JP2023115816A - Dielectric composition and electronic component - Google Patents

Abstract

To provide a dielectric composition which has a high sintering density even when fired at a relatively low temperature, a high relative permittivity and good temperature characteristics of capacitance.SOLUTION: There is provided a dielectric composition which has a main component and a first subcomponent, wherein the main component is a tungsten bronze type composite oxide represented by BaαR{Ti(1.00-x)Zrx}2.00{Nb(1.00-y)Tay}3.00O13.00+α, R is a rare earth element, α is 2.05≤α≤2.25, x is 0.40≤x≤1.00, y is 0.05≤y≤0.85, the first subcomponent is Mg and Si, the content of Si in terms of SiO2 based on 100 molar parts of the main component in the dielectric composition is defined as CSi molar parts and the content of Mg in terms of MgO based on 100 molar parts of the main component in the dielectric composition is defined as CMg molar parts, CMg/CSi is 0.75≤CMg/CSi≤2.0 and CMg+CSi is 15≤CMg+CSi≤30.SELECTED DRAWING: Figure 1

Description

The present invention relates to dielectric compositions and electronic components.

In Patent Document 1, the main component is a tungsten bronze type composite oxide represented by the chemical formula BaαR(Ti _1.00-x Zr _x ) _2.00 (Nb _1.00-y Ta _y ) _3.00 O _13.00+ α, and V and W and Si and/or Ge are disclosed.

In recent years, it has been desired to obtain a dielectric composition having the above-described main component, which can achieve a higher sintered density even when fired at a low temperature.

Japanese Patent No. 6922701

The present invention has been made in view of such actual circumstances, and provides a dielectric composition that has a high sintered density even when fired at a relatively low temperature, a high relative dielectric constant, and a good temperature characteristic of capacitance. With the goal.

A dielectric composition according to the present invention comprises a main component and a first subcomponent,
The main component is a tungsten bronze type composite oxide represented by BaαR {Ti _(1.00-x) Zr _x } _2.00 {Nb _(1.00-y) Ta _y } _3.00 O _13.00+ α,
The R is a rare earth element,
The α is 2.05≦α≦2.25,
The x is 0.40 ≤ x ≤ 1.00,
The y is 0.05 ≤ y ≤ 0.85,
The first subcomponent is Mg and Si,
The content of Si in terms of SiO ₂ with respect to 100 mol parts of the main component in the dielectric composition is defined as CSi mol parts,
When the content of Mg in terms of MgO with respect to 100 mol parts of the main component in the dielectric composition is defined as CMg mol parts,
CMg/CSi is 0.75≦CMg/CSi≦2.0,
CMg+CSi is 15≦CMg+CSi≦30.

The dielectric composition according to the present invention has a high sintered density and a high relative permittivity even when fired at a relatively low temperature, and the temperature characteristics of capacitance are excellent. Although the reason for this is not necessarily certain, the following reasons are conceivable. When α, x and y are within the above ranges and the dielectric composition contains both Si and Mg in predetermined amounts, it is believed that the effect of lowering the sintering start temperature is obtained. It is believed that this makes it easier to obtain a high sintered density even when fired at a relatively low temperature, improves the dielectric constant, and improves the temperature characteristics of the capacitance.

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

The dielectric composition according to the present invention preferably contains a second subcomponent,
the second subcomponent is Al,
When the content of Al in terms of Al ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CAl mol parts,
It is preferred that CA1 is contained within the range of 2.5-10.

By including the second subcomponent in the dielectric composition within the above range, the sintering initiation temperature is further lowered. As a result, the sintered density is further improved, and the temperature characteristics of the capacitance are improved. In addition, by including the second subcomponent in the dielectric composition within the above range, the effect of improving resistance to reduction can be obtained. As a result, the specific resistance is improved.

The dielectric composition according to the present invention preferably contains a third subcomponent,
the third subcomponent is at least one selected from the group consisting of Ho, Eu, Nd, Yb and Gd;
The content of Ho in terms of Ho ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CHo mol parts,
The content of Eu in terms of Eu ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CEu mol parts,
The content of Nd in terms of Nd ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CNd mol parts,
The content of Yb in terms of Yb ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CYb mol parts,
When the content of Gd in terms of Gd ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is CGd mol parts,
At least one selected from the group consisting of CHo, CEu, CNd, CYb and CGd is preferably included within the range of 2.5-10.

By including the third subcomponent in the dielectric composition within the above range, the effect of improving resistance to reduction can be further obtained. As a result, the specific resistance is further improved.

Preferably, R is La.

Further, an electronic component according to the present invention comprises the above dielectric composition.

Further, a multilayer electronic component according to the present invention is a multilayer electronic component in which dielectric layers and internal electrode layers are alternately laminated,
The dielectric layer is the above dielectric composition.

FIG. 1 is a schematic cross-sectional view of a laminated ceramic capacitor according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a thin film capacitor according to one embodiment of the present invention. FIG. 3 is a graph relating to examples of the present invention and comparative examples.

[First embodiment]
< Multilayer ceramic capacitor >
A multilayer ceramic capacitor 1, which is a type of multilayer electronic component according to this embodiment, has a capacitor element body 10 in which dielectric layers 2 and internal electrode layers 3 are alternately laminated.

A pair of external electrodes 4 are formed at both ends of the capacitor element body 10 so as to be electrically connected to the internal electrode layers 3 alternately arranged inside the capacitor element body 10 .

Although the shape of the capacitor element main body 10 is arbitrary, it is usually rectangular parallelepiped. Moreover, the dimensions thereof are arbitrary, and appropriate dimensions may be selected according to the application. A portion in which the dielectric layers 2 and the internal electrode layers 3 are alternately laminated is called a lamination portion.

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

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

Although the number of laminated dielectric layers 2 is arbitrary, it is preferably 20 or more, and more preferably 50 or more.

The type of conductive material contained in the internal electrode layers 3 is arbitrary. Ni, Ni-based alloys, Cu, or Cu-based alloys are preferred. More preferably, it is Ni or a 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. In addition, the main component of the internal electrode layer 3 refers to a component contained in the internal electrode layer 3 in an amount of 85% by mass or more.

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 is contained as an auxiliary component, so that Ni contained in the internal electrode layer 3 is oxidized. less likely to be Even if the multilayer 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 layers 3 is less likely to occur.

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

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 according to the application and the like, but it is generally preferable to be about 10 to 50 μm.

Next, the dielectric composition forming the dielectric layer 2 according to this embodiment will be described.

The dielectric composition according to the present embodiment is a tungsten bronze type composite oxidation whose main component is BaαR {Ti _(1.00-x) Zr _x } _2.00 {Nb _(1.00-y) Ta _y } _3.00 O _13.00+ α It is a thing.

R is a rare earth element. Although the type of R is arbitrary, it is preferable to use La as R. By using La as R, (uniform sintered particles) can be easily obtained. Moreover, the content of La relative to the entirety of R is preferably 50 mol % or more, and most preferably R consists essentially of La. The fact that R consists essentially of La means that the content of La is 95 mol % or more with respect to the entirety of R.

α means the content of Ba. In this embodiment, α is 2.05≦α≦2.25, preferably 2.10≦α≦2.20.

x means the content of Zr. In this embodiment, x is 0.40≤x≤1.00, preferably 0.60≤x≤0.80.

y means the content of Ta. In this embodiment, y is 0.05≤y≤0.85.

The dielectric composition according to this embodiment includes a first subcomponent. The first subcomponents are Mg and Si.

The content of Si in terms of SiO ₂ with respect to 100 mol parts of the main component in the dielectric composition is CSi mol parts, and the content of Mg in terms of MgO with respect to 100 mol parts of the main component in the dielectric composition is CMg mol. part.

In this embodiment, CMg/CSi satisfies 0.75≦CMg/CSi≦2.0.

Moreover, CMg+CSi satisfies 15≦CMg+CSi≦30.

The dielectric composition according to the present invention preferably contains a second subcomponent. The second subcomponent is Al.

The content of Al in terms of Al ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CAl mol parts.

In this embodiment, it is preferable that CA1 is contained within the range of 2.5-10.

The dielectric composition according to the present invention preferably contains a third subcomponent. The third subcomponent is at least one selected from the group consisting of Ho, Eu, Nd, Yb and Gd. That is, the third subcomponent may be of only one type, or may be a combination of two or more types.

The content of Ho in terms of Ho ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CHo mol parts. Also, the content of Eu in terms of Eu ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CEu mol parts. Also, the content of Nd in terms of Nd ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CNd mol parts. Also, the content of Yb in terms of Yb ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CYb mol parts. Also, the content of Gd in terms of Gd ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CGd mol parts.

In this embodiment, at least one selected from the group consisting of CHo, CEu, CNd, CYb and CGd is preferably included within the range of 2.5-10.

The dielectric composition according to the present embodiment is mainly composed of main phase grains composed of the main component and grain boundaries existing between the main phase grains. The ratio of the main component in the main phase particles is, for example, 90% by mass or more on average. Moreover, the particle size of the main phase particles is also arbitrary. For example, the average thickness may be 0.5 μm or more and 2.0 μm or less.

In the present embodiment, the first to third subcomponents may be solid-dissolved in the main phase grains, or may be present at grain boundaries without being solid-dissolved in the main phase grains.

In addition, the dielectric composition according to the present embodiment does not contain minute impurities or subcomponents other than the first to third subcomponents, as long as they do not significantly deteriorate the temperature change rate of the capacitance. I don't mind. For example, Cr, Zn, Cu, Ga, etc. may be included in the dielectric composition. Therefore, the content of the main component in the dielectric composition as a whole is arbitrary. For example, the elements other than oxygen constituting the main component may be 65 mol % or more and 94.6 mol % or less of the total elements other than oxygen constituting the dielectric composition.

Next, an example of a method for manufacturing the laminated ceramic capacitor 1 of this embodiment will be described. Also, in the following manufacturing method, the case where R is La will be described.

In the multilayer ceramic capacitor 1 of the present embodiment, similarly to the conventional multilayer ceramic capacitor, a green chip is produced by a normal printing method using paste or a sheet method, and after firing this, external electrodes are applied and fired. Manufactured by The manufacturing method will be specifically described below.

First, calcined powder of the main component is prepared. Powders of oxides and mixtures mainly composed of Ba, La, Zr, Nb and Ta are prepared as starting materials for the main components. The average particle size of each powder is preferably 1.0 μm or less. It is also possible to use a mixture of various compounds, such as carbonates, oxalates, nitrates, hydroxides, organometallic compounds, etc., which are converted into the above-mentioned oxides by firing. After weighing each starting material in a predetermined ratio, wet mixing is performed for a predetermined time using a ball mill or the like. After drying the mixed powder, heat treatment is performed at 1000° C. or less in the atmosphere to obtain calcined powder of the main component.

Next, calcining powder as an accessory component is prepared. For the first subcomponent, Si oxide powder and Mg oxide powder having an average particle size of 2.0 μm or less are prepared as starting materials. In addition, Al oxide powder having an average particle size of 2.0 μm or less, which is a starting material for the second subcomponent, is prepared as necessary. Furthermore, if necessary, Ho oxide powder, Eu oxide powder, Nd oxide powder, Yb oxide powder and Gd oxide powder having an average particle size of 2.0 μm or less, which are the starting materials of the third subcomponent Prepare the oxide powder.

After weighing these in a predetermined ratio, wet mixing is performed for a predetermined time using a ball mill or the like. It is also possible to use a mixture of various compounds, such as carbonates, oxalates, nitrates, hydroxides, organometallic compounds, etc., which are converted into the above-mentioned oxides by firing. Thereafter, the mixed powder is dried and then heat-treated in the air at 700° C. to 800° C. for 1 hour to 5 hours to obtain calcined powder as an accessory component. In addition, you may use the mixed powder which dried without heat-processing.

After that, the obtained calcined powder of the main component and the calcined powder of the subcomponent or the mixed powder of the subcomponent are mixed and pulverized to obtain the dielectric composition raw material. The average particle size of the dielectric composition raw material is arbitrary. For example, 0.5 μm to 2.0 μm.

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

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

When the dielectric layer paste is a water-based paint, a water-based vehicle obtained by dissolving a water-soluble binder or dispersant in water may be kneaded with the dielectric raw material. Any type of water-soluble binder may be used in the water-based vehicle. For example, polyvinyl alcohol, cellulose, water-soluble acrylic resin and the like can be used.

The internal electrode layer paste is prepared by kneading a conductive material made of the various conductive metals and alloys described above, or various oxides, organometallic compounds, resinates, etc., which will become the conductive material after firing, and the organic vehicle described above. Prepare.

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

The content of the organic vehicle in each of the pastes described above is not particularly limited, and the usual content may be, for example, about 1% to 5% by mass for the binder and about 10% to 50% by mass for the solvent. In addition, each paste may contain additives 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.

Any type of dispersant may be used. For example, surfactant-type dispersants and polymer-type dispersants can be used. The kind of plasticizer is arbitrary. For example, dioctyl phthalate and dibutyl phthalate can be used. Any type of dielectric material may be used. 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 dielectric layer paste and the internal electrode layer paste are printed and layered on a substrate such as PET, cut into a predetermined shape, and separated from the substrate to obtain a green chip.

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

The green chip may be subjected to binder removal treatment before firing. The binder removal treatment 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 for the binder removal treatment is air or a reducing atmosphere. In addition, in the binder removal process described above, any method may be used to humidify the N ₂ gas or the mixed gas. 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. When the holding temperature is within the above range, the material is sufficiently densified, preventing electrode breakage due to abnormal sintering of the internal electrode layers, and preventing diffusion of the material constituting the internal electrode layers, thereby suppressing deterioration in the rate of change in capacitance. be able to. Furthermore, coarsening of the main phase particles can be prevented, and high temperature load life can be improved.

The heating rate during firing is arbitrary. Preferably, it is 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 of the main phase particles, the temperature retention time during firing is preferably 0.5 hours. to 2.0 hours, and the cooling rate after firing is preferably 100° C./hour to 500° C./hour.

Moreover, it is preferable to use a humidified mixed gas of _N.sub.2 and _H.sub.2 and to perform the firing at an oxygen partial pressure of 10.sup. ^-2 to 10.sup. ^-6 Pa as the firing atmosphere.

After firing, the obtained capacitor element body is annealed as necessary. Annealing 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 the firing, and the holding temperature is 1000° C. or lower.

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

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

The dielectric composition according to the present embodiment has a high sintered density, a high relative dielectric constant, and a static temperature even when fired at a relatively low temperature of, for example, 1250° C. to 1350° C., preferably 1300° C. to 1350° C. Good temperature characteristics of capacitance. Although the reason for this is not necessarily certain, the following reasons are conceivable. When α, x and y are within the above ranges and the dielectric composition contains both Si and Mg in predetermined amounts, it is believed that the effect of lowering the sintering start temperature is obtained. It is believed that this makes it easier to obtain a high sintered density even when fired at a relatively low temperature, improves the dielectric constant, and improves the temperature characteristics of the capacitance.

[Second embodiment]
< Thin film capacitor >
FIG. 2 shows a schematic diagram of a thin film capacitor 11 according to this embodiment. The thin film capacitor 11 shown in FIG. 2 has a lower electrode 112 and a dielectric thin film 113 formed in this order on a substrate 111 and has an upper electrode 114 on the surface of the dielectric thin film 113 .

The material of the substrate 111 is not particularly limited, but using a silicon single crystal substrate as the substrate 111 is excellent in availability and cost. Nickel foil or copper foil can also be used as the substrate when flexibility is emphasized.

The materials of the lower electrode 112 and the upper electrode 114 are not particularly limited as long as they function as electrodes. Examples include platinum, silver, and nickel. The thickness of lower electrode 112 is not particularly limited, and is, for example, 0.01 to 10 μm. The thickness of the upper electrode 114 is also not particularly limited, and is, for example, 0.01 to 10 μm.

The composition and the crystal system of the main component of the dielectric composition forming the dielectric thin film 113 according to this embodiment are the same as those of the first embodiment.

Although the thickness of the dielectric thin film 113 is not particularly limited, it is preferably 10 nm to 1 μm.

Next, a method for manufacturing the thin film capacitor 11 will be described.

There is no particular limitation on the method of forming the thin film that will eventually become the dielectric thin film 113 . For example, vacuum deposition method, sputtering method, PLD method (pulsed laser deposition method), MO-CVD method (metal organic chemical vapor deposition method), MOD method (metal organic decomposition method), sol-gel method, CSD method (chemical solution deposition method) and the like are exemplified.

In addition, although the raw materials used for film formation may contain minute impurities and subcomponents, there is no particular problem as long as the amount is such that the performance of the thin film is not significantly impaired. In addition, the dielectric thin film 113 according to this embodiment may also contain minute impurities and subcomponents to the extent that the performance is not greatly impaired.

In this embodiment, a film forming method using the PLD method will be described.

First, a silicon single crystal substrate is prepared as the substrate 111 . Next, films of SiO ₂ , TiO _x and platinum are formed in this order on the silicon single crystal substrate to form the lower electrode 112 made of platinum. The method for forming the lower electrode 112 is not particularly limited. For example, a sputtering method, a CVD method, and the like can be used.

Next, a dielectric thin film 113 is formed on the lower electrode 112 by the PLD method. Alternatively, a metal mask may be used to partially expose the lower electrode 112 to form a region where the thin film is not partially formed.

In the PLD method, first, a target containing constituent elements of the desired dielectric thin film 113 is placed in a deposition chamber. Next, the surface of the target is irradiated with a pulsed laser. The strong energy of the pulsed laser instantly vaporizes the surface of the target. Then, the dielectric thin film 113 is formed by depositing the evaporated material on the substrate arranged so as to face the target.

The type of the target is not particularly limited, and a metal oxide sintered body containing constituent elements of the dielectric thin film 113 to be produced, as well as an alloy or the like can be used. In addition, although it is preferable that each element is evenly distributed in the target, the distribution may be varied as long as the quality of the obtained dielectric thin film 113 is not affected.

The number of targets does not necessarily have to be one, and a plurality of targets containing some of the constituent elements of the dielectric thin film 113 may be prepared and used for film formation. There is no restriction on the shape of the target, and the target may have a shape suitable for the film forming apparatus to be used.

Further, in the PLD method, it is preferable to heat the substrate 111 with an infrared laser during film formation in order to crystallize the dielectric thin film 113 to be formed. The heating temperature of the substrate 111 varies depending on the constituent elements and composition of the dielectric thin film 113 and the substrate 111. For example, the film is formed by heating to 600.degree. C. to 800.degree. By setting the temperature of the substrate 111 to an appropriate temperature, the dielectric thin film 113 can be easily crystallized, and the occurrence of cracks during cooling can be prevented.

Finally, by forming the upper electrode 114 on the dielectric thin film 113, the thin film capacitor 11 can be manufactured. The material of the upper electrode 114 is not particularly limited, and silver, gold, copper, or the like can be used. Also, the method of forming the upper electrode 114 is not particularly limited. For example, it can be formed by vapor deposition or sputtering.

Although the embodiments of the present invention have been described above, the present invention is by no means limited to such embodiments, and can of course be implemented in various manners without departing from the gist of the present invention. .

In the above-described embodiment, the case where the electronic component according to the present invention is a multilayer ceramic capacitor has been described, but the electronic component according to the present invention is not limited to the multilayer ceramic capacitor, and the electronic component having the dielectric composition described above. Anything is fine.

For example, it may be a single-plate ceramic capacitor in which a pair of electrodes are formed on a single-layer dielectric substrate made of the dielectric composition described above.

Further, the electronic component according to the present invention may be a filter, a diplexer, a resonator, an oscillator, an antenna, etc., in addition to the capacitor.

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

(Experimental example 1)
First, powders 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 were prepared as starting raw materials for the main components. The main component BaαLa{Ti _{(1.00-x) Zrx} } _2.00 {Nb _(1.00-y) Tay _{} 3.00O13.00 +} α contained in the finally obtained dielectric composition is shown in Tables 1 to 3. These raw materials were weighed so as to satisfy α, x and y.

Thereafter, ethanol was used as a dispersion medium and wet-mixed by a ball mill for 24 hours. After that, the obtained mixture was dried to obtain a mixed raw material powder. After that, heat treatment was performed in the atmosphere at a holding temperature of 900° C. for a holding time of 2 hours to obtain a calcined powder of the main component.

Next, powders of MgO and SiO ₂ were prepared as starting materials for the first subcomponent. Al ₂ O ₃ was prepared as a starting material for the second subcomponent. Powders of Ho ₂ O ₃ , Eu ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ and Gd ₂ O ₃ were prepared as starting materials for the third subcomponent.

The average particle size of the starting material of the first subcomponent, the starting material of the second subcomponent and the starting material of the third subcomponent was 0.2 μm or more and 2.0 μm or less.

These starting materials were weighed so as to obtain the compounding ratios shown in Tables 1 to 3. The contents of the first to third subcomponents shown in Tables 1 to 3 are the contents in terms of predetermined oxides per 100 mol parts of the main component.

After that, using ethanol as a dispersion medium, the starting materials of each subcomponent were wet-mixed by a ball mill for 24 hours. After that, the obtained mixture was dried to obtain a mixed powder. After that, heat treatment was performed in the atmosphere at a holding temperature of 800° C. for a holding time of 2 hours to obtain a calcined powder as an accessory component.

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

Ni with an average particle size of 0.2 μm, an Al oxide with an average particle size of 0.1 μm or less, and an Si oxide with an average particle size of 0.1 μm or less are prepared as raw materials for the internal electrode layers, Al and Si were weighed and mixed so that the total amount of Al and Si was 5% by mass with respect to Ni. After that, it was heat-treated in a humidified mixed gas of N ₂ and H ₂ at 1200° C. or higher, and pulverized using a ball mill or the like to prepare a raw material powder having an average particle size of 0.20 μm.

100 parts by mass of the raw material powder, 30 parts by mass of an organic vehicle (a solution of 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 a triple roll to form a paste, and an internal electrode is prepared. A layer paste was obtained.

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

Next, the resulting green chip was subjected to binder removal treatment, firing, and annealing to obtain a laminated ceramic fired body. The conditions for binder removal treatment, firing and annealing are as follows. A wetter was used to humidify the atmospheric gas in the binder removal treatment, firing, and annealing treatment.

(Binder removal treatment)
Heating rate: 100°C/hour Holding temperature: 400°C
Temperature holding time: 8.0 hours Atmospheric gas: mixed gas of humidified _N2 and _H2

(firing)
Heating 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 _N2 and _H2 Oxygen partial pressure: 10 ^-5 to 10 ^-9 Pa

(annealing treatment)
Holding temperature: 800° C. to 1000° C. Temperature holding time: 2.0 hours Heating and cooling rate: 200° C./hour Atmospheric gas: Humidified N ₂ gas

The dielectric layer (dielectric composition) of each laminated ceramic sintered body obtained was subjected to composition analysis using ICP emission spectrometry, and the composition was substantially the same as the composition shown in Tables 1 to 3. It was confirmed that 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 the end face of the obtained laminated ceramic sintered body was polished by sandblasting, an In—Ga eutectic alloy was applied as an external electrode, and each laminated ceramic capacitor sample having the same shape as the laminated ceramic capacitor shown in FIG. 1 was obtained. . Each of the obtained laminated ceramic capacitor samples had a size of 3.2 mm × 1.6 mm × 1.2 mm. The number of layers was 50 layers.

The sintered density, dielectric constant, temperature change rate of capacitance, resistivity, DC withstand voltage and high temperature load life of the obtained laminated ceramic capacitor samples were measured and evaluated by the methods shown below. 3.

[Sintered density]
The sintered density of the dielectric composition was measured as follows. First, the volume V of the dielectric composition was calculated. Subsequently, the mass M of the disk-shaped dielectric composition was measured, and the sintered density of the dielectric composition was obtained by calculating M/V. The results are shown in Tables 1-3.

[Dielectric constant at 250°C]
A digital LCR meter (YHP 4284A) was used to measure the capacitance of the multilayer ceramic capacitor sample at 250° C. by inputting a signal with a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms. Then, the dielectric constant (no 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. A higher dielectric constant is preferable, and in this example, 680 or more was judged to be good.

[Temperature change rate of capacitance]
A capacitor sample of the laminated ceramic capacitor was placed in a thermostat 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, the rate of change (ΔC T /C ₂₅ (%)) of the capacitance (C _T ) at temperature T (° C.) with respect to the capacitance ( _{C 25} ) at +25° C. is given by ΔC _T /C ₂₅ ={ (C _T -C ₂₅ )/C ₂₅ }×100. The rate of change in capacitance was measured at T = -55°C and T = 250°C. In this embodiment, when the temperature change rate of capacitance is within the range of ±15% when T=−55° C. and T=250° C., the temperature characteristic of capacitance is considered to be good, and ±10%. %, the temperature characteristic of the capacitance was judged to be better.

[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 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 the insulation resistance, the electrode area of the capacitor sample, and the thickness of the dielectric layer. A higher specific resistance is preferable.

From Tables 1 to 3, α is 2.05 ≤ α ≤ 2.25, x is 0.40 ≤ x ≤ 1.00, y is 0.05 ≤ y ≤ 0.85, and CMg /CSi is 0.75 ≤ CMg/CSi ≤ 2.0, and CMg + CSi is 15 ≤ CMg + CSi ≤ 30 (sample numbers 4 to 8, 11 to 13, 15 to 18, 22 to 26, 30, 31, 33, 37-58) have a sintered density of 5.60 g/cm ³ or more, a dielectric constant of 680 or more, and a temperature change rate of capacitance within the range of ±15%. did it.

From Table 3, when CAl is in the range of 2.5 to 10 (sample numbers 39 to 42, 44 to 58), the specific resistance is 3.2 × 10 ¹¹ Ωm or more, and the capacitance temperature It was confirmed that the rate of change was within the range of ±10%.

From Table 3, when at least one selected from the group consisting of CHo, CEu, CNd, CYb and CGd is within the range of 2.5 to 10 (sample numbers 44 to 58), the specific resistance is 5.5 × It was confirmed to be 10 ¹¹ Ωm or more.

(Experimental example 2)
A multilayer ceramic capacitor sample was produced in the same manner as in Experimental Example 1, except that the composition of the main component and the first subcomponent was as shown in Table 4, and the firing temperature was 1300°C or 1350°C, and various characteristics were evaluated. did. Table 4 shows the results. It should be noted that the temperature change rate of relative permittivity, specific resistance and capacitance shown in Table 4 are measured values of multilayer ceramic capacitor samples obtained at a sintering temperature of 1350°C.

3 is a graph for each sample shown in Table 4. FIG. The x-axis of FIG. 3 indicates the firing temperature [° C.], and the y-axis indicates the sintered density [g/cm ³ ]. In FIG. 3, ○ indicates sample number 61, ◆ indicates sample number 62, x indicates sample number 63, ● indicates sample number 64, and ▲ indicates sample number 65. , ◇ indicates the sample number 66, and ▪ indicates the sample number 67.

From Table 4 and FIG. 3, α is 2.05 ≤ α ≤ 2.25, x is 0.40 ≤ x ≤ 1.00, y is 0.05 ≤ y ≤ 0.85, CMg /CSi is 0.75≤CMg/CSi≤2.0 and CMg+CSi is 15≤CMg+CSi≤30 (sample numbers 64 to 67), the firing temperature was not only 1350°C, but also 1300°C. It was confirmed that a high sintered density can be obtained even in the case of

(Experimental example 3)
A multilayer ceramic capacitor sample was produced in the same manner as Sample No. 6 except that the type of rare earth element was as shown in Table 5, and various characteristics were evaluated. Results are shown in Table 5 and FIG.

From Table 5, it was confirmed that even if the rare earth element R is changed to Sm, Dy, Tb, Yb or Nd, the same effect as when the rare earth element R is La is obtained.

DESCRIPTION OF SYMBOLS 1... Laminated ceramic capacitor 2... Dielectric layer 3... Internal electrode layer 4... External electrode 10... Capacitor element main body 11... Thin film capacitor 111... Substrate 112... Lower electrode 113... Polycrystalline dielectric thin film 114... Upper electrode

Claims (6)

including a main component and a first subcomponent,
The main component is a tungsten bronze type composite oxide represented by BaαR {Ti _(1.00-x) Zr _x } _2.00 {Nb _(1.00-y) Ta _y } _3.00 O _13.00+ α,
The R is a rare earth element,
The α is 2.05≦α≦2.25,
The x is 0.40 ≤ x ≤ 1.00,
The y is 0.05 ≤ y ≤ 0.85,
The first subcomponent is Mg and Si,
The content of Si in terms of SiO ₂ with respect to 100 mol parts of the main component in the dielectric composition is defined as CSi mol parts,
When the content of Mg in terms of MgO with respect to 100 mol parts of the main component in the dielectric composition is defined as CMg mol parts,
CMg/CSi is 0.75≦CMg/CSi≦2.0,
A dielectric composition wherein CMg+CSi is 15≦CMg+CSi≦30. The dielectric composition comprises a second subcomponent,
the second subcomponent is Al,
When the content of Al in terms of Al ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CAl mol parts,
2. The dielectric composition of claim 1, wherein CA1 is in the range of 2.5-10. The dielectric composition comprises a third subcomponent,
the third subcomponent is at least one selected from the group consisting of Ho, Eu, Nd, Yb and Gd;
The content of Ho in terms of Ho ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CHo mol parts,
The content of Eu in terms of Eu ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CEu mol parts,
The content of Nd in terms of Nd ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CNd mol parts,
The content of Yb in terms of Yb ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is defined as CYb mol parts,
When the content of Gd in terms of Gd ₂ O ₃ with respect to 100 mol parts of the main component in the dielectric composition is CGd mol parts,
3. The dielectric composition according to claim 1, wherein at least one selected from the group consisting of CHo, CEu, CNd, CYb and CGd is within the range of 2.5-10. 4. The dielectric composition according to any one of claims 1 to 3, wherein said R is La. An electronic component comprising the dielectric composition according to any one of claims 1 to 4. A laminated electronic component in which dielectric layers and internal electrode layers are alternately laminated,
A multilayer electronic component, wherein the dielectric layer is the dielectric composition according to any one of claims 1 to 4.

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