JP2004217520A - Method for manufacturing dielectric porcelain composition and method for manufacturing electronic component containing dielectric layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer ceramic capacitor, which meets temperature characteristics of capacitance including the X7R characteristic (EIA Standard) and the B characteristic (EIAJ Standard), and which has lesser change in capacitance with time in a DC electric field, a long accelerated life of insulation resistance and lesser reduction in capacitance when a DC bias is applied, even if a dielectric layer is very thin with the thickness of 4 μm or smaller. <P>SOLUTION: The method for manufacturing a dielectric porcelain composition containing at least BaTiO<SB>3</SB>as a main ingredient, a second auxiliary ingredient expressed by (Ba,Ca)<SB>x</SB>SiO<SB>2+x</SB>( provided that x=0.8-1.2), and other auxiliary ingredients comprises: a step of mixing the main ingredient with at least a part of the other auxiliary ingredients than the second auxiliary ingredient to obtain a mixed powder before calcination; a step of calcining the mixed powder to prepare a calcined powder; and a step of mixing the calcined powder with at least the second auxiliary ingredient so that the ratio of each of these auxiliary ingredients to the main ingredient of BaTiO3 is adjusted to a prescribed molar ratio, to manufacture the dielectric porcelain composition. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a method for producing a dielectric ceramic composition and a method for producing a dielectric layer-containing electronic component such as a multilayer ceramic capacitor.

  2. Description of the Related Art Multilayer ceramic capacitors are widely used as small, large-capacity, high-reliability electronic components, and the number used in electric devices and electronic devices is large. In recent years, with the miniaturization and high performance of devices, demands for further miniaturization, large capacity, low cost, and high reliability of multilayer ceramic capacitors have become more and more severe.

  A multilayer ceramic capacitor is usually manufactured by laminating a paste of an internal electrode and a slurry (paste) of a dielectric by a sheet method or a printing method, and firing. In general, Pd and Pd alloy have been used for such internal electrodes. However, since Pd is expensive, relatively inexpensive Ni or Ni alloy is being used. By the way, when the internal electrode is formed of Ni or a Ni alloy, there is a problem that the electrode is oxidized when firing in the air. Therefore, in general, after the binder is removed, firing is performed at an oxygen partial pressure lower than the equilibrium oxygen partial pressure of Ni and NiO, and then the dielectric layer is re-oxidized by heat treatment (Japanese Patent Application Laid-Open No. 03-133116; No. 2,877,746).

However, when firing in a reducing atmosphere, the dielectric layer is reduced and the specific resistance is reduced. Therefore, a reduction-resistant dielectric material that is not reduced even when fired in a reducing atmosphere has been proposed (I. Burn, et al., "High Resistivity BaTiO ₃ Ceramics Sintered in CO-CO ₂ Atmospheres" J. Am. Mater. Sci., 10, 633 (1975); Y. Sakabe, et al., "High-Dielectric Constant Ceramics for Base Metal Monolithic Capacitors, 20.P.p.20. 1981)).

  However, multilayer ceramic capacitors using these reduction-resistant dielectric materials have a problem that the high-temperature accelerated life of the insulation resistance (IR) is short and the reliability is low. In addition, there is a problem that the relative permittivity of the dielectric material decreases with time, which is particularly remarkable under a DC electric field. When the thickness of the dielectric layer is reduced in order to reduce the size and increase the capacity of the multilayer ceramic capacitor, the electric field intensity applied to the dielectric layer when a DC voltage is applied increases. For this reason, the change with time of the relative dielectric constant becomes extremely large.

By the way, in a standard called the X7R characteristic defined in the EIA standard, the rate of change of the capacitance is defined to be within ± 15% (reference temperature 25 ° C.) between −55 ° C. and 125 ° C. As a dielectric material satisfying the X7R characteristic, for example, a BaTiO ₃ + SrTiO ₃ + MnO-based composition disclosed in JP-A-61-36170 is known. However, this composition has a large change with time in the capacity under a DC electric field. For example, when a DC electric field of 50 V is applied at 40 ° C. for 1000 hours, the rate of change of the capacity becomes about −10 to −30%, and the X7R characteristic Cannot be satisfied.

  Further, in a standard called the B characteristic (EIAJ standard), which is a temperature characteristic of the capacitance, the temperature is set within a range of −25 to 85 ° C. within ± 10% (a reference temperature of 20 ° C.).

In addition to this, as the reduction resistant dielectric ceramic composition, BaTiO ₃ + MnO + MgO disclosed in JP-A-57-71866, it is disclosed in JP-A-61-250905 (Ba _{1 -x Sr x O) a Ti 1} -y Zr y O 2 + α ((1-z) MnO + zCoO) + β ((1-t) A 2 O 5 + tL 2 O 3) + wSiO 2 ( provided that, A = Nb, Ta , V; L = Y or a rare earth element), barium titanate was added _Ba a _Ca 1-a SiO ₃ disclosed in JP-a-2-83256, and the like.

  However, in any of these dielectric ceramic compositions, when the thickness of the dielectric layer is an ultra-thin layer of, for example, 4 μm or less, the temperature characteristics of the capacitance, the time-dependent change of the capacitance under a DC electric field, and the acceleration of insulation resistance It is very difficult to satisfy all of the characteristics such as the life and the capacity reduction under DC bias. For example, those disclosed in JP-A-61-250905 and JP-A-2-832, respectively, have a problem that the accelerated life of the insulation resistance is short and the capacity decrease under DC bias is large.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an X7R characteristic (EIA standard) and a B characteristic (EIA standard), which are temperature characteristics of capacitance, even when the thickness of the dielectric layer is very thin. EIAJ standard), a small change in capacitance under a DC electric field with time, a long acceleration life of insulation resistance, and a small decrease in capacitance under a DC bias. An object of the present invention is to provide a manufacturing method for obtaining a dielectric layer-containing electronic component. Further, the present invention provides a method for producing a dielectric ceramic composition suitably used as a dielectric layer of a dielectric layer-containing electronic component such as a multilayer ceramic capacitor having such excellent characteristics. With the goal.

In order to achieve the above object, a method for producing a dielectric porcelain composition according to the present invention,
Expressed by a composition formula _Ba m _{TiO 2 + n,} m in the composition formula is 0.995 ≦ m ≦ 1.010, n is 0.995 ≦ n ≦ 1.010, the ratio of Ba and Ti A main component satisfying 0.995 ≦ Ba / Ti ≦ 1.010;
A second auxiliary component, which is a sintering aid containing silicon oxide as a main component,
A method for producing a dielectric ceramic composition having at least other subcomponents,
Excluding the second sub-component, mixing the main component and at least a part of other sub-components, preparing a powder before calcination,
A step of calcining the powder before calcining to prepare a calcined powder,
A step of mixing at least the second subcomponent with the calcined powder to obtain a dielectric ceramic composition in which the ratio of each subcomponent to the main component is a predetermined molar ratio.

In a first aspect of the present invention,
The second subcomponent is _{(Ba, Ca) x SiO 2} + x ( however, x = 0.8 to 1.2) having a composition represented by,
The other subcomponents,
A first auxiliary component containing at least one selected from MgO, CaO, BaO, SrO and Cr ₂ O ₃ ;
A third subcomponent including at least one kind selected from V ₂ O _5, MoO ₃ and WO _3,
A fourth subcomponent containing an oxide of R (where R is at least one selected from Y, Dy, Tb, Gd and Ho).
The calcined powder, at least the second sub-component is mixed, the ratio of each sub-component with respect to 100 mol of the main component,
First subcomponent: 0.1 to 3 mol,
Second subcomponent: 2 to 12 mol,
Third subcomponent: 0.1 to 3 mol,
It is preferable to obtain a dielectric ceramic composition in which the fourth subcomponent is 0.1 to 10.0 moles (where the number of moles of the fourth subcomponent is the ratio of R alone).

In a second aspect of the present invention,
The second subcomponent is _{(Ba, Ca) x SiO 2} + x ( however, x = 0.8 to 1.2) having a composition represented by,
The other subcomponents,
A first auxiliary component containing at least one selected from MgO, CaO, BaO, SrO and Cr ₂ O ₃ ;
A third subcomponent including at least one kind selected from V ₂ O _5, MoO ₃ and WO _3,
A fourth subcomponent containing an oxide of R (where R is at least one selected from Y, Dy, Tb, Gd and Ho);
At least a fifth subcomponent containing MnO,
The calcined powder, at least the second sub-component is mixed, the ratio of each sub-component with respect to 100 mol of the main component,
First subcomponent: 0.1 to 3 mol,
Second subcomponent: 2 to 12 mol,
Third subcomponent: 0.1 to 3 mol,
Fourth subcomponent: 0.1 to 10.0 moles (however, the number of moles of the fourth subcomponent is a ratio of R alone),
It is preferable to obtain a dielectric ceramic composition having a fifth subcomponent: 0.05 to 1.0 mol.

Note that, in the present specification, each oxide constituting the main component and each subcomponent is represented by a stoichiometric composition, but the oxidation state of each oxide may deviate from the stoichiometric composition. . However, the above ratio of each subcomponent is determined by converting the amount of metal contained in the oxide constituting each subcomponent to an oxide having the above stoichiometric composition. Further, as the raw material powder of the dielectric ceramic composition, the above-described oxides and mixtures thereof, and composite oxides can be used.Other compounds that become the above-described oxides and composite oxides by firing, for example, Carbonates, oxalates, nitrates, hydroxides, organometallic compounds and the like can be appropriately selected and used as a mixture.
Further, the ratio between Ba and Ca in the second subcomponent is arbitrary, and may contain only one of them.

  In the present invention, the average particle size of the main component is not particularly limited, but is preferably 0.1 to 0.7 μm, and more preferably 0.2 to 0.7 μm.

  In the present invention, the molar ratio of the components contained in the powder before calcination: (Ba + the metal element of the first subcomponent) / (Ti + the metal element of the fourth subcomponent) is less than 1 or (Ba + the fourth subcomponent). It is preferable that the powder before calcining is prepared and calcined so that the ratio of (metal element of the component) / (Ti + metal element of the first subcomponent) exceeds 1.

  In the present invention, when preparing the powder before calcining, it is preferable that the powder before calcining always contains the first subcomponent.

In the present invention, when the raw material of the fourth subcomponent is contained in the powder before calcination, the calcination temperature is preferably 500 ° C. or more and less than 1200 ° C., and more preferably 600 to 900 ° C. It is. When the raw material of the fourth subcomponent is not contained in the powder before calcining, the calcining temperature is preferably 600 to 1300 ° C, more preferably 900 to 1300 ° C, and particularly preferably 1000 to 1300 ° C. 1200 ° C.
Note that the calcination may be performed a plurality of times.

  The calcined powder may be mixed with at least the second subcomponent. If necessary, the main component, the first subcomponent, the third subcomponent, the fourth subcomponent, and the fifth subcomponent may be mixed. One or more of them may be further mixed, and the composition of the finally obtained dielectric ceramic composition may be within the above range.

In a third aspect of the present invention,
An internal electrode and a dielectric layer made of Ni or Ni alloy to a multilayer ceramic capacitor comprising alternately stacked dielectric layers, BaTiO _3: 100 moles, at least one of MgO or CaO: 0.1 3 mol, MnO: 0.05 to 1.0 _mol, Y ₂ O 3: _{0.1~5 moles,} V ₂ O 5: _{0.1~3 moles, Ba a Ca 1-a SiO} 3 (a in 0 to 1): 2 to 12 moles in this molar ratio in the manufacturing method of the multilayer ceramic capacitor,
BaTiO ₃ and at least one of MgO or CaO or a compound which becomes MgO or CaO by heat treatment are mixed in advance, and a material calcined at 900 ° C. to 1300 ° C. is used in an amount of 70% by weight or more based on the entire dielectric material. The present invention provides a multilayer ceramic capacitor characterized by the following.

In a fourth aspect of the present invention,
An internal electrode and a dielectric layer made of Ni or Ni alloy to a multilayer ceramic capacitor comprising alternately stacked dielectric layers, BaTiO _3: 100 moles, at least one of MgO or CaO: 0.1 3 mol, MnO: 0.05 to 1.0 _mol, Y ₂ O 3: _{0.1~5 moles,} V ₂ O 5: _{0.1~3 moles, Ba a Ca 1-a SiO} 3 (a in 0 to 1): 2 to 12 moles in this molar ratio in the manufacturing method of the multilayer ceramic capacitor,
BaTiO ₃ , MgO or CaO or at least one kind of a compound which becomes MgO or CaO by heat treatment, MnO or a compound which becomes MnO by heat treatment, Y ₂ O ₃ or a compound which becomes Y ₂ O ₃ by heat treatment, and V ₂ O ₅ or at least one selected from the group consisting of compounds that become V ₂ O ₅ by heat treatment, and a material calcined at 900 ° C. to 1300 ° C. is used in an amount of 70% by weight or more based on the entire dielectric material. A multilayer ceramic capacitor is provided.
In the third and fourth aspects of the present invention, it is preferable that the average particle diameter of BaTiO ₃ is 0.2 to 0.7 μm. In the third and fourth aspects of the present invention, the number of moles of Y ₂ O ₃ is not the number of moles of Y alone but the number of moles of Y ₂ O ₃ .

In the conventional method of manufacturing a dielectric ceramic composition, mixing the additive with Ba m _TiO 2 + _n at a time, and to prepare a mixed powder or dielectric paste, the dielectric ceramic composition. However, in the conventional method, segregation of additives (first to fifth subcomponents) and the like occurs in the dielectric ceramic composition after firing, and the composition of each crystal varies. Such segregation deteriorates the dielectric constant and insulation resistance of the dielectric.

  According to the present invention, except for the second subcomponent, the main component is mixed with at least one of the first, third, fourth and fifth subcomponents and calcined. Thereby, the composition variation between the crystal grains can be suppressed, and as a result, the segregation phase can be suppressed and the size of the segregation phase can be controlled. Therefore, according to the present invention, while satisfying both the X7R characteristic and the B characteristic, the change with time of the capacitance under a DC electric field is small, the accelerated life of insulation resistance is long, and the capacitance decrease under a DC electric field is small. A dielectric ceramic composition suitable for use in a dielectric layer-containing electronic component such as a multilayer ceramic capacitor having excellent reliability can be manufactured. This was first discovered by the present inventors.

  In addition, the dielectric ceramic composition obtained by the manufacturing method according to the present invention does not contain elements such as Pb, Bi, and Zn that evaporate and scatter, and therefore can be fired even in a reducing atmosphere. For this reason, it is possible to use a base metal such as Ni and a Ni alloy as the internal electrode, and it is possible to reduce the cost.

  In addition, the dielectric ceramic composition obtained by the production method according to the present invention satisfies the X7R characteristic and the B characteristic even when fired in a reducing atmosphere, and the deterioration of the capacitance aging characteristic and the insulation resistance due to the application of a DC electric field is suppressed. Small and excellent in reliability. For this reason, the method of the present invention can be expected to be effective also as a method of suppressing the deterioration of the rate of temperature change in a high temperature region due to the thinning of the multilayer capacitor.

  In addition, since the dielectric ceramic composition obtained by the production method according to the present invention does not contain substances such as Pb and Bi, it is possible to provide a product having a small adverse effect on the environment due to disposal and disposal after use.

  Further, in the production method according to the present invention, it is possible to realize a dielectric ceramic composition having a uniform structure with less heterogeneous phase formed by precipitation of an additive, and to reduce the dielectric constant and insulation resistance of the dielectric ceramic composition. Can be improved. In addition, the manufacturing method according to the present invention can provide a multilayer ceramic capacitor having high reliability because it is possible to prevent accidental structural defects.

  In addition, since the hetero-phase precipitation can be suppressed without changing the additive composition, it is possible to easily manufacture a dielectric layer-containing electronic component such as a multilayer ceramic capacitor having a capacity-temperature characteristic satisfying the X7R characteristic and the B characteristic. .

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a sectional view of a multilayer ceramic capacitor according to one embodiment of the present invention.

Multilayer Ceramic Capacitor Before describing the method for producing the dielectric ceramic composition according to the present invention, first, a multilayer ceramic capacitor will be described.
As shown in FIG. 1, a multilayer ceramic capacitor 1 according to one embodiment of the present invention has a capacitor element body 10 having a configuration in which dielectric layers 2 and internal electrode layers 3 are alternately stacked. At both ends of the capacitor element body 10, a pair of external electrodes 4 are formed, each of which is electrically connected to the internal electrode layers 3 alternately arranged inside the element body 10. The shape of the capacitor element body 10 is not particularly limited, but is usually a rectangular parallelepiped. The size is not particularly limited, and may be an appropriate size depending on the application. Usually, the size is (0.6 to 5.6 mm, preferably 0.6 to 3.2 mm) × (0.3 About 5.0 mm, preferably 0.3 to 1.6 mm) × (0.3 to 1.9 mm, preferably 0.3 to 1.6 mm).

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

Dielectric layer 2
The dielectric layer 2 contains the dielectric ceramic composition obtained by the manufacturing method of the present invention. Dielectric porcelain composition obtained by the production method of the present invention,
Expressed by a composition formula _Ba m _{TiO 2 + n,} m in the composition formula is 0.995 ≦ m ≦ 1.010, n is 0.995 ≦ n ≦ 1.010, the ratio of Ba and Ti A main component satisfying 0.995 ≦ Ba / Ti ≦ 1.010;
A first auxiliary component containing at least one selected from MgO, CaO, BaO, SrO and Cr ₂ O ₃ ;
A second subcomponent represented by (Ba, Ca) _x SiO _{2 + x} (where x = 0.8 to 1.2);
A third subcomponent including at least one kind selected from V ₂ O _5, MoO ₃ and WO _3,
And a fourth subcomponent containing an oxide of R (where R is at least one selected from Y, Dy, Tb, Gd and Ho).

The ratio of each sub-component to the main component is, with respect to 100 moles of the main component,
First subcomponent: 0.1 to 3 mol,
Second subcomponent: 2 to 12 mol,
Third subcomponent: 0.1 to 3 mol,
Fourth subcomponent: 0.1 to 10.0 mol.
The above ratio of the fourth subcomponent is not the molar ratio of the R oxide, but the molar ratio of R alone. That is, for example, when an oxide of Y is used as the fourth subcomponent, the fact that the ratio of the fourth subcomponent is 1 mol means that the ratio of Y ₂ O ₃ is not 1 mol, but the ratio of Y is 1 mol. It means that

  In the present specification, each oxide constituting the main component and each subcomponent is represented by a stoichiometric composition, but the oxidation state of each oxide may deviate from the stoichiometric composition. However, the above ratio of each subcomponent is determined by converting the amount of metal contained in the oxide constituting each subcomponent to an oxide having the above stoichiometric composition. Further, as the raw material powder of the dielectric ceramic composition, the above-described oxides and mixtures thereof, and composite oxides can be used.Other compounds that become the above-described oxides and composite oxides by firing, for example, Carbonates, oxalates, nitrates, hydroxides, organometallic compounds and the like can be appropriately selected and used as a mixture.

The reasons for limiting the content of each of the above subcomponents are as follows.
When the first auxiliary component content of (MgO, CaO, BaO, SrO and _Cr 2 _{O 3)} is too small, effect of suppressing the capacity reduction under DC bias tends to become insufficient. On the other hand, if the content is too large, the dielectric constant tends to be significantly reduced, and the accelerated life of insulation resistance tends to be short. Note that the constituent ratio of each oxide in the first subcomponent is arbitrary.

Second subcomponent BaO and CaO in _{[(Ba, Ca) x SiO} 2 + x] in the are also included in the first subcomponent, a composite oxide _{(Ba, Ca) x SiO 2} + x is the main component has a low melting point In the present invention, BaO and / or CaO are also added as the above-mentioned composite oxide because of its good reactivity with respect to. If the content of the second subcomponent is too small, the sinterability tends to be poor, the accelerated life of the insulation resistance is short, and the temperature characteristics of the capacitance tend to be difficult to satisfy the X7R characteristics standard. On the other hand, if the content is too large, the dielectric constant is low, the capacity is reduced, and the accelerated life of the insulation resistance is shortened.

_{X in} (Ba, Ca) xSiO2 _{+ x} is preferably 0.8 to 1.2, and more preferably 0.9 to 1.1. When x is too small, i.e. when SiO ₂ is too much, it causes the dielectric characteristic to deteriorate reacts with _Ba m _{TiO 2 + n} in the main component. On the other hand, if x is too large, the melting point becomes high and the sinterability deteriorates, which is not preferable. In the second subcomponent, the ratio between Ba and Ca is arbitrary, and the second subcomponent may contain only one of them.

If the content of the third subcomponent (V ₂ O ₅ , MoO ₃ and WO ₃ ) is too small, the breakdown voltage tends to decrease, and the temperature characteristics of the capacitance tend to be less likely to satisfy the X7R characteristics. On the other hand, if the content is too large, the initial insulation resistance tends to decrease. Note that the constituent ratio of each oxide in the third subcomponent is arbitrary.

  If the content of the fourth subcomponent (R oxide) is too small, the accelerated life of insulation resistance tends to be short. On the other hand, if the content is too large, the sinterability tends to deteriorate. Among these, from the viewpoint of satisfying the X7R characteristic, among the fourth subcomponents, a Y oxide, a Dy oxide, and a Ho oxide are preferable. In particular, Y oxide is preferable because it has a high effect of improving characteristics and is inexpensive.

  If necessary, the dielectric ceramic composition of the present invention may contain MnO as a fifth subcomponent. The fifth subcomponent has an effect of promoting sintering and an effect of reducing dielectric loss (tan δ). In order to sufficiently obtain such effects, it is preferable that the ratio of the fifth subcomponent to 100 mol of the main component is 0.05 mol or more. However, if the content of the fifth subcomponent is too large, the capacity-temperature characteristics are adversely affected, so the content is preferably 1.0 mol or less.

The dielectric ceramic composition of the present invention may contain Al ₂ O _{3 in} addition to the above oxides. Al ₂ O ₃ does not significantly affect the capacity-temperature characteristics, and exhibits an effect of improving sinterability, insulation resistance, and accelerated life (IR life) of insulation resistance. However, if the content of Al ₂ O ₃ is too large, the sinterability deteriorates and the IR decreases, so that Al ₂ O ₃ is preferably 1 mol or less, more preferably 100 mol or less per 100 mol of the main component. Not more than 1 mol of the whole dielectric ceramic composition.

When at least one of Sr, Zr, and Sn replaces Ba or Ti in the main component of the perovskite structure, the Curie temperature shifts to a lower temperature side, so that the capacitance-temperature characteristic at 125 ° C. or more is obtained. Gets worse. Therefore, _Ba m _{TiO 2 + n} [for example (Ba, Sr) TiO _3] containing these elements is preferably not used as the main component. However, there is no particular problem as long as it is contained as an impurity (about 0.1 mol% or less of the whole dielectric ceramic composition).

  The average crystal grain size of the dielectric ceramic composition of the present invention is not particularly limited, and is, for example, in the range of 0.1 to 3.0 μm, and preferably 0.1 to 0.7 μm, depending on the thickness of the dielectric layer. May be determined as appropriate. The capacitance-temperature characteristics tend to be worse as the dielectric layer is thinner, and worse as the average crystal grain size is smaller. Therefore, the dielectric ceramic composition of the present invention is particularly effective when it is necessary to reduce the average crystal grain size, specifically, when the average crystal grain size is 0.1 to 0.5 μm. is there. In addition, if the average crystal grain size is reduced, the IR life is prolonged, and the change with time of the capacity under a DC electric field is reduced, and from this point, the average crystal grain size is preferably small as described above. .

  The dielectric layer 2 of the present invention is composed of grains, grain boundaries, and grain boundary phases. Further, it may be composed of a composition having a so-called core-shell structure.

  Various conditions such as the thickness and the number of dielectric layers composed of the dielectric ceramic composition of the present invention may be appropriately determined according to the purpose and application. For example, the thickness of the dielectric layer is usually 50 μm or less, particularly 10 μm or less per layer. The lower limit of the thickness is usually about 1 μm. The dielectric ceramic composition of the present invention is effective for improving the capacitance-temperature characteristics of a multilayer ceramic capacitor having such a thin dielectric layer. The number of stacked dielectric layers is usually 2 to 400, preferably about 10 to 400.

  The multilayer ceramic capacitor using the dielectric ceramic composition of the present invention is particularly suitable for use as an electronic component for equipment used in an environment of -55 ° C to + 125 ° C. In such a temperature range, the temperature characteristic of the capacitance satisfies the X7R characteristic of the EIA standard (−55 to 125 ° C., ΔC = ± 15%), and at the same time, the B characteristic of the EIAJ standard [−25 to 85 ° C. Within ± 10% (reference temperature 20 ° C.)].

  In the multilayer ceramic capacitor, an AC electric field of usually 0.02 V / μm or more, particularly 0.2 V / μm or more, more preferably 0.5 V / μm or more, and generally about 5 V / μm or less is applied to the dielectric layer. A superimposed DC electric field of 5 V / μm or less is applied. Even when such an electric field is applied, the temperature characteristics of the capacitance are extremely stable.

Internal electrode layer 3
The conductive material contained in the internal electrode layer 3 is not particularly limited, but a base metal can be used because the constituent material of the dielectric layer 2 has reduction resistance. As the base metal used as the conductive material, Ni or a Ni alloy is preferable. As the Ni alloy, an alloy of one or more elements selected from Mn, Cr, Co and Al with Ni is preferable, and the Ni content in the alloy is preferably 95% by weight or more.
In addition, various trace components such as P may be contained in Ni or Ni alloy at about 0.1% by weight or less.
The thickness of the internal electrode layer may be appropriately determined according to the application and the like, and is usually about 0.5 to 5 μm, preferably about 0.5 to 2.5 μm, and more preferably about 1 to 2 μm.

External electrode 4
The conductive material contained in the external electrode 4 is not particularly limited, but in the present invention, inexpensive Ni, Cu, or an alloy thereof can be used.
The thickness of the external electrode may be appropriately determined according to the application and the like, but is usually preferably about 10 to 100 μm.

Manufacturing method of multilayer ceramic capacitor The multilayer ceramic capacitor manufactured using the manufacturing method of the dielectric ceramic composition according to the present invention is a green chip manufactured by a normal printing method or a sheet method using a paste. After firing, the external electrodes are printed or transferred and fired. Hereinafter, the manufacturing method will be specifically described.

First, the dielectric ceramic composition powder contained in the dielectric layer paste is prepared. As the BaTiO ₃ powder in the dielectric ceramic composition powder, usually, not only powder obtained by mixing, calcining, and pulverizing the raw materials, which is obtained by a so-called solid-phase method, but also an oxalate method and a hydrothermal synthesis method. Powder obtained by a so-called liquid phase method may be used.

In the present invention, calcining is performed before obtaining the dielectric ceramic composition powder having the above-described composition. That is, the second by-component _(Ba, Ca) except for x _{SiO 2 + x,} main component _(Ba m _{TiO 2 + n),} a first subcomponent (e.g. MgO or CaO or a compound comprising a MgO or CaO by heat treatment), A third subcomponent (for example, V ₂ O ₅ or a compound that becomes V ₂ O ₅ by heat treatment), a fourth subcomponent (for example, Y ₂ O ₃ or a compound that becomes Y ₂ O ₃ by heat treatment) and a fifth subcomponent (for example, At least one of MnO or a compound which becomes MnO by heat treatment) is mixed and dried to prepare a powder before calcining.

Compounds that become MgO or CaO by heat treatment include MgCO ₃ , MgCl ₂ , MgSO ₄ , Mg (NO ₃ ) ₂ , Mg (OH) ₂ , (MgCO ₃ ) ₄ Mg (OH) ₂ , CaCO ₃ , and CaCl ₃ . ₂ , CaSO ₄ , Ca (NO ₃ ) ₂ , Mg alkoxide, Ca alkoxide and the like, or a hydrate thereof. Examples of the compound that becomes MnO by the heat treatment include MnCO ₃ , MnCl ₂ , MnSO ₄ , Mn (NO ₃ ) _2, and a hydrate thereof. Examples of the compound which becomes Y ₂ O ₃ by the heat treatment include YCl ₃ , Y ₂ (SO ₄ ) ₃ , Y (NO ₃ ) ₃ , Y (CH ₃ COO) ₃ , Y alkoxide, and the like, or a hydrate thereof. Is exemplified. Furthermore, examples of the compound that becomes V ₂ O ₅ by the heat treatment include VCl ₅ , V ₂ (SO ₄ ) ₅ , V (NO ₃ ) _{5, and the} like, or a hydrate thereof.

The powder before calcination is then calcined. The calcination conditions are not particularly limited, but are preferably performed under the following conditions.
Heating rate: 50 to 400 ° C / hour, especially 100 to 300 ° C / hour,
Holding temperature: 500 ° C to 1300 ° C, preferably 500 ° C to less than 1200 ° C,
Temperature holding time: 0.5 hours to 6 hours, especially 1 to 3 hours,
Atmosphere: in air and in nitrogen.

The calcined calcined powder is roughly pulverized by an alumina roll or the like, and then at least (Ba, Ca) _x SiO _{2 + x} as a _second subcomponent is added, and if necessary, the remaining additives are added. To obtain a mixed powder having the final composition described above. Thereafter, the mixed powder is mixed by a ball mill or the like, if necessary, and dried to obtain a dielectric ceramic composition powder having the composition of the present invention.

  The molar ratio of each component in the calcined calcined powder is not particularly limited, but preferably satisfies the following relational expression. That is, (Ba + metal element of first subcomponent) / (Ti + metal element of fourth subcomponent) is less than 1 or (Ba + metal element of fourth subcomponent) / (Ti + metal element of first subcomponent). Preferably, it exceeds 1. In such a range, the accelerated life of the insulation resistance is particularly improved.

  Preferably, the calcined powder always contains the first subcomponent. When the total weight of the first subcomponent in the final composition powder is 100% by weight, the calcined powder preferably contains 30% by weight, more preferably 50% by weight of the first subcomponent. It is preferred that

  The calcined powder is used in an amount of preferably 70% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, with the dielectric ceramic composition powder finally obtained being 100% by weight. It is mixed with additional ingredients. If the proportion of the calcined powder is too small, the accelerated life of the insulation resistance is short, and the capacity tends to decrease significantly under a DC bias.

  Next, the finally obtained dielectric ceramic composition powder 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 ceramic composition powder and an organic vehicle, or may be an aqueous paint.

  The particle size of the dielectric porcelain composition powder before coating is usually 0.1 to 3 μm, preferably about 0.1 to 0.7 μm, in average particle size.

  The organic vehicle is obtained by dissolving a binder (binder) in an organic solvent. The binder used for the organic vehicle is not particularly limited, and may be appropriately selected from various ordinary binders such as ethyl cellulose and polyvinyl butyral. In addition, the organic solvent to be used is not particularly limited, and may be appropriately selected from various organic solvents such as terpineol, butyl carbitol, methyl ethyl ketone, acetone, and toluene according to a method to be used such as a printing method and a sheet method.

  Further, when the dielectric layer paste is an aqueous paint, an aqueous vehicle in which a water-soluble binder, dispersant, or the like is dissolved in water may be kneaded with a dielectric material. The water-soluble binder used for the aqueous vehicle is not particularly limited, and for example, polyvinyl alcohol, cellulose, a water-soluble acrylic resin, or the like may be used.

The internal electrode layer paste is made of a conductive material made of the above-mentioned various dielectric metals or alloys, or various oxides, organometallic compounds, resinates, etc. (conductive material etc.) which become the above-mentioned conductive material after firing, and the above-mentioned organic vehicle. And kneaded. The shape of the conductive material in the paste is not particularly limited, and examples thereof include a sphere and a scale, and a mixture of these shapes may be used.
The external electrode paste may be prepared in the same manner as the internal electrode layer paste described above.

  The content of the organic vehicle in each of the above-mentioned pastes is not particularly limited, and may be a usual content, for example, about 1 to 5% by weight of a binder and about 10 to 50% by weight of a solvent. Each paste may contain auxiliary additives selected from various dispersants, plasticizers, dielectrics, insulators, and the like, if necessary. The total content of these auxiliary additives is preferably 10% by weight or less.

  As the plasticizer, for example, polyethylene glycol, phthalic acid ester (eg, dioctyl phthalate, dibutyl phthalate) and the like are used. Further, as the dispersant, for example, oleic acid, rosin, glycerin, octadecylamine, ethyl oleate, mensesden oil and the like are used.

  In particular, when preparing the dielectric layer paste (slurry), the content of the dielectric porcelain composition powder in the paste is about 50 to 80% by weight based on the whole paste, and the binder is 2 to 50% by weight. It is preferable that 5 wt%, the plasticizer is 0.1 to 5 wt%, the dispersant is 0.1 to 5 wt%, and the solvent is about 20 to 50 wt%.

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

  In the case of using a sheet method, a green sheet is formed using a dielectric layer paste, an internal electrode layer paste is printed thereon, and these are laminated to form a green chip.

Before firing, the green chip is subjected to a binder removal treatment. The binder removal treatment may be performed under ordinary conditions. When a base metal such as Ni or a Ni alloy is used as the conductive material of the internal electrode layer, it is particularly preferable to perform the treatment under the following conditions.
Heating rate: 5 to 300 ° C / hour, especially 10 to 100 ° C / hour,
Holding temperature: 180-400 ° C, especially 200-300 ° C,
Temperature holding time: 0.5 to 24 hours, especially 5 to 20 hours,
Atmosphere: in the air.

The atmosphere at the time of firing the green chip may be appropriately determined according to the type of the conductive material in the internal electrode layer paste, but when a base metal such as Ni or a Ni alloy is used as the conductive material, the oxygen content in the firing atmosphere may be reduced. The pressure is preferably from 10 ^-7 to 10 ^-13 atm, more preferably from 10 ^-10 to 10 ^-12 atm. If the oxygen partial pressure is less than the above range, the conductive material of the internal electrode layer may abnormally sinter and be interrupted. If the oxygen partial pressure exceeds the above range, the internal electrode layer tends to be oxidized.

  The holding temperature during firing is preferably 1100 to 1400 ° C, more preferably 1150 to 1400 ° C, and still more preferably 1200 to 1300 ° C. If the holding temperature is less than the above range, the densification becomes insufficient, and if the holding temperature exceeds the above range, the electrode is interrupted due to abnormal sintering of the internal electrode layer, the deterioration of the capacitance temperature characteristic due to the diffusion of the internal electrode layer constituent material, the dielectric Reduction of the body porcelain composition is likely to occur.

Preferably, various conditions during firing other than the above conditions are selected from the following ranges.
Heating rate: 100 to 900 ° C / hour, especially 200 to 900 ° C / hour,
Temperature holding time: 0.5 to 8 hours, especially 1 to 3 hours,
Cooling rate: 50-500 ° C / hour, especially 200-300 ° C / hour.
Note that the firing atmosphere is preferably a reducing atmosphere. As the atmosphere gas, for example, a mixed gas of N ₂ and H ₂ is preferably used after being humidified.

  When firing in a reducing atmosphere, the capacitor element body is preferably annealed. Annealing is a process for reoxidizing the dielectric layer, which can significantly increase the IR lifetime, thereby improving reliability.

The oxygen partial pressure in the annealing atmosphere is preferably set to 10 ⁻⁴ to 10 ⁻⁷ atm. If the oxygen partial pressure is less than the above range, it is difficult to reoxidize the dielectric layer, and if it exceeds the above range, the internal electrode layer tends to be oxidized.

  The holding temperature at the time of annealing is preferably 1200 ° C. or less, particularly preferably 500 to 1200 ° C. If the holding temperature is lower than the above range, the oxidation of the dielectric layer becomes insufficient, so that the IR is low and the IR life tends to be short. On the other hand, when the holding temperature exceeds the above-mentioned range, not only the internal electrode layer is oxidized and the capacity is reduced, but also the internal electrode layer reacts with the dielectric substrate, so that the capacity-temperature characteristic is deteriorated, the IR is lowered, and the IR is lowered. The life is likely to be shortened. Note that the annealing may include only the temperature increasing process and the temperature decreasing process. That is, the temperature holding time may be set to zero. In this case, the holding temperature is synonymous with the maximum temperature.

Various conditions during annealing other than the above conditions are preferably selected from the following ranges.
Temperature holding time: 0.5 to 12 hours, especially 6 to 10 hours,
Cooling rate: 50 to 600 ° C./hour, particularly 100 to 300 ° C./hour It is preferable to use a humidified N ₂ gas or the like as the atmosphere gas.

In the above-described binder removal processing, firing, and annealing, for example, a wetter or the like may be used to humidify the N ₂ gas, the mixed gas, or the like. In this case, the water temperature is preferably about 5 to 75C.

The binder removal treatment, firing and annealing may be performed continuously or independently. When these are continuously performed, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of firing, firing is performed, and then cooling is performed, and the temperature reaches the holding temperature of annealing. It is preferable to change the atmosphere sometimes and perform annealing. On the other hand, in the case where these steps are performed independently, upon firing, the temperature should be increased in a N ₂ gas or humidified N ₂ gas atmosphere to the holding temperature at the time of the binder removal treatment, and then the atmosphere should be changed to further increase the temperature. After cooling to the holding temperature at the time of annealing, it is preferable to change the atmosphere to N ₂ gas or a humidified N ₂ gas atmosphere again and continue cooling. Further, at the time of annealing, after raising the temperature to the holding temperature under N ₂ gas atmosphere, then change the atmosphere or a wet N ₂ gas atmosphere the entire process of annealing.

The end surface of the capacitor element body obtained as described above is polished by, for example, barrel polishing or sandblasting, and the external electrode paste is printed or transferred and baked to form the external electrode 4. The firing conditions for the external electrode paste are preferably, for example, about 10 minutes to 1 hour at 600 to 800 ° C. in a humidified mixed gas of N ₂ and H ₂ . Then, if necessary, a coating layer is formed on the surface of the external electrode 4 by plating or the like.

  The multilayer ceramic capacitor of the present invention manufactured as described above has a capacitance temperature change rate satisfying the EIA standard X7R characteristic and the EIAJ standard according to the ultra-thin layer having a dielectric layer thickness of 4 μm or less. Satisfies the B characteristic. Further, the multilayer ceramic capacitor of the present invention has a small change with time in capacitance under a DC electric field, a long accelerated life of insulation resistance, and a small decrease in capacitance under DC bias.

  The multilayer ceramic capacitor of the present invention manufactured in this manner is mounted on a printed circuit board or the like by soldering or the like, and is used in various electronic devices and the like.

Note that the present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the present invention.
For example, the dielectric porcelain composition obtained by the production method according to the present invention is not limited to being used only for a multilayer ceramic capacitor, but may be used for other electronic components on which a dielectric layer is formed.

  Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

Example 1
Samples A1 to A10 of the multilayer ceramic capacitor were manufactured by the following procedure.
First, the following pastes were prepared.

Dielectric layer paste First, a main component material and a subcomponent material were prepared. As the main component material, BaTiO ₃ having a particle size of 0.2 to 0.7 μm obtained by a hydrothermal synthesis method was used. Carbonates were used as raw materials for MgO and MnO, and oxides were used as raw materials for other subcomponents. As a magnesium carbonate as a raw material of MgO, (MgCO ₃ ) ₄ Mg (OH) ₂ .5H ₂ O was used. MnCO ₃ was used as a carbonate as a raw material of MnO.

Further, (Ba _0.6 Ca _0.4 ) SiO ₃ was used as a raw material of the second subcomponent. In addition, (Ba _0.6 Ca _0.4 ) SiO ₃ was obtained by wet mixing BaCO ₃ , CaCO ₃ and SiO ₂ with a ball mill for 16 hours, drying, firing at 1150 ° C. in air, and further mixing with a ball mill. Manufactured by wet grinding for hours.

First, BaTiO _{3 as} a main component and magnesium carbonate as a raw material of a first subcomponent were mixed and dried to prepare a powder before calcining. As shown in Table 1, the powder before calcining contained 2.1 mol of magnesium carbonate in terms of MgO with respect to 100 mol of BaTiO ₃ . Further, the molar ratio of the specific component in the powder before calcining: (Ba + metal element Mg in the first subcomponent) / (Ti + metal element Y in the fourth subcomponent) was examined. Thus, it was 1.021. When the molar ratio: (Ba + the metal element Y in the fourth subcomponent) / (Ti + the metal element Mg in the first subcomponent) was examined, it was 0.9794 as shown in Table 1.

Next, the powder before calcining was calcined. The calcination conditions were as follows.
Heating rate: 300 ° C / hour,
Holding temperature (T1 in Table 1): 500 to 1350 ° C.
Temperature holding time: 3 hours,
Atmosphere: in the air.

The material obtained by this calcining was pulverized with a raikai machine for 1 hour to obtain a calcined powder, and then, as shown in Table 2, 3.0 mol of ( Ba _0.6 Ca _0.4 ) SiO ₃ , 0.375 mol of MnCO ₃ , 0.1 mol of V ₂ O ₅ , and 2.1 mol of Y ₂ O ₃ (the number of mols of Y is 4.2 mol. And the same hereinafter) was added thereto, and the mixture was wet-mixed for 16 hours using a zirconia ball mill and then dried to obtain a dielectric ceramic composition powder having a final composition.

  100 parts by weight of the dielectric ceramic composition powder thus obtained, 4.8 parts by weight of acrylic resin, 40 parts by weight of methylene chloride, 20 parts by weight of ethyl acetate, 6 parts by weight of mineral spirit, and acetone 4 parts by weight were mixed with a ball mill for 16 hours to form a paste.

44.6 parts by weight of Ni particles having an average particle diameter of 0.4 μm for the internal electrode layer paste , 52.0 parts by weight of terbineol, 3.0 parts by weight of ethylcellulose, and 0.4 parts by weight of benzotriazole: The mixture was kneaded with three rolls to form a paste.

100 parts by weight of Cu particles having an average particle size of 2 μm for the external electrode paste, 35 parts by weight of an organic vehicle (8 parts by weight of ethyl cellulose resin dissolved in 92 parts by weight of butyl carbitol) and 7 parts by weight of butyl carbitol are kneaded. , Into a paste.

Production of Green Chip A green sheet having a thickness of 5 μm was formed on a PET film using the above-mentioned dielectric layer paste. After printing the internal electrode paste on the surface of the green sheet, the sheet was peeled off from the PET film. Next, four layers of the green sheet after printing the paste for the internal electrode layer are sandwiched between a plurality of protective green sheets (ones on which the paste for the internal electrode layer is not printed) and laminated, and then pressed at 120 ° C. and 15 Pa. To obtain a green chip.

Firing First, the green chip is cut into a predetermined size, binder removal processing, firing and annealing are performed under the following conditions, and then external electrodes are formed. Samples A1 to A10 of the multilayer ceramic capacitor having the configuration shown in FIG. Got.

Binder removal processing conditions Temperature rise rate: 15 ° C / hour,
Holding temperature: 280 ° C,
Temperature holding time: 8 hours,
Atmosphere: in the air.

Firing conditions Temperature rise rate: 200 ° C / hour,
Holding temperature: 1270 ° C,
Temperature holding time: 2 hours,
Cooling rate: 300 ° C / hour,
Atmosphere gas: humidified N ₂ + H ₂ mixed gas,
Oxygen partial pressure: ^10-12 atm.

Annealing condition holding temperature: 1000 ° C.
Temperature holding time: 3 hours,
Cooling rate: 300 ° C / hour,
Atmosphere gas: Humidified N ₂ gas,
Oxygen partial pressure: ^10-6 atm.
Note that a wetter with a water temperature of 35 ° C. was used for humidifying the respective atmosphere gases during the binder removal processing, firing, and annealing.

External electrode The external electrode was formed by polishing the end face of the fired body by sandblasting, transferring the paste for external electrode to the end face, and firing the paste at 800 ° C. for 10 minutes in a humidified N ₂ + H ₂ atmosphere. .

  The size of each sample thus obtained was 3.2 mm × 1.6 mm × 1.4 mm, the number of dielectric layers sandwiched between the internal electrode layers was 4, the thickness was 3 μm, The thickness of the internal electrode layer was 1.3 μm.

  In addition to the capacitor samples, disk-shaped samples were also made. This disk-shaped sample has the same composition as the dielectric layer of the capacitor sample and the same sintering conditions, and is obtained by coating an In-Ga electrode having a diameter of 5 mm on both surfaces of the sample.

The following characteristics were evaluated for each sample.
Relative permittivity (εr)
The capacity of the disc-shaped sample was measured at 25 ° C. using an LCR meter under the conditions of 1 kHz and 1 Vrms. Then, the relative dielectric constant was calculated from the capacitance, the electrode dimensions, and the thickness of the sample. Table 2 shows the results. The higher the relative permittivity, the better.

Breakdown voltage (VB)
The breakdown voltage was determined by applying a DC voltage to a sample of the multilayer chip capacitor at a step-up speed of 100 V / sec and measuring a voltage when a leakage current of 100 mA was observed. Table 2 shows the results. The higher the breakdown voltage, the better.

IR life under DC electric field (High temperature accelerated life: HALT in the table)
An acceleration test was performed on the sample of the multilayer chip capacitor at 180 ° C. under an electric field of 10 V / μm, and the time until the insulation resistance (IR) became 2 × 10 ⁵ Ω or less was defined as the life time. Table 2 shows the results. The longer the life, the better the durability of the capacitor.

Temperature characteristics of capacitance (TCC in the table)
The capacitance of the sample of the multilayer chip capacitor was measured in a temperature range of −55 to + 125 ° C., and it was examined whether or not the X7R characteristic was satisfied. Note that an LCR meter was used for the measurement, and the measurement voltage was 1 V. It was examined whether or not the capacity change rate was within ± 15% (reference temperature 25 ° C.). When satisfied, it was evaluated as ○, and when it was not satisfied, as ×.

  Regarding the B characteristic, the capacitance was measured at a measurement voltage of 1 V at −25 to 85 ° C. using an LCR meter, and it was examined whether or not the rate of change of the capacitance was within ± 10% (reference temperature: 20 ° C.). When satisfied, it was evaluated as ○, and when not satisfied, as ×.

Time-dependent change in capacitance under DC electric field A DC electric field (applied voltage to the sample: 7.5 V) of 2.5 V per 1 μm of the dielectric layer was applied to the sample of the multilayer chip capacitor at 40 ° C. for 100 hours. Then, after being left at room temperature for 24 hours in a no-load state, the capacity is measured, and a change amount ΔC from the capacity C ₀ (initial capacity) before application of the DC electric field is obtained, and a change rate ΔC / C ₀ is calculated. did. The capacity was measured under the above conditions.

Capacitance was measured at room temperature while applying a DC electric field of 0 to 13 V / μm using a capacitance-reducing LCR meter under a DC bias, and an electric field at which the capacitance under the DC electric field became −50% was determined. It is preferably at least 6.3 V / μm or more, preferably 6.5 V / μm or more.

Comparative Example 1
As shown in Tables 1 and 2, 2.1 mol of (MgCO ₃ ) ₄ Mg (OH) ₂ .5H ₂ O in terms of MgO with respect to 100 mol of BaTiO _{3 as} a main component without being calcined. A mixture containing 0.375 mol of MnCO ₃ , 3.0 mol of (Ba _0.6 Ca _0.4 ) SiO ₃ , 0.1 mol of V ₂ O ₅ , and 2.1 mol of Y ₂ O ₃ A cylindrical sample and a capacitor sample A11 were prepared in the same manner as in the sample of Example 1 except that firing was performed using the powder, and the same test as in Example 1 was performed. Table 2 shows the results.

Example 2
As shown in Table 1, columnar samples and capacitor samples B1 and B2 were prepared in the same manner as in Example 1 except that CaO was used as the first subcomponent and the calcination temperature was 1000 ° C. and 1100 ° C. Prepared and performed the same test as in Example 1. Table 2 shows the results.

  In addition, when the molar ratio of the specific component in the powder before calcining: (Ba + Ca) / (Ti + Y) was examined, it was 1.021 as shown in Table 1. Further, when the molar ratio: (Ba + Y) / (Ti + Ca) was examined, it was 0.9794 as shown in Table 1.

Example 3
As shown in Table 1, as the fourth component, 2.1 mol of Y ₂ O ₃ , or 2.1 mol of Y ₂ O ₃ and 0.375 mol of MnCO ₃ were contained in the powder before calcining. And a columnar sample and capacitor samples C1 to C10 were prepared in the same manner as in Example 1 except that the calcination temperature was 700 to 1100 ° C., and the same test as in Example 1 was performed. . Table 2 shows the results.

  In addition, when the molar ratio of the specific component in the powder before calcination: (Ba + Mg) / (Ti + Y) was examined, it was 0.9798 as shown in Table 1. When the molar ratio: (Ba + Y) / (Ti + Mg) was examined, it was 1.0206 as shown in Table 1.

Example 4
As shown in Table 1, 0.1 mol of V ₂ O ₅ as the third component, 2.1 mol of Y ₂ O ₃ as the fourth component, and 5 A columnar sample and capacitor samples D1 to D9 were prepared in the same manner as in Example 1 except that 0.375 mol of MnCO ₃ was further added as a component and the calcination temperature was set to 500 to 1300 ° C. The same test as in Example 1 was performed. Table 2 shows the results.

  In addition, when the molar ratio of the specific component in the powder before calcination: (Ba + Mg) / (Ti + Y) was examined, it was 0.9798 as shown in Table 1. When the molar ratio: (Ba + Y) / (Ti + Mg) was examined, it was 1.0206 as shown in Table 1.

Example 5
As shown in Table 1, instead of Y ₂ O ₃ as the fourth component, Dy ₂ O ₃ or Ho ₂ O ₃ was contained in the powder before calcination at a content of 2.1 mol, and A cylindrical sample and capacitor samples E1 and E2 were prepared in the same manner as in Example 4 except that the baking temperature was set to 800 ° C., and the same test as in Example 1 was performed. Table 2 shows the results.

  In addition, when the molar ratio of the specific component in the powder before calcination: (Ba + Mg) / (Ti + Dy or Ho) was examined, it was 0.9798 as shown in Table 1. Further, when the molar ratio: (Ba + Dy or Ho) / (Ti + Mg) was examined, it was 1.0206 as shown in Table 1.

Example 6
As shown in Table 1, instead of Y ₂ O ₃ as the fourth component, Gd ₂ O ₃ was calcined at a content of 1.5 mol (the number of mols of Gd was 3.0 mol, and the same hereinafter). A columnar sample and a capacitor sample E3 were prepared in the same manner as in Example 4 except that the powder was contained in the pre-powder and the calcination temperature was 800 ° C., and the same test as in Example 4 was performed. . Table 2 shows the results.

  In addition, when the molar ratio of the specific component in the powder before calcination: (Ba + Mg) / (Ti + Gd) was examined, it was 0.9951 as shown in Table 1. Further, when the molar ratio: (Ba + Gd) / (Ti + Mg) was examined, it was 1.0049 as shown in Table 1.

Comparative Example 2
As shown in Tables 1 and 2, 2.5 mol of (MgCO ₃ ) ₄ Mg (OH) ₂ .5H ₂ O in terms of MgO was calculated with respect to 100 mol of BaTiO _{3 as} a main component without calcining. A mixture containing 0.375 mol of MnCO ₃ , 3.0 mol of (Ba _0.6 Ca _0.4 ) SiO ₃ , 0.1 mol of V ₂ O ₅ , and 1.5 mol of Gd ₂ O ₃ A columnar sample and a capacitor sample E4 were prepared in the same manner as in the sample of Example 6 except that firing was performed using the powder, and the same test as in Example 6 was performed. Table 2 shows the results.

Example 7
As shown in Table 1, in place of Y ₂ O ₃ as the fourth component, Tb ₄ O ₇ was calcined at a content of 0.7 mol (the number of mols of Tb is 2.8 mol, the same applies hereinafter). A columnar sample and a capacitor sample E5 were prepared in the same manner as in Example 4 except that the powder was contained in the pre-powder and the calcination temperature was 800 ° C., and the same test as in Example 4 was performed. . Table 2 shows the results.

  In addition, when the molar ratio of the specific component in the powder before calcination: (Ba + Mg) / (Ti + Tb) was examined, it was 0.9971 as shown in Table 1. Further, when the molar ratio: (Ba + Tb) / (Ti + Mg) was examined, it was 1.0029 as shown in Table 1.

Comparative Example 3
As shown in Tables 1 and 2, 2.5 mol of (MgCO ₃ ) ₄ Mg (OH) ₂ .5H ₂ O in terms of MgO was calculated with respect to 100 mol of BaTiO _{3 as} a main component without calcining. A mixture containing 0.375 mol of MnCO ₃ , 3.0 mol of (Ba _0.6 Ca _0.4 ) SiO ₃ , 0.1 mol of V ₂ O ₅ , and 0.7 mol of Tb ₄ O ₇ A cylindrical sample and a capacitor sample E6 were prepared in the same manner as in the sample of Example 7 except that the powder was fired, and the same test as in Example 7 was performed. Table 2 shows the results.

Example 8
In the powder before calcining, 60 to 80 mol of BaTiO ₃ was added with magnesium carbonate in the amount shown in Table 3 in terms of MgO, and in the calcined powder, as shown in Table 4, In the same manner as in Example 1, except that a main component and an auxiliary component which are not calcined were additionally added so that the weight% of the calcined component was 60 to 80% by weight, F1 to F3 were prepared, and the same test as in Example 1 was performed. Table 2 shows the results.

  In addition, when the molar ratio of the specific component in the powder before calcination: (Ba + Mg) / (Ti + Y) was examined, it was 1.021 as shown in Table 1. Further, when the molar ratio: (Ba + Y) / (Ti + Mg) was examined, it was 0.9794 as shown in Table 1.

As shown in Evaluation Tables 1 to 4, in the examples of the present invention, it was confirmed that the X7R characteristics and the B characteristics can all be satisfied. Further, the sample number A11 of Comparative Example 1 was compared with the sample numbers A1 to A10, B1, B2, C1 to C10, D1 to D9, E1, E2, and F1 to F3 of Example 1. In the example, it was confirmed that the IR accelerated life was longer, the change in the capacitance under a DC electric field with the passage of time was small, and the capacitance half-reduced electric field under a DC electric field was higher.

  Further, for example, by comparing sample number A11 as a comparative example with sample numbers D2 to D5 as examples, the composition of the powder before calcination and the calcination temperature are appropriately selected, so that the breakdown voltage is also reduced. It was confirmed that it could be improved.

  Also, by observing the results of sample numbers C1 to C10 and D1 to D9, when the powder before calcination contains the fourth subcomponent, the calcination temperature is 500 ° C. or more and less than 1200 ° C., preferably It was confirmed that 600 to 900 ° C. was preferable. Also, by observing the results of sample numbers A1 to A10, if the raw material of the fourth subcomponent is not contained in the powder before calcining, the calcining temperature is preferably 600 to 1300 ° C. It was confirmed that the temperature was more preferably 900 to 1300 ° C, and particularly preferably 1000 to 1200 ° C.

  Further, by comparing sample numbers A1 to A10 and D1 to D9, the molar ratio of the components contained in the powder before calcination: (Ba + the metal element of the first component) / (Ti + the metal element of the fourth component) ) Is less than 1 or the molar ratio: (Ti + metal element of the fourth component) / (Ba + metal element of the first component) exceeds 1, it can be confirmed that the IR life and breakdown voltage characteristics are particularly improved. Was.

  Furthermore, by comparing the sample numbers F1 to F3, it was confirmed that it is preferable to use the calcined powder at 70% by weight or more, preferably 80% by weight or more, preferably 100% by weight of the whole dielectric material. Was. When the content was less than 70% by weight, it was confirmed that the DC-Bias characteristics were completely reduced.

  In addition, by observing the results of sample numbers E3 to E6, even when a Tb oxide or a Gd oxide is used as the fourth subcomponent, the calcining method according to the present invention does not satisfy the X7R characteristic, It was confirmed that various characteristics (particularly, IR life) were improved.

FIG. 1 is a sectional view of a multilayer ceramic capacitor.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode 10 ... Capacitor element main body

Claims (8)

Expressed by a composition formula _Ba m _{TiO 2 + n,} m in the composition formula is 0.995 ≦ m ≦ 1.010, n is 0.995 ≦ n ≦ 1.010, the ratio of Ba and Ti A main component satisfying 0.995 ≦ Ba / Ti ≦ 1.010;
A second auxiliary component, which is a sintering aid containing silicon oxide as a main component,
A method for producing a dielectric ceramic composition having at least other subcomponents,
Excluding the second sub-component, mixing the main component and at least a part of other sub-components, preparing a powder before calcination,
A step of calcining the powder before calcining to prepare a calcined powder,
A step of mixing at least the second subcomponent with the calcined powder to obtain a dielectric ceramic composition in which the ratio of each subcomponent to the main component is a predetermined molar ratio;
Has,
The other subcomponents,
A first auxiliary component containing at least one selected from MgO, CaO, BaO, SrO and Cr ₂ O ₃ ;
A third subcomponent including at least one kind selected from V ₂ O _5, MoO ₃ and WO _3,
A fourth subcomponent containing an oxide of R (where R is at least one selected from Y, Dy, Tb, Gd and Ho).
The calcined powder, at least the second sub-component is mixed, the ratio of each sub-component with respect to 100 mol of the main component,
First subcomponent: 0.1 to 3 mol,
Second subcomponent: 2 to 12 mol,
Third subcomponent: 0.1 to 3 mol,
Fourth subcomponent: 0.1 to 10.0 mol (however, the number of moles of the fourth subcomponent is a ratio of R alone),
Molar ratio of components contained in the powder before calcination: (Ba + metal element of first subcomponent) / (Ti + metal element of fourth subcomponent) is less than 1 or (Ba + metal element of fourth subcomponent) The pre-calcined powder is prepared so that) / (Ti + metal element of the first subcomponent) exceeds 1.
A method for producing a dielectric ceramic composition, wherein the powder before calcining is calcined at a temperature of 600C to 900C. 2. The dielectric ceramic composition according to claim 1, wherein the second subcomponent has a composition represented by (Ba, Ca) _x SiO _{2 + x} (where x = 0.8 to 1.2). 3. Manufacturing method. The other subcomponents,
Further comprising a fifth subcomponent containing MnO,
The calcined powder, at least the second sub-component is mixed, the ratio of each sub-component with respect to 100 mol of the main component,
First subcomponent: 0.1 to 3 mol,
Second subcomponent: 2 to 12 mol,
Third subcomponent: 0.1 to 3 mol,
Fourth subcomponent: 0.1 to 10.0 moles (however, the number of moles of the fourth subcomponent is a ratio of R alone),
The method for producing a dielectric ceramic composition according to claim 1, wherein a dielectric ceramic composition having a fifth subcomponent: 0.05 to 1.0 mol is obtained.   The dielectric porcelain composition according to any one of claims 1 to 3, wherein when preparing the powder before calcination, the powder before calcination always contains a first subcomponent. Manufacturing method.   The method for producing a dielectric ceramic composition according to any one of claims 1 to 4, wherein the calcination is performed a plurality of times.   The method for producing a dielectric ceramic composition according to any one of claims 1 to 5, wherein the average particle size of the main component is 0.1 to 0.7 µm.   The method for producing a dielectric ceramic composition according to any one of claims 1 to 6, wherein the calcined powder is used in an amount of 70% by weight or more, based on 100% by weight of the entire dielectric material. A method for producing a dielectric layer-containing electronic component, comprising forming a dielectric layer using the dielectric ceramic composition obtained by the method according to claim 1.

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