Dielectric composition and electronic component

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 Mn 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 Mn in terms of MnO based on 100 molar parts of the main component in the dielectric composition is defined as CMn molar parts, CMn / CSi is 0.25≤CMn / CSi≤3.5 and CMn+CSi is 6.5≤CMn+CSi≤40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a dielectric composition and an electronic component. [Background technology]

[0002] Patent Document 1 describes a compound whose main component is the chemical formula Ba α R(Ti 1.00-x Zr x ) 2.00 (Nb 1.00-y Ta y ) 3.00 O 13.00+α and a dielectric composition containing V, W, and Si and / or Ge as auxiliary components.

[0003] In recent years, there has been a demand for a dielectric composition containing the above-mentioned main components that can achieve a higher sintered density even when fired at a low temperature. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6922701 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dielectric composition which has a high sintered density even when fired at a relatively low temperature, a high dielectric constant, and a good temperature characteristic of capacitance. [Means for solving the problem]

[0006] The dielectric composition according to the present invention comprises a main component and a first subcomponent, The main component is Ba α R{Ti (1.00-x) Zr x} 2.00 {Nb (1.00-y) Tay} 3.00 O 13.00+α It is a tungsten bronze type composite oxide represented by wherein 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 minor component is Mn and Si, The content of Si in the dielectric composition in terms of SiO2 relative to 100 parts by mole of the main component is defined as CSi parts by mole, When the content of Mn in terms of MnO relative to 100 parts by mole of the main component in the dielectric composition is expressed as Cm parts by mole, CMn / CSi is 0.25≦CMn / CSi≦3.5, CMn+CSi is 6.5≦CMn+CSi≦40.

[0007] The dielectric composition according to the present invention has a high sintered density, a high dielectric constant, and good temperature characteristics of capacitance, even when fired at a relatively low temperature. The reasons for this are not entirely clear, but the following is thought to be the cause. It is believed that the effect of lowering the sintering start temperature is achieved by having α, x, and y within the above ranges and the dielectric composition contain predetermined amounts of both Si and Mn. This makes it easier to obtain a high sintered density even when fired at a relatively low temperature, and it is thought that the dielectric constant is improved and the temperature characteristics of capacitance are also good.

[0008] As described above, the dielectric composition according to the present embodiment exhibits excellent characteristics in the high temperature range, and therefore can be suitably used in the operating temperature range (-55°C to 250°C) of SiC and GaN power devices. In addition, the dielectric composition can be suitably used as electronic components for noise removal in harsh environments such as the engine compartment of an automobile.

[0009] The dielectric composition according to the present invention preferably contains a second subcomponent, the second subcomponent is at least one selected from the group consisting of Mg and Al, the content of Mg in terms of MgO relative to 100 parts by mole of the main component in the dielectric composition is defined as CMg parts by mole, When the content of Al in terms of Al2O3 relative to 100 parts by mole of the main component in the dielectric composition is expressed as CAl parts by mole, It is preferable that at least one selected from the group consisting of CMg and CAl is within the range of 2.5-10.

[0010] By including the second subcomponent in the dielectric composition within the above range, the sintering initiation temperature is further reduced. This results in a further improvement in sintered density and a better temperature characteristic of capacitance. Furthermore, by including the second subcomponent in the dielectric composition within the above range, the effect of improving reduction resistance is obtained. As a result, the resistivity is improved.

[0011] The dielectric composition according to the present invention preferably contains a third subcomponent, the third minor component is at least one selected from the group consisting of Ho, Eu, Nd, Yb, and Gd; The content of Ho in the dielectric composition calculated as Ho2O3 relative to 100 parts by mole of the main component is defined as CHo parts by mole, The content of Eu in the dielectric composition calculated as Eu2O3 relative to 100 molar parts of the main component is defined as CEu molar parts, The content of Nd in the dielectric composition calculated as NdO relative to 100 parts by mole of the main component is defined as CNd parts by mole, The content of Yb in the dielectric composition calculated as YbO3 relative to 100 parts by mole of the main component is defined as CYb parts by mole, When the content of Gd in terms of Gd2O3 relative to 100 parts by mole of the main component in the dielectric composition is expressed as Cg parts by mole, It is preferable that at least one selected from the group consisting of CHo, CEu, CNd, CYb and CGd is included within the range of 2.5 to 10.

[0012] By including the third subcomponent in the dielectric composition within the above range, the effect of improving reduction resistance can be further obtained, resulting in a further improvement in resistivity.

[0013] It is preferable that R is La.

[0014] Moreover, an electronic device according to the present invention comprises the above-mentioned dielectric composition.

[0015] Furthermore, a laminated electronic component according to the present invention is a laminated electronic component in which dielectric layers and internal electrode layers are alternately laminated, The dielectric layer is the above-described dielectric composition. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of a thin film capacitor according to one embodiment of the present invention. [Figure 3] FIG. 3 is a graph relating to an example of the present invention and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0017] [First embodiment] < Multilayer ceramic capacitors > The multilayer ceramic capacitor 1, which is one type of multilayer electronic component according to this embodiment, has a capacitor element body 10 configured such that dielectric layers 2 and internal electrode layers 3 are alternately laminated.

[0018] A pair of external electrodes 4 are formed on both ends of the capacitor element body 10 and are electrically connected to the internal electrode layers 3 alternately arranged inside the capacitor element body 10 .

[0019] The capacitor element body 10 may have any shape, but is usually rectangular. Its dimensions may also be any, and may be set to an appropriate size depending on the application. The portion where the dielectric layers 2 and the internal electrode layers 3 are alternately stacked is referred to as the laminated portion.

[0020] The internal electrode layers 3 are laminated so that their ends are alternately exposed on the surfaces of two opposing end faces of the capacitor element body 10. A pair of external electrodes 4 are formed on both end faces 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.

[0021] 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.

[0022] The number of laminated dielectric layers 2 is arbitrary, but is preferably 20 or more, and more preferably 50 or more.

[0023] The type of conductive material contained in the internal electrode layer 3 is arbitrary. Ni, Ni-based alloy, Cu or Cu-based alloy is preferable. Ni or Ni-based alloy is more preferable. Even more preferable is that the main component of the internal electrode layer 3 is Ni or Ni-based alloy, and the secondary component contains one or more selected from Al, Si, Li, Cr and Fe. The main component of the internal electrode layer 3 refers to a component contained in an amount of 85 mass% or more of the entire internal electrode layer 3.

[0024] By using Ni or a Ni-based alloy as the main component of the internal electrode layers 3 and containing one or more selected from Al, Si, Li, Cr, and Fe as secondary components, the Ni contained in the internal electrode layers 3 is less likely to oxidize. As a result, even when the multilayer ceramic capacitor 1 is continuously used at a high temperature of about 250°C, deterioration of the continuity and conductivity due to oxidation of the internal electrode layers 3 is less likely to occur.

[0025] The internal electrode layer 3 may contain various trace components such as P in an amount of about 0.1 mass % or less. The internal electrode layer 3 may be formed using a commercially available electrode paste. The thickness of the internal electrode layer 3 may be determined appropriately depending on the application, etc.

[0026] Any conductive material may be contained in the external electrodes 4. 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 electrodes 4 may be determined appropriately depending on the application, etc., but is usually preferably about 10 to 50 μm.

[0027] Next, the dielectric composition constituting the dielectric layer 2 according to this embodiment will be described.

[0028] The dielectric composition according to this embodiment is a composition containing Ba as the main component. α R{Ti (1.00-x) Zr x} 2.00 {Nb (1.00-y) Ta y} 3.00 O 13.00+α It is a tungsten bronze type composite oxide represented by the formula:

[0029] R is a rare earth element. The type of R is arbitrary, but it is preferable to use La as R. By using La as R, it is easier to obtain (uniform sintered particles). Furthermore, the content of La relative to the entire R is preferably 50 mol % or more, and it is most preferable that R consists essentially of La only. R consisting essentially of La only means that the content of La relative to the entire R is 95 mol % or more.

[0030] α means the content of Ba. In this embodiment, α is in the range of 2.05≦α≦2.25, and preferably 2.10≦α≦2.20.

[0031] x means the content of Zr. In this embodiment, x satisfies 0.40≦x≦1.00, and preferably 0.60≦x≦0.80.

[0032] y represents the content of Ta. In this embodiment, y satisfies 0.05≦y≦0.85, and preferably 0.30≦y≦0.80.

[0033] The dielectric composition according to this embodiment includes a first minor component, which is Mn and Si.

[0034] The Si content in SiO2 equivalent per 100 molar parts of the main component in the dielectric composition is defined as CSi molar parts, and the Mn content in MnO equivalent per 100 molar parts of the main component in the dielectric composition is defined as CMn molar parts.

[0035] In this embodiment, CMn / CSi satisfies 0.25≦CMn / CSi≦3.5.

[0036] In addition, CMn+CSi is 6.5≦CMn+CSi≦40.

[0037] The dielectric composition according to the present invention preferably contains a second subcomponent, which is at least one selected from the group consisting of Mg and Al. That is, the second subcomponent may be of only one type, or may be a combination of two types.

[0038] The content of Mg in terms of MgO relative to 100 molar parts of the main component in the dielectric composition is defined as CMg molar parts, and the content of Al in terms of Al2O3 relative to 100 molar parts of the main component in the dielectric composition is defined as CAl molar parts.

[0039] In this embodiment, it is preferable that at least one selected from the group consisting of CMg and CAl is within the range of 2.5-10.

[0040] 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 a single type or a combination of two or more types.

[0041] The content of Ho in terms of Ho2O3 per 100 molar parts of the main component in the dielectric composition is defined as CHo molar parts. The content of Eu in terms of Eu2O3 per 100 molar parts of the main component in the dielectric composition is defined as CEu molar parts. The content of Nd in terms of Nd2O3 per 100 molar parts of the main component in the dielectric composition is defined as CNd molar parts. The content of Yb in terms of Yb2O3 per 100 molar parts of the main component in the dielectric composition is defined as CYb molar parts. The content of Gd in terms of Gd2O3 per 100 molar parts of the main component in the dielectric composition is defined as CGd molar parts.

[0042] In this embodiment, it is preferable that at least one selected from the group consisting of CHo, CEu, CNd, CYb, and CGd is included within the range of 2.5 to 10.

[0043] The dielectric composition according to this embodiment is composed of main phase particles mainly made of the main component and grain boundaries existing between the main phase particles. The proportion of the main component in the main phase particles is, for example, 90 mass% or more on average. The particle size of the main phase particles is also optional. For example, it may be 0.5 μm or more and 2.0 μm or less on average.

[0044] In this embodiment, the first to third subcomponents may be dissolved in the main phase grains, or may be present at the grain boundaries without being dissolved in the main phase grains.

[0045] Furthermore, the dielectric composition according to this embodiment may contain trace impurities or subcomponents other than the first to third subcomponents, as long as they do not significantly deteriorate the rate of change of capacitance with temperature. For example, Cr, Zn, Cu, Ga, etc. may be contained in the dielectric composition. Therefore, the content of the main component relative to the entire dielectric composition is arbitrary. For example, the amount of elements other than oxygen constituting the main component may be 65 mol % or more and 94.6 mol % or less of all elements other than oxygen constituting the dielectric composition.

[0046] Next, an example of a method for manufacturing the multilayer ceramic capacitor 1 of this embodiment will be described. In the manufacturing method below, the case where R is La will be described.

[0047] The multilayer ceramic capacitor 1 of this embodiment is manufactured in the same manner as conventional multilayer ceramic capacitors, by preparing a green chip by a normal printing method or sheet method using a paste, firing the green chip, and then applying external electrodes and firing the chip. The manufacturing method will be specifically described below.

[0048] First, calcined powders of the main components are prepared. Powders of oxides and mixtures primarily 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. Various compounds that become the oxides mentioned above upon firing, such as carbonates, oxalates, nitrates, hydroxides, and organometallic compounds, can also be appropriately selected and mixed for use. After weighing out the starting materials in a predetermined ratio, they are wet-mixed for a predetermined time using a ball mill or the like. After drying the mixed powder, they are heat-treated in air at 1000°C or less to obtain calcined powders of the main components.

[0049] Next, calcined powders of the subcomponents are prepared. For the first subcomponent, Si oxide powder and Mn oxide powder with an average particle size of 2.0 μm or less are prepared as starting materials. Furthermore, as necessary, Mg oxide powder and Al oxide powder with an average particle size of 2.0 μm or less are prepared as starting materials for the second subcomponent. Furthermore, as necessary, Ho oxide powder, Eu oxide powder, Nd oxide powder, Yb oxide powder, and Gd oxide powder with an average particle size of 2.0 μm or less are prepared as starting materials for the third subcomponent.

[0050] These ingredients are weighed in a predetermined ratio and then wet-mixed for a predetermined time using a ball mill or the like. Alternatively, various compounds that become the oxides mentioned above upon firing, such as carbonates, oxalates, nitrates, hydroxides, and organometallic compounds, can be appropriately selected and mixed for use. The mixed powder is then dried and heat-treated in air at 700°C to 800°C for 1 to 5 hours to obtain a calcined powder of the minor components. Alternatively, the dried mixed powder can be used without heat treatment.

[0051] The calcined powder of the main component and the calcined powder of the subcomponent or the mixed powder of the subcomponents are then mixed and crushed to obtain a dielectric composition raw material. The average particle size of the dielectric composition raw material is optional, for example, 0.5 μm to 2.0 μm.

[0052] 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 in which the dielectric composition raw material is kneaded with an organic vehicle, or may be a water-based paint.

[0053] The organic vehicle is a binder dissolved in an organic solvent. The type of binder used in the organic vehicle is arbitrary 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. Depending on the method for manufacturing the multilayer ceramic capacitor (e.g., printing method, sheet method, etc.), it may be appropriately selected from various organic solvents, such as terpineol, butyl carbitol, and acetone.

[0054] When the dielectric layer paste is a water-based paint, the dielectric material is kneaded with an aqueous vehicle in which a water-soluble binder and dispersant are dissolved in water. Any type of water-soluble binder can be used in the aqueous vehicle. For example, polyvinyl alcohol, cellulose, water-soluble acrylic resin, etc. can be used.

[0055] The internal electrode layer paste is prepared by kneading the conductive material made of the various conductive metals or alloys described above, or various oxides, organometallic compounds, resinates, etc. that become the conductive material after firing, with the organic vehicle described above.

[0056] The external electrode paste can be prepared in the same manner as the internal electrode layer paste described above.

[0057] There are no particular restrictions on the content of the organic vehicle in each of the above pastes, and typical contents, such as about 1% to 5% by mass for the binder and about 10% to 50% by mass for the solvent, may be used. Furthermore, each paste may contain additives selected from various dispersants, plasticizers, dielectric materials, insulating materials, etc., as needed. The total content of these is preferably 10% by mass or less.

[0058] Any type of dispersant can be used. For example, surfactant-type dispersants and polymer-type dispersants can be used. Any type of plasticizer can be used. For example, dioctyl phthalate and dibutyl phthalate can be used. Any type of dielectric material can be used. For example, BaTiO3-based and CaZrO3-based materials can be used. Any type of insulator material can be used. For example, Al2O3 and SiO2 can be used.

[0059] When the printing method is used, the dielectric layer paste and the internal electrode layer paste are printed and laminated on a substrate such as PET, cut into a predetermined shape, and then peeled off from the substrate to form a green chip.

[0060] When the sheet method is used, a green sheet is formed using a dielectric layer paste, and then the internal electrode layer paste is printed on the green sheet, and these are then laminated to form a green chip.

[0061] Before firing, the green chip may be subjected to a binder removal treatment. The conditions for the binder removal treatment 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 hours to 24 hours. The atmosphere for the binder removal treatment is air or a reducing atmosphere. In the binder removal treatment described above, the method for humidifying N2 gas or mixed gas 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.

[0062] The holding temperature during firing is optional. It is preferably 1100°C to 1400°C. By keeping the holding temperature within the above range, the internal electrode layers are sufficiently densified, preventing breaks in the electrodes due to abnormal sintering and preventing diffusion of the internal electrode layer constituent material, thereby suppressing deterioration in the rate of change of capacity. Furthermore, coarsening of main phase particles can be prevented, and high-temperature load life can be improved.

[0063] The temperature rising rate during firing is optional, and is preferably 200°C / hour to 5000°C / hour. The temperature holding time during firing and the cooling rate after firing are optional. In order to control the particle size distribution of the main phase particles after sintering to within the range of 0.5 μm to 5.0 μm and to suppress volume diffusion between the main phase particles, the temperature holding 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.

[0064] The firing atmosphere was a mixture of humidified N2 and H2 gases, with an oxygen partial pressure of 10 -2 ~10 -6 It is preferable to bake at 200 Pa.

[0065] After firing, the resulting capacitor element body is annealed as needed. The annealing conditions may be well-known. For example, it is preferable that the oxygen partial pressure during annealing is higher than that during firing, and that the holding temperature is 1000°C or less.

[0066] In the above manufacturing method, the binder removal treatment, firing and annealing treatment are carried out independently, but they may be carried out consecutively.

[0067] The capacitor element body obtained as described above is subjected to end surface polishing, for example, by barrel polishing or sandblasting, and then external electrode paste is applied and fired to form external electrodes 4. Then, if necessary, a coating layer is formed on the surface of the external electrodes 4 by plating or the like.

[0068] The dielectric composition according to this embodiment has a high sintered density, a high dielectric constant, and good temperature characteristics of capacitance, even when fired at a relatively low temperature, for example, 1250°C to 1350°C, preferably 1300°C to 1350°C. The reason for this is not entirely clear, but the following is thought to be the reason. It is believed that the effect of lowering the sintering start temperature is achieved by having α, x, and y within the above ranges and the dielectric composition containing predetermined amounts of both Si and Mn. This makes it easier to obtain a high sintered density even when fired at a relatively low temperature, and it is thought that the dielectric constant is improved and the temperature characteristics of capacitance are also good.

[0069] [Second embodiment] < thin film capacitor > A schematic diagram of a thin film capacitor 11 according to this embodiment is shown in Fig. 2. In the thin film capacitor 11 shown in Fig. 2, a lower electrode 112 and a dielectric thin film 113 are formed in this order on a substrate 111, and an upper electrode 114 is provided on the surface of the dielectric thin film 113.

[0070] There are no particular restrictions on the material of the substrate 111, but using a silicon single crystal substrate is easy to obtain and cost-effective as the substrate 111. When flexibility is important, nickel foil or copper foil can also be used as the substrate.

[0071] There are no particular limitations on the materials for the lower electrode 112 and the upper electrode 114, as long as they function as electrodes. Examples include platinum, silver, and nickel. There are no particular limitations on the thickness of the lower electrode 112, and it is, for example, 0.01 to 10 μm. There are also no particular limitations on the thickness of the upper electrode 114, and it is, for example, 0.01 to 10 μm.

[0072] The composition of the dielectric composition constituting the dielectric thin film 113 according to this embodiment and the crystal system of the main component are the same as those in the first embodiment.

[0073] There is no particular limitation on the thickness of the dielectric thin film 113, but it is preferably 10 nm to 1 μm.

[0074] Next, a method for manufacturing the thin film capacitor 11 will be described.

[0075] There are no particular limitations on the method for forming the thin film that will ultimately become the dielectric thin film 113. Examples include vacuum evaporation, sputtering, PLD (pulsed laser deposition), MO-CVD (metal organic chemical vapor deposition), MOD (metal organic decomposition), sol-gel, and CSD (chemical solution deposition).

[0076] Furthermore, the raw materials used in film formation may contain trace amounts of impurities or secondary components, but this is not a problem as long as the amounts do not significantly impair the performance of the thin film.Furthermore, the dielectric thin film 113 according to this embodiment may also contain trace amounts of impurities or secondary components to the extent that they do not significantly impair the performance.

[0077] In this embodiment, a film formation method using the PLD method will be described.

[0078] First, a silicon single crystal substrate is prepared as the substrate 111. Next, SiO2, TiO x Then, a film of platinum is formed on the lower electrode 112. There are no particular limitations on the method for forming the lower electrode 112. For example, sputtering or CVD may be used.

[0079] Next, a dielectric thin film 113 is formed by PLD on the lower electrode 112. Alternatively, a metal mask may be used to expose a portion of the lower electrode 112, forming an area where the thin film is not formed.

[0080] In the PLD method, first, a target containing the constituent elements of the desired dielectric thin film 113 is placed in a film formation chamber. Next, a pulsed laser is irradiated onto the surface of the target. The strong energy of the pulsed laser instantly evaporates the surface of the target. The evaporated material is then deposited on a substrate placed opposite the target to form the dielectric thin film 113.

[0081] There is no particular limitation on the type of target, and it is possible to use an alloy or the like in addition to a metal oxide sintered body containing the constituent elements of the dielectric thin film 113 to be produced. Furthermore, it is preferable that each element is distributed evenly in the target, but the distribution may vary within a range that does not affect the quality of the resulting dielectric thin film 113.

[0082] The number of targets does not necessarily have to be one, and it is also possible to prepare and use multiple targets containing some of the constituent elements of the dielectric thin film 113. There are also no limitations on the shape of the target, and it is sufficient if the shape is suitable for the film formation apparatus to be used.

[0083] Furthermore, when using 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. 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, but film formation is performed by heating to, for example, 600°C to 800°C. By maintaining the temperature of the substrate 111 at an appropriate temperature, the dielectric thin film 113 is more likely to crystallize and cracks that occur during cooling can be prevented.

[0084] Finally, the thin film capacitor 11 can be manufactured by forming the upper electrode 114 on the dielectric thin film 113. There is no particular limitation on the material of the upper electrode 114, and silver, gold, copper, etc. can be used. There is also no particular limitation on the method for forming the upper electrode 114. For example, it can be formed by vapor deposition or sputtering.

[0085] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that the present invention can be embodied in various different forms without departing from the spirit of the present invention.

[0086] In the above-described embodiment, the electronic component according to the present invention is described as a multilayer ceramic capacitor. However, the electronic component according to the present invention is not limited to a multilayer ceramic capacitor, and may be any electronic component having the above-described dielectric composition.

[0087] For example, it may be a single-plate ceramic capacitor in which a pair of electrodes is formed on a single-layer dielectric substrate made of the above-mentioned dielectric composition.

[0088] Furthermore, the electronic component according to the present invention may be a filter, a diplexer, a resonator, an oscillator, an antenna, or the like, in addition to a capacitor. [Example]

[0089] The present invention will be described in more detail below with reference to specific examples of the present invention, but the present invention is not limited to these examples.

[0090] (Experimental Example 1) First, powders of BaCO3, La(OH)3, TiO2, ZrO2, Ta2O5, and Nb2O5 with an average particle size of 1.0 μm or less were prepared as starting materials for the main components. α La{Ti (1.00-x) Zr x} 2.00 {Nb (1.00-y) Ta y} 3.00 O 13.00+α These raw materials were weighed so that the values ​​of α, x, and y shown in Tables 1 to 3 were satisfied.

[0091] The mixture was then wet-mixed for 24 hours in a ball mill using ethanol as a dispersion medium. The resulting mixture was then dried to obtain a mixed raw material powder. This was then heat-treated in air at a holding temperature of 900°C for 2 hours to obtain a calcined powder of the main component.

[0092] Next, MnO and SiO2 powders were prepared as starting materials for the first subcomponent, MgO and Al2O3 powders were prepared as starting materials for the second subcomponent, and Ho2O3, Eu2O3, Nd2O3, Yb2O3, and Gd2O3 powders were prepared as starting materials for the third subcomponent.

[0093] The starting material for the first subcomponent, the starting materials for the second subcomponent, and the third subcomponent had an average particle size of 0.2 μm or more and 2.0 μm or less.

[0094] These starting materials were weighed out to obtain the blending ratios shown in Tables 1 to 3. The contents of the first to third subcomponents shown in Tables 1 to 3 are expressed as the contents converted into predetermined oxides relative to 100 parts by mole of the main component.

[0095] The starting materials for each subcomponent were then wet-mixed for 24 hours in a ball mill using ethanol as a dispersion medium. The resulting mixture was then dried to obtain a mixed powder. This was then heat-treated in air at a holding temperature of 800°C for 2 hours to obtain a calcined powder of the subcomponents.

[0096] The calcined powders of the main and secondary components obtained by the above method were mixed and crushed to obtain a dielectric composition raw material. Next, 700 g of a solvent consisting of a toluene / ethanol solution (toluene:ethanol = 50:50 (weight ratio)), a plasticizer (dioctyl phthalate (DOP) (manufactured by J-Plus)), and a dispersant (Marialim AKM-0531 (manufactured by NOF Corp.)) mixed in a 90:6:4 (weight ratio) was added to 1,000 g of the dielectric composition raw material. The mixture was then dispersed for two hours using a basket mill to prepare a dielectric layer paste. In all examples and comparative examples, the viscosity of the dielectric layer paste was adjusted to approximately 200 cps. Specifically, the viscosity was adjusted by adding a small amount of toluene / ethanol solution.

[0097] As raw materials for the internal electrode layers, Ni with an average particle size of 0.2 μm, Al oxide with an average particle size of 0.1 μm or less, and Si oxide with an average particle size of 0.1 μm or less were prepared, and were weighed and mixed so that the total of Al and Si was 5 mass% relative to Ni. Then, the mixture was heat-treated in a humidified N2 and H2 mixed gas at 1200°C or higher, and crushed using a ball mill or the like to prepare raw material powder with an average particle size of 0.20 μm.

[0098] 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 were kneaded using a three-roll mill to form a paste, thereby obtaining a paste for the internal electrode layer.

[0099] The prepared dielectric layer paste was then applied to a 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 internal electrode layers was printed on the green sheet using the internal electrode layer paste. The green sheet was then peeled off from the PET film to produce a green sheet on which the internal electrode layers were printed in the predetermined pattern. Next, multiple green sheets on which the internal electrode layers were printed in the predetermined pattern were stacked and pressure-bonded to form a green laminate. Furthermore, the green laminate was cut into a predetermined shape to obtain a green chip.

[0100] The green chip was then subjected to binder removal, firing, and annealing to obtain a multilayer ceramic fired body. The conditions for the binder removal, firing, and annealing were as follows. A wetter was used to humidify the atmospheric gas during the binder removal, firing, and annealing processes.

[0101] (Debinding process) Heating rate: 100℃ / hour Holding temperature: 400℃ Temperature holding time: 8.0 hours Atmospheric gas: Humidified N2 and H2 mixed gas

[0102] (Firing) Heating rate: 500°C / hour Holding temperature: 1200℃~1350℃ Temperature holding time: 2.0 hours Cooling rate: 100℃ / hour Atmospheric gas: Humidified N2 and H2 mixed gas Oxygen partial pressure: 10 -5 ~10 -9 Pa

[0103] (annealing treatment) Holding temperature: 800℃~1000℃ Temperature holding time: 2.0 hours Temperature increase and decrease rate: 200°C / hour Atmospheric gas: Humidified N2 gas

[0104] The composition of the dielectric layer (dielectric composition) of each of the obtained multilayer ceramic sintered bodies was analyzed using ICP atomic emission spectroscopy, and it was confirmed that the composition was substantially the same as the composition shown in Tables 1 to 3. In addition, X-ray diffraction measurement was performed, and it was confirmed from the X-ray diffraction pattern that the dielectric layer had a tungsten bronze type crystal structure.

[0105] The end faces of the obtained multilayer ceramic sintered bodies were polished by sandblasting, and then an In-Ga eutectic alloy was applied as external electrodes to obtain multilayer ceramic capacitor samples with the same shape as the multilayer ceramic capacitor shown in Figure 1. The size of the obtained multilayer ceramic capacitor samples was 3.2 mm x 1.6 mm x 1.2 mm, with dielectric layer thicknesses of 7 μm, internal electrode layers of 2 μm, and 50 dielectric layers sandwiched between the internal electrode layers.

[0106] The sintered density, relative dielectric constant, temperature coefficient of capacitance, resistivity, DC withstand voltage and high temperature load life of the obtained multilayer ceramic capacitor samples were measured and evaluated by the methods described below. The results are shown in Tables 1 to 3.

[0107] [Sintered density] The sintered density of the dielectric composition was measured as follows: First, the volume V of the dielectric composition was calculated. Next, 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.

[0108] [Dielectric constant at 250℃] The capacitance of the multilayer ceramic capacitor samples was measured at 250°C using a digital LCR meter (YHP 4284A) with a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms. The dielectric constant (unitless) 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, a value of 700 or higher was considered to be good.

[0109] [Temperature change rate of capacitance] The multilayer ceramic capacitor sample was placed in a thermostatic chamber manufactured by Despatch, and the capacitance was measured at a measurement voltage of 1 Vrms in the temperature range of -55 to 250°C. The capacitance (C 25 ) vs. capacitance (C T ) change rate (ΔC T / C 25 (%)) and ΔC T / C 25 ={(C T -C 25 ) / C 25 The capacitance change rate was calculated using the formula:}×100. The capacitance change rate was measured when T=−55°C and when T=250°C. In this example, when the capacitance change rate with temperature was within ±15% when T=−55°C and when T=250°C, the capacitance was considered to have good temperature characteristics, and when it was within ±10%, the capacitance was considered to have better temperature characteristics.

[0110] [Resistivity at 250℃] The insulation resistance of the multilayer ceramic capacitor samples was measured at 250°C using a digital resistance meter (R8340 manufactured by ADVANTEST) under conditions of a measurement voltage of 350V (50V / μm) and a measurement time of 60 seconds. The specific resistance was calculated from the measured insulation resistance value, the electrode area of ​​the capacitor sample, and the thickness of the dielectric layer. A higher specific resistance is preferable.

[0111] [Table 1]

[0112] [Table 2]

[0113] [Table 3]

[0114] From Tables 1 to 3, when 2.05≦α≦2.25, 0.40≦x≦1.00, 0.05≦y≦0.85, 0.25≦CMn / CSi≦3.5, and CMn+CSi is 6.5≦CMn+CSi≦40 (sample numbers 4 to 8, 11 to 13, 15 to 18, 22 to 26, 30, 31, 33, and 37 to 62), the sintered density is 6.00 g / cm 3 It was confirmed that the relative dielectric constant was 700 or more and the temperature coefficient of capacitance was within the range of ±15%.

[0115] From Table 3, when at least one selected from the group consisting of CMg and CAl is within the range of 2.5 to 10 (sample numbers 39 to 44, 48 to 62), the resistivity is 3.3 × 10 11 It was confirmed that the capacitance was Ωm or more and that the temperature coefficient of capacitance was within the range of ±10%.

[0116] 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 48 to 62), the resistivity is 5.3 × 10 11 It was confirmed that the resistance was Ωm or more.

[0117] (Experimental Example 2) Multilayer ceramic capacitor samples were produced and their properties were evaluated in the same manner as in Experimental Example 1, except that the compositions of the main component and the first to third subcomponents were as shown in Tables 4 to 8 and the firing temperature was 1250° C., 1300° C., or 1350° C. The results are shown in Tables 4 to 8.

[0118] It should be noted that sample numbers 74, 81, 91, 101 and 111 have the same composition.

[0119] The relative permittivity, resistivity and temperature coefficient of capacitance shown in Tables 4 to 8 are measured values ​​of multilayer ceramic capacitor samples obtained at a firing temperature of 1350°C.

[0120] Figure 3 is a graph for each sample shown in Table 4. The x-axis of Figure 3 represents the firing temperature [°C], and the y-axis represents the sintered density [g / cm 3 3 indicates sample number 71, ◆ indicates sample number 72, × indicates sample number 73, ● indicates sample number 74, ▲ indicates sample number 75, and ◇ indicates sample number 76.

[0121] [Table 4]

[0122] [Table 5]

[0123] [Table 6]

[0124] [Table 7]

[0125] [Table 8]

[0126] From Table 4 and Figure 3, it was confirmed that when 2.05≦α≦2.25, 0.40≦x≦1.00, 0.05≦y≦0.85, 0.25≦CMn / CSi≦3.5, and CMn+CSi is 6.5≦CMn+CSi≦40 (sample numbers 73 to 76), a high sintered density can be obtained not only when the firing temperature is 1350°C, but also when the firing temperature is 1250°C or 1300°C.

[0127] Tables 5 to 7 also confirm that when 2.05≦α≦2.25, 0.40≦x≦1.00, 0.05≦y≦0.85, 0.25≦CMn / CSi≦3.5, and CMn+CSi is 6.5≦CMn+CSi≦40 (sample numbers 81 to 85, 91 to 95, 101 to 106, and 111 to 116), high sintered density can be obtained not only when the firing temperature is 1350°C, but also when the firing temperature is 1250°C or 1300°C.

[0128] (Experimental Example 3) Multilayer ceramic capacitor samples were prepared in the same manner as sample number 6, except that the types of rare earth elements were changed as shown in Table 9, and various characteristics were evaluated. The results are shown in Table 9.

[0129] [Table 9]

[0130] From Table 9, it was confirmed that even when the rare earth element R was changed to Sm, Dy, Tb, Yb or Nd, the same effect as when the rare earth element R was La was obtained. [Explanation of symbols]

[0131] 1. Multilayer ceramic capacitor 2... Dielectric layer 3… Internal electrode layer 4… External electrode 10... Capacitor element body 11... Thin film capacitor 111... Circuit board 112... Lower electrode 113... Polycrystalline dielectric thin film 114...Top electrode

Claims

1. A dielectric composition comprising a main component and a first subcomponent, The main component is BaαR{Ti (1.00-x) Zr x } 2.00 {Nb (1.00-y) Ta y } 3.00 It is a tungsten bronze type composite oxide expressed as O13.00+α, 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 minor component is Mn and Si, SiO relative to 100 molar parts of the main component in the dielectric composition 2 The Si content calculated as CSi molar parts is When the content of Mn in terms of MnO relative to 100 parts by mole of the main component in the dielectric composition is expressed as C₁₁₁ parts by mole, CMn / CSi is 0.25≦CMn / CSi≦3.5, A dielectric composition in which CMn+CSi satisfies 6.5≦CMn+CSi≦40.

2. The dielectric composition includes a second subcomponent, the second subcomponent is at least one selected from the group consisting of Mg and Al, The content of Mg in terms of MgO relative to 100 parts by mole of the main component in the dielectric composition is defined as CMg parts by mole, Al relative to 100 parts by mole of the main component in the dielectric composition 2 O 3 When the content of Al converted into CAl molar parts, 2. The dielectric composition according to claim 1, wherein the content of at least one selected from the group consisting of C Mg and C Al is within the range of 2.5 to 10.

3. The dielectric composition includes a third subcomponent, the third minor component is at least one selected from the group consisting of Ho, Eu, Nd, Yb, and Gd; Ho relative to 100 parts by mole of the main component in the dielectric composition 2 O 3 The content of Ho converted into CHO molar parts, Eu relative to 100 molar parts of the main component in the dielectric composition 2 O 3 The Eu content calculated as CEu molar parts is taken as CEu molar parts, Nd relative to 100 parts by mole of the main component in the dielectric composition 2 O 3 The content of Nd converted into CNd molar parts, Yb relative to 100 parts by mole of the main component in the dielectric composition 2 O 3 The content of Yb converted into CYb molar parts is taken as CYb molar parts, Gd relative to 100 parts by mole of the main component in the dielectric composition 2 O 3 When the converted Gd content is expressed as CGd molar 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 contained within the range of 2.5 to 10.

4. The dielectric composition according to any one of claims 1 to 3, wherein R is La.

5. An electronic component comprising the dielectric composition according to any one of claims 1 to 4.

6. A laminated electronic component in which dielectric layers and internal electrode layers are alternately laminated, A laminated electronic component, wherein the dielectric layer is made of the dielectric composition according to any one of claims 1 to 4.

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