JP2017078012A - Dielectric ceramic composition and multilayer ceramic capacitor including the same - Google Patents

Abstract

A dielectric ceramic composition with guaranteed X9R temperature characteristics and reliability and a multilayer ceramic capacitor including the dielectric ceramic composition are provided. A first main component represented by BaTiO3 and a second main component represented by Bi0.5 + aNa0.5 + aTiO3, and a mother represented by (1-z) BaTiO3-zBi0.5 + aNa0.5 + aTiO3. First, crystal grains containing material powder (0.05 ≦ z ≦ 0.5, −0.025 ≦ a ≦ 0.025), Bi content of less than 1.0 at%, and Na content of less than 5.0 at% When the crystal grain is a crystal grain having a Bi content of 1.0 to 70 at% and a Na content of 5.0 to 70 at%, the area ratio of the second crystal grain to the unit area is 5. Dielectric ceramic composition that is 0-50%. [Selection] Figure 2

Description

  The present invention relates to a dielectric ceramic composition in which X9R temperature characteristics and reliability are guaranteed, and a multilayer ceramic capacitor including the same.

  Generally, an electronic component using a ceramic material such as a capacitor, an inductor, a piezoelectric element, a varistor, or a thermistor includes a ceramic body made of a ceramic material, an internal electrode formed inside the ceramic body, An external electrode installed on the surface of the ceramic body so as to be connected to the electrode.

  Among the ceramic electronic components, the multilayer ceramic capacitor includes a plurality of laminated dielectric layers, an internal electrode disposed to face the dielectric layer, an external electrode electrically connected to the internal electrode, including.

  Multilayer ceramic capacitors are widely used as components of mobile communication devices such as computers, PDAs, and mobile phones because of their advantages of being small in size, ensuring high capacity, and being easy to mount.

  A multilayer ceramic capacitor is usually manufactured by laminating an internal electrode paste and a dielectric layer paste by a sheet method or a printing method and simultaneously firing them.

  In recent years, the proportion of electronic control devices in automobiles has increased, and with the development of hybrid automobiles and electric automobiles, the demand for multilayer ceramic capacitors that can be used at high temperatures of 150 ° C. or higher has gradually increased.

  Currently, there is a C0G-based dielectric material that can be fired in a reducing atmosphere and can be applied to a 200-degree guaranteed product. However, the dielectric constant is as low as about 30 to produce a high-capacity product. There is a problem that it is difficult.

In the case of BaTiO ₃ , the dielectric constant is as high as 1000 or higher, but since the dielectric constant is drastically decreased at a Curie temperature of 125 ° C. or higher, it is possible to guarantee the characteristics by 200 ° C., which is an area of 150 ° C. or higher Impossible.

  Therefore, there is a need for a material that has a high Curie temperature and maintains a relatively high dielectric constant to ensure reliability by satisfying the X9R temperature characteristics.

Korean Published Patent Publication No. 10-2012-0129918

  An object of the present invention is to provide a dielectric ceramic composition in which X9R temperature characteristics and reliability are ensured, and a multilayer ceramic capacitor including the same.

The dielectric ceramic composition according to an embodiment of the present invention includes a first main component represented by BaTiO ₃ and a second main component represented by Bi _{0.5 + a} Na _{0.5 + a} TiO ₃ . (1-z) BaTiO ₃ -zBi _{0.5 + a} Na _{0.5 + a} Base material powder represented by TiO ₃ (wherein z is 0.05 ≦ z ≦ 0.5, and a is −0.025 ≦ a) ≦ 0.025), a crystal grain having a Bi content of less than 1.0 at% and a Na content of less than 5.0 at% is defined as a first crystal grain, a Bi content of 1.0 to 70 at%, and a Na content of 5. When the crystal grains of 0 to 70 at% are used as the second crystal grains, the area ratio of the second crystal grains to the unit area is 5.0 to 50%.

  A multilayer ceramic capacitor according to another embodiment of the present invention includes a ceramic body in which dielectric layers and first and second internal electrodes are alternately stacked, and formed at both ends of the ceramic body. The first and second external electrodes electrically connected to the internal electrode, and the dielectric layer includes crystal grains having a Bi content of less than 1.0 at% and an Na content of less than 5.0 at%. When the crystal grain having a Bi content of 1.0 to 70 at% and the Na content of 5.0 to 70 at% is used as the second crystal grain, the area ratio of the second crystal grain to the unit area is 5 0.0 to 50%.

  According to an embodiment of the present invention, it is possible to implement a dielectric ceramic composition, a dielectric layer, and a multilayer ceramic capacitor including the dielectric ceramic composition that satisfy X9R temperature characteristics and have a high dielectric constant.

  In addition, by applying a sintering aid that can be fired at 1050 ° C. or less according to an embodiment of the present invention, Bi volatilization can be suppressed and the target characteristics of the multilayer ceramic capacitor of the present invention can be realized. .

It is a schematic diagram with respect to positions P1, P2, P3, and P4 in which the contents of Bi and Na are analyzed by STEM / EDS analysis within each crystal grain and the fine structure composed of the first crystal grain and the second crystal grain. It is a fine structure composed of the first crystal grains and the second crystal grains, and a fine structure corresponding to positions P1, P2, P3, and P4 in which the contents of Bi and Na are analyzed by STEM / EDS analysis in each crystal grain. It is the graph which measured Bi and Na content of P1-P4 of the 1st crystal grain. It is the graph which measured Bi and Na content of P1-P4 of the 2nd crystal grain. 1 is a schematic perspective view showing a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing the multilayer ceramic capacitor taken along VI-VI ′ of FIG. 5.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for a clearer description.

  The present invention relates to a dielectric ceramic composition, and examples of the electronic component including the dielectric ceramic composition include a capacitor, an inductor, a piezoelectric element, a varistor, and a thermistor. A multilayer ceramic capacitor will be described as an example of a component.

The dielectric ceramic composition according to an embodiment of the present invention includes a first main component represented by BaTiO ₃ and a second main component represented by Bi _{0.5 + a} Na _{0.5 + a} TiO ₃ ( 1-z) Base metal powder represented by BaTiO ₃ −zBi _{0.5 + a} Na _{0.5 + a} TiO ₃ (wherein z is 0.05 ≦ z ≦ 0.5, a is −0.025 ≦ a ≦ 0) .025).

  The dielectric ceramic composition according to an embodiment of the present invention can satisfy X9R (−55 ° C. to 200 ° C.) characteristics specified in EIA (Electronic Industries Association) standards.

  In more detail, according to an embodiment of the present invention, there is provided a dielectric ceramic composition that uses copper (Cu) as an internal electrode and can be fired in a reducing atmosphere in which the copper (Cu) is not oxidized.

  Further, by providing a multilayer ceramic capacitor using the same, it is possible to satisfy the above temperature characteristics and realize excellent reliability.

In particular, according to the present invention, BiTiO ₃ having a high dielectric constant and (Bi _{0.5 + a} Na _{0.5 + a} ) TiO ₃ having _a high Curie temperature are used, and a dielectric ceramic composition that can be fired at 1050 ° C. or less is used. The sample of composite form composed of two kinds of crystal grains each having these compositions in one sintered body is prepared, and the area ratio of these two crystal grains is controlled. By doing so, the target characteristics of the present invention could be realized.

  Hereinafter, each component of the dielectric ceramic composition according to one embodiment of the present invention will be described more specifically.

a) Base Material Powder A dielectric ceramic composition according to an embodiment of the present invention includes a first main component represented by BaTiO ₃ and a second main component represented by Bi _{0.5 + a} Na _{0.5 + a} TiO _3. And a base material powder represented by (1-z) BaTiO ₃ -zBi _{0.5 + a} Na _{0.5 + a} TiO ₃ (wherein z is 0.05 ≦ z ≦ 0.5, a is −0. 025 ≦ a ≦ 0.025).

  In the above formula, z can satisfy 0.05 ≦ z ≦ 0.5.

  Further, a can satisfy −0.025 ≦ a ≦ 0.025.

The first main component can be represented by BaTiO ₃ , and the BaTiO ₃ is a material used for a general dielectric base material and has a Curie temperature of about 125 degrees. It may be.

The first main component is not only a component represented by BaTiO ₃ but also modified by partially dissolving Ca, Zr, etc. (Ba _1-x Ca _x ) (Ti _1-y Ca _y ) O _3. Forms such as (BCTZ), Ba (Ti _1-y Zr _y ) O ₃ (BTZ) are also possible.

The second main component may be represented by Bi _{0.5 + a} Na _{0.5 + a} TiO ₃ .

The a may satisfy −0.025 ≦ a ≦ 0.025. Preferably, the second main component may be represented by Bi _0.5 Na _0.5 O ₃ .

That is, the base material powder of the dielectric ceramic composition according to one embodiment of the present invention is made of a BaTiO ₃ ferroelectric material having a low Curie temperature and a material represented by Bi _{0.5 + a} Na _{0.5 + a} TiO ₃ with _a certain amount. A mixed form may be used.

  A dielectric layer using a dielectric ceramic composition according to an embodiment of the present invention by preparing a base material powder by mixing the first main component and the second main component material at a constant ratio as described above. The multilayer ceramic capacitor has a high dielectric constant and can be fired at 1050 ° C. or lower, and in particular, can satisfy the X9R temperature characteristic.

The dielectric ceramic composition according to an embodiment of the present invention has a room temperature dielectric constant of 1000 or more, a room temperature resistivity of 1.0 × 10 ¹¹ Ohm · cm or more, a high temperature of less than 200 TCC (200 ° C.) ± 22%, and a high temperature (200 C.) All characteristics with a withstand voltage of 50 V / μm or more can be realized simultaneously.

  Moreover, the base material powder of the dielectric ceramic composition may be in a solid solution form other than the form in which materials having different Curie temperatures are mixed. When the base material powder is in the form of solid solution, the base material powder may have one or more phases. For example, a crystal grain having a Bi content of less than 1.0 at% and a Na content of less than 5.0 at% is defined as a first crystal grain, and a crystal having a Bi content of 1.0 to 70 at% and a Na content of 5.0 to 70 at%. When the grains are the second crystal grains, the base material powder may have a form having first and second crystal grains.

  FIG. 1 and FIG. 2 are schematic views of the fine structure composed of the first crystal grains and the second crystal grains and the positions P1, P2, P3, and P4 for analyzing the contents of Bi and Na by STEM / EDS analysis in each crystal grain. 3 is a graph in which the Bi and Na contents of P1 to P4 of the first crystal grains are measured, and FIG. 4 is a graph of the Bi and Na contents of P1 to P4 in the second crystal grains. It is a graph.

  Referring to FIGS. 1 and 2, the microstructure of the dielectric layer of the multilayer ceramic electronic component using the dielectric ceramic composition according to one embodiment of the present invention includes a first crystal grain 10 and a second crystal grain 20. And including.

  The first crystal grain 10 measures the Bi and Na contents at positions P1 to P4 in one of the crystal grains shown in FIGS. 1 and 2, and the Bi content is less than 1.0 at%. It means crystal grains having a Na content of less than 5.0 at%. That is, referring to FIG. 3, the Bi content and Na content of P1 to P4 are measured, and the average of four points is obtained, and crystals with Bi content of less than 1.0 at% and Na content of less than 5.0 at% are obtained. A grain can be defined as a first grain.

  The 2nd crystal grain 20 measures Bi and Na content in the position of P1-P4 in one of the crystal grains shown in FIG.1 and FIG.2, and Bi content is 1.0-70at%. , Means a crystal grain having a Na content of 5.0 to 70 at%. That is, referring to FIG. 4, the Bi content and Na content of P1 to P4 are measured, and the average of four locations is obtained, and the Bi content is 1.0 to 70 at%, and the Na content is 5.0 to 70 at%. These crystal grains can be defined as the second crystal grains.

  When the area ratio of the second crystal grains to the unit area is 5.0 to 50%, the dielectric ceramic composition according to the embodiment of the present invention can simultaneously realize all the above characteristics. That is, when the area ratio of the second crystal grains to the unit area is out of 5.0 to 50%, all the target characteristics of the present invention cannot be realized.

  The base material powder is not particularly limited, but the average particle size of the powder may be 300 nm or less.

b) First Subcomponent According to one embodiment of the present invention, the dielectric ceramic composition may further include an oxide or carbonate containing Li as the first subcomponent, preferably Li ₂ CO _3. Can further be included. The first subcomponent may be included in an amount of 0.2 mol to 5.0 mol with respect to 100 mol of the base material powder.

  The first subcomponent serves to improve the room temperature specific resistance and the high temperature withstand voltage characteristics of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied.

  When the first subcomponent is less than 0.2 mol with respect to 100 mol of the base material powder, there arises a problem that the sintered density is low and the normal temperature specific resistance and the high temperature withstand voltage are very low. When it exceeds 5.0 mol with respect to 100 mol of the base material powder, a problem that the high-temperature withstand voltage is as low as less than 50 V / μm may occur.

  Therefore, the dielectric ceramic composition according to the embodiment of the present invention has all the above characteristics when the content of the first subcomponent is 0.2 to 5.0 mol with respect to 100 mol of the base material powder. Simultaneous implementation is possible.

c) Second Subcomponent According to one embodiment of the present invention, the dielectric ceramic composition includes at least one of Mn, V, Cr, Fe, Ni, Co, Cu and Zn as the second subcomponent. In addition, an oxide or a carbonate containing bismuth can be further contained, and preferably, MnO ₂ or V ₂ O ₅ can be further contained.

  As the second subcomponent, the oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu and Zn is 0.2 mol to 100 mol of the base material powder. It can be included with a content of 3.0 mol.

  Alternatively, when two or more kinds of second subcomponents are included, the total content of the second subcomponents can be included so as to satisfy 0.2 to 3.0 at% based on at%.

  The second subcomponent serves to improve the room temperature specific resistance and high temperature withstand voltage characteristics of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied.

  When the total content of the second subcomponent is less than 0.2 at%, the normal temperature specific resistance and the high temperature withstand voltage characteristics may be deteriorated.

  Even when the total content of the second subcomponent exceeds 3.0 at%, the normal temperature specific resistance and the high temperature withstand voltage characteristics may be deteriorated.

  In particular, the dielectric ceramic composition according to an embodiment of the present invention may further include a second subcomponent having a content of 0.2 to 3.0 at% with respect to 100 at% of the base material powder, Thereby, low-temperature firing is possible, high high-temperature withstand voltage characteristics can be obtained, and all the above-described characteristics can be realized simultaneously.

d) Third Subcomponent According to one embodiment of the present invention, the dielectric ceramic composition comprises at least one selected from the group consisting of oxides and carbonates of one or more elements of Ba and Ca. A third subcomponent may be included, and preferably may further include BaCO ₃ .

  The third subcomponent may be included in a content of 0.2 to 10.0 mol with respect to 100 mol of the base material powder.

  When the third subcomponent is less than 0.2 mol with respect to 100 mol of the base material powder, there is a problem that the high-temperature withstand voltage is very low, and the first subcomponent is 10.0 mol with respect to 100 mol of the base material powder. In the case of exceeding, the problem that the sintered density is low and the high-temperature withstand voltage is low may occur.

  Therefore, the dielectric ceramic composition according to one embodiment of the present invention has all the above characteristics when the content of the third subcomponent is 0.2 to 10.0 mol with respect to 100 mol of the base material powder. Simultaneous implementation is possible.

e) Fourth Subcomponent According to one embodiment of the present invention, the dielectric ceramic composition is one or more selected from the group consisting of Si element oxide, Si element carbonate and Si element glass. A fourth subcomponent may be included, and preferably, SiO ₂ may further be included.

  The fourth subcomponent may be included in an amount of 0.2 to 5.0 mol with respect to 100 mol of the base material powder.

  When the content of the fourth subcomponent is less than 0.5 mol with respect to 100 mol of the base material powder, the sintering density is low, and the normal temperature resistivity and the high temperature withstand voltage may decrease. Even when the content exceeds 0.0 mol, the high-temperature withstand voltage may be lowered due to problems such as secondary phase generation.

  5 is a schematic perspective view showing a multilayer ceramic capacitor 100 according to an embodiment of the present invention, and FIG. 6 is a schematic cross-sectional view showing the multilayer ceramic capacitor 100 taken along VI-VI ′ of FIG. FIG.

  Referring to FIGS. 5 and 6, a multilayer ceramic capacitor 100 according to another embodiment of the present invention includes a ceramic body 110 in which dielectric layers 111 and first and second internal electrodes 121 and 122 are alternately stacked. . First and second external electrodes 131 and 132 that are electrically connected to first and second internal electrodes 121 and 122 that are alternately arranged inside the ceramic main body 110 are formed at both ends of the ceramic main body 110.

  The shape of the ceramic body 110 is not particularly limited, but may generally be a hexahedral shape. Moreover, the dimension in particular is not restrict | limited, You may make it an appropriate dimension according to a use, for example, (0.6-5.6 mm) * (0.3-5.0 mm) * (0.3-1) .9 mm).

  The thickness of the dielectric layer 111 can be arbitrarily changed according to the capacitance design of the capacitor. In one embodiment of the present invention, the thickness of the dielectric layer after firing is preferably 0 per layer. It may be 1 μm or more.

  Since the dielectric layer having a thickness that is too thin has a small number of crystal grains in one layer and adversely affects reliability, the thickness of the dielectric layer may be 0.1 μm or more.

  The first and second internal electrodes 121 and 122 are laminated so that the end faces are alternately exposed on the surfaces of the opposite ends of the ceramic body 110.

  The first and second external electrodes 131 and 132 are formed at both ends of the ceramic body 110 and are electrically connected to the exposed end surfaces of the first and second internal electrodes 121 and 122 arranged alternately. The capacitor circuit is configured.

The conductive material contained in the first and second internal electrodes 121 and 122 is not particularly limited, but the dielectric layer according to an embodiment of the present invention includes a first main component represented by BaTiO ₃ and Bi. _0.5 + _{a Na 0.5} + _a includes a second principal component represented by TiO _3, a _{(1-z) BaTiO 3 -zBi} 0.5 + a Na base powder represented by _0.5 + a TiO ₃ (provided that the z is 0.05 ≦ z ≦ 0.5, a is −0.025 ≦ a ≦ 0.025), and the first and second internal electrodes 121 and 122 are made of copper. (Cu) can be used.

  The thicknesses of the first and second internal electrodes 121 and 122 can be appropriately determined according to the application and the like, and are not particularly limited. For example, the thickness is 0.1 to 5 μm or 0.1 to 2. It may be 5 μm.

  The conductive material contained in the first and second external electrodes 131 and 132 is not particularly limited, but nickel (Ni), copper (Cu), or an alloy thereof may be used.

  The thicknesses of the first and second external electrodes 131 and 132 can be appropriately determined according to the application and the like, and are not particularly limited, but may be, for example, 10 to 50 μm.

  The dielectric layer 111 constituting the ceramic body 110 may include a dielectric ceramic composition according to an embodiment of the present invention.

The dielectric ceramic composition includes (1-z) BaTiO ₃ − containing _a first main component represented by BaTiO ₃ and a second main component represented by Bi _{0.5 + a} Na _{0.5 + a} TiO _3. It includes _a base material powder represented by zBi _{0.5 + a} Na _{0.5 + a} TiO ₃ (wherein z is 0.05 ≦ z ≦ 0.5 and a is −0.025 ≦ a ≦ 0.025).

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, this is to help a specific understanding of the invention, and the scope of the present invention is not limited by the examples. .

  After mixing ethanol and toluene with the compositions specified in Table 1, Table 3 and Table 5 below together with a dispersant, a binder was mixed to prepare a ceramic sheet.

  A copper (Cu) electrode is printed on the formed ceramic sheet and 21 layers are laminated to produce an active sheet, and a cover sheet (10 to 13 μm) is laminated to 25 layers as a cover located above and below the active sheet. A crimping bar was prepared by crimping.

  Thereafter, the crimp bar was cut into chips of 3.2 mm × 1.6 mm size using a cutting machine.

After the cut chip was calcined for binder removal, firing was performed at 1050 ° C. in a reducing atmosphere (N ₂ atmosphere), and an external electrode was formed on the fired chip with Cu paste.

As the main component base material, BaTiO ₃ and (Bi _0.5 Na _0.5 ) TiO ₃ powders having an average particle diameter of 300 nm were used.

  The raw material powder containing the main component and the subcomponent was mixed with ethanol / toluene, a dispersant and a binder using zirconia balls as a mixing / dispersing medium, and then ball milled for 20 hours.

  The produced slurry was produced into molded sheets having thicknesses of 3.5 μm and 10 to 13 μm using a doctor blade type coater.

  A copper (Cu) internal electrode was printed on the sheet having a thickness of about 10 μm.

  As the upper and lower cover layers, 25 layers of molded sheets having a thickness of 10 to 13 μm are laminated, and 21 sheets on which internal electrodes having a thickness of about 2.0 μm are printed are laminated to produce an active layer. To complete a multilayer ceramic capacitor.

  For the prototype multilayer ceramic capacitor (Proto-type MLCC) test piece completed as described above, the capacitance at room temperature and the dielectric loss were measured under the conditions of 1 kHz and AC 0.2 V / μm using an LCR meter. .

  The dielectric constant of the dielectric of the MLCC chip was calculated from the capacitance, the dielectric thickness of the MLCC chip, the area of the internal electrode, and the number of stacked layers.

  The room temperature insulation resistance was measured after 60 seconds with 10 samples taken and DC 10 V / μm applied.

  The change in capacitance with temperature was measured in the temperature range of −55 ° C. to 125 ° C.

  In the high-temperature IR boost experiment, the resistance degradation behavior was measured while increasing the voltage step by 5 V / μm at 150 ° C. The time for each step was 10 minutes, and the resistance value was measured at intervals of 5 seconds.

The high-temperature withstand voltage was derived from the high-temperature IR boosting experiment. The high-temperature withstand voltage was measured by applying a DC voltage of 5 V / μm per unit thickness of the dielectric at 150 ° C. for 10 minutes and continuously increasing the voltage step. Sometimes, it means a voltage at which IR becomes 10 ⁵ Ω or more.

  The RC value is a value obtained by multiplying the room temperature capacity value measured at AC 0.2 V / μm and 1 kHz by the insulation resistance value measured at DC 10 V / μm.

  Tables 2, 4 and 6 show characteristics of prototype multilayer ceramic capacitors (Proto-type MLCCs) to which Cu internal electrodes corresponding to the compositions specified in Tables 1, 3 and 5 are applied.

Table 1 shows that the first subcomponent Li ₂ CO _{3 is} 1.8 mol and the second subcomponent MnO _{2 is} 0.1 mol per 100 mol of the base material (1-z) BaTiO ₃ + z (Bi _0.5 Na _0.5 ) TiO ₃ . 5 mol, V ₂ O ₅ : 0 mol, third subcomponent BaCO ₃ : 1.0 mol, fourth subcomponent SiO ₂ : 1.0 mol, content of second main component (Bi _0.5 Na _0.5 ) TiO ₃ The composition of the examples according to the z value is shown, and Table 2 shows the characteristics of the prototype multilayer ceramic capacitor (Proto-type MLCC) corresponding to these compositions.

Referring to Table 2, when z is less than 0.05 (Examples 1 and 2), there is a problem that the high temperature TCC (200 ° C.) deviates from ± 22%, and z exceeds 0.5. In the case (Example 8), there is a problem that the normal temperature specific resistance is as low as less than 1.0 × 10 ¹¹ Ohm · cm and the high-temperature withstand voltage is as low as less than 50 V / μm. Therefore, when z satisfies 0.05 or more and 0.5 or less, the dielectric ceramic composition according to an embodiment of the present invention has a room temperature dielectric constant of 1000 or more and a room temperature resistivity of 1.0 × 10 ¹¹ Ohm. All the characteristics of cm or more, high temperature 200TCC (200 ° C.) ± 22% and high temperature (200 ° C.) withstand voltage 50 V / μm or more can be realized simultaneously. In such a case, it can be seen that the area ratio of the second crystal grains to the unit area belongs to the range of 5 to 50%.

Unlike this, Example 9 shows the characteristics of a single main component (Ba _0.9 Bi _0.1 Na _0.1 ) TiO ₃ solid solution, but the content of each atom of the main component is Although it is similar to Example 4 or 5, the area ratio of the 2nd crystal grain with respect to a unit area corresponds to 100%, and it turns out that the target characteristic of this invention is not embodied in such a case. Therefore, in order to implement the target characteristics of the present invention, the area ratio of the second crystal grains to the unit area needs to satisfy 5 to 50%.

In Examples 10 to 18 of Table 3, the second subcomponent MnO ₂ : 0.5 mol, V ₂ O _{5 with} respect to 100 mol of the base material 0.8BaTiO ₃ +0.2 (Bi _0.5 Na _0.5 ) TiO ₃ : 0 mol, third subcomponent BaCO ₃ : 1.0 mol, fourth subcomponent SiO ₂ : 1.0 mol, the composition of the experimental example according to the content of the first subcomponent Li ₂ CO ₃ is shown. Examples 10 to 18 show characteristics of prototype multilayer ceramic capacitors (Proto-type MLCCs) corresponding to these compositions.

When the content of Li ₂ CO ₃ is less than 0.2 mol (Examples 10 and 11), there is a problem that the sintering density is low, the room temperature specific resistance and the high temperature withstand voltage are very low, and Li ₂ It can be seen that even when the content of CO ₃ exceeds 5.0 mol (Example 18), there is a problem that the high-temperature withstand voltage is as low as less than 50 V / μm.

When the content of Li ₂ CO ₃ belongs to the range of 0.2 to 5.0 mol (Examples 12 to 17), the target room temperature dielectric constant of 1000 or more, room temperature specific resistance of 1E11 Ohm · cm or more, high temperature All characteristics of (200 degrees) TCC (200 ° C.) less than ± 22% and high temperature (200 degrees) withstand voltage of 50 V / μm or more can be realized simultaneously. Also at this time, it can be confirmed that the area ratio of the second crystal grains to the unit area belongs to the range of 5 to 50%.

In Examples 19 to 25 of Table 3, the first subcomponent Li ₂ CO ₃ : 1.8 mol with respect to the base material 0.8BaTiO ₃ +0.2 (Bi _0.5 Na _0.5 ) TiO ₃ 100 mol, 2 subcomponent _V 2 _O 5: _0mol, third subcomponent BaCO _3: 1.0 mol, fourth subcomponent _SiO 2: when it is 1.0 mol, the composition of the experimental example according to the second content of the subcomponent MnO ₂ Examples 19 to 25 in Table 4 show the characteristics of prototype multilayer ceramic capacitors (Proto-type MLCCs) corresponding to these compositions.

When the content of MnO ₂ is less than 0.2 mol (Example 19), there is a problem that the normal temperature specific resistance and the high-temperature withstand voltage are very low, and the content of MnO ₂ exceeds 3.0 mol. It can be confirmed that (Example 25) also has a problem that the room temperature resistivity and the high-temperature withstand voltage are lowered.

When the content of MnO ₂ belongs to the range of 0.2 to 3.0 mol (Examples 20 to 24), the room temperature dielectric constant of 1000 or more and the room temperature specific resistance of 1.0 × 10 ¹¹ Ohm. All the characteristics of cm or more, high temperature (200 degrees) TCC (200 ° C.) ± 22%, and high temperature (200 degrees) withstand voltage of 50 V / μm or more can be realized simultaneously. Also at this time, it can be confirmed that the area ratio of the second crystal grains to the unit area belongs to the range of 5 to 50%.

In Examples 26 to 30 in Table 3, the first subcomponent Li ₂ CO ₃ : 1.8 mol is used with respect to 100 mol of the base material 0.8BaTiO ₃ +0.2 (Bi _0.5 Na _0.5 ) TiO ₃ . The composition of the experimental example in the case where both the _second subcomponents MnO ₂ and V ₂ O ₅ are added when the third subcomponent BaCO _{3 is} 1.0 mol and the fourth subcomponent SiO ₂ is 1.0 mol is shown in Table Examples 4 to 30 of 4 show the characteristics of prototype multilayer ceramic capacitors (Proto-type MLCCs) corresponding to these compositions.

When Mn is added alone (Examples 20 to 24), or when both Mn and V are added (Examples 26 to 30), the total content of the second subcomponent is the same based on at%. It can be confirmed that the same characteristics are realized, and when the total content of the second subcomponent belongs to the range of 0.2 to 3.0 at% based on at% (Examples 20 to 24 or Examples 26 to 30), room temperature dielectric constant of 1000 or more, room temperature specific resistance of 1.0 × 10 ¹¹ Ohm · cm or more, high temperature (200 ° C.) TCC (200 ° C.) less than ± 22%, and high temperature (200 degrees) All characteristics with a withstand voltage of 50 V / μm or more can be realized simultaneously. Also at this time, it can be confirmed that the area ratio of the second crystal grains to the unit area belongs to the range of 5 to 50%.

In Examples 31 to 39 in Table 5, the first subcomponent Li ₂ CO ₃ : 1.8 mol with respect to 100 mol of the base material 0.8BaTiO ₃ +0.2 (Bi _0.5 Na _0.5 ) TiO ₃ , 2 sub-components MnO ₂ : 0.5 mol, V ₂ O ₅ : 0 mol, fourth sub-component SiO ₂ : 1.0 mol, shows the composition of the experimental example according to the content of the third sub-component BaCO ₃ , Nos. 6 to 31 to 39 show characteristics of the prototype multilayer ceramic capacitor (Proto-type MLCC) corresponding to these compositions.

When the content of the third subcomponent BaCO ₃ is less than 0.2 mol (Example 31), there is a problem that the high-temperature withstand voltage is low, and when the content of BaCO ₃ exceeds 10.0 mol (implementation) It can be confirmed that Example 39) also has a problem that the sintered density is low and the high-temperature withstand voltage is low. When the content of BaCO ₃ belongs to the range of 0.2 to 10.0 mol (Examples 32 to 38), the target room temperature dielectric constant of 1000 or more and the room temperature specific resistance of 1.0 × 10 ¹¹ Ohm · All the characteristics of cm or more, high temperature (200 degrees) TCC (200 ° C.) ± 22%, and high temperature (200 degrees) withstand voltage of 50 V / μm or more can be realized simultaneously. Also at this time, it can be confirmed that the area ratio of the second crystal grains to the unit area belongs to the range of 5 to 50%.

Examples 40 to 46 in Table 5 show that the first subcomponent Li ₂ CO _{3 is} 1.8 mol with respect to 100 mol of the base material 0.8BaTiO ₃ +0.2 (Bi _0.5 Na _0.5 ) TiO ₃ . 2 subcomponents MnO ₂ : 0.5 mol, V ₂ O ₅ : 0 mol, third subcomponent BaCO ₃ : 1.0 mol, the composition of the experimental example according to the content of the fourth subcomponent SiO ₂ is shown, Nos. 6, 40 to 46 show characteristics of prototype multilayer ceramic capacitors (Proto-type MLCCs) corresponding to these compositions.

In the case the content of the fourth subcomponent SiO ₂ is less than 0.2 mol (Example 40 and 41), room temperature resistivity and high temperature withstand voltage sintering density is low is a problem that low occurs, SiO ₂ It can be confirmed that there is also a problem that the high-temperature withstand voltage is lowered due to the formation of the secondary phase or the like even when the content of P exceeds 5.0 mol (Example 46). When the content of SiO ₂ belongs to the range of 0.2 to 5.0 mol (Examples 42 to 45), the target of the present invention is room temperature dielectric constant of 1000 or more, room temperature specific resistance 1.0 × 10 ¹¹ Ohm · All the characteristics of cm or more, high temperature (200 degrees) TCC (200 ° C.) ± 22%, and high temperature (200 degrees) withstand voltage of 50 V / μm or more can be realized simultaneously. Also at this time, it can be confirmed that the area ratio of the second crystal grains to the unit area belongs to the range of 5 to 50%.

  Although the embodiment of the present invention has been described in detail above, the scope of the right of the present invention is not limited to this, and various modifications and modifications can be made without departing from the technical idea of the present invention described in the claims. It will be apparent to those skilled in the art that variations are possible.

DESCRIPTION OF SYMBOLS 100 Multilayer ceramic capacitor 110 Ceramic body 111 Dielectric layer 121,122 1st and 2nd internal electrode 131,132 1st and 2nd external electrode

Claims (12)

A first main component represented by BaTiO ₃ and a second main component represented by Bi _{0.5 + a} Na _{0.5 + a} TiO ₃ , and (1-z) BaTiO ₃ −zBi _{0.5 + a} Na _{0. 5 + a} TiO ₃ base material powder (wherein, z is 0.05 ≦ z ≦ 0.5, a is −0.025 ≦ a ≦ 0.025),
A crystal grain having a Bi content of less than 1.0 at% and a Na content of less than 5.0 at% is defined as a first crystal grain, and a crystal grain having a Bi content of 1.0 to 70 at% and a Na content of 5.0 to 70 at% is provided. When it is the second crystal grain,
A dielectric ceramic composition, wherein an area ratio of the second crystal grains to a unit area is 5.0 to 50%. As the first subcomponent, the _Li 2 CO _3, including 0.2~5.0mol against base powder 100 mol, the dielectric ceramic composition of claim 1. 3. The dielectric ceramic composition according to claim 1, wherein 0.2 to 3.0 mol of MnO ₂ or V ₂ O ₅ is contained as a second subcomponent with respect to 100 mol of the base material powder. The dielectric ceramic composition according to any one of claims 1 to 3, wherein 0.2 to 10.0 mol of BaCO3 is contained as a _third subcomponent with respect to 100 mol of the base material powder. 5. The dielectric ceramic composition according to claim 1, wherein SiO ₃ is contained as a fourth subcomponent in an amount of 0.2 to 5.0 mol with respect to 100 mol of the base material powder. A ceramic body in which dielectric layers and first and second internal electrodes are alternately stacked;
First and second external electrodes formed at both ends of the ceramic body and electrically connected to the first and second internal electrodes,
The dielectric layer has, as a first crystal grain, a crystal grain having a Bi content of less than 1.0 at% and a Na content of less than 5.0 at%, a Bi content of 1.0 to 70 at%, and a Na content of 5.0 to A multilayer ceramic capacitor in which an area ratio of the second crystal grains to a unit area is 5.0 to 50% when 70 at% crystal grains are used as second crystal grains. The dielectric layer includes a first main component represented by BaTiO ₃ and a second main component represented by Bi _{0.5 + a} Na _{0.5 + a} TiO ₃ , and (1-z) BaTiO ₃ −zBi. _{0.5 + a} Na _{0.5 + a} TiO ₃ base material powder (wherein z is 0.05 ≦ z ≦ 0.5 and a is −0.025 ≦ a ≦ 0.025) The multilayer ceramic capacitor according to claim 6, which is formed using a porcelain composition. The multilayer ceramic capacitor according to claim 7, wherein the dielectric ceramic composition includes 0.2 to 5.0 mol of Li ₂ CO ₃ with respect to 100 mol of the base material powder as a first subcomponent. The multilayer ceramic capacitor according to claim 7 or 8, wherein the dielectric ceramic composition includes 0.2 to 3.0 mol of MnO ₂ or V ₂ O ₅ as a _second subcomponent with respect to 100 mol of the base material powder. . 10. The multilayer ceramic capacitor according to claim 7, wherein the dielectric ceramic composition includes 0.2 to 10.0 mol of BaCO ₃ as a _third subcomponent with respect to 100 mol of the base material powder. 11. . 11. The multilayer ceramic capacitor according to claim 7, wherein the dielectric ceramic composition includes 0.2 to 5.0 mol of SiO ₂ with respect to 100 mol of a base material powder as a fourth subcomponent. .   The multilayer ceramic capacitor according to claim 6, wherein the first and second internal electrodes include copper (Cu).