Dielectric material, method of making the same, and multilayer ceramic capacitor including the same

Abstract

A dielectric material, a multilayer ceramic capacitor using the dielectric material, and a method for preparing the dielectric material are provided. The dielectric material comprises: a core comprising barium (Ba) and titanium (Ti); a first layer disposed on at least a portion of the core; and a second layer disposed on at least a portion of the first layer, wherein at least one of the first layer and the second layer comprises at least one first element selected from silicon (Si) and aluminum (Al), and the first layer and the second layer comprise at least one second element selected from tin (Sn), copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn).

Description

Technical Field

[0001] This disclosure relates to a dielectric material, a method for preparing the same, and a multilayer ceramic capacitor including the same. Background Technology

[0002] Ceramic electronic components that utilize ceramic materials include capacitors, inductors, piezoelectric elements, varistors, and thermistors. Among ceramic electronic components, multilayer ceramic capacitors (MLCCs) are used in various electronic devices due to their advantages such as small size, high capacitance, and ease of installation.

[0003] For example, a multilayer ceramic capacitor can be a chip capacitor mounted on a printed circuit board of various electronic products (such as imaging devices (e.g., liquid crystal displays (LCDs), plasma display panels (PDPs)), computers, personal portable terminals (e.g., smartphones)) for charging or discharging from them.

[0004] Recently, with the miniaturization of multilayer ceramic capacitors, the importance of micronization of dielectric matrix material powder and the distribution of additives is increasing. Summary of the Invention

[0005] The embodiment provides a dielectric material with a dielectric matrix material that minimizes core damage.

[0006] Another embodiment provides a method for preparing dielectric materials.

[0007] Another embodiment provides a multilayer ceramic capacitor with excellent temperature characteristics and reliability.

[0008] An embodiment provides a dielectric material comprising: a core comprising barium (Ba) and titanium (Ti); a first layer disposed on at least a portion of the core; and a second layer disposed on at least a portion of the first layer, wherein at least one of the first layer and the second layer comprises at least one first element selected from the group consisting of silicon (Si) and aluminum (Al), and the first layer and the second layer comprise at least one second element selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn).

[0009] The first and second layers may include tin (Sn), and when a TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis is performed on a straight portion from the center of the dielectric material to a boundary of the dielectric material, the first layer may be a region based on 100 moles of titanium (Ti) and tin (Sn) greater than or equal to about 0.2 moles, and the core and the second layer may be a region based on 100 moles of titanium (Ti) and tin (Sn) less than about 0.2 moles.

[0010] The content of the second element in the first layer may be higher than the content of the second element in the second layer.

[0011] The first layer and the second layer may include the first element.

[0012] The first layer and the second layer may include the second element in oxide form.

[0013] At least one of the first layer and the second layer may include silicon (Si), and the first layer and the second layer may include tin (Sn).

[0014] The first layer and the second layer may include silicon (Si) and tin (Sn).

[0015] Another embodiment provides a multilayer ceramic capacitor prepared by using the dielectric material, the multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and an inner electrode layer; and an outer electrode disposed on the outer surface of the capacitor body, wherein the dielectric layer prepared by using the dielectric material includes a plurality of dielectric grains and grain boundaries disposed between the plurality of dielectric grains, and at least one of the plurality of dielectric grains has a core-shell structure, the core-shell structure including a core and a shell disposed on at least a portion of the core, and the shell and the grain boundaries include at least one first element selected from the group consisting of silicon (Si) and aluminum (Al) and at least one second element selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn).

[0016] The molar ratio of the total amount of the second element in the shell to the total amount of the first element can be greater than about 0.15 and less than about 1.0.

[0017] The molar ratio of the second element included in the shell to the second element included in the grain boundary may be greater than or equal to about 2.0 and less than about 6.0.

[0018] The core may include barium (Ba) and titanium (Ti).

[0019] The shell and the grain boundary may include silicon (Si) and tin (Sn).

[0020] Another embodiment provides a method for preparing the dielectric material, the method comprising: adding a metal alkoxide compound to a solution comprising a barium titanate-based compound and performing hydrothermal treatment to initially coat the surface of the barium titanate-based compound with the metal alkoxide compound; and after the initial coating, adding a metal oxide and performing hydrothermal treatment to secondarily coat the surface of the metal alkoxide compound with the metal oxide, wherein the metal alkoxide compound comprises at least one element selected from the group consisting of silicon (Si) and aluminum (Al), and the metal oxide comprises at least one metal selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn).

[0021] The metal alkoxide compound may include at least one selected from the group consisting of tetraethyl orthosilicate (TEOS), aluminum isopropoxide, and aluminum ethoxide.

[0022] The metal alkoxide compound may be added in an amount such that the amount of at least one element in the metal alkoxide compound is about 0.1 moles to about 1 mole of 100 moles of the barium titanate compound.

[0023] The metal oxide may include at least one selected from the group consisting of tin oxide (SnO2), copper oxide (CuO), ferrous oxide (FeO), iron(II) oxide (Fe3O4), ferric oxide (Fe2O3), zinc oxide (ZnO), and manganese dioxide (MnO2).

[0024] The metal oxide can be added in an amount from about 0.1 moles to about 3 moles of the barium titanate-based compound based on 100 moles of the metal oxide.

[0025] In the initial coating, the hydrothermal treatment can be performed at a temperature of about 100°C to about 300°C.

[0026] In the secondary coating, the hydrothermal treatment can be performed at a temperature of about 150°C to about 350°C.

[0027] The dielectric materials according to some embodiments of this disclosure can minimize nucleus damage to the dielectric matrix material caused by doping additives. Multilayer ceramic capacitors using such dielectric materials can improve temperature characteristics and reliability. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating dielectric powder (i.e., dielectric material) according to an embodiment.

[0029] Figure 2 This is a perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0030] Figure 3 It is along Figure 2 A cross-sectional view of a multilayer ceramic capacitor taken by line I-I'.

[0031] Figure 4 It is along Figure 2 A cross-sectional view of a multilayer ceramic capacitor taken from line II-II'.

[0032] Figure 5 By splitting Figure 2 The capacitor body is shown in an exploded perspective view of the stacked structure.

[0033] Figure 6 This is a schematic diagram showing the dielectric layer according to an embodiment.

[0034] Figure 7A The images are based on HR-TEM (high resolution transmission electron microscopy) analysis of the dielectric powder prepared in Example 1.

[0035] Figure 7B The images are based on the IFFT HR-TEM (Inverse Fourier Transform High Resolution Transmission Electron Microscopy) analysis of the dielectric powder prepared in Example 1.

[0036] Figures 8A to 8C The images are based on TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis of the dielectric powder prepared in Example 1.

[0037] Figure 9A and Figure 9B The images are based on TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis images of the dielectric powder prepared in Example 1.

[0038] Figure 9C The graph is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis curve of the dielectric powder prepared in Example 1.

[0039] Figures 10A to 10D The image is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) mapping analysis of the dielectric layer in Example 1.

[0040] Figure 11A The image is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis image of the dielectric layer in Example 1.

[0041] Figure 11B It is a TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis curve of the dielectric layer in Example 1.

[0042] Figure 12This is a graph showing the reliability of the multilayer ceramic capacitor according to Example 1.

[0043] Figure 13 This is a graph showing the reliability of the multilayer ceramic capacitor according to Comparative Example 1. Detailed Implementation

[0044] The present disclosure will now be described in detail with reference to the accompanying drawings, in which embodiments of the disclosure are illustrated. The drawings and description are to be considered illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals denote the same elements. In the drawings, some components are exaggerated, omitted, or shown schematically, and the dimensions of each component do not perfectly reflect their actual dimensions.

[0045] The accompanying drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and it should be understood that the technical concepts disclosed herein are not limited to the drawings, and all variations, equivalents or alternatives within the scope of the technical concepts disclosed herein are included within the scope of this disclosure.

[0046] Although terms such as "first," "second," etc., are used to describe various components, the components are not limited by these terms. These terms are only used to distinguish one component from another.

[0047] Furthermore, it should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it may be directly on the other element, or there may be an intermediate element present. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element present. Additionally, when an element is referred to as being "on" or "above" a reference element, it may be located "above" or "below" the reference element, and it is not necessarily located "above" or "above" in a direction opposite to the direction of gravity.

[0048] Throughout this specification, the terms “comprising” or “having” are intended to specify the presence of the said features, quantities, steps, operations, components, parts, or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, steps, operations, components, parts, and / or combinations thereof. Therefore, unless explicitly stated otherwise, the words “comprising” and variations such as “including” or “having” will be understood to imply the inclusion of the said elements but not the exclusion of any other elements.

[0049] Furthermore, throughout the specification, the phrase "in plan view" or "on a plane" indicates the target portion as viewed from the top, and the phrase "in section view" or "on a section" indicates the section formed by vertically cutting the target portion as viewed from the side.

[0050] Throughout the specification, the term "connection" may mean not only that two or more constituent components are directly connected, but also that two or more constituent components are indirectly connected through another constituent component, that two or more constituent components are electrically connected and physically connected, or that two or more constituent components are referred to by different names according to their location and / or function, but are integrated with each other.

[0051] Furthermore, throughout the specification, when it is mentioned that "includes...as a main component", it means that among at least one component present in the region, one component has the highest content based on the total amount of at least one component.

[0052] Reference Figure 1 Describes the dielectric powder (i.e., dielectric material) according to the embodiments.

[0053] Figure 1 This is a schematic diagram illustrating dielectric powder according to an embodiment.

[0054] Reference Figure 1 According to some embodiments, the dielectric powder 10 may include a core 11, a first layer 12 disposed on at least a portion of the core 11, and a second layer 13 disposed on at least a portion of the first layer 12. In some embodiments, the first layer 12 may be disposed on the entire surface of the core 11, and / or the second layer 13 may be disposed on the entire surface of the first layer 12.

[0055] exist Figure 1 In the diagram, the first layer 12 is depicted as a structure surrounding the entire core 11, and the second layer 13 is depicted as a structure surrounding the entire first layer 12, but this is merely an example of the structure of the dielectric powder, and this disclosure is not limited thereto.

[0056] Core 11 may include barium (Ba) and titanium (Ti). At least one of the first layer 12 and the second layer 13 may include one or more first elements selected from the group consisting of silicon (Si) and aluminum (Al), and the first layer 12 and the second layer 13 may include one or more second elements selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn).

[0057] The composition of core 11 may be derived from a barium titanate-based compound used as the dielectric matrix material, and the compositions of the first layer 12 and the second layer 13 may be derived from additives. The additives may include a first element and a second element. That is, since the additives are doped into the bilayer structure of the first layer 12 and the second layer 13 on at least a portion of core 11, damage to the core due to additive doping can be minimized. Therefore, the dielectric powder having the above structure and composition can improve the temperature characteristics of the dielectric.

[0058] At least one of the first layer 12 and the second layer 13 may include a first element. According to some embodiments, the first element may include, for example, silicon (Si). According to some embodiments, the first element may include, for example, aluminum (Al). Additionally, according to some embodiments, both the first layer 12 and the second layer 13 may include a first element. According to some embodiments, the first layer may include at least one first element selected from the group consisting of silicon (Si) and aluminum (Al). According to some embodiments, the second layer may include at least one first element selected from the group consisting of silicon (Si) and aluminum (Al).

[0059] According to some embodiments, the first layer 12 and the second layer 13 may include a second element. According to some embodiments, the second element may be derived from an internal diffusion additive and may include, for example, tin (Sn). According to some embodiments, the second element may be selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn).

[0060] The content of the second element included in the first layer 12 may be higher than the content of the second element included in the second layer 13. When the content of the second element (such as Sn) in the first layer 12 is higher than the content of the second element (such as Sn) in the second layer 13, the diffusion of additive components into the dielectric grains can be suppressed, thereby improving the temperature characteristics of the dielectric.

[0061] The second element can exist in the form of oxides in the first layer 12 and the second layer 13.

[0062] For example, at least one of the first layer 12 and the second layer 13 may include silicon (Si), and the first layer 12 and the second layer 13 may include tin (Sn).

[0063] Additionally, as an example, both the first layer 12 and the second layer 13 may include silicon (Si) and tin (Sn).

[0064] The structure of dielectric powder 10 can be confirmed by HR-TEM (high resolution transmission electron microscopy) or IFFT HR-TEM (inverse Fourier transform high resolution transmission electron microscopy).

[0065] Specifically, the dielectric powder 10 can be measured using HR-TEM or IFFT-HR-TEM at an accelerating voltage of 200 kV and a magnification of 630 k. The core 11, the first layer 12, and the second layer 13 can be distinguished and identified through the measurement images.

[0066] In addition, the structure and composition of the dielectric powder 10 can also be confirmed by TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis.

[0067] Specifically, the structure and composition of the dielectric powder 10 can be confirmed by measuring the dielectric powder 10 using a transmission electron microscope (TEM) at an accelerating voltage of 200 kV and a magnification of 630 kV to obtain a TEM image, and then performing energy-dispersive spectroscopy (EDS) analysis on the obtained TEM image. Alternatively, the composition of the dielectric powder can be confirmed by performing EDS line analysis on a straight line portion from the center of the dielectric powder to one of its boundaries in the measured TEM image.

[0068] For example, when the first layer 12 and the second layer 13 include Sn, when performing TEM-EDS analysis on the straight portion from the center of the dielectric powder to one side boundary, the core 11, the first layer 12, and the second layer 13 can be distinguished based on the point where Sn is about 0.2 moles (relative to 100 moles of Ti). That is, the first layer 12 can be defined as a region where Sn is greater than or equal to about 0.2 moles (relative to 100 moles of Ti), and the core 11 and the second layer 13 can be defined as regions where Sn is less than 0.2 moles (relative to 100 moles of Ti). The inner region of the first layer 12 towards the center of the dielectric powder can be defined as the core 11, and the outer region of the first layer 12 towards the outside can be defined as the second layer 13.

[0069] The aforementioned dielectric powder can be prepared by the following methods: A metal alkoxide compound is added to a solution containing a barium titanate-based compound and subjected to hydrothermal treatment to initially coat the surface of the barium titanate-based compound with the metal alkoxide compound; and after the initial coating, a metal oxide is added and subjected to hydrothermal treatment to secondarily coat the surface of the metal alkoxide compound with the metal oxide.

[0070] Barium titanate-based compounds are compounds comprising barium (Ba) and titanium (Ti), and may include at least one selected from the group consisting of BaTiO3, Ba(Ti, Zr)O3, Ba(Ti, Sn)O3, (Ba, Ca)TiO3, (Ba, Ca)(Ti, Ca)O3, (Ba, Ca)(Ti, Zr)O3, (Ba, Ca)(Ti, Sn)O3, (Ba, Sr)TiO3, (Ba, Sr)(Ti, Zr)O3 and (Ba, Sr)(Ti, Sn)O3.

[0071] Metal alkoxide compounds can be alkoxide compounds comprising one or more elements selected from silicon (Si) and aluminum (Al). In this disclosure, metal alkoxide compounds may also include half-metal alkoxide compounds (or metal-like alkoxide compounds). That is, metal alkoxide compounds may include metals such as aluminum (Al) or half-metals (or metal-like compounds) such as silicon (Si). In the dielectric powder 10 according to some embodiments, the first element may be derived from a metal alkoxide compound initially coated on the surface of a barium titanate-based compound.

[0072] The metal oxide can be an oxide of one or more metals selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn). In another embodiment, the second element in the dielectric powder 10 may be derived from the metal oxide that is secondary coated on the surface of the metal alkoxide compound initially coated.

[0073] According to the method for preparing dielectric powder disclosed herein, a first barrier layer is formed by initially coating a metal alkoxide compound onto the surface of a barium titanate-based compound. This first barrier layer blocks the movement of internal diffusion additives corresponding to the metal oxide to be coated a second time. Furthermore, by second-coating a metal oxide onto the surface of the initially coated metal alkoxide compound, a second barrier layer corresponding to the internal diffusion additive layer is formed on top of the first barrier layer, thereby minimizing damage to the core. In other words, by forming a double barrier layer, core damage caused by additive doping is minimized, and the temperature characteristics of the dielectric can be easily ensured.

[0074] Specifically, the initial coating can be achieved by forming a first layer as a barrier layer on the surface of the barium titanate-based compound by adding a metal alkoxide compound to a solution containing the barium titanate-based compound whose grain growth has been completed, followed by dissolution and re-precipitation of the compound. In other words, the first layer can be formed by precipitating a reaction product of the metal alkoxide compound with Ba and Ti on the surface of the barium titanate-based compound through polymerization and neutralization reactions after the hydrolysis of the added metal alkoxide compound.

[0075] Solutions containing barium titanate compounds can be aqueous or organic solutions; for example, solutions containing barium titanate compounds can be aqueous solutions. For aqueous solutions, this can be, for example, a solution with a pH higher than 7.

[0076] Metal alkoxide compounds may include one or more selected from, for example, tetraethyl orthosilicate (TEOS), aluminum isopropoxide, and aluminum ethoxide.

[0077] The metal alkoxide compound can be added in an amount such that the amount of metal is from about 0.1 moles to about 1 mole (based on 100 moles of barium titanate-based compound), and the metal alkoxide compound can be added in an amount such that the amount of metal, such as Si, is, for example, from about 0.1 moles to about 0.8 moles or from about 0.2 moles to about 0.6 moles (based on 100 moles of barium titanate-based compound). When the metal alkoxide compound is added within the above-mentioned content range, a first layer as a barrier layer that prevents the movement of internally diffused additives can be easily formed.

[0078] In the initial coating, hydrothermal treatment can be performed at a temperature of about 100°C to about 300°C, for example, at a temperature of about 150°C to about 250°C. When the initial coating is performed hydrothermally within the above temperature range, the metal alkoxide compound is stably hydrolyzed, making it easy to perform the initial coating on the surface of the barium titanate-based compound.

[0079] Furthermore, during the initial coating, the temperature can be maintained and the mixture stirred for a period of time (e.g., more than about 30 minutes) to ensure complete hydrolysis of the metal alkoxide compound. Additionally, the reaction time and temperature can be controlled according to the amount of metal alkoxide compound added and the type of material, and the reaction temperature can be lower than the grain growth temperature of the barium titanate-based compound.

[0080] Furthermore, secondary coating can be used to form a second layer as a barrier layer on the surface of barium titanate-based compound powder by adding a metal oxide to a solution containing barium titanate-based compound powder on which a first layer as a barrier layer has been formed by the initial coating, and then dissolving and re-precipitating the compound.

[0081] The metal oxide may include one or more selected from, for example, the group consisting of tin oxide (SnO2), copper oxide (CuO), ferrous oxide (FeO), iron(II,III) oxide (Fe3O4), ferric oxide (Fe2O3), zinc oxide (ZnO), and manganese dioxide (MnO2). The metal oxide may be used, for example, in the form of a sol solution in which the metal oxide is dispersed in an alkaline solvent.

[0082] The metal oxide can be added in an amount such that the amount of metal is from about 0.1 moles to about 3 moles (based on 100 moles of barium titanate-based compound), and the metal oxide can be added in an amount such that the amount of metal, such as Sn, is from about 0.2 moles to about 2.5 moles or from about 0.5 moles to about 2.0 moles (based on 100 moles of barium titanate-based compound). When the metal oxide is added within the above-mentioned content range, a second layer of internal diffusion additive layer can be easily formed on the first layer, thereby minimizing damage to the core.

[0083] In the secondary coating, hydrothermal treatment can be performed at a temperature of about 150°C to about 350°C, for example, at a temperature of about 200°C to about 300°C. When the heat treatment for secondary coating is performed within the above temperature range, the metal oxides are stably dissolved and re-precipitated, thus the secondary coating can be easily performed on the surface of the barium titanate-based compound.

[0084] Furthermore, during the secondary coating process, the temperature can be maintained for a period of time (e.g., more than about 2 hours) to ensure sufficient dissolution of the metal oxide. Additionally, the reaction time and temperature can be controlled according to the amount of metal oxide and the type of material, and the reaction temperature can be lower than the grain growth temperature of the barium titanate-based compound.

[0085] In the following text, refer to Figures 2 to 5 A multilayer ceramic capacitor using the aforementioned dielectric powder is described.

[0086] Figure 2 This is a perspective view showing a multilayer ceramic capacitor according to an embodiment. Figure 3 It is along Figure 2 A cross-sectional view of a multilayer ceramic capacitor taken by line I-I'. Figure 4 It is along Figure 2 A cross-sectional view of a multilayer ceramic capacitor taken from line II-II', and Figure 5 By splitting Figure 2 The capacitor body is shown in an exploded perspective view of the stacked structure.

[0087] Figures 2 to 5 The L-axis, W-axis, and T-axis shown represent the length, width, and thickness directions of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) can be perpendicular to the wide surface (main surface) of the sheet assembly and can be used as the same concept as, for example, the stacking direction of the stacked dielectric layers 111. The length direction (L-axis direction) can be a direction extending parallel to the wide surface (main surface) of the sheet assembly and can be substantially perpendicular to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) can be the direction in which the first external electrode 131 and the second external electrode 132 are opposite each other. The width direction (W-axis direction) can be a direction extending parallel to the wide surface (main surface) of the sheet assembly and can be substantially perpendicular to both the thickness direction (T-axis direction) and the length direction (L-axis direction). The length of the sheet assembly in the length direction (L-axis direction) can be longer than its length in the width direction (W-axis direction).

[0088] Reference Figures 2 to 5According to some embodiments, a multilayer ceramic capacitor 100 includes a capacitor body 110 and external electrodes 131 and 132 disposed on the outer surface of the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 disposed at opposite ends of the capacitor body 110 in the longitudinal direction (L-axis direction).

[0089] For example, the capacitor body 110 may have a generally hexahedral shape.

[0090] For ease of description of the embodiments, the two surfaces of the capacitor body 110 that are opposite to each other in the thickness direction (T-axis direction) are referred to as the first surface and the second surface, the two surfaces of the capacitor body 110 that are connected to the first surface and the second surface and are opposite to each other in the length direction (L-axis direction) are referred to as the third surface and the fourth surface, and the two surfaces of the capacitor body 110 that are connected to the first surface and the second surface, connected to the third surface and the fourth surface, and are opposite to each other in the width direction (W-axis direction) are referred to as the fifth surface and the sixth surface.

[0091] As an example, the first surface, which serves as the lower surface, can be a mounting surface. Alternatively, the first to sixth surfaces can be flat, but the embodiment is not limited to this. For example, the first to sixth surfaces can be curved surfaces with a convex central portion, and the edges of each surface (the boundaries between the surfaces) can be rounded.

[0092] The shape and size of the capacitor body 110 and the number of stacked dielectric layers 111 are not limited to the shape and size of the capacitor body and the number of stacked dielectric layers shown in the accompanying drawings of the embodiment.

[0093] The capacitor body 110 may include a plurality of dielectric layers 111 and a plurality of internal electrode layers 121 and 122. Specifically, the capacitor body 110 may include a plurality of dielectric layers 111, a plurality of first internal electrode layers 121 and a plurality of second internal electrode layers 122, wherein the first internal electrode layers 121 and the second internal electrode layers 122 are alternately arranged in the thickness direction (T-axis direction) and the dielectric layer 111 is located between the first internal electrode layers 121 and the second internal electrode layers 122.

[0094] Here, the dielectric layer 111 of the capacitor body 110 can be integrated to such an extent that the boundary between adjacent dielectric layers 111 is difficult to distinguish without the use of a scanning electron microscope (SEM).

[0095] The capacitor body 110 may include an effective area and coverage areas 112 and 113.

[0096] The effective region is the area where dielectric layer 111 and inner electrode layers 121 and 122 are stacked alternately, which contributes to the capacitance of the multilayer ceramic capacitor 100. Specifically, the effective region can be the area where the first inner electrode layer 121 and the second inner electrode layer 122 are stacked along the thickness direction (T-axis direction).

[0097] Cover regions 112 and 113 are thickness-direction edges and can be respectively disposed on the upper and lower surfaces of the effective region in the thickness direction (T-axis direction). Cover regions 112 and 113 can be a single dielectric layer or two or more dielectric layers stacked on the upper and lower surfaces of the effective region, respectively.

[0098] In addition, the capacitor body 110 may also include a side edge region.

[0099] The side edge region is an edge portion in the width direction and can be disposed on the opposite side surfaces of the effective region in the width direction (W-axis direction) (i.e., the side surfaces corresponding to the fifth and sixth surfaces). The side edge region can be formed by stacking dielectric green sheets and then firing the dielectric green sheets, wherein the dielectric green sheets are coated with conductive paste only in a portion of the surface of the dielectric green sheets and are not coated with conductive paste in the two side regions of the surface of the dielectric green sheets, but the formation method is not limited to this.

[0100] Covered areas 112 and 113, as well as side edge areas, can be used to prevent damage to the inner electrode layers 121 and 122 due to physical stress and / or chemical stress.

[0101] dielectric layer Reference Figure 6 Describes the dielectric layer according to an embodiment.

[0102] Figure 6 This is a schematic diagram showing the dielectric layer according to an embodiment.

[0103] Reference Figure 6 The dielectric layer 111 may include a plurality of dielectric grains 20 and grain boundaries 30 disposed between the plurality of dielectric grains 20.

[0104] At least one of the plurality of dielectric grains 20 may have a core-shell structure, the core-shell structure including a core portion 21 and a shell portion 22 disposed on at least a portion of the core portion 21. According to some embodiments, the shell portion 22 may be disposed on the entire surface of the core portion 21.

[0105] The dielectric layer 111 may be formed from a dielectric paste comprising the aforementioned dielectric powder.

[0106] Specifically, the core 21 may include barium (Ba) and titanium (Ti), and the shell 22 and grain boundary 30 may include at least one first element selected from the group consisting of silicon (Si) and aluminum (Al); and at least one second element selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn). When both the shell 22 and the grain boundary 30 include the first and second elements, damage to the core caused by additive doping into the dielectric matrix material can be minimized, thus ensuring a multilayer ceramic capacitor with improved temperature characteristics and reliability. That is, the dielectric layer 111 according to some embodiments of this disclosure can have a structure and composition that controls the diffusion of additive components by using the aforementioned dielectric powder through a first layer as a barrier layer (the first layer is formed by coating a metal alkoxide compound) and a second layer as a barrier layer (the second layer is formed by coating a metal oxide), thereby improving the temperature characteristics and reliability of the multilayer ceramic capacitor.

[0107] The composition of the core 21 may be derived from a barium titanate-based compound used as a dielectric matrix material in the manufacture of the aforementioned dielectric powder. Barium titanate-based compounds have a high dielectric constant and contribute to the capacitance of the multilayer ceramic capacitor 100.

[0108] For example, barium titanate-based compounds may include at least one selected from the group consisting of BaTiO3, Ba(Ti, Zr)O3, Ba(Ti, Sn)O3, (Ba,Ca)TiO3, (Ba, Ca)(Ti, Ca)O3, (Ba, Ca)(Ti, Zr)O3, (Ba, Ca)(Ti, Sn)O3, (Ba, Sr)TiO3, (Ba, Sr)(Ti, Zr)O3 and (Ba, Sr)(Ti, Sn)O3.

[0109] The first element may be derived from a metal alkoxide compound that is initially coated on the surface of a barium titanate-based compound during the preparation of the aforementioned dielectric powder, and the second element may be derived from a metal oxide that is secondarily coated on the surface of the initially coated metal alkoxide compound during the preparation of the aforementioned dielectric powder.

[0110] For example, the shell 22 and the grain boundary 30 may include silicon (Si) and tin (Sn).

[0111] The structure and composition of dielectric layer 111 can be confirmed by TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy). TEM-EDS analysis can be performed using the following methods.

[0112] After the multilayer ceramic capacitor 100 is placed in an epoxy resin mixture and cured, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body 110 are polished to half the depth of the capacitor body 110 in the L-axis direction to obtain a cross-sectional sample, allowing observation of the effective region where the dielectric layer 111 is stacked with the inner electrode layers 121 and 122. Subsequently, the effective region of the cross-sectional sample is divided into three parts (i.e., an upper region, a central region, and a lower region), and each region is measured using transmission electron microscopy (TEM) so that at least one dielectric layer and at least one inner electrode layer in each region are visible. TEM measurements can be performed using Xe-FIB (focused ion beam) at an accelerating voltage of 200 kV and a magnification of 450 k. EDS (energy-dispersive spectroscopy) analysis is then performed on the dielectric layer in the obtained TEM image of the cross-sectional sample to confirm the structure and composition of the dielectric grains 20 and grain boundaries 30 with a core-shell structure.

[0113] At this point, as a method to more clearly identify the core 21, shell 22, and grain boundary 30, the Dy element as a secondary component can be utilized. For example, when performing TEM-EDS line analysis along the long axis passing through the center of a dielectric grain with a core-shell structure, regions where Dy is greater than about 0.3 moles of Ti per 100 moles can be defined as grain boundaries, regions where Dy is between about 0.15 moles and about 0.3 moles of Ti per 100 moles can be defined as shells, and regions where Dy is less than about 0.15 moles of Ti per 100 moles can be defined as cores.

[0114] According to some embodiments, the molar ratio of the second element to the first element in the shell 22 may be greater than about 0.15 and less than about 1.0, for example, it may be about 0.2 to about 0.9, about 0.3 to about 0.8, or about 0.4 to about 0.6. When the molar ratio of the second element to the first element in the shell 22 is within the above range, the temperature characteristics and reliability of the multilayer ceramic capacitor can be improved by minimizing the damage to the core caused by the doping of additives into the dielectric matrix material.

[0115] Furthermore, the molar ratio of the second element included in the shell 22 to the second element included in the grain boundary 30 can be greater than or equal to about 2.0 and less than about 6.0, for example, greater than or equal to about 3.0 and less than about 6.0, or greater than or equal to about 4.0 and less than about 6.0. When the molar ratio of the second element in the shell 22 to the second element in the grain boundary 30 is within the above range, the temperature characteristics and reliability of the multilayer ceramic capacitor can be improved by minimizing the damage to the core caused by the doping of additives into the dielectric matrix material.

[0116] In other words, the dielectric layer 111 according to the embodiment uses the aforementioned dielectric powder, such that due to the diffusion control effect of the additive components obtained by the first layer (formed by coating a metal alkoxide compound) and the second layer (formed by coating a metal oxide) as barrier layers, the additive components are present in the shell and grain boundaries in a predetermined proportion range. Therefore, a multilayer ceramic capacitor with excellent temperature characteristics and reliability can be obtained.

[0117] The molar ratio of the second element to the first element in the shell 22 and the molar ratio of the second element in the shell 22 to the second element in the grain boundary 30 can be measured as follows.

[0118] After the multilayer ceramic capacitor 100 is placed in an epoxy resin mixture and cured, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body 110 are polished to half the depth of the capacitor body 110 in the L-axis direction to obtain a cross-sectional sample, allowing observation of the effective region where the dielectric layer 111 and the inner electrode layers 121 and 122 are stacked. Subsequently, the effective region of the cross-sectional sample is divided into three parts (i.e., an upper region, a central region, and a lower region), and each region is measured using transmission electron microscopy (TEM) so that at least one dielectric layer and at least one inner electrode layer in each region are visible. TEM measurements can be performed using Xe-FIB (focused ion beam) at an accelerating voltage of 200 kV and a magnification of 450 k.

[0119] Next, in the TEM images of the upper, central, and lower regions, at least one dielectric grain with a core-shell structure is selected for each region. EDS line analysis can then be performed on the straight section from the center of the dielectric grain to a grain boundary. For example, by selecting three dielectric grains from the upper region, four from the central region, and three from the lower region, EDS line analysis can be performed on each of a total of 10 dielectric grains.

[0120] Subsequently, the molar ratio of the second element (E2) to the first element (E1) in the shell 22 can be obtained by measuring the E2 / E1 molar ratio within the shell of each dielectric grain and averaging the values ​​for a total of 10 dielectric grains. In this case, the E2 / E1 molar ratio within the shell of each dielectric grain can be obtained by measuring the E2 / E1 molar ratio at three equally spaced points within the shell of a dielectric grain and then averaging these values. Furthermore, the E2 / E1 molar ratio at each point can be the molar ratio of E1 and E2 content measured based on 100 moles of Ti at that point.

[0121] Furthermore, the molar ratio of the second element in the shell 22 to the second element in the grain boundary 30 can be obtained by measuring the molar ratio of the second element in the shell to the second element in the grain boundary of each dielectric grain and taking the average value for a total of 10 dielectric grains. In this case, the molar ratio of the second element in the shell to the second element in the grain boundary of each dielectric grain can be obtained by measuring the content of the second element at three equally spaced points in the shell and three equally spaced points in the grain boundary of a dielectric grain, and then taking the average value of the molar ratio of the second element in the shell to the second element in the grain boundary for three arbitrary cases (three arbitrary combinations). Additionally, the content of the second element at each point can be measured based on 100 moles of Ti at that point.

[0122] In addition to the aforementioned components, dielectric layer 111 may also include one or more sub-components selected from manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), and vanadium (V), and for example, dielectric layer 111 may also include dysprosium (Dy).

[0123] The average thickness (average length in the T-axis direction) of the dielectric layer 111 can be from about 0.1 μm to about 8.0 μm, for example, from about 0.1 μm to about 6.0 μm. If the dielectric layer 111 has an average thickness within the range described above, the multilayer ceramic capacitor can exhibit excellent reliability.

[0124] The average thickness of dielectric layer 111 can be measured by placing the multilayer ceramic capacitor 100 in an epoxy resin mixture, curing it, polishing it, then ion-milling it, and then analyzing it using a scanning electron microscope (SEM). The SEM can be performed at, for example, an accelerating voltage of 10 kV and a magnification of 100x, and can be measured such that at least one, three, five, or ten layers of dielectric layer 111 are visible in the effective region where dielectric layer 111 is stacked with inner electrode layers 121 and 122. In the SEM image, the center point of dielectric layer 111 in the length direction (L-axis direction) or width direction (W-axis direction) is used as a reference point, and the average thickness of dielectric layer 111 at 10 points spaced at predetermined intervals from the reference point can be obtained. The interval of the 10 points can be adjusted according to the scale of the SEM image and can be, for example, about 1 μm to about 100 μm, about 1 μm to about 50 μm, or about 1 μm to about 10 μm. Here, all 10 points should be located within dielectric layer 111. If not all 10 points are located within dielectric layer 111, the position of the reference point can be changed, or the spacing between the 10 points can be adjusted. The spacing here refers to the distance between two adjacent points. Furthermore, by extending this average measurement to 10 dielectric layers, the average thickness of the dielectric layers can be more generalized.

[0125] Inner electrode layer The inner electrode layers 121 and 122 (i.e., the first inner electrode layer 121 and the second inner electrode layer 122) are electrodes with different polarities and are alternately arranged to face each other along the T-axis direction. The dielectric layer 111 is located between the inner electrode layers 121 and 122, and one end of the first inner electrode layer 121 and one end of the second inner electrode layer 122 can be exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0126] The first inner electrode layer 121 and the second inner electrode layer 122 are electrically insulated from each other by a dielectric layer 111 disposed therebetween.

[0127] The ends of the first inner electrode layer 121 and the second inner electrode layer 122, which are alternately exposed through the third and fourth surfaces of the capacitor body 110, can be electrically connected to the first outer electrode 131 and the second outer electrode 132, respectively.

[0128] The inner electrode layers 121 and 122 comprise conductive metals and may include at least one metal selected from Ni, Cu, Ag, Pd, Au, and alloys thereof.

[0129] Additionally, inner electrode layers 121 and 122 may include dielectric particles having the same composition as the ceramic material included in dielectric layer 111.

[0130] The inner electrode layers 121 and 122 can be formed using a conductive paste comprising a conductive metal. The printing method for the conductive paste can be screen printing or gravure printing.

[0131] The average thickness of the inner electrode layers 121 and 122 can be from about 0.1 μm to about 2 μm.

[0132] The average thickness of the inner electrode layers 121 and 122 can be measured by scanning electron microscopy (SEM) analysis. Specifically, in an SEM image of a cross-sectional sample obtained using the same method as used to measure the average thickness of the dielectric layer 111, the central point of the inner electrode layers 121 and 122 in the length direction (L-axis direction) or width direction (W-axis direction) is used as a reference point, and the average thickness of the inner electrode layers 121 and 122 at 10 points spaced at predetermined intervals from the reference point can be obtained. The interval of the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image and can be, for example, about 1 μm to about 100 μm, about 1 μm to about 50 μm, or about 1 μm to about 10 μm. In this case, all 10 points should be located within the inner electrode layers 121 and 122, and if not all 10 points are located within the inner electrode layers 121 and 122, the position of the reference point can be changed, or the interval between the 10 points can be adjusted. Here, the interval can refer to the interval between two adjacent points. Furthermore, by extending this average measurement to 10 inner electrode layers, the average thickness of the inner electrode layers can be more generalized.

[0133] The capacitor body 110 can be formed by firing a stacked structure in which multiple dielectric layers 111 and multiple internal electrode layers 121 and 122 are stacked.

[0134] external electrode The first external electrode 131 and the second external electrode 132 are provided with voltages of different polarities and can be electrically connected to the exposed portions of the first inner electrode layer 121 and the second inner electrode layer 122, respectively.

[0135] According to the above structure, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charge accumulates between the first inner electrode layer 121 and the second inner electrode layer 122 facing each other. At this time, the capacitance of the multilayer ceramic capacitor 100 is proportional to the stacked area of ​​the first inner electrode layer 121 and the second inner electrode layer 122 stacked together along the T-axis in the effective region.

[0136] The first external electrode 131 may include a first connecting portion and a first strip portion. The first connecting portion is disposed on the third surface of the capacitor body 110 and connected to the first inner electrode layer 121. The first strip portion is disposed on the edge where the third surface of the capacitor body 110 intersects with the first surface and the second surface and / or the fifth surface and the sixth surface. The second external electrode 132 may include a second connecting portion and a second strip portion. The second connecting portion is disposed on the fourth surface of the capacitor body 110 and connected to the second inner electrode layer 122. The second strip portion is disposed on the edge where the fourth surface of the capacitor body 110 intersects with the first surface and the second surface and / or the fifth surface and the sixth surface.

[0137] The first strip may extend from the first connecting portion to a portion of the first surface, a portion of the second surface, and / or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110. The second strip may extend from the second connecting portion to a portion of the first surface, a portion of the second surface, and / or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110. The first strip and the second strip can be used to improve the bonding strength between the first external electrode 131 and the second external electrode 132 and the capacitor body 110.

[0138] The external electrodes 131 and 132 may include a sintered metal layer in contact with the capacitor body 110, a conductive resin layer configured to cover the sintered metal layer, and a plating layer configured to cover the conductive resin layer.

[0139] The sintered metal layer may include conductive metals and glass.

[0140] The conductive metal may include at least one of copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), and alloys thereof, and for example, when the conductive metal includes copper (Cu), it may mean that the conductive metal may include copper (Cu) metal or copper (Cu) alloys. When the conductive metal includes copper (Cu), based on 100 molar parts of copper (Cu), metals other than copper (Cu) may be included in an amount of less than or equal to about 5 molar parts.

[0141] The glass may comprise a composition of oxides (e.g., one or more selected from silicon oxides, boron oxides, aluminum oxides, transition metal oxides, alkali metal oxides, and alkaline earth metal oxides). The transition metal may be at least one selected from zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni); the alkali metal may be at least one selected from lithium (Li), sodium (Na), and potassium (K); and the alkaline earth metal may be at least one selected from magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0142] Optionally, the conductive resin layer may be formed on the sintered metal layer, and for example, may be formed in a shape that completely covers the sintered metal layer. Additionally, the first external electrode 131 and the second external electrode 132 may not include the sintered metal layer, and in this case, the conductive resin layer may directly contact the capacitor body 110.

[0143] The conductive resin layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the strip portion) where the conductive resin layer extends and is disposed on the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the strip portion) where the sintered metal layer extends and is disposed on the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. In other words, the conductive resin layer may be formed on the sintered metal layer and may be formed in a shape that completely covers the sintered metal layer.

[0144] The conductive resin layer may include resin and conductive metal.

[0145] The resin included in the conductive resin layer can be, but is not limited to, a material that has adhesive and damping properties and can form a paste when mixed with conductive metal powder. For example, the resin may include phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0146] The conductive metal included in the conductive resin layer is used to electrically connect the inner electrode layers 121 and 122 or the sintered metal layer to the plating layer.

[0147] The conductive metal included in the conductive resin layer may have a spherical shape, a sheet shape, or a combination thereof. That is, the conductive metal may be formed only in a sheet shape, only in a spherical shape, or in a mixed form of sheet and spherical shapes.

[0148] Here, spherical shape can also include shapes that are not perfect spheres, such as shapes whose length ratio of major axis to minor axis (major axis / minor axis) is less than or equal to about 1.45. Sheet shape refers to a flat and elongated shape, and there are no particular restrictions, such as shapes whose length ratio of major axis to minor axis (major axis / minor axis) is greater than or equal to about 1.95.

[0149] The external electrodes 131 and 132 may also include a plating layer disposed on the outer surface of the conductive resin layer.

[0150] The coating may include individual nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb), or alloys thereof. For example, the coating may be a nickel (Ni) coating or a tin (Sn) coating, which may be in the form of nickel (Ni) coatings and tin (Sn) coatings stacked sequentially, or in the form of tin (Sn) coatings, nickel (Ni) coatings, and tin (Sn) coatings stacked sequentially. Alternatively, the coating may include multiple nickel (Ni) coatings and / or multiple tin (Sn) coatings.

[0151] The coating can improve the mountability, structural reliability, external durability, heat resistance and equivalent series resistance (ESR) of the multilayer ceramic capacitor 100 on the substrate.

[0152] Hereinafter, a method for manufacturing a multilayer ceramic capacitor 100 according to an embodiment will be described.

[0153] The multilayer ceramic capacitor 100 according to the embodiment can be manufactured by: preparing a dielectric paste including the aforementioned dielectric powder; using the dielectric paste to manufacture a dielectric green sheet and forming a conductive paste layer on the surface of the dielectric green sheet; manufacturing a dielectric green sheet stack by stacking the dielectric green sheets on which the conductive paste layer is formed; firing the dielectric green sheet stack to manufacture a capacitor body including a dielectric layer and an inner electrode layer; and forming an outer electrode on the outer surface of the capacitor body.

[0154] As described above, dielectric powder can be prepared by first coating a metal alkoxide compound onto the surface of a barium titanate-based compound, and then secondly coating a metal oxide onto the surface of the first-coated metal alkoxide compound.

[0155] Dielectric pastes may also include by-component powders, i.e., compounds containing by-components.

[0156] Compounds containing byproducts may include compounds comprising one or more byproducts selected from the group consisting of manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), and vanadium (V), and for example, may include compounds containing dysprosium (Dy).

[0157] The compound containing byproducts can be at least one of the oxides, nitrides, and salts of the byproducts, and can also be a compound in sol form dispersed in an organic solvent.

[0158] It may include compounds containing byproducts, such that, based on 100 molar parts of barium titanate-based compound, the amount of byproducts is from about 0.9 molar parts to about 1.5 molar parts.

[0159] Dielectric pastes can be prepared by further mixing with additives such as dispersants, binders, plasticizers, lubricants, antistatic agents, and solvents.

[0160] The dispersant may include, for example, phosphate ester dispersants, polycarboxylic acid dispersants, or combinations thereof. Based on 100 parts by weight of a barium titanate-based compound, the dispersant can be mixed in amounts from about 0.1 parts by weight to about 5 parts by weight (e.g., from about 0.3 parts by weight to about 3 parts by weight). When the dispersant is mixed within the above-mentioned content range, the dielectric paste exhibits excellent dispersibility and reduces the amount of impurities included in the manufactured dielectric layer.

[0161] The adhesive may include, for example, acrylic resins, polyvinyl butyral resins, polyvinyl acetal resins, ethyl cellulose, etc. Based on 100 parts by weight of a barium titanate-based compound, the adhesive may be added in amounts from about 0.1 parts by weight to about 50 parts by weight (e.g., from about 3 parts by weight to about 30 parts by weight). When the adhesive is mixed within the above-mentioned content range, the dielectric paste exhibits excellent dispersibility and reduces the amount of impurities included in the manufactured dielectric layer.

[0162] Plasticizers may include, for example: phthalic acid compounds such as dioctyl phthalate, butyl benzyl phthalate, dibutyl phthalate, dihexyl phthalate, di(2-ethylhexyl) phthalate, and di(2-ethylbutyl) phthalate; adipate compounds such as dihexyl adipate and di(2-ethylhexyl) adipate; glycol compounds such as ethylene glycol, diethylene glycol, and triethylene glycol; glycol ester compounds such as triethylene glycol dibutyrate, triethylene glycol di(2-ethylbutyrate), and triethylene glycol di(2-ethylhexanoate); and the like. Based on 100 parts by weight of a barium titanate-based compound, the plasticizer may be added in an amount of about 0.1 parts by weight to about 20 parts by weight (e.g., about 1 part by weight to about 10 parts by weight). When plasticizers are mixed within the above-mentioned content range, the dielectric paste exhibits excellent dispersibility and reduces the amount of impurities included in the manufactured dielectric layer.

[0163] Solvents may include: aqueous solvents, such as water; alcohol solvents, such as ethanol, methanol, benzyl alcohol, and methoxyethanol; glycol solvents, such as ethylene glycol and diethylene glycol; ketone solvents, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents, such as butyl acetate, ethyl acetate, carbitol acetate, and butyl carbitol acetate; ether solvents, such as methyl cellosolve, ethyl cellosolve, butyl ether, and tetrahydrofuran; and aromatic solvents, such as benzene, toluene, and xylene. Considering the solubility or dispersibility of various additives included in the dielectric paste, solvents may include, for example, alcohol solvents or aromatic solvents. Based on 100 parts by weight of the barium titanate compound, solvents can be mixed in amounts from about 50 parts by weight to about 1000 parts by weight (e.g., from about 100 parts by weight to about 500 parts by weight). When solvents are mixed within the above-mentioned content range, the dielectric paste components can be sufficiently mixed, and subsequent solvent removal is easy.

[0164] The dielectric slurry described above can be mixed using a wet ball mill or a stirred mill. When using zirconia balls in a wet ball mill, multiple zirconia balls with a diameter of about 0.1 mm to about 10 mm can be used for wet mixing for about 8 hours to about 48 hours or about 10 hours to about 24 hours.

[0165] The prepared dielectric paste forms a dielectric layer after firing.

[0166] As a method for forming the prepared dielectric paste into a sheet, a strip forming method such as a doctor blade method or a calendering roll method can be used. For example, a coating head discharge type roller forming coating machine can be used, and the dielectric sheet can then be obtained by drying the formed body.

[0167] To form a conductive paste layer that becomes the inner electrode layer after firing, the conductive paste can be prepared by mixing conductive powder made of conductive metals or alloys thereof, a binder, and a solvent. Additionally, barium titanate powder can be mixed in as a co-material if desired. The co-material can be used to suppress the sintering of the conductive powder during the sintering process. In the manufacture of dielectric green sheets, a dielectric paste can be prepared by mixing a barium titanate-based compound as the main component powder and optional secondary component powders.

[0168] The conductive powder may include nickel (Ni) or nickel (Ni) alloys.

[0169] Next, a dielectric green sheet stack is manufactured by stacking multiple dielectric green sheets on which an inner electrode layer pattern (i.e., a conductive paste layer) is formed, and then pressing the multiple dielectric green sheets in the stacking direction. At this time, dielectric green sheets on which no inner electrode layer pattern is formed can be stacked, such that dielectric green sheets on which no inner electrode layer pattern is formed are disposed at the upper and lower parts of the dielectric green sheet stack in the stacking direction.

[0170] Optionally, the step of cutting the manufactured dielectric sheet stack into a predetermined size by cutting or the like can be performed.

[0171] Additionally, if necessary, the dielectric green sheet stack can be cured and dried to remove plasticizers, etc., and after curing and drying, the dielectric green sheet stack can be tumble polished using a horizontal centrifugal tumbler or similar device. In tumble polishing, the dielectric green sheet stack is placed in a tumbler container containing a dielectric and polishing fluid, and rotational motion or vibration is applied to the tumbler container, thus polishing away unwanted parts (such as burrs generated during cutting). After tumble polishing, the dielectric green sheet stack can be washed with a cleaning solution such as water and dried.

[0172] Subsequently, the capacitor body can be obtained after adhesive removal (calcination) and firing treatment of the dielectric green sheet stack.

[0173] The conditions for adhesive removal can be appropriately adjusted according to the composition of the dielectric layer and / or the inner electrode layer. For example, the heating rate during adhesive removal can be from about 5°C / hour to about 300°C / hour, the holding temperature can be from about 180°C to about 400°C, and the temperature holding time can be from about 0.5 hours to about 24 hours. Adhesive removal can be performed in an air atmosphere or a reducing atmosphere.

[0174] The firing conditions can be appropriately adjusted according to the main component composition of the dielectric layer and / or the main component composition of the inner electrode layer. For example, firing can be carried out at a temperature of about 1100°C to about 1400°C, or for example, at a temperature of about 1200°C to about 1350°C. Furthermore, firing can be carried out for about 0.5 hours to about 8 hours, or for example, about 1 hour to about 3 hours. Additionally, firing can be carried out in a reducing atmosphere, for example, in an atmosphere wetted by a mixture of nitrogen and hydrogen, and under conditions such as a hydrogen concentration of less than or equal to about 1.0%. When the inner electrode layer comprises nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere can be about 1.0 × 10⁻⁶. -14 MPa to approximately 1.0 × 10 -10 MPa.

[0175] After firing, annealing can be performed as needed. Annealing is a process that re-oxidizes the dielectric layer; it can be performed if firing is carried out in a reducing atmosphere. The annealing conditions can also be adjusted appropriately according to the composition of the dielectric layer. For example, the annealing temperature can be from about 950°C to about 1150°C, the time can be greater than about 0 hours and less than or equal to about 20 hours, and the heating rate can be from about 50°C / hour to about 500°C / hour. The annealing atmosphere can be a moistened nitrogen (N2) atmosphere, and the oxygen partial pressure can be about 1.0 × 10⁻⁶. -9 MPa to approximately 1.0 × 10 -5MPa.

[0176] In the adhesive removal process, firing process, or annealing process, for example, a wetting agent may be used to wet the nitrogen or mixed gas. In this case, the wetting agent temperature (e.g., water temperature) may be from about 5°C to about 75°C. The adhesive removal process, firing process, and annealing process may be performed sequentially or independently.

[0177] Optionally, the third and fourth surfaces of the prepared capacitor body 110 may be subjected to surface treatments such as sandblasting, laser irradiation, or tumble polishing. By performing this surface treatment, the ends of the first inner electrode layer and the second inner electrode layer can be exposed to the third and fourth surfaces, respectively, thereby improving the electrical connection between the first inner electrode layer and the first outer electrode, as well as between the second inner electrode layer and the second outer electrode, and facilitating the formation of alloy portions.

[0178] Subsequently, an external electrode is formed on the outer surface of the manufactured capacitor body 110.

[0179] As an example, a paste for forming a sintered metal layer can be applied to the outer surface of the capacitor body 110 and then sintered to form a sintered metal layer.

[0180] The paste used to form the sintered metal layer may include conductive metals and glass. Since the descriptions of conductive metals and glass are the same as described above, repeated descriptions will be omitted. Additionally, the paste used to form the sintered metal layer may optionally include binders, solvents, dispersants, plasticizers, oxide powders, etc. The binder may be, for example, ethyl cellulose, acrylic resin, butyral resin, etc., and the solvent may be, for example, an organic solvent or an aqueous solvent such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.

[0181] Methods for applying paste for forming a sintered metal layer to the outer surface of the capacitor body 110 may include dipping, various printing methods (such as screen printing), coating using a dispenser, and spraying using a sprayer. The paste for forming the sintered metal layer may be applied to at least the third and fourth surfaces of the capacitor body 110, and optionally to portions of the first, second, fifth, and / or sixth surfaces on which the first and second external electrodes are formed.

[0182] Subsequently, the capacitor body 110 coated with paste for forming a sintered metal layer is dried and fired at a temperature of about 700°C to about 1000°C for about 0.1 hours to about 3 hours to form a sintered metal layer.

[0183] Optionally, a paste for forming a conductive resin layer is applied to the outer surface of the obtained capacitor body 110 and then cured to form a conductive resin layer.

[0184] The paste used to form the conductive resin layer may include conductive metals and resins, and optionally include non-conductive fillers. Since the descriptions of the conductive metals and resins are the same as described above, repeated descriptions will be omitted. Additionally, the paste used to form the conductive resin layer may optionally include binders, solvents, dispersants, plasticizers, oxide powders, etc. The binders may be, for example, ethyl cellulose, acrylic resins, butyral resins, etc., and the solvents may be organic solvents or aqueous solvents such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, and toluene.

[0185] For example, the conductive resin layer can be formed by immersing the capacitor body 110 in a paste for forming the conductive resin layer and then curing it, or by printing the paste for forming the conductive resin layer onto the surface of the capacitor body 110 by screen printing or gravure printing and then curing it, or by applying the paste for forming the conductive resin layer onto the surface of the capacitor body 110 and then curing it.

[0186] Next, a plating layer is formed on the outer surface of the conductive resin layer.

[0187] For example, the coating can be formed by plating (e.g., electroplating (electrodeposition)) or sputtering.

[0188] Embodiments of this disclosure are described in more detail below with reference to examples. However, these examples are exemplary, and the scope of the claims is not limited thereto.

[0189] (Preparation of dielectric powder) Preparation Example 1 Tetraethyl orthosilicate (TEOS) was added to a slurry containing BaTiO3 dispersed in an aqueous solution, followed by hydrothermal treatment at 200°C to perform a primary coating of TEOS on the surface of BaTiO3. At this point, TEOS was added in an amount such that Si was 0.24 moles (based on 100 moles of BaTiO3). Subsequently, SnO2 was added to the slurry containing the intermediate from the primary coating, followed by hydrothermal treatment at 250°C to perform a secondary coating of SnO2 on the surface of the primary coated TEOS, thereby preparing a dielectric powder. Here, SnO2 was introduced in the form of a sol dispersed in ammonia water, and in an amount such that Sn was 1 mole (based on 100 moles of BaTiO3).

[0190] Preparation Example 2 Except for adding TEOS in an amount that makes Si 0.41 moles (based on 100 moles of BaTiO3), the dielectric powder was prepared using the same method as in Preparation Example 1.

[0191] Preparation Example 3 Except that SnO2 was added in an amount that makes Sn 1.5 moles (based on 100 moles of BaTiO3), dielectric powder was prepared using the same method as in Preparation Example 1.

[0192] Preparation Example 4 Except that SnO2 was added in an amount that makes Sn 2 moles (based on 100 moles of BaTiO3), dielectric powder was prepared using the same method as in Preparation Example 1.

[0193] Comparative Preparation Example 1 The dielectric powder is prepared by adding SnO2 to a slurry comprising BaTiO3 dispersed in an aqueous solution, and then heat-treating the slurry at 250°C to coat the surface of BaTiO3 with SnO2. In this process, SnO2 is introduced in the form of a sol dispersed in ammonia water, and in an amount such that Sn is 1 molar part (based on 100 molar parts of BaTiO3).

[0194] (Manufacturing of multilayer ceramic capacitors) Example 1 Dielectric paste was prepared by mixing the dielectric powder prepared in Preparation Example 1 with a by-component powder including Dy2O3. Dy2O3 was mixed in an amount of 1.3 moles of Dy, based on 100 moles of BaTiO3 used in the preparation of the dielectric powder. In preparing the dielectric paste, after adding ethanol / toluene, a wetting and dispersing agent, and polyvinyl butyral (PVB) resin as a binder, the mixture was mechanically ground using zirconia (ZrO2) balls as a dispersion medium.

[0195] Dielectric green sheets are manufactured using the prepared dielectric paste by using a coating head discharge roller forming coating machine.

[0196] A conductive paste layer including nickel (Ni) is printed on the surface of a dielectric green sheet, and then dielectric green sheets with the conductive paste layer formed on them are stacked and then pressed to manufacture a dielectric green sheet stack.

[0197] The dielectric green sheet stack is calcined at 400°C or lower under a nitrogen atmosphere and then calcined at 1300°C or lower under a hydrogen (H2) concentration of 1.0% or lower to obtain the capacitor body.

[0198] Subsequently, an external electrode is formed on the obtained capacitor body through processes such as plating to obtain a multilayer ceramic capacitor.

[0199] Example 2 The multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that the dielectric powder prepared in Preparation Example 2 was used instead of the dielectric powder prepared in Preparation Example 1.

[0200] Example 3 The multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that the dielectric powder prepared in Preparation Example 3 was used instead of the dielectric powder prepared in Preparation Example 1.

[0201] Example 4 The multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that the dielectric powder prepared in Preparation Example 4 was used instead of the dielectric powder prepared in Preparation Example 1.

[0202] Comparative Example 1 In addition to preparing dielectric paste by mixing BaTiO3 with by-product powders including SiO2 and Dy2O3, multilayer ceramic capacitors are manufactured in the same manner as in Example 1.

[0203] Evaluation 1: Confirmation of the structure and composition of the dielectric powder To confirm the structure of the dielectric powder prepared in Preparation Example 1, HR-TEM (high-resolution transmission electron microscopy) and IFFT HR-TEM (inverse Fourier transform high-resolution transmission electron microscopy) analyses were performed, and the results are shown in... Figure 7A and Figure 7B middle.

[0204] HR-TEM and IFFT HR-TEM analyses were performed on dielectric powders under accelerating voltage of 200 kV and a magnification of 630 k.

[0205] Figure 7A The images were obtained from HR-TEM (high resolution transmission electron microscopy) analysis of the dielectric powder prepared in Example 1, and Figure 7B The images are based on the IFFT HR-TEM (Inverse Fourier Transform High Resolution Transmission Electron Microscopy) analysis of the dielectric powder prepared in Example 1.

[0206] Reference Figure 7A and Figure 7B It was confirmed that the dielectric powder of Preparation Example 1 has a structure including a core, a first layer disposed on at least a portion of the core, and a second layer disposed on at least a portion of the first layer. Furthermore, the BaTiO3 core is present inside the dielectric powder of Preparation Example 1 without damage, and on the outside, a layer with a modified crystal structure is distributed due to the metal oxide coating.

[0207] Furthermore, the dielectric powder prepared in Example 1 was analyzed by TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) to examine its structure and composition, and the results are shown in... Figures 8A to 8C and Figures 9A to 9C middle.

[0208] TEM-EDS analysis was performed as follows. Images of the dielectric powder were captured using a TEM (transmission electron microscope) at an accelerating voltage of 200 kV and a magnification of 630 kΩ. EDS (energy-dispersive spectroscopy) analysis was then performed on the TEM images to examine the structure and composition of the dielectric powder. Furthermore, EDS line analysis was performed on the straight sections from the center of the dielectric powder to its boundary on either side of the acquired TEM images to examine the composition of the dielectric powder.

[0209] Figures 8A to 8C The images are based on TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) analysis of the dielectric powder prepared in Example 1. Figure 9A and Figure 9B The images were obtained from TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis of the dielectric powder prepared in Example 1, and Figure 9C The graph is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis curve of the dielectric powder prepared in Example 1.

[0210] Reference Figures 8A to 8C It was confirmed that the dielectric powder of Preparation Example 1 has a structure including a core, a first layer disposed on at least a portion of the core, and a second layer disposed on at least a portion of the first layer, wherein both Si and Sn are present in the first and second layers. Furthermore, in the dielectric powder, due to the first layer acting as a barrier layer, the metal oxide does not diffuse further into the interior, but instead forms the second layer as a barrier layer.

[0211] Additionally, refer to Figures 9A to 9C The TEM-EDS line analysis results distinguished the core, the first layer, and the second layer based on points where Sn was 0.2 moles (based on 100 moles of Ti). In other words, the first layer is the region where Sn is greater than or equal to approximately 0.2 moles (based on 100 moles of Ti), while the core and the second layer are the regions where Sn is less than 0.2 moles (based on 100 moles of Ti). The core is defined as the inner region relative to the first layer and facing the center of the dielectric powder, while the second layer is the outer region relative to the first layer and facing the outside of the dielectric powder.

[0212] Evaluation 2: TEM-EDS analysis of the dielectric layer The dielectric layers of the multilayer ceramic capacitors according to Examples 1 to 4 and Comparative Example 1 were analyzed by TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) according to the following method, and the results are shown in... Figures 10A to 10D as well as Figure 11A and Figure 11B middle.

[0213] Each multilayer ceramic capacitor was placed in an epoxy resin mixture and cured. The W-axis and T-axis surfaces (WT surfaces) of the capacitor body were then polished to half the depth of the capacitor body in the L-axis direction to obtain a cross-sectional sample for examining the effective region of the dielectric layer and inner electrode layer stack. Subsequently, the effective region of the cross-sectional sample was divided into three areas (e.g., upper, central, and lower regions), and images of each region were captured using TEM (transmission electron microscopy) to allow observation of at least one dielectric layer and at least one inner electrode layer in each region. TEM images were obtained using Xe-FIB (focused ion beam) at an accelerating voltage of 200 kV and a magnification of 450 k. EDS (energy-dispersive spectroscopy) analysis of the dielectric layer was then performed on the TEM images of the cross-sectional sample.

[0214] Furthermore, in the TEM images of the cross-sectional samples, TEM-EDS line analysis was performed along the long axis passing through the center of the dielectric grains with the core-shell structure.

[0215] Figures 10A to 10D The image is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) mapping analysis of the dielectric layer in Example 1. Figure 11A The image is based on the TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis of the dielectric layer in Example 1, and Figure 11B It is a TEM-EDS (transmission electron microscopy-energy dispersive spectroscopy) line analysis curve of the dielectric layer in Example 1.

[0216] Reference Figures 10A to 10D It is confirmed that the dielectric layer of Example 1 includes dielectric grains and grain boundaries with a core-shell structure, wherein Si and Sn are present in both the shell and the grain boundaries.

[0217] In addition, refer to Figure 11A and Figure 11B According to the TEM-EDS line analysis results, in the TEM-EDS line analysis along the long axis passing through the center of the dielectric grain with core-shell structure, the region where Dy is greater than about 0.3 moles (relative to 100 moles of Ti) can be defined as a grain boundary, the region where Dy is between about 0.15 moles and about 0.3 moles (relative to 100 moles of Ti) can be defined as a shell, and the region where Dy is less than about 0.15 moles (relative to 100 moles of Ti) can be defined as a core.

[0218] In addition, the Sn / Si molar ratio (X) in the shell and the molar ratio (Y) of Sn in the shell to Sn in the grain boundary were measured according to the following method, and the results are shown in Table 1.

[0219] In the TEM images of the upper, central, and lower regions of the effective region, three dielectric grains were selected from the upper region, four from the central region, and three from the lower region, for a total of ten dielectric grains with a core-shell structure. EDS line analysis was performed on the straight line portion from the center of each selected dielectric grain to the grain boundary on either side.

[0220] Subsequently, in Table 1, X was obtained by measuring the Sn / Si molar ratio within the shell of each dielectric grain and calculating the average of ten measurements. Here, the Sn / Si molar ratio of the shell of each dielectric grain was obtained by measuring the Sn / Si molar ratio at three equally spaced points within a dielectric grain and calculating the average of the measured values. Furthermore, the Sn / Si molar ratio at each point was based on the molar ratio of Sn content and Si content per 100 moles of Ti.

[0221] Furthermore, in Table 1, Y is obtained by measuring the molar ratio of Sn in the shell to Sn at the grain boundaries of each dielectric grain and calculating the average of ten measurements. Here, the molar ratio of Sn in the shell to Sn at the grain boundaries of each dielectric grain is obtained by measuring the Sn content at three equally spaced points in the shell of a dielectric grain and the Sn content at three equally spaced points in the grain boundaries, and calculating the average of the molar ratio of Sn content in the shell to Sn content in the grain boundaries for three arbitrary cases (three arbitrary combinations).

[0222] In addition, the Sn content at each point was measured based on 100 moles of Ti at each point.

[0223] (Table 1)

[0224] Evaluation 3: Dielectric constant The dielectric constants of the multilayer ceramic capacitors according to Examples 1 to 4 and Comparative Example 1 were measured at 1 kHz and 0.5 V, and the results are shown in Table 2.

[0225] Evaluation 4: Temperature Characteristics The temperature coefficient of capacitance (TCC) of the multilayer ceramic capacitors of Examples 1 to 4 and Comparative Example 1 was measured, and the results are shown in Table 2.

[0226] TCC was measured at 1 kHz, 0.01 V, and a holding time of 5 minutes.

[0227] Evaluation 5: Reliability The mean time to failure (MTTF) of the multilayer ceramic capacitors in Examples 1 to 4 and Comparative Example 1 were measured using the following method, and the results are shown in Table 2. Figure 12 and Figure 13 middle.

[0228] The MTTF (Mean Time To Failure) (in hours) was obtained by calculating the average value of 20 multilayer ceramic capacitor samples for each of Examples 1 to 4 and Comparative Example 1 under conditions of 125°C, 9.45V, and 48 hours.

[0229] Figure 12 This is a graph showing the reliability of the multilayer ceramic capacitor according to Example 1, and Figure 13 This is a graph showing the reliability of the multilayer ceramic capacitor according to Comparative Example 1.

[0230] Reference Figure 12 and Figure 13 Compared to Comparative Example 1, Example 1 demonstrates superior reliability.

[0231] (Table 2)

[0232] Referring to Table 2, compared to Comparative Example 1, Examples 1 to 4 exhibit high dielectric constants, excellent temperature characteristics achieved due to small capacitance changes at high temperatures, and excellent reliability. Therefore, multilayer ceramic capacitors using dielectric powders according to embodiments of the present disclosure exhibit excellent temperature characteristics and reliability, in which the dielectric layer comprises dielectric grains and grain boundaries having a core-shell structure, and the shell and grain boundaries comprise Si and Sn.

[0233] Although this disclosure has been described in conjunction with embodiments now considered to be practical, it should be understood that this disclosure is not limited to the disclosed embodiments, but rather is intended to cover various variations and equivalents included within the spirit and scope of the appended claims.

[0234] <Explanation of reference numerals in the attached drawings> 10: Dielectric powder 11: Nuclear 12: First floor 13: Second layer 20: Dielectric grains 21: Nuclear Department 22: Shell 30: Grain boundary 100: Multilayer ceramic capacitor 110: Capacitor body 111: Dielectric layer 121: First inner electrode layer 122: Second inner electrode layer 131: First external electrode 132: Second external electrode.

Claims

1. A dielectric material, comprising: The core consists of barium (Ba) and titanium (Ti); The first layer is disposed on at least a portion of the core; as well as The second layer is disposed on at least a portion of the first layer. Wherein, at least one of the first layer and the second layer includes at least one first element selected from the group consisting of silicon (Si) and aluminum (Al), and The first layer and the second layer include at least one second element selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn).

2. The dielectric material according to claim 1, wherein, The first and second layers comprise tin (Sn), and When performing transmission electron microscopy-energy dispersive spectroscopy analysis on a straight section from the center of the dielectric material to one of its boundaries, The first layer is based on a region of 100 moles of titanium (Ti) and 0.2 moles of tin (Sn), and The core and the second layer are regions based on 100 moles of titanium (Ti) and less than 0.2 moles of tin (Sn).

3. The dielectric material according to claim 1, wherein, The content of the second element in the first layer is higher than that in the second layer.

4. The dielectric material according to claim 1, wherein, The first layer and the second layer include the first element.

5. The dielectric material according to claim 1, wherein, The first layer and the second layer comprise the second element in oxide form.

6. The dielectric material according to claim 1, wherein, At least one of the first layer and the second layer comprises silicon (Si). The first and second layers comprise tin (Sn).

7. The dielectric material according to claim 1, wherein, The first layer and the second layer comprise silicon (Si) and tin (Sn).

8. A multilayer ceramic capacitor, comprising: The capacitor body includes a dielectric layer and an inner electrode layer; as well as External electrodes are disposed on the outer surface of the capacitor body. The dielectric layer includes a plurality of dielectric grains and grain boundaries disposed between the plurality of dielectric grains. At least one of the plurality of dielectric grains has a core-shell structure, the core-shell structure comprising a core and a shell disposed on at least a portion of the core, and The shell and the grain boundary comprise at least one first element selected from the group consisting of silicon (Si) and aluminum (Al) and at least one second element selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn).

9. The multilayer ceramic capacitor according to claim 8, wherein, The molar ratio of the second element to the first element in the shell is greater than 0.15 and less than 1.

0.

10. The multilayer ceramic capacitor according to claim 8, wherein, The molar ratio of the second element included in the shell to the second element included in the grain boundary is greater than or equal to 2.0 and less than 6.

0.

11. The multilayer ceramic capacitor according to claim 8, wherein, The core comprises barium (Ba) and titanium (Ti).

12. The multilayer ceramic capacitor according to claim 8, wherein, The shell and the grain boundary comprise silicon (Si) and tin (Sn).

13. A multilayer ceramic capacitor, comprising: The capacitor body includes a dielectric layer and an inner electrode layer; as well as External electrodes are disposed on the outer surface of the capacitor body. The dielectric layer is prepared from the dielectric material according to claim 1, and includes a plurality of dielectric grains and grain boundaries disposed between the plurality of dielectric grains. At least one of the plurality of dielectric grains has a core-shell structure, the core-shell structure comprising a core and a shell disposed on at least a portion of the core, and The shell and the grain boundary comprise at least one first element selected from the group consisting of silicon (Si) and aluminum (Al) and at least one second element selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn).

14. The multilayer ceramic capacitor according to claim 13, wherein, The molar ratio of the second element to the first element in the shell is greater than 0.15 and less than 1.

0.

15. The multilayer ceramic capacitor according to claim 13, wherein, The molar ratio of the second element included in the shell to the second element included in the grain boundary is greater than or equal to 2.0 and less than 6.

0.

16. The multilayer ceramic capacitor according to claim 13, wherein, The core comprises barium (Ba) and titanium (Ti).

17. The multilayer ceramic capacitor according to claim 13, wherein, The shell and the grain boundary comprise silicon (Si) and tin (Sn).

18. A method for preparing the dielectric material according to claim 1, comprising: Metal alkoxide compounds are added to solutions containing barium titanate compounds; Hydrothermal treatment is performed to initially coat the surface of the barium titanate-based compound with the metal alkoxide compound; as well as A metal oxide is added and subjected to hydrothermal treatment to a secondary coating of the metal oxide onto the surface of the metal alkoxide compound. The metal alkoxide compound comprises at least one element selected from the group consisting of silicon (Si) and aluminum (Al), and The metal oxide includes at least one metal selected from the group consisting of tin (Sn), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn).

19. The method according to claim 18, wherein, The metal alkoxide compound includes at least one selected from the group consisting of tetraethyl orthosilicate, aluminum isopropoxide, and aluminum ethoxide.

20. The method according to claim 18, wherein, The metal alkoxide compound is added such that the amount of at least one element in the metal alkoxide compound is from 0.1 to 1 mole of 100 moles of the barium titanate compound.

21. The method according to claim 18, wherein, The metal oxide includes at least one selected from tin oxide (SnO2), copper oxide (CuO), ferrous oxide (FeO), iron(II,III) oxide (Fe3O4), ferric oxide (Fe2O3), zinc oxide (ZnO), and manganese dioxide (MnO2).

22. The method according to claim 18, wherein, The metal oxide is added such that the amount of the at least one metal in the metal oxide is from 0.1 to 3 moles based on 100 moles of the barium titanate compound.

23. The method according to claim 18, wherein, In the initial coating, the hydrothermal treatment is performed at a temperature of 100°C to 300°C.

24. The method according to claim 18, wherein, In the secondary coating, the hydrothermal treatment is performed at a temperature of 150°C to 350°C.

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