JP2010183024A - 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; a dielectric layer for composing respective surface layer sections 110a, 110b at one face side and at the opposing face side includes stabilized zirconia and 2-7 mol% of stabilizing agent to 100 mol% of stabilized zirconia; and the stabilized zirconia included in the surface layer section has 3-30 vol.% each when each surface layer section has 100 vol.%. <P>COPYRIGHT: (C)2010,JPO&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 one surface and the facing surface, a plurality of internal electrode layers stacked via the dielectric layers, and via electrodes electrically connecting the internal electrode layers 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,
The dielectric layer is mainly composed of barium titanate, and the dielectric layer constituting each surface layer portion on the one surface side and the opposite surface side contains stabilized zirconia, and the stabilized zirconia includes When the total amount is 100 mol%, it contains 2-7 mol% stabilizer,
Stabilized zirconia contained in the surface layer part is 3 to 30% by volume when each surface layer part is 100% by volume.
(2) The multilayer capacitor according to (1), wherein the thickness of the surface layer portion is 10 to 100 μm.
(3) The multilayer capacitor according to (1) or (2), wherein the stabilized zirconia is contained in at least one of the internal electrode layer, the via electrode, and the external electrode layer.
(4) The multilayer capacitor according to any one of (1) to (3), wherein the stabilizing zirconia stabilizer is at least one of a rare earth element oxide, CaO, and MgO.

According to the multilayer capacitor of the present invention, since the surface layer portion contains 3 to 30% by volume of stabilized zirconia, 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. Can do. For this reason, when a thermal shock is applied or when handling, occurrence of cracks and chipping is effectively suppressed. In particular, the present multilayer capacitor mainly composed of nickel metal as each electrode is subjected to reduction firing at the time of manufacture, but the stabilizer contained in the stabilized zirconia contained in the surface layer portion is 2 to 7 mol%, Even after reduction firing, high mechanical properties and insulation can be obtained.
When the thickness of the surface layer portions is 10 to 30 μm, it is possible to obtain more excellent mechanical strength while maintaining higher insulation.
When stabilized zirconia is contained in at least one of the internal electrode layer, the via electrode, and the external electrode layer, the adhesion with these electrodes is improved.
When the stabilizing zirconia stabilizer is at least one of rare earth oxides, CaO and MgO, zirconia particles having excellent mechanical properties, particularly strength and toughness, can be dispersed and composited.

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.

[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 one surface and the facing surface, a plurality of internal electrode layers stacked via the dielectric layers, and via electrodes electrically connecting the internal electrode layers 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,
The dielectric layer is mainly composed of barium titanate, and the dielectric layer constituting each surface layer portion on the one surface side and the opposite surface side contains stabilized zirconia, and the stabilized zirconia includes When the total amount is 100 mol%, it contains 2-7 mol% stabilizer,
The stabilized zirconia contained in the surface layer part is 3 to 30% by volume when each surface layer part is 100% by volume.

  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). Constitute. 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.

  Of the dielectric layer 110, the surface layer portion 110 a and the surface layer portion 110 b contain stabilized zirconia, 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.

The stabilized zirconia content in each of the surface layer part 110a and the surface layer part 110b is 3 to 30% by volume (3 to 30%) when each of the surface layer part 110a and the surface layer part 110b is 100% by volume (100% by mass). Mass%). The content is preferably 5 to 30% by volume (5 to 30% by mass), more preferably 5 to 25% by volume (5 to 25% by mass) (contained in the surface layer part 110a and the surface layer part 110b). Amount may vary). When the content of the stabilized zirconia 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 stabilized zirconia contained in the surface layer part is the stabilized zirconia phase occupied 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 cross section of the surface layer part. Area ratio (which can be regarded as a volume ratio).

The stabilized zirconia means stabilized zirconium oxide, and contains 2 to 7 mol% of a stabilizer. The type of the stabilizer is not particularly limited, and examples thereof include rare earth oxides such as yttria, calcium oxide, and magnesium oxide. These stabilizers may use only 1 type and may use 2 or more types together.
The stabilized zirconia may be either fully stabilized zirconia or partially stabilized zirconia, but partially stabilized zirconia is preferred. The content of the stabilizer is not particularly limited as long as it is 2 to 7 mol%. However, when the total stabilized zirconia is 100 mol%, 2 to 6 mol% is preferable in terms of oxide, and 2 to 5.7. The mol% is more preferable, and 3.5 to 5.5 mol% is particularly preferable. In the oxide conversion, Y is converted to Y ₂ O ₃ , Ca is converted to CaO, and Mg is converted to MgO.

In the multilayer capacitor of the present invention, yttria is particularly preferable among the stabilizers. Furthermore, the content is preferably 2.0 to 5.7 mol%, more preferably 3.5 to 5.5 mol%, based on 100 mol% of stabilized zirconia.
Since the main component of the electrode of this multilayer capacitor is nickel, it is fired in a non-oxidizing atmosphere (including a reducing atmosphere). Thus, when calcination is performed in a non-oxidizing atmosphere, particularly in a reducing atmosphere, by using stabilized zirconia having a stabilizer of 2 to 7 mol%, high mechanical properties can be obtained even after reducing calcination. And insulation can be obtained.

The stabilizer is contained as a solid solution in the zirconium oxide, but is shown as each most stable oxide. That is, for example, yttria as a stabilizer functions by dissolving yttrium in zirconium oxide.
The content of the stabilizer in the stabilized zirconia is usually measured only by EPMA, but yttria is used as a sintering aid for barium titanate constituting the dielectric layer, and the stabilizer is also used. In the case of yttria, the stabilized zirconia particles are discriminated in the backscattered electron image (BEI image), the content of yttrium contained in any 10 stabilized zirconia particles is measured by EPMA, and the measured value obtained Is calculated as an average molar fraction after converting to oxide as Y ₂ O ₃ .

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 to 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 20 to 70 μm, still more preferably 20 to 60 μm, and particularly preferably 15 to 25 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 the other dielectric layers, and improve the mechanical characteristics by containing stabilized zirconia in the surface layer portion. A sufficient insulation of the layers can be obtained.
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.

  Moreover, the stabilized zirconia may be contained over the whole surface layer part 110a and the surface layer part 110b, and may be contained in a layer form only in a part in the thickness direction. Among these, the surface layer portion containing the stabilized zirconia 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 portion. When the surface layer portion is fired, it can be formed by containing stabilized zirconia in only one part 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 the layer 110a-4 is provided (actually, each layer is integrated by firing), the stabilized layers may contain the stabilized zirconia in all the layers 110a-1 to 110a-4. It can also be set as the aspect which is not contained in a surface part. That is, the layer 110a-1 and the layer 110a-4 do not contain the stabilized zirconia, and the layer 110a-2 to the layer 110a-3 include the stabilized zirconia, the layer 110a-1 and the layer 110a-2. And the layer 110a-4 does not contain stabilized zirconia, and the layer 110a-3 contains only stabilized zirconia, and the layers 110a-1, 110a-3 and 110a-4 contain stabilized zirconia. For example, the stabilized zirconia is contained only in the layer 110a-2. As described above, in the aspect in which the stabilized zirconia is contained only in a part of the thickness direction excluding both surface portions of the surface layer portion, the improvement of the mechanical properties is realized by the inclusion of the stabilized zirconia in the surface layer portion. However, 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.
The absence of stabilized zirconia means that there is neither intentional inclusion nor stabilized zirconia due to intentional intercalation, and when this region is measured by EPMA, the Zr element Means not 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. Stabilized zirconia is mentioned as another component except this metal. As the stabilized zirconia, the stabilized zirconia contained in the surface layer part 110a and the surface layer part 110b can be applied as it is. However, the stabilized zirconia contained in the surface layer portion and the stabilized zirconia contained in the electrode may have the same or different contents of the stabilizer. By containing the stabilized zirconia in the electrode, a multilayer capacitor having further excellent mechanical characteristics can be obtained, and delamination and cracks in the multilayer capacitor can be more effectively suppressed. The content of the stabilized zirconia contained in the electrode is preferably 1 to 30% by volume, more preferably 1 to 15% by volume, and still more preferably 2 to 10% by volume with respect to 100% by volume of the internal electrode layer.

Furthermore, the internal electrode layer 120 can contain other components in addition to the stabilized zirconia. Examples of the other component include barium titanate constituting the dielectric layer 110. 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. In addition, as in the case of the internal electrode layer 120, the 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. The electrode may be shared (see FIG. 5). 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 unfired dielectric layer 110 (including the surface layer portions 110a and 110b) is an unfired body that becomes the dielectric layer 110 after firing, and barium titanate powder that forms the dielectric layer 110 and, if necessary, And sintering aid powder. In addition, for the unsintered body (hereinafter also simply referred to as “unsintered surface layer part”) to be the surface layer part 110a and the surface layer part 110b, a barium titanate powder, the stabilized zirconia powder, and, if necessary, a sintering aid powder Etc. are contained.

The unsintered surface layer portion includes, for example, a mixed powder containing a barium titanate powder and a sintering aid powder (CaO, SiO ₂ , MnO ₂ , Y ₂ O _3, etc.) for the barium titanate and a stabilizer of 2 to 2 After mixing 7 mol% of stabilized zirconia powder, the obtained paste is calcined (600 to 800 ° C.) in a reducing atmosphere. The obtained calcined powder containing barium titanate, sintering aid and stabilized zirconia and organic components (binder, plasticizer, dispersant, solvent, etc.) are mixed and formed into a sheet to form a surface layer portion 110a. And the green sheet used as the surface layer part 110b is obtained. The obtained green sheet may be used alone as an unfired body that becomes the surface layer portion 110a and the surface layer portion 110b, or may be used as an unfired surface layer portion after being multilayered.

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, the paste can contain ceramic powder such as barium titanate and stabilized zirconia for improving 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.

  Organic binders include acrylic resins, celluloses such as alkyl cellulose (ethyl cellulose, methyl cellulose, etc.) and nitrocellulose, acrylic ester resins such as polymethyl methacrylate, butyral resins such as polyvinyl butyral, phenolic resins, and polyesters. 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). 110a and 110b are not shown.) Further, after printing the unfired internal electrode layer 120 on one surface of one unfired dielectric layer 110, another unfired dielectric layer 110 is laminated so as to cover the unfired internal electrode layer 120, and then 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 110a). 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 and stabilized zirconia, an organic binder, a plasticizer, a 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 surface and the opposite surface. (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 and stabilized zirconia, an organic binder, a plasticizer, a 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.

[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 substrate incorporation). 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 polymer material having heat resistance 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 stabilized zirconia (1) Evaluation of three-point bending strength Powder obtained by mixing barium titanate powder, sintering aid powder (yttria powder and calcia powder) and stabilized zirconia powder Got.
As the stabilized zirconia, 12 types (see Table 1, Experimental Examples 2 to 13) having different types and contents of stabilizers were used. Experimental Example 1 does not contain stabilized zirconia. Furthermore, the barium titanate and the sintering aid are BaTiO ₃ : Y ₂ O ₃ : CaO = 97.7% by mass (100% by volume) after sintering. 97.3 volume%): 1.4 mass% (1.4 volume%): 0.9 mass% (1.3 volume%).

The obtained mixed powder, binder, dispersant and solvent were mixed and granulated 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 13 kinds of three-point bending strength measurement test pieces (6 mm × 4 mm × 25 mm square prism shape) having a stabilized zirconia content of 0 to 35% by volume. Test piece) was 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.

(2) Evaluation of electrical resistivity After granulating each granulated powder obtained using 13 types of calcined powder in the same manner as in (1) above, powder degreasing and firing (1100 to 1300 ° C in a reducing atmosphere) To obtain coarse pieces. The surface of the obtained rough piece is ground, and 13 kinds of test pieces for measuring electrical resistivity (thickness 1 mm × diameter 14 to 15 mm disk having a stabilized zirconia content of 0 to 35% by volume) Shape test piece) was 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.

表１中、「＊」は本発明の範囲外であることを示す。

In Table 1, “*” indicates that it is outside the scope of the present invention.

  The volume content of stabilized zirconia in Table 1 (volume ratio of stabilized zirconia contained in 100% by volume of each dielectric layer after firing) is included in 100% by mass of each dielectric layer after firing. In terms of mass ratio of stabilized zirconia), Experimental Example 2 is 3% by mass, Experimental Example 3 is 5% by mass, Experimental Example 4 is 10% by mass, Experimental Example 5 is 15% by mass, and Experimental Example 6 is 20% by mass. %, Experimental Example 7 is 25% by mass, Experimental Example 8 is 30% by mass, Experimental Example 9 is 35% by mass, Experimental Example 10 is 15% by mass, Experimental Example 11 is 20% by mass, Experimental Example 12 is 20% by mass, Experimental example 13 is 5 mass%.

[2] Thermal shock evaluation by via array type multilayer capacitor (1) Preparation of green sheet to be unfired dielectric layer [1] In the same manner as in (1), the content of stabilized zirconia, the content of stabilizer or Different types of stabilizers (see Table 2) 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 Internal nickel electrode powder, barium titanate powder, stabilized zirconia powder and organic components (organic binder, plasticizer and solvent) are wet mixed to prepare internal electrode paste. did.
(B) Paste for via electrode A paste for via electrode was prepared by wet-mixing metallic nickel powder, barium titanate powder, stabilized zirconia powder and organic components (organic binder, plasticizer and solvent).
(C) External electrode layer paste An external electrode layer paste was prepared by wet mixing metallic nickel powder, barium titanate powder, stabilized zirconia 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. To 29 (Examples; Experimental Examples 16 to 22, Experimental Examples 25 to 26 and Experimental Example 28, Comparative Examples; Experimental Examples 14 to 15, Experimental Examples 23 to 24, Experimental Examples 27 and 29) 80 pieces were produced each.
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. Experimental Examples 14 to 29 (Examples; Experimental Examples 16 to 22, Experimental Examples 25 to 26 and Experimental Example 28, Comparative Example) 80 multilayer capacitor test pieces each having no external electrode layer of Experimental Examples 14 to 15, Experimental Examples 23 to 24, Experimental Example 27, and Experimental Example 29) were manufactured. 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 is cut in the thickness direction (direction in which the multilayer cross section can be seen), the cut surface is polished, and the inner layer electrode layer and the surface layer portion adjacent to the surface layer portion on a screen in which the polished surface is magnified 200 times by an optical microscope Separation between layers (interlaminar separation) was visually observed. As a result, the number of multilayer capacitors in which at least one delamination was observed was converted and shown in Table 3 as a percentage of the total number of tests.

On the other hand, the multilayer capacitor having no external electrode layer obtained up to the above (7) was sandwiched between tweezers, immersed in a molten solder bath without preheating, and subjected to thermal shock by taking it out after 2 seconds. . 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 presence or absence of cracks (cracks confirmed on the surface layer portion) on the surface of the multilayer capacitor was confirmed by a fluorescent flaw detection method. As a result, the number of multilayer capacitors in which one or more cracks were observed was converted and shown in Table 3 as a percentage of the total number of tests.

(9) Evaluation of resistance value between terminals A probe terminal of a high resistance meter (manufactured by Advantest Corporation, model “R8340A”) is brought into contact with a terminal of a multilayer capacitor having an external electrode layer before being subjected to a thermal shock test, and a voltage of 20V Was applied for 30 seconds, and the resistance value between the terminals was measured.

表２中、「＊」は本発明の範囲外であることを示す。また、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。

In Table 2, “*” indicates that it is outside the scope of the present invention. Further, in the “distribution” of the surface layer portion in Table 2, the first layer 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.

表３中、「＊」は本発明の範囲外であることを示す。

In Table 3, “*” indicates that it is outside the scope of the present invention.

[3] Effects of Examples According to the results in Table 1, in test pieces (stabilized examples 2 to 8 and 10 to 12) containing stabilized zirconia containing 2 to 7 mol% of a stabilizer in the surface layer portion, Compared to the test piece containing no stabilized zirconia (Experimental Example 1), an improvement in mechanical properties of 1.8 to 3.7 times was observed, and a test piece having a stabilized zirconia content of 35% by volume (experimental) As compared with Example 9), it was possible to obtain an electrical resistivity higher by two orders or more.

In addition, it can be seen that Experimental Example 13 in which the stabilizing agent contained in the stabilized zirconia is 8 mol% has a lower three-point bending strength than Experimental Example 1 that does not contain the stabilized zirconia. That is, in the multilayer capacitor that has undergone reduction firing, although the mechanical properties are improved by including the stabilized zirconia in the surface layer portion, the use of the stabilized zirconia in which the amount of the stabilizer is 8 mol% or more is mechanical. It turns out that it becomes a factor which reduces a characteristic conversely. Furthermore, the electrical resistivity in Experimental Example 13 is 80 Ω · m, which is lower than that of the other experimental examples by 9 orders or more. From this phenomenon as well, the content of the stabilizer contained in the stabilized zirconia is low. It can be seen that it needs to be lower than 8 mol%.
Although the reason why such a phenomenon occurs is not clear, the stabilized zirconia is reduced by reduction firing, resulting in a component having conductivity, resulting in a decrease in electrical resistivity and a decrease in mechanical properties. Can be considered.

  Moreover, according to Table 2 and Table 3, in Experimental example 14 (comparative example), since the surface layer part does not contain the stabilized zirconia, it turns out that delamination and a crack have arisen. Further, in Experimental Example 15 (Comparative Example), although the surface layer portion contains stabilized zirconia, the content is too small at 2% by volume, resulting in the same delamination and cracks as in Experimental Example 14. No superiority due to the inclusion of stabilized zirconia was observed over Experimental Example 14. Moreover, even if 10 volume% of stabilized zirconia was contained only in the outermost surface layer portion (first layer) of the surface layer portion from the result of Experimental Example 24, the content of the entire surface layer portion was 2.5 volume. %, And no superiority due to containing stabilized zirconia was observed over Experimental Example 14.

  Furthermore, in Experimental Example 23 (comparative example) in which the stabilized zirconia content was 35% by volume, cracks were observed at both Δ250 ° C. and Δ280 ° C., and delamination occurred at any temperature. From this result, it can be seen that both the delamination resistance and crack resistance characteristics are degraded as compared with Experimental Example 22 (Example) in which the stabilized zirconia content is 30% by volume. Further, no superior delamination resistance was observed as compared with Experimental Example 14 (Comparative Example) in which the stabilized zirconia content was 0% by volume.

  In Experimental Example 24, only the first layer of the surface layer portion contains stabilized zirconia in an appropriate amount (10% by volume for only one layer), but the content relative to the entire surface layer portion. Is 2.5% by volume, so that delamination occurred at any temperature, and the rate of cracking greatly increased as the thermal shock increased. From this, the superiority by containing stabilized zirconia was not recognized with respect to Experimental example 14 (comparative example). Furthermore, in Experimental Example 27, although the surface layer portion contains stabilized zirconia, the content of the stabilizer contained in the stabilized zirconia is excessive as 8 mol%, and thus delamination and cracks are generated. I understand that. Further, in Experimental Example 29, although stabilized zirconia is contained in the surface layer portion, it can be seen that the content of the stabilizer contained in the stabilized zirconia is too small at 1 mol%, so that it cannot be skillfully fired.

  In contrast to these results, Experimental Example 16 (Example) has a stabilized zirconia content of 3% by volume and only 1% by volume of Experimental Example 15, but delamination is significantly improved. No delamination was observed at any temperature of 250 to 300 ° C. Similarly, in Experimental Examples 16 to 22 in which the content of stabilized zirconia was 3 to 30% by volume, no delamination was observed, and crack resistance was improved as the content of stabilized zirconia was increased. In particular, in Experimental Examples 19 to 22, it can be seen that between 250 and 280 ° C., no delamination and no cracks are observed and extremely high thermal shock resistance is obtained. In addition, when Experimental Examples 16 to 22 are compared, it can be seen that even if the content of stabilized zirconia is increased, the change in the inter-terminal resistivity is hardly recognized, and high insulation is maintained.

  From the results of Table 1 and Tables 2 to 3, by having a surface layer part containing 3 to 30% by volume of stabilized zirconia having a stabilizer content of 2 to 7 mol%, it has a particularly high heat resistance. It can be seen that impact properties can be obtained.

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.
That is, for example, as other blending examples of stabilized zirconia in the surface layer part, (1) 10% by volume of the first layer, 10% by volume of the second layer, 10% by volume of the third layer, and 0% by volume of the fourth layer The entire surface layer portion may contain 7.5% by volume of stabilized zirconia. (2) 10% by volume of the first layer, 10% by volume of the second layer, 0% by volume of the third layer, 0 of the fourth layer The total surface layer portion may be 5% by volume of stabilized zirconia or may be configured.

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, S; thickness center plane,
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 (4)

In the multilayer capacitor having one side and the opposite side,
A plurality of dielectric layers formed between the one surface and the facing surface, a plurality of internal electrode layers stacked via the dielectric layers, and via electrodes electrically connecting the internal electrode layers to each other 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,
The dielectric layer is mainly composed of barium titanate, and the dielectric layer constituting each surface layer portion on the one surface side and the opposite surface side contains stabilized zirconia, and the stabilized zirconia includes When the total amount is 100 mol%, it contains 2-7 mol% stabilizer,
Stabilized zirconia contained in the surface layer part is 3 to 30% by volume when each surface layer part is 100% by volume.   The multilayer capacitor according to claim 1, wherein each of the surface layer portions has a thickness of 10 to 100 μm.   The multilayer capacitor according to claim 1, wherein stabilized zirconia is contained in at least one of the internal electrode layer, the via electrode, and the external electrode layer.   4. The multilayer capacitor according to claim 1, wherein the stabilizing zirconia stabilizer is at least one of a rare earth element oxide, CaO, and MgO. 5.

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