JPH10335115A - Ceramics composite laminated component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of cracks and delamination in a ceramics composite laminated part manufactured by laminating more than one ceramics part. SOLUTION: A part has two ceramics part 2 and 3 adjacent to each other via an intermediate laminate 100, the intermediate laminate 100 is formed by alternately laminating ceramics layers 5a, 5b, and 5c of a ceramic material included in one ceramics part 2, and the other ceramics layers 32a, 32b, and 32c of a ceramics material included in the other ceramics part 3, totaling more than two layers. Nearer they are to the ceramics part 2, the thicker the ceramics layers 5a, 5b, and 5c are made, and nearer they are to the ceramics part 3, the thicker the other ceramics layers 32a, 32b, and 32c are made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic composite laminated part in which two or more functional parts are laminated.

[0002]

2. Description of the Related Art In recent years, with the rapid development of semiconductor devices and semiconductor circuits such as MPUs and their applied products, the use of semiconductor devices and semiconductor circuits in personal computers, measuring instruments, home appliances, communication devices, power devices and the like has become widespread. The miniaturization and high performance of these devices are rapidly progressing. However, despite these advances, the withstand voltage, surge and noise immunity of these devices and their components have not been satisfactory. Therefore, protecting these devices and components from abnormal surges and noises and stabilizing the circuit voltage have become extremely important issues. In order to solve these problems, there has been a demand for the development of an inexpensive voltage non-linear resistance element (varistor) having extremely large voltage non-linearity, large energy withstand capability, large surge withstand capability, excellent life characteristics, and low cost. I have.

Conventionally, varistors generally used are:
It is mainly composed of strontium titanate (SrTiO ₃ ), zinc oxide (ZnO) and the like. Among them, a varistor containing zinc oxide as a main component (hereinafter, referred to as a zinc oxide varistor) generally has features such as a low limiting voltage and a large voltage nonlinear coefficient. Therefore, it is suitable for protection against overvoltage of a device composed of a device having a small overcurrent capability such as a semiconductor device.

[0004] However, not all noise can be absorbed by the zinc oxide varistor alone. Zinc oxide varistors
Due to the mechanism of exhibiting such characteristics, it has no effect on noise with a fast rise, for example, noise with a short wavelength of 10 ns or less, and cannot be said to be sufficient as an antistatic component.
Conventionally, a combination of a capacitor and a resistor has been used to absorb such short wavelength noise. However, since the combination of the capacitor and the resistor has no voltage limiting ability, there is a problem that an overvoltage is applied and the capacitor and the circuit are destroyed. Further, since it has no surge absorbing ability, it is ineffective for a large surge current such as a lightning surge.

[0005] In order to cope with both fast rising noise and overcurrent, a varistor and a capacitor are conventionally mounted in parallel. However, in order to mount each element on a printed wiring board by itself, it is necessary to form an electrode for each element, solder a lead wire, and seal with a resin. It is also necessary to perform soldering by inserting it into a hole in the substrate. Therefore, there has been a demand for a multifunctional element that can make use of the advantages of the zinc oxide varistor and the capacitor and that can be reduced in size and thickness.

On the other hand, for example, Japanese Patent Application Laid-Open No. 63-3291
Japanese Patent Laid-Open No. 1 (1994) proposes a noise absorbing element having a structure in which a varistor and a capacitor are integrated. This noise absorbing element is formed by integrally forming a first laminated body composed of a varistor material and an electrode and a second laminated body composed of a capacitor material and an electrode. It is structured to take advantage of. The gazette states that
As a varistor material, a material in which a small amount of Bi ₂ O ₃ is added to ZnO or a material in which a small amount of a semiconductor element such as Sb ₂ O ₃ is added to TiO ₂ is disclosed.
₃ are disclosed. However, in the combination of the varistor material and the capacitor material disclosed in the publication, since the heat shrinkage curves of the two materials are greatly different, remarkable warpage occurs at the time of simultaneous firing, and commercialization is not possible in terms of appearance. It becomes possible, peeling is promoted due to poor adhesion, or large internal stress is generated near the interface between the varistor material and the capacitor material, causing cracks and delamination.

Japanese Patent Application Laid-Open No. 1-283915 also discloses a multilayer device having a structure in which a varistor and a capacitor are integrated, as in Japanese Patent Application Laid-Open No. 63-32911. In this case, there is a problem that a large internal stress is generated due to a difference in thermal expansion coefficient between the varistor material and the capacitor material.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ceramic composite laminated part in which two or more ceramic parts are laminated, such as a ceramic composite laminated part in which a varistor part and a capacitor part are laminated and integrated. The purpose is to suppress the occurrence of lamination.

[0009]

The above object is achieved by the following (1).
And (2) are achieved. (1) A ceramic composite laminated part in which at least two ceramic parts are laminated, wherein two ceramic parts adjacent to each other via an intermediate laminated body are present, and the intermediate laminated body is provided on one of the two ceramic parts. One ceramic layer made of a ceramic material included,
The ceramics layer is formed by alternately laminating a total of three or more ceramic layers made of a ceramic material included in the other of the two ceramic parts in total, and when one of the ceramic layers is present, the one ceramic layer Among them, the one closer to the one ceramic part is thicker,
In the case where there are a plurality of the other ceramic layers, a ceramic composite laminated component that is thicker as the other ceramic layer is closer to the other ceramic component. (2) The ceramic composite laminated component according to the above (1), wherein two ceramic components adjacent via the intermediate laminate are a ceramic component having a varistor function and a ceramic component having a capacitor function.

[0010]

In the ceramic composite laminated part of the present invention, the intermediate laminated body having the above-mentioned structure is provided between two adjacent ceramic parts, so that the interface between the two ceramic parts depends on the difference in the physical constant (mainly the coefficient of thermal expansion). The internal stress generated in the vicinity can be sufficiently reduced. For this reason, it is possible to prevent the occurrence of cracks near the interface. In addition, when the present invention is applied to a ceramic component having a structure in which a ceramic layer and an electrode layer are stacked, delamination can be prevented.

Further, since internal stress can be reduced, it is not necessary to match physical constants such as thermal expansion coefficient between two adjacent parts, and as a result, the development period of the composite laminated part can be shortened.

Conventionally, a gradient composition region having an intermediate composition may be provided between the two materials in order to relieve stress when joining different materials. In this case, a material having a gradient composition is used. It needs to be newly manufactured. On the other hand, in the present invention, it is not necessary to produce a ceramic material having a new composition, and therefore, the production is easy.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The ceramic composite laminated part of the present invention is obtained by laminating at least two ceramic parts, and further has at least one intermediate laminated body described later. The intermediate laminate exists between two ceramic parts.

The intermediate laminate alternates between one ceramic layer made of a ceramic material contained in one adjacent ceramic component and another ceramic layer made of a ceramic material contained in the other adjacent ceramic component. Are laminated. Both ceramic layers are present in a total of three or more layers. That is, at least one of the ceramic layers is present in plurality. The plurality of ceramic layers have different thicknesses from each other,
In addition, they are arranged in the order of thickness in the intermediate laminate. Specifically, when there are a plurality of the one ceramic layers, the ceramic layers are arranged so that the thicker one is closer to the one ceramic part. Further, when there are a plurality of the other ceramic layers, they are arranged so that the thicker one is closer to the other ceramic part.

By providing the intermediate laminate having such a structure between two types of ceramic parts mainly composed of ceramic materials having different thermal expansion coefficients, the internal stress generated near the boundary between the two parts can be sufficiently relaxed. . In addition, it is considered that element diffusion between one ceramic layer and the other ceramic layer also contributes to relaxation of the internal stress.
Element diffusion between the two ceramic layers can be confirmed by EPMA (electron probe microanalysis) or the like.

The number of ceramic layers included in the intermediate laminate is not particularly limited, and may be appropriately determined so that internal stress can be sufficiently reduced. Preferably, each ceramic layer has two or more layers, and more preferably each ceramic layer has at least two layers. 2 for both ceramic layers
To 5 layers. If the number of the ceramic layers is too large, the thickness of the intermediate laminate becomes large, and the size of the composite laminate component increases, and the effect of alleviating the internal stress hardly improves. Note that the number of one ceramic layer and the number of the other ceramic layer need not be the same.

The maximum value and the minimum value of the thickness of each ceramic layer included in the intermediate laminate are not particularly limited, and may be appropriately determined so that the internal stress can be sufficiently relaxed.
Normally, the minimum value of the thickness is preferably 5 to 30 μm, and the maximum value of (thickness value) /
(Minimum thickness) is preferably about 2 to 5.
If the minimum value of the thickness is too small, it is difficult to contribute to the relaxation of the internal stress. If (the maximum value of the thickness) / (the minimum value of the thickness) is too small or too large, the effect of relaxing the internal stress is reduced.

In the intermediate laminate, one ceramic layer decreases in thickness and the other ceramic layer increases in thickness from one component side to the other component side. In the ceramic layer, the pattern of decreasing or increasing the thickness is not particularly limited. For example, the thickness difference between adjacent ceramic layers of the same type via different types of ceramic layers may be a constant value, the thickness ratio may be a constant value, There may be.

When the number of ceramic parts of the ceramic composite laminated part is n (n ≧ 2), the number of intermediate laminated bodies is 1 to n−1. Since the intermediate laminate is provided to reduce stress generation due to a difference in thermal expansion coefficient between adjacent ceramic components, internal stress is particularly likely to occur.
It may be provided between two components as appropriate, and need not be provided at all between adjacent components.

Varistor-Capacitor Composite Laminated Parts FIG. 1 shows a structural example of the ceramic composite laminated parts of the present invention. The ceramic composite laminated part shown in FIG.
It is a stack of different types of ceramic parts.
One ceramic component is a varistor portion 2 having a varistor function, and the other ceramic component is a capacitor portion 3 having a capacitor function.

An intermediate laminate 100 exists between the varistor portion 2 and the capacitor portion 3. A pair of terminal electrodes 41 and 42 are provided on the outer surface of the device body 10, which is a laminate of these three members. I have.

The varistor section 2 includes a varistor internal electrode 21.
There is at least one varistor layer 22 sandwiched between them.
A pair of varistor internal electrodes 21 sandwiching the varistor layer 22 includes:
It is exposed on the opposite side surface of the element body 10 and connected to terminal electrodes 41 and 42 formed on each side surface. The varistor portion 2 includes a buffer layer 5 described later,
It exists in contact with 00. On the other hand, the capacitor section 3 has at least one dielectric layer 32 sandwiched between the capacitor internal electrodes 31. A pair of capacitor internal electrodes 31 sandwiching the dielectric layer 32 are exposed on the opposite side surfaces of the element body 10 similarly to the varistor internal electrodes 21, and are connected to terminal electrodes 41 and 42 formed on the respective side surfaces. The varistor part 2 and the capacitor part 3 are electrically connected in parallel.

The varistor internal electrode 21 and the capacitor internal electrode 31 adjacent to each other with the interface between the varistor section 2 and the capacitor section 3 interposed therebetween are arranged so that they have the same potential. Try not to join.

In the intermediate laminate 100, the buffer layers 5 a, 5 b, and 5 c are stacked from the varistor portion 2 side with a dielectric layer interposed therebetween, and the buffer layer closer to the varistor portion 2 is thicker. That is, the thickness of the buffer layer increases in the order of 5c, 5b, and 5a. The dielectric layers 32a, 32b, and 32c are stacked from the capacitor unit 3 side with a buffer layer interposed therebetween, and the dielectric layers closer to the capacitor unit 3 are thicker, that is, the dielectric layers are 32c, 32b, The thickness increases in the order of 32a. Buffer layer 5 in intermediate laminate
Reference numerals a, 5b, and 5c denote ceramic layers made of the same material as the buffer layer 5 included in the varistor portion 2. Also, the dielectric layers 32a, 32b, 32c in the intermediate laminated body
Is a ceramic layer made of the same material as the dielectric layer 32 included in the capacitor section 3.

Next, a preferred configuration of each part of the varistor-capacitor composite laminated component shown in FIG. 1 will be described.

Varistor Layer The varistor layer preferably contains zinc oxide as a main component and at least one oxide of an element selected from lanthanides as a subcomponent. As a lanthanide, L
a, Pr, Nd, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb and Lu are preferred. When two or more lanthanides are used, the mixing ratio is arbitrary.

In this specification, the content of the oxide in the varistor layer and the dielectric layer is expressed in terms of an oxide having a stoichiometric composition as described below.

The content of zinc oxide in terms of ZnO is preferably at least 80% by weight, more preferably 85 to 99% by weight. If the amount of zinc oxide is too small, it tends to deteriorate in a load life test in a high-temperature, high-humidity atmosphere.

The content of the lanthanide oxide is preferably 0.05 to 8% by weight. If the content is too small, the voltage non-linearity will be poor, and if the content is too large, the energy resistance will be small. Incidentally, the content of lanthanide oxide,
When R is the lanthanide, it is expressed in terms of R ₂ O ₃ . However, Pr oxide is expressed in terms of Pr ₆ O ₁₁ .

It is preferable that the varistor layer contains at least zinc oxide and lanthanide oxide, but it is preferable to add a sub-component other than lanthanide oxide as needed. The auxiliary component added to the varistor layer containing zinc oxide as a main component is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-201531 by the present applicant, and the varistor layer in the present invention is also conventionally known. Preferred compositions can be used.

Hereinafter, specific examples of the auxiliary components other than the lanthanide oxide will be described.

It is preferable that the auxiliary component contains a Co oxide. The content of Co oxide in terms of Co ₃ O ₄ is preferably 0.1 to 10% by weight. If the content is too small, the voltage non-linearity will be poor, and if the content is too large, the energy resistance will be small.

The subcomponents include B and A among the IIIb group elements.
It is preferable that at least one of the oxides of l, Ga and In is contained. The total content of these oxides is preferably 1 × 10 ^-4 to 1 × 10 ^-1 weight in terms of B ₂ O ₃ , Al ₂ O ₃ , Ga ₂ O ₃ and In ₂ O _3. %. If the content is too small, the limiting voltage becomes too large, and if the content is too large, the leak current increases.

The sub-component may contain a Pb oxide. Pb oxide improves the energy resistance. P
The content of b-oxide in terms of PbO is preferably 2% by weight or less, more preferably 1% by weight or less. If the content is too large, the energy resistance may be rather reduced.

The subcomponent may contain at least one of V, Ge, Nb and Ta oxides and / or a Bi oxide. The total content of each oxide of V, Ge, Nb, and Ta is V ₂ O ₅ , GeO ₂ , Nb ₂
It is preferably not more than 0.2% by weight in terms of O ₅ and Ta ₂ O ₅ , and the content of the latter in terms of Bi ₂ O ₅ is preferably not more than 0.5% by weight. The effect of these additions is to improve the voltage nonlinear coefficient. However, if the content thereof is too large, the voltage nonlinear coefficient may be rather reduced.

The auxiliary component may contain at least one of Cr and Si oxides. C of Cr oxide
The content in terms of r ₂ O ₃ is preferably 0.01 to 1% by weight, and the content of Si oxide in terms of SiO ₂ is preferably 0.001 to 0.
5% by weight.

The auxiliary component may contain at least one of the oxides of K, Rb and Cs among the Group Ia elements. These are respectively K ₂ O, Rb ₂ O and Cs ₂ O
The total content when converted to is preferably 0.01 to 1
% By weight.

The sub-components include Mg and C among the group IIa elements.
At least one of the oxides of a, Sr and Ba may be contained. These are respectively MgO, CaO, S
The total content in terms of rO and BaO is preferably 0.01 to 4% by weight.

The thickness and the number of layers of the varistor layers (the number existing between the varistor internal electrodes) are not particularly limited, and may be appropriately set according to the required varistor characteristics.
Usually, it is 5-200 μm, preferably 10-100 μm, and the number of laminations is usually 1-30, preferably 10-20
It is.

Dielectric Layer The dielectric layer is preferably composed mainly of titanium oxide or an oxide containing La and Ti. Specifically, an oxide having a composition centered on TiO ₂ or La ₂ Ti ₂ O ₇ is preferable. The main components are La ₂ O ₃ and TiO ₂
When converted to, the content of TiO ₂ is preferably 1% by weight.
And more preferably at least 20% by weight.
It is at most 00% by weight, preferably at most 80% by weight, more preferably at most 50% by weight. The content of TiO ₂ in La ₂ Ti ₂ O ₇ was 28.17% by weight, and the content of La ₂ O ₃ was 71.17% by weight.
83% by weight. The content of the main component oxide is preferably at least 70% by weight of the whole dielectric layer, more preferably 90% by weight.
% By weight or more, more preferably 97% by weight or more.

The dielectric layer may contain various subcomponents other than the above main components. Manganese oxide is preferred as an accessory component. Manganese oxide is added to improve the temperature characteristics of the capacitance of the capacitor section. The device of the present invention can be used usually in a temperature range of about -55 to 125 ° C. The content of manganese oxide in terms of MnO is preferably 3% by weight or less, more preferably 0.1 to 10% by weight.
3% by weight.

The dielectric layer preferably contains glass in addition to the above main components and subcomponents. In order to approximate the heat shrinkage curve at the time of firing the dielectric layer to the heat shrinkage curve at the time of firing the varistor layer, this glass is obtained by mixing glass powder with a dielectric material and firing, and as a result, is present in the dielectric layer. It is.

The glass composition is not particularly limited, as long as it can control the heat shrinkage curve as described above. Preferably, borosilicate glass is used. As the borosilicate glass, a zinc borosilicate glass containing zinc oxide is preferable. By using the glass containing zinc oxide, the compatibility with the adjacent varistor layer and buffer layer is improved. The zinc oxide content in the glass is preferably 20 to 70% by weight in terms of ZnO.

The softening point of the glass is preferably 400 to 8
00 ° C.

The glass content of the dielectric layer is preferably 0.1 to 5% by weight. If the content is too small, the effect of adding glass becomes insufficient, and if the content is too large, it becomes difficult to obtain good capacitor characteristics. By adding borosilicate glass within this range, the heat shrinkage curve of the dielectric layer can be sufficiently approximated to that of the varistor layer.

The thickness of the dielectric layer and the number of layers (the number existing between the capacitor internal electrodes) are not particularly limited, and may be appropriately set according to the required capacitor characteristics. 20 μm, preferably 5 to 10 μm, and the number of layers is usually 1 to 50, preferably 10 to 20
It is.

The internal electrode varistor internal electrode and capacitor internal electrode are fired simultaneously with the varistor layer and the dielectric layer. Therefore, the conductive material used for the internal electrode is Ag, Ag alloy, Pd
And the like may be appropriately selected from those used in conventional multilayer chip capacitors. As the Ag alloy, for example, Ag-Pd, Ag-Pt, Ag-Pd-Pt and the like are preferable. The varistor internal electrode and capacitor internal electrode
Usually, the same conductive material may be used.

The thickness of the internal electrode is usually 1 to 5 μm.

Terminal electrode The terminal electrode may be selected from the conductive materials mentioned in the description of the internal electrode and used. However, since the terminal electrode is usually formed after the element body is fired, it is fired at a low temperature. Is possible. Therefore, an Ag-based conductive material that needs to be fired at a low temperature can be used for the terminal electrode.

The thickness of the terminal electrode is preferably 30 to 60.
μm.

When the composite component of the present invention is used as a surface mount component, it is soldered on a wiring board. Therefore, it is necessary to provide a plating film on the surface of the terminal electrode in order to improve solder wettability and solder breakability. Is preferred. As such a plating film, a Sn film or a Sn—Pb film is preferable. In addition, Ag of the terminal electrode when plating Sn or Sn-Pb is used.
In order to prevent cracking, it is preferable to provide a plating film of Ni or Cu on the surface of the terminal electrode as a base of these plating films.

Buffer Layer In the composite varistor-capacitor component of FIG. 1, a buffer layer 5 is provided on the varistor part 2 on the interface side with the capacitor part 3. This buffer layer 5 is composed of the varistor layer 2
2 of the dielectric layer 32 and the specific resistance of the dielectric layer 32, and preferably has a higher specific resistance than the lower one.
2 and the specific resistance of the dielectric layer 32. The reason for providing the buffer layer 5 is as follows.

When a varistor layer and a dielectric layer having the above composition are fired simultaneously, mutual diffusion of elements occurs near the interface between the two layers during firing. Specifically, subcomponents, particularly Mn, diffuse mainly from the dielectric layer, and subcomponents, particularly Co, Cr, and lanthanides (particularly, Pr) also diffuse from the varistor layer. Due to this diffusion, the specific resistance near the interface between the two layers, particularly near the interface between the varistor layers, is reduced, thereby forming a low specific resistance region. Since the low resistivity region has a lower resistivity than the original varistor layer, a short circuit occurs.
This causes an increase in leakage current and a decrease in the voltage nonlinear coefficient. On the other hand, if the buffer layer is provided, a low resistivity region will not be formed even if mutual diffusion of elements occurs, so that deterioration of element characteristics can be prevented.

The constituent material of the buffer layer is not particularly limited as long as the specific resistance after firing satisfies the above relationship, and various insulating materials such as magnesia, mullite, titania and the like can be used. However, in consideration of the adhesion between the varistor layer and the dielectric layer and the matching of the heat shrinkage curve, it is preferable to use an oxide mainly comprising an oxide constituting the varistor layer and / or an oxide constituting the dielectric layer. . And, in general, the varistor layer has a lower specific resistance than the dielectric layer,
Further, since the varistor layer has a greater decrease in specific resistance due to the above-described element diffusion, it is most preferable that the buffer layer be formed from an oxide mainly composed of varistor layer constituent oxides. belongs to.

The preparation composition (raw material composition) of the buffer layer mainly composed of the oxide constituting the varistor layer may be obtained by appropriately changing the contents of the subcomponents of the varistor layer so as to obtain a high specific resistance after firing. . Specifically, subcomponents in the charge composition, particularly Co, Cr, lanthanide (particularly Pr)
Of the varistor layer is preferably 1.2 to 5 times, more preferably 1.5 to 3 times
More preferably, the amount of each of these oxides alone is excessive in such a range. However, Al among the subcomponent constituent elements does not add to the buffer layer because it acts as a donor and lowers the specific resistance. The excessively added subcomponent element mainly exists at the grain boundary, suppresses the growth of crystal grains during firing, serves as a potential barrier, and increases the specific resistance. Further, even after the element diffusion due to the firing, sufficient subcomponents remain in the buffer layer, so that the specific resistance after firing can be made higher than that of the varistor layer.
In addition, since the buffer layer does not contain Al, the specific resistance also increases.

The thickness of the buffer layer is not particularly limited, and may be such a thickness that diffusion of elements from the varistor layer and the dielectric layer does not substantially affect each other, but is preferably 1 μm or more. , More preferably 5 μm or more. Although there is no particular upper limit on the thickness of the buffer layer, the thickness of the buffer layer generally does not need to exceed 100 μm, and is usually 80 μm.
The following is sufficient. In addition, the thickness of a region (hereinafter, referred to as an element diffusion region) in which an element diffuses from an adjacent layer having a different composition system in the buffer layer is usually about 1 to 50 μm.

The specific resistance of the element diffusion region of the buffer layer is preferably 10 ¹⁰ to 10 ¹³ Ω · cm. The specific resistance of the buffer layer other than the element diffusion region is even higher. On the other hand, the specific resistance of the varistor layer is usually 10 ⁸ to 10 ¹² Ω.
Cm, the specific resistance of the dielectric layer is usually 10 ¹¹ to 10 ¹³
It is about Ω · cm.

In the example shown in FIG. 1, since the buffer layer 5 contains a varistor layer constituting oxide as a main component,
Although the buffer layer is considered as the first ceramic layer and the intermediate laminate is composed of the buffer layer and the dielectric layer, the varistor layer 22 may be included in the intermediate laminate as the first ceramic layer. When the composition of the buffer layer is based on a dielectric layer, the buffer layer is considered as a second ceramic layer belonging to the capacitor section 3, while the varistor layer is considered as a first ceramic layer. hand,
An intermediate laminate may be constituted by the buffer layer and the varistor layer.

Other composite laminated parts Regarding the combination of the first ceramic layer and the second ceramic layer, the above-mentioned “varistor layer (buffer layer)”
-Dielectric layer ".

Dielectric layer-dielectric layer Dielectrics having different dielectric properties (for example, BaTiO ₃ , SrT
Electrostriction and the like can be suppressed by combining two types of dielectrics selected from iO ₃ , PbTiO _3, etc., but since these have different thermal properties and tend to generate internal stress, the present invention is effective. is there.

Dielectric layer-magnetic layer dielectric (for example, BaTiO ₃ , SrTiO ₃ , PbTiO
₃ ) and a magnetic material (eg, Ni—Cu—Zn ferrite) can be combined to form an LC filter. However, since these have different thermal properties, the present invention is effective.

Dielectric layer-resistor layer dielectric (for example, BaTiO ₃ , SrTiO ₃ , PbTiO
₃ ) and a resistor (for example, MnNiCr oxide) can be combined to form a filter, but since these have different thermal properties, the present invention is effective.

Dielectric layer-piezoelectric layer dielectric (for example, BaTiO ₃ , SrTiO ₃ , PbTiO
There is a possibility that new piezoelectric characteristics can be obtained by _3, etc.) and the combination of the piezoelectric element (e.g., PZT or the like), these are the thermal properties are different, the present invention is effective.

Dielectric layer-magnetic layer-varistor layer dielectric (for example, BaTiO ₃ , SrTiO ₃ , PbTiO
₃ ) and a magnetic material (for example, Ni-Cu-Zn ferrite,
Surge and noise can be absorbed by combining a planar (eg, hexagonal ferrite) and a varistor (eg, ZnO), but the present invention is effective because these have different thermal properties.

FIG. 2 is a perspective view showing a configuration example of an LCZ component in which the varistor portion 2, the capacitor portion 3, and the inductor portion 6 are stacked, and also shows a cross section perpendicular to the stacking direction. The equivalent circuit of this LCZ component is as shown in FIG. In this LCZ component, the varistor part 2 and the first intermediate laminate 10
1. The element body 10 is configured by laminating the capacitor part 3, the second intermediate laminate 102, and the inductor part 6. The varistor part 2 and the capacitor part 3 have the same configuration as the composite laminated component shown in FIG. The inductor section 6 has an internal conductor 61 and a ceramic magnetic layer 62, similarly to a normal ceramic chip inductor. A pair of terminal electrodes 41 and 42 connected to the varistor internal electrode and the capacitor internal electrode and an inductor external conductor 71 connected to the internal conductor 61 are formed on the side surface of the element body 10.

The first intermediate laminate 101 of the configuration example shown in FIG.
Includes a buffer layer having a composition based on the varistor layer composition as the one ceramic layer, and further includes a dielectric layer as the second ceramic layer, similarly to the composite laminated component shown in FIG. Then, the second intermediate laminate 102
Includes a dielectric layer as the first ceramic layer,
The second ceramic layer includes a ceramic magnetic layer. Note that the equivalent circuit is not limited to the LCZ component having the configuration shown in FIG.
The present invention can be applied to Z parts.

Dielectric layer-magnetic layer-resistor layer dielectric (for example, BaTiO ₃ , SrTiO ₃ , PbTiO
₃ ) and a magnetic material (for example, Ni-Cu-Zn ferrite,
Planar etc.) and resistor (MnNiCr oxide etc.)
Can be configured by combining
Since these have different thermal properties, the present invention is effective.

Dielectric layer-piezoelectric layer-magnetic layer dielectric (for example, BaTiO ₃ , SrTiO ₃ , PbTiO
₃ ), a piezoelectric body (such as PZT) and a magnetic body (for example, Ni-C
There is a possibility that new piezoelectric characteristics can be obtained by combining with u-Zn ferrite, planar, etc.), but since these have different thermal properties, the present invention is effective.

The present invention can be applied to, for example, a multilayer wiring board other than the above-described typical composite laminated parts.
Multilayer wiring boards with built-in capacitors and other functional elements
The present invention is effective because it has a configuration as a composite laminated component.

Manufacturing Method The multilayer ceramic composite component of the present invention can be manufactured in the same manner as a conventional multilayer chip component such as a multilayer ceramic capacitor. Hereinafter, a preferred method for manufacturing the composite laminated component of the present invention will be described by taking a varistor-capacitor composite laminated component as shown in FIG. 1 as an example.

In this method, first, a green chip is manufactured. In manufacturing a green chip, a sheet method or a printing method may be used as in the case of a conventional multilayer chip component. When the sheet method is used, first, raw material powders of a varistor material, a buffer layer material, a dielectric material, and an internal electrode material are prepared. Note that the calcined material of the starting material is used as the raw material powder of the dielectric material. Each raw material powder is kneaded with an organic vehicle to prepare a paste, and each paste excluding the internal electrode paste is formed into a sheet to form a green sheet. Next, after printing the paste for the internal electrode on the green sheet to be a layer adjacent to the internal electrode, the green sheets are laminated and pressure-bonded so as to have a predetermined structure. The obtained laminate is cut into a predetermined size to obtain a green chip. Next, after firing the green chip into an element body, printing or transferring terminal electrode paste is performed on the exposed surface of the internal electrode of the element body and firing, and further, if necessary, a plating film is formed on the terminal electrode surface. , To obtain an element.

As the raw material powder for the varistor layer, a composite oxide or a mixture of oxides can be used. In addition, various compounds that become a composite oxide or oxide upon firing, for example,
Carbonates, oxalates, nitrates, hydroxides, organometallic compounds and the like can be appropriately selected and used as a mixture. The same applies to the starting material of the dielectric layer. Glass powder is used as a glass material for the dielectric layer. The preferred average particle size of these raw material powders is about 0.1 to 5 μm for the main component of the varistor layer, about 0.1 to 3 μm for the subcomponent, and 0 μm for the dielectric layer. .1
About 3 μm, and about 1 to 10 μm for the dielectric layer made of glass powder. The varistor layer sub-component material may be added as a solution. The raw material powder for the buffer layer may be the same as the varistor layer raw material or the dielectric layer raw material depending on the composition of the buffer layer.

The organic vehicle is obtained by dissolving a binder in an organic solvent. The binder used for the organic vehicle is not particularly limited, and may be appropriately selected from various ordinary binders such as ethyl cellulose. In addition, the organic solvent to be used is not particularly limited, and may be appropriately selected from various organic solvents such as terpineol, butyl carbitol, acetone, and toluene according to a method to be used such as a printing method and a sheet method.

The calcination of the starting material for the dielectric is preferably performed in air at 1100 to 1300 ° C. for about 1 to 4 hours.

The firing conditions for the green chip may be optimal according to the varistor layer composition, the dielectric layer composition, and the internal electrode composition. The firing includes a temperature raising step, a temperature holding step, and a temperature lowering step. The firing conditions are preferably selected from the following ranges. The heating and cooling rates are 5
The temperature is preferably set to 0 to 400 ° C. The firing temperature, that is, the holding temperature in the temperature holding step is preferably 900
To 1400 ° C, more preferably 1100 to 1300 ° C. Firing time, that is, the duration of the temperature holding step,
Preferably it is 1 to 8 hours, more preferably 2 to 6 hours. The firing atmosphere may be any of an oxidizing atmosphere such as air and oxygen, and a non-oxidizing atmosphere such as nitrogen, but is preferably an atmosphere having a higher oxygen concentration than air. Specifically, in all the steps of firing, preferably at least 700 ° C.
The oxygen concentration in the above temperature range, more preferably in a temperature range of at least 500 ° C. or higher, is set higher than the oxygen concentration in the air. At this time, the oxygen concentration is preferably as high as possible, and it is most preferable that the atmosphere be 100% oxygen. Although a similar high oxygen concentration atmosphere may be used in a lower temperature region, it is preferable that the atmosphere in the lower temperature region be air for cost reduction.

Before firing, binder removal processing is usually performed. The binder removal treatment is preferably performed in air. The binder removal processing may be incorporated in the temperature raising step. Specifically, in a part of the heating step, the binder removal can be performed by stopping the heating or decreasing the heating rate.

The element body obtained by firing is preferably subjected to a polishing treatment such as barrel polishing. By this polishing process, warpage of the element body, bending or swelling of the end of the element body can be corrected, and the element body can be set to a predetermined size.

The firing conditions for the terminal electrode paste may be appropriately determined according to the terminal electrode composition. Usually, the firing atmosphere is air, the firing temperature is 500 to 1000 ° C., and the firing time is about 10 to 60 minutes. It is preferable that

When the above-mentioned plating film is formed on the surface of the terminal electrode, it is preferable to form a protective film on the surface of the element body except for the surface of the terminal electrode before plating. This protective film is for protecting the element body from the plating solution. Although the configuration of the protective film is not particularly limited, for example, a glass film can be used. This glass film can be formed by applying a paste containing a glass powder and an organic vehicle and firing the paste. After forming the plating film, it is not necessary to remove the protective film on the element surface.

[0080]

EXAMPLE A ceramic composite laminated part sample having the structure shown in FIG. 1 was produced by the following procedure.

First, pure water and a dispersant were placed in a monopot containing ZrO ₂ balls, and the following starting materials were further charged.

Varistor layer starting material 96.8% by weight of ZnO, 0.8% by weight of Co ₃ O _4, 2.0% by weight of Pr ₆ O _11, 0.2% by weight of Cr ₂ O _3, 0.2% by weight of Al ₂ O ₃ . 003% by weight, SrCO ₃ 0.2% by weight (SrO equivalent)

Next, mixing was performed by placing the pot on a turntable. The obtained mixture was transferred to an evaporating dish, dried in a drier, pulverized, an organic vehicle was added to the pulverized substance, and mixed and pulverized for 16 hours to obtain a paste. This paste was formed into a film by a doctor blade method to obtain a varistor layer green sheet.

A buffer layer green sheet was obtained in the same manner as in the production of the varistor layer green sheet except that the following starting materials were used.

Buffer layer starting material: ZnO 92.3% by weight, Co ₃ O ₄ 1.8% by weight, Pr ₆ O ₁₁ 4.9% by weight, Cr ₂ O ₃ 0.6% by weight, SrCO ₃ 0.4% by weight % (SrO conversion)

The following starting materials were prepared.

Starting material for dielectric layer: 66.3% by weight of La ₂ O ₃ , 33.5% by weight of TiO ₂ , 0.2% by weight of MnCO ₃ (in terms of MnO)

The starting materials were mixed and pulverized, dried, and calcined at 1200 ° C. for 2 hours. Glass powder was added to the obtained calcined product and mixed and pulverized. The content of the glass powder in the mixture was 1% by weight. A glass powder containing 59.70% by weight of ZnO, 21.72% by weight of B ₂ O _3, 9.64% by weight of SiO ₂ , and 8.94% by weight of CaO was used. Next, an organic vehicle was added and mixed and pulverized for further 16 hours to obtain a paste. This paste was formed into a film by a doctor blade method to obtain a dielectric layer green sheet.

Each green sheet was laminated and pressed according to the configuration shown in FIG. 1 to obtain a green laminate. In order to form the internal electrodes, a part of the varistor layer green sheets and the dielectric layer green sheets was laminated after printing an internal electrode paste containing Ag-Pd powder. Next, a green chip obtained by cutting the green laminate was fired to obtain an element body. The firing temperature (stabilizing part temperature) of the element body was 1150 ° C. At the time of firing, the temperature increase to 600 ° C. in the temperature raising step is performed in the air, and the subsequent temperature raising, all of the temperature holding step, and the temperature lowering step are carried out.
The temperature was lowered to 00 ° C. in an oxygen atmosphere, and the temperature was lowered to 600 ° C. or less in air. The firing time (duration of the temperature holding step) was 4 hours. The binder was removed by maintaining the temperature at 600 ° C. for 2 hours in the temperature raising step.

After firing, the varistor part 2 has a total thickness of 580 μm.
m, the thickness (distance between electrodes) of the varistor layer 22 is 100 μm,
The number of varistor layers having internal electrodes on both sides was 3, and the thickness of the buffer layer 5 was 80 μm. The total thickness of the capacitor part 3 is 410 μm, the thickness of the dielectric layer 32 is 10 μm,
The number of dielectric layers having internal electrodes on both sides was 10. The total thickness of the intermediate laminate is 270 μm, and the thickness of each layer constituting the intermediate laminate is 5a in FIG.
5b, 5c in the order of 60 μm, 40 μm, 20 μm,
In the dielectric layer, 75a, 32b, 32c in FIG.
μm, 50 μm, and 25 μm. In addition, the thickness of the internal electrode was 2-3 μm. Further, the thickness of the element diffusion region in the buffer layer 5 was 10 μm.

Next, the element body was barrel-polished together with a ZrO ₂ ball having a diameter of 2 mm.

Next, terminal electrodes (Ag) were formed on both sides of the element body where the internal electrodes were exposed by the Paloma method. Next, a glass protective film was formed on the surface of the element body except for the terminal electrode surface. Then, a plating film was formed on the surface of the terminal electrode by performing Ni plating and solder plating in this order, to obtain a multilayer composite function element.

FIG. 4 shows a scanning electron micrograph of a cross section of the element body of this sample. For comparison, a scanning electron micrograph of the element body of a sample manufactured in the same manner as the above sample except that the intermediate laminate was not provided is shown in FIG.
Shown in These photographs show the vicinity of the interface between the varistor part and the capacitor part in an enlarged manner. The slightly dark area is the varistor layer and the buffer layer, the slightly bright area is the dielectric layer, and the white line is Internal electrode. In FIG. 5 where the intermediate laminate is not provided, cracks occur from the buffer layer to the varistor layer. However, in FIG. 4 where the intermediate laminate is provided, no crack is observed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a ceramic composite laminated component of the present invention.

FIG. 2 is a perspective view showing a configuration example of a ceramic composite laminated component of the present invention.

FIGS. 3A and 3B are equivalent circuits of a ceramic composite laminated component.

FIG. 4 is a drawing substitute photograph showing the structure of a ceramic material, and is a scanning electron microscope photograph of an element body of the ceramic composite laminated part of the present invention.

FIG. 5 is a drawing substitute photograph showing the structure of a ceramic material, and is a scanning electron microscope photograph of an element body of a conventional ceramic composite laminated part.

[Explanation of symbols]

 2 Varistor part 21 Varistor internal electrode 22 Varistor layer 3 Capacitor part 31 Capacitor internal electrode 32, 32a, 32b, 32c Dielectric layer 41, 42 Terminal electrode 5, 5a, 5b, 5c Buffer layer 6 Inductor part 61 Internal conductor 62 Ceramic magnetism Body layer 71 Inductor outer conductor 10 Element main body 100 Intermediate laminate 101 First intermediate laminate 102 Second intermediate laminate

Claims (2)

[Claims] 1. A ceramic composite laminated part in which at least two ceramic parts are laminated, wherein two ceramic parts adjacent to each other via an intermediate laminated body are present, and the intermediate laminated body is formed of the two ceramic parts. One ceramic layer made of a ceramic material contained in one of the two ceramic parts and the other ceramic layer made of a ceramic material contained in the other of the two ceramic parts are alternately laminated in a total of three or more layers. When there are a plurality of ceramic layers, the one closer to the one ceramic part of the one ceramic layer is thicker, and when there are a plurality of the other ceramic layers, the other ceramic part of the other ceramic layer Ceramic composite laminated parts that are thicker as they are closer to. 2. The ceramic composite laminated part according to claim 1, wherein the two ceramic parts adjacent to each other via the intermediate laminated body are a ceramic part having a varistor function and a ceramic part having a capacitor function.