Dielectric ceramic composition and multilayer ceramic capacitor including the same

Abstract

To provide a dielectric ceramic composition capable of improving reliability, and to provide a multilayer ceramic capacitor comprising the same.SOLUTION: A dielectric ceramic composition according to one embodiment of this invention includes a BaTiO3-based base material main ingredient and an accessory ingredient, wherein: the accessory ingredient includes a trivalent lanthanide rare earth element A and terbium (Tb) as rare earth elements; and a ratio (Tb / A) of a content of terbium (Tb) to the content of the trivalent lanthanide rare earth element A satisfies 0.15≤Tb / A<0.50. A multilayer ceramic capacitor comprising the same is also provided.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a dielectric ceramic composition capable of improving reliability and a multilayer ceramic capacitor including the same. [Background technology]

[0002] In general, electronic components using ceramic materials, such as capacitors, inductors, piezoelectric elements, varistors, or thermistors, comprise a ceramic body made of a ceramic material, an internal electrode formed inside the body, and an external electrode arranged on the surface of the ceramic body so as to be connected to the internal electrode.

[0003] Recently, as electronic products become smaller and more multifunctional, chip components are also becoming smaller and more functional. This has created a demand for multilayer ceramic capacitors that are small in size and have a large capacitance.

[0004] One way to achieve both miniaturization and high capacitance in multilayer ceramic capacitors is to reduce the thickness of the internal dielectric layers and electrode layers and stack a large number of them. Currently, the thickness of the dielectric layer is about 0.6 μm, and development is ongoing to make it thinner.

[0005] Under these circumstances, ensuring the reliability of the dielectric layer has become an important issue for dielectric materials. At the same time, the rate of defects is increasing due to the deterioration of the insulation resistance of the dielectric, making it difficult to control the quality and yield.

[0006] In order to solve these problems, a new method is required that can ensure high reliability not only in terms of the structure of the multilayer ceramic capacitor, but also in terms of the dielectric composition in particular.

[0007] If a dielectric composition capable of raising the reliability level one step further from the current level could be secured, it would be possible to manufacture multilayer ceramic capacitors with even thinner layers. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a dielectric ceramic composition capable of improving reliability and a multilayer ceramic capacitor including the same. [Means for solving the problem]

[0009] One embodiment of the present invention provides a dielectric ceramic composition comprising a BaTiO3-based matrix main component and an auxiliary component, the auxiliary component including a trivalent lanthanum group rare earth element A and terbium (Tb) as rare earth elements, and a ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50.

[0010] Another embodiment of the present invention provides a multilayer ceramic capacitor including: a ceramic body including a dielectric layer, and a first internal electrode and a second internal electrode arranged to face each other with the dielectric layer therebetween; a first external electrode arranged on an outside of the ceramic body and electrically connected to the first internal electrode, and a second external electrode electrically connected to the second internal electrode, wherein the dielectric layer includes a dielectric ceramic composition, the dielectric ceramic composition includes a BaTiO3-based matrix main component and an auxiliary component, the auxiliary component includes a trivalent lanthanum group rare earth element A and terbium (Tb) as rare earth elements, and a ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50. Effect of the Invention

[0011] According to one embodiment of the present invention, the dielectric ceramic composition contained in the dielectric layer in the ceramic body contains terbium (Tb), a new rare earth element, as an auxiliary component, and by controlling the content of terbium (Tb), it is possible to improve reliability, such as improving insulation resistance. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic perspective view showing a multilayer ceramic capacitor according to an embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view taken along line II' in FIG. [Diagram 3] 1 is a graph showing evaluation results of a reliability test (HALT) performed under severe conditions according to an embodiment of the present invention and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 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 into various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those having average knowledge in the art. Therefore, the shapes and sizes of elements in the drawings may be enlarged or reduced (or highlighted or simplified) for clearer explanation, and elements indicated by the same reference numerals in the drawings are the same elements.

[0014] FIG. 1 is a schematic perspective view showing a multilayer ceramic capacitor according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II' of FIG.

[0015] 1 and 2, a multilayer ceramic capacitor 100 according to an embodiment of the present invention includes a ceramic body 110 including a dielectric layer 111, a first internal electrode 121 and a second internal electrode 122 arranged to face each other with the dielectric layer 111 in between, a first external electrode 131 arranged on the outside of the ceramic body 110 and electrically connected to the first internal electrode 121, and a second external electrode 132 electrically connected to the second internal electrode 122.

[0016] In the multilayer ceramic capacitor 100 according to an embodiment of the present invention, the "length direction" is defined as the "L" direction in Fig. 1, the "width direction" is defined as the "W" direction, and the "thickness direction" is defined as the "T" direction. Here, the "thickness direction" can be used in the same concept as the direction in which the dielectric layers are stacked, i.e., the "stacking direction".

[0017] The shape of the ceramic body 110 is not particularly limited, but may be a hexahedron as shown in the drawing.

[0018] A plurality of internal electrodes 121 and 122 formed inside the ceramic body 110 have one end exposed to one surface of the ceramic body or the other surface opposite to the one surface.

[0019] The internal electrodes 121 and 122 may be paired with a first internal electrode 121 and a second internal electrode 122 having different polarities.

[0020] One end of the first internal electrode 121 may be exposed to one surface of the ceramic body, and one end of the second internal electrode 122 may be exposed to the other surface opposite the one surface.

[0021] First and second external electrodes 131 and 132 may be formed on one surface and the other surface facing the one surface of the ceramic body 110 and may be electrically connected to the internal electrodes.

[0022] The material for forming the first and second internal electrodes 121, 122 is not particularly limited, and the first and second internal electrodes 121, 122 may be formed using a conductive paste containing one or more of silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), and copper (Cu), for example.

[0023] The first and second external electrodes 131, 132 may be electrically connected to the first and second internal electrodes 121, 122 to form a capacitance, and the second external electrode 132 may be connected to a different potential than the first external electrode 131.

[0024] The conductive material contained in the first and second external electrodes 131, 132 is not particularly limited, but may be nickel (Ni), copper (Cu), or an alloy thereof.

[0025] The thickness of the first and second external electrodes 131, 132 can be appropriately determined depending on the application and is not particularly limited, and may be, for example, 10 to 50 μm.

[0026] According to one embodiment of the present invention, the raw material for forming the dielectric layer 111 is not particularly limited as long as it can obtain a sufficient capacitance, and may be, for example, barium titanate (BaTiO3) powder.

[0027] The material forming the dielectric layer 111 may be a powder of barium titanate (BaTiO3) or the like to which various additives, organic solvents, plasticizers, binders, dispersants, etc. may be added according to the purpose of the present invention.

[0028] The dielectric layers 111 are in a sintered state, and may be integrated to such an extent that the boundaries between adjacent dielectric layers cannot be recognized.

[0029] First and second internal electrodes 121 and 122 may be formed on the dielectric layer 111, and the internal electrodes 121 and 122 may be formed inside the ceramic body by sintering with one dielectric layer sandwiched therebetween.

[0030] The thickness of the dielectric layer 111 can be changed as desired depending on the capacitance design of the capacitor. In one embodiment of the present invention, the thickness of the dielectric layer after firing may preferably be 0.45 μm or less per layer.

[0031] Moreover, the thickness of the first and second internal electrodes 121, 122 after firing may preferably be 0.45 μm or less per layer.

[0032] According to an embodiment of the present invention, the dielectric layer 111 includes a BaTiO3-based matrix main component and an auxiliary component, and the auxiliary component includes a dielectric ceramic composition including a trivalent lanthanum group rare earth element A and terbium (Tb) as rare earth elements, and the ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50.

[0033] In particular, the trivalent lanthanum group rare earth element A can be dysprosium (Dy).

[0034] According to one embodiment of the present invention, the ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50.

[0035] When the ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50, the effect of improving reliability, such as improving insulation resistance, is excellent.

[0036] In particular, the trivalent lanthanum group rare earth element A can be dysprosium (Dy), and when the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content satisfies 0.15≦Tb / Dy<0.50, the effect of improving reliability, such as improving insulation resistance, is excellent.

[0037] According to one embodiment of the present invention, the dielectric ceramic composition contained in the dielectric layer in the ceramic body contains a trivalent lanthanum group rare earth element A and a rare earth element terbium (Tb) as minor components, and by controlling the content ratio of the rare earth element terbium (Tb) to the trivalent lanthanum group rare earth element A, it is possible to improve reliability such as improving insulation resistance.

[0038] When the ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A is less than 0.15, the effect of improving reliability by adding terbium (Tb) is small, and when the ratio of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A is 0, that is, when terbium (Tb) is not added as in the conventional case, there is no effect of improving reliability and the failure rate may increase.

[0039] Furthermore, if the ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A is 0.50 or more, a decrease in insulation resistance due to semiconductivity may occur.

[0040] The trivalent lanthanum group rare earth element A can be dysprosium (Dy). When the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content is less than 0.15, the effect of improving reliability by adding terbium (Tb) is small. When the ratio of the terbium (Tb) content to the dysprosium (Dy) content is 0, that is, when terbium (Tb) is not added as in the conventional case, there is no effect of improving reliability and the failure rate may increase.

[0041] Furthermore, if the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content is 0.50 or more, a decrease in insulation resistance due to semiconductivity may occur.

[0042] According to one embodiment of the present invention, the total content of the trivalent lanthanum group rare earth element A and terbium (Tb) may be 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) in the main component of the matrix.

[0043] In particular, the trivalent lanthanum group rare earth element A can be dysprosium (Dy).

[0044] Generally, a large amount of rare earth elements are added to ensure the reliability of the dielectric inside the multilayer ceramic capacitor.

[0045] Among these rare earth elements, dysprosium (Dy) is known to be effective in improving reliability by replacing Ba-site and reducing the concentration of oxygen vacancy defects when added to barium titanate (BaTiO3), which is the main component of the base material.

[0046] On the other hand, when rare earth elements with a larger ionic radius than dysprosium (Dy), such as lanthanum (La) or samarium (Sm), are used, Ba-site can be substituted more effectively, and therefore the concentration of oxygen vacancy defects can be reduced more effectively. However, excessive semiconductivity causes a rapid drop in insulation resistance, and this has not yet reached a practical level.

[0047] Therefore, in order to minimize the concentration of oxygen vacancy defects to improve reliability, and to suppress semiconductor formation to ensure insulation resistance, it was considered best to use a rare earth element whose ionic radius is larger than that of dysprosium (Dy), but whose size difference with that of Dy is not large.

[0048] In addition, the valence of the general rare earth elements is +3, so when substituting Ba(+2), one positive charge (D · Ba ), but in the case of terbium (Tb), which can have a variable valence of +4, it is called a double positive charge (D ·· Ba ), the effect of reducing the concentration of oxygen vacancies can be doubled.

[0049] In contrast, when it comes to an element with a variable valence of +2, such as ytterbium (Yb), it is not effective in reducing the concentration of oxygen vacancy defects when substituting Ba(+2) because it is charge-neutral. For this reason, it is known that adding ytterbium (Yb) actually further deteriorates reliability.

[0050] Therefore, although it has a larger ionic radius than dysprosium (Dy), terbium (Tb) element, which has multiple atomization and does not progress to semiconductivity to the extent that it reduces insulation resistance, is most effective in reducing the concentration of oxygen vacancy defects, and is therefore expected to significantly improve the reliability of the dielectric in multilayer ceramic capacitors. As a result, a dielectric ceramic composition that uses both dysprosium (Dy) and terbium (Tb) was developed.

[0051] Conventionally, there have been attempts to add one or more of dysprosium (Dy), gadolinium (Gd), and terbium (Tb) as rare earth elements to a dielectric ceramic composition.

[0052] However, in the above-mentioned conventional cases, the above-mentioned effects of terbium (Tb) were not recognized, and terbium (Tb) was merely described as a rare earth element or added in small amounts, and no specific research was conducted on the amount of terbium (Tb) added to improve reliability.

[0053] On the other hand, in one embodiment of the present invention, an optimum ratio of the amounts of dysprosium (Dy) and terbium (Tb) added that is highly effective in improving reliability has been found.

[0054] According to one embodiment of the present invention, the total content of the trivalent lanthanum group rare earth element A and terbium (Tb) is adjusted to 0.2 to 1.5 moles per 100 moles of titanium (Ti) in the main component of the base material, thereby making it possible to improve reliability, such as improving insulation resistance.

[0055] When the trivalent lanthanum group rare earth element A is dysprosium (Dy), the total content of the dysprosium (Dy) and terbium (Tb) is 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) among the main components of the base material.

[0056] By adjusting the total content of dysprosium (Dy) and terbium (Tb) to be 0.2 moles or more and 1.5 moles or less per 100 moles of titanium (Ti), which is the main component of the base material, it is possible to improve reliability, such as by improving insulation resistance.

[0057] The higher the total content of rare earth elements, the more advantageous it is in terms of reliability. However, as Tc moves to room temperature, the temperature characteristics are significantly reduced. Therefore, it is preferable to adjust the total content of dysprosium (Dy) and terbium (Tb) to 1.5 mol or less per 100 mol of titanium (Ti), which is the main component of the base material.

[0058] If the total content of dysprosium (Dy) and terbium (Tb) exceeds 1.5 moles per 100 moles of titanium (Ti) among the main components of the base material, there is a possibility that temperature characteristics such as the temperature coefficient of capacitance (TCC) may decrease.

[0059] On the other hand, when the total content of dysprosium (Dy) and terbium (Tb) is less than 0.2 moles per 100 moles of titanium (Ti) among the main components of the base material, the reliability may decrease.

[0060] As described above, the multilayer ceramic capacitor 100 according to an embodiment of the present invention is an ultra-compact, high-capacity product, and is characterized in that the thickness of the dielectric layer 111 is 0.45 μm or less and the thickness of the first and second internal electrodes 121, 122 is 0.45 μm or less, but is not necessarily limited thereto.

[0061] That is, since the multilayer ceramic capacitor 100 according to an embodiment of the present invention is an ultra-compact, high-capacity product, the dielectric layer 111 and the first and second internal electrodes 121, 122 are configured to be thinner than those of conventional products. In the case of products to which such thin dielectric layers and internal electrodes are applied, research into improving reliability, such as insulation resistance, is a very important issue.

[0062] That is, in the case of the conventional multilayer ceramic capacitor, since the dielectric layers and the internal electrodes are relatively thicker than those included in the multilayer ceramic capacitor according to the embodiment of the present invention, even if the composition of the dielectric ceramic composition is the same as that of the conventional one, there has been no significant problem in reliability.

[0063] However, in a product in which a thin dielectric layer and an internal electrode are applied, such as in one embodiment of the present invention, the reliability of the multilayer ceramic capacitor is important, and therefore it is necessary to adjust the composition of the dielectric ceramic composition.

[0064] That is, in one embodiment of the present invention, the total content of the trivalent lanthanum group rare earth element A and terbium (Tb) is adjusted to be 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) among the main components of the base material, and in particular, the ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A is adjusted to satisfy 0.15≦Tb / A<0.50, thereby making it possible to improve reliability, such as improving insulation resistance, even when the dielectric layer 111 and the first and second internal electrodes 121, 122 are thin films having a thickness of 0.45 μm or less.

[0065] However, the above-mentioned thin film does not mean that the thickness of the dielectric layer 111 and the first and second internal electrodes 121, 122 is 0.45 μm or less, but should be understood as a concept including dielectric layers and internal electrodes that are thinner than those of conventional products.

[0066] Hereinafter, each component of the dielectric ceramic composition according to one embodiment of the present invention will be described in more detail.

[0067] a) Base material main component The dielectric ceramic composition according to an embodiment of the present invention can include a base material main component represented by BaTiO3.

[0068] According to an embodiment of the present invention, the above base material main component is BaTiO3, (Ba 1-x Ca x )(Ti 1-y Ca y )O3 (where x is 0≤x≤0.3 and y is 0≤y≤0.1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (where x is 0≤x≤0.3 and y is 0≤y≤0.5), and Ba(Ti 1-y Zr y )O3 (where 0 < y≤0.5), and includes one or more selected from the group consisting of, but is not necessarily limited thereto.

[0069] The dielectric ceramic composition according to an embodiment of the present invention can have a room temperature dielectric constant of 2000 or more.

[0070] The above base material main component is not particularly limited, but the average particle size of the main component powder may be 40 nm or more and 150 nm or less.

[0071] b) First sub-component According to an embodiment of the present invention, the above dielectric ceramic composition necessarily contains dysprosium (Dy) and terbium (Tb) as the first sub-component elements, and further contains 0.0 to 4.0 moles of a first sub-component which is an oxide or carbonate containing at least one of Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, and Sm with respect to 100 moles of the above base material main component.

[0072] In an embodiment of the present invention, the above first sub-component plays a role in preventing a decrease in the reliability of a multilayer ceramic capacitor to which the dielectric ceramic composition is applied.

[0073] If the content of the first subcomponent exceeds 4.0 moles, problems may occur such as a decrease in reliability or a decrease in the dielectric constant of the dielectric ceramic composition, resulting in poor high-temperature voltage resistance characteristics.

[0074] According to one embodiment of the present invention, the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content satisfies 0.15≦Tb / Dy<0.50.

[0075] By adjusting the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content so as to satisfy 0.15≦Tb / Dy<0.50, it is possible to improve reliability, such as by improving insulation resistance.

[0076] When the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content is less than 0.15, the effect of improving reliability by adding terbium (Tb) is small, and when the ratio of the terbium (Tb) content to the dysprosium (Dy) content is 0, that is, when terbium (Tb) is not added as in the conventional case, there is no effect of improving reliability and the failure rate may increase.

[0077] On the other hand, if the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content is 0.50 or more, a decrease in insulation resistance due to semiconductivity may occur.

[0078] The total content of dysprosium (Dy) and terbium (Tb) is 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) in the main component of the base material.

[0079] By adjusting the total content of dysprosium (Dy) and terbium (Tb) to be 0.2 moles or more and 1.5 moles or less per 100 moles of titanium (Ti), which is the main component of the base material, it is possible to improve reliability, such as by improving insulation resistance.

[0080] c) Second subcomponent According to an embodiment of the present invention, the dielectric ceramic composition may include, as a second subcomponent, an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn.

[0081] As the second subcomponent, an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn may be contained in an amount of 0.1 to 2.0 mol per 100 mol of the base powder.

[0082] The second subcomponent serves to lower the firing temperature of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied, and to improve the high-temperature withstand voltage characteristics.

[0083] The content of the second subcomponent and the contents of the third to sixth subcomponents described below refer to the amounts contained per 100 moles of the base powder, and can be specifically defined as the moles of metal ions contained in each subcomponent.

[0084] If the content of the second subcomponent is less than 0.1 mol, the firing temperature becomes high and the high-temperature voltage resistance characteristics may be slightly deteriorated.

[0085] Furthermore, if the content of the second subcomponent is 2.0 moles or more, the high-temperature withstand voltage characteristics and room-temperature resistivity may decrease.

[0086] In particular, the dielectric ceramic composition according to one embodiment of the present invention may contain a second subcomponent having a content of 0.1 to 2.0 mol per 100 mol of the main matrix component, which allows low-temperature firing and high high-temperature withstand voltage characteristics.

[0087] d) Third subcomponent According to an embodiment of the present invention, the dielectric ceramic composition may include a third subcomponent which is an oxide or carbonate containing Mg, which is a fixed-valence acceptor element.

[0088] The fixed-valence acceptor element Mg may contain 0.0 to 0.5 mol of a third subcomponent per 100 mol of titanium (Ti) among the main components of the matrix.

[0089] The third minor component is a fixed-valence acceptor or a compound containing the same, and acts as an acceptor to reduce the concentration of electrons. By adding 0.0 to 0.5 mol of Mg, the fixed-valence acceptor element of the third minor component, to 100 mol of titanium (Ti) of the main component of the matrix, the reliability improvement effect due to n-type can be maximized.

[0090] If the content of the third subcomponent exceeds 0.5 mol per 100 mol of the base powder, the dielectric constant becomes low, which is undesirable.

[0091] However, according to one embodiment of the present invention, it is preferable to add 0.5 moles of the third subcomponent to 100 moles of titanium (Ti) in order to maximize the effect of improving reliability by making the material n-type; however, this is not necessarily limited to this amount, and the third subcomponent may be added in an amount of 0.5 moles or less or slightly more than 0.5 moles.

[0092] e) Fourth subcomponent According to one embodiment of the present invention, the dielectric ceramic composition may include a fourth subcomponent which is an oxide or carbonate containing Ba.

[0093] The dielectric ceramic composition may contain 0.0 to 4.15 mol of a fourth subcomponent which is an oxide or carbonate containing Ba, relative to 100 mol of the base material main component.

[0094] The content of the fourth minor component can be based on the content of Ba element contained in the fourth minor component, regardless of the added form such as oxide or carbonate.

[0095] The fourth subcomponent can play a role of promoting sintering in the dielectric ceramic composition and adjusting the dielectric constant, and if the content of the fourth subcomponent exceeds 4.15 mol with respect to 100 mol of the main component of the matrix, there may be a problem that the dielectric constant becomes low or the firing temperature becomes high.

[0096] f) Fifth subcomponent According to an embodiment of the present invention, the dielectric ceramic composition may include a fifth subcomponent including at least one selected from the group consisting of oxides and carbonates of at least one element of Ca and Zr.

[0097] The dielectric ceramic composition may contain 0.0 to 20.0 mol of a fifth subcomponent which is an oxide or carbonate containing at least one of Ca and Zr, relative to 100 mol of the base material main component.

[0098] The content of the fifth minor component may be based on the content of at least one of Ca and Zr contained in the fifth minor component, regardless of the added form such as oxide or carbonate.

[0099] The fifth subcomponent plays a role in improving the dielectric constant and reliability by forming a core-shell structure in the dielectric ceramic composition. When the fifth subcomponent is contained in an amount of 20.0 mol or less relative to 100 mol of the main matrix component, a high dielectric constant is realized, and a dielectric ceramic composition having good high-temperature withstand voltage characteristics can be provided.

[0100] If the content of the fifth subcomponent exceeds 20.0 moles per 100 moles of the main component of the base material, the room temperature dielectric constant decreases and the high temperature withstand voltage characteristics also decrease.

[0101] g) 6th subcomponent According to an embodiment of the present invention, the dielectric ceramic composition may include, as a sixth subcomponent, an oxide containing at least one of Si and Al, or a glass compound containing Si.

[0102] The dielectric ceramic composition may further contain 0.0 to 4.0 mol of a sixth subcomponent which is an oxide containing at least one of Si and Al or a glass compound containing Si, relative to 100 mol of the matrix main component.

[0103] The content of the sixth minor component may be based on the content of at least one of Si and Al contained in the sixth minor component, regardless of the added form such as glass, oxide, or carbonate.

[0104] The sixth subcomponent plays a role in lowering the firing temperature of the multilayer ceramic capacitor to which the dielectric ceramic composition is applied, and improving the high-temperature withstand voltage characteristics.

[0105] If the content of the sixth subcomponent exceeds 4.0 moles per 100 moles of the main component of the matrix, it is not preferable because it reduces sinterability and density and causes problems such as the generation of secondary phases.

[0106] In particular, according to one embodiment of the present invention, the dielectric ceramic composition contains Al in an amount of 4.0 mol or less, which makes it possible to uniformly control grain growth, and is effective in improving voltage resistance characteristics and reliability, and also improves DC-bias characteristics.

[0107] The present invention will be described in more detail below with reference to examples and comparative examples. However, these are intended to aid in the specific understanding of the invention, and the scope of the present invention is not limited to these examples. EXAMPLES

[0108] (Example) In an embodiment of the present invention, additives such as Dy, Tb, Al, Mg, Mn, etc., binders, and organic solvents such as ethanol are added to a dielectric raw material powder including barium titanate (BaTiO3) powder, and the mixture is wet mixed to prepare a dielectric slurry, and then the dielectric slurry is applied onto a carrier film and dried to provide a ceramic green sheet, thereby forming a dielectric layer.

[0109] At this time, the additive elements were added in a monodispersed state so that the size ratio of all the additive elements was 40% or less relative to the barium titanate.

[0110] In particular, the content of dysprosium (Dy) and terbium (Tb) among the added rare earth elements was set to 1.5 moles per 100 moles of titanium (Ti) among the main components of the base material.

[0111] Of the above examples, Example 1 was produced by adding 1.5 moles of dysprosium (Dy) and terbium (Tb) to 100 moles of titanium (Ti) among the main components of the base material, and Example 2 was produced by adjusting the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content to be 0.15 or more and less than 0.5.

[0112] The ceramic green sheet can be produced by mixing ceramic powder, a binder, and a solvent to prepare a slurry, and then forming the slurry into a sheet having a thickness of several μm using a doctor blade method.

[0113] Next, a conductive paste for the internal electrodes containing 40 to 50 parts by weight of nickel powder having an average particle size of 0.1 to 0.2 μm can be provided.

[0114] The conductive paste for the internal electrodes was applied onto the green sheets by a screen printing method to form internal electrodes, and the green sheets on which the internal electrode patterns were arranged were laminated to form a laminate, and then the laminate was compressed and cut.

[0115] The cut laminate was then heated to remove the binder and then fired at high temperature in a reducing atmosphere to form the ceramic body.

[0116] In the above firing process, the material was fired in a reducing atmosphere (0.1% H2 / 99.9% N2, H2O / H2 / N2 atmosphere) at a temperature of 1100 to 1200°C for 2 hours, and then oxidized and heat-treated in a nitrogen (N2) atmosphere at 1000°C for 3 hours.

[0117] Next, the fired ceramic body was subjected to a termination process using copper (Cu) paste and then fired to form external electrodes.

[0118] Moreover, the dielectric layer 111 and the first and second internal electrodes 121, 122 inside the ceramic body 110 were manufactured so as to have a thickness of 0.45 μm or less after firing.

[0119] Comparative Example 1 In Comparative Example 1, dysprosium (Dy) and terbium (Tb) were added so that the total content was 1.8 moles per 100 moles of titanium (Ti), which is the main component of the base material, and the other manufacturing processes were the same as those of the above-mentioned examples.

[0120] Comparative Example 2 In Comparative Example 2, dysprosium (Dy) and terbium (Tb) were added so that the total content was 2.1 moles per 100 moles of titanium (Ti), which is the main component of the base material, and the other manufacturing processes were the same as those of the above-mentioned examples.

[0121] Comparative Example 3 Comparative Example 3 is a conventional dielectric ceramic composition, which does not contain terbium (Tb) and contains only dysprosium (Dy). The other manufacturing processes are the same as those of the above-mentioned examples.

[0122] Comparative Example 4 In Comparative Example 4, the terbium (Tb) content was added so that the ratio (Tb / Dy) of the dysprosium (Dy) content to the terbium (Tb) content was less than 0.15, and the other manufacturing processes were the same as those of the above-mentioned examples.

[0123] Comparative Example 5 In the case of Comparative Example 5, the terbium (Tb) content was added so that the ratio (Tb / Dy) of the dysprosium (Dy) content to the terbium (Tb) content was 0.5 or more, and the other manufacturing processes were the same as those of the above-mentioned examples.

[0124] The prototype MLCC samples of Examples 1 and 2 and Comparative Examples 1 to 5 were subjected to a temperature characteristic test and a HALT test to evaluate the failure rate.

[0125] The temperature characteristic test was conducted to measure the Temperature Coefficient of Capacitance (TCC). The X5R temperature characteristic must satisfy a capacitance of ±15% in the range of -55°C to 85°C based on a capacitance of 25°C, and the X6S temperature characteristic must satisfy a capacitance of ±22% in the range of -55°C to 105°C based on a capacitance of 25°C.

[0126] In the HALT test, 40 multilayer ceramic capacitor (MLCC) chips were mounted on a substrate for each sample, and measurements were performed for 12 hours under conditions of 125°C and 20V (DC).

[0127] The following Table 1 shows the above-mentioned electrical characteristics of the prototype multilayer ceramic capacitor (prototype MLCC) chips according to the experimental examples (Examples 1 and 2 and Comparative Examples 1 and 2).

[0128] [Table 1]

[0129] Referring to Table 1 above, it can be seen that in Comparative Example 1 and Comparative Example 2, in which the total content of dysprosium (Dy) and terbium (Tb) exceeds 1.5 mol per 100 mol of titanium (Ti) among the main components of the base material, not only the X6S temperature characteristics but also the X5R temperature characteristics are not satisfied.

[0130] In contrast, in Example 1 of the present invention, the total content of dysprosium (Dy) and terbium (Tb) is 1.5 moles or less per 100 moles of titanium (Ti) among the main components of the base material, and it can be confirmed that not only the X6S temperature characteristics but also the X5R temperature characteristics are satisfied, and that excellent improvement in reliability is also achieved.

[0131] FIG. 3 is a graph showing the evaluation results of the HALT test according to the examples of the present invention and the comparative examples.

[0132] 3, in the case of Comparative Example 3 (a) of the present invention, the composition is the same as that of the conventional dielectric ceramic composition, but terbium (Tb) is not added and only dysprosium (Dy) is added. Here, it can be seen that the number of defective pieces after the HALT test was 5, which is a high defective rate.

[0133] In the case of Comparative Example 4 (b) of the present invention, the terbium (Tb) content was added so that the ratio (Tb / Dy) of the dysprosium (Dy) content to the terbium (Tb) content was less than 0.15, and it can be seen that the number of defective pieces after the HALT test was 9, which was a high defect rate.

[0134] This is believed to be due to the fact that the content of the terbium (Tb) added is small relative to the content of the dysprosium (Dy), and the effect of improving reliability by adding terbium (Tb) is small.

[0135] In contrast, in the case of Example 2 of the present invention (c), where the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content is equal to or greater than 0.15 and less than 0.5, it can be confirmed that the number of defective pieces after the HALT test is 0, which is an excellent improvement in reliability.

[0136] On the other hand, in the case of Comparative Example 5 of the present invention (d), in which the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content was 0.5 or more, almost all samples were found to have poor reliability.

[0137] When the ratio (Tb / Dy) of the terbium (Tb) content to the dysprosium (Dy) content is 0.50 or more, it is believed that a decrease in insulation resistance occurs due to semiconductivity.

[0138] Although the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that the scope of the present invention is not limited thereto, and that various modifications and variations are possible within the scope of the technical idea of ​​the present invention described in the claims.

[0139] [Item 1] Contains BaTiO3-based base material main component and sub-components, The auxiliary component contains a trivalent lanthanum group rare earth element A and terbium (Tb) as rare earth elements, A dielectric ceramic composition, wherein a ratio (Tb / A) of the content of said terbium (Tb) to the content of said trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50. [Item 2] 2. The dielectric ceramic composition according to item 1, wherein the trivalent lanthanum group rare earth element A is dysprosium (Dy). [Item 3] 3. The dielectric ceramic composition according to item 1 or 2, wherein the total content of the trivalent lanthanum group rare earth element A and terbium (Tb) is 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) in the main component of the matrix. [Item 4] The dielectric ceramic composition according to any one of items 1 to 3, further comprising 0.0 to 4.0 mol of a first auxiliary component which is an oxide or carbonate containing at least one of Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, and Sm, relative to 100 mol of the base material main component. [Item 5] The dielectric ceramic composition according to any one of items 1 to 4, further comprising 0.1 to 2.0 mol of a second auxiliary component which is an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn, relative to 100 mol of the base material main component. [Item 6] The dielectric ceramic composition according to any one of items 1 to 5, further comprising 0.0 to 0.5 mol of a third subcomponent which is an oxide or carbonate containing Mg as a fixed valence acceptor element per 100 mol of titanium (Ti) in the matrix main component. [Item 7] The dielectric ceramic composition according to any one of items 1 to 6, further comprising 0.0 to 4.15 mol of a fourth subcomponent which is an oxide or carbonate containing Ba, relative to 100 mol of the base material main component. [Item 8] The dielectric ceramic composition according to any one of items 1 to 7, wherein the dielectric ceramic composition contains 0.0 to 20.0 mol of a fifth subcomponent which is an oxide or carbonate containing at least one of Ca and Zr, relative to 100 mol of the base material main component. [Item 9] The dielectric ceramic composition according to any one of items 1 to 8, further comprising 0.0 to 4.0 mol of a sixth subcomponent which is an oxide containing at least one of Si and Al or a glass compound containing Si, relative to 100 mol of the base material main component. [Item 10] a ceramic body including a dielectric layer, and a first internal electrode and a second internal electrode disposed opposite each other with the dielectric layer interposed therebetween; a first external electrode disposed outside the ceramic body and electrically connected to the first internal electrode, and a second external electrode electrically connected to the second internal electrode, the dielectric layer comprises a dielectric ceramic composition; The dielectric ceramic composition contains a BaTiO3-based matrix main component and a subcomponent, The auxiliary component contains a trivalent lanthanum group rare earth element A and terbium (Tb) as rare earth elements, A multilayer ceramic capacitor, wherein a ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50. [Item 11] Item 11. The multilayer ceramic capacitor according to item 10, wherein the trivalent lanthanum group rare earth element A is dysprosium (Dy). [Item 12] Item 12. The multilayer ceramic capacitor according to item 10 or 11, wherein the total content of the trivalent lanthanum group rare earth element A and terbium (Tb) is 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) in the main component of the base material. [Item 13] 13. The multilayer ceramic capacitor according to any one of items 10 to 12, wherein the dielectric ceramic composition further contains 0.0 to 4.0 mol of a first subcomponent which is an oxide or carbonate containing at least one of Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, and Sm, relative to 100 mol of the base material main component. [Item 14] Item 14. The multilayer ceramic capacitor according to any one of items 10 to 13, wherein the dielectric ceramic composition further contains 0.1 to 2.0 mol of a second auxiliary component which is an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn, relative to 100 mol of the base material main component. [Item 15] 15. The multilayer ceramic capacitor according to any one of items 10 to 14, wherein the dielectric ceramic composition further contains 0.0 to 0.5 mol of a third subcomponent which is an oxide or carbonate containing Mg as a fixed valence acceptor element per 100 mol of titanium (Ti) in the base material main component. [Item 16] 16. The multilayer ceramic capacitor according to any one of items 10 to 15, wherein the dielectric ceramic composition further contains 0.0 to 4.15 mol of a fourth subcomponent which is an oxide or carbonate containing Ba, and 0.0 to 20.0 mol of a fifth subcomponent which is an oxide or carbonate containing at least one of Ca and Zr, relative to 100 mol of the base material main component. [Item 17] 17. The multilayer ceramic capacitor according to any one of items 10 to 16, wherein the dielectric ceramic composition further contains 0.0 to 4.0 mol of a sixth subcomponent which is an oxide containing at least one of Si and Al or a glass compound containing Si, relative to 100 mol of the base material main component. [Item 18] Item 18. The multilayer ceramic capacitor according to any one of items 10 to 17, wherein the dielectric layers have a thickness of 0.45 μm or less, and the first and second internal electrodes have a thickness of 0.45 μm or less. [Explanation of symbols]

[0140] 110 Ceramic body 111 Dielectric layer 121 1st internal electrode 122 2nd internal electrode 131 1st external electrode 132 2nd external electrode

Claims

1. BaTiO ３ Contains the main and secondary components of the base material. The auxiliary component contains a trivalent lanthanum group rare earth element A and terbium (Tb) as rare earth elements, a ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50; the trivalent lanthanum group rare earth element A is dysprosium (Dy); The total content of the trivalent lanthanum group rare earth element A and terbium (Tb) is 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) in the main component of the base material, The auxiliary component does not contain Mg. Dielectric ceramic composition.

2. The dielectric ceramic composition according to claim 1, further comprising 0.0 to 4.0 moles of a first subcomponent which is an oxide or carbonate containing at least one of Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, and Sm relative to 100 moles of the base material main component.

3. The dielectric ceramic composition according to claim 1 or 2, further comprising 0.1 to 2.0 moles of a second subcomponent which is an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn, relative to 100 moles of the base material main component.

4. The dielectric ceramic composition according to any one of claims 1 to 3, further comprising 0.0 to 4.15 mol of a fourth subcomponent which is an oxide or carbonate containing Ba with respect to 100 mol of the base material main component.

5. The dielectric ceramic composition according to any one of claims 1 to 4, wherein the dielectric ceramic composition contains 0.0 to 20.0 moles of a fifth subcomponent which is an oxide or carbonate containing at least one of Ca and Zr with respect to 100 moles of the base material main component.

6. The dielectric ceramic composition according to any one of claims 1 to 5, further comprising 0.0 to 4.0 moles of a sixth subcomponent which is an oxide containing at least one of Si and Al or a glass compound containing Si, relative to 100 moles of the base material main component.

7. a ceramic body including a dielectric layer, and a first internal electrode and a second internal electrode disposed opposite each other with the dielectric layer interposed therebetween; a first external electrode disposed outside the ceramic body and electrically connected to the first internal electrode, and a second external electrode electrically connected to the second internal electrode, the dielectric layer comprises a dielectric ceramic composition; The dielectric ceramic composition is BaTiO ３ Contains the main and secondary components of the base material. The auxiliary component contains a trivalent lanthanum group rare earth element A and terbium (Tb) as rare earth elements, a ratio (Tb / A) of the content of the terbium (Tb) to the content of the trivalent lanthanum group rare earth element A satisfies 0.15≦Tb / A<0.50; the trivalent lanthanum group rare earth element A is dysprosium (Dy); The total content of the trivalent lanthanum group rare earth element A and terbium (Tb) is 0.2 mol or more and 1.5 mol or less per 100 mol of titanium (Ti) in the main component of the base material, The auxiliary component does not contain Mg. Multilayer ceramic capacitor.

8. The dielectric ceramic composition further contains 0.0 to 4.0 moles of a first subcomponent which is an oxide or carbonate containing at least one of Y, Ho, Er, Ce, Nd, Pm, Eu, Gd, Tm, Yb, Lu, and Sm relative to 100 moles of the base material main component. The multilayer ceramic capacitor according to claim 7.

9. The multilayer ceramic capacitor according to claim 7 or 8, wherein the dielectric ceramic composition further contains 0.1 to 2.0 mol of a second subcomponent which is an oxide or carbonate containing at least one of Mn, V, Cr, Fe, Ni, Co, Cu, and Zn, relative to 100 mol of the base material main component.

10. The multilayer ceramic capacitor according to any one of claims 7 to 9, wherein the dielectric ceramic composition further contains 0.0 to 4.15 mol of a fourth subcomponent which is an oxide or carbonate containing Ba with respect to 100 mol of the base material main component.

11. The multilayer ceramic capacitor according to any one of claims 7 to 10, wherein the dielectric ceramic composition further contains 0.0 to 20.0 mol of a fifth subcomponent which is an oxide or carbonate containing at least one of Ca and Zr.

12. The dielectric ceramic composition further contains 0.0 to 4.0 mol of a sixth subcomponent which is an oxide containing at least one of Si and Al or a glass compound containing Si, relative to 100 mol of the base material main component. The multilayer ceramic capacitor according to any one of claims 7 to 11.

13. 13. The multilayer ceramic capacitor according to claim 7, wherein the dielectric layers have a thickness of 0.45 μm or less, and the first internal electrodes and the second internal electrodes have a thickness of 0.45 μm or less.

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