JP2011199200A - Laminated composite electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated composite electronic component superior in denseness and shape holding properties of an intermediate bonding layer and reducing deterioration, especially in the characteristics of a varistor element portion.SOLUTION: The laminated composite electronic component includes the varistor element portion 20, a ferrite element portion 30, and the intermediate bonding layer 40, and the intermediate bonding layer 40 is substantially composed of a glass composition containing 30-60 wt.% SiO, 0-20 wt.% ZnO, 0-20 wt.% AlO, 0-5 wt.% BO, 30-50 wt.% alkali earth metal oxide, and 0-1 wt.% alkali metal oxide.

Description

  The present invention relates to a multilayer composite electronic component in which a plurality of element parts such as a varistor element part and a ferrite element part are incorporated.

  In electronic parts such as computer equipment, chip inductors, chip capacitors, chip varistors are placed in the input / output section of the circuit board and in the middle of the circuit so that the equipment itself does not generate noise and does not allow noise to enter the equipment from outside. Etc. are incorporated.

  However, when these many chip parts are mounted on a circuit board, there is a problem that these chip parts occupy a large board area and the mounting space is expanded. In addition, an increase in the number of parts causes a problem of cost increase.

  Therefore, attempts have been made to make a laminated electronic component by integrally sintering the element portions constituting each chip component while being bonded to each other, thereby reducing the size of the component and reducing the mounting space. The laminated electronic component incorporates a conductor electrode therein, and in that case, in order to reduce the conductor loss of the device, it is preferable to use a high conductivity electrode material. However, Ag or Cu having high conductivity has a low melting point and cannot be used under the firing conditions of ceramics exceeding 1000 ° C. Therefore, a technique of adding an oxide or glass composition having a low melting point as a sintering aid to the element portion having a high sintering temperature is used so that it can be sintered at a low temperature. Low-temperature firing is desirable from the viewpoint of energy costs and high melting point Pd and Pt, and therefore from the viewpoint of electrode material costs.

  However, element portions having different functions are made of different materials, and peeling, cracking or deformation at the interface of the joints becomes a problem. Furthermore, it is necessary to suppress fluctuations in characteristics due to diffusion of components from each element part at the interface of the joint part. In particular, a sintering aid having a low melting point has a problem that it easily diffuses and easily causes component diffusion.

  In order to solve the problem of component diffusion, for example, Patent Document 1 proposes forming an intermediate bonding layer including a specific glass layer at the bonding portion between the capacitor element portion and the ferrite element portion. In Patent Document 1, it is described that a characteristic variation due to diffusion of components from each element portion can be suppressed by forming a specific glass layer.

  However, when the intermediate bonding layer formed of the glass layer described in Patent Document 1 is used for a multilayer composite electronic component including a varistor element portion and a ferrite element portion, there are the following problems. That is, in the intermediate bonding layer composed of the glass layer described in Patent Document 1, the amount of alkali metal oxide is too large and the amount of bismuth oxide is too large. In particular, there is a problem that the characteristics of the varistor element portion deteriorate.

  In the case of varistor materials composed of a polycrystalline material obtained by sintering a semiconductor material, the state of grain boundaries that express varistor characteristics is remarkably reflected in the characteristics. The diffusion and inflow (outflow) of the agent (including the agent) are likely to cause characteristic fluctuations.

JP 2001-244140 A

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a multilayer composite electronic component that is excellent in denseness and shape retention of an intermediate bonding layer, and in particular, has little deterioration in characteristics of a varistor element portion. .

In order to achieve the above object, a multilayer composite electronic component according to the present invention includes:
A laminate having a varistor element portion having a varistor layer and an internal electrode layer, a ferrite element portion having a ferrite layer and an internal conductor layer, and an intermediate bonding layer interposed to bond both of the element portions. Type composite electronic component,
The intermediate bonding layer is composed of a glass layer,
The glass layer is
SiO _2: 30~60% by weight,
ZnO: 0 to 20% by weight,
Al ₂ O ₃ : 0 to 20% by weight,
B ₂ O ₃ : 0 to 5% by weight,
It is substantially composed of a glass composition containing an alkaline earth metal oxide: 30 to 50% by weight and an alkali metal oxide: 0 to 1% by weight. However, preferably, bismuth oxide is substantially not included. Note that “substantially free of bismuth oxide” means 0.2% by weight or less.

  In the multilayer composite electronic component according to the present invention, since the intermediate bonding layer is made of a specific glass composition, the denseness and shape retention of the intermediate bonding layer are improved, and interdiffusion between the element portions is performed. In particular, the characteristic deterioration of the varistor element portion is small. In addition, it is possible to realize a multilayer composite electronic component having excellent adhesion without causing deformation or cracks in the intermediate bonding layer that is a bonding interface between the element portions.

  Preferably, the glass layer includes a filler. Examples of the filler include, but are not limited to, nickel oxide, zirconium oxide, zinc oxide, aluminum oxide, titanium oxide, strontium titanate, zirconium silicate, magnesium silicate, quartz silica, and fused silica. The ferrite layer is Ni. In the case of containing nickel, nickel oxide is preferably used as the filler.

  Preferably, the filler is less than 50% by volume, more preferably 20 to 35% by volume, based on the total volume of the glass composition and the filler.

  By including a predetermined amount of filler, the sintering behavior (thermal shrinkage behavior) and thermal expansion coefficient of the intermediate bonding layer can be adjusted, and the adhesion between the varistor element portion and the ferrite element portion can be further improved. .

  The glass layer may be formed of either amorphous glass or crystalline glass, but amorphous glass is preferred when a filler is included. In the case of amorphous glass, a relatively large amount of filler can be contained.

  The glass layer constituting the intermediate bonding layer may be a single layer or multiple layers. When the glass layer is a multilayer, a plurality of glass layers having different physical property values from the varistor element portion toward the ferrite element portion may be used.

  Moreover, the glass composition contained in the glass layer may be a mixture of a plurality of glass compositions instead of a single glass composition. By changing the mixing ratio of the plurality of glass compositions, the sintering behavior and the thermal expansion coefficient of the intermediate bonding layer can be adjusted, and the adhesion between the varistor element portion and the ferrite element portion can be further improved.

FIG. 1 is a perspective view of a multilayer composite electronic component according to an embodiment of the present invention. FIG. 2 is a schematic sectional view taken along line II-II in FIG. FIG. 3 is an exploded perspective view of the multilayer composite electronic component shown in FIGS. 1 and 2. FIG. 4 is a graph showing the relationship between the temperature of the intermediate bonding layer and the shrinkage rate in the multilayer composite electronic component.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
As shown in FIG. 1, the multilayer composite electronic component 2 according to the present embodiment has a substantially rectangular parallelepiped ceramic chip 4, and a pair of external ends are disposed at both ends in the longitudinal direction (X axis) of the chip 4. Electrodes 6 and 8 are formed. Further, a pair of intermediates are provided on both side surfaces in the short direction (Y axis) of the chip 4 positioned at the intermediate position in the longitudinal direction (X axis) of the chip 4 positioned between these end external electrodes 6 and 8. An external electrode 10 is formed. These external electrodes 6, 8, 10 are insulated from each other on the outer surface of the chip 4.

  As shown in FIGS. 2 and 3, a varistor element portion 20 and a ferrite element portion 30 are formed in the chip 4 along the stacking direction (Z-axis), and these element portions 20 and 30 are formed. Are bonded by the intermediate bonding layer 40. In the present embodiment, the varistor element unit 20 includes a first internal electrode layer 24, a varistor layer 22, and a second internal electrode layer 25, which are alternately stacked.

  The lead part 24a of the first internal electrode layer 24 shown in FIG. 3 is connected to the end external electrode 6 shown in FIG. 1, and the pair of lead parts 25a drawn in the Y-axis direction in the second internal electrode 25 are: The intermediate external electrodes 10 and 10 shown in FIG.

  In the present embodiment, as shown in FIG. 3, the inductor section 30 has a structure in which ferrite layers 32 and internal conductor layers 34 to 39 are alternately stacked. A through-hole electrode 33 is formed in the ferrite layer 32 sandwiched between the inner conductor layers 34 to 39, and the inner conductor layers 34 to 39 are connected by a predetermined coil pattern to form a ferrite element. Of the inner conductor layers 34 to 39, a pair of lead portions 34a are formed in the inner conductor layer 34 located at the end in the stacking direction (Z-axis), and each lead portion 34a is shown in FIG. The end external electrodes 6 and 8 are connected respectively.

  Accordingly, the multilayer composite electronic component 2 shown in FIGS. 1 to 3 has a structure in which the varistor element portion 20 and the ferrite element portion 30 are built in a single chip component. Moreover, as shown in FIG. 2, the varistor element portion 20 and the ferrite element portion 30 are separated by an intermediate bonding layer 40 in the multilayer composite electronic component 2.

  The varistor layer 22 in the varistor element portion 20 is not particularly limited as long as it is a material that exhibits voltage nonlinearity in which a resistance value changes nonlinearly with respect to a voltage applied between the internal electrode layers 24 and 25. Examples include varistor materials mainly composed of zinc oxide, tin oxide, titanium oxide, strontium titanate, barium titanate and other oxide semiconductor materials, but preferably varistor materials mainly composed of zinc oxide. Composed. The varistor material containing zinc oxide as a main component contains 95 to 98 mol% of ZnO as a main component, and other additive components include bismuth oxide, cobalt oxide, tin oxide, manganese oxide, and aluminum oxide. And rare earth oxides such as chromium oxide, antimony oxide, boron oxide, calcium oxide, silicon oxide, and Pr.

  The internal electrode layers 24 and 25 in the varistor element portion 20 are made of, for example, Ag, Cu, Au, Pt, Pd, or an alloy thereof.

  The thickness of the varistor layer 22 is not particularly limited, but is preferably 100 to 400 μm. The thicknesses of the internal electrode layers 24 and 25 are not particularly limited, but are preferably 5 to 20 μm.

  The ferrite layer 32 in the ferrite element portion 30 is not particularly limited, but is composed of, for example, Ni—Cu—Zn based magnetic ferrite or nonmagnetic Zn based ferrite.

Examples of the Ni—Cu—Zn based magnetic ferrite include, for example, iron oxide 40 to 50 mol% in terms of Fe ₂ O ₃ , nickel oxide 5 to 35 mol% in terms of NiO, and zinc oxide 1 to 35 in terms of ZnO. What contains 1-15 mol% of mol% and copper oxide in conversion of CuO is illustrated. Such a Ni—Cu—Zn based ferrite may have a composition in which a part of Zn or Fe is substituted with at least one of Mg and Mn. Furthermore, as a component to be added, SiO ₂ , CaCO ₃ , ZrO ₂ , SnO ₂ , TiO ₂ , MoO ₃ , Bi ₂ O ₃ , WO ₃ , CoO and the like may be contained in a total of 10% by weight or less.

Examples of the nonmagnetic Zn-based ferrite include those in which iron oxide is contained in an amount of 40 to 50 mol% in terms of Fe ₂ O ₃ and zinc oxide is contained in the remaining mol% in terms of ZnO. Such a non-magnetic Zn-based ferrite may have a composition in which a part of Zn or Fe is substituted with at least one of Ni, Mg, Mn, and Cu. In this case, the substitution of Ni, Mg, Mn and Cu is usually within 10 mol%. Furthermore, as an additional component, SiO ₂ , CaCO ₃ , ZrO ₂ , SnO ₂ , TiO ₂ , MoO ₃ , Bi ₂ O ₃ , WO ₃ , CoO and the like may be contained in a total of 10% by weight or less.

  The inner conductor layers 34 to 39 are made of, for example, Ag, Cu, Au, Pt, Pd, or an alloy thereof.

  The thickness of the ferrite layer 32 is not particularly limited, but is preferably 200 to 500 μm. The thickness of each of the inner conductor layers 34 to 39 is not particularly limited, but is preferably 5 to 20 μm.

  In the present embodiment, the intermediate bonding layer 40 is composed of a glass layer, and the glass composition constituting the glass layer may be amorphous or crystalline. However, in the case of being amorphous, compatibility with a filler described later is good, and a relatively large amount of filler can be contained.

The glass layer constituting the intermediate bonding layer 40 contains 30 to 60% by weight, preferably 40 to 55% by weight of SiO ₂ . If the amount of SiO ₂ is too small, the denseness and shape retention of the intermediate bonding layer 40 are lowered, and the effect of suppressing mutual diffusion of each component between the element portions 20 and 30 is lowered. If there is too much SiO ₂ , vitrification tends to be difficult unless a large amount of alkali metal or boron (B) is added, the denseness is lowered, and the mutual diffusion of each component between the element parts 20 and 30 is suppressed. There is a tendency for the effect to be reduced.

  Further, the glass layer contains 0 to 20% by weight, preferably 10% by weight or less, and preferably substantially free of ZnO. Inclusion of ZnO improves the durability of the intermediate bonding layer 40. However, if there is too much ZnO, the denseness decreases and the effect of suppressing the mutual diffusion of each component between the element portions 20 and 30 decreases. Tend to.

Further, the glass layer contains Al ₂ O _{3 in an amount} of 0 to 20% by weight, preferably 10% by weight or less, but may not be substantially contained. By including Al ₂ O ₃ , the durability of the intermediate bonding layer 40 is improved. However, if the amount is too large, the bonding characteristics between the element portions 20 and 30 are deteriorated and the effect of suppressing mutual diffusion is reduced. There is a tendency.

The glass layer contains B ₂ O _{3 in an amount} of 0 to 5% by weight, preferably 0 to 4.8% by weight, and more preferably 0 to 2% by weight. By including B ₂ O ₃ , SiO ₂ is easily melted, but if too much, the bonding characteristics between the element portions 20 and 30 deteriorate, and the shape retention of the intermediate bonding layer 40 deteriorates, The effect of suppressing interdiffusion tends to decrease.

  Further, the glass layer contains an alkaline earth metal oxide in an amount of 30 to 50% by weight, preferably 35 to 45% by weight. By including a predetermined amount or more of the alkaline earth metal oxide, the durability and shape retention of the glass are improved, but if it is too much, it tends to not vitrify. The alkaline earth metal is not particularly limited, but Mg, Ca, Sr, and Ba are preferably used, for example.

Further, the glass layer contains 0 to 1 wt%, preferably 0 to 0.5 wt%, more preferably 0 to 0.3 wt% of the alkali metal oxide, but it may not contain substantially. By including an alkali metal oxide, SiO ₂ is easily melted, but if it is too much, the durability of the glass tends to decrease. Although it does not specifically limit as an alkali metal, For example, Li, Na, K is used preferably, Especially preferably, Li is used.

  In the present embodiment, the glass layer may contain other metal oxides. Examples of other metal oxides include titanium oxide, zirconia oxide, tin oxide, bismuth oxide, and oxides of lanthanum series elements. The other oxide is preferably 10% by weight or less, more preferably 8% by weight or less, and particularly preferably 7% by weight or less. However, in this embodiment, preferably, bismuth oxide is not substantially included. “Substantially free of bismuth oxide” means 0.2% by weight or less.

  In the present embodiment, the intermediate bonding layer 40 made of such a glass layer may contain a filler. Examples of the filler include, but are not limited to, nickel oxide, zirconium oxide, zinc oxide, aluminum oxide, titanium oxide, strontium titanate, zirconium silicate, magnesium silicate, quartz silica, and fused silica. The ferrite layer is Ni. In the case of containing nickel, nickel oxide is preferably used as the filler.

  Preferably, the filler is contained in an amount of 0 to less than 50% by volume, more preferably 20 to 35% by volume, based on the total volume of the glass composition and the filler. The filler contained in a glass layer does not necessarily need to be one type, and multiple types may be sufficient as it.

  By including the filler in a predetermined amount, the sintering behavior and the thermal expansion coefficient of the intermediate bonding layer 40 can be adjusted, and the adhesion between the varistor element portion and the ferrite element portion can be further improved.

  The thickness of the intermediate bonding layer 40 is desirably as thin as possible in order to make the composite sintered product compact, and the thickness is 60 to 300 μm, preferably 60 to 180 μm.

  In the present embodiment, the glass layer constituting the intermediate bonding layer 40 has a softening point higher than the sintering (shrinkage) start temperature of the varistor layer 22 and the ferrite layer 32 that are in contact with the intermediate bonding layer 40, preferably Is 800 ° C. or higher. Moreover, it is preferable that a glass layer has the thermal property which sinters (individualizes) at 900 degrees C or less, and it is preferable that the porosity of the glass layer after baking is 10 volume% or less. The thermal contraction rate of the intermediate bonding layer 40 itself is preferably 16.0 ± 3.0% at a firing temperature of 900 ° C.

  Further, in the glass layer constituting the intermediate bonding layer 40, the difference in temperature (TMA evaluation) at which the shrinkage rate becomes the same after the start of shrinkage during firing with respect to the material of the varistor layer 22 or the ferrite layer 32 is 40 ° C. Is preferably within. Further, the difference in thermal expansion coefficient at each temperature between room temperature and 700 ° C. is preferably within 2 ppm / K, more preferably between the glass layer constituting the intermediate bonding layer 40 and the varistor layer 22 or the ferrite layer 32. Within 1 ppm / K.

  The multilayer composite electronic component 2 shown in FIGS. 1 to 3 is manufactured as follows, for example. That is, as shown in FIG. 3, first, a green sheet to be the varistor layer 22, a green sheet to be the ferrite layer 32, and a green sheet to be the intermediate bonding layer 40 are manufactured. Each green sheet is formed by a thick film forming method such as a doctor blade method using a slurry (or paint, hereinafter the same) in which components having the above-described composition are dispersed after firing.

  Next, electrode paste films to be the internal electrode layers 24 and 25 are respectively formed on the surface of the green sheet to be the varistor layer 22 by a printing method or the like. In addition, the inner conductor layers 34 to 39 are formed on the surface of the green sheet to be the ferrite layer 32, and the through-hole electrode 33 is formed.

  The green sheet used as the intermediate | middle joining layer 40 is formed with the slurry containing the component used as the glass composition mentioned above after baking, and may be single or may be plural. When there are a plurality of green sheets constituting the intermediate bonding layer 40, the composition may be changed without constituting the same glass composition.

  For example, the green sheet of the intermediate bonding layer 40 close to the varistor element portion 20 may have a glass composition with excellent adhesion to the green sheet constituting the varistor layer 22. Further, the green sheet of the intermediate bonding layer 40 close to the ferrite element portion 30 may have a glass composition excellent in adhesion with the green sheet constituting the ferrite layer 32. And the green sheet of the intermediate | middle joining layer 40 located between them may be made into the glass composition of those intermediate | middle.

  The green sheet that constitutes the intermediate bonding layer 40 may contain glass particles made of one kind of glass composition, but may contain glass particles made of two or more kinds of glass compositions. . By changing the mixing ratio of multiple types of glass compositions, the sintering behavior and thermal expansion coefficient of the intermediate bonding layer can be adjusted, and the adhesion between the varistor element part and the ferrite element part can be further improved. .

  In addition, the particle size of the glass particle contained in a green sheet is although it does not specifically limit, Preferably it is 0.5-2.0 micrometers. Moreover, you may add a filler to a green sheet with a glass particle. The kind and addition ratio of the filler are as described above. The filler may be granular, but is not necessarily granular, and may be flat or fibrous. The representative length of the filler (particle size in the case of grains, length in the case of fibers, maximum length in the case of other shapes) is preferably 0.25 to 4.0 μm, and glass particles It is 0.5 to 2 times the particle size of.

  Next, these green sheets are pressure-laminated to form a laminate, and the green chip after cutting is subjected to a binder removal treatment as necessary, followed by a firing treatment. The firing temperature is preferably 850 to 950 ° C.

  Thereafter, for example, an external electrode paste mainly composed of silver is applied in a pattern of the external electrodes 6, 8, and 10 shown in FIG. 1, and these are baked at a predetermined temperature (for example, 600 to 700 ° C.). External electrodes 6, 8, and 10 are formed by performing electroplating. As electroplating, Ni and Sn, Cu and Ni and Sn, Ni and Au, Ni and Pd and Au, Ni and Pb and Ag, Ni and Ag, or the like can be used. In this way, the multilayer composite electronic component 2 shown in FIG. 1 is obtained.

  In the multilayer composite electronic component 2 according to this embodiment, since the intermediate bonding layer 40 is made of a specific glass composition, the intermediate bonding layer 40 that is the bonding interface between the element portions 20 and 30 is deformed. In addition, it is possible to realize the multilayer composite electronic component 2 having excellent adhesion without causing cracks and cracks.

  Further, in the multilayer composite electronic component 2 according to the present embodiment, the intermediate bonding layer 40 is made of a specific glass composition, and does not contain a liquid phase component that is too fluid in the sintering process. For this reason, the denseness and shape retention of the intermediate bonding layer 40 are improved. Therefore, in the present embodiment, the intermediate bonding layer 40 suppresses mutual diffusion between the element portions 20 and 30, and in particular, the characteristic deterioration of the varistor element portion 20 is small.

In general, the varistor layer 22 of the varistor element portion 20 includes a component that becomes a liquid phase in the firing process, such as a low-melting glass or a low-melting oxide (for example, B ₂ O ₃ , Bi ₂ O ₃ ). When it is 1.0% by weight or more based on the entire varistor layer 22, mutual diffusion with the ferrite element portion 30 is likely to occur. As the low melting point glass used for the varistor layer, for example, glass containing 20% by weight or more of B ₂ O ₃ and a melting point of 700 ° C. or more, or glass containing 70% by weight or more of Bi ₂ O ₃ and a melting point of 700 ° C. or more. Is exemplified. When such a low-melting glass or a low-melting oxide, particularly an oxide such as Bi ₂ O ₃ is included, mutual diffusion with the ferrite element portion 30 is likely to occur.

In the present embodiment, even when the varistor layer 22 includes such a low-melting glass or low-melting oxide, particularly an oxide such as Bi ₂ O ₃ , the intermediate bonding layer 40 is made of a specific glass composition. For this reason, mutual diffusion between the element units 20 and 30 is suppressed, and the characteristics of the varistor element unit 20 are not deteriorated.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.
For example, the internal electrode patterns of the varistor element portion 20 and the ferrite element portion 30 in the multilayer composite electronic component are not limited to the illustrated embodiment, and can be variously modified.

Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.
Example 1 and Comparative Example 1
[Varistor layer of varistor element]

In order to form the varistor layer 22 of the varistor element part 20 shown in FIG. 3, the main component ZnO is 97 mol%, Co ₃ O ₄ is 2.4 mol%, Bi ₂ O ₃ is 0.3 mol%, Pr ₆ O ₁₁ 0.2 mol%, and CaCO ₃ were weighed so that 0.1 mol%. This weighed product was dispersed in a solvent together with an organic binder to form a slurry.

Thereafter, a green sheet for a varistor having a thickness of 30 μm was produced from this slurry by a doctor blade method.
[Ferrite layer of ferrite element]

In order to form the ferrite layer 32 of the ferrite element portion 30 shown in FIG. 3, the Fe ₂ O ₃ was weighed so as to be 49 mol%, NiO 20 mol%, CuO 11 mol%, and ZnO 20 mol%. . Pure water was added to this weighed product and mixed with a ball mill for 24 hours to form a slurry. The slurry was filtered, dried and granulated, and calcined at 700 ° C. for 2 hours. Next, pure water was added to the calcined product and further pulverized.

Next, the obtained fine powder was filtered and dried, and then dispersed in a solvent together with an organic binder to form a slurry. Thereafter, a ferrite green sheet having a thickness of 20 μm was produced from this slurry by a doctor blade method.
(Intermediate bonding layer)

  A green sheet to be the intermediate bonding layer 40 shown in FIG. 3 was prepared. The green sheet contained glass particles made of a glass composition having the compositions of sample numbers 1 to 10 shown in Table 1. Sample numbers 2, 3, 4, and 10 are amorphous glass particles, and sample numbers 1, 5, 6, 7, 8, and 9 are crystalline glass.

In Table 1, the blank indicates that each component is not substantially contained. In addition, the range which does not contain substantially differs for each component. For example, in the case of alkali metal, B ₂ O ₃ , 0.1% by weight or less is set as a range not substantially containing ZnO, Al ₂ O. _In the case of ₃ , 0.5% by weight or less is set to a range not substantially containing.

The average particle diameter of the glass particles contained in the green sheet to be the intermediate bonding layer 40 was 1.2 μm. The green sheet serving as the intermediate bonding layer 40 had a thickness of 30 μm, and the green bonding sheet 40 was formed by stacking three green sheets.
[Lamination and firing]

  8 sheets of 30 μm-thick varistor green sheets composed of the above composition, 3 sheets of 30 μm-thick intermediate bonding layer green sheets having the glass composition shown in Table 1, and composed of the above composition The 18 ferrite layers having a thickness of 20 μm were pressure-bonded by applying a pressure of 100 MPa in the laminating direction to form a laminate. Next, this laminate was cut to a predetermined size to obtain a green chip.

Thereafter, the green chip was fired at 900 ° C. for 2 hours to prepare a sintered body sample. Thereafter, external electrodes 6, 8, and 10 shown in FIG. 1 were formed on the outer surface of the sintered body sample. Note that the internal electrode layers 24 and 25 and the internal conductors 34 to 39 shown in FIG. 3 were formed by applying a predetermined conductive paste in advance before forming the laminated body.
[Measurement and evaluation]

The composite multilayer electronic component sample thus formed was measured and evaluated for the denseness and shape retention of the intermediate joint, the presence or absence of cracks and peeling, and the varistor voltage V _{1 mA} of the varistor element.

  The denseness of the intermediate joint was evaluated qualitatively by FE-SEM observation. The case where there were almost no vacancies was rated as ◎, the case where there were few vacancies was marked as ◯, and the case where there were many vacancies was marked as x.

  The shape retention of the intermediate joint was evaluated qualitatively by observing the shape of the composite multilayer electronic component after sintering. The case where the intermediate joint between the varistor and ferrite maintains the rectangular shape of the green chip is marked with ◎, and the shape is maintained, but the edge is rounded with ○, foam, glass When the deformation | transformation by melting or the outflow from a joining interface was seen, it was set as x.

  For the presence or absence of cracks or deformation, the appearance of 20 samples of each sample number was observed, and the case where the number of samples in which cracks or peeling was observed was 1 or less was judged as ◎, and the case of 2 to 4 ○ was judged, and the case of 5 or more was judged as x.

Furthermore, the varistor voltage V _{1 mA} of the varistor element portion was evaluated as follows. That is, the varistor voltage when a current flows through 1mA in the varistor element, in terms of the value of the per varistor thickness 1 mm, it is defined as V _1mA, about 20 samples of each sample number, the average of the varistor voltage V _1mA The average value thereof was determined as junction V _{1 mA} . Samples of a single varistor element were prepared under the same conditions except that the multilayer composite electronic component was not used, and the average of the varistor voltage V _{1 mA} was obtained with the same number of samples, and the average value was defined as a single V _{1 mA} .

Then, ΔV _{1 mA} = junction V _{1 mA} / unit V _{1 mA} was determined as the rate of change of the varistor voltage. The closer ΔV _{1 mA} is to 1, the smaller the change in varistor characteristics. In Table 1, when ΔV _{1 mA} is 0.85 or more and 1.15 or less, preferably 0.87 or more and 1.13 or less, more preferably 0.9 or more and less than 1.1, the change in varistor characteristics is small. Is shown.

  As shown in Table 1, compared to Comparative Example 1 of Sample Nos. 7 to 10, in Example 1 of Sample Nos. 1 to 6, the intermediate bonding layer 40 is composed of a glass layer having a specific glass composition. In addition, it was confirmed that a multilayer composite electronic component having excellent adhesion without causing deformation and cracks can be realized. Further, compared with Comparative Example 1, in Example 1, since the intermediate bonding layer 40 is made of a specific glass composition, the density and shape retention of the intermediate bonding layer 40 are improved, and the element It was confirmed that interdiffusion between the portions 20 and 30 was suppressed, and in particular, the characteristic deterioration of the varistor element portion 20 was small.

  In addition, it is considered that the sample of Sample No. 7 has a small amount of silicon oxide and a large amount of boron oxide, so that the shape retaining property is poor and a multilayer composite electronic component that can be evaluated for characteristics cannot be obtained. Further, in the sample of Sample No. 8, since a large amount of zinc oxide is contained, it is considered that the denseness is poor, the deterioration of the varistor characteristics is large, and cracks and peeling are observed.

Further, in the sample of sample number 9, since the amount of silicon oxide is small and the amount of aluminum oxide is large, it is considered that cracks and peeling are large and the deterioration of varistor characteristics is large. Furthermore, in the sample of Sample No. 10, a large amount of silicon oxide is vitrified with boron oxide, but the shape-retaining property is poor, and cracks and delamination are seen. It is thought that it was not obtained.
Example 2, Reference Examples 1 and 2

  In Example 2, together with glass particles having the compositions of sample numbers 1 to 6 shown in Table 1, a slurry in which the filler shown in Table 2 was dispersed at a ratio of 25% by volume of filler to 75% by volume of glass particles was formed. Then, samples 11 to 28 were manufactured as green chips with only the intermediate bonding material, and the shrinkage behavior of the green chips and the thermal expansion coefficient of the sintered body were measured. The results are shown in Table 2.

  The thermal expansion coefficient shown in Table 2 is a thermal expansion coefficient (ppm / K) at 700 ° C. based on room temperature, calculated from the linear expansion behavior of the sintered body. In addition, the shrinkage temperature shown in Table 2 is measured when the shrinkage behavior is measured by TMA. For example, as shown in FIG. 4, the temperature in the case of 5% shrinkage and the temperature in the case of 10% shrinkage Asked.

  In Reference Example 1, the thermal expansion coefficient and shrinkage temperature of the single varistor element unit in Example 2 were determined in the same manner as in Example 2. In Reference Example 2, the thermal expansion coefficient and shrinkage temperature in the ferrite element portion were determined in the same manner as in Example 2.

As shown in Table 2, in Example 2, the physical properties close to each of the varistor element part shown in Reference Example 1 or the ferrite element part shown in Reference Example 2 by changing the combination of the glass composition and the filler. It was confirmed that (thermal expansion coefficient, shrinkage temperature) and intermediate physical properties can be set.
Example 3 and Comparative Example 2

  In Example 3, it was carried out except that one or more kinds of glass particles having the compositions of sample numbers 1 to 6 shown in Table 1 were added, one or more kinds of fillers shown in Table 3 were added, and the addition ratio was changed. As in Example 2, samples 31 to 40 were manufactured as green chips with only an intermediate bonding material, and the thermal expansion coefficient and the shrinkage temperature were measured. The results are shown in Table 3. In Table 3, the denseness evaluated in the same manner as in Example 1 is also shown. In Table 3, Reference Examples 1 and 2 of Sample Nos. 29 and 30 are also shown together with Example 2 of Sample Nos. 13, 17, and 23 shown in Table 2.

  As shown in Table 3, in Sample Nos. 31, 34 and 38 according to Comparative Example 2, the amount of filler added was too large as 50% by volume, the denseness of the intermediate bonding material was lowered, and the thermal expansion coefficient and shrinkage temperature were reduced. A part of could not be measured. Therefore, when a filler is included, it is preferably less than 50% by volume.

  As shown in Table 3, when the addition amount of the filler is less than 50, preferably 40% by volume or less, the type and addition amount of the filler are changed to change the varistor element portion shown in Reference Example 1 or the reference. It was confirmed that the physical properties (thermal expansion coefficient, shrinkage temperature) close to each of the ferrite element portions shown in Example 2 and intermediate physical properties thereof can be set.

  As shown in Example 3 of Sample No. 35 in Table 3, it was confirmed that the heat shrinkage characteristics could be adjusted by adding two or more kinds of fillers. Moreover, as shown in Example 3 of Sample Nos. 39 and 40 in Table 3, by including two or more kinds of glass compositions, intermediate heat shrinkage characteristics of each glass composition can be obtained, and the heat shrinkage characteristics are adjusted. I can confirm that I can do it.

2 ... Stacked composite electronic components,
4 ... Ceramic chip 6, 8 ... End external electrode 10 ... Intermediate external electrode 20 ... Varistor element part 22 ... Varistor layer 24, 25 ... Internal electrode layer 30 ... Ferrite element part 32 ... Ferrite layer 34-39 ... Internal conductor layer 40 … Intermediate bonding layer

Claims (3)

A laminate having a varistor element portion having a varistor layer and an internal electrode layer, a ferrite element portion having a ferrite layer and an internal conductor layer, and an intermediate bonding layer interposed to bond both of the element portions. Type composite electronic component,
The intermediate bonding layer is composed of a glass layer,
The glass layer is
SiO _2: 30~60% by weight,
ZnO: 0 to 20% by weight,
Al ₂ O ₃ : 0 to 20% by weight,
B ₂ O ₃ : 0 to 5% by weight,
A multilayer composite electronic component comprising substantially a glass composition containing an alkaline earth metal oxide: 30 to 50% by weight and an alkali metal oxide: 0 to 1% by weight.   The multilayer composite electronic component according to claim 1, comprising less than 50% by volume of filler with respect to the total volume of the glass composition and filler.   The multilayer composite electronic component according to claim 2, wherein the filler is nickel oxide.

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