JP5127837B2 - Dielectric porcelain and multilayer ceramic capacitor - Google Patents

Description

  The present invention relates to a dielectric ceramic composed of crystal particles mainly composed of barium titanate and a multilayer ceramic capacitor using the dielectric ceramic as a dielectric layer.

  In recent years, there has been a high demand for downsizing of electronic components accompanying the increase in the density of electronic circuits, and the downsizing and increase in capacity of multilayer ceramic capacitors are rapidly progressing. Along with this, thinning of dielectric layers per layer in multilayer ceramic capacitors has progressed, and there is a demand for dielectric ceramics that can maintain the reliability as capacitors even when the thickness is reduced. In particular, very high reliability is required for dielectric ceramics in order to reduce the size and increase the capacity of a medium voltage capacitor used at a high rated voltage.

  Conventionally, a base metal can be used as a material constituting the internal electrode layer, and the temperature change of the capacitance satisfies the EIA standard X7R characteristic (−55 to 125 ° C., ΔC = ± 15% or less), The present applicant has proposed a dielectric ceramic disclosed in Patent Document 1.

  In this technology, a dielectric ceramic is formed by crystal grains mainly composed of two kinds of barium titanates having different calcium concentrations, and by adding magnesium, a rare earth element, manganese, and the like thereto, the relative dielectric constant is improved, Moreover, it was intended to improve the life characteristics of the insulation resistance (IR) in a high temperature load test. However, as miniaturization and capacity increase rapidly, further improvement in reliability is required.

  In addition, as a dielectric ceramic for a dielectric layer constituting a multilayer ceramic capacitor, the X7R characteristic of the EIA standard is satisfied as in Patent Document 1, and the life characteristic is improved in a high-temperature load test of insulation resistance. As dielectric ceramics intended to be used, those disclosed in Patent Documents 2 and 3 are further known.

  The dielectric ceramic disclosed in Patent Document 2 contains barium titanate, which is a main component of crystal particles constituting the dielectric ceramic, containing magnesium, rare earth elements, vanadium, and the like. (200) Life-time characteristics of dielectric breakdown voltage and insulation resistance in a high-temperature load test by forming a crystal structure (so-called core-shell structure) in which the diffraction line of the plane and the diffraction line of the (002) plane partially overlap to form a wide diffraction line This is an improvement.

Moreover, the dielectric ceramic disclosed in Patent Document 3 adjusts the valence of vanadium to be dissolved in barium titanate so as to be in a range close to tetravalent, thereby moving electrons existing in the crystal grains. High-temperature load test by suppressing excessive diffusion of vanadium and barium compound precipitation to barium titanate while forming a core-shell structure with a shell phase with an appropriate concentration gradient of vanadium. This is intended to improve life characteristics at
JP 2006-156450 A JP-A-8-124785 JP 2006-347799 A

  However, the dielectric ceramics disclosed in Patent Documents 1 to 3 described above have a high dielectric constant and a temperature change in relative permittivity of EIA standard X7R characteristics (−55 to 125 ° C., relative permittivity change rate is ± 15. %)), But there is a problem that the dielectric loss is large, and when the applied voltage is low, a high insulation resistance can be obtained, but when the applied voltage is increased, the insulation resistance greatly decreases. There was a problem of becoming.

  In addition, in a multilayer ceramic capacitor having these dielectric ceramics as a dielectric layer, when the dielectric layer is thinned due to a decrease in the insulation resistance of the dielectric ceramic, the life characteristics in the high temperature load test are improved. It was difficult to satisfy.

  Accordingly, an object of the present invention is to provide a high dielectric resistance and a small dielectric loss, a temperature change of the dielectric constant satisfies the X7R characteristic of the EIA standard, and a high insulation resistance can be obtained even when an applied voltage is low. It is an object of the present invention to provide a dielectric porcelain with a small decrease in insulation resistance when increasing. Furthermore, another object of the present invention is to provide a multilayer ceramic capacitor having such a dielectric ceramic as a dielectric layer and having excellent life characteristics in a high temperature load test.

The dielectric ceramic of the present invention is mainly composed of barium titanate, with respect to 100 moles of barium constituting the barium titanate, 0.05 to 0.3 moles of vanadium in terms of V ₂ O ₅ and MgO as MgO. 0 to 0.1 mol in terms of conversion, 0 to 0.5 mol in terms of manganese in terms of MnO, and one rare earth element (RE) selected from yttrium, dysprosium, holmium and erbium in an amount of 0.5 to 0.5 in terms of RE ₂ O ₃ Contains 1.5 moles and also contains calcium. Further, the dielectric ceramic according to the present invention comprises, as crystal particles, a first crystal group mainly composed of the barium titanate and having a calcium concentration of 0.2 atomic% or less, and the barium titanate. And a second crystal group composed of crystal grains having a calcium concentration of 0.4 atomic% or more.

  Furthermore, in the dielectric ceramic of the present invention, in the X-ray diffraction chart, the diffraction intensity of the (004) plane showing tetragonal barium titanate is higher than the diffraction intensity of the (004) plane showing cubic barium titanate. And the area of the crystal grains constituting the first crystal group seen on the polished surface of the dielectric ceramic is a, and the area of the crystal grains constituting the second crystal group is b, b / (a + b) is 0.4 to 0.7, and the average grain size of the crystal grains constituting the first crystal group and the crystal grains constituting the second crystal group is 0.21 to 0. .28 μm.

  The multilayer ceramic capacitor of the present invention is a laminate in which dielectric layers made of the above dielectric ceramics and internal electrode layers are alternately laminated, and is provided on both end faces of the laminate and connected to the internal electrode layers. And an external electrode.

  The rare earth element RE is based on the rare earth element in English (Rare earth). In the present invention, yttrium is included in the rare earth element.

  According to the dielectric ceramic of the present invention, the high dielectric constant and the dielectric loss are small, and the temperature change of the relative dielectric constant can satisfy the X7R characteristic of the EIA standard. In addition, a high insulation resistance can be obtained even when the applied voltage is low, and a decrease in the insulation resistance when the voltage is increased can be reduced (the voltage dependency of the insulation resistance is small).

  In the multilayer ceramic capacitor of the present invention, by applying the above-described dielectric ceramic as a dielectric layer, the dielectric constant has a high dielectric constant and low dielectric loss, and the temperature change of the relative dielectric constant satisfies the X7R characteristic of the EIA standard. In addition, even if the dielectric layer is made thin, high insulating properties can be secured, so that it has excellent life characteristics in a high temperature load test.

It is a cross-sectional schematic diagram which shows the microstructure of the dielectric material ceramic of this invention. (A) is a sample No. which is a dielectric ceramic of the present invention in Examples. 4 shows an X-ray diffraction chart of No. 4 and (b) shows a sample No. 4 which is a dielectric ceramic of a comparative example in Examples. 32 is an X-ray diffraction chart of 32. It is a cross-sectional schematic diagram which shows an example of the multilayer ceramic capacitor of this invention.

The dielectric ceramic of the present invention is mainly composed of barium titanate, with respect to 100 moles of barium constituting the barium titanate, 0.05 to 0.3 moles of vanadium in terms of V ₂ O ₅ and MgO as MgO. 0 to 0.1 mol in terms of conversion, 0 to 0.5 mol in terms of manganese in terms of MnO, and one rare earth element (RE) selected from yttrium, dysprosium, holmium and erbium in an amount of 0.5 to 0.5 in terms of RE ₂ O ₃ The first crystal group consisting of crystal particles containing 1.5 mol, further containing calcium, and mainly containing barium titanate as a crystal particle and having a calcium concentration of 0.2 atomic% or less, and mainly containing barium titanate A dielectric ceramic having a second crystal group composed of crystal grains having a calcium concentration of 0.4 atomic% or more, and an X-ray diffraction chip of the dielectric ceramic. The diffraction intensity of the (004) plane showing tetragonal barium titanate is greater than the diffraction intensity of the (004) plane showing cubic barium titanate and the surface of the dielectric ceramic is polished. B / (a + b) is 0.4 to 0.7, where a is the area of the crystal grains constituting the first crystal group and b is the area of the crystal grains constituting the second crystal group. In addition, the average grain size of the crystal grains constituting the first crystal group and the crystal grains constituting the second crystal group is 0.21 to 0.28 μm.

As a result, the relative permittivity is 3600 or more, the dielectric loss is 13% or less, the temperature change of the relative permittivity satisfies the X7R characteristic of the EIA standard, and the value of the DC voltage applied per unit thickness (1 μm) is 3. The insulation resistance when changing from 15 V / μm to 12.5 V / μm is 5 × 10 ⁸ Ω or more, and the insulation resistance at 3.15 V / μm and the insulation resistance at 12.5 V / μm A dielectric ceramic having a small difference of 0.2 × 10 ⁸ Ω or less can be obtained.

  FIG. 1 is a schematic cross-sectional view showing the microstructure of a dielectric ceramic according to the present invention. The dielectric ceramic of the present invention includes crystal particles 1a constituting the first crystal group mainly composed of barium titanate having a Ca concentration of 0.2 atomic% or less, and titanic acid having a Ca concentration of 0.4 atomic% or more. It is composed of crystal grains 1b constituting a second crystal group mainly composed of barium and a grain boundary phase 2.

  In the dielectric ceramic according to the present invention, the average particle size of the crystal particles 1 composed of the crystal particles 1a of the first crystal group and the crystal particles 1b of the second crystal group is 0.21 to 0.28 μm.

  That is, when the average particle diameter of the crystal particles 1 composed of the crystal particles 1a of the first crystal group and the crystal particles 1b of the second crystal group is smaller than 0.21 μm, the relative dielectric constant is lower than 3600. Although the relative dielectric constant increases when the average particle diameter of the crystal particles 1 consisting of the crystal particles 1a of the first crystal group and the crystal particles 1b of the second crystal group is larger than 0.28 μm, The dielectric loss may be larger than 13%.

  Here, the average particle size of the crystal particles 1 composed of the crystal particles 1a constituting the first crystal group and the crystal particles 1b constituting the second crystal group is determined by polishing (ion milling) the cross section of the dielectric ceramic. For the surface, capture the image projected by the transmission electron microscope into the computer, draw a diagonal line on the screen, image processing the outline of the crystal particles present on the diagonal line, find the area of each particle, The diameter when replaced with a circle having the same area is calculated and obtained from an average value of about 50 calculated crystal grains.

  As for the Ca concentration in the crystal particles, the elemental analysis was performed on about 30 crystal particles existing on the polished surface obtained by polishing the cross section of the dielectric ceramic using a transmission electron microscope provided with an element analysis device. Do. At this time, the spot size of the electron beam is 5 nm, and the location to be analyzed is in the range from the vicinity of the grain boundary of the crystal grain to the center position of the central portion, and is located at substantially equal intervals on a straight line drawn toward the center. The analysis value is an average value of 4 to 5 points analyzed between the vicinity of the grain boundary and the center, and Ba, Ti, Ca, V, Mg, rare earth elements detected from each measurement point of the crystal grains, and Taking the total amount of Mn as 100%, the Ca concentration at that time is determined. However, as for the crystal particles to be selected, the area of each particle is obtained from the contour by image processing, and the diameter when replaced with a circle having the same area is calculated. The diameter of the obtained crystal particles is ± 60 of the average particle diameter. Crystal grains in the range of%.

  The center part of the crystal grain means a range surrounded by a circle whose radius is 1/3 of the radius of the inscribed circle from the center of the inscribed circle of the crystal grain. The vicinity of the grain boundary refers to a region from the grain boundary of the crystal grain to 5 nm inside. For the inscribed circle of the crystal particle, an image projected by a transmission electron microscope is taken into a computer, and an inscribed circle is drawn on the crystal particle on the screen to determine the central portion of the crystal particle.

  In addition, as described above, the dielectric ceramic of the present invention has the crystal particles 1a constituting the first crystal group and the crystal particles 1b constituting the second crystal group as the crystal particles 1. The ratio is such that b / (a + b) is 0.4, where a is the area of the crystal grains 1a constituting the first crystal group and b is the area of the crystal grains 1b constituting the second crystal group. It is important to be ~ 0.7.

  That is, when b / (a + b), which is the ratio of the area of the crystal grains 1a constituting the first crystal group and the area of the crystal grains 1b constituting the second crystal group, is smaller than 0.4, The relative dielectric constant may be smaller than 3600. When b / (a + b) is larger than 0.7, the relative dielectric constant may be 3600 or more, but the dielectric loss may be larger than 13%.

  The area ratio of the crystal grains 1a constituting the first crystal group constituting the dielectric ceramic and the crystal grains 1b constituting the second crystal group is determined by using the area data used for obtaining the average grain size. calculate.

The dielectric ceramic of the present invention is mainly composed of barium titanate, with respect to 100 moles of barium constituting the barium titanate, 0.05 to 0.3 moles of vanadium in terms of V ₂ O ₅ and MgO as MgO. 0 to 0.1 mol in terms of conversion, 0 to 0.5 mol in terms of manganese in terms of MnO, and one rare earth element (RE) selected from yttrium, dysprosium, holmium and erbium in an amount of 0.5 to 0.5 in terms of RE ₂ O ₃ Contains 1.5 moles.

That is, when the vanadium content with respect to 100 mol of barium constituting barium titanate is less than 0.05 mol in terms of V ₂ O ₅ , the value of the DC voltage applied per unit thickness (1 μm) is 3. When the voltage is changed from 15 V / μm to 12.5 V / μm, the insulation resistance is greatly reduced. In such a multilayer ceramic capacitor having such a dielectric ceramic as a dielectric layer, the high temperature load life may be reduced.

When the vanadium content with respect to 100 mol of barium constituting barium titanate is more than 0.3 mol in terms of V ₂ O ₅ , the value of the DC voltage applied per unit thickness (1 μm) is 3.15 V / There is a possibility that the insulation resistance when both μm and 12.5 V / μm are set lower than 10 ⁸ Ω.

When one kind of rare earth element selected from yttrium, dysprosium, holmium and erbium is less than 0.5 mol in terms of RE ₂ O ₃ , the value of the DC voltage applied per unit thickness (1 μm) is 12 The insulation resistance at 1.5 V / μm is 1.5 × 10 ⁸ Ω or less, and the decrease in insulation resistance is larger than the value of insulation resistance when the DC voltage is 3.15 V / μm. There is a fear.

The rare earth element content selected from yttrium, dysprosium, holmium and erbium is more than 1.5 mol in terms of RE ₂ O ₃ , or the manganese content is more than 0.5 mol in terms of MnO. In some cases, the relative dielectric constant may be lower than 3600.

  Furthermore, when the magnesium content is more than 0.1 mol in terms of MgO, the temperature change of the dielectric constant may not satisfy the X7R characteristic of the EIA standard, and per unit thickness (1 μm). When the value of the DC voltage to be applied is 3.15 V / μm and 12.5 V / μm, the insulation resistance decreases greatly, and the life characteristics in the high temperature load test may be deteriorated.

In contrast, the dielectric ceramic of the present invention can have a relative dielectric constant of 3600 or more and a dielectric loss of 13% or less as described above, and the temperature change of the dielectric constant satisfies the X7R characteristic of EIA standard. Furthermore, when the value of the DC voltage applied per unit thickness (1 μm) is 3.15 V / μm and 12.5 V / μm, the insulation resistance is 10 ⁸ Ω or more, and the insulation resistance is reduced. Almost no dielectric ceramic can be obtained.

In the dielectric ceramic of the present invention, barium titanate is the main component, and with respect to 100 moles of barium constituting the barium titanate, vanadium is 0.05 to 0.3 mole in terms of V ₂ O ₅ and manganese is MnO. 0.5 mol or less in terms of conversion, when a rare earth element (RE) selected from yttrium, dysprosium, holmium and erbium is included in an amount of 0.5 to 1.5 mol in terms of RE ₂ O ₃ , magnesium is 0 mol in terms of MgO. It is desirable to be.

  With such a composition of the dielectric porcelain, the high dielectric constant and the dielectric loss are small, the temperature change of the relative dielectric constant can satisfy the X7R characteristic of the EIA standard, and even when the applied voltage is low A dielectric ceramic having a higher insulation resistance and a smaller voltage dependency of the insulation resistance can be obtained. More specifically, high insulation in which the applied DC voltage tends to increase the insulation resistance (positive change) between 3.15 V / μm and 12.5 V / μm per unit thickness (1 μm) of the dielectric layer. And a dielectric ceramic with low dielectric loss can be obtained.

Further, in the dielectric ceramic according to the present invention, barium titanate is the main component, and with respect to 100 moles of barium constituting the barium titanate, 0.05 to 0.3 mole of vanadium in terms of V ₂ O ₅ , yttrium. , Dysprosium, holmium, and erbium containing a rare earth element in an amount of 0.5 to 1.5 mol in terms of RE ₂ O ₃ , magnesium is 0 mol in terms of MgO and manganese is 0 mol in terms of MnO It is desirable.

  By setting it as the said composition, while being able to obtain the dielectric ceramic with small voltage dependency of an insulation resistance, a dielectric loss can be reduced further. Here, 0 mol of magnesium in terms of MgO or 0 mol of manganese in terms of MnO means that magnesium or manganese is not substantially contained. For example, each component is detected in ICP analysis of a dielectric ceramic. The case where it is below the limit (0.5 μg / g or less).

  In the case where yttrium, dysprosium, holmium, and erbium are included among the rare earth elements, a heterogeneous phase is hardly generated when solid solution is formed in barium titanate, and high insulation can be obtained. Yttrium is more preferable because the relative dielectric constant of the dielectric ceramic can be increased.

In the present invention, in the dielectric ceramic according to the present invention described above, it is desirable to further contain terbium in a range of 0.3 mol or less in terms of Tb ₄ O ₇ with respect to 100 mol of barium constituting barium titanate. . As a result, the insulation resistance of the dielectric ceramic can be increased, and the life characteristics in the high temperature load test can be further improved when the above-mentioned dielectric ceramic is applied to the dielectric layer of the multilayer ceramic capacitor. If the terbium content is more than 0.3 mol in terms of Tb ₄ O ₇ , the dielectric constant of the dielectric ceramic may be lowered. Moreover, in order to acquire the sufficient effect by containing terbium, it is good to contain 0.05 mol or more.

In the present invention, in the dielectric ceramic of the present invention described above, ytterbium is further contained in a range of 0.3 to 0.7 mol in terms of Yb ₂ O ₃ with respect to 100 mol of barium constituting barium titanate. It is desirable to do. As a result, the insulation resistance at 125 ° C. required for X7R characteristics can be increased to 2 × 10 ⁷ Ω or more, and the change in relative dielectric constant can be suppressed even when the firing temperature changes (for example, about 20 ° C.). Therefore, even if a large firing furnace having a variation in furnace temperature is used, the variation in relative dielectric constant can be reduced and the yield can be improved. When the amount is more than 0.7 mol, the life characteristics in the high temperature load test may be deteriorated.

  Furthermore, in the dielectric ceramic of the present invention, in the X-ray diffraction chart, the diffraction intensity of the (004) plane indicating tetragonal barium titanate is the diffraction intensity of the (004) plane indicating cubic barium titanate. Greater than.

  Here, the crystal structure of the dielectric ceramic according to the present invention will be described in more detail. The dielectric ceramic according to the present invention is a single-phase crystal almost exhibiting a tetragonal system even when vanadium is dissolved in crystal grains. Occupied by a phase.

  2A shows a sample No. 1 which is a dielectric ceramic according to the present invention in Tables 1 to 3 of Examples described later. 4 shows an X-ray diffraction chart of No. 4, and FIG. 32 is an X-ray diffraction chart of 32.

  Here, in the conventional dielectric ceramics described in Patent Document 2 and Patent Document 3, the crystal structure is a core-shell structure, which corresponds to the X-ray diffraction chart of FIG.

  That is, in a dielectric ceramic composed of crystal grains having a barium titanate as a main component and having a core-shell structure, barium titanate appearing between the (004) plane and the (400) plane showing the tetragonal system of barium titanate. The diffraction intensity of the (004) plane (the (040) plane and (400) plane overlap) of the cubic system is greater than the diffraction intensity of the (004) plane representing the tetragonal system of barium titanate. It has become.

  In addition, dielectric porcelain composed of crystal grains having a core-shell structure has a higher proportion of cubic crystal phases than tetragonal crystal phases, as seen from the X-ray diffraction chart. The sex becomes smaller. Therefore, in the X-ray diffraction chart, the (400) plane diffraction lines are shifted to the low angle side and the (004) plane diffraction lines are shifted to the high angle side, so that both diffraction lines overlap each other at least partially. It becomes a wide diffraction line.

  Such dielectric porcelain is usually formed by forming a powder containing barium titanate as a main component and adding an oxide powder such as magnesium or a rare earth element, followed by reduction firing. is there. In this case, since the crystal particles having a core-shell structure have a small amount of solid solution of components such as magnesium and rare earth elements in the core portion, they are in a state containing many defects such as oxygen vacancies inside the crystal particles. For this reason, when a DC voltage is applied, oxygen vacancies and the like are likely to be carriers that carry electric charges inside the crystal grains, and it is considered that the insulation of the dielectric ceramic is lowered.

  In contrast, the dielectric ceramic of the present invention, as illustrated in FIG. 2 (a), has a (004) plane diffraction intensity indicating the tetragonal system of barium titanate in the X-ray diffraction chart of the dielectric ceramic. However, the diffraction intensity of the (004) plane showing the cubic system of barium titanate is preferably larger.

  That is, as shown in FIG. 2A, the dielectric ceramic of the present invention has a (004) plane (around 2θ = 100 °) and a (400) plane (2θ = 101) indicating the tetragonal system of barium titanate. The X-ray diffraction peak at around (°) appears clearly, and shows the cubic system of barium titanate appearing between these (004) plane and (400) plane showing the tetragonal system of barium titanate (004). ) Plane (the (040) plane and (400) plane overlap) is smaller than the diffraction intensity of the (004) plane showing the tetragonal system of barium titanate.

  In the dielectric ceramic of the present invention, when the diffraction intensity of the (004) plane showing the tetragonal system of barium titanate is Ixt and the diffraction intensity of the (004) plane showing the cubic system of barium titanate is Ixc, The Ixt / Ixc ratio is preferably 1.4 or more. When the Ixt / Ixc ratio is 1.4 or more, the ratio of the tetragonal crystal phase increases, the relative dielectric constant increases, the change rate of the insulation resistance can be further reduced, and the life characteristics in the high temperature load test are improved. It becomes possible.

  Such a dielectric ceramic of the present invention has a substantially uniform crystal phase of tetragonal system even if it contains vanadium. Therefore, such crystal particles are solidly composed of vanadium and other additive components throughout. It is thought that it is melted. For this reason, the generation of defects such as oxygen vacancies is suppressed inside the crystal grains and the number of carriers that carry charges is small, so it is considered possible to suppress the decrease in the insulation of the dielectric ceramic when a DC voltage is applied. .

  In other words, the oxygen vacancies in the dielectric ceramic according to the present invention are electrically neutralized by the vanadium atoms substituted and dissolved in the titanium sites being electrically coupled with the oxygen vacancies to form defect pairs. For this reason, the contribution to conduction by the application of an electric field is reduced, and even if oxygen vacancies are present, the mobility is lowered, so that it is considered that the reduction of the insulation resistance in the high temperature load test is hindered.

  The dielectric ceramic according to the present invention may contain other components in addition to the above-described components as long as desired dielectric characteristics can be maintained. For example, a glass component as an auxiliary agent for enhancing sinterability. And other additive components can be contained in the dielectric ceramic in a proportion of 0.5 to 2% by mass.

Next, a method for manufacturing the dielectric ceramic according to the present invention will be described. However, the manufacturing method described below is an example, and the method is not limited to this method. First, barium titanate powder (hereinafter referred to as BT powder) having a purity of 99% or more as a raw material powder, powder in which calcium is dissolved in barium titanate (hereinafter referred to as BCT powder), and V ₂ O ₅ powder and MgO powder, and also Y ₂ O ₃ powder, Dy ₂ O ₃ powder, Ho ₂ O ₃ powder and Er ₂ O ₃ powder, oxide powder of at least one rare earth element and MnCO ₃ powder Prepare. When the dielectric ceramic contains terbium as a rare earth element, it is preferable to use Tb ₄ O ₇ powder as an oxide of the rare earth element. In addition, when ytterbium is contained as the third rare earth element in the dielectric ceramic, it is preferable to use Yb ₂ O ₃ powder as the oxide of the rare earth element.

The BCT powder is a solid solution mainly composed of barium titanate in which a part of the A site is substituted with Ca, and is represented by (Ba _1-x Ca _x ) TiO ₃ . The amount of Ca substitution in the A site is preferably X = 0.01 to 0.2. If the amount of Ca substitution is within this range, a crystal structure in which grain growth is suppressed can be formed by the coexistence structure with the first crystal grains 1a. Thus, when used as a capacitor, excellent temperature characteristics can be obtained in the operating temperature range. Note that Ca contained in the second crystal particles 1b is solid-dissolved in a state of being dispersed in the second crystal particles 1b.

  Moreover, the average particle diameter of BT powder and BCT powder is 0.13-0.17 micrometer, Especially 0.15-0.17 micrometer is preferable. When the average particle size of the BT powder and the BCT powder is 0.13 μm or more, the first crystal particle 1a and the second crystal particle 1b become highly crystalline and can suppress grain growth during sintering. There is an advantage that the dielectric loss can be reduced as the relative dielectric constant is improved.

  On the other hand, when the average particle size of the BT powder and the BCT powder is 0.17 μm or less, additives such as magnesium, rare earth elements, and manganese are dissolved in the first crystal particles 1a and the second crystal particles 1b. It becomes easy to make. Further, as will be described later, the ratio of grain growth from the BT powder and the BCT powder to the crystal particles 1a constituting the first crystal group and the crystal particles 1b constituting the second crystal group, respectively, before and after firing is predetermined. There is also an advantage that it can be increased to the range of.

Y ₂ O ₃ powder, Dy ₂ O ₃ powder, Ho ₂ O ₃ powder and Er ₂ O ₃ powder as additives, oxide powder of at least one rare earth element, Tb ₄ O ₇ powder, Yb ₂ O ₃ As for the powder, V ₂ O ₅ powder, MgO powder, and MnCO ₃ powder, it is preferable to use those having an average particle diameter equivalent to or less than that of dielectric powder such as BT powder and BCT powder.

Subsequently, 0.05 to 0.3 mol of V ₂ O ₅ powder, 0 to 0.1 mol of MgO powder, and MnCO ₃ powder with respect to 100 mol of barium constituting the BT powder and BCT powder. 0 to 0.5 mol, a rare earth element (RE) selected from Y ₂ O ₃ powder, Dy ₂ O ₃ powder, Ho ₂ O ₃ powder and Er ₂ O ₃ powder is 0.5 to 0.5 in terms of RE ₂ O _3. in proportions of 1.5 mole, further, if necessary with the addition of _Tb 4 _{O 7} powder 0 to 0.3 mol, the _Yb 2 _{O 3} powder at a ratio of 0.3 to 0.7 molar A molded body is produced. Next, the molded body is degreased and then fired in a reducing atmosphere.

  In the production of the dielectric ceramic of the present invention, glass powder may be added as a sintering aid so long as the desired dielectric properties can be maintained, and the addition amount is the main raw material powder. When the total amount of BT powder and BCT powder is 100 parts by mass, 0.5 to 2 parts by mass is preferable.

  When a sintering aid such as glass powder is used, the firing temperature is preferably 1050 to 1135 ° C. for the purpose of controlling the solid solution of the additive in the BT powder and the BCT powder and the grain growth of the crystal particles. . On the other hand, without using a sintering aid such as glass powder, sintering at a temperature lower than 1050 ° C. is possible in the case of pressure firing such as a hot press method.

  In order to obtain the dielectric ceramic according to the present invention, fine BT powder and BCT powder are used, a predetermined amount of the above-mentioned additives are added thereto, and BT powder and BCT containing various additives at the above-mentioned firing temperature. It is preferable to fire the powder so that the average particle size of the powder increases to about 1.4 to 2.1 times after firing. By firing so that the average particle size of the crystal particles after firing is 1.4 to 2.1 times the average particle size of the BT powder and BCT powder, the first crystal particles 1a and the second crystal particles As for 1b, vanadium and other additive components are dissolved in the whole, and as a result, the generation of defects such as oxygen vacancies is suppressed inside the crystal particles, and it is considered that a state is formed in which there are few carriers that carry charge .

  In the present invention, after firing, heat treatment is performed again in a nitrogen atmosphere. This heat treatment is performed to reoxidize the dielectric ceramic reduced in firing in a reducing atmosphere and recover the insulation resistance reduced and reduced during firing. The heat treatment temperature is preferably 900 to 1100 ° C. for the purpose of increasing the amount of reoxidation while suppressing further grain growth of the crystal grains 1a constituting the first crystal group and the crystal grains 1b constituting the second crystal group. .

  FIG. 3 is a schematic cross-sectional view showing an example of the multilayer ceramic capacitor of the present invention. External electrodes 4 are provided at both ends of the capacitor body 10. The capacitor body 10 is composed of a laminated body 10A in which dielectric layers 5 and internal electrode layers 7 are alternately laminated. The dielectric layer 5 is preferably formed by the dielectric ceramic of the present invention described above.

  In FIG. 3, the laminated state of the dielectric layer 5 and the internal electrode layer 7 is shown in a simplified manner. However, in the multilayer ceramic capacitor of the present invention, the dielectric layer 5 and the internal electrode layer 7 are several hundred layers. A laminated body 10 </ b> A is formed.

  According to the multilayer ceramic capacitor of the present invention, by applying the above dielectric ceramic as the dielectric layer 5, the dielectric constant is low and the dielectric constant is high, and the temperature change of the relative dielectric constant is EIA standard. X7R characteristics are satisfied, and even if the dielectric layer 5 is thinned, high insulation can be ensured, and a multilayer ceramic capacitor having excellent life characteristics in a high temperature load test can be obtained. According to the dielectric ceramic of the present invention, since a high dielectric constant and a low dielectric loss can be realized, for example, energy loss when used as a bypass capacitor can be reduced, thereby functioning as a capacitor capable of inputting and outputting a high-capacity charge. There is an advantage that can be increased.

  Here, the thickness of the dielectric layer 5 is preferably 3 μm or less, and particularly preferably 2.5 μm or less in order to reduce the size and capacity of the multilayer ceramic capacitor. The thickness of the dielectric layer 5 is desirably 1 μm or more in order to stabilize the capacitance variation and capacitance temperature characteristics.

  The internal electrode layer 7 is preferably a base metal such as nickel (Ni) or copper (Cu) in that the manufacturing cost can be suppressed even when the number of layers is increased, and in particular, simultaneous firing with the dielectric layer 15 in the present invention can be achieved. In this respect, nickel (Ni) is more desirable.

  The external electrode 4 is formed by baking, for example, Cu or an alloy paste of Cu and Ni.

  Next, an example of a method for manufacturing a multilayer ceramic capacitor will be described. A ceramic slurry is prepared by adding a dedicated organic vehicle to the raw material powder, and then a ceramic green sheet is formed from the ceramic slurry using a sheet forming method such as a doctor blade method or a die coater method. In this case, the thickness of the ceramic green sheet is preferably 1 to 4 μm from the viewpoint of reducing the thickness of the dielectric layer 5 to increase the capacity and maintaining high insulation.

  A rectangular internal electrode pattern is printed on the main surface of the obtained ceramic green sheet. Ni, Cu, or an alloy powder thereof is suitable for the conductor paste that forms the internal electrode pattern.

  Stack a desired number of ceramic green sheets with internal electrode patterns, and stack a plurality of ceramic green sheets without internal electrode patterns on the top and bottom so that the upper and lower layers are the same number. To do. In this case, the internal electrode pattern in the sheet laminate is shifted by a half pattern in the longitudinal direction.

  Next, the sheet laminate is cut into a lattice shape to form a capacitor body molded body so that the end of the internal electrode pattern is exposed. By such a laminating method, the internal electrode pattern can be formed so as to be alternately exposed on the end surface of the cut capacitor body molded body.

  After degreasing the obtained capacitor body molded body, the capacitor body is fabricated by performing heat treatment under the same firing conditions and weak reducing atmosphere as the above dielectric ceramic.

  Finally, the external electrode paste is applied to both ends of the capacitor body and baked to form the external electrode 4. Further, a plating film may be formed on the surface of the external electrode 4 in order to improve mountability.

  EXAMPLES Hereinafter, although an Example is given and the dielectric material ceramic and multilayer ceramic capacitor of this invention are demonstrated in detail, this invention is not limited to a following example.

[Example 1]
<Production of multilayer ceramic capacitor>
First, as the raw material powder, BT powder, BCT powder (composition _{(Ba 1-x Ca x)} TiO 3, X = 0.05), MgO _powder, Y 2 _{O 3} powder, _Dy 2 _{O 3} powder, _Ho 2 O ₃ powder, Er ₂ O ₃ powder, Tb ₄ O ₇ powder (second rare earth element), MnCO ₃ powder and V ₂ O ₅ powder were prepared, and these various powders were mixed in the proportions shown in Table 1. These raw material powders having a purity of 99.9% were used.

The average particle size of the BT powder and BCT powder used is shown in Table 1. MgO powder, Y ₂ O ₃ powder, Dy ₂ O ₃ powder, Ho ₂ O ₃ powder, Er ₂ O ₃ powder, Tb ₄ O ₇ powder, MnCO ₃ powder and V ₂ O ₅ powder have an average particle size of 0.1 μm. The thing of was used. The Ba / Ti ratio of the BT powder was 1. As the sintering aid, glass powder having a composition of SiO ₂ = 55, BaO = 20, CaO = 15, and Li ₂ O = 10 (mol%) was used. The addition amount of the glass powder was 1 part by mass with respect to 100 parts by mass of the BT powder.

  Next, these raw material powders were wet mixed by adding a mixed solvent of toluene and alcohol as a solvent using zirconia balls having a diameter of 5 mm. A polyvinyl butyral resin and a mixed solvent of toluene and alcohol are added to the wet-mixed powder, and a ceramic slurry is prepared by wet-mixing using a zirconia ball having the same diameter of 5 mm. A ceramic green sheet having a thickness of 2.5 μm is prepared by a doctor blade method. Produced.

  A plurality of rectangular internal electrode patterns mainly containing Ni were formed on the upper surface of the ceramic green sheet. The conductor paste used for the internal electrode pattern was Ni powder having an average particle size of 0.3 μm, and 30 parts by mass of BT powder used for a green sheet as a co-material with respect to 100 parts by mass of Ni powder.

Next, 360 ceramic green sheets on which internal electrode patterns were printed were laminated, and 20 ceramic green sheets on which the internal electrode patterns were not printed were laminated on the upper and lower surfaces, respectively, using a press machine at a temperature of 60 ° C. and pressure Lamination was performed under the conditions of 10 ⁷ Pa and time 10 minutes, and cut into predetermined dimensions to form a laminated molded body.

The obtained laminated molded body was heated to 300 ° C. in the air at a temperature rising rate of 10 ° C./h, and the binder removal treatment was performed at the temperature. Subsequently, after heating to 500 degreeC with the same temperature increase rate, the temperature increase rate from 500 degreeC was 300 degreeC / h, and it baked at 1115-1160 degreeC for 2 hours in hydrogen-nitrogen. Next, after cooling to 1000 ° C. at a rate of temperature decrease of 300 ° C./h, heat treatment (reoxidation treatment) is performed at 1000 ° C. for 4 hours in a nitrogen atmosphere, and cooling is performed at a rate of temperature decrease of 300 ° C./h. Produced. The size of this capacitor body was 0.95 × 0.48 × 0.48 mm ³ , the thickness of the dielectric layer was 2 μm, and the area of one internal electrode layer was 0.3 mm ² .

Next, the fired capacitor body was barrel-polished, and then an external electrode paste containing Cu powder and glass was applied to both ends of the capacitor body and baked at 850 ° C. to form external electrodes. Thereafter, using an electrolytic barrel machine, Ni plating and Sn plating were sequentially performed on the surface of the external electrode to produce a multilayer ceramic capacitor.
<Evaluation>
The obtained multilayer ceramic capacitor was evaluated as follows. In each evaluation, the number of samples was 10 and the average value was obtained.
(1) Relative permittivity The capacitance is measured under the measurement conditions of a temperature of 25 ° C., a frequency of 1.0 kHz, and a measurement voltage of 1 Vrms. From the obtained capacitance, the thickness of the dielectric layer, the total area of the internal electrode layer, and the vacuum It was calculated based on the dielectric constant of
(2) Dielectric loss Measured under the same conditions as the capacitance.
(3) Temperature characteristics of relative permittivity The capacitance was determined by measuring the capacitance in the temperature range of −55 to 125 ° C.
(4) Insulation resistance Evaluation was made under the conditions of a DC voltage of 3.15 V / μm and 12.5 V / μm. The insulation resistance was read 1 minute after application of a DC voltage. (5) High-temperature load test The test was performed at a temperature of 170 ° C. under an applied voltage of 30 V (15 V / μm). The number of samples in the high temperature load test was 20 samples.
(6) Average particle diameter of crystal grains comprising the crystal grains constituting the first crystal group and the crystal grains constituting the second crystal group Polishing to a state where the cross section of the dielectric ceramic can be observed with a transmission electron microscope For the polished surface (ion milling), an image displayed by a transmission electron microscope is taken into a computer, a diagonal line is drawn on the screen, and the contours of crystal particles existing on the diagonal line are image-processed. The diameter when the area was replaced with a circle having the same area was calculated, and the average value of about 50 calculated crystal grains was determined. Further, the rate of grain growth from the dielectric powder was evaluated as {(average particle diameter of crystal particles) / (average particle diameter of dielectric powder)} × 100 (%).
(7) Measurement of b / (a + b) Elemental analysis was performed on approximately 30 crystal particles present on the polished surface of the dielectric layer obtained by polishing the cross section in the stacking direction of the multilayer ceramic capacitor with respect to the Ca concentration in the crystal particles. Elemental analysis was performed using a transmission electron microscope equipped with an instrument. At this time, the spot size of the electron beam was 5 nm, and the locations to be analyzed were points located at substantially equal intervals on a straight line drawn from the vicinity of the grain boundary of the crystal grains toward the center. The area to be analyzed is a range from the vicinity of the grain boundary of the crystal grain to the center position of the central part, and the points are located at almost equal intervals on the straight line drawn toward the center, and the analysis values are the vicinity of the grain boundary and the center. The average value of the values analyzed between 4 and 5 points is taken as 100%, and the total amount of Ba, Ti, Ca, V, Mg, rare earth elements and Mn detected from each measurement point of the crystal particles is taken as 100%. The concentration of Ca was determined.

  In such an analysis, a crystal particle having a calcium concentration of 0.2 atomic% or less is referred to as a “crystal particle constituting the first crystal group”, and a crystal particle having a calcium concentration of 0.4 atomic% or more is used. “Crystal grains constituting the second crystal group”. Further, in this case, the crystal particles to be selected are obtained by calculating the area of each particle by image processing from the outline, and calculating the diameter when replaced with a circle having the same area, and thus the crystal particle for which the diameter has been obtained Crystal grains having a diameter of ± 60% of the average particle diameter.

  In this measurement, the central part of the crystal grain is in the range of 1/3 of the radius from the center of the inscribed circle of the crystal grain, while the vicinity of the grain boundary of the crystal grain is 5 nm inside from the grain boundary of the crystal grain. The area. The inscribed circle of the crystal grains was drawn on the screen of a computer from the image projected by the transmission electron microscope, and the center of the crystal grains was determined from the image on the screen.

Area ratio of crystal grains constituting the first crystal group and the second crystal group in the dielectric ceramic, b / (a + b) (where a is the crystal grain 1a constituting the first crystal group (B represents the area of the crystal particles 1b constituting the second crystal group) was calculated from the area data obtained by calculating the average particle diameter of the crystal particles 1a and 1b for the above-mentioned 50 particles.
(8) Composition analysis of sample The composition analysis of the sample which is the obtained sintered body was performed by ICP analysis or atomic absorption analysis. In this case, the obtained dielectric porcelain mixed with boric acid and sodium carbonate and dissolved in hydrochloric acid is first subjected to qualitative analysis of the elements contained in the dielectric porcelain by atomic absorption spectrometry, and then specified. The diluted standard solution for each element was used as a standard sample and quantified by ICP emission spectroscopic analysis. Further, the amount of oxygen was determined using the valence of each element as the valence shown in the periodic table.

表１〜３の結果から明らかなように、本発明の試料Ｎｏ．１−４〜７、９〜１３、１５、１６、１９〜２２、２５、２６、２８〜３１および３３〜３５では、比誘電率が３６００以上、誘電損失１３％以下、比誘電率の温度変化がＥＩＡ規格のＸ７Ｒ特性を満足するものとなり、単位厚み（１μｍ）当たりに印加する直流電圧の値を３．１５Ｖ／μｍおよび１２．５Ｖ／μｍとしたときの絶縁抵抗の低下が小さく、絶縁抵抗の電圧依存性のさらに小さい誘電体磁器を得ることができた。表３では、仮数部と指数部の間にＥを入れる指数表記で示しており、例えば「５．２Ｅ＋０８」とは５．２×１０^８を意味している（後述する表６も同じである）。また、高温負荷試験での寿命特性が１７０℃、１５Ｖ／μｍの条件で６０時間以上であった。Table 1 shows the preparation composition and the firing temperature, Table 2 shows the composition of each element in the sintered body in terms of oxide, and Table 3 shows the results of the characteristics. Here, in the ICP analysis of the dielectric ceramic, the case where each component was below the detection limit (0.5 μg / g or less) was defined as 0 mol.

As is apparent from the results in Tables 1 to 3, the sample No. In 1-4-7, 9-13, 15, 16, 19-22, 25, 26, 28-31 and 33-35, the relative permittivity is 3600 or more, the dielectric loss is 13% or less, and the temperature change of the relative permittivity Satisfies the X7R characteristics of the EIA standard, and when the DC voltage applied per unit thickness (1 μm) is 3.15 V / μm and 12.5 V / μm, the decrease in insulation resistance is small, and the insulation resistance It was possible to obtain a dielectric ceramic having a smaller voltage dependency. Table 3 shows an exponent notation in which E is inserted between the mantissa part and the exponent part. For example, “5.2E + 08” means 5.2 × 10 ⁸ (the same applies to Table 6 described later). ). Moreover, the lifetime characteristic in the high temperature load test was 60 hours or more under the conditions of 170 ° C. and 15 V / μm.

Further, barium titanate is the main component, and with respect to 100 moles of barium constituting the barium titanate, vanadium is 0.05 to 0.3 mole in terms of V ₂ O ₅ and manganese is 0 to 0.00 in terms of MnO. 5 mol, a rare earth element selected from yttrium, dysprosium, holmium and erbium is contained in an amount of 0.5 to 1.5 mol in terms of RE ₂ O ₃ , ytterbium in terms of Yb ₂ O ₃ and 0 mol in terms of magnesium. Sample no. In 1-4-7, 9, 10, 15, 16, 19-22, 25, 26, 28-31 and 33-35, the dielectric loss can be reduced to 12.7% or less, and the applied DC voltage is dielectric A highly insulating dielectric ceramic exhibiting a tendency (positive change) in the insulation resistance to increase between 3.15 V / μm and 12.5 V / μm per unit thickness (1 μm) of the body layer can be obtained. It was.

Further, the main component is barium titanate, and the vanadium is selected from 0.05 to 0.3 mol in terms of V ₂ O ₅ and yttrium, dysprosium, holmium and erbium with respect to 100 mol of barium constituting the barium titanate. The rare earth element contained is 0.5 to 1.5 mol in terms of RE ₂ O ₃ , ytterbium is 0 mol in terms of Yb ₂ O ₃ , magnesium is 0 mol in terms of MgO, and manganese is 0 mol in terms of MnO. Sample No. In 1-4-7, 9, 10, 15, 16, 19-22, 25, 26, 28-31 and 33-35, the dielectric loss could be further reduced.

Further, vanadium, rare earth element, magnesium and manganese are contained in an amount specified in the present invention with respect to 100 mol of barium constituting barium titanate, and 0 mol in terms of Yb ₂ O ₃ and terbium in Tb ₄ O. Sample No. ₇ containing 0.05 to 0.3 mol in terms of ₇ In 1-4-7, 9-13, 15, 16, 19-22, 25, 26, 29-30 and 33-35, sample No. which does not contain terbium. The insulation resistance of the dielectric ceramic can be increased as compared with 28, and when the above dielectric ceramic is applied to the dielectric layer of the multilayer ceramic capacitor, the life characteristics in the high temperature load test are further improved.

On the other hand, in a sample outside the scope of the present invention, the relative permittivity is lower than 3600, the dielectric loss is greater than 13%, the temperature change of the relative permittivity does not satisfy the X7R characteristic of the EIA standard, or When the value of the DC voltage applied per unit thickness (1 μm) was measured as 12.5 V / μm, the insulation resistance was lower than 10 ⁸ Ω or the life characteristics of the high temperature load test were 8 hours or less.
[Example 2]
A sample was prepared and evaluated in the same manner as in Example 1 by adding 0.35 mol of ytterbium in terms of Yb ₂ O ₃ to each composition of the sample of the present invention shown in Example 1 (Sample No.). .2-1 to 24).

In addition, sample No. With respect to 1-6, 0 to 0.9 mol of ytterbium was added in terms of Yb ₂ O ₃ , the sample was prepared and evaluated in the same manner as in Example 1 at a firing temperature of 1135 ° C. (Sample No. 2- 25-31).

表４〜６の結果から明らかなように、実施例１に示した本発明の試料である各組成に、さらにイッテルビウムをＹｂ_２Ｏ_３換算で０．３５モル含有させた試料Ｎｏ．２−１〜２４は、いずれの組成についてもイッテルビウムを含有しない組成の試料と同等の特性が得られた。The composition and firing temperature are shown in Table 4, the composition of each element in the sintered body in terms of oxide is shown in Table 5, and the results of the characteristics are shown in Table 6, respectively.

As is apparent from the results of Tables 4 to 6, sample No. 1 was obtained by further adding 0.35 mol of ytterbium in terms of Yb ₂ O ₃ to each of the compositions of the present invention shown in Example 1. In 2-1 to 24, the same characteristics as those of the sample having a composition not containing ytterbium were obtained for any composition.

In addition, sample No. Sample No. 1 prepared by adding 0 to 0.9 mol of ytterbium in terms of Yb ₂ O ₃ and firing at 1135 ° C. with respect to 1-6. Sample Nos. 2-25 to 31 which contain 0.3 to 0.7 mol of ytterbium in terms of Yb ₂ O ₃ . 2-27 to 30 are sample Nos. Compared with the samples (sample Nos. 2-25 and 26) in which the difference in relative dielectric constant from 1-6 is as small as 100 or less and the ytterbium content is 0.2 mol or less, The change was small. Sample No. 1 containing 0.9 mol of ytterbium in terms of Yb ₂ O ₃ was used. Compared with 2-31, the life characteristics in the high temperature load test were as high as 45 hours or more. A sample containing 0.3 to 0.7 mol of ytterbium in terms of Yb ₂ O ₃ had an insulation resistance of at least 2.1 × 10 ⁷ Ω at 125 ° C.

Claims (7)

Mainly composed of barium titanate,
With respect to 100 moles of barium constituting the barium titanate,
0.05-0.3 mol of vanadium in terms of V ₂ O ₅ ,
0 to 0.1 mol of magnesium in terms of MgO,
0 to 0.5 mol of manganese in terms of MnO,
0.5 to 1.5 mol of one rare earth element (RE) selected from yttrium, dysprosium, holmium and erbium in terms of RE ₂ O ₃ ,
In addition to containing calcium,
As crystal particles,
A first crystal group consisting mainly of the barium titanate and having a calcium concentration of 0.2 atomic% or less;
A dielectric ceramic having a second crystal group mainly composed of the barium titanate and having a calcium concentration of 0.4 atomic% or more;
In the X-ray diffraction chart of the dielectric ceramic, the diffraction intensity of the (004) plane showing tetragonal barium titanate is larger than the diffraction intensity of the (004) plane showing cubic barium titanate,
When the area of the crystal grains constituting the first crystal group and the area of the crystal grains constituting the second crystal group seen on the polished surface of the dielectric ceramic is b and b / ( a + b) is 0.4 to 0.7,
The dielectric ceramic according to claim 1, wherein an average particle diameter of crystal grains constituting the first crystal group and crystal grains constituting the second crystal group is 0.21 to 0.28 μm.   The dielectric ceramic according to claim 1, wherein the magnesium is 0 mol in terms of MgO.   The dielectric ceramic according to claim 2, wherein the manganese is 0 mol in terms of MnO. The dielectric ceramic according to any one of claims 1 to 3, further comprising 0.3 mol or less of terbium in terms of Tb ₄ O ₇ with respect to 100 mol of barium constituting the barium titanate. . The ytterbium is further contained in an amount of 0.3 to 0.7 mol in terms of Yb ₂ O ₃ with respect to 100 mol of barium constituting the barium titanate, according to any one of claims 1 to 4. Dielectric porcelain.   When the diffraction intensity of the (004) plane showing the tetragonal barium titanate is Ixt and the diffraction intensity of the (004) plane showing the cubic barium titanate is Ixc, the Ixt / Ixc ratio is 1. The dielectric ceramic according to any one of claims 1 to 5, wherein the dielectric ceramic is at least .4.   A laminate in which dielectric layers comprising the dielectric ceramic according to any one of claims 1 to 6 and an internal electrode layer are alternately laminated, and provided on both end faces of the laminate, and connected to the internal electrode layer And a laminated ceramic capacitor, characterized in that the multilayer ceramic capacitor is composed of an external electrode.

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