KR102184672B1 - Dielectric ceramic composition and multilayer ceramic capacitor including the same - Google Patents

Abstract

The invention of claim 1 includes a base material powder and a subcomponent including a main component and second main component, wherein the first main component (K _y Na _{1 -y) -} and the (Nb _{1 z} Ta _z) O _3, the second main component is BaTiO _3, wherein the base material powder _{(1-x) (K y} Na 1 -y) (Nb 1 - z Ta z) O 3 - x BaTiO 3 When, x is 0.05≦x≦0.4, y is 0≦y≦0.7, and z is 0≦z≦0.7.

Description

Dielectric ceramic composition and multilayer ceramic capacitor including the same}

The present invention relates to a dielectric ceramic composition with guaranteed X8R or X9S temperature characteristics and reliability, and a multilayer ceramic capacitor including the same.

In general, electronic components using ceramic materials such as capacitors, inductors, piezoelectric elements, varistors, or thermistors are ceramic bodies made of ceramic materials, internal electrodes formed inside the body, and external electrodes installed on the surface of the ceramic body to be connected to the internal electrodes. It is equipped with.

Among ceramic electronic components, a multilayer ceramic capacitor includes a plurality of stacked dielectric layers, internal electrodes disposed opposite to each other with one dielectric layer therebetween, and external electrodes electrically connected to the internal electrodes.

Multilayer ceramic capacitors are widely used as parts of mobile communication devices such as computers, PDAs, and mobile phones due to the advantages of small size, high capacity, and easy mounting.

Multilayer ceramic capacitors are generally manufactured by laminating an internal electrode paste and a dielectric layer paste by a sheet method or a printing method, followed by simultaneous firing.

Recently, due to the increasing proportion of electronic control devices in automobiles, and the development of hybrid vehicles and electric vehicles, the demand for multilayer ceramic capacitors that can be used at high temperatures of 150 degrees or higher is increasing.

Currently, there is a C0G-series dielectric as a dielectric material that can be fired in a reducing atmosphere and can be applied to products with a 200 degree guarantee, but the dielectric constant is very low around 30, making it difficult to manufacture high-capacity products.

In the case of BaTiO ₃ , the dielectric constant is as high as 1000 or higher, but the dielectric constant falls sharply at a Curie temperature of 125 degrees or higher, so it is impossible to guarantee the characteristics up to 200 degrees, which is a region above 150 degrees.

As a way to increase the Curie temperature of BaTiO ₃ , there is a method of dissolving Pb in Ba-site. Pb is classified as an environmentally regulated substance, so there are many restrictions on its use.

In addition perop containing BaTiO ₃ material and a Bi Sky agent (perovskite) material is _{Bi (Mg 0.5 Ti 0.5) O} 3, (Bi 0. 5 Na 0. 5) TiO 3, Bi (Zn 0.5 Ti 0.5) O 3 It is known that materials such as, BiScO _3, etc. increase the Curie temperature and realize stable high-temperature dielectric constant, but these materials can be fired only in an air atmosphere.

That _{is, Bi (Mg 0.5 Ti 0.5)} O 3, (Bi 0. 5 Na 0. 5) TiO 3, Bi (Zn 0.5 Ti 0.5) O 3, laminate containing Ni internal electrodes using materials such as BiScO ₃ In the case of manufacturing a ceramic capacitor, there is a problem that it is difficult to use because the insulation resistance is rapidly lowered during firing in a reducing atmosphere.

Na(Nb,Ta)O ₃ is known as a dielectric material for high-temperature capacitors that can be fired in a reducing atmosphere, but the cost of Nb and Ta, which are the starting materials for Na(Nb, Ta)O ₃ , is very high. There is a disadvantage of occupying a specific weight, and there is a problem that the insulation resistance characteristic is weaker than that of BaTiO ₃ .

In addition, in the case of BaTi ₂ O ₅ , the Curie temperature is known to be about 500 degrees. Even in the case of BaTi ₂ O ₅ , firing is possible only in an air atmosphere, and there is a problem in that the reduction resistance and insulation resistance are weak.

Therefore, even when firing in a reducing atmosphere, it is necessary to develop a dielectric material capable of realizing normal insulation resistance while having a higher Curie temperature than BaTiO ₃ .

Japanese Laid-Open Patent Publication No. 2009-025614

The present invention is to provide a dielectric ceramic composition capable of realizing normal insulation resistance while having a higher Curie temperature than BaTiO ₃ even when firing in a reducing atmosphere, and a multilayer ceramic capacitor including the same.

In addition, the present invention is to provide a dielectric ceramic composition capable of firing in a reducing atmosphere and having effects such as high dielectric constant, high insulation resistance, and high Curie temperature, and a multilayer ceramic capacitor including the same.

The dielectric ceramic composition according to an embodiment of the present invention includes a base material powder and a subcomponent including a first main component and a second main component, and the first main component is (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ , and the second main component is BaTiO ₃ , and the base powder is (1-x) (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ -x BaTiO ₃ When, x is 0.05 ≤ x ≤ 0.4, y is 0 ≤ y ≤ 0.7, and z is 0 ≤ z ≤ 0.7.

A multilayer ceramic capacitor according to another embodiment of the present invention includes a ceramic body including a dielectric layer and an internal electrode; And an external electrode disposed outside the ceramic body and connected to the internal electrode, wherein the dielectric layer includes first and second crystal grains, and the first crystal grain has a Ba content of 10 at % Or less, Ti content is less than 10 at%, and the second crystal grains have a Ba content of 10 at% or more and a Ti content of 10 at% or more, the area ratio of the second grains to the total area is 4.7 % To 37.9%.

According to the dielectric ceramic composition and the multilayer ceramic capacitor according to an embodiment of the present invention, the target characteristic of the present invention is 1E11 Ohm-cm or more, high temperature 200 degree withstand voltage 50V/㎛ or more, TCC (150°C)±15% It is possible to implement all characteristics of less than, TCC (200℃) ±22%, and a dielectric constant of 400 or more at room temperature at the same time.

1 is a schematic diagram of a microstructure composed of a first grain and a second grain, and positions P1, P2, P3, and P4 in which the contents of Ba and Ti are analyzed by STEM/EDS analysis in each grain.
2 is a schematic perspective view showing a multilayer ceramic capacitor according to an embodiment of the present invention.
3 is a schematic cross-sectional view illustrating a multilayer ceramic capacitor taken along line III-III′ of FIG. 2.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided in order to more completely explain the present invention to those with average knowledge in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity, and elements indicated by the same reference numerals in the drawings are the same elements.

The present invention relates to a dielectric ceramic composition, and an electronic component including the dielectric ceramic composition includes a capacitor, an inductor, a piezoelectric element, a varistor, or a thermistor. Hereinafter, as an example of a dielectric ceramic composition and an electronic component, a multilayer ceramic capacitor Explain.

The base material powder of the dielectric ceramic composition according to an embodiment of the present invention includes a first main component represented by (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ and a second main component represented by BaTiO ₃ do. At this time, the mother material powder is _{(1-x) (K y} Na 1 -y) is represented by _{x BaTiO 3 - - O 3 (} Nb 1 z Ta z).

When x satisfies 0.05 to 0.4, the target characteristic of the present invention, room temperature resistivity is 1E11 Ohm-cm or more, high temperature 200 degree withstand voltage 50V/㎛ or more, TCC(150℃)±15% or less, TCC(200℃)± It is possible to realize all characteristics of less than 22% and above 400 at room temperature.

In addition, y may be 0≦y≦0.7, and z may be 0≦z≦0.7.

The dielectric ceramic composition according to an embodiment of the present invention is X8R (-55°C to 150°C, ΔC/C ₀ ±15%) or X9S (-55°C to 200°C, △) specified in the Electronic Industries Association (EIA) standard. C/C ₀ ±22%) characteristics can be satisfied.

More specifically, according to an embodiment of the present invention, a dielectric ceramic capable of maintaining insulation resistance even when nickel (Ni) is used as an internal electrode of a multilayer ceramic capacitor and is fired in a reducing atmosphere in which nickel (Ni) is not oxidized. The composition is provided. In addition, by providing a multilayer ceramic capacitor using the same, each effect of high dielectric constant, high insulation resistance, and high Curie temperature can be simultaneously implemented.

In the present invention, BaTiO ₃ having a high dielectric constant and (K,Na)NbO ₃ having a high Curie temperature It includes together as a base material powder. In addition, a part of Nb of B-sited of (K,Na)NbO ₃ is applied as Ta to improve insulation resistance during firing in a reducing atmosphere.

Therefore, in the present invention, by using a dielectric ceramic composition that can be fired in a reducing atmosphere, a sample in the form of a composite composed of two kinds of crystal grains having different compositions in one sintered body can be prepared, and the area ratio of these two grains can be controlled. By doing so, the target characteristics of the present invention can be implemented.

Hereinafter, each component of the dielectric ceramic composition according to an embodiment of the present invention will be described in more detail.

a) base powder

The base material powder of the dielectric ceramic composition according to the embodiment of the present invention is (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ (where y is 0 ≤ y ≤ 0.7, z is 0 ≤ z ≤ 0.7) and a second main component represented by BaTiO ₃ . At this time, the base powder is represented by (1-x) (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ -x BaTiO ₃ .

When x satisfies 0.05 to 0.4, the target characteristic of the present invention, room temperature resistivity is 1E11 Ohm-cm or more, high temperature 200 degree withstand voltage 50V/㎛ or more, TCC(150℃)±15% or less, TCC(200℃)± It is possible to realize all characteristics of less than 22% and above 400 at room temperature.

Is _{- (z} Ta _z Nb ₁₎ can be represented by O _3, and the Curie temperature varies depending on a ratio of K and Na, however, the Curie temperature in the case where y is 0.5 a first main component (K _y Na _{1 -y)} It is high near 400 degrees.

In the first main component, when y is 0.1 or more, the room temperature dielectric constant can be improved to 800 or more. When y exceeds 0.7, there is a problem that the room temperature resistivity decreases rapidly and falls below 1E11 Ohm-cm. That is, in order to increase the room temperature dielectric constant to 800 or more while maintaining the room temperature specific resistance to 1E11 Ohm-cm or more, y may be 0.1 to 0.7.

In addition, in the first main component, as z increases, the room temperature specific resistance can be improved. When z exceeds 0.7, there is a problem that the room temperature dielectric constant decreases sharply and falls below 400. That is, in order to increase and maintain the room temperature specific resistance and at the same time maintain the room temperature dielectric constant above 400, z may be 0 to 0.7.

That is, K and Ta of the first main component are in a complementary relationship. Therefore, it is possible to increase the room temperature dielectric constant to 800 or more while maintaining the room temperature specific resistance of 1E11 Ohm-cm or more by simultaneously including K and Ta in the first main component.

The second main component may be represented by BaTiO _3, BaTiO ₃ is used as a material used for a general dielectric base material, the Curie temperature of the ferroelectric material can be about 125 degrees.

The second main component is (Ba _{1 - x} Ca _x ) (Ti _{1 - y} Ca _y ) O ₃ , Ba(Ti _1-y Zr _y ) modified by partially solid solution of Ca and Zr as well as the component represented by BaTiO ₃ Forms such as O ₃ are also possible.

That is, the base material powder of the dielectric ceramic composition according to an embodiment of the present invention may be in a form in which a first main component having a high Curie temperature and a second main component having a high dielectric constant are mixed or dissolved in a predetermined ratio.

In the dielectric ceramic composition according to an embodiment of the present invention, since the first main component and the second main component material are mixed in a predetermined ratio as described above to prepare a base material powder and use the same, firing in a reduced atmosphere is possible.

1 is a schematic diagram of a microstructure composed of a first grain and a second grain, and positions P1, P2, P3, and P4 in which the contents of Ba and Ti are analyzed by STEM/EDS analysis in each grain.

Referring to FIG. 1, the microstructure of the dielectric layer manufactured using the dielectric ceramic composition according to an embodiment of the present invention (reduction atmosphere, firing temperature: 1100 to 1150°C) has a Ba content of less than 10 at% and a Ti content of First crystal grains 10 having less than 10 at% and second grains 20 having a Ba content of 10 at% or more and a Ti content of 10 at% or more.

The content of Ti and Ba in one crystal grain was derived as the average value of the data at four locations by measuring each content (at%) of Ti and Ba at each point of P1 to P4.

The dielectric layer and the multilayer ceramic capacitor using the dielectric ceramic composition according to an embodiment of the present invention may simultaneously have effects of high dielectric constant, high insulation resistance, and high Curie temperature.

In more detail, the dielectric layer manufactured using the dielectric ceramic composition according to an embodiment of the present invention and a multilayer ceramic capacitor including the same have an area ratio of the second crystal grains of 4.7 to 37.9% with respect to the total area. The target characteristics of room temperature resistivity of 1E11 Ohm-cm or more, high temperature 200 degree withstand voltage 50V/㎛ or more, TCC(150℃)±15% or less, TCC(200℃)±22%, and room temperature dielectric constant 400 or more Simultaneous implementation is possible.

In addition, since the dielectric layer manufactured using the dielectric ceramic composition according to the embodiment of the present invention and the multilayer ceramic capacitor including the same have an area ratio of the second crystal grains of 4.7 to 37.9% with respect to the total area, EIA (Electronic Industries Association) specifications specified in X8R (-55℃~150℃, △C/C ₀ ±15%) or X9S (-55℃~200℃, △C/C ₀ ±22%) can be satisfied.

If the area ratio of the second grain is less than 4.7% of the total area, the room temperature specific resistance is less than 1E11 Ohm-cm, and if it exceeds 37.9%, X8R (-55℃~150℃, △C/C ₀ ±15% ) Or X9S (-55℃~200℃, △C/C ₀ ±22%).

That is, if the area ratio of the second crystal grains to the total area is out of 4.7% to 37.9%, some of the target characteristics of the present invention cannot be implemented.

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

b) the first subcomponent

According to an embodiment of the present invention, the dielectric ceramic composition may further include an oxide or carbonate containing Li as a first subcomponent, and preferably further include Li ₂ CO ₃ . The first accessory ingredient may be included from 0.25 mol to 5.0 mol based on 100 mol of the base material powder.

That is, the content of the first subcomponent is Li ₂ CO ₃ contained with respect to 100 mol of the base powder It may be included so that the content of the Li element satisfies 0.5 mol to 10.0 mol.

The first 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.

If the first subcomponent is less than 0.25 mol per 100 mol of the base powder, the sintering density is low, so that the room temperature specific resistance and high temperature withstand voltage are very low.If the first subcomponent exceeds 5.0 mol for 100 mol of the base powder, the high temperature withstand voltage is 50 A problem of lowering to less than V/㎛ may occur.

Accordingly, in the dielectric ceramic composition according to an embodiment of the present invention, when the content of the first subcomponent is 0.25 to 5.0 mol with respect to 100 mol of the base material powder, all the above-described properties can be simultaneously implemented. Even at this time, it can be seen that the area ratio of the second crystal grains to the total area satisfies 4.7% to 37.9%.

c) second subcomponent

According to an embodiment of the present invention, the dielectric ceramic composition is an oxide or carbonate of a variable valence acceptor element of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn as a second subcomponent. It may further include one or more selected from the group consisting of, preferably may further include MnO ₂ or V ₂ O ₅ .

As the second subcomponent, an oxide or carbonate including at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn may be included in an amount of 0.1 mol to 3.0 mol with respect to 100 mol of the base powder. have.

That is, the content of the second subcomponent may be included such that the content of the variable valence acceptor element included in the second subcomponent satisfies 0.1 mol to 3.0 mol with respect to 100 mol of the base powder.

Alternatively, when two or more types of second subcomponents are included, the total content of the variable valence acceptor element included in the second subcomponent may be included to satisfy 0.1 mol to 3.0 mol with respect to 100 mol of the base powder.

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.

If the total content of the variable valence acceptor element included in the second subcomponent is less than 0.1 mol, the room temperature specific resistance and high temperature withstand voltage characteristics may be deteriorated.

Even when the total content of the variable valence acceptor element included in the second subcomponent exceeds 3.0 mol, the room temperature specific resistance and high temperature withstand voltage characteristics may be deteriorated.

In particular, the dielectric ceramic composition according to an embodiment of the present invention may include such that the total content of the variable valence acceptor element included in the second subcomponent satisfies 0.1 mol to 3.0 mol with respect to 100 mol of the base material powder. Low temperature firing is possible, high high temperature withstand voltage characteristics can be obtained, and all the above-described characteristics can be simultaneously implemented.

Even at this time, it can be seen that the area ratio of the second crystal grains to the total area satisfies 4.7% to 37.9%.

d) third subcomponent

According to an embodiment of the present invention, the dielectric ceramic composition may include a third subcomponent including at least one selected from the group consisting of an oxide of an Si element, a carbonate of an Si element, and a glass containing an Si element, Preferably it may further include SiO ₂ .

The third accessory ingredient may be included in an amount of 0.1 to 5.0 mol with respect to 100 mol of the base material powder. That is, the content of the third accessory ingredient is SiO ₂ contained with respect to 100 mol of the base powder It may be included so that the content of the Si element satisfies 0.1 mol to 5.0 mol.

If the content of the third sub-component is less than 0.1 mol with respect to 100 mol of the base powder, the sintering density is low, so that the room temperature specific resistance and high temperature withstand voltage may be lowered, and even if it is contained in excess of 5.0 mol, secondary phase generation, etc. The high temperature withstand voltage can be lowered as a problem.

Even at this time, it can be seen that the area ratio of the second crystal grains to the total area satisfies 4.7% to 37.9%.

FIG. 2 is a schematic perspective view of the multilayer ceramic capacitor 100 according to an exemplary embodiment of the present invention, and FIG. 3 is a schematic cross-sectional view of the multilayer ceramic capacitor 100 taken along III-III′ of FIG. 2.

2 and 3, a multilayer ceramic capacitor 100 according to another embodiment of the present invention includes a ceramic body 110 in which a dielectric layer 111 and first and second internal electrodes 121 and 122 are alternately stacked. ). At both ends of the ceramic body 110, first and second external electrodes 131 and 132 that are alternately arranged inside the ceramic body 110 and electrically conductive with the first and second internal electrodes 121 and 122, respectively. Is formed.

Although there is no particular limitation on the shape of the ceramic body 110, it may generally have a hexahedral shape. Further, the dimension is not particularly limited, and may be an appropriate dimension depending on the application, for example (0.6 to 5.6 mm) × (0.3 to 5.0 mm) × (0.3 to 1.9 mm).

The thickness of the dielectric layer 111 can be arbitrarily changed according to the capacity design of the capacitor. In one embodiment of the present invention, the thickness of the dielectric layer after firing may be preferably 0.1 μm or more per layer.

The dielectric layer having a too thin thickness may have a thickness of 0.1 µm or more because the number of crystal grains in one layer is small and adversely affects reliability.

The first and second internal electrodes 121 and 122 are stacked so that their respective cross sections are alternately exposed on the surfaces of 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 alternately arranged first and second internal electrodes 121 and 122. Construct a capacitor circuit.

The conductive material contained in the first and second internal electrodes 121 and 122 is not particularly limited, but the dielectric layer 111 according to an embodiment of the present invention uses the dielectric ceramic composition according to the embodiment of the present invention. Is formed.

The base material powder of the dielectric ceramic composition according to an embodiment of the present invention is (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ (however, y is 0 ≤ y ≤ 0.7, z is 0 ≤ z ≤ 0.7) and a second main component represented by BaTiO ₃ . At this time, the base powder is represented by (1-x) (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ -x BaTiO ₃ , and x satisfies 0.05 to 0.4.

The thickness of the first and second internal electrodes 121 and 122 may be appropriately determined depending on the use, etc., and is not particularly limited, but may be, for example, 0.1 to 5 μm or 0.1 to 2.5 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 thickness of the first and second external electrodes 131 and 132 may be appropriately determined according to use, etc., and is not particularly limited, but may be, for example, 10 to 50 μm.

Hereinafter, the present invention will be described in more detail through Examples and Comparative Examples, but this is to aid in a specific understanding of the present invention, and the scope of the present invention is not limited by the Examples.

In the compositions specified in Tables 1, 3, and 5 below, ethanol and toluene were used as solvents and mixed together with a dispersant, and then a binder was mixed to prepare a ceramic sheet.

As the main component base material, (K,Na)(Nb,Ta)O ₃ and BaTiO ₃ powders with an average particle size of 300 nm were used.

An active sheet is manufactured by laminating 21 layers by printing nickel (Ni) electrodes on the molded ceramic sheet. Cover sheets (10 ~ 13㎛) are stacked in 25 layers on the upper and lower portions of the active sheet. It was compressed to produce a compression bar.

Thereafter, the pressing bar was cut into chips having a size of 3.2 mm × 1.6 mm using a cutter.

The cut chips were calcined for binder removal, and then calcined at 1100 to 1150° C. in a reducing atmosphere (N ₂ atmosphere), and an external electrode was formed with Cu paste on the fired chip.

Room temperature capacitance and dielectric loss (DF) for the prototype multilayer ceramic capacitor (Proto-type MLCC) specimen completed as described above were measured at 1 kHz and AC 0.5V/㎛ conditions using an LCR meter.

The dielectric constant of the multilayer ceramic capacitor was calculated from the capacitance, the dielectric thickness of the multilayer ceramic capacitor, the internal electrode area, and the number of layers.

The room temperature insulation resistance was measured after 60 seconds elapsed in a state where 10 samples were taken and DC 10 V/㎛ was applied.

The change in capacitance with temperature was measured in the temperature range of -55 °C to 200 °C.

In the high-temperature IR boosting experiment, the resistance deterioration behavior was measured by increasing the voltage step by 5V/µm at 200°C. The time for each step was 10 minutes and the resistance value was measured at intervals of 5 seconds.

High-temperature withstand voltage was derived from the high-temperature IR boosting experiment. When measuring with a voltage step of dc 5V/㎛ per dielectric unit thickness at 200℃ for 10 minutes and increasing this voltage step continuously, the IR is 10 ⁵ Ω or more. It means the voltage to withstand

The RC value is the product of the room temperature capacity value measured at AC 0.5V/㎛, 1kHz and the insulation resistance value measured at DC 10V/㎛.

Tables 2, 4, and 6 show the properties of a prototype multilayer ceramic capacitor (Proto-type MLCC) to which nickel (Ni) internal electrodes corresponding to the compositions specified in Tables 1, 3, and 5 are applied.

Examples 1 to 10 of Table 1 are the base powder (1-x) (K _y Na _{1 -y} )(Nb _{1 - z} Ta _z )O ₃ -x BaTiO ₃ (y, z = 0.2): When the first sub-component Li ₂ CO ₃ : 2.5 mol, the second sub-component MnO ₂ : 0.5 mol, and the third sub-component SiO ₂ : 0.5 mol relative to 100 mol, the examples according to x are shown. , Table 2 shows the characteristics of a prototype multilayer ceramic capacitor fired in a reducing atmosphere including a dielectric layer and a nickel (Ni) internal electrode prepared using the dielectric ceramic compositions of Examples 1 to 10 of Table 1.

When the composition ratio x of the second main component BaTiO ₃ is less than 0.05 (Examples 1 and 2), there is a problem that the room temperature specific resistance is lowered to less than 1E11 Ohm-cm, and the high temperature withstand voltage is lowered to less than 50 V/µm.

In addition, when the composition ratio x of the second main component BaTiO3 exceeds 0.4 (Examples 9 and 10), high temperature (150°C) TCC (150°C) exceeds ±15%, and high temperature (200°C) TCC (200°C) There is a problem that exceeds ±22%.

That is, when the composition ratio x of the second main component BaTiO3 satisfies the range of 0.05 to 0.4 (Examples 3 to 8), the room temperature specific resistance of the present invention is 1E11 Ohm-cm or more, high temperature 200 degree withstand voltage 50V/㎛ or more, TCC (150 ℃) less than ±15%, TCC (200℃) less than ±22%, and all characteristics of room temperature dielectric constant of 400 or more can be simultaneously implemented.

Using the dielectric composition according to an embodiment of the present invention, in a reducing atmosphere (N ₂ atmosphere), a dielectric layer is manufactured by firing at 1100° C. to 1150° C., or a nickel (Ni) internal electrode is printed thereto to manufacture a multilayer ceramic capacitor. In this case, the microstructure of the dielectric layer includes first grains and second grains.

The contents of Ba and Ti at P1 to P4 and four points in one crystal grain were analyzed by STEM/WDS or STEM/EELS.

As a result of calculating using the average value of the Ba and Ti contents at four points, the first grain is defined as a grain with “Ba content less than 10 at%, Ti content less than 10 at%”, and the second grain is “Ba content This is defined as a crystal grain having 10 at% or more and a Ti content of 10 at% or more.

Referring to Examples 1 to 10 of Table 1, in order to achieve the target characteristics of the present invention, the dielectric layer of the multilayer ceramic capacitor includes first and second grains, and the area ratio of the second grains to the total area is 4.7%. To 37.9%.

That is, when observing the microstructure of the dielectric layer of the multilayer ceramic capacitor, when the area ratio of the second grains per unit area is 4.7% to 37.9%, the room temperature specific resistance of the present invention is 1E11 Ohm-cm or more, and the high temperature 200 degree withstand voltage 50V/ ㎛ or more, TCC (150 ℃) less than ±15%, TCC (200 ℃) less than ±22%, and room temperature dielectric constant 400 or more can be implemented at the same time.

Examples 11 to 17 of Table 3 are the base powder 0.9 (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ -0.1 BaTiO ₃ (z = 0.2): When the first sub-component Li ₂ CO ₃ : 2.5 mol, the second sub-component MnO ₂ : 0.5 mol, and the third sub-component SiO ₂ : 0.5 mol relative to 100 mol, examples according to y are shown, and the table 4 shows the characteristics of a prototype multilayer ceramic capacitor fired in a reducing atmosphere including a dielectric layer and a nickel (Ni) internal electrode prepared using the dielectric ceramic compositions of Examples 11 to 17 of Table 3.

It can be seen that the room temperature dielectric constant improves as the value of the composition ratio y of K of the first main component increases, but when the value of the composition ratio y of K exceeds 0.7 (Example 17), the room temperature specific resistance is less than 1E11 Ohm-cm And the high temperature withstand voltage is lowered to less than 50 V/µm.

That is, when the value of the composition ratio y of K is 0.7 or less (Examples 11 to 16), the room temperature specific resistance of the present invention is 1E11 Ohm-cm or more, high temperature 200 degree withstand voltage 50V/㎛ or more, TCC (150°C) ±15% or less , TCC(200℃) ±22% or less, and room temperature permittivity of 400 or more can be simultaneously implemented.

In addition, the value of the composition ratio y of K may be 0.1 or more in order to increase the room temperature dielectric constant to 800 or more. As the value of y increases, the room temperature dielectric constant increases and then decreases. As described above, when the value of y exceeds 0.7 (Example 17), the room temperature specific resistance decreases to less than 1E11 Ohm-cm, There is a problem that the high temperature withstand voltage is lowered to less than 50 V/µm. Therefore, in order to improve the room temperature dielectric constant to 800 or more, and at the same time maintain the room temperature specific resistance of 1E11 Ohm-cm or more, and to maintain the high temperature withstand voltage of 50 V/µm or more, the value of y may satisfy 0.1 to 0.7.

Even at this time, it can be seen that the area ratio of the second crystal grains to the total area falls within the range of 4.7% to 37.9%.

Examples 18 to 23 of Table 3 are the base powder 0.9 (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ -0.1 BaTiO ₃ (y = 0.2): When the first sub-component Li ₂ CO ₃ : 2.5 mol, the second sub-component MnO ₂ : 0.5 mol, and the third sub-component SiO ₂ : 0.5 mol relative to 100 mol, examples according to z are shown, and the table 4 shows the characteristics of a prototype multilayer ceramic capacitor fired in a reducing atmosphere including a dielectric layer and a nickel (Ni) internal electrode prepared by using the dielectric ceramic compositions of Examples 18 to 23 of Table 3.

It can be seen that the room temperature specific resistance increases as the value of the composition ratio z of Ta of the first main component increases, but when the value of the composition ratio z of Ta exceeds 0.7 (Example 23), the room temperature dielectric constant decreases to less than 400. Problems arise.

That is, when the value of the composition ratio z of Ta is 0.7 or less (Examples 18 to 22), the room temperature specific resistance of the present invention is 1E11 Ohm-cm or more, high temperature 200 degree withstand voltage 50V/㎛ or more, TCC (150°C) ±15% or less , TCC(200℃) ±22% or less, and room temperature permittivity of 400 or more can be simultaneously implemented.

Even at this time, it can be seen that the area ratio of the second crystal grains to the total area falls within the range of 4.7% to 37.9%.

As described above, K and Ta of the first main component are in a complementary relationship. Therefore, it is possible to increase the room temperature dielectric constant to 800 or more while maintaining the room temperature specific resistance of 1E11 Ohm-cm or more by appropriately adjusting each composition ratio by simultaneously including K and Ta in the first main component.

Examples 24 to 30 in Table 5 are the base powder 0.9 (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ -0.1 BaTiO ₃ (y, z = 0.2): When the second sub-component MnO ₂ : 0.5 mol, the third sub-component SiO ₂ : 0.5 mol relative to 100 mol, examples according to the content of the first sub-component Li ₂ CO ₃ are shown, Table 6 Shows the characteristics of a prototype multilayer ceramic capacitor fired in a reducing atmosphere including a dielectric layer and a nickel (Ni) internal electrode prepared using the dielectric ceramic compositions of Examples 24 to 30 of Table 5.

When the content of the first subcomponent Li ₂ CO ₃ is less than 0.25 mol with respect to 100 mol of the base powder (Example 24), the problem of low room temperature specific resistance and high temperature withstand voltage is very low due to low sintering density, and the first sub component Li ₂ CO ₃ When the content of exceeds 5.0 mol with respect to 100 mol of the base powder (Example 30), there is a problem that the high temperature withstand voltage is lowered to less than 50 V/µm.

That is, when the content of the first subcomponent Li ₂ CO ₃ falls within the range of 0.25 mol to 5.0 mol with respect to 100 mol of the base powder (Examples 25 to 29), the room temperature specific resistance of the present invention is 1E11 Ohm-cm or more, and a high temperature of 200 degrees. Withstand voltage of 50V/㎛ or more, TCC(150℃) ±15% or less, TCC(200℃) ±22%, and room temperature dielectric constant 400 or more can be simultaneously implemented.

Even at this time, it can be seen that the area ratio of the second crystal grains to the total area falls within the range of 4.7% to 37.9%.

Examples 31 to 37 of Table 5 are the base powder 0.9 (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ -0.1 BaTiO ₃ (y, z = 0.2): When the first sub-component Li ₂ CO ₃ : 2.5 mol, and the third sub-component SiO ₂ : 0.5 mol relative to 100 mol, examples according to the content of the second sub-component MnO ₂ are shown, Table 6 Shows the characteristics of a prototype multilayer ceramic capacitor fired in a reducing atmosphere including a dielectric layer and a nickel (Ni) internal electrode prepared using the dielectric ceramic compositions of Examples 31 to 37 of Table 5.

When the content of the second sub-component MnO ₂ is less than 0.1 mol with respect to 100 mol of the base powder (Example 31), the problem of the room temperature specific resistance and high temperature withstand voltage is very low, and the content of the second sub-component MnO ₂ is in 100 mol of the base powder. On the other hand, there is a problem that the room temperature specific resistance and the high temperature withstand voltage are lowered even when the amount is excessive at the level of 5.0 mol (Example 37).

That is, when the content of the second subcomponent MnO ₂ falls within the range of 0.1 mol to 3.0 mol with respect to 100 mol of the base powder (Examples 32 to 36), the room temperature specific resistance of the present invention is 1E11 Ohm-cm or more, and the high temperature 200 degree withstand voltage 50 V /㎛ or more, TCC(150℃) less than ±15%, TCC(200℃) less than ±22%, and room temperature dielectric constant of 400 or more can be simultaneously implemented.

Even at this time, it can be seen that the area ratio of the second crystal grains to the total area falls within the range of 4.7% to 37.9%.

Examples 38 to 44 of Table 5 are the base powder 0.9 (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ -0.1 BaTiO ₃ (y, z = 0.2): When the first sub-component Li ₂ CO ₃ : 2.5 mol, and the second sub-component MnO ₂ : 0.5 mol relative to 100 mol, examples according to the content of the third sub-component SiO ₂ are shown, Table 6 Shows the characteristics of a prototype multilayer ceramic capacitor fired in a reducing atmosphere including a dielectric layer and a nickel (Ni) internal electrode prepared using the dielectric ceramic compositions of Examples 38 to 44 of Table 5.

When the content of the third subcomponent SiO ₂ is less than 0.1 mol with respect to 100 mol of the base powder (Example 38), the problem of low room temperature resistivity and high temperature withstand voltage is low due to low sintering density, and the content of the third sub component SiO ₂ is the base powder Even when there is an excessive amount of 7 mol relative to 100 mol (Example 44), there is a problem that the high temperature withstand voltage is lowered due to the generation of a secondary phase or the like.

That is, when the content of the third subcomponent SiO ₂ is 0.1 mol to 5.0 mol with respect to 100 mol of the base powder (Examples 39 to 43), the room temperature specific resistance of the present invention is 1E11 Ohm-cm or more, and the high temperature 200 degree withstand voltage 50 V/㎛ Above, it is possible to simultaneously implement all characteristics of TCC (150°C) less than ±15%, TCC (200°C) ±22%, and room temperature dielectric constant of 400 or more.

Even at this time, it can be seen that the area ratio of the second crystal grains to the total area falls within the range of 4.7% to 37.9%.

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is limited by the appended claims. Therefore, it will be apparent to those of ordinary skill in the art that various types of substitutions, modifications and changes are possible within the scope of the technical spirit of the present invention described in the claims, and the appended claims It will be said to belong to the technical idea described in.

100: multilayer ceramic capacitor 110: ceramic body
111: dielectric layers 121, 122: first and second internal electrodes
131, 132: first and second external electrodes

Claims (9)

Including a base material powder and sub-components containing a first main component and a second main component,
The first main component is (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ , and the second main component is BaTiO ₃ ,
When the base powder is (1-x) (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ -x BaTiO ₃ ,
The x is 0.05 ≤ x ≤ 0.4,
Where y is 0.1 ≤ y ≤ 0.7,
Wherein z is 0.1≦z≦0.7. delete The method of claim 1,
The subcomponent includes a first subcomponent,
When the first sub-component is included, the first sub-component contains any one or more selected from oxides or carbonates containing Li,
The dielectric ceramic composition in which the content of the first subcomponent is 0.5 mol to 10.0 mol of the Li element with respect to 100 mol of the base material powder. The method of claim 1,
The subcomponent includes a second subcomponent,
The second subcomponent includes at least one selected from the group consisting of oxides or carbonates of variable valence acceptor elements of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn,
The content of the second subcomponent is a dielectric ceramic composition in which the content of the variable valence acceptor element included in the second subcomponent is 0.1 mol to 3.0 mol with respect to 100 mol of the base powder. The method of claim 1,
The subcomponent includes a third subcomponent,
Including at least one selected from the group consisting of an oxide of the Si element, a carbonate of the Si element, and a glass containing the Si element,
The content of the third subcomponent is a dielectric ceramic composition in which the content of the Si element is 0.1 mol to 5.0 mol with respect to 100 mol of the base material powder. A ceramic body including a dielectric layer and an internal electrode; And
Including; an external electrode disposed on the outside of the ceramic body and connected to the internal electrode,
The dielectric layer includes first grains and second grains,
The first grains are grains having a Ba content of less than 10 at% and a Ti content of less than 10 at%, and the second grains are grains having a Ba content of 10 at% or more and a Ti content of 10 at% or more,
The area ratio of the second crystal grains to the total area is 4.7% to 37.9%,
The dielectric layer includes a base material powder and a subcomponent including a first main component and a second main component,
The first main component is (K _y Na _1-y ) (Nb _1-z Ta _z ) O ₃ , and the second main component is BaTiO ₃ ,
When the base powder is (1-x) (K _y Na _1-y )(Nb _1-z Ta _z )O ₃ -x BaTiO ₃ ,
The x is 0.05 ≤ x ≤ 0.4,
Where y is 0.1 ≤ y ≤ 0.7,
The multilayer ceramic capacitor in which z is 0 <z ≤ 0.7. delete The method of claim 6,
The internal electrode is a multilayer ceramic capacitor containing nickel (Ni). The method of claim 6,
Room temperature resistivity of 1E11 Ohm-cm or more;
High temperature 200 degree withstand voltage 50V/µm or more;
Less than TCC (150° C.)±15%;
Less than TCC (200° C.)±22%; And
A multilayer ceramic capacitor that satisfies the room temperature dielectric constant of 800 or more.

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