Multilayer ceramic capacitor and method of manufacturing same

Abstract

The invention provides a multilayer ceramic capacitor and a method of manufacturing the same. The multilayer ceramic capacitor may include: a capacitor body including a dielectric layer and an inner electrode layer; and an external electrode disposed outside the capacitor body, in which the dielectric layer may include at least one dielectric crystal grain, in which the dielectric crystal grain may include a barium titanate-based main component including barium (Ba) and titanium (Ti), and a sub-component, in which the sub-component may include samarium (Sm) as a first sub-component, and a second sub-component, in which the second sub-component may include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), wherein, based on 100 atom% of titanium (Ti), the second sub-component included in the dielectric grains may be in the range of 1.2 atom% to 2.0 atom%, based on 100 atom% of titanium (Ti), and wherein the second sub-component included in the dielectric grains may be in the range of 1.2 atom% to 2.0 atom%, based on 100 atom% of titanium (Ti).

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic capacitor and a method for manufacturing the same. Background Art

[0002] As electronic components using ceramic materials, there are capacitors, inductors, piezoelectric elements, varistors, thermistors, etc. Among ceramic electronic components, multilayer ceramic capacitors (MLCCs) can be used in various electronic devices due to advantages such as small size, high capacitance, and easy installation.

[0003] For example, multilayer ceramic capacitors (MLCCs) can be used in chip capacitors mounted on boards of various electronic products (such as image devices (e.g., liquid crystal displays (LCDs), plasma display panels (PDPs), etc.), computers, personal portable terminals, smartphones, etc.) for charging or discharging them.

[0004] Recently, as MLCCs become more highly integrated, they have gradually become thinner, and high reliability needs to be ensured under a thin layer design. Summary of the Invention

[0005] The present disclosure attempts to provide an excellent multilayer ceramic capacitor having improved DC bias characteristics and reliability.

[0006] In addition, the present disclosure attempts to provide a method for manufacturing a multilayer ceramic capacitor.

[0007] A multilayer ceramic capacitor may include: a capacitor body including a dielectric layer and an internal electrode layer; and an external electrode provided outside the capacitor body, wherein the dielectric layer may include at least one dielectric grain, wherein the dielectric grain may include a barium titanate-based main component containing barium (Ba) and titanium (Ti) and a sub-component, wherein the sub-component may include samarium (Sm) as a first sub-component and a second sub-component, wherein the second sub-component may include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or a combination thereof, and wherein, based on 100 atomic% of titanium (Ti), the amount of the second sub-component included in the dielectric grain may be in the range of 1.2 atomic% to 2.0 atomic%.

[0008] The second sub-component may include terbium (Tb), dysprosium (Dy), or a combination thereof.

[0009] The dielectric grains may include a core and a shell surrounding at least a portion of the core, the second secondary component may be included in the core and the shell, and the atomic percentage of the second secondary component included in the shell may be higher than the atomic percentage of the second secondary component included in the core.

[0010] The atomic ratio of the second secondary component included in the shell to the second secondary component included in the core may be in the range of 2 to 8.

[0011] Based on 100 atomic % of titanium (Ti), the amount of samarium (Sm) included in the dielectric grains may be in the range of 0.01 atomic % to 1.2 atomic %.

[0012] The dielectric grains may include a core and a shell surrounding at least a portion of the core, samarium (Sm) may be included in the core and the shell, and the atomic % of samarium (Sm) included in the shell may be higher than the atomic % of samarium (Sm) included in the core.

[0013] The atomic ratio of samarium (Sm) included in the shell to samarium (Sm) included in the core may be in the range of 1.2 to 2.5.

[0014] The secondary component may further include a third secondary component, and the third secondary component includes aluminum (Al), silicon (Si), magnesium (Mg), manganese (Mn), or a combination thereof.

[0015] Based on 100 atomic % of titanium (Ti), the amount of the third secondary component included in the dielectric grains may be in the range of 0.1 atomic % to 2.5 atomic %.

[0016] The third secondary component may include aluminum (Al) and silicon (Si).

[0017] The atomic ratio of samarium (Sm) to the sum of aluminum (Al) and silicon (Si) may be in the range of 0.01 to 0.7.

[0018] The diameter of the dielectric grains may be in the range of 100 nm to 500 nm based on the longest axis.

[0019] A method for manufacturing a multilayer ceramic capacitor may include: preparing a dielectric paste by mixing barium titanate-based main component powder and sub-component powder, the sub-component powder including a samarium (Sm)-containing compound and a second sub-component-containing compound; manufacturing a dielectric green sheet using the dielectric paste and forming a conductive paste layer on the surface of the dielectric green sheet; manufacturing a dielectric green sheet laminate by stacking the dielectric green sheets having the conductive paste layer formed thereon; manufacturing a capacitor body including a dielectric layer and an internal electrode layer by firing the dielectric green sheet laminate; and forming an external electrode on the surface of the capacitor body, wherein the second sub-component-containing compound may include a lanthanum (La)-containing compound, a cerium (Ce)-containing compound, a praseodymium (Pr)-containing compound, a neodymium (Nd)-containing compound, a promethium (Pm)-containing compound, a europium (Eu)-containing compound, a gadolinium (Gd)-containing compound, a terbium (Tb)-containing compound, a dysprosium (Dy)-containing compound, a holmium (Ho)-containing compound, an erbium (Er)-containing compound, a thulium (Tm)-containing compound, a ytterbium (Yb)-containing compound, a lutetium (Lu)-containing compound, or a combination thereof, and wherein, based on 100 mole parts of the barium titanate-based main component powder, the amount of the second sub-component in the second sub-component-containing compound included in the dielectric paste may be in the range of 1.2 mole parts to 2.0 mole parts.

[0020] The second sub-component-containing compound may include a terbium (Tb)-containing compound, a dysprosium (Dy)-containing compound, or a combination thereof.

[0021] Based on 100 mole parts of the barium titanate-based main component powder, the amount of samarium (Sm) in the samarium (Sm)-containing compound included in the dielectric paste may be in the range of 0.01 mole parts to 1.2 mole parts.

[0022] The sub-component powder may further include a third sub-component-containing compound, the third sub-component-containing compound including an aluminum (Al)-containing compound, a silicon (Si)-containing compound, a magnesium (Mg)-containing compound, a manganese (Mn)-containing compound, or a combination thereof.

[0023] Based on 100 mole parts of the barium titanate-based main component powder, the amount of the third sub-component in the third sub-component-containing compound included in the dielectric paste may be in the range of 0.1 mole parts to 2.5 mole parts.

[0024] The third sub-component-containing compound may include the aluminum (Al)-containing compound and the silicon (Si)-containing compound.

[0025] A dielectric material having dielectric grains may include: a main component including a barium titanate-based compound; and sub-components including a first sub-component and a second sub-component, the first sub-component including samarium (Sm), and the second sub-component including a metal selected from the group consisting of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and combinations thereof, wherein, based on 100 atomic % of titanium (Ti), the amount of the second sub-component included in the dielectric material may be in the range of 1.2 atomic % to 2.0 atomic %.

[0026] The dielectric grains may include a core and a shell surrounding at least a part of the core, both the core and the shell including the second sub-component, and the atomic percentage of the second sub-component included in the shell may be higher than the atomic percentage of the second sub-component included in the core.

[0027] A multilayer ceramic capacitor according to an embodiment may improve DC bias characteristics and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0029] Figure 2 is along Figure 1 a cross-sectional view of the multilayer ceramic capacitor taken along line I-I'.

[0030] Figure 3 is along Figure 1 a cross-sectional view of the multilayer ceramic capacitor taken along line II-II'.

[0031] Figure 4 is a low magnification TEM image of a dielectric layer according to Example 1.

[0032] Figure 5 is regarding Figure 4 an EDS line analysis diagram of the dielectric grains shown in.

[0033] Figure 6 is a high magnification TEM image of a dielectric layer according to Example 1.

[0034] Figure 7 is a graph showing the high temperature severe reliability of a multilayer ceramic capacitor according to Comparative Example 1.

[0035] Figure 8 is a graph showing the high temperature severe reliability of a multilayer ceramic capacitor according to Example 3.

[0036] Figure 9It is a graph showing the high-temperature severe reliability of a multilayer ceramic capacitor according to Example 5. Detailed Description of the Invention

[0037] Hereinafter, the present disclosure will be described in detail with reference to the drawings showing embodiments of the present disclosure. The drawings and the description are considered to be 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 schematically shown, and the dimensions of each component do not exactly reflect the actual dimensions.

[0038] The drawings are only intended to facilitate the understanding of the embodiments disclosed in this specification, and it should be understood that the technical ideas disclosed herein are not limited by the drawings and include all variations, equivalents, or alternative solutions within the scope of the ideas and technologies of the present disclosure.

[0039] Although terms such as "first", "second", etc. are used to explain various components, the components are not limited to such terms. These terms are only used to distinguish one component from another.

[0040] In addition, it will 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 also be an intermediate element. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element. Further, 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 does not necessarily lie "on" or "above" in the direction opposite to the direction of gravity.

[0041] Throughout the specification, the term "comprising" or "having" is intended to specify the presence of the stated features, numbers, steps, operations, components, or combinations thereof, but does not exclude the presence or addition of one or more other features, numbers, steps, operations, components, and / or their groups. Therefore, unless explicitly described to the contrary, the words "comprising" and variations such as "including" or "containing" will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.

[0042] Furthermore, throughout the specification, the phrase "in a plan view" or "on a plane" means observing the target part from the top, and the phrase "in a sectional view" or "in a section" means observing the section formed by vertically cutting the target part from the side.

[0043] Throughout the specification, the term "connected" not only means that two or more constituent components are directly connected, but also means that two or more constituent components are indirectly connected through another constituent component, two or more components are electrically connected and physically connected, or two or more constituent components are referred to by different names but are coupled by position or function.

[0044] In the following, reference will be made to Figures 1 to 3 describe a multilayer ceramic capacitor according to an embodiment.

[0045] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment. Figure 2 is along Figure 1 A cross-sectional view of the multilayer ceramic capacitor taken along line I-I'. Figure 3 is along Figure 1 A cross-sectional view of the multilayer ceramic capacitor taken along line II-II'.

[0046] Figures 1 to 3 The L-axis direction, W-axis direction, and T-axis direction shown in are the length direction, width direction, and thickness direction of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) may be a direction perpendicular to the wide surface (main surface) of the sheet-like component, and may be used as the same concept as the stacking direction of, for example, the stacked dielectric layers 111. The length direction (L-axis direction) may be a direction extending parallel to the wide surface (main surface) of the sheet-like component, and may be substantially perpendicular to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be the direction in which the first outer electrode 131 and the second outer electrode 132 face each other. The width direction (W-axis direction) may be a direction extending parallel to the wide surface (main surface) of the sheet-like component, and may be substantially perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction). The length of the sheet-like component in the length direction (L-axis direction) may be longer than the width in the width direction (W-axis direction).

[0047] Refer to Figures 1 to 3 , the multilayer ceramic capacitor 100 according to an embodiment includes a capacitor body 110 and outer electrodes 131 and 132 provided outside the capacitor body 110. The outer electrodes 131 and 132 may include a first outer electrode 131 and a second outer electrode 132 provided at opposite ends of the capacitor body 110 in the length direction (L-axis direction).

[0048] For example, the capacitor body 110 may have a substantially hexahedral shape.

[0049] For ease of describing the embodiment, two surfaces facing each other in the thickness direction (T-axis direction) of the capacitor body 110 are referred to as a first surface and a second surface, two surfaces connected to the first surface and the second surface and facing each other in the length direction (L-axis direction) are referred to as a third surface and a fourth surface, and two surfaces connected to the first surface and the second surface and connected to the third surface and the fourth surface and facing each other in the width direction (W-axis direction) are referred to as a fifth surface and a sixth surface.

[0050] As an example, the first surface serving as the lower surface may be the mounting surface. Additionally, the first surface to the sixth surface may be flat, but the embodiments are not limited thereto. For example, the first surface to the sixth surface may be curved surfaces having convex central portions, and the edges serving as the boundaries of each surface may be rounded.

[0051] The shape and size of the capacitor body 110 and the number of stacked dielectric layers 111 are not limited to those shown in the drawings of the embodiments for the capacitor body and the number of stacked dielectric layers.

[0052] The capacitor body 110 includes a plurality of dielectric layers 111 and inner electrode layers (i.e., inner electrodes) 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and a first inner electrode 121 and a second inner electrode 122 that are alternately arranged in the thickness direction (T-axis direction) with the dielectric layer 111 interposed therebetween.

[0053] At this time, adjacent dielectric layers 111 of the capacitor body 110 may be integrated to such an extent that it is difficult to recognize the boundary between them without using a scanning electron microscope (SEM).

[0054] The capacitor body 110 may have an effective region. The effective region is the region where the dielectric layers 111 and the inner electrode layers 121 and 122 are alternately arranged, which contributes to forming the capacitance of the multilayer ceramic capacitor 100. Specifically, the effective region may be the region where the first inner electrode 121 and the second inner electrode 122 stacked along the thickness direction (T-axis direction) are superposed.

[0055] Additionally, the capacitor body 110 may further include a covering portion and a side edge portion.

[0056] The covering portion is the edge portion in the thickness direction and may be respectively located on the upper surface and the lower surface of the effective region in the thickness direction (T-axis direction). The covering portion may be a single dielectric layer or two or more dielectric layers respectively stacked on the upper surface and the lower surface of the effective region.

[0057] The side edge portion may be regarded as a side covering portion and may be respectively located on two side surfaces of the effective region that are opposite to each other in the width direction (W-axis direction). The side edge region may be formed in the following manner: when a conductive paste layer for the inner electrode is coated on the surface of the dielectric green sheet, dielectric green sheets that are coated with the conductive paste layer only in a partial region of the surface of the dielectric green sheet and are not coated with the conductive paste layer on two side edges of the surface of the dielectric green sheet are stacked and then fired, but the forming method is not limited thereto.

[0058] The covering portion and the side edge portion are used to prevent damage to the first inner electrode 121 and the second inner electrode 122 caused by physical stress or chemical stress.

[0059] The dielectric layer 111 may include at least one dielectric grain.

[0060] The dielectric grain may include a barium titanate-based main component containing barium (Ba) and titanium (Ti), and a sub-component.

[0061] The barium titanate-based main component is a dielectric matrix material with a high dielectric constant and contributes to forming the dielectric constant of the multilayer ceramic capacitor 100.

[0062] The barium titanate-based main component may include, for example, 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, (Ba, Sr)(Ti, Sn)O3, or a combination thereof.

[0063] The sub-component may include a first sub-component and a second sub-component. The first sub-component may be samarium (Sm), and the second sub-component may be a lanthanide element other than samarium (Sm). That is, the second sub-component may include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or a combination thereof.

[0064] For example, since the ionic radius of Sm 3+ is larger than that of Dy 3+ , it has a greater substitution efficiency as an A-site donor, the free electron emission effect increases, and the defect concentration control effect is excellent. In addition, compared with barium titanate doped with Dy, sufficient grain growth can occur in the case of barium titanate doped with Sm, enabling high capacitance to be achieved. Therefore, according to the embodiment, by including samarium (Sm) as the first sub-component in the dielectric grain, a multilayer ceramic capacitor with improved DC bias characteristics and reliability can be obtained. Here, the improvement of the DC bias characteristics means the improvement of the DC effective capacitance, which means that the degree of capacitance reduction when a DC voltage is applied is reduced.

[0065] Furthermore, according to the embodiment, since another lanthanide element as the second sub-component is included in the dielectric grain together with samarium (Sm) as the first sub-component, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be further improved.

[0066] Based on 100 atomic % of titanium (Ti), the amount of samarium (Sm) included in the dielectric grains can be in the range of 0.01 atomic % to 1.2 atomic %, for example, it can be in the range of 0.05 atomic % to 1.1 atomic % or 0.1 atomic % to 1.0 atomic %. When the samarium (Sm) included in the dielectric grains is within the above content range, a multilayer ceramic capacitor with excellent DC bias characteristics and reliability can be obtained.

[0067] The dielectric grains can have a core - shell structure including a core and a shell surrounding at least a part of the core. Samarium (Sm) can be included in both the core and the shell, and the atomic percentage of samarium (Sm) included in the shell can be higher than the atomic percentage of samarium (Sm) included in the core. Specifically, the atomic ratio of samarium (Sm) included in the shell to samarium (Sm) included in the core can be in the range of 1.2 to 2.5, for example, it can be in the range of 1.3 to 2.2 or 1.5 to 2.0. When the atomic percentage of samarium (Sm) in the shell is higher than that in the core, specifically, when the atomic ratio satisfies the above range, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be improved.

[0068] Among the above - mentioned lanthanide elements, the second sub - component can include, for example, terbium (Tb), dysprosium (Dy) or a combination thereof.

[0069] Based on 100 atomic % of titanium (Ti), the amount of the second sub - component included in the dielectric grains can be in the range of 1.2 atomic % to 2.0 atomic %, for example, it can be in the range of 1.3 atomic % to 1.9 atomic % or 1.4 atomic % to 1.8 atomic %. When the second sub - component includes two or more types of elements, the content of the second sub - component represents the total content of each element.

[0070] When the second sub - component included in the dielectric grains is within the above content range, a multilayer ceramic capacitor with excellent DC bias characteristics and reliability can be obtained.

[0071] The second sub - component can also be included in both the core and the shell, and the atomic % of the second sub - component included in the shell can be higher than the atomic % of the second sub - component included in the core. Specifically, the atomic ratio of the second sub - component included in the shell to the second sub - component included in the core can be in the range of 2 to 8, for example, it can be in the range of 3 to 7 or 4 to 6. When the atomic % of the second sub - component in the shell is higher than that in the core, specifically, when the atomic ratio satisfies the above range, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be improved.

[0072] The secondary component may further include a third secondary component. The third secondary component may include aluminum (Al), silicon (Si), magnesium (Mg), manganese (Mn), or a combination thereof. When the third secondary component is included in the dielectric grains together with samarium (Sm) as the first secondary component and another lanthanide element as the second secondary component, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be further improved.

[0073] Based on 100 atomic % of titanium (Ti), the amount of the third secondary component included in the dielectric grains may be in the range of 0.1 atomic % to 2.5 atomic %, for example, may be in the range of 1.0 atomic % to 2.5 atomic % or 1.4 atomic % to 2.5 atomic %. When the third secondary component included in the dielectric grains is within the above content range, a multilayer ceramic capacitor having excellent DC bias characteristics and reliability can be obtained.

[0074] As an example, the third secondary component may include aluminum (Al) and silicon (Si). In this case, the atomic ratio of samarium (Sm) to the sum of aluminum (Al) and silicon (Si) may be in the range of 0.01 to 0.7, for example, may be in the range of 0.05 to 0.7 or 0.1 to 0.7. When the atomic ratio satisfies the above range, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be improved.

[0075] Confirmation of samarium (Sm) as the first secondary component, another lanthanide element as the second secondary component, and an optional third secondary component included in the dielectric grains and their contents can be obtained by transmission electron microscope - energy dispersive X - ray spectrometer (TEM - EDS) analysis.

[0076] More specifically, after placing the multilayer ceramic capacitor 100 in an epoxy resin mixture and then curing it, the surfaces of the capacitor body 110 in the W-axis and T-axis directions (WT surfaces) are polished to a depth of 1 / 2 in the L-axis direction to obtain a cross-sectional sample. Then, the cross-sectional sample is fixed and held in a vacuum atmosphere chamber, so that the effective region where the dielectric layer 111 and the inner electrode layers 121 and 122 are alternately arranged can be observed. Subsequently, the effective region of this cross-sectional sample can be measured by a transmission electron microscope (TEM). For example, TEM analysis can be performed in a region of about 400 nm × 400 nm, where at least one layer in the dielectric layer 111 can be seen in the effective region by using a focused ion beam (Xe-FIB) under the condition of an acceleration voltage of 200 kV. Subsequently, in the TEM image of the measured cross-sectional sample, by performing EDS analysis on points in at least one dielectric grain within one dielectric layer (for example, points within one to ten dielectric grains or two to five dielectric grains), the content and arithmetic mean value of the elements can be obtained. Specifically, by performing EDS analysis on points in each core and shell of at least one dielectric grain having a core-shell structure (for example, points in each core and shell of one to ten dielectric grains having a core-shell structure or two to five dielectric grains having a core-shell structure), the content and arithmetic mean value of the elements in each of the core and shell can be obtained.

[0077] The diameter of the dielectric grains can be in the range of 100 nm to 500 nm based on the longest axis. For example, it can be in the range of 200 nm to 400 nm. When the diameter of the dielectric grains is within the above range, excellent insulation resistance (IR) can be maintained while achieving high capacitance. Therefore, a multilayer ceramic capacitor with excellent reliability can be obtained.

[0078] The average thickness of the dielectric layer 111 (the average length in the T-axis direction) can be in the range of 2.0 μm to 8.0 μm. For example, it can be in the range of 0.1 μm to 4.0 μm. When the average thickness of the dielectric layer 111 is within the above range, the reliability of the multilayer ceramic capacitor is excellent.

[0079] The average thickness of the dielectric layer 111 can be measured by placing the multilayer ceramic capacitor 100 in an epoxy resin mixture, then curing, polishing, and ion milling it, and analyzing it through a scanning electron microscope (SEM). For example, a Verios G4 product from Thermofisher Scientific can be used as the scanning electron microscope. The measurement conditions can be 10 kV and 0.2 nA, the analysis magnification can be 100 times, and measurements can be taken so that 1 layer or more, 3 layers or more, 5 layers or more, or 10 layers or more of the dielectric layer 111 can be obtained. In the scanning electron microscope (SEM) image, the center point of the dielectric layer 111 in the length direction (L-axis direction) or width direction (W-axis direction) is taken as the reference point, and the arithmetic mean of the thickness of the dielectric layer 111 can be obtained for 10 points set at a predetermined interval from the reference point. The interval between adjacent points among the 10 points can be adjusted according to the scale of the SEM image. For example, it can be 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm. At this time, all 10 points must be located within the dielectric layer 111, and if not all 10 points are located within the dielectric layer 111, the position of the reference point can be changed, or the interval between adjacent points among the 10 points can be adjusted.

[0080] The first internal electrode 121 and the second internal electrode 122 are electrodes with different polarities, which are alternately arranged facing each other along the T-axis direction with the dielectric layer 111 therebetween, and may respectively have ends alternately exposed through the third surface and the fourth surface of the capacitor body 110.

[0081] The first internal electrode 121 and the second internal electrode 122 can be electrically insulated from each other by the dielectric layer 111 provided therebetween.

[0082] The ends of the first internal electrode 121 and the second internal electrode 122 alternately exposed through the third surface and the fourth surface of the capacitor body 110 can be electrically connected to the first external electrode 131 and the second external electrode 132 respectively.

[0083] The first internal electrode 121 and the second internal electrode 122 can include a conductive metal, such as metals like Ni, Cu, Ag, Pd, Au, or their alloys (such as Ag-Pd alloy).

[0084] In addition, the first internal electrode 121 and the second internal electrode 122 can include dielectric grains having the same composition as the ceramic material included in the dielectric layer 111.

[0085] The first internal electrode 121 and the second internal electrode 122 can be formed using a conductive paste including a conductive metal. The printing method of the conductive paste can be a screen printing method or a gravure printing method.

[0086] The average thickness of the first internal electrode 121 and the second internal electrode 122 can be in the range of 0.1 μm to 2 μm. The average thickness of the first internal electrode 121 and the second internal electrode 122 can be measured by SEM analysis. Here, since the SEM analysis is the same as the SEM analysis in the above method for measuring the average thickness of the dielectric layer 111, the description thereof will be omitted.

[0087] The capacitor body 110 can be formed by firing a stacked structure in which a plurality of dielectric layers 111 and internal electrode layers 121 and 122 are stacked.

[0088] The first external electrode 131 and the second external electrode 132 provide voltages of different polarities and can be electrically connected to the exposed portions of the first internal electrode 121 and the second internal electrode 122, respectively.

[0089] According to the above structure, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charges accumulate between the first internal electrode 121 and the second internal electrode 122 facing each other. At this time, the capacitance of the multilayer ceramic capacitor 100 is proportional to the overlapping area of the first internal electrode 121 and the second internal electrode 122 stacked along the T-axis direction in the effective region.

[0090] The first external electrode 131 can include a first connection portion provided on the third surface of the capacitor body 110 and connected to the first internal electrode 121, and a first band portion provided on the edge where the third surface of the capacitor body 110 intersects with the first surface, the second surface, the fifth surface, and the sixth surface. The second external electrode 132 can include a second connection portion provided on the fourth surface of the capacitor body 110 and connected to the second internal electrode 122, and a second band portion provided on the edge where the fourth surface of the capacitor body 110 intersects with the first surface, the second surface, the fifth surface, and the sixth surface.

[0091] The first band portion and the second band portion can extend from the first connection portion and the second connection portion to a part of the first surface and a part of the second surface of the capacitor body 110, respectively, and can also extend from the first connection portion and the second connection portion to a part of the fifth surface and a part of the sixth surface of the capacitor body 110, respectively. The first band portion and the second band portion can be used to improve the adhesion strength between the first external electrode 131 and the second external electrode 132 and the capacitor body 110.

[0092] Each of the first external electrode 131 and the second external electrode 132 can include a sintered metal layer in contact with the capacitor body 110, a conductive resin layer provided to cover the sintered metal layer, and a plating layer provided to cover the conductive resin layer.

[0093] The sintered metal layer can include a conductive metal and glass.

[0094] 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 their alloys. For example, the conductive metal including copper (Cu) may mean that the conductive metal includes elemental copper (Cu) or a copper (Cu) alloy. When the conductive metal includes copper (Cu), the amount of the metal other than copper (Cu) included may be 5 mole parts or less relative to 100 mole parts of copper (Cu).

[0095] The glass may include a composition of mixed oxides. For example, the glass may include one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides, and alkaline earth metal oxides. The transition metal may be selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni). The alkali metal may be selected from the group consisting of lithium (Li), sodium (Na), and potassium (K). The alkaline earth metal may be at least one selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0096] Optionally, a conductive resin layer may be formed on the sintered metal layer. For example, it may be formed in a shape that completely covers the sintered metal layer. In addition, the first external electrode 131 and the second external electrode 132 may not include a sintered metal layer. In this case, the conductive resin layer may be in direct contact with the capacitor body 110.

[0097] The conductive resin layer extends to the first surface and the second surface of the capacitor body 110, and may also extend to the fifth surface and the sixth surface of the capacitor body 110. Moreover, the length of the region (i.e., the belt portion) where the conductive resin layer extends and is provided on the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110 may be longer than the length of the region (i.e., the belt portion) where the sintered metal layer extends and is provided on the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110. That is to say, 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.

[0098] The conductive resin layer may include a resin and a conductive metal.

[0099] The resin included in the conductive resin layer may be realized by a material having adhesiveness and shock absorbency and capable of forming a paste when mixed with conductive metal powder, but is not limited thereto. For example, the resin may include a phenolic resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

[0100] The conductive metal included in the conductive resin layer is used to electrically connect the first inner electrode 121 and the second inner electrode 122 or the sintered metal layer to the plating layer described below.

[0101] The conductive metal included in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof. That is, the conductive metal may be formed only in a flake shape, only in a spherical shape, or in a mixed form of a flake shape and a spherical shape.

[0102] Here, the spherical shape may also include a shape that is not a perfect spherical shape. For example, a shape having a length ratio of the major axis to the minor axis (major axis / minor axis) of 1.45 or less. The flake shape refers to a flat and elongated shape and is not particularly limited. However, for example, the length ratio of the major axis to the minor axis (major axis / minor axis) may be 1.95 or more.

[0103] The first outer electrode 131 and the second outer electrode 132 may further include a plating layer provided outside the conductive resin layer.

[0104] The plating layer 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 a combination thereof, or an alloy thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, may be in a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are stacked in sequence, or may be in a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer are stacked in sequence. Additionally, the plating layer may include multiple nickel (Ni) plating layers and / or multiple tin (Sn) plating layers.

[0105] The plating layer can improve the mountability on a substrate, the structural reliability, the durability against the outside, the heat resistance, and the equivalent series resistance (ESR) of the multilayer ceramic capacitor 100.

[0106] Hereinafter, a method for manufacturing the multilayer ceramic capacitor 100 according to an embodiment will be described.

[0107] The multilayer ceramic capacitor 100 according to an embodiment can be manufactured by the following steps: preparing a dielectric paste by mixing a barium titanate-based main component powder and a sub-component powder, the sub-component powder including a samarium (Sm)-containing compound and a second sub-component compound; manufacturing a dielectric green sheet using the dielectric paste and forming a conductive paste layer on the surface of the dielectric green sheet; manufacturing a dielectric green sheet laminate by stacking the dielectric green sheets having the conductive paste layer formed thereon; manufacturing a capacitor body including a dielectric layer and an inner electrode layer by firing the dielectric green sheet laminate; and forming outer electrodes on the surface of the capacitor body.

[0108] First, a dielectric paste is prepared by mixing a barium titanate-based main component powder and a sub-component powder.

[0109] The barium titanate-based main component powder can be prepared by mixing a titanium (Ti) precursor and a barium (Ba) precursor.

[0110] The titanium (Ti) precursor can be an oxide, salt, alkoxide, etc. of titanium. For example, it can include titanium dioxide, titanium diisopropoxide bis(acetylacetonate) (TPA), titanium alkoxide, or a combination thereof. The barium (Ba) precursor can include BaO2, BaTiO3, BaCO3, BaO, or a combination thereof.

[0111] Based on 1 mole of the titanium (Ti) precursor, the amount of the barium (Ba) precursor included can be in the range of 0.9 moles to 1.1 moles.

[0112] The sub-component powder can include a samarium (Sm)-containing compound and a second sub-component compound.

[0113] The samarium (Sm)-containing compound can be an oxide, nitride, or salt compound, and / or can be in the form of a sol dispersed in an organic solvent.

[0114] Based on 100 parts by mole of the barium titanate-based main component powder, the amount of samarium (Sm) in the mixed samarium (Sm)-containing compound can be in the range of 0.01 part by mole to 1.2 parts by mole. For example, the amount of samarium (Sm) in the mixed samarium (Sm)-containing compound can be in the range of 0.1 part by mole to 1.0 part by mole. When the samarium (Sm) in the mixed samarium (Sm)-containing compound is within the above content range, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be improved.

[0115] The second sub-component compound can include a lanthanum (La)-containing compound, a cerium (Ce)-containing compound, a praseodymium (Pr)-containing compound, a neodymium (Nd)-containing compound, a promethium (Pm)-containing compound, a europium (Eu)-containing compound, a gadolinium (Gd)-containing compound, a terbium (Tb)-containing compound, a dysprosium (Dy)-containing compound, a holmium (Ho)-containing compound, an erbium (Er)-containing compound, a thulium (Tm)-containing compound, a ytterbium (Yb)-containing compound, a lutetium (Lu)-containing compound, or a combination thereof. As an example, the second sub-component compound can include a terbium (Tb)-containing compound, a dysprosium (Dy)-containing compound, or a combination thereof.

[0116] The second sub-component compound can be an oxide, nitride, or salt compound, and / or can be in the form of a sol dispersed in an organic solvent.

[0117] Based on 100 moles of the barium titanate-based main component powder, the amount of the second sub-component in the mixed second sub-component-containing compound can be in the range of 1.2 moles to 2.0 moles. For example, the amount of the second sub-component in the mixed second sub-component-containing compound can be in the range of 1.4 moles to 1.8 moles. When the second sub-component in the mixed second sub-component-containing compound is within the above content range, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be improved.

[0118] The sub-component powder may further include a third sub-component-containing compound.

[0119] The third sub-component-containing compound may include an aluminum (Al)-containing compound, a silicon (Si)-containing compound, a magnesium (Mg)-containing compound, a manganese (Mn)-containing compound, or a combination thereof. As an example, the third sub-component-containing compound may include an aluminum (Al)-containing compound and a silicon (Si)-containing compound.

[0120] The third sub-component-containing compound may be an oxide, a nitride, or a salt compound, and / or may be in the form of a sol dispersed in an organic solvent.

[0121] Based on 100 moles of the barium titanate-based main component powder, the amount of the third sub-component in the mixed third sub-component-containing compound can be in the range of 0.1 mole to 2.5 moles. For example, the amount of the third sub-component in the mixed third sub-component-containing compound can be in the range of 1.4 moles to 2.5 moles. When the third sub-component in the mixed third sub-component-containing compound is within the above content range, the DC bias characteristics and reliability of the multilayer ceramic capacitor can be improved.

[0122] In addition to the obtained dielectric material powder, a dielectric paste can be prepared by further mixing a solvent and additives such as a dispersant, a binder, a plasticizer, a lubricant, and an antistatic agent.

[0123] The dispersant may include, for example, a phosphate-based dispersant, a polycarboxylic acid-based dispersant, or a combination thereof. Based on 100 parts by weight of the barium titanate-based main component powder, the amount of the mixed dispersant can be in the range of 0.1 part by weight to 5 parts by weight. For example, the amount of the mixed dispersant can be in the range of 0.3 part by weight to 3 parts by weight. When the mixed dispersant is within the above content range, the dielectric paste exhibits excellent dispersibility, and the amount of impurities included in the manufactured dielectric layer can be reduced.

[0124] The binder can be, for example, an acrylic resin, a polyvinyl butyral resin, a polyvinyl acetal resin, an ethyl cellulose resin, etc. Based on 100 parts by weight of the barium titanate-based main component powder, the amount of the added binder can be from 0.1 part by weight to 50 parts by weight, for example, from 3 parts by weight to 30 parts by weight. When the mixed binder is within the above content range, the dielectric slurry exhibits excellent dispersibility, and the amount of impurities included in the manufactured dielectric layer can be reduced.

[0125] The plasticizer can be, for example: phthalic acid compounds such as dioctyl phthalate, butyl benzyl phthalate, dibutyl phthalate, dihexyl phthalate, bis(2-ethylhexyl) phthalate, and bis(2-ethylbutyl) phthalate; adipic acid compounds such as dihexyl adipate and bis(2-ethylhexyl) adipate; ethylene glycol compounds such as ethylene glycol, diethylene glycol, and triethylene glycol; ethylene glycol ester compounds such as triethylene glycol dibutyrate, triethylene glycol bis(2-ethylbutyrate), and triethylene glycol bis(2-ethylhexanoate), etc. Based on 100 parts by weight of the barium titanate-based main component powder, the amount of the added plasticizer can be from 0.1 part by weight to 20 parts by weight, for example, from 1 part by weight to 10 parts by weight. When the mixed plasticizer is within the above content range, the dielectric slurry exhibits excellent dispersibility, and the amount of impurities included in the manufactured dielectric layer can be reduced.

[0126] The solvent can be: an aqueous solvent such as water; an alcohol solvent such as ethanol, methanol, benzyl alcohol, and methoxyethanol; an ethylene glycol solvent such as ethylene glycol and diethylene glycol; a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; an ester solvent such as butyl acetate, ethyl acetate, carbitol acetate, and butyl carbitol acetate; an ether solvent such as methyl cellosolve, ethyl cellosolve, butyl ether, and tetrahydrofuran; an aromatic solvent such as benzene, toluene, and xylene, etc. Considering the solubility or dispersibility of various additives included in the dielectric slurry, the solvent can be, for example, an alcohol solvent or an aromatic solvent. Based on 100 parts by weight of the barium titanate-based main component powder, the amount of the mixed solvent can be from 50 parts by weight to 1000 parts by weight, for example, it can be from 100 parts by weight to 500 parts by weight. When the mixed solvent is within the above content range, the dielectric slurry components can be fully mixed, and the solvent can be easily removed subsequently.

[0127] The above dielectric slurry can be mixed by using a wet ball mill or a stirring mill. When using zirconia balls in a wet ball mill, a plurality of zirconia balls with a diameter of 0.1 mm to 10 mm can be used for wet mixing for a period of 8 hours to 48 hours or 10 hours to 24 hours.

[0128] The prepared dielectric slurry forms a dielectric layer after firing.

[0129] As a method of forming the dielectric paste to be prepared into a sheet shape, tape forming methods such as the doctor blade method and the casting roll method can be used. For example, a coating head discharge type roll coater can be used, and a dielectric green sheet can be obtained by drying the formed body afterwards.

[0130] To form a conductive paste layer that becomes an internal electrode layer after firing, a conductive paste can be prepared by mixing a conductive powder (made of a conductive metal or their alloy), a binder, and a solvent. Additionally, if necessary, barium titanate powder can be mixed together as a co-material. The co-material can function to inhibit the sintering of the conductive powder during the firing process. The conductive paste is coated on the surface of the dielectric green sheet in a predetermined pattern by using various printing methods such as the screen printing method or a transfer method to form a conductive paste layer.

[0131] The conductive powder can include nickel (Ni) or a nickel (Ni) alloy.

[0132] Next, a dielectric green sheet laminate is prepared by stacking multilayer dielectric green sheets on which internal electrode patterns are formed, and then pressing the multilayer dielectric green sheets in the stacking direction. At this time, dielectric green sheets without internal electrode patterns can be stacked such that the dielectric green sheets without internal electrode patterns are respectively located on the upper surface and the lower surface of the dielectric green sheet laminate in the stacking direction.

[0133] The step of cutting the prepared dielectric green sheet laminate into a predetermined size by cutting or the like can be optionally performed.

[0134] Additionally, if necessary, the dielectric green sheet laminate can be cured and dried to remove plasticizers and the like, and after curing and drying, the dielectric green sheet laminate can be polished using a horizontal centrifugal drum machine or the like. During drum polishing, the dielectric green sheet laminate is placed in a drum container together with a medium and a polishing liquid, and a rotational motion or vibration is applied to the drum container, so that unnecessary parts (such as burrs generated during cutting) can be polished. Additionally, after drum polishing, the dielectric green sheet laminate can be cleaned with a cleaning solution such as water and dried.

[0135] Subsequently, a capacitor body can be prepared after performing an adhesive removal treatment and firing the dielectric green sheet laminate.

[0136] The conditions of the adhesive removal treatment can be appropriately adjusted according to the composition of the dielectric layer or the internal electrode layer. For example, the heating rate during the adhesive removal treatment can be in the range of 5 °C / hour to 300 °C / hour, the holding temperature can be in the range of 180 °C to 400 °C, and the temperature holding time can be in the range of 0.5 hour to 24 hours. The adhesive removal can be performed in an air atmosphere or a reducing atmosphere.

[0137] The firing treatment conditions can be appropriately adjusted according to the main component composition of the dielectric layer or the main component composition of the inner electrode. For example, firing can be carried out at a temperature in the range of 1100°C to 1400°C, for example, at a temperature in the range of 1200°C to 1350°C. Additionally, firing can be carried out for a period of 0.5 hours to 8 hours (for example, 1 hour to 3 hours). Further, firing can be carried out in a reducing atmosphere, for example, in a humidified mixed gas of nitrogen and hydrogen. When the inner electrode includes nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere can be in the range of 1.0×10 -14 MPa to 1.0×10 -10 MPa.

[0138] After firing, annealing can be carried out as needed. Annealing is a treatment for re-oxidizing the dielectric layer, and if firing is carried out in a reducing atmosphere, annealing can be carried out. The annealing treatment conditions can also be appropriately adjusted according to the composition of the dielectric layer. For example, the annealing temperature can be in the range of 950°C to 1150°C, the time can be in the range of 0 to 20 hours, and the heating rate can be in the range of 50°C / hour to 500°C / hour. The annealing atmosphere can be a humidified nitrogen (N2) atmosphere, and the oxygen partial pressure can be in the range of 1.0×10 -9 MPa to 1.0×10 -5 MPa.

[0139] During the binder removal treatment, firing treatment, or annealing treatment, for example, a wetting agent can be used to humidify nitrogen or the mixed gas. In this case, the wetting agent temperature can be in the range of 5°C to 75°C. The binder removal treatment, firing treatment, and annealing treatment can be carried out sequentially or independently.

[0140] Optionally, surface treatments (such as sandblasting, laser irradiation, barrel polishing, etc.) can be performed on the third surface and the fourth surface of the prepared capacitor body 110. By performing this surface treatment, the ends of the first inner electrode and the second inner electrode can be respectively exposed to the third surface and the fourth surface, so the electrical connection between the first outer electrode and the first inner electrode and between the second outer electrode and the second inner electrode can be improved, and the alloy part can be easily formed.

[0141] Subsequently, an outer electrode is formed on the surface of the manufactured capacitor body 110.

[0142] As an example, a paste for forming a sintered metal layer can be coated on the outer electrode and then sintered to form a sintered metal layer.

[0143] The paste for forming a sintered metal layer may include a conductive metal and glass. Since the descriptions of the conductive metal and glass are the same as those above, the repeated descriptions will be omitted. Additionally, the paste for forming a sintered metal layer may optionally include a binder, a solvent, a dispersant, a plasticizer, an oxide powder, etc. The binder may be, for example, ethyl cellulose, an acrylic resin, a butyral resin, etc., and the solvent may be an organic solvent (such as an alcohol (e.g., terpineol, butyl carbitol), methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0144] The method of coating the paste for forming a sintered metal layer on the outer surface of the capacitor body 110 may include various printing methods (such as a screen printing method), an impregnation method, a coating method using a dispenser, etc., and a spraying method using an injector. The paste for forming a sintered metal layer may be coated on at least one of the third surface and the fourth surface of the capacitor body 110, and optionally on a portion of the first surface, the second surface, the fifth surface, or the sixth surface that will form the strip portions of the first outer electrode and the second outer electrode.

[0145] Thereafter, the capacitor body 110 coated with the paste for forming a sintered metal layer is dried and sintered for a period within the range of 0.1 hour to 3 hours at a temperature within the range of 700 °C to 1000 °C to form a sintered metal layer.

[0146] Optionally, the paste for forming a conductive resin layer is coated on the outer surface of the obtained capacitor body 110 and then cured to form a conductive resin layer.

[0147] The paste for forming a conductive resin layer may include a resin and a conductive metal, and optionally, may include a non-conductive filler. Since the descriptions of the conductive metal and the resin are the same as those above, the repeated descriptions will be omitted. Additionally, the paste for forming a conductive resin layer may optionally include a binder, a solvent, a dispersant, a plasticizer, an oxide powder, etc. The binder may be, for example, ethyl cellulose, an acrylic resin, a butyral resin, etc., and the solvent may be an organic solvent (such as an alcohol (e.g., terpineol, butyl carbitol), methyl ethyl ketone, acetone, and toluene) or an aqueous solvent.

[0148] For example, the conductive resin layer may be formed by dipping the capacitor body 110 in the paste for forming a conductive resin layer and then curing it, or by printing the paste for forming a conductive resin layer on the surface of the capacitor body 110 by a screen printing method or a gravure printing method, or by coating the paste for forming a conductive resin layer on the surface of the capacitor body 110 and then curing it.

[0149] Next, a plating layer is formed on the outside of the conductive resin layer.

[0150] For example, the coating layer can be formed by plating, sputtering, or electrolytic plating (electrodeposition).

[0151] The above embodiments will be described in more detail by way of examples below. However, the following examples are for illustrative purposes only and do not limit the scope of the appended claims.

[0152] (Manufacture of multilayer ceramic capacitor) Examples 1 to 8 and Comparative Examples 1 to 7 According to the composition in Table 1 below, a dielectric paste is prepared by mixing barium titanate (BaTiO3) as the main component powder and samarium oxide (Sm2O3), dysprosium oxide (Dy2O3), terbium oxide (Tb4O7), alumina (Al2O3), and silicon dioxide (SiO2) as the sub-component powders. The mixing is carried out by using zirconia balls (ZrO2 balls) as the dispersion medium, where ethanol / toluene and polyvinyl butyral (PVB) resin are added together as the wetting dispersant and binder and mechanically ground.

[0153] A dielectric green sheet is prepared by coating the dielectric paste using a coating head discharge type roll-on former coater.

[0154] A conductive paste layer including nickel (Ni) is printed on the surface of the dielectric green sheet, and the dielectric green sheets with the conductive paste layer formed thereon are stacked and pressed to prepare a dielectric green sheet laminate.

[0155] The dielectric green sheet laminate is subjected to a firing process at a temperature of 400 °C or lower in a nitrogen atmosphere, and then the dielectric green sheet laminate is fired at a firing temperature of 1300 °C or lower and a hydrogen concentration of 1.0% H2 or lower.

[0156] Subsequently, an external electrode is formed by a process such as plating, thereby manufacturing a multilayer ceramic capacitor.

[0157] (Table 1) The unit of the content of each component is expressed in mole parts based on 100 mole parts of the main component powder of barium titanate (BaTiO3), and the content of each component represents the content value of the element (corresponding sub-component) in the corresponding oxide or the content ratio between the elements (corresponding sub-components).

[0158]

[0159] Evaluation 1: TEM-EDS analysis The multilayer ceramic capacitors manufactured in Examples 1 to 8 and Comparative Examples 1 to 7 were subjected to transmission electron microscope-energy dispersive X-ray spectrometer (TEM-EDS) analysis, and the results are shown in Table 2 and Table 3 below and Figures 4 to 6 in.

[0160] The TEM-EDS analysis was performed as follows. After placing the multilayer ceramic capacitors fabricated in Examples 1 to 8 and Comparative Examples 1 to 7 in an epoxy resin mixture and curing, the surfaces of the capacitor body 110 in the W-axis and T-axis directions (WT surfaces) were polished to a depth of 1 / 2 in the L-axis direction to obtain a cross-sectional sample. Then, the cross-sectional sample was fixed and held in a vacuum atmosphere chamber, so that the effective region where the dielectric layer and the internal electrode layer were alternately arranged could be observed. The effective region of this cross-sectional sample was measured by using TEM. The TEM analysis can be performed in a region of about 400 nm × 400 nm, where at least one layer in the dielectric layer 111 can be seen in the effective region by using a focused ion beam (Xe-FIB) under the condition of an acceleration voltage of 200 kV.

[0161] In the TEM image of the measured cross-sectional sample, the contents of Sm, Dy, and Tb present in the dielectric grains were confirmed by EDS line analysis. Specifically, as Figure 4 shown, for the line segment connected by a straight line from the starting point to the ending point of the dielectric grain, the atomic percentage of each component was confirmed.

[0162] Figure 4 is a low-magnification TEM image of the dielectric layer according to Example 1. Figure 5 is regarding Figure 4 the EDS line analysis diagram of the dielectric grains shown in

[0163] Referring to Figure 5 , the relative atomic percentages of Sm, Dy, and Tb can be confirmed, and it can be seen that the concentration of samarium (Sm) tends to increase in the shell region compared to the core.

[0164] Figure 6 is a high-magnification TEM image of the dielectric layer according to Example 1.

[0165] In addition, in the transmission electron microscope (TEM) image of the measured cross-sectional sample of Example 1, as Figure 6 shown, for three dielectric grains in one dielectric layer, EDS analysis was performed at the points in the core and the shell in each dielectric grain. By EDS analysis, the arithmetic mean of the atomic percentages of the O, Ti, Dy, and Sm components at the points in the three cores and the arithmetic mean of the atomic percentages of the O, Ti, Dy, and Sm components at the points in the three shells were obtained, and the results are shown in Table 2 below.

[0166] (Table 2) The unit is the atomic percentage based on the total amount of elements at each point.

[0167]

[0168] From Table 2, it can be seen that in Example 1, in the region of the shell, samarium (Sm) and dysprosium (Dy) have higher atomic percentages, i.e., higher concentrations, compared to the core.

[0169] Evaluation 2: Reliability The dielectric constant, MTTF, and insulation resistance (IR) levels were measured for the multilayer ceramic capacitors fabricated in Examples 1 to 8 and Comparative Examples 1 to 7, and the results are shown in Table 3 below.

[0170] The dielectric constant was measured under the conditions of 1 kHz and 0.5 V.

[0171] The mean time to failure (MTTF) was measured under the conditions of a temperature of 125 °C and a voltage of 9.45 V to obtain the mean time to failure (hours) at which failure occurred. In Table 3 below, ○ indicates a mean time to failure of 11 hours or longer, and X indicates a mean time to failure of less than 11 hours.

[0172] When measuring the high-temperature harsh reliability using an ESPEC (PV-222, HALT) device under the conditions of 125 °C, 9.45 V, and 48 hours, the insulation resistance (IR) level can be obtained.

[0173] (Table 3) The unit of the content of each component is the atomic percentage based on 100 atomic% of titanium (Ti).

[0174]

[0175] From Table 3, it can be seen that in Examples 1 to 8 in which the dielectric grains according to the embodiments include samarium (Sm) as the first sub-component and second sub-components such as dysprosium (Dy) and terbium (Tb) and all the second sub-components satisfy a predetermined range of atomic percentages, the dielectric constant, MTTF, and insulation resistance (IR) levels are all excellent compared to Comparative Examples 1 to 7.

[0176] In addition, the multilayer ceramic capacitors fabricated in Example 3, Example 5, and Comparative Example 1 were prepared in groups of 40 and mounted on a measurement substrate, and the high-temperature harsh reliability was measured using an ESPEC (PV-222, HALT) device under the conditions of 125 °C, 9.45 V, and 48 hours, and the results are shown in Figures 7 to 9 in.

[0177] Figure 7 is a graph showing the high-temperature harsh reliability of the multilayer ceramic capacitor according to Comparative Example 1. Figure 8 is a graph showing the high-temperature harsh reliability of the multilayer ceramic capacitor according to Example 3. Figure 9It is a graph showing the high-temperature severe reliability of the multilayer ceramic capacitor according to Example 5.

[0178] Referring to Figures 7 to 9 , it can be seen that, compared with Comparative Example 1, Examples 3 and 5 in which the dielectric grains according to the embodiments include samarium (Sm) as the first sub-component and second sub-components such as dysprosium (Dy) and terbium (Tb) and all the second sub-components have atomic percentages within a predetermined range can provide excellent high-temperature severe reliability.

[0179] Although the present disclosure has been described in connection with presently considered practical embodiments, it will be understood that the present disclosure is not limited to the disclosed embodiments, but on the contrary, the present disclosure is intended to cover various modifications and equivalent schemes included within the spirit and scope of the appended claims.

[0180] <Explanation of Reference Numerals> 100: Multilayer ceramic capacitor 110: Capacitor body 111: Dielectric layer 121: First internal electrode 122: Second internal electrode 131: First external electrode 132: Second external electrode.

Claims

1. A multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and an inner electrode layer; as well as An external electrode, disposed outside the capacitor body, Wherein, the dielectric layer includes at least one dielectric grain, The dielectric grains include a barium titanate-based main component including Ba and Ti and a secondary component, The subcomponent includes Sm as a first subcomponent and a second subcomponent, wherein the second subcomponent includes La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a combination thereof, and Here, an amount of the second subcomponent included in the dielectric grains is in a range of 1.2 atomic % to 2.0 atomic % based on 100 atomic % of Ti.

2. The multilayer ceramic capacitor according to claim 1, wherein: The second auxiliary component includes Tb, Dy or a combination thereof.

3. The multilayer ceramic capacitor of claim 1, wherein: The dielectric grain includes a core and a shell surrounding at least a portion of the core, The second subcomponent is included in the core and the shell, and An atomic percentage of the second subcomponent included in the shell is higher than an atomic percentage of the second subcomponent included in the core.

4. The multilayer ceramic capacitor according to claim 3, wherein: An atomic ratio of the second subcomponent included in the shell to the second subcomponent included in the core is in a range of 2 to 8.

5. The multilayer ceramic capacitor according to claim 1, wherein: The amount of Sm included in the dielectric grains is in the range of 0.01 atomic % to 1.2 atomic % based on 100 atomic % of Ti.

6. The multilayer ceramic capacitor of claim 1, wherein: The dielectric grain includes a core and a shell surrounding at least a portion of the core; Sm is included in the core and the shell; and The atomic percentage of Sm included in the shell is higher than the atomic percentage of Sm included in the core.

7. The multilayer ceramic capacitor according to claim 6, wherein: An atomic ratio of Sm included in the shell to Sm included in the core is in the range of 1.2 to 2.

5.

8. The multilayer ceramic capacitor according to claim 1, wherein: The subcomponents further include a third subcomponent, and the third subcomponent includes Al, Si, Mg, Mn or a combination thereof.

9. The multilayer ceramic capacitor according to claim 8, wherein: An amount of the third subcomponent included in the dielectric grains is in a range of 0.1 atomic % to 2.5 atomic % based on 100 atomic % of Ti.

10. The multilayer ceramic capacitor according to claim 8, wherein The third subcomponent includes Al and Si.

11. The multilayer ceramic capacitor according to claim 10, wherein: The atomic ratio of Sm to the sum of Al and Si is in the range of 0.01 to 0.

7.

12. The multilayer ceramic capacitor according to claim 8, wherein: The diameter of the dielectric grains is in the range of 100 nm to 500 nm based on the longest axis.

13. A method for manufacturing a multilayer ceramic capacitor, the method comprising: preparing a dielectric slurry by mixing a barium titanate-based main component powder and a subsidiary component powder, the subsidiary component powder comprising a Sm-containing compound and a second subsidiary component compound; manufacturing a dielectric green sheet by using the dielectric slurry, and forming a conductive paste layer on a surface of the dielectric green sheet; manufacturing a dielectric green sheet laminate by stacking the dielectric green sheets on which the conductive paste layers are formed; manufacturing a capacitor body including a dielectric layer and an internal electrode layer by firing the dielectric green sheet laminate; and forming external electrodes on a surface of the capacitor body, The second subcomponent-containing compound includes a La-containing compound, a Ce-containing compound, a Pr-containing compound, a Nd-containing compound, a Pm-containing compound, a Eu-containing compound, a Gd-containing compound, a Tb-containing compound, a Dy-containing compound, a Ho-containing compound, an Er-containing compound, a Tm-containing compound, a Yb-containing compound, a Lu-containing compound or a combination thereof, and Here, an amount of the second subcomponent in the second subcomponent-containing compound included in the dielectric slurry is in a range of 1.2 parts by mole to 2.0 parts by mole based on 100 parts by mole of the barium titanate-based main component powder.

14. The manufacturing method according to claim 13, wherein: The second subcomponent-containing compound includes a Tb-containing compound, a Dy-containing compound, or a combination thereof.

15. The manufacturing method according to claim 13, wherein: An amount of Sm in the Sm-containing compound included in the dielectric slurry is in the range of 0.01 parts by mole to 1.2 parts by mole based on 100 parts by mole of the barium titanate-based main component powder.

16. The manufacturing method according to claim 13, wherein: The auxiliary component powder further includes a third auxiliary component-containing compound, and the third auxiliary component-containing compound includes an Al-containing compound, a Si-containing compound, a Mg-containing compound, a Mn-containing compound, or a combination thereof.

17. The manufacturing method according to claim 16, wherein: An amount of the third subcomponent in the third subcomponent-containing compound included in the dielectric slurry is in the range of 0.1 parts by mole to 2.5 parts by mole based on 100 parts by mole of the barium titanate-based main component powder.

18. The manufacturing method according to claim 16, wherein: The third subcomponent-containing compound includes the Al-containing compound and the Si-containing compound.

19. A dielectric material having dielectric grains, comprising: Main components include barium titanate-based compounds; A subcomponent includes a first subcomponent and a second subcomponent, the first subcomponent includes Sm, and the second subcomponent includes a metal selected from the group consisting of La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and a combination thereof, Here, an amount of the second subcomponent included in the dielectric material is in a range of 1.2 atomic % to 2.0 atomic % based on 100 atomic % of Ti.

20. The dielectric material of claim 19, wherein The dielectric grain includes a core and a shell surrounding at least a portion of the core, the core and the shell both include the second subcomponent, and an atomic percentage of the second subcomponent included in the shell is higher than an atomic percentage of the second subcomponent included in the core.

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