JP4862501B2 - Dielectric ceramic, manufacturing method thereof and multilayer ceramic capacitor - Google Patents

Description

  The present invention relates to a dielectric ceramic, a method for manufacturing the same, and a multilayer ceramic capacitor. More specifically, the present invention can prevent piezoelectric resonance and improve temperature characteristics (rate of change in capacitance due to temperature) and reliability. The present invention relates to a dielectric ceramic, a manufacturing method thereof, and a multilayer ceramic capacitor.

  As conventional dielectric ceramics and multilayer ceramic capacitors of this type, those proposed in Patent Documents 1 to 7, for example, are known.

Patent Document 1 proposes a multilayer capacitor. In this multilayer capacitor, the dielectric layer is composed of crystal grains mainly composed of BaTiO ₃ and grain boundaries between the crystal grains, and more than 80% of the total number of grain boundaries in the fracture surface of the dielectric layer. The grain boundary is made of an amorphous material containing Si, a rare earth element, an alkaline earth metal element, and oxygen. From this configuration, even when firing under a firing condition of Ni / NiO equal to or lower than the equilibrium oxygen partial pressure, excellent characteristics are exhibited at a high temperature load life.

  Patent Document 2 proposes a dielectric ceramic and a manufacturing method thereof. This dielectric porcelain is a dielectric porcelain containing Ba, Ti, Mn, Y and Mg, and contains main crystal particles made of a perovskite complex oxide containing at least Ba and Ti, and at least Y and Mg The Mn is substantially present only in the main crystal grains. From this configuration, since Mn exists only in the main crystal particles, solid solution of Mg and Y in the main crystal particles is suppressed, the sinterability is improved, and firing can be performed at a low temperature of 1200 ° C. or less. At the same time, since Mn exists only in the main crystal grains, the dielectric ceramic exhibits high insulation resistance.

Patent Document 3 proposes a dielectric ceramic and a multilayer electronic component. This dielectric ceramic is a dielectric ceramic composed of main crystal particles made of a perovskite complex oxide containing Ba, Ti, rare earth elements, Mg and Mn, and a grain boundary phase. And a crystal phase composed of a complex oxide containing rare earth elements and Si. From this configuration, the presence of γ-Y ₂ Si ₂ O ₇ as a crystal phase can improve the reliability in a high-temperature load test even if the layer is thinned.

Patent Document 4 proposes a dielectric ceramic and its manufacturing method, and a multilayer electronic component and its manufacturing method. This dielectric ceramic is a dielectric ceramic composed of main crystal particles made of a perovskite type complex oxide containing Ba, Ti, rare earth elements, Mg, and Mn, and a grain boundary phase. At least the M ₄ R ₆ O (SiO ₄ ) type crystal phase (M is an alkaline earth element and R is a rare earth element) is precipitated at the triple point. With this configuration, by forming a unique crystal phase in the triple-point grain boundary phase that is easy to discharge and has a significant decrease in dielectric breakdown resistance, the insulation, reliability at high temperature load, and temperature characteristics are improved.

Patent Document 5 proposes a dielectric ceramic, a manufacturing method thereof, and a multilayer ceramic capacitor. This dielectric ceramic is a dielectric ceramic containing ABO ₃ (A: Ba, Ca, Sr. B: Ti, Zr, Hf) as a main component and further containing a rare earth element and Si. At least a part of the rare earth element and Si A crystalline composite oxide in which at least a part of is different from the main component is formed. From this configuration, the temperature characteristics do not deteriorate as the thickness is reduced, and a dielectric ceramic and multilayer ceramic capacitor having excellent reliability can be obtained.

Patent Document 6 proposes a method for producing a dielectric ceramic composition and a method for producing a dielectric layer-containing electronic component. This dielectric ceramic composition includes a first subcomponent (Mg and alkaline earth metal oxide), a third subcomponent excluding a main component BaTiO ₃ and a second subcomponent serving as a sintering aid containing silicon oxide. It is obtained by calcining other than the components (oxides of V, Mo, W) and the fourth subcomponent (rare earth oxide). With this configuration, variation in composition is reduced, segregation phase precipitation control and size control are possible, and temperature characteristics, capacity change with time, insulation, and reliability at high temperature loads are improved.

  Patent Document 7 proposes a dielectric ceramic and a multilayer electronic component. This dielectric porcelain comprises perovskite-type barium calcium zirconate titanate crystal particles (1) in which a part of A site is substituted with Ca and perovskite-type barium calcium zirconate titanate in which a part of B site is substituted with Zr. The grain boundary between the crystal grains (2) includes an amorphous layer having a layer thickness of 1 nm or less, containing at least one element of Mn, Ca, Mg, and Ba, a rare earth element, and Si.

Japanese Patent No. 3389408 JP 2000-335966 A JP 2002-265260 A JP 2004-107200 A JP 2004-155649 A JP 2004-217520 A JP 2005-022890 A

  However, in the case of the multilayer capacitor described in Patent Document 1, since it is necessary to melt the additive in the firing process, the reaction between the main component and the additive tends to proceed, and the piezoelectric resonance is suppressed after the DC voltage is applied. In addition, it is difficult to control the capacity-temperature characteristics. Furthermore, since rare earth elements and Si and Mg are simultaneously calcined when the additive is produced, it is not possible to suppress the formation of Mg and Si complex oxides with low reliability.

  In the case of the dielectric ceramic described in Patent Document 2, since the Mn is dissolved in the main crystal, the absolute amount of Mn in the grain boundary region is insufficient and the reliability is lowered, and remains after the DC voltage is applied. Piezoelectric resonance cannot be suppressed. In addition, since Mg and Si are added as oxides alone, a composite oxide of Mg and Si having a low melting point is formed after firing, and the formation of a composite oxide of Mg and Si with low reliability is generated. It cannot be suppressed.

  In the case of the dielectric ceramics described in Patent Documents 3 and 5, in a complex oxide composed of only rare earth elements and Si, characteristics such as high temperature load reliability suddenly occur when crystals grow by sintering in a reducing atmosphere. It is not possible to obtain sufficiently high reliability.

  Further, in the case of the dielectric ceramic described in Patent Document 4, since rare earth elements, Si and Mg are not reacted in advance, a composite oxide of Mg and Si having a low melting point is generated after firing. Therefore, it is not possible to suppress the formation of Mg and Si composite oxide having a low content.

  Further, in the case of the dielectric ceramic described in Patent Document 6, since Si is not previously reacted with a rare earth element or Mg, a stable complex oxide of rare earth element, Mg, Si, and Mn cannot be obtained after firing. Can't get enough high reliability.

  In the case of the dielectric ceramic described in Patent Document 7, an amorphous layer is included in the grain boundary between the perovskite-type barium calcium zirconate titanate crystal particles (1) and (2), so that desired reliability is ensured. Can not do it.

  The present invention has been made to solve the above-mentioned problems, and is a dielectric ceramic that can prevent piezoelectric resonance and is excellent in high-temperature load reliability and that can obtain good temperature characteristics, a method for manufacturing the same, and The object is to provide a multilayer ceramic capacitor.

As a result of various studies on dielectric ceramics containing BaTiO ₃ -based perovskite crystal as a main component and R, Mg, and Si as subcomponents, the inventors have found that R, Mg, and Si are Mg oxides and Mg-Si. The present inventors have found that when it is present as —O composite oxide, the reliability is lowered, and when R, Mg, and Si are present as at least R—Mg—Si—O composite oxide, the reliability is not lowered.

  Further, it was found that the Mg—Si—O composite oxide remains in the sintered body with the final main component by simply mixing and reacting each of the R, Mg, and Si compounds. Further, even when the R-Si-O composite oxide synthesized in advance, the Mg compound, and the main component are reacted in the firing step, the R-Si-O composite oxide and the Mg compound do not sufficiently react, and Mg oxidation It was found that the reliability remained due to the remaining objects. Further, it has been found that the reliability similarly decreases even when the R-Mg-O composite oxide synthesized in advance, the Si compound, and the main component are reacted in the firing stage. Therefore, the present inventors can stably present the R-Mg-Si-O composite oxide in the perovskite type crystal by reacting each compound of R, Mg, and Si in a specific procedure, It has been found that the piezoelectric resonance can be suppressed and the temperature characteristics and the like can be improved.

The present invention has been made on the basis of the above knowledge, and the dielectric ceramic according to claim 1 is made of ABO ₃ (where the A site contains at least Ba of Ba, Ca, and Sr, and the B site contains Ti. , Zr, Hf represents a perovskite-type crystal containing at least Ti.) Rare earth element R (where R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb) , Dy, Ho, Er, Tm, Yb, Lu)), a dielectric ceramic containing Mg, Si, and Mn, the main component being a crystalline composite oxide composed of at least R, Mg, Si, and Mn And the content molar ratio of R, Mg, Si in the crystalline composite oxide is represented by x: y: z, x, y, z is A (42, 8, 50 ), B (8, 42, 5 ), C (8, 8, 84) is in a range surrounded by a triangle with the apex at 3 points (however, the component on BC line and the component on AC line are included, but the component on AB line is not included) It is a feature.

The dielectric ceramic according to claim 2 of the present invention is the dielectric ceramic according to claim 1, wherein the content of the subcomponent with respect to 100 mol parts of the main component ABO ₃ is such that R is 4 to 20 mol parts, and Mg is 2 to 15 mol parts, Si is 2 to 15 mol parts, and Mn is 0.5 to 5.0 mol parts.

The dielectric ceramic according to claim 3 of the present invention is the invention according to claim 1 or claim 2, with respect to the main component _ABO 3 100 molar parts, M (Cr, V, Fe , Co, Ni, Cu, Nb, Mo, and W are included) in an amount of 0.5 to 5.0 mole parts.

The dielectric ceramic according to claim 4 of the present invention is the invention according to any one of claims 1 to 3, wherein a part of Ti is substituted with Zr and Hf at the B site of the main component. In this case, the molar ratio is 0.98 ≦ Ti / (Zr + Ti + Hf) ≦ 1.00.

According to a fifth aspect of the present invention, there is provided a dielectric ceramic manufacturing method comprising: ABO ₃ (where the A site includes at least Ba of Ba, Ca, and Sr, and the B site includes at least Ti of Ti, Zr, and Hf). A perovskite-type crystal), a step of reacting at least a rare earth element compound and a silicon compound, and preparing a reactant A having crystallinity in a part thereof, and a reactant having the crystallinity. A step of reacting A with a magnesium compound and preparing a reactant B having crystallinity in a part thereof, mixing the ABO ₃ , the reactant B having crystallinity, and a manganese compound to obtain a ceramic raw material powder And a step of baking the ceramic raw material powder.

According to a sixth aspect of the present invention, there is provided a multilayer ceramic capacitor comprising a plurality of laminated dielectric ceramic layers and a plurality of dielectric ceramic layers formed along a specific interface between the dielectric ceramic layers so as to obtain capacitance. A multilayer ceramic capacitor comprising an internal electrode and an external electrode electrically connected to a specific one of the internal electrodes, wherein the dielectric ceramic layer is any one of claims 1 to 4. It is formed by the dielectric ceramic described in the item.

Thus, the dielectric ceramic of the present invention has ABO ₃ as a main component (provided that the A site contains at least Ba of Ba, Ca and Sr, and the B site contains at least Ti of Ti, Zr and Hf). A rare earth element R as a subcomponent (where R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). Represents at least one kind of Mg), Mg, Mn, and Si.

  The A site includes at least Ba of Ba, Ca, and Sr, and the B site is configured as a perovskite crystal including at least Ti of Ti, Zr, and Hf. The A site basically includes Ba, and a part of Ba may be replaced with at least one of Ca and Sr. Further, the B site may basically contain Ti, and a part of Ti may be substituted with at least one of Zr and Hf.

  Rare earth element R (wherein R represents at least one of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). Each of Mg, Mn and Si is basically an additive for improving the dielectric constant, temperature characteristics, Curie temperature and other characteristics of the dielectric material.

  The dielectric ceramic of the present invention has secondary phase particles, and the secondary phase particles contain at least a crystalline composite oxide composed of at least rare earth elements R, Mg, Si and Mn as a main component. Furthermore, the content ratio of R, Mg, Si in the crystalline composite oxide is such that when each molar ratio is represented by a ternary system of x, y, z, as shown in FIG. (42,8,50), B (8,42,50), C (8,8,84) surrounded by a triangle with vertices (however, the component on the BC line, the component on the AC line) Is included, but the component on the AB line is not included). That is, x, y, and z satisfy x + y + z = 1, and satisfy the relationship of 8 ≦ x <42, 8 ≦ y <42, and 50 <z ≦ 84. When the secondary phase particles R, Mg, and Si satisfy this condition, a ceramic structure capable of suppressing piezoelectric resonance after application of a DC voltage can be obtained even if the dielectric ceramic is thinned.

  In other words, even if the secondary phase particles have crystallinity, it is difficult to suppress piezoelectric resonance if the content ratio of R, Mg, Si does not satisfy the above conditions, and R, Mg, Even if the Si content ratio satisfies the above conditions, it is difficult to suppress piezoelectric resonance unless Mn is present. Mn is preferably contained in an amount of 0.2 parts by weight or more based on 100 parts by weight of the composite oxide of R, Mg and Si. A crystalline composite oxide composed of R, Mg, Si, and Mn that satisfies the above conditions can be formed, for example, by the production method of the present invention described later.

In addition, the content of subcomponents with respect to 100 mol parts of the main component ABO ₃ is as follows: R is 4 to 20 mol parts, Mg is 2 to 15 mol parts, Si is 2 to 15 mol parts, and Mn is 0.5 to 5.0. The molar part is preferred. When the contents of R, Mg, Si and Mn with respect to ABO ₃ satisfy this condition, the high temperature load characteristic can be further improved and the temperature characteristic can be improved.

  If the R content is less than 4 mole parts, the temperature characteristics are lowered, and the reliability for the high temperature load test is slightly lowered. If the R content exceeds 20 mole parts, the reliability for the high temperature load test is lowered. However, even if the R content deviates from this range, the reliability of temperature characteristics and high temperature load tests can be ensured by reducing the rated voltage to ensure the reliability of practical temperature characteristics and high temperature load tests. it can.

  If the Mg content is less than 2 mole parts, the temperature characteristics are lowered, and the reliability for the high temperature load test is slightly lowered. If the Mg content exceeds 15 mole parts, the reliability for the high temperature load test is lowered. However, even if the Mg content deviates from this range, the reliability of temperature characteristics and high temperature load tests can be ensured by reducing the rated voltage to ensure the practical temperature characteristics and reliability for high temperature load tests. it can.

  If the Si content is less than 2 mol parts, the temperature characteristics are lowered, and the reliability for the high temperature load test is slightly lowered. If the Si content exceeds 15 mol parts, the reliability for the high temperature load test is lowered. However, even if the Si content deviates from this range, the reliability of temperature characteristics and high temperature load tests can be ensured by reducing the rated voltage to ensure the reliability of practical temperature characteristics and high temperature load tests. it can.

  When the Mn content is less than 0.5 mol part, the reliability for the high temperature load test is slightly lowered, and the temperature characteristics are also somewhat lowered. When the content of Mn exceeds 5 mol parts, the reliability with respect to the high temperature load test decreases. However, even if the Mn content deviates from this range, the reliability of temperature characteristics and high-temperature load tests can ensure the reliability of practical temperature characteristics and high-temperature load tests by reducing the rated voltage. it can.

It is preferable to contain 0.5 to 5.0 mole parts of M with respect to 100 mole parts of the main component ABO ₃ . By adding M in this range, the reliability for the high temperature load test can be further increased. As M, at least one of Cr, V, Fe, Co, Ni, Cu, Nb, Mo and W can be appropriately selected and used, or two or more may be appropriately selected and used.

  When a part of Ti is substituted by Zr and Hf at the B site of the main component, it is preferable that a molar ratio of 0.98 ≦ Ti / (Zr + Ti + Hf) ≦ 1.00 is satisfied. When the above relationship is established, the temperature characteristics can be further improved without reducing the dielectric constant.

Next, an example of a method for producing a dielectric ceramic according to the present invention will be described. In the present invention, in the step of preparing ABO ₃ , the A site includes at least Ba of Ba, Ca, and Sr, and the B site includes a perovskite crystal including at least Ti of Ti, Zr, and Hf. Prepare as the main ingredient. That is, ABO ₃ has a basic composition of BaTiO ₃ , and a part of Ba at the A site is replaced with at least one of Ca and Sr, or Ti at the B site is replaced with at least one of Zr and Hf. Prepare one. You may prepare what substituted both A site and B site simultaneously.

The main component ABO ₃ has R as a subcomponent (where R represents at least one of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. ), Mg, Si, and Mn. At this time, it is necessary to form secondary phase particles mainly composed of a crystalline composite oxide composed of at least R, Mg, Si and Mn in the dielectric ceramic. When Mg oxide or Mg—Si—O composite oxide exists in a dielectric ceramic containing ABO ₃ as a main component, for example, if a multilayer ceramic capacitor is produced using this dielectric ceramic, piezoelectric resonance can be suppressed. This is not possible and the reliability for the high temperature load test is reduced. However, if it exists as a crystalline composite oxide composed of R, Mg, Si, and Mn, the piezoelectric resonance can be suppressed, and the reliability for the high-temperature load test is increased.

  Therefore, in the present invention, before adding R, Mg, Si and Mn as subcomponents, at least a rare earth element (R) compound and a silicon (Si) compound are reacted, and a reaction product having crystallinity in a part thereof. A step of preparing A is provided. In this step, an R—Si—O composite oxide is prepared in advance as the reactant A. Furthermore, the method includes a step of reacting an R—Si—O composite oxide having crystallinity with a magnesium (Mg) compound and preparing a reactant B having crystallinity in a part thereof. In this step, the R—Si—Mg—O composite oxide can be stably and reliably obtained as the reactant B.

In the step of preparing ceramic raw material powder by mixing ABO ₃ , R-Si-Mg-O composite oxide having crystallinity, and manganese (Mn) compound, the ceramic raw material powder of the dielectric ceramic of the present invention is prepared. obtain. In the step of firing the ceramic raw material powder, the ceramic raw material powder is sintered as a dielectric ceramic, and there are secondary phase particles mainly composed of a crystalline composite oxide composed of R, Mg, Si and Mn. The reliability of the dielectric ceramic can be ensured. The content ratio of R, Mg, Si in the R—Mg—Si—O composite oxide in the final dielectric ceramic must be adjusted in advance so that the molar ratio falls within the above-mentioned triangular range.

  Unlike R, Mg, and Si, Mn is not particularly limited in its addition time and reaction time. For example, a step of preparing an R—Si—O composite oxide, a step of reacting an R—Si—O composite oxide and an Mg compound, or a step of mixing an R—Mg—Si—O composite oxide and a main component. May be added.

  Since the multilayer ceramic capacitor of the present invention uses the dielectric ceramic of the present invention as a dielectric material, temperature characteristics and high-temperature load reliability are improved, and there is almost no piezoelectric resonance.

  ADVANTAGE OF THE INVENTION According to this invention, the dielectric ceramic which can prevent a piezoelectric resonance, is excellent in high temperature load reliability, and can acquire a favorable temperature characteristic, its manufacturing method, and a multilayer ceramic capacitor can be provided.

  Hereinafter, an embodiment of the multilayer ceramic capacitor of the present invention will be described with reference to FIG. For example, as shown in FIG. 2, the multilayer ceramic capacitor 1 of the present embodiment includes a plurality of dielectric ceramic layers 2 and a plurality of first and second internal electrodes 3 </ b> A disposed between the dielectric ceramic layers 2. 3B, and first and second external electrodes 4A and 4B electrically connected to the internal electrodes 3A and 3B and formed at both ends of the multilayer body.

  The first internal electrode 3A extends from one end (left end in the figure) of the dielectric ceramic layer 2 to the vicinity of the other end (right end), and the second internal electrode 3B extends from the right end of the dielectric ceramic layer 2 to the vicinity of the left end. ing. The first and second internal electrodes 3A and 3B are made of a conductive material. As the conductive material, for example, metals such as nickel, nickel alloy, copper, copper alloy, silver, silver alloy can be preferably used. In order to prevent structural defects of the internal electrodes, a small amount of ceramic powder may be added in addition to the conductive material.

  The first external electrode 4A is electrically connected to the first internal electrode 3A in the multilayer body, and the second external electrode 4B is electrically connected to the second internal electrode 3B in the multilayer body. The first and second external electrodes 4A and 4B can be formed of various conductive materials such as conventionally known Ag and copper. Moreover, conventionally well-known each means can be employ | adopted suitably for the formation means of 1st, 2nd external electrode 4A, 4B.

  In the case of the multilayer ceramic capacitor of this embodiment, since it can be fired in a reducing atmosphere, the internal electrode can be formed using a base metal such as nickel, nickel alloy, copper, or copper alloy.

  In Examples 1 to 5 below, the dielectric ceramic of the present invention used for the dielectric ceramic layer 2 is prepared, and the multilayer ceramic capacitor of the present invention is manufactured using the dielectric ceramic. Characteristics were evaluated.

Example 1
In this example, the influence of the molar ratio was examined by changing the molar ratio of R, Mg, and Si.
In this example, (Ba _0.97 Ca _0.01 Sr _0.02 ) _1.005 (Ti _0.98 Zr _0.02 ) O ₃ was used as ABO ₃ , and a rare earth element oxide (hereinafter referred to as an additive component). , “RO _x ”), MgO, SiO ₂ and MnO ₂ were used to prepare samples of Test Examples 1 to 18. Moreover, the sample of Comparative Examples 1-4 was produced for the comparison. Note that _x in RO _x is a positive number for maintaining electrical neutrality.

(1) Preparation of Main Component (Ba _0.97 Ca _0.01 Sr _0.02 ) _1.005 (Ti _0.98 Zr _0.02 ) O ₃ First, BaCO ₃ , CaCO ₃ , SrCO ₃ , After preparing each powder of TiO ₂ and ZrO ₂ and weighing these starting materials so as to have the composition of the main component, these starting materials are mixed by a ball mill, heat-treated at 1050 ° C. for 2 hours, After synthesizing the main component powder having a diameter of 0.15 μm, it was pulverized.

(2) Preparation of Subcomponent R—Mg—Si—O-based Reactant After adding rare earth oxides RO _x (one or more) and SiO ₂ as additive components to the composition shown in Table 1, The mixture was mixed by a ball mill and heat-treated at 1100 ° C. for 2 hours to obtain a RO _x —SiO ₂ reactant having an average particle size of 0.25 μm and pulverized. Further, the RO _x —SiO ₂ -based reactant and MgO were weighed so as to have the composition shown in Table 1, mixed by a ball mill, heat-treated at 1150 ° C. for 2 hours, and R-Mg— having an average particle size of 0.3 μm. A Si—O-based reactant was obtained and pulverized.

(3) Preparation of ceramic raw material powder (Ba _0.97 Ca _0.01 Sr _0.02 ) _1.005 (Ti _0.98 Zr _0.02 ) O ₃ and R—Mg—Si—O based reactant Ceramic raw powder was obtained by mixing with a ball mill. The content ratio of MnO ₂ was 1.5 parts by mole with respect to 100 parts by mole of the main component.

(4) Production of Multilayer Ceramic Capacitor A ceramic slurry was prepared by adding a polyvinyl butyral binder and an organic solvent such as ethanol to each ceramic raw material powder having the composition shown in Table 1 and wet mixing with a ball mill. These ceramic slurries were formed into a sheet shape by a doctor blade method so that the thickness of the dielectric ceramic layer after firing was 2 μm to obtain a rectangular ceramic green sheet. Next, a conductive paste containing nickel (Ni) as a conductive component was screen-printed on these ceramic green sheets to form a conductive paste layer for constituting internal electrodes.

A plurality of ceramic green sheets on which the conductive paste layer was formed were stacked so that the side from which the conductive paste was drawn was alternated and cut into a predetermined size to obtain a raw laminate. The raw laminate was heated to 350 ° C. in a nitrogen gas atmosphere to burn the binder, and then 1200 ° C. and an oxygen partial pressure of 10 ⁻⁹ in a reducing atmosphere composed of H ₂ —N ₂ —H ₂ O gas. A ceramic laminate was obtained by firing at MPa for 2 hours.

A Cu paste containing glass frit is applied to both end faces of the fired ceramic laminate, and the Cu paste is baked at a temperature of 700 ° C. in an N ₂ atmosphere to form an external electrode electrically connected to the internal electrode. Thus, multilayer ceramic capacitors of Test Examples 1 to 18 and Comparative Examples 1 to 4 were obtained.

The outer dimensions of the multilayer ceramic capacitor thus obtained are 1.6 mm in width, 3.2 mm in length, and 0.8 mm in thickness, respectively, and the dielectric ceramic layer interposed between the internal electrodes. The thickness was 2 μm. Furthermore, the total number of effective dielectric ceramic layers was 100, and the area of the counter electrode per layer was 2.1 mm ² .

(4) Characteristic Evaluation of Multilayer Ceramic Capacitor Each of the multilayer ceramic capacitors of Test Examples 1 to 18 and Comparative Examples 1 to 4 was measured for dielectric constant ε, temperature characteristics, high temperature load characteristics, and piezoelectric resonance, and the results are shown in Table 2. Indicated. Moreover, the ceramic structure was analyzed about the arbitrary fracture surface including the center part of a multilayer ceramic capacitor.

  The dielectric constant ε was measured under conditions of a temperature of 25 ° C., 1 kHz, and 1 Vrms. The change rate of the capacitance with respect to the temperature change is shown as a temperature characteristic at the change rate at 125 ° C. based on the capacitance at 25 ° C.

  In the high temperature load test, a voltage of 30 V was applied at a temperature of 150 ° C., and the change over time in the insulation resistance was measured. The high temperature load test was performed on 200 multilayer ceramic capacitors, and a sample having an insulation resistance value of 100 kΩ or less before 1000 hours was judged as a failure.

  Piezoelectric resonance was measured after applying a DC voltage of 20 V at room temperature for 100 hours. The measuring instrument used was 4194A manufactured by Agilent. The frequency range was 1 KHz-10 MHz, and the AC voltage was 0.1 Vrms. In the frequency characteristics of the impedance, a resonance-antiresonance waveform was observed, and it was determined that the piezoelectric resonance was present when the ratio of the impedance at the antiresonance frequency to the impedance at the resonance frequency was 100 or more.

  Further, for the analysis of the ceramic structure, the composition of secondary phase particles was confirmed using wavelength dispersion X-ray analysis (WDX). The value of R: Mg: si ratio in Table 2 is an average of the measured values of 20 secondary phase particles.

According to the results shown in Table 2, the following were found.
In Test Examples 1 to 18 in this example, R-Mg-Si-O oxide is stably prepared by preparing a composite oxide composed of R and Si and further reacting with MgO (Mg compound). In addition, by setting the molar ratio of R: Mg: Si included in the range of the triangle shown by hatching in FIG. 1 at the firing stage, oxides of R, Mg, and Si each of these three elements It was possible to suppress the generation of complex oxides consisting of only two of them, and to suppress the decrease in reliability. Further, after preparing a complex oxide composed of R, Si, and Mg in advance, the main component (Ba _0.97 Ca _0.01 Sr _0.02 ) _1.005 (Ti _0.98 Zr _0.02 ) O ₃ Therefore, the diffusion of R and Mg into the main phase phase particles and secondary phase particles can be easily controlled, and the piezoelectric resonance can be suppressed.

  On the other hand, in Comparative Examples 1 to 4, since the composition ratio of R, Mg, and Si in the secondary particle phase is outside the range of the triangle shown by hatching in FIG. 1, the reliability is lowered and the piezoelectric resonance remains. did.

Example 2
In this example, the influence of the dielectric ceramic manufacturing method was examined.
In this example, (Ba _0.985 Ca _0.01 Sr _0.005 ) _1.007 (Ti _0.985 Zr _0.01 Hf _0.005 ) O ₃ was used as ABO _{3 and} RO _x was used as an additive component. Samples of Test Examples 19 and 20 were prepared using MgO, SiO ₂ and MnO ₂ . As described below, Test Example 20 was prepared in the same manner as Test Example 19 except that the timing of adding MnO ₂ was different when preparing the ceramic raw material powder of Test Example 19.

(1) Preparation of main component (Ba _0.985 Ca _0.01 Sr _0.005 ) _1.007 (Ti _0.985 Zr _0.01 Hf _0.005 ) O _{3 As} starting materials BaCO ₃ , SrCO ₃ , CaCO _{3, TiO} 2, and prepare each powder of ZrO ₂ and HfO _2, after these starting materials were weighed so that the main component, these starting materials were mixed by a ball mill, subjected to heat treatment for 2 hours at 1150 ° C. The above main component powder having an average particle size of 0.25 μm was synthesized and then pulverized.

(2) Preparation of subcomponent R—Mg—Si—O-based reactant As additive components, 12 mol of DyO _{3/2 and} 8 mol of SiO ₂ were weighed, mixed by a ball mill, heat treated at 1100 ° C., and average grain size A Dy—Si—O-based reaction product having a diameter of 0.25 μm was obtained and pulverized. Further, after weighing Dy-Si-O-based reactant and 6 mol of MgO, they were mixed by a ball mill and heat-treated at 1150 ° C for 2 hours to obtain a Dy-Mg-Si-O-based reactant having an average particle size of 0.3 µm. Obtained.

(3) Preparation of ceramic raw material powder Dy is 100 mol of main component (Ba _0.985 Ca _0.01 Sr _0.005 ) _1.007 (Ti _0.985 Zr _0.01 Hf _0.005 ) O ₃ A Dy-Mg-Si-O-based reactant having 12 moles and 2 moles of MnO ₂ were mixed by a ball mill to obtain a ceramic raw material powder. This ceramic raw material powder was used as Test Example 19.

  Moreover, in Test Example 20, the timing of adding Mn was changed to the timing of preparing the ceramic raw material powder of (3), and was added at the stage of preparing the Dy-Mg-Si-O-based reactant of (2). Except for the above, a ceramic raw material powder was obtained in the same manner as in Test Example 19.

(4) Production of multilayer ceramic capacitor A multilayer ceramic capacitor was produced in the same manner as in Example 1 using the ceramic raw material powders of Test Examples 19 and 20, and the same evaluation as in Example 1 was performed for each multilayer ceramic capacitor. The results are shown in Table 3.

Preparation of Sample of Comparative Example 5 In Test Example 19, first, 6 mol of Dy ₂ O ₃ , 8 mol of SiO _{2 and} 6 mol of MgO were weighed, mixed by a ball mill, melted at 1500 ° C., and this melt was immersed in water. The glass cullet was thrown in, and this glass cullet was pulverized to prepare 12DyO _3/2 -8SiO ₂ -6MgO-based glass powder. Then, 12DyO _3/2 -8SiO _2- per 100 mol of the main component (Ba _0.985 Ca _0.01 Sr _0.005 ) _1.007 (Ti _0.985 Zr _0.01 Hf _0.005 ) O ₃ 1 mol of 6MgO-based glass powder and ₂ mol of MnO ₂ were weighed and then mixed by a ball mill to obtain a ceramic raw material powder. Thereafter, using this ceramic raw material powder, multilayer ceramic capacitors were produced in the same manner as in Test Examples 19 and 20, and the same evaluation as in Example 1 was performed for each multilayer ceramic capacitor. The results are shown in Table 3. It was.

Preparation of Sample of Comparative Example 6 In Test Example 19, 6 mol of Dy ₂ O ₃ , 8 mol of SiO ₂ , 6 mol of MgO _{2 and} 2 mol of MnO ₂ were weighed with respect to 100 mol of the main component, and then mixed by a ball mill, Raw material powder was obtained. Thereafter, using this ceramic powder, a multilayer ceramic capacitor was produced in the same manner as in Example 1. Each multilayer ceramic capacitor was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

In Preparation Test Example 19 of the sample of Comparative Example 7, with respect to 100 moles of the main component, _Dy 2 _{O 3} 6 mol, it was weighed MgO6 mole and MnO ₂ 2 mol, mixed by a ball mill, and dried, Dy ₂ A main component powder coated with O ₃ , MgO, MnO ₂ was obtained. 8 mol of SiO ₂ was mixed by a ball mill with respect to 100 mol of the coated main component to obtain a ceramic raw material powder. Thereafter, using this ceramic powder, a multilayer ceramic capacitor was produced in the same manner as in Example 1. Each multilayer ceramic capacitor was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Preparation of Sample of Comparative Example 8 In Test Example 19, the main components coated with MgO and MnO ₂ were weighed with 6 mol of MgO and ₂ mol of MnO _{2 with} respect to 100 mol of the main component, then mixed with a ball mill, dried. Ingredient powder was obtained. 6 mol of Dy ₂ O _{3 and} 8 mol of SiO ₂ were mixed by a ball mill with respect to 100 mol of the coated main component to obtain a ceramic raw material powder. Thereafter, using this ceramic powder, a multilayer ceramic capacitor was produced in the same manner as in Example 1. Each multilayer ceramic capacitor was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Preparation of Sample of Comparative Example 9 In Test Example 19, first, 6 mol of Dy ₂ O _{3 and} 8 mol of SiO ₂ were weighed, mixed by a ball mill, heat-treated at 1100 ° C. for 2 hours, and an average particle size of 0.25 μm. A Dy-Si-O-based reaction product was obtained and pulverized. Next, the Dy-Si-O-based reactant, 8 mol of MgO, and ₂ mol of MnO ₂ were weighed with respect to 100 mol of the main component, and then mixed by a ball mill to obtain a ceramic raw material powder. Thereafter, using this ceramic powder, a multilayer ceramic capacitor was produced in the same manner as in Example 1. Each multilayer ceramic capacitor was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Preparation of Sample of Comparative Example 10 In Test Example 19, first, 6 mol of Dy ₂ O _{3 and} 6 mol of MgO were weighed, mixed by a ball mill, heat-treated at 1100 ° C. for 2 hours, and Dy− having an average particle diameter of 0.25 μm. An Mg—O-based reactant was obtained and pulverized. After weighing 2 mol of MnO ₂ with respect to this Dy-Mg-O-based reactant, it was mixed by a ball mill and heat-treated at 1150 ° C. for 2 hours to obtain a Dy-Mg-Mn—O-based reaction having an average particle size of 0.30 μm. A product was obtained and ground. Then, to obtain a ceramic raw material powder composed mainly powder and Dy-Mg-Mn-O-based reaction products with SiO ₂ 8 mol were mixed by a ball mill. Thereafter, using this ceramic powder, a multilayer ceramic capacitor was produced in the same manner as in Example 1. Each multilayer ceramic capacitor was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Preparation of Sample of Comparative Example 11 In Test Example 19, first, 8 mol of SiO _{2 and} 6 mol of MgO were weighed, mixed by a ball mill, heat-treated at 1050 ° C. for 2 hours, and Si—Mg— having an average particle size of 0.20 μm. An O-based reactant was obtained and pulverized. Next, the main component powder, Si—Mg—O-based reactant, 6 mol of Dy ₂ O ₃ and ₂ mol of MnO ₂ were mixed by a ball mill to obtain a ceramic raw material powder. Thereafter, using this ceramic powder, a multilayer ceramic capacitor was produced in the same manner as in Example 1. Each multilayer ceramic capacitor was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

Preparation of Sample of Comparative Example 12 In Test Example 19, first, 6 mol of Dy ₂ O ₃ , 8 mol of SiO ₂ , and 6 mol of MgO were weighed, mixed by a ball mill, and heat-treated at 1150 ° C. for 2 hours. A 20 μm Dy-Mg-Si-O-based reaction product was obtained and pulverized. Next, the main component powder, Dy-Mg-Si-O-based reactant and 2 mol of MnO ₂ were mixed by a ball mill to obtain a ceramic raw material powder. Thereafter, using this ceramic powder, a multilayer ceramic capacitor was produced in the same manner as in Example 1. Each multilayer ceramic capacitor was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

According to the results shown in Table 3, the following were found.
In Test Example 19 of this example, a composite oxide composed of R and Si was prepared, and then Mg was reacted to obtain an R—Mg—Si—O-based reactant, whereby R, Si, It was possible to suppress the formation of a single oxide of Mg and a composite oxide composed of only two of these three elements, and to suppress a decrease in reliability. In addition, since a composite oxide composed of R, Si, and Mg is prepared and reacted with the main component in advance, it becomes easier to control the diffusion of R and Mg into the main component particles and secondary phase particles, thereby suppressing piezoelectric resonance. We were able to. In Test Example 20 of this example, it was found that there was no problem even if Mn was added in advance at the reaction product preparation stage and allowed to react.

  Compared to Test Examples 19 and 20 of this example, in Comparative Example 5, the secondary phase particles did not have crystallinity, so the reliability was low and piezoelectric resonance could not be suppressed. In Comparative Example 6, since Mn was dissolved in the main component particles, solid solution of R and Mg in the main component particles was suppressed, and piezoelectric resonance could not be suppressed. In Comparative Examples 7 and 8, Mg-Si-O-based compounds with low reliability, that is, secondary phases that deviate from the triangular range shown by hatching in FIG. did. In Comparative Example 9, since the R—Si—O-based compound having low reliability, that is, a secondary phase that deviates from the triangular range shown by hatching in FIG. 1 is preferentially generated, the reliability deteriorated. In Comparative Example 10, when the Dy-Mg-Mn-O-based compound and Si react with each other, an unreliable Mg-Si-O-based compound is generated. Since the secondary phase was preferentially generated, the reliability deteriorated. In Comparative Example 11, a low-reliability Mg—Si—O-based compound, that is, a secondary phase that deviates from the triangular range shown by hatching in FIG. In Comparative Example 12, since the Dy-Mg-Si-O-based compound was not sufficiently stable, there was a secondary phase that deviated from the range of the triangle indicated by the diagonal lines in FIG.

Example 3
In this example, the influence of the composition of the entire dielectric ceramic was examined.
In this example, (Ba _0.995 Ca _0.005 ) _m (Ti _0.995 Zr _0.005 ) O ₃ is used as ABO ₃ , and RO _x , MgO, SiO ₂ and MnO ₂ are used as additive components. Te, papermaking create the sample of test example 21-47.

(1) Preparation of main component (Ba _0.995 Ca _0.005 ) _m (Ti _0.995 Zr _0.005 ) O ₃ Prepare powders of BaCO ₃ , CaCO ₃ , TiO ₂ and ZrO ₂ as starting materials. These starting materials are weighed so that m of the main component is the value shown in Table 4, and then these starting materials are mixed by a ball mill and heat-treated at 1150 ° C. for 2 hours, with an average particle size of 0.25 μm. After the above main component powder was synthesized, it was pulverized.

(2) Preparation of subcomponent R—Mg—Si—O-based reactant As additive components, RO _3/2 and SiO ₂ were weighed so as to have the composition shown in Table 4, and then mixed by a ball mill at 1100 ° C. Heat treatment was performed for 2 hours to obtain an R—Si—O-based reaction product having an average particle size of 0.20 μm and pulverized. Further, the R—Si—O-based reactant and MgO were weighed so as to have the composition shown in Table 4, then mixed by a ball mill, heat-treated at 1150 ° C. for 2 hours, and R-Mg having an average particle size of 0.25 μm. A —Si—O-based reaction product was obtained.

(3) Preparation of Ceramic Raw Material Powder Main components (Ba _0.995 Ca _0.005 ) _m (Ti _0.995 Zr _0.005 ) O ₃ , R—Mg—Si—O based reactant and MnO ₂ are shown in Table 4. After weighing so as to have the composition shown in FIG. 1, the mixture was mixed by a ball mill to obtain a ceramic raw material powder.

(4) Production of multilayer ceramic capacitor A multilayer ceramic capacitor was produced in the same manner as in Example 1 using the ceramic raw material powders of Test Examples 21 to 47 , and the same evaluation as in Example 1 was performed for each multilayer ceramic capacitor. The results are shown in Table 4.

  In the test example and the comparative example shown in Table 4, a crystalline composite oxide composed of at least R—Mg—Si—O exists between the internal electrodes, and the moles of R, Mg, Si in the crystalline composite oxide. There was virtually no secondary phase with a molar ratio that was outside the range of the triangles shown in slash in FIG.

According to the results shown in Table 4, the following were found.
In Test Examples 21 to 37 of this example, in addition to no piezoelectric resonance, the defect rate of the high temperature load test was 1/200 or less, and the absolute value of the temperature characteristic was 22% or less. Further, from the results of Test Examples 25 to 30, even when a plurality of rare earth elements were added in any combination, the characteristics were not affected.

To the test examples 21 to 37 of the present embodiment, m is reduced Test Example 38 In the temperature characteristic of less than 1.000, also slightly reduced reliability, in Test Example 39 m is more than 1.020, Reliability was slightly reduced. In Test Example 40 where R was less than 4 mol, the temperature characteristics were lowered and the reliability was slightly lowered. In Test Example 41 in which R exceeds 20 mol, the reliability slightly decreased. In Test Example 42 in which Mg was less than 2 mol%, the temperature characteristics were lowered and the reliability was slightly lowered, and in Test Example 43 in which Mg was more than 15 mol%, the reliability was slightly lowered. In Test Example 44 in which Si was less than 2 mol%, the reliability was slightly lowered, and in Test Example 45 in which Si was more than 15 mol%, the temperature characteristics were lowered, and the reliability was slightly lowered. In Test Example 46 where Mn was less than 0.5 mol%, the reliability was slightly lowered, and the temperature characteristics were also slightly lowered, and in Test Example 47 where Mn was more than 5 mol%, the reliability was slightly lowered. However, in any of Test Examples 38 to 47 , it is possible to obtain temperature characteristics and reliability of a practically necessary level by lowering the rated voltage.

Example 4
In this example, the influence of the additive M was examined.
In this example, (Ba _0.99 Sr _0.01 ) _1.011 (Ti _0.99 Zr _0.01 ) O ₃ was used as ABO ₃ , and Dy _3/2 , MgO, SiO ₂ and with MnO _2, papermaking create samples of test examples 48-63.

(1) Preparation of main component (Ba _0.99 Sr _0.01 ) _1.011 (Ti _0.99 Zr _0.01 ) O ₃ BaCO ₃ , SrCO ₃ , TiO ₂ and ZrO ₂ powders were used as starting materials. After preparing and weighing these starting materials so as to have the composition of the main component, the starting materials are mixed by a ball mill and heat-treated at 1150 ° C. for 2 hours, and the main component having an average particle size of 0.25 μm. After the powder was synthesized, it was pulverized.

(2) Preparation of Subcomponent Dy-Mg-Si-O-Based Reactant As additional components, DyO _3/2 16 mol and SiO ₂ 7 mol were weighed with respect to 100 mol of the main component, and then mixed by a ball mill. Heat treatment was performed at 0 ° C. for 2 hours to obtain a Dy—Si—O-based reaction product having an average particle size of 0.25 μm and pulverized. Further, after weighing Dy-Si-O-based reactant and 5.5 mol of MgO, they were mixed by a ball mill, heat-treated at 1150 ° C for 2 hours, and Dy-Mg-Si-O-based having an average particle size of 0.3 µm. A reaction product was obtained.

(3) Preparation of ceramic raw material powder Main component (Ba _0.99 Sr _0.01 ) _1.011 (Ti _0.99 Zr _0.01 ) O ₃ , Dy—Mg—Si—O based reactant, MnO ₂ 1 Then, 5 mol and M oxide were weighed so as to have the composition shown in Table 5, and then mixed by a ball mill to obtain a ceramic raw material powder.

(4) Production of multilayer ceramic capacitor A multilayer ceramic capacitor was produced in the same manner as in Example 1 using the ceramic raw material powders of Test Examples 48 to 63 , and the same evaluation as in Example 1 was performed for each multilayer ceramic capacitor. The results are shown in Table 5. In the high-temperature load test, failure was determined not only after 1000 hours but also after 2000 hours.

Incidentally, Oite Test Example shown in Table 5, crystalline composite oxide of at least R-Mg-Si-O is present between the internal electrodes, R in its crystalline composite oxide: Mg: Si molar ratio of However, there was substantially no secondary phase with a molar ratio outside the range of the triangle shown in FIG.

According to the results shown in Table 5, the following were found.
In Test Examples 48 to 60 of this example, the reliability could be further improved by adding M in the range of 0.5 mol to 5.0 mol. Even after 2000 hours had passed in the high temperature load test, the defect rate was 1/200 or less.

In Test Examples 61 to 63 in which the amount of addition of M deviates from the above range, the defective product rate after 2000 hours in the high temperature load test was high.

Example 5
In this example, the influence of the Ti content at the main B site was examined.
In this embodiment, as ABO _3, using _{(Ba 0.99 Ca 0.01) (Ti} , Zr, Hf) a _{O 3} used, _DyO 3/2 as an additive component, MgO, SiO ₂ and MnO _2, a sample of the test examples 64-66 papermaking work.

(1) Preparation of main component (Ba _0.99 Ca _0.01 ) _1.008 (Ti _x Zr _1-x ) O ₃ Prepare powders of BaCO ₃ , CaCO ₃ , TiO ₂ and ZrO ₂ as starting materials. These starting materials were weighed so as to have the composition shown in Table 6, and then these starting materials were mixed by a ball mill and heat-treated at 1150 ° C. for 2 hours to obtain the above main component powder having an average particle diameter of 0.25 μm. After synthesis, it was pulverized.

(2) Preparation of subcomponent Dy-Mg-Si-O-based reactants DyO _3/2 12 mol and SiO ₂ 5 mol were weighed as additive components, mixed by a ball mill, and heat treated at 1100 ° C. for 2 hours. A Dy—Si—O-based reaction product having an average particle diameter of 0.25 μm was obtained and pulverized. Further, the Dy-Si-O-based reactant and 5 mol of MgO were weighed, mixed by a ball mill, heat-treated at 1150 ° C for 2 hours, and a Dy-Mg-Si-O-based reactant having an average particle size of 0.3 µm. Got.

(3) Preparation main component of the ceramic raw material powder, Dy-Mg-Si-O-based reactants, were weighed so that the _MnO 2 1.0 mole of composition to obtain a ceramic raw material powder was mixed by a ball mill.

(4) Production of multilayer ceramic capacitor A multilayer ceramic capacitor was produced in the same manner as in Example 1 using the ceramic raw material powders of Test Examples 64-66 , and the same evaluation as in Example 1 was performed for each multilayer ceramic capacitor. The results are shown in Table 6.

Incidentally, Oite the test examples shown in Table 6, at least R-Mg-Si-O made of a crystalline complex oxide was present secondary phase particles mainly composed, R in its crystalline composite oxide, Mg , The molar ratio of Si is within the range of the triangle shown by hatching in FIG. 1, Mn is 0.2% by weight or more with respect to the crystalline composite oxide, and the molar ratio of R, Mg, Si is triangular. There were substantially no secondary phase particles outside the range.

According to the results shown in Table 6, the following were found.
In Test Examples 64 and 65 of this example, 0.98 ≦ Ti / (Zr + Ti + Hf) ≦ 1.0 is accompanied by a decrease in dielectric constant, as can be seen from a comparison with Test Example 66 not in this range. Therefore, the temperature characteristics can be further improved.

  In addition, this invention is not restrict | limited at all to the said Example, Unless it is contrary to the meaning of this invention, it is included by this invention.

  The present invention can be suitably used for a multilayer ceramic capacitor.

It is a phase diagram which shows the abundance ratio of R, Mg, Si in the secondary phase in the dielectric ceramic of this invention. It is sectional drawing which shows one Embodiment of the multilayer ceramic capacitor of this invention.

Explanation of symbols

1 Multilayer Ceramic Capacitor 2 Dielectric Ceramic Layer 3A, 3B Internal Electrode 4A, 4B External Electrode

Claims (6)

ABO ₃ (wherein the A site includes at least Ba of Ba, Ca, and Sr, and the B site represents a perovskite crystal including at least Ti of Ti, Zr, and Hf).
Rare earth element R (where R represents at least one of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) as an auxiliary component, Mg In a dielectric ceramic containing Si and Mn,
There are secondary phase particles mainly composed of a crystalline composite oxide composed of at least R, Mg, Si and Mn,
When the content molar ratio of R, Mg, and Si in the crystalline composite oxide is represented by x: y: z, x, y, and z are A (42,8,50) and B (8,42,50). , C (8,8,84) is in a range surrounded by a triangle whose apex is the vertex (however, the component on BC line and the component on AC line are included, but the component on AB line is not included) Dielectric ceramic. The content of the subcomponent with respect to 100 mol parts of the main component ABO ₃ is as follows: R is 4 to 20 mol parts, Mg is 2 to 15 mol parts, Si is 2 to 15 mol parts, and Mn is 0.5 to 5.0. The dielectric ceramic according to claim 1, wherein the dielectric ceramic is a molar part. 0.5 to 5.0 mol parts of M (including at least one of Cr, V, Fe, Co, Ni, Cu, Nb, Mo, and W) is included with respect to 100 mol parts of the main component ABO _3. The dielectric ceramic according to claim 1, wherein:   2. The relation of 0.98 ≦ Ti / (Zr + Ti + Hf) ≦ 1.00 is satisfied in terms of molar ratio when a part of Ti is substituted with Zr and Hf at the B site of the main component. The dielectric ceramic according to any one of claims 3 to 4. A step of preparing ABO ₃ (wherein the A site contains at least Ba of Ba, Ca, and Sr, and the B site represents a perovskite crystal containing at least Ti of Ti, Zr, and Hf);
A step of reacting at least a rare earth element compound and a silicon compound, and preparing a reactant A having crystallinity in a part thereof;
Reacting the reactant A having crystallinity with a magnesium compound to prepare a reactant B having crystallinity in a part thereof;
A step of preparing a ceramic raw material powder by mixing the ABO ₃ , the crystalline reactant B, and a manganese compound;
Firing the ceramic raw material powder;
A method for producing a dielectric ceramic, comprising:   Electrically connected to a plurality of laminated dielectric ceramic layers, a plurality of internal electrodes formed along a specific interface between the dielectric ceramic layers so as to obtain capacitance, and a specific one of the internal electrodes An external electrode connected to the multilayer ceramic capacitor, wherein the dielectric ceramic layer is formed of the dielectric ceramic according to any one of claims 1 to 4. Characteristic multilayer ceramic capacitor.

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