JP6972993B2 - Dielectric composition and 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 substrate is SiC, GaN, etc., a high temperature region of about 250 ° C. Guarantee up to is required, and high reliability is required so that the function as a capacitor does not deteriorate at least up to about 250 ° C. That is, it is important to have a high high temperature load life.

Patent Document 1 discloses a dielectric ceramic composition that exhibits a sufficient dielectric constant and can obtain stable capacitance temperature characteristics 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 an auxiliary component with respect to 100 mol parts of the main component. It is characterized by doing.

Patent Document 2 describes a dielectric ceramic composition containing a tungsten bronze-type composite oxide represented by the chemical formula (K _1-x Na _x ) Sr ₂ Nb ₅ O _{15 (0 ≦ x <0.2) as a main component.} In the above, by containing 0.05 to 20 mol parts of rare earth elements and 0.05 mol to 40 mol parts of Mn, V, Li and the like as subcomponents, a dielectric ceramic composition having a high resistivity at room temperature can be obtained. It has been disclosed.

Patent Document 3 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, the dielectric ceramic composition described in Patent Document 1 is insufficient in terms of high temperature load life. Further, the dielectric ceramic composition described in Patent Document 2 is insufficient in terms of high temperature load life at about 250 ° C. Further, in Patent Document 3, since the main component is barium titanate, the relative permittivity sharply decreases in the temperature range exceeding 150 ° C., and the capacitance decreases.

International Publication No. 2008/155945 International Publication No. 2008/102608 Japanese Unexamined Patent Publication No. 2008-162830

An object of the present invention is to provide a dielectric composition having a high withstand voltage and a high high temperature load life in a high temperature atmosphere of 250 ° C., and an electronic component using the dielectric composition.

In order to achieve the above object, the dielectric composition according to the present invention is
A dielectric composition having a main component and a first subcomponent.
The main component contains an oxide represented by the _{chemical formula Ba 2.00} RZr _α Nb _3.00 O _{13.00 + α.}
R is a rare earth element
The α is 2.05 or more and 2.50 or less.
The first sub-component contains an oxide of V and an oxide of Ca 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 Ca is C _Ca (mol) in terms of Ca, 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 _{0.50 ≤ C V} ≤ 5.00
3.50 ≤ C _Ca ≤ 9.00
7.50 ≤ C _Si + C _Ge ≤ 20.00
It is characterized by being.

Since the dielectric composition has the above-mentioned characteristics, a dielectric composition having a high withstand voltage and a high high-temperature load life suitable for use in a temperature range of about 250 ° C., and electronic components using the dielectric composition can be obtained. It will be possible to provide.

The α is 2.15 or more and 2.40, and the α is 2.15 or more and 2.40.
1.00 ≤ C _V ≤ 2.50
4.50 ≤ C _Ca ≤ 7.00
May be.

Further, a second subcomponent may be contained, wherein the second subcomponent contains one or more oxides selected from W oxide, Mo oxide and Eu oxide.
The content of the oxide of W in terms of 100 mol of the main component is C _W (mol) in terms of W, the content of oxide of Mo is C _Mo (mol) in terms of Mo, and the content of oxide of Eu is. As C _Eu (mol) in terms of Eu,
0.25 ≤ C _W + C _Mo + C _Eu ≤ 5.00
May be.

R may be La.

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

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.

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 corridor using a power semiconductor whose substrate is SiC, GaN, or the like. It is possible to provide a dielectric composition having a high withstand voltage and a high high temperature load life under 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 conducting 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. Further, the dimensions are also arbitrary, and may be 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 not particularly limited, but is preferably 100 μm or less per layer, and more preferably 30 μm or less. The lower limit of the thickness is not particularly limited, but is, for example, about 0.5 μm.

The number of layers of the dielectric layer 2 is not particularly limited, but is preferably 20 or more, and more preferably 50 or more.

The type of the 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 Ni or a 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 an auxiliary 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 and oxygen react with each other before Ni reacts with oxygen in the atmosphere to form 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 intended use 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 intended use 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 contains an oxide represented by the _{chemical formula Ba 2.00} RZr _α Nb _3.00 O _{13.00 + α.}
R is a rare earth element
The α is 2.05 or more and 2.50 or less.
The first subcomponent contains an oxide of V and an oxide of Ca 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 Ca is C _Ca (mol) in terms of Ca, 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 _{0.50 ≤ C V} ≤ 5.00
3.50 ≤ C _Ca ≤ 9.00
7.50 ≤ C _Si + C _Ge ≤ 20.00
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 body particles) can be easily obtained. Further, the content of La with respect to the whole R is preferably 50 mol% or more, and it is most preferable that 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, by containing Ba and R in the main component, it is possible to obtain a dielectric composition having excellent high temperature load life and withstand voltage while maintaining a high relative permittivity. Further, by including Nb in the main component, a tungsten bronze type crystal structure is easily formed, and a dielectric composition having an excellent withstand voltage can be obtained. The factors for obtaining such an effect are shown below.

The dielectric composition according to the present embodiment is set to 2.05 ≦ α ≦ 2.50. Within the above range, the bandgap becomes wider, and a dielectric composition having an excellent withstand voltage of 250 ° C. can be obtained.

In the dielectric composition according to the present embodiment, the main component thereof preferably has a tungsten bronze type crystal structure. Whether or not the main component has a tungsten bronze type crystal structure can be confirmed by the X-ray diffraction (XRD) pattern of the dielectric composition.

The main component of the present embodiment (chemical formula Ba ₂ LaZr _α Nb ₃ O _{13 + α} ) tends to have a tungsten bronze type crystal structure.

Since the main component has a tungsten bronze type crystal structure, a high withstand voltage can be easily obtained. The inventors consider this factor as follows. When the main component of the present embodiment has a tungsten bronze-type crystal structure, the band gap becomes wide, so that it becomes difficult for electrons in the valence band to be excited to the conduction band, and electrons that are a large number of carriers involved in conduction become difficult to excite. It becomes possible to suppress the carrier concentration. Further, in the electron avalanche, which is a typical breakdown mode of withstand voltage, it is considered that the carrier concentration of conduction electrons, which are a large number of carriers, has an influence. When the main component has a tungsten bronze-type crystal structure, it is possible to keep the carrier concentration of the electrons, which are the majority carriers, low, and it is considered that the destruction by electron avalanche is less likely to occur. Further, when the bandgap is widened, it is possible to maintain a bandgap having a certain width even when a high electric field strength is applied, so that it is likely that a high withstand voltage can be easily obtained even at a high electric field.

The dielectric composition according to the present embodiment contains an oxide of V and an oxide of Ca as essential components as a first sub-component. Further, it contains an oxide of Si and / or an oxide of Ge. C _C V (mol) of the content of the oxide of V relative to the main component 100mol in V terms, _C a (mol) of the content of the oxide of Ca in Ca terms, the content of the oxide of Si in terms of Si _{The oxide content of Si} (mol) and Ge is defined as C _Ge (mol) in terms of Ge. By setting 0.50 ≤ C _V ≤ 5.00, 3.50 ≤ C _Ca ≤ 9.00, 7.50 ≤ C _Si + C _Ge ≤ 20.00, oxygen defects that are considered to be the cause of deterioration of the high temperature load life The movement of silicon is suppressed, and a sufficient high temperature load life can be obtained.

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 oxide of V, the oxide of Si, and the oxide of Ge among the first subcomponents may be solid-dissolved in the main phase particles, and are present at the grain boundaries without being solid-solved. May be. In either case, a good high temperature load life can be obtained. Further, among the first oxides, the Ca oxide is often not solid-solved in the main phase particles and tends to be present at the grain boundaries (two-particle boundary and triple point of grain boundary). Since the oxide of Ca is present at the grain boundaries, a monolithic ceramic capacitor 1 having excellent resistivity and withstand voltage at high temperature can be obtained.

It is preferable that the oxide of Si and the oxide of Ge contain substantially only one of them. For example, _{it is preferable that C Si} / (C _Si + C _Ge ) or C _Ge / (C _Si + C _Ge ) is 0.70 or more and 1.00 or less.

The dielectric composition according to this embodiment preferably has α of 2.15 or more and 2.40, and _{preferably 1.00 ≤ C V} ≤ 2.50 and 4.50 ≤ C _Ca ≤ 7.00. By keeping α, C _V and C _Ca within the above ranges, the withstand voltage and resistivity are further improved.

The dielectric composition according to the present embodiment may contain at least one or more oxides selected from W oxide, Mo oxide and Eu oxide as the second subcomponent. .. The content of the oxide of W is C _W (mol) in terms of W, the content of the oxide of Mo is C _Mo (mol) in terms of Mo, and the content of the oxide of Eu is 100 mol of the main component. _{Is C Eu} (mol) in terms of Eu, and it is preferable that _{0.25 ≤ C W} + C _Mo + C _{Eu ≤ 5.00.} By containing a total of 0.25 mol to 5.00 mol of the second subcomponent, the movement of oxygen defects, which is considered to be the cause of deterioration of the high temperature load life, is further suppressed by setting the above range, and the excellent high temperature load life is achieved. Is obtained.

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.

The dielectric composition according to the present embodiment has a small amount of impurities, the first subcomponent, and the first subcomponent, unless the characteristics such as relative permittivity, resistivity, withstand voltage, and high temperature load life are significantly deteriorated. It may contain an auxiliary component other than the auxiliary component of 2. For example, Ni, Fe, Cr, Zn, Cu, Ga and the like may be contained in the dielectric composition. The content of the principal component in the entire dielectric composition is arbitrary. For example, it may be 60 mol% or more and 97.5 mol% or less with respect to the whole dielectric composition.

Further, the dielectric composition according to the present embodiment may contain Ta and / or Ti, a part of Zr in the main component may be replaced with Ti, and a part of Nb may be replaced with Ta. May be. However, when Ta is contained, the relative permittivity tends to decrease, and when Ti is contained, the insulating property tends to decrease. Therefore, it is preferable that Ta and Ti are not substantially contained.

Further, in the dielectric composition according to the present embodiment, it is preferable that the main phase particles do not substantially contain a highly volatile alkali metal. Since the main phase particles do not contain alkali metal, some elements of the main component are replaced with alkali metal and volatilized, so that lattice defects are less likely to occur and conduction electrons are less likely to be generated, so the specific resistance is also high. It also has features. Furthermore, it is considered that the electrolytic reduction reaction is unlikely to occur under high temperature and high electric field. Therefore, it is considered that a high high-temperature load life is exhibited because the increase of conduction electrons generated by the reduction reaction can be suppressed. The term "substantially free of alkali metal" means, for example, a case where the content of the alkali metal with respect to all the elements contained in the main component is 1 at% or less.

Next, an example of the manufacturing method of the monolithic 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.

As for the multilayer ceramic capacitor 1 of the present embodiment, like the conventional laminated 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. As a starting material for the main component Ba _2.00 RZr _α Nb _3.00 O _{13.00 + α} , a powder of an oxide mainly composed of Ba, La, Zr, Nb or a mixture thereof can be used. The average particle size of each powder is preferably 1.0 μm or less. Further, it is also possible to appropriately select from various compounds which become the above-mentioned oxides and composite oxides by firing, for example, carbonates, oxalates, nitrates, hydroxides, organic metal compounds and the like, and mix and use them. After weighing each component so as to have a predetermined composition ratio, wet mixing is performed for a predetermined time using a ball mill or the like. After the obtained mixed powder is dried, it is heat-treated at 1000 ° C. or lower in the air to obtain a calcined powder of _{Ba 2.00 RZr α} Nb _3.00 O _{13.00 + α, which is the main component.}

Prepare the as-baked powder of the auxiliary ingredient. As the first auxiliary component, a V oxide powder having an average particle size of 2.0 μm or less, a Ca oxide powder, a Si oxide powder, and a Ge oxide powder can be used as a starting material. Further, as the second auxiliary component, a raw material powder of an oxide of W, Mo, Eu having an average particle size of 2.0 μm or less or a mixture thereof can be used as a starting material. Further, it is also possible to appropriately select from various compounds which become the above-mentioned oxides and composite oxides by firing, for example, carbonates, oxalates, nitrates, hydroxides, organic metal compounds and the like, and mix and use them. After weighing each component so as to have a predetermined composition ratio, wet mixing is performed for a predetermined time using a ball mill or the like. After the obtained 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 as an auxiliary component. A dried mixed powder may be used without heat treatment.

Then, the obtained calcination powder of the main component and the calcination 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 raw material of the dielectric composition 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 manufacturing the monolithic ceramic capacitor (for example, printing method, sheet method, etc.), it may be appropriately selected from various organic solvents such as terpineol, butyl carbitol, and acetone.

When the paste for the dielectric layer is used as a water-based paint, the water-based vehicle in which a water-soluble binder or a dispersant 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 may 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 on a substrate such as PET, laminated, cut into a predetermined shape, and then peeled off 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 temperature rise 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 binder removal processing, how to wet the N ₂ gas and mixed gas, etc. are 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.

Further, 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 be deteriorated due to the 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 after sintering within the range of 0.5 μm to 5.0 μm and to suppress the volume diffusion between the main phase particles, the temperature holding time during firing is preferably 0.5 hours or more. The cooling rate after firing for 2.0 hours is preferably 100 ° C./hour to 500 ° C./hour.

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 containing one or more kinds of auxiliary components for internal electrodes selected from Al, Si, Li, Cr, and Fe in 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 continuously performed.

The capacitor element main 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 can be variously modified 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.

As starting materials for the main component, BaCO ₃ , ZrO ₂ , Nb ₂ O ₅ , and La ₂ O ₃ powders having an average particle size of 1.0 μm or less were prepared. These raw materials are weighed so that the _{main component Ba 2.00} LaZr _α Nb _3.00 O _{13.00 + α} contained in the finally obtained dielectric composition satisfies the α shown in Tables 1 to 3. bottom. 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.

It was then prepared powders of _{V 2 O 5, CaCO 3,} SiO 2, GeO 2 as starting materials in the first subcomponent. _{WO 3} , MoO ₃ and Eu ₂ O ₃ powders were prepared as starting materials for the second auxiliary component. The average particle size of the starting material of the first auxiliary component and the starting material of the second auxiliary component was (0.2) μm or more and (2.0) μm or less. These were weighed so as to have the compounding ratios shown in Tables 1 to 3. Then, using ethanol as a dispersion medium, the starting materials of each auxiliary component 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 heat treatment _{changes CaCO 3} to CaO.

The calcination powder of the main component and the calcination powder of the subcomponent 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.) were added to 1000 g of the raw material of the dielectric composition. 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 paste for the dielectric layer 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 with an average particle size of 0.2 μm, an oxide of Si with an average particle size of 0.1 μm or less (Al oxide), and an oxide of Si with an average particle size of 0.1 μm or less are prepared, and Al and Weighed and mixed so that the total amount of 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% 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 by three rolls, made into a paste, and 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 set to 10 μm. Next, a predetermined pattern of the internal electrode layer was printed on the green sheet using the paste for the internal electrode layer. 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. / Time Atmosphere gas: mixed gas of oxygen partial pressure of wet N 2 and H 2: 10 -5 ~10 -9 Pa

(Annealing process)
Holding temperature: 800 ° C to 1000 ° C
Temperature retention time: 2.0 hours Temperature rise, temperature decrease rate: 200 ° C / hour Atmospheric gas: Humidified N ₂ gas

The dielectric layer (dielectric composition) of each of the obtained laminated ceramic sintered bodies was subjected to composition analysis using ICP emission spectroscopic analysis, and the composition was 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 laminated ceramic sintered body by sandblasting, an 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 all 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 sandwiched between the internal electrode layers. The number of layers was 50.

The relative permittivity, resistivity, high temperature load life, and withstand voltage of the obtained multilayer ceramic capacitor sample were measured by the methods shown below. The results are shown in Tables 4 to 6.

[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 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, 250 or more was judged to be good.

[Specific resistivity at 250 ° C]
The insulation resistance of the monolithic 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 resistivity was calculated from the electrode area of the capacitor sample and the thickness of the dielectric layer. Higher resistivity is preferable, 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.

[High temperature load life at 280 ° C]
In the high temperature load life test, a DC voltage was applied to 200 samples of each sample number so that the temperature was 280 ° C. and the measured voltage was 350 V (50 V / μm), and the change in insulation resistance with time was measured. A sample whose insulation resistance deteriorated by an order of magnitude was determined to be a failure, and the time when the failure rate became 50% from the Weibull analysis was defined as mean time between failures (MTTF), and the mean time between failures was defined as the high temperature load life. It is preferable that the high temperature load life is long, and it was judged that 500 hours or more is good in this example. More preferably, it is 1200 hours or more.

[AC withstand voltage at 250 ° C]
An AC voltage was applied to the multilayer ceramic capacitor sample at a boost speed of 100 V / sec at 250 ° C., and the AC withstand voltage was defined as the point where the leakage current exceeded 10 mA. It is preferable that the AC withstand voltage is high, and in this example, 75 V / μm or more is good. More preferably, it is 120 V / μm or more.

Each sample whose content of α and the first subcomponent is within the range of the present invention has a relative permittivity at 250 ° C., a specific resistance at 250 ° C., a high temperature load life at 280 ° C., and an alternating current at 250 ° C. It was confirmed that the withstand voltage was good.

Among them, each sample having α of 2.15 or more and 2.40 or less _{and satisfying 1.00 ≤ C V} ≤ 2.50 and 4.50 ≤ C _Ca ≤ 7.00 has a specific resistivity at 250 ° C. It was confirmed that the AC withstand voltage at 250 ° C was excellent.

The content of α and the first subcomponent is within the range of the present invention, and each sample containing the second subcomponent in an amount of 0.25 mol to 5.00 mol with respect to 100 mol of the main component is particularly at 280 ° C. It was confirmed that the high temperature load life was excellent.

(Experimental Example 2)
Sample No. For 57, each laminated ceramic capacitor sample shown in Table 7 was prepared by changing the types of rare earth elements and the like, and various characteristics were evaluated. The results are shown in Tables 7 and 8.

From Tables 7 and 8, the same tendency was shown even if the types of rare earth elements were changed.

It should be considered that the embodiments and examples disclosed here 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 shown by the scope of claims, and is intended to include all modifications and modifications within the meaning and scope equivalent to the scope of claims.

Since the dielectric composition of the present invention has a high relative permittivity and a long resistivity, withstand voltage and high temperature load life especially in a high temperature region, it can be applied as an in-vehicle electronic component in an environment close to an engine room, and further. It can also be applied as an electronic component mounted in the vicinity of a power device using a SiC or GaN-based semiconductor.

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

Claims (6)

A dielectric composition having a main component and a first subcomponent.
The main component contains an oxide represented by the _{chemical formula Ba 2.00} RZr _α Nb _3.00 O _{13.00 + α.}
R is a rare earth element
The α is 2.05 or more and 2.50 or less.
The first sub-component contains an oxide of V and an oxide of Ca 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 Ca is C _Ca (mol) in terms of Ca, 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 _{0.50 ≤ C V} ≤ 5.00
3.50 ≤ C _Ca ≤ 9.00
7.50 ≤ C _Si + C _Ge ≤ 20.00
Der is,
The dielectric composition characterized Rukoto said main component having a crystal structure of the tungsten bronze type. The α is 2.15 or more and 2.40, and the α is 2.15 or more and 2.40.
1.00 ≤ C _V ≤ 2.50
4.50 ≤ C _Ca ≤ 7.00
The dielectric composition according to claim 1. Further, it contains a second subcomponent, wherein the second subcomponent contains one or more oxides selected from W oxide, Mo oxide and Eu oxide.
The content of the oxide of W in terms of 100 mol of the main component is C _W (mol) in terms of W, the content of oxide of Mo is C _Mo (mol) in terms of Mo, and the content of oxide of Eu is. As C _Eu (mol) in terms of Eu,
0.25 ≤ C _W + C _Mo + C _Eu ≤ 2.50
The dielectric composition according to claim 1 or 2. The dielectric composition according to any one of claims 1 to 3, 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 4. It is 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 4.

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