JP6922701B2 - Dielectric compositions, electronic components and laminated electronic components - Google Patents

Description

The present invention relates to dielectric compositions, electronic components and laminated electronic components.

Multilayer ceramic capacitors are installed in many electronic devices due to their high reliability and low cost.

In recent years, for example, in applications such as multilayer ceramic capacitors used for in-vehicle electronic components and multilayer ceramic capacitors mounted on electronic circuits using power semiconductors whose substrates are SiC, GaN, etc., the temperature is -55 ° C to 250 ° C. It is required that the rate of change in capacitance is small in a wide range of temperatures up to the vicinity.

Patent Document 1 discloses a dielectric ceramic composition that exhibits a sufficient dielectric constant and can obtain a stable capacitance temperature characteristic and a high resistivity ρ even at a high temperature of about 175 ° C. The dielectric ceramic composition, the composition formula _{(1-a) (K 1} -x Na x) (Sr 1-y-z Ba y Ca z) 2 Nb 5 O 15 -a (Ba 1-b Ca b) It _{contains a mixed crystal system of a tungsten bronze structural compound represented by TiO 3} and a perovskite structural compound as a main component, and contains 0.1 to 40 mol parts of a sub-component with respect to 100 mol parts of the main component. It is characterized by doing.

Patent Document 2 describes a dielectric porcelain composition containing a main component containing barium titanate, BaZrO ₃ , Mg oxide, rare earth element, Al oxide and the like, and sub-components of Si, Li, Ge and B. Is disclosed. Since the dielectric porcelain composition has the above-mentioned characteristics, it has an excellent high-temperature load life and can be suitably used for medium- and high-pressure applications.

However, in the dielectric ceramic composition described in Patent Document 1, the temperature change of the capacitance becomes large when the upper limit of the temperature range is extended to 250 ° C. Further, since the main component of the dielectric porcelain composition described in Patent Document 2 is barium titanate, the relative permittivity sharply decreases in a temperature range exceeding 150 ° C., and the capacitance decreases. ..

International Publication No. 2008/155945 Japanese Unexamined Patent Publication No. 2008-162830

The present invention provides a dielectric composition having a relatively high relative permittivity in a high temperature atmosphere of 250 ° C. and a small temperature change rate of capacitance at −55 ° C. to 250 ° C., and an electronic component using the same. That is.

In order to achieve the above object, the dielectric composition of the present invention is a dielectric composition having a main component and a first subcomponent.
The main component is a tungsten bronze type composite oxide represented by the _{chemical formula Ba α} R (Ti _1.00-x Zr _x ) _2.00 (Nb _{1.00-y T y} ) _3,000 O _{13.00 + α.} Including
R is a rare earth element
The α, x and y are
2.05 ≤ α ≤ 2.25
0.40 ≤ x ≤ 1.00
0.05 ≤ y ≤ 0.60
And
The first subcomponent contains an oxide of V and an oxide of W as essential components.
The first subcomponent further comprises an oxide of Si and / or an oxide of Ge.
The content of the oxide of V with respect to 100 mol of the main component is C _V (mol) in terms of V, the content of the oxide of W is C _W (mol) in terms of W, and the content of the oxide of Si is _{C Si} (mol) in terms of _{Si, and C Ge} (mol) in terms of Ge oxide content _{0.30 ≤ C V} ≤ 10.0
0.10 ≤ C _W ≤ 2.5
5.00 ≤ C _Si + C _Ge ≤ 20.00
3.0 ≤ C _V / C _W ≤ 20.0
It is characterized by being.

Due to the above characteristics of the dielectric composition, a relatively high relative permittivity suitable for use in a temperature range of about 250 ° C. and a good temperature change of capacitance in -55 ° C. to 250 ° C. It becomes possible to provide a dielectric composition having a ratio.

Further, a second subcomponent may be contained, and the second subcomponent contains one or more oxides selected from Ni oxide, Fe oxide, Eu oxide and Mo oxide.
The content of the Ni oxide with respect to 100 mol of the main component is C _Ni (mol) in terms of Ni, the content of the oxide of Fe is C _Fe (mol) in terms of Fe, and the content of the oxide of Eu is _{C Eu} (mol) in terms of _{Eu, and C Mo} (mol) in terms of Mo for the oxide content of the Mo.
0.25 ≤ C _Ni + C _Fe + C _Eu + C _Mo ≤ 2.50
It may be.

R may be La.

The electronic component according to the present invention is an electronic component having a dielectric and an electrode.
The dielectric comprises the above dielectric composition.

The laminated electronic component according to the present invention is a laminated electronic component having a laminated portion formed by alternately laminating a dielectric layer and an internal electrode layer.
The dielectric layer comprises the above dielectric composition.

An electronic component having a dielectric made of the above-mentioned dielectric composition and a laminated electronic component having a laminated portion made by laminating a dielectric layer made of the above-mentioned dielectric composition can be used from a low temperature region of about −55 ° C. It can be used for in-vehicle electronic components that are required to be used in a high temperature region of about 150 ° C. Further, it can be used as a snubber capacitor for a power device using a SiC or GaN-based semiconductor, which is required to be used in a high temperature region of about 250 ° C. Further, it can be used as a capacitor or the like used for noise removal in an automobile engine room, which is required to be used in a high temperature region of about 250 ° C.

According to the present invention, a high temperature of 250 ° C. corresponding to applications such as a multilayer ceramic capacitor used for an in-vehicle electronic component and a multilayer ceramic capacitor mounted on an electronic circuit using a power semiconductor whose substrate is SiC, GaN or the like. It is possible to provide a dielectric composition having a relatively high relative permittivity and a good temperature change rate of capacitance in an atmosphere, and an electronic component and a laminated electronic component using the same.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to FIG.

The laminated ceramic capacitor 1, which is a kind of laminated electronic component according to the present embodiment, has a capacitor element main body 10 having a structure in which a dielectric layer 2 and an internal electrode layer 3 are alternately laminated. At both ends of the capacitor element main body 10, a pair of external electrodes 4 that conduct with the internal electrode layers 3 alternately arranged inside the capacitor element main body 10 are formed. The shape of the capacitor element main body 10 is arbitrary, but is usually a rectangular parallelepiped shape. In addition, the dimensions are also arbitrary, and may be set to appropriate dimensions according to the intended use. Further, a portion in which the dielectric layer 2 and the internal electrode layer 3 are alternately laminated is referred to as a laminated portion.

The internal electrode layers 3 are laminated so that their respective ends are alternately exposed on the surfaces of the two opposite end faces of the capacitor element main body 10. The pair of external electrodes 4 are formed on both end faces of the capacitor element main body 10 and are connected to the exposed ends of the alternately arranged internal electrode layers 3 to form a capacitor circuit.

The thickness of the dielectric layer 2 is arbitrary, but is preferably 100 μm or less, and more preferably 30 μm or less per layer. The lower limit of the thickness is arbitrary, but is, for example, about 0.5 μm.

The number of layers of the dielectric layer 2 is arbitrary, but is preferably 20 or more, and more preferably 50 or more.

The type of conductive material contained in the internal electrode layer 3 is arbitrary. Ni, Ni-based alloys, Cu or Cu-based alloys are preferable. More preferably, it is a Ni or Ni-based alloy. More preferably, the main component of the internal electrode layer 3 is a Ni or Ni-based alloy, and one or more selected from Al, Si, Li, Cr and Fe are contained as subcomponents. The main component of the internal electrode layer 3 refers to a component contained in an amount of 85 wt% or more with respect to the entire internal electrode layer 3.

By using Ni or a Ni-based alloy as the main component of the internal electrode layer 3 and containing one or more selected from Al, Si, Li, Cr and Fe as subcomponents, Ni contained in the internal electrode layer 3 is oxidized. It becomes difficult to be done. Further, even if the monolithic ceramic capacitor 1 is continuously used at a high temperature of about 250 ° C., deterioration of continuity and conductivity due to oxidation of the internal electrode layer 3 is less likely to occur.

The reason why Ni contained in the internal electrode layer 3 is less likely to be oxidized by containing one or more selected from Al, Si, Li, Cr and Fe as a sub-component is as follows. When one or more selected from Al, Si, Li, Cr and Fe is contained as a sub-component, the above-mentioned sub-component reacts with oxygen before Ni reacts with oxygen in the atmosphere to become NiO. , An oxide film of the above subcomponent is formed on the surface of Ni contained in the internal electrode 3. As a result, oxygen in the outside air cannot react with Ni unless it passes through the oxide film, so that Ni is less likely to be oxidized.

The internal electrode layer 3 may contain various trace components such as P in an amount of about 0.1% by mass or less. Further, the internal electrode layer 3 may be formed by using a commercially available electrode paste. The thickness of the internal electrode layer 3 may be appropriately determined according to the application and the like.

The conductive material contained in the external electrode 4 is arbitrary. In this embodiment, for example, inexpensive Ni or Cu, highly heat-resistant Au, Ag or Pd, or an alloy of Ni, Cu, Au, Ag and / or Pd can be used. The thickness of the external electrode 4 may be appropriately determined depending on the application and the like, but is usually preferably about 10 to 50 μm.

Next, the dielectric composition constituting the dielectric layer 2 according to the present embodiment will be described in detail.

The dielectric composition according to this embodiment is
A dielectric composition having a main component and a first subcomponent.
The main component is a tungsten bronze type composite oxide represented by the _{chemical formula Ba α} R (Ti _1.00-x Zr _x ) _2.00 (Nb _{1.00-y T y} ) _3,000 O _{13.00 + α.} Including
R is a rare earth element
The α, x and y are
2.05 ≤ α ≤ 2.25
0.40 ≤ x ≤ 1.00
0.05 ≤ y ≤ 0.60
And
The first subcomponent contains an oxide of V and an oxide of W as essential components.
The first subcomponent further comprises an oxide of Si and / or an oxide of Ge.
The content of the oxide of V with respect to 100 mol of the main component is C _V (mol) in terms of V, the content of the oxide of W is C _W (mol) in terms of W, and the content of the oxide of Si is _{C Si} (mol) in terms of _{Si, and C Ge} (mol) in terms of Ge oxide content _{0.30 ≤ C V} ≤ 10.0
0.10 ≤ C _W ≤ 2.5
5.00 ≤ C _Si + C _Ge ≤ 20.00
3.0 ≤ C _V / C _W ≤ 20.0
It is characterized by being.

The type of R is arbitrary, but it is preferable to use La as R. By using La as R, (uniform sintered particles) can be easily obtained. Further, the content of La with respect to the whole R is preferably 50 mol% or more, and most preferably R is substantially composed of only La. The fact that R is substantially composed of only La means that the content of La with respect to the entire R is 95 mol% or more.

Since the dielectric composition has the above characteristics, the multilayer ceramic capacitor 1 has a high high temperature load life even when the interlayer thickness of the dielectric layer 2 is reduced to 0.5 μm to 30 μm. Further, it is possible to provide a dielectric composition and a monolithic ceramic capacitor 1 having a good relative permittivity at a high temperature of about 250 ° C. and a good temperature change rate of capacitance at −55 ° C. to 250 ° C. The factors for obtaining such an effect are shown below.

In the present embodiment, by setting 2.05 ≦ α ≦ 2.25, a high relative permittivity and a low relative permittivity temperature change rate can be obtained in the temperature range of −55 ° C. to 150 ° C. As a result, the monolithic ceramic capacitor 1 having a good capacitance temperature change rate can be obtained in the temperature range of −55 ° C. to 150 ° C.

In the present embodiment, by setting 0.40 ≦ x ≦ 1.00 and 0.05 ≦ y ≦ 0.60, the temperature has a high relative permittivity and a low relative permittivity in the temperature range of 0 ° C. to 200 ° C. The rate of change is obtained. As a result, a monolithic ceramic capacitor having a good capacitance temperature change rate can be obtained in the temperature range of 0 ° C. to 200 ° C.

From the above, by satisfying all of 2.05 ≦ α ≦ 2.25, 0.40 ≦ x ≦ 1.00 and 0.05 ≦ y ≦ 0.60, comparison is made in the temperature range of −55 ° C. to 200 ° C. Even with a relatively high relative permittivity, the effect of reducing the temperature change rate of the relative permittivity can be obtained. As a result, a monolithic ceramic capacitor having a good capacitance temperature change rate can be obtained in the temperature range of −55 ° C. to 200 ° C.

The dielectric composition according to the present embodiment contains an oxide of V and an oxide of W as essential components as a first subcomponent. Further, it contains an oxide of Si and / or an oxide of Ge. Thereby, the temperature change rate of the capacitance can be improved. The content of V oxide with respect to 100 mol of the main component is C _V (mol) in V conversion, the content of W oxide is C _W (mol) in W conversion, and the content of Si oxide is C in Si conversion. _{The oxide content of Si} (mol) and Ge is defined as C _Ge (mol) in terms of Ge. By setting 0.30 ≤ C _V ≤ 10.0, 0.10 ≤ C _W ≤ 2.5, 5.00 ≤ C _Si + C _Ge ≤ 20.00, the relative permittivity can be increased from -55 ° C to 250 ° C. The rate of temperature change can be reduced. As a result, the monolithic ceramic capacitor 1 having a good capacitance temperature change rate can be obtained in the temperature range of −55 ° C. to 250 ° C.

Further, the dielectric composition according to the present embodiment has a content ratio (C _V / C _W ) of V oxide and W oxide contained as a first subcomponent of 3.0 ≦ C _V / C. _By setting W ≦ 20.0, it is possible to achieve both a relatively high relative permittivity while having a good temperature change rate of the relative permittivity. As a result, it was possible to obtain a monolithic ceramic capacitor having a good capacitance temperature change rate while maintaining a relatively high relative permittivity in the temperature range of −55 ° C. to 250 ° C.

The dielectric composition according to the present embodiment is composed of a main phase particle mainly composed of a main component and a grain boundary existing between the main phase particles. The ratio of the principal component to the main phase particles is, for example, 90 wt% or more on average. The particle size of the main phase particles is also arbitrary. For example, the average may be 0.5 μm or more and 2.0 μm or less.

In the present embodiment, the first subcomponent V oxide, W oxide, Si oxide and Ge oxide are the main components Ba _α R (Ti _1.00-x Zr _x ) _{2 .00 (Nb 1.00-y Ta y} ) 3.00 O 13.00 + α may also be dissolved in may be present in the grain boundary without solid solution in the main phase grains. In either case, a good rate of change in capacitance can be obtained.

The dielectric composition according to the present embodiment contains, as a second subcomponent, one or more oxides selected from Ni oxide, Fe oxide, Eu oxide and Mo oxide. You may. For 100 mol of the main component, the Ni oxide content is C _Ni in terms of Ni, the Fe oxide content is C _Fe in Fe conversion, and the Eu oxide content is C _{Eu in Eu conversion.} , Mo oxide content is preferably C Mo in terms of _Mo , and is preferably 0.25 ≤ 0.25 ≤ C _Ni + C _Fe + C _Eu + C _Mo ≤ 2.50. By containing a total of 0.25 mol to 2.50 mol of the second sub-component, the effect of improving the temperature change rate of the relative permittivity can be obtained. As a result, it becomes possible to provide a dielectric composition having a better rate of change in capacitance at −55 ° C. to 250 ° C.

As described above, since the dielectric composition according to the present embodiment exhibits good characteristics in a high temperature region, it can be suitably used in the operating temperature range (-55 ° C. to 250 ° C.) of a SiC or GaN-based power device. can. Further, it can be suitably used as an electronic component for noise removal in a harsh environment such as an engine room of an automobile.

Further, the dielectric composition according to the present embodiment contains minute impurities and subcomponents other than the first subcomponent and the second subcomponent unless the rate of change in temperature of the capacitance is significantly deteriorated. It may be included. For example, Cr, Zn, Cu, Ga and the like may be contained in the dielectric composition. Therefore, the content of the principal component in the entire dielectric composition is arbitrary. For example, it may be 65 mol% or more and 94.6 mol% or less with respect to the whole dielectric composition.

Next, an example of the manufacturing method of the multilayer ceramic capacitor 1 of the present embodiment will be described. Further, in the following manufacturing method, a case where R is La will be described.

In the multilayer ceramic capacitor 1 of the present embodiment, like the conventional multilayer ceramic capacitor, a green chip is produced by a normal printing method or a sheet method using a paste, and after firing, an external electrode is applied and fired. Manufactured by Hereinafter, the manufacturing method will be specifically described.

First, the pre-baked powder of the main component is prepared. Main component Ba _α La (Ti _1.00-x Zr _x ) _2.00 (Nb _{1.00-y T y} ) _3,000 O _{13.00 + α as} a starting material for Ba, La, Ti, Zr, Ta And Nb-based oxides and mixture powders are prepared. The average particle size of each powder is preferably 1.0 μm or less. Further, various compounds that become oxides by firing, for example, carbonates, oxalates, nitrates, hydroxides, organic metal compounds and the like can be appropriately selected and mixed for use. After each starting material is weighed to a predetermined ratio, wet mixing is performed for a predetermined time using a ball mill or the like. After drying the mixed powder was heat-treated for 1000 ° C. or less in the atmosphere, which is the main component _{Ba α La (Ti 1.00-x} Zr x) 2.00 (Nb 1.00-y Ta y) 3.00 Obtain a _heat-treated powder of O 13.00 + α.

Next, the temporary baking powder of the auxiliary component is prepared. As the first subcomponent, V oxide powder, W oxide powder, Si oxide powder and Ge oxide powder having an average particle size of 2.0 μm or less are prepared as starting materials. Further, if necessary, an oxide powder of Ni, Fe, Eu, and Mo having an average particle size of 2.0 μm or less, which is a starting material for the second subcomponent, is prepared. After weighing these at a predetermined ratio, wet mixing is performed for a predetermined time using a ball mill or the like. Further, various compounds that become oxides by firing, for example, carbonates, oxalates, nitrates, hydroxides, organic metal compounds and the like can be appropriately selected and mixed for use. Then, after the mixed powder is dried, it is heat-treated in the air at 700 ° C. to 800 ° C. for 1 hour to 5 hours to obtain a calcined powder of an auxiliary component. A mixed powder that has been dried without heat treatment may be used.

Then, the obtained calcined powder of the main component and the calcined powder of the sub-component or the mixed powder of the sub-component are mixed and crushed to obtain a raw material for the dielectric composition. The average particle size of the dielectric composition raw material is arbitrary. For example, it is 0.5 μm to 2.0 μm.

The obtained dielectric composition raw material is made into a paint to prepare a paste for a dielectric layer. The paste for the dielectric layer may be an organic paint obtained by kneading a mixed dielectric powder and an organic vehicle, or may be a water-based paint.

An organic vehicle is a binder dissolved in an organic solvent. The type of binder used for the organic vehicle is arbitrary, and may be appropriately selected from various binders usually used in the present technical field such as ethyl cellulose and polyvinyl butyral. The type of organic solvent is also arbitrary. Depending on the method for producing the multilayer ceramic capacitor (for example, the printing method, the sheet method, etc.), various organic solvents such as terpineol, butyl carbitol, and acetone may be appropriately selected.

When the paste for the dielectric layer is used as a water-based paint, the water-based vehicle in which a water-soluble binder, a dispersant, or the like is dissolved in water may be kneaded with the dielectric material. The type of water-soluble binder used for the water-based vehicle is arbitrary. For example, polyvinyl alcohol, cellulose, water-soluble acrylic resin and the like can be used.

The paste for the internal electrode layer is obtained by kneading the above-mentioned conductive material made of various conductive metals and alloys, or the above-mentioned various oxides, organic metal compounds, resinates and the like which become the above-mentioned conductive material after firing, and the above-mentioned organic vehicle. Prepare.

The paste for the external electrode can be prepared in the same manner as the paste for the internal electrode layer described above.

The content of the organic vehicle in each of the above-mentioned pastes is not particularly limited, and may be a normal content, for example, about 1% by mass to 5% by mass for the binder and about 10% by mass to 50% by mass for the solvent. Further, each paste may contain an additive selected from various dispersants, plasticizers, dielectric materials, insulator materials and the like, if necessary. The total content of these is preferably 10% by mass or less.

The type of dispersant is arbitrary. For example, a surfactant-type dispersant and a polymer-type dispersant can be used. The type of plasticizer is arbitrary. For example, dioctyl phthalate and dibutyl phthalate can be used. The type of dielectric material is arbitrary. For example, BaTiO ₃ system and CaZrO ₃ system can be used. The type of insulator material is arbitrary. For example, Al ₂ O ₃ and SiO ₂ can be used.

When the printing method is used, the paste for the dielectric layer and the paste for the internal electrode layer are printed and laminated on a substrate such as PET, cut into a predetermined shape, and then peeled from the substrate to obtain a green chip.

When the sheet method is used, a green sheet is formed using the paste for the dielectric layer, the paste for the internal electrode layer is printed on the green sheet, and then these are laminated to form a green chip.

Before firing, the green chips may be subjected to a binder removal treatment. The binder removal processing conditions are arbitrary. The heating rate is preferably 5 ° C./hour to 300 ° C./hour, the holding temperature is preferably 180 ° C. to 500 ° C., and the temperature holding time is preferably 0.5 hour to 24 hours. The atmosphere of the binder removal treatment is air or a reducing atmosphere. Further, in the above-mentioned debinder treatment, _{the method of humidifying the N 2} gas, the mixed gas, or the like is arbitrary. For example, a wetter or the like may be used. In this case, the water temperature is preferably about 5 ° C to 75 ° C.

Moreover, the holding temperature at the time of firing is arbitrary. It is preferably 1100 ° C to 1400 ° C. If the holding temperature is too low, the densification will be insufficient. If the holding temperature is too high, the electrode is likely to be interrupted due to abnormal sintering of the internal electrode layer, and the capacity change rate is likely to deteriorate due to diffusion of the internal electrode layer constituent material. Further, the main phase particles may become coarse and the high temperature load life may be shortened.

The rate of temperature rise during firing is arbitrary. Preferably, it is set to 200 ° C./hour to 5000 ° C./hour. The temperature holding time during firing and the cooling rate after firing are arbitrary. In order to control the particle size distribution of the main phase particles after sintering within the range of 0.5 μm to 5.0 μm and suppress the volume diffusion between the main phase particles, the temperature holding time during firing is preferably 0.5 hours. The cooling rate after firing is preferably 100 ° C./hour to 500 ° C./hour for ~ 2.0 hours.

Further, as the atmosphere for firing, it is preferable to use a mixed gas of _{humidified N 2} and H ₂ ^{and fire at an oxygen partial pressure of 10-2} to ^{10-6 Pa.} However, when the internal electrode layer contains Ni and firing is performed in a state where the oxygen partial pressure is high, Ni may be oxidized and the conductivity may be lowered. As described above, the oxidation resistance of Ni is improved by adding one or more kinds of sub-components for internal electrodes selected from Al, Si, Li, Cr, and Fe to the conductive material containing Ni as the main component. However, even when firing in an atmosphere with a high oxygen partial pressure, it becomes easy to secure the conductivity of the internal electrode layer.

After firing, the obtained capacitor element main body is annealed as necessary. The annealing treatment conditions may be known conditions. For example, it is preferable that the oxygen partial pressure during the annealing treatment is higher than the oxygen partial pressure during firing, and the holding temperature is 1000 ° C. or lower.

Further, in the above manufacturing method, the binder removal treatment, the firing and the annealing treatment are performed independently, but they may be performed continuously.

The capacitor element body obtained as described above is subjected to end face polishing by, for example, barrel polishing or sandblasting, and an external electrode paste is applied and fired to form an external electrode 4. Then, if necessary, a coating layer is formed on the surface of the external electrode 4 by plating or the like.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention, but the present invention is not limited to these examples.

(Experimental Example 1)
First, each powder _{of BaCO 3} , La (OH) ₃ , TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , and Nb ₂ O _{5 having} an average particle size of 1.0 μm or less was prepared as a starting material for the main component. Main component Ba _alpha La contained in the finally dielectric composition obtained _{(Ti 1.00-x Zr x)} 2.00 (Nb 1.00-y Ta y) 3.00 O 13.00 + α is These raw materials were weighed so as to satisfy α, x and y shown in Tables 1 and 2. Then, ethanol was used as a dispersion medium and wet-mixed by a ball mill for 24 hours. Then, the obtained mixture was dried to obtain a mixed raw material powder. Then, heat treatment was carried out in the air under the conditions of a holding temperature of 900 ° C. and a holding time of 2 hours to obtain a calcined powder as a main component.

Was then prepared powders of _{V 2 O 5, WO 3,} SiO 2 and GeO ₂ as starting materials in the first subcomponent. _{NiO, FeO, Eu 2} O ₃ and MoO ₃ powders were prepared as starting materials for the second subcomponent. The average particle size of the starting material of the first auxiliary component and the starting material of the second auxiliary component was set to 0.2 μm or more and 2.0 μm or less. These starting materials were weighed so as to have the compounding ratios shown in Table 1. Then, using ethanol as a dispersion medium, the starting materials of each subcomponent were wet-mixed for 24 hours by a ball mill. Then, the obtained mixture was dried to obtain a mixed powder. Then, heat treatment was carried out in the air under the conditions of a holding temperature of 800 ° C. and a holding time of 2 hours to obtain a calcined powder of an auxiliary component.

The main component calcined powder and the sub-component calcined powder obtained by the above method were mixed and crushed to obtain a raw material for a dielectric composition. Next, a toluene + ethanol solution (toluene: ethanol = 50: 50 (weight ratio)), a plasticizer (dioctyl phthalate (DOP) (manufactured by J-PLUS)) and a dispersant (manufactured by J-PLUS Co., Ltd.) and a dispersant (toluene: ethanol = 50: 50 (weight ratio)) and a dispersant (manufactured by J-PLUS Co., Ltd.) and a dispersant (toluene: ethanol = 50: 50 (weight ratio)) and a plasticizer (dioctyl phthalate (DOP) (manufactured by J-PLUS Co., Ltd.)) 700 g of a solvent prepared by mixing Marialim AKM-0531 (manufactured by Nichiyu) at a ratio of 90: 6: 4 (weight ratio) was added. Next, the paste was dispersed for 2 hours using a basket mill to prepare a paste for a dielectric layer. In all the examples and comparative examples, the viscosity of the dielectric layer paste was adjusted to be about 200 cps. Specifically, the viscosity was adjusted by adding a small amount of a toluene + ethanol solution.

As raw materials for the internal electrode layer, Ni oxide having an average particle size of 0.2 μm, Al oxide having an average particle size of 0.1 μm or less, and Si oxide having an average particle size of 0.1 μm or less are prepared. Weighed and mixed so that the total of Al and Si was 5% by mass with respect to Ni. Then, the raw material powder having an average particle size of 0.20 μm was prepared by heat-treating in a mixed gas of _{N 2} and H ₂ humidified at 1200 ° C. or higher and crushing the mixture using a ball mill or the like.

100 parts by mass of the raw material powder, 30 parts by mass of an organic vehicle (8 parts by mass of ethyl cellulose resin dissolved in 92 parts by mass of butyl carbitol), and 8 parts by mass of butyl carbitol are kneaded and pasted with three rolls to form an inside. A paste for the electrode layer was obtained.

Then, the prepared paste for the dielectric layer was applied onto the PET film to form a green sheet. At this time, the thickness of the green sheet after drying was adjusted to 10 μm. Next, a predetermined pattern of the internal electrode layer was printed on the green sheet using the internal electrode layer paste. Then, by peeling the green sheet from the PET film, a green sheet in which the internal electrode layer was printed in a predetermined pattern was produced. Next, a plurality of green sheets on which the internal electrode layer was printed in a predetermined pattern were laminated and pressure-bonded to obtain a green laminate. Further, a green chip was obtained by cutting the green laminate into a predetermined shape.

Next, the obtained green chips were subjected to a binder removal treatment, a firing treatment, and an annealing treatment to obtain a laminated ceramic fired body. The conditions for debinder treatment, firing and annealing are as shown below. In addition, a wetter was used for humidifying the atmospheric gas in the binder removal treatment, firing and annealing treatment.

(Binder removal processing)
Temperature rise rate: 100 ° C / hour Holding temperature: 400 ° C
Temperature holding time: 8.0 hours Atmospheric gas: Mixed gas of _{humidified N 2} and H ₂

(Baking)
Temperature rise rate: 500 ° C / hour Holding temperature: 1200 ° C to 1350 ° C
Temperature holding time: 2.0 hours Cooling rate: 100 ° C / hour Atmospheric gas: _{Mixed gas of humidified N 2} and H ₂ Oxygen partial pressure: ^10-5 to ^10-9 Pa

(Annealing process)
Holding temperature: 800 ° C to 1000 ° C
Temperature holding time: 2.0 hours Raising and lowering rate: 200 ° C / hour Atmospheric gas: Humidified N ₂ gas

The composition of the dielectric layer (dielectric composition) of each of the obtained laminated ceramic sintered bodies is analyzed by using ICP emission spectroscopic analysis, and the composition is substantially the same as the composition shown in Table 1. It was confirmed. In addition, X-ray diffraction measurement was performed, and it was confirmed from the X-ray diffraction pattern that it had a tungsten bronze type crystal structure.

After polishing the end face of the obtained multilayer ceramic sintered body by sandblasting, In—Ga eutectic alloy was applied as an external electrode to obtain each laminated ceramic capacitor sample having the same shape as the laminated ceramic capacitor shown in FIG. .. The sizes of the obtained multilayer ceramic capacitor samples are 3.2 mm × 1.6 mm × 1.2 mm, the thickness of the dielectric layer is 7 μm, the thickness of the internal electrode layer is 2 μm, and the dielectric material sandwiched between the internal electrode layers. The number of layers was 50.

The obtained multilayer ceramic capacitor sample was measured and evaluated by the methods shown below for the relative permittivity, the rate of change in capacitance, the resistivity, the withstand voltage of DC, and the high temperature load life, and are shown in Tables 3 and 4.

[Relative permittivity at 250 ° C]
A signal having a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms was input to the multilayer ceramic capacitor sample at 250 ° C. with a digital LCR meter (4284A manufactured by YHP), and the capacitance was measured. Then, the relative permittivity (without unit) was calculated based on the thickness of the dielectric layer, the effective electrode area, and the capacitance obtained as a result of the measurement. The higher the relative permittivity, the better, and in this example, 500 or more was judged to be good.

[Cacitance temperature change rate]
Multilayer Ceramic Capacitor A capacitor sample was placed in a constant temperature bath manufactured by Despatch, and the capacitance was measured at a measurement voltage of 1 Vrms in a temperature range of −55 to 250 ° C. Then, +25 capacitance at ° C. capacitance at a temperature T (° C.) for _{(C 25) (C T)} rate of change _{(ΔC T / C 25 (%} )) a, ΔC _T / _C 25 = { _{(C T -C 25) / C} 25} was calculated from the formula of × 100. The rate of change in capacitance was measured between the case of T = −55 ° C. and the case of T = 250 ° C. In this embodiment, when the temperature change rate of the capacitance is within the range of ± 15% when T = −55 ° C. and when T = 250 ° C., it is considered to be good, and it is within the range of ± 10%. Was made even better.

[Specific resistance at 250 ° C]
The insulation resistance of the multilayer ceramic capacitor sample was measured at 250 ° C. with a digital resistance meter (R8340 manufactured by ADVANTEST) under the conditions of a measurement voltage of 350 V (50 V / μm) and a measurement time of 60 seconds. The specific resistance was calculated from the measured value of insulation resistance, the electrode area of the capacitor sample, and the thickness of the dielectric layer. It is preferable that the specific resistance is high, and in this example, 1.00 × 10 ¹⁰ Ωcm or more was judged to be good. More preferably, it is 1.00 × 10 ¹¹ Ωcm or more.

According to the results shown in Tables 3 and 4, the multilayer ceramic capacitor sample within the range of the present invention has a relative permittivity of 500 or more and a specific resistance of 1.00 × 10 ¹⁰ Ωcm or more at 250 ° C. It was confirmed that the temperature change rate of the capacitance was within ± 15%.

On the other hand, when it is outside the scope of the present invention, it is confirmed that the action of suppressing the temperature change of the capacitance is not sufficiently obtained and the absolute value of the temperature change rate of the capacitance becomes too large. did it.

Further, each sample containing 0.25 mol to 2.50 mol of the second sub-component with respect to 100 mol of the main component further increases the specific resistance at 250 ° C. and further reduces the absolute value of the temperature change rate of the capacitance. It was confirmed that there is an effect of

(Experimental Example 2)
Sample No. For 63, each multilayer ceramic capacitor sample shown in Table 5 was prepared by changing the type of rare earth element and the like, and various characteristics were evaluated. The results are shown in Tables 5 and 6.

From Tables 5 and 6, the same tendency was shown even when the types of rare earth elements were changed.

It should be considered that the embodiments and examples disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is not shown in the above embodiments and examples, but is indicated by the claims and is intended to include all modifications and modifications within the meaning and scope equivalent to the claims.

Since the dielectric composition of the present invention has a high high-temperature load life in a high-temperature region of 250 ° C., it can be applied to an environment close to an engine room for in-vehicle use, and further, a power device using a SiC or GaN-based semiconductor. It can also be applied to applications as electronic components mounted in the vicinity.

1 Multilayer ceramic capacitor 2 Dielectric layer 3 Internal electrode layer 4 External electrode 10 Capacitor element body

Claims (5)

A dielectric composition having a main component and a first subcomponent.
The main component is a tungsten bronze type composite oxide represented by the _{chemical formula Ba α} R (Ti _1.00-x Zr _x ) _2.00 (Nb _{1.00-y T y} ) _3,000 O _{13.00 + α.} Including
R is a rare earth element
The α, x and y are
2.05 ≤ α ≤ 2.25
0.40 ≤ x ≤ 1.00
0.05 ≤ y ≤ 0.60
And
The first subcomponent contains an oxide of V and an oxide of W as essential components.
The first subcomponent further comprises an oxide of Si and / or an oxide of Ge.
The content of the oxide of V with respect to 100 mol of the main component is C _V (mol) in terms of V, the content of the oxide of W is C _W (mol) in terms of W, and the content of the oxide of Si is _{C Si} (mol) in terms of _{Si, and C Ge} (mol) in terms of Ge oxide content _{0.30 ≤ C V} ≤ 10.0
0.10 ≤ C _W ≤ 2.5
5.00 ≤ C _Si + C _Ge ≤ 20.00
3.0 ≤ C _V / C _W ≤ 20.0
A dielectric composition characterized by being. Further, it contains a second subcomponent, and the second subcomponent contains one or more oxides selected from Ni oxide, Fe oxide, Eu oxide and Mo oxide.
The content of the Ni oxide with respect to 100 mol of the main component is C _Ni (mol) in terms of Ni, the content of the oxide of Fe is C _Fe (mol) in terms of Fe, and the content of the oxide of Eu is _{C Eu} (mol) in terms of _{Eu, and C Mo} (mol) in terms of Mo for the oxide content of the Mo.
0.25 ≤ C _Ni + C _Fe + C _Eu + C _Mo ≤ 2.50
The dielectric composition according to claim 1. The dielectric composition according to claim 1 or 2, wherein R is La. An electronic component with a dielectric and electrodes
An electronic component in which the dielectric is the dielectric composition according to any one of claims 1 to 3. A laminated electronic component having a laminated portion formed by alternately laminating a dielectric layer and an internal electrode layer.
A laminated electronic component in which the dielectric layer comprises the dielectric composition according to any one of claims 1 to 3.

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