is a core that accommodates the capacitor portion 21 and supports the entire wiring substrate 10. The substrate core 20 may be a simple plate-like body, but usually has a housing portion 201 that houses the capacitor portion 21. The accommodating part 201 is formed by a through hole and / or a bottomed hole provided in the substrate core part 20. Although the material which comprises the board | substrate core part 20 is not specifically limited, It is preferable to use the polymeric material which has heat resistance, such as an epoxy resin, a polyimide resin, a bismaleimide triazine resin, a polyphenylene ether resin. Further, in order to obtain the substrate core portion 20 having more excellent strength and thermal characteristics, glass fiber, glass fiber woven fabric, glass fiber nonwoven fabric, polyamide fiber, polyamide fiber nonwoven fabric, polyamide fiber woven fabric and the like are provided as a core material. Also good.
In addition, the through-hole conductor 202 which conducts the upper surface side 20a and the lower surface side 20b can be provided in the substrate core part 20 as shown in FIG. This through-hole conductor may be filled in the entire interior of the through-hole, but the other part except the through-hole conductor 202 formed on the wall surface of the through-hole may be closed with an insulating hardened body 203. .

  The capacitor unit 21 includes the multilayer capacitor 100 of the present invention housed in the substrate core unit 20. The capacitor unit 21 is usually fixed in the storage unit 201 with a filler 204 such as a resin material such as an epoxy resin while being stored in the substrate core unit 20 (see FIG. 11).

  The build-up portions 30a and 30b are usually stacked on both sides of the substrate core portion 20 and the capacitor portion 21 accommodated in the substrate core portion 20, and are composed of conductor layers (31a and 31b) and interlayer insulating layers (32a and 32b). Are alternately laminated, and the outermost layer is usually provided with resist layers (321a and 321b). The build-up portions 30a and 30b may be formed only on one surface side of the wiring substrate 10, but are usually formed on both surface sides and further preferably formed symmetrically in the stacking direction. In general, there is a large difference between the terminal pitch of the connection terminals 311a on the semiconductor element 90 side of the capacitor built-in wiring board 10 and the terminal pitch of the connection terminals 311b on the motherboard side of the capacitor built-in wiring board 10. Therefore, by providing the build-up portions 30a and 30b, the pitch can be freely adjusted in the build-up portions 30a and 30b, so that the wiring board 10 can be adjusted from the upper surface side (semiconductor element mounting side) to the lower surface side (motherboard mounting side). It is possible to output different pitches between terminals (see FIG. 11).

  In addition, the material constituting the interlayer insulating layers 32a and 32b of the build-up portions 30a and 30b is not particularly limited, but a heat-resistant polymer material such as an epoxy resin, a polyimide resin, a bismaleimide / triazine resin, or a polyphenylene ether resin is used. It is preferable to use it. Furthermore, the conductor layers 31a and 31b constituting the build-up portions 30a and 30b may be electrically connected to other conductor layers through vias or the like as necessary. When using vias, they may be stacked in a non-stacked via method (each via may be a filled via or a conformal via) that is connected to avoid being directly above each via. A stacked via method in which a via is formed immediately above (each via is usually a filled via) may be stacked. The form of each via may be the same or different between the buildup portion 30a on the upper surface side and the buildup portion 30b on the lower surface side.

Hereinafter, the present invention will be specifically described by way of examples.
[1] Characteristic evaluation of barium titanate containing metallic nickel (1) Confirmation of inclusion of metallic nickel In mixed powder in which barium titanate powder and sintering aid powder (calcium oxide powder, manganese dioxide powder and yttria powder) were mixed, A liquid in which a nickel salt (nickel nitrate) was dissolved in a solvent (ethanol) was added and wet mixed. Thereafter, the mixture was dried and calcined at 700 to 800 ° C. in a reducing atmosphere to obtain a calcined powder. The obtained calcined powder was subjected to X-ray powder diffraction measurement (X-ray diffraction measurement device, manufactured by Rigaku Corporation, format “Miniflex”) to obtain an X-ray diffraction chart shown in FIG. From the obtained peak, a peak of barium titanate and a peak of metallic nickel were recognized, but a peak of nickel oxide was not recognized (see FIG. 12).

(2) Evaluation of three-point bending strength Eight types of calcined powders having different metallic nickel contents were obtained in the same manner as (1) above. After adding a binder, a dispersant and a solvent, granulation was performed to obtain a granulated powder. The obtained granulated powder was powder press-molded and then degreased and fired (fired at 1100 to 1300 ° C. in a reducing atmosphere) to obtain coarse pieces. The surface of the obtained rough piece was ground and the metal nickel content was 0% by volume, 5% by volume, 10% by volume, 15% by volume, 20% by volume, 25% by volume, 30% by volume and 35% by volume. Eight types of test pieces for measuring the three-point bending strength (6 mm × 4 mm × 25 mm square columnar test pieces) were obtained.
Using the obtained test piece, three-point bending strength was measured at a span interval of 16 mm and a bending speed of 0.5 mm / min. The results are shown in Table 1.

(3) Evaluation of electrical resistivity After granulating each granulated powder obtained using 8 types of calcined powder in the same manner as in (2) above, degreasing and firing (1100 to 1300 ° C. in a reducing atmosphere) To obtain coarse pieces. The surface of the obtained rough piece was ground and the metal nickel content was 0% by volume, 5% by volume, 10% by volume, 15% by volume, 20% by volume, 25% by volume, 30% by volume and 35% by volume. The eight types of test pieces for electrical resistivity measurement (thickness 1 mm × diameter 14-15 mm disk-shaped test pieces) were obtained. Silver electrodes (diameter 14 mm) were formed by baking on the front and back surfaces of the obtained test piece, and the electrical efficiency when a voltage of 100 V was applied for 60 seconds using a high resistance meter (manufactured by Hewlett Packard, model “4339B”) The results are shown in Table 1.

(4) Evaluation of thermal conductivity In the same manner as (3) above, the metal nickel content is 0% by volume, 5% by volume, 10% by volume, 15% by volume, 20% by volume, 25% by volume, 30% by volume. And eight kinds of test pieces for measuring thermal conductivity (disk-shaped test pieces having a thickness of 1 to 2 mm and a diameter of 9 to 10 mm) of 35% by volume. The obtained test piece was set to an initial steady temperature of 30 ° C. using a thermal conductivity measuring device, and the thermal conductivity was measured by a laser flash method. In addition, the density of each test piece was measured by the Archimedes method. The results are shown in Table 1.

(5) Evaluation of firing shrinkage (fired at 1300 ° C.) In the same manner as in (3) above, the metal nickel content is 0% by volume, 5% by volume, 10% by volume, 15% by volume, 20% by volume, 25% by volume. %, 30% by volume, and 35% by volume of test pieces for measuring the baking shrinkage rate (3 mm × 3 mm × 20 mm square columnar test pieces) were obtained. After degreasing the obtained test piece at 200 to 350 ° C., a thermomechanical analyzer (manufactured by Rigaku Corporation, model “TMA8310”, an alumina piece having a known length and a constant load applied to both ends of the above test piece The shrinkage rate when the temperature was raised to 1300 ° C. at a rate of 5 ° C. per minute was measured using a device that records the expansion and contraction with respect to the temperature through a detection rod. The results are shown in Table 1.

尚、金属ニッケルの体積含有率（焼成後の各誘電体層１００体積％に含まれる金属ニッケルの体積割合）を質量含有率（焼成後の各誘電体層１００質量％に含まれる金属ニッケルの質量割合）に換算すると、５体積％は７質量％、１０体積％は１４質量％、１５体積％は２１質量％、２０体積％は２７質量％、２５体積％は３３質量％、３０体積％は３９質量％、３５体積％は４４質量％、である。

The volume content of metallic nickel (volume ratio of metallic nickel contained in 100% by volume of each dielectric layer after firing) is the mass content (mass of metallic nickel contained in 100% by weight of each dielectric layer after firing). 5% by volume is 7% by mass, 10% by volume is 14% by mass, 15% by volume is 21% by mass, 20% by volume is 27% by mass, 25% by volume is 33% by mass, and 30% by volume is 39% by mass and 35% by volume are 44% by mass.

[2] Thermal shock evaluation by via array type multilayer capacitor (1) Production of green sheet to be unfired dielectric layer 9 types (metal nickel after firing) with different metal nickel contents as in [1] (1) Nine types of calcined powders having a content of 0 vol%, 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol% and 35 vol% were obtained. A slurry was prepared by mixing the obtained calcined powder with a butyral binder, a plasticizer and a solvent. Next, using this slurry, a sheet was formed by a doctor blade method, and then heated to remove the solvent to produce a green sheet. For the green sheet, a 20 μm thick green sheet (15 μm after firing) and a 5 μm thick green sheet (3 μm after firing) were prepared, and the 20 μm thick one was used for the surface layer. A thickness of 5 μm was used for the other dielectric layers.

(2) Preparation of conductive paste (a) Internal electrode paste Metal nickel powder, barium titanate powder and organic components (organic binder, plasticizer and solvent) were wet mixed to prepare an internal electrode paste.
(B) Via electrode paste Metal nickel powder, barium titanate powder and organic components (organic binder, plasticizer and solvent) were wet mixed to prepare a via electrode paste.
(C) External electrode layer paste External nickel electrode layer paste was prepared by wet mixing metallic nickel powder, barium titanate powder and organic components (organic binder, plasticizer and solvent).

(3) Unbaked laminate forming step (P1)
The green sheet obtained in (1) above and the various pastes obtained in (2) above are combined to form the unfired internal electrode layer 120 and the unfired surface layer portion 110b having the structure shown in Table 2. An unsintered laminated portion in which unsintered internal electrode layers and unsintered dielectric layers obtained by laminating and press-bonding unsintered dielectric layer 110 on which unsintered internal electrode layer 120 is formed are alternately stacked, unsintered surface layer An unfired first laminated body 131 was formed in which the unfired surface layer portion 110a having the same configuration as the portion 110b was laminated and pressure-bonded in this order.

(4) Through-hole forming step (P2)
Via holes 132c were drilled in the unfired first laminate 131 formed in the above (3) with a laser to form an unfired second laminate 132.

(5) Unfired via electrode formation step (P3)
The via electrode paste prepared in (2) and (b) above is filled into the via hole 132c formed in the unfired second laminated body 132 formed in (4) by screen printing, and the unfired via electrode 140 is filled. An unsintered third laminated body 133 having the structure was formed.

(6) Unfired external electrode layer forming step (P4)
The external electrode layer paste prepared in (2) and (c) above was screen-printed on the surface of the unfired third laminate 133 formed in (5) to form the unfired external electrode layer 150. An unsintered fourth laminate 134 was formed.

(7) Firing step The unfired fourth laminate 134 formed in (6) above was degreased in a nitrogen atmosphere, and then fired at 1100 to 1400 ° C in a humidified nitrogen-hydrogen mixed gas atmosphere. 80 multilayer capacitors 100 of ˜17 (Examples; Experimental Examples 10-15, Comparative Example; Experimental Examples 9 and 16, Reference Example; Experimental Example 17 ) were manufactured.
The obtained multilayer capacitor 100 has an overall thickness of 0.8 mm, an average dielectric layer thickness of 3 μm, a total of 150 dielectric layers disposed between the internal electrode layers, an average surface layer thickness of 60 μm, and a surface portion constituting layer number of 4 Layer (integrated by firing), average internal electrode layer thickness 1 μm, total number of internal electrode layers 150.

  On the other hand, the unfired third laminated body 133 formed in the above (5) is not subjected to the above (6) unfired external electrode layer forming step (P4), that is, without forming an external electrode layer, in a nitrogen atmosphere. And then calcined at 1100 to 1400 ° C. in a humidified nitrogen-hydrogen mixed gas atmosphere. Examples 9 to 17 (Examples; Experimental Examples 10 to 15 and 17, Comparative Examples; Experimental Examples 9 and 16) 80 multilayer capacitor test pieces each having no external electrode layer were produced. The multilayer capacitor specimen having no external electrode layer was subjected to a thermal shock test described later and used for crack generation evaluation.

(8) Thermal shock test The multilayer capacitor having the external electrode layer obtained up to the above (7) is sandwiched with tweezers, immersed in a molten solder bath without preheating, and taken out after 2 seconds to cause thermal shock. added. In this thermal shock, the bath temperature was set so that the temperature difference (thermal shock temperature difference) was 250 ° C., 270 ° C., and 300 ° C., and was imposed on 10 multilayer capacitors at each temperature.
Thereafter, the multilayer capacitor was cut in the thickness direction (direction in which the multilayer cross section can be visually observed), the cut surface was polished, and the polished surface was observed with an optical microscope to confirm the presence or absence of the following delamination and the presence or absence of the following cracks.
The delamination between the layers is a delamination between the inner electrode layer adjacent to the surface layer portion and the surface layer portion that can be visually confirmed on a screen magnified 200 times with an optical microscope. The number of multilayer capacitors where one or more delaminations are recognized is converted and shown in Table 2 as a percentage of the total number of tests.
The crack is a crack confirmed in the surface layer portion that can be confirmed by a fluorescent flaw detection method. The number of multilayer capacitors in which one or more cracks were observed was converted and shown in Table 2 as a percentage of the total number of tests.

(9) Evaluation of resistance value between terminals A probe terminal of a high resistance meter (model “R8340A” manufactured by Advantest Corporation) is brought into contact with a terminal of a multilayer capacitor having an external electrode layer subjected to a thermal shock test, and a voltage of 20 V is applied. The resistance value between terminals was measured by applying for 2 seconds and shown in Table 2.

尚、表２中の表層部の「配分」における、１層目は、図２における層１１０ａ−１（１１０ｂ−１）に対応し、２層目は、図２における層１１０ａ−２（１１０ｂ−２）に対応し、３層目は、図２における層１１０ａ−３（１１０ｂ−３）に対応し、４層目は、図２における層１１０ａ−４（１１０ｂ−４）に対応する。

Note that the first layer in the “distribution” of the surface layer portion in Table 2 corresponds to the layer 110a-1 (110b-1) in FIG. 2, and the second layer corresponds to the layer 110a-2 (110b− in FIG. 2). Corresponding to 2), the third layer corresponds to the layer 110a-3 (110b-3) in FIG. 2, and the fourth layer corresponds to the layer 110a-4 (110b-4) in FIG.

  According to the results of Table 1, in the multilayer capacitor (Experimental Examples 2 to 7) in which the content of metallic nickel in the surface layer portion is 5 to 30% by volume, compared with the multilayer capacitor not containing metallic nickel (Experimental Example 1), A remarkable improvement in mechanical properties of 2 to 6.9 times is recognized, and an electrical resistivity higher by about 11 orders than a multilayer capacitor (Experimental Example 8) having a metal nickel content of 35% by volume and 68% or less. And a low thermal conductivity. Furthermore, it turns out that the baking shrinkage rate in 1300 degreeC is also restrained small in Experimental Examples 2-7.

Moreover, according to the result of Table 2, it turns out that the thermal shock resistance is remarkably improved by containing 5 volume% or more of metallic nickel in a surface layer part. That is, delamination was observed in Experimental Example 9 containing no metallic nickel, but none of the temperatures was observed in Experimental Examples 10 to 17 containing metallic nickel. Furthermore, by comparing the experimental example 16 with other experimental examples, it can be seen that the resistance value between terminals can be improved by about 4 orders of magnitude by setting the content of metallic nickel to 30% by volume or less. Moreover, the crack could be further remarkably reduced by setting the metal nickel content to 15 to 30% by volume.
Furthermore, when the metal nickel content is the same, the surface layer portion has a wide surface layer by making the metal nickel intensively contained only in a part of the thickness direction excluding both surface portions of the surface layer portion. It can be seen from the comparison between the experimental example 13 and the experimental example 17 that superior insulating properties can be obtained as compared with the embodiment in which the dispersion is contained in the range.

In addition, in this invention, it can restrict to what is shown to said specific Example, It can be set as the Example variously changed within the range of this invention according to the objective and the use.
Although not included in the present invention, for example, other blending examples of metallic nickel in the surface layer part include (1) 10% by volume of the first layer, 10% by volume of the second layer, and 10% by volume of the third layer. The fourth layer has a volume of 0% by volume, and the entire surface layer portion contains 7.5% by volume of metallic nickel. (2) 10% by volume of the first layer, 10% by volume of the second layer, 0 of the third layer The volume% and the fourth layer may be 0 volume%, and the entire surface layer portion may contain 5 volume% metallic nickel.
Further, although not included in the present invention, the metallic nickel contained in the surface layer portion in the present invention can be functionally substituted with metallic cobalt. However, metallic cobalt is more expensive than metallic nickel and is difficult to substitute in terms of cost.

100; multilayer capacitor (unfired multilayer capacitor), 100a; one side, 100b;
110; dielectric layer (unfired laminated dielectric layer), 110a; surface layer portion, 110b; surface layer portion,
120; internal electrode layer (unfired laminated internal electrode layer), 121; first group of internal electrode layers, 122; second group of internal electrode layers,
131; unfired first laminate, 132; unfired second laminate, 133; unfired third laminate, 134; unfired fourth laminate,
140; via electrode (unfired via electrode),
150; external electrode layer (unfired external electrode layer),
160; plating layer, 161; outer surface plating layer, 162; interlayer plating layer,
10; capacitor built-in wiring board,
20; Substrate core portion, 201; Housing portion, 204; Filler, 202; Through-hole conductor, 203; Cured body, 21; Capacitor portion (multilayer capacitor), 30a; Build-up portion on the upper surface side, 30b; Build-up part, 31a, 31b; conductor layer, 311a, 311b; connection terminal (connection terminal on the surface of the capacitor built-in wiring board), 32a, 32b; interlayer insulation layer, 321a, 321b; solder resist layer,
90: Semiconductor element.

Claims (3)

In the multilayer capacitor having one side and the opposite side,
A plurality of dielectric layers formed between the first surface and the facing, and dielectric material layer a plurality of internal electrode layers are stacked through, a plurality of electrically connected to each other internal electrode layer A via electrode, and an external electrode layer electrically connected to the via electrode and disposed on the one surface and / or the opposite surface,
The internal electrode layer, the via electrode and the external electrode layer are mainly composed of metallic nickel,
Together with the dielectric layer is composed mainly of barium titanate, it has a respective surface layer portion on one surface and the opposite side above, dielectric layer constituting the surface layer portion includes a metallic nickel on the entire layer ,
A multilayer capacitor comprising at least one external electrode layer connected with a plurality of the via electrodes .   2. The multilayer capacitor according to claim 1, wherein the metal nickel contained in the surface layer part is 3 to 30% by volume, with each surface layer part being 100% by volume. 3.   The multilayer capacitor according to claim 1 or 2, wherein each of the surface layer portions has a thickness of 10 to 100 µm.

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