Multilayer ceramic capacitor and method of manufacturing the same

Abstract

The invention provides a multilayer ceramic capacitor and a method of manufacturing the same. The multilayer ceramic capacitor includes: a capacitor body including a dielectric layer and an inner electrode; and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric grains including a core portion and a shell portion surrounding at least a portion of the core portion, the shell portion including a barium titanate-based principal component including barium (Ba) and titanium (Ti), and a rare earth element (R) including dysprosium (Dy), terbium (Tb), yttrium (Y), lanthanum (La), or a combination thereof, the coefficient of variation (CV) of the atomic ratio of R / Ba and the coefficient of variation (CV) of the atomic ratio of R / Ti in the shell part are both greater than 0 and less than 0.19.

Description

Technical Field

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

[0002] Electronic components using ceramic materials include capacitors, inductors, piezoelectric elements, varistors, thermistors, etc. Multilayer ceramic capacitors (MLCCs) among ceramic electronic components can be used in various electronic devices due to their advantages of small size, high capacity, and easy installation.

[0003] For example, multilayer ceramic capacitors (MLCCs) can be mounted on substrates of various electronic products such as imaging devices (such as liquid crystal displays (LCDs), plasma display panels (PDPs), organic light emitting diodes (OLEDs), etc.), computers, personal portable terminals, and smart phones, so that the multilayer ceramic capacitors (MLCCs) function as chip capacitors that function to charge or discharge therefrom.

[0004] MLCCs have recently become thinner as they become highly integrated, and high reliability needs to be ensured with a thin layer design. Summary of the invention

[0005] The present disclosure provides a multilayer ceramic capacitor having excellent reliability and dispersion characteristics.

[0006] Another embodiment of the present disclosure provides a method of manufacturing a multilayer ceramic capacitor.

[0007] According to some embodiments, a multilayer ceramic capacitor includes: a capacitor body including a dielectric layer and an inner electrode; and an outer electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric grains, at least one of the plurality of dielectric grains includes a core and a shell surrounding at least a portion of the core, the shell including a barium titanate-based main component and a rare earth element (R), the barium titanate-based main component including barium (Ba) and titanium (Ti), the rare earth element (R) including at least one selected from the group consisting of dysprosium (Dy), terbium (Tb), yttrium (Y) and lanthanum (La), and the coefficient of variation (CV) of the atomic ratio of R / Ba and the coefficient of variation (CV) of the atomic ratio of R / Ti in the shell are both greater than 0 and less than 0.19.

[0008] Coefficient of variation of atomic ratio (CV) = [sample standard deviation (σ) of atomic ratio / average value of atomic ratio]. The rare earth element in the shell portion may include dysprosium (Dy), and the coefficient of variation of the atomic ratio of Dy / Ba and the coefficient of variation of the atomic ratio of Dy / Ti in the shell portion may both be greater than 0 and less than 0.19.

[0009] The atomic ratio of R / Ba in the shell portion may be 0.015 to 0.02.

[0010] The rare earth element in the shell portion may include dysprosium (Dy), and an atomic ratio of Dy / Ba in the shell portion may be 0.015 to 0.02.

[0011] The atomic ratio of R / Ti in the shell portion may be 0.012 to 0.02.

[0012] The rare earth element in the shell portion may include dysprosium (Dy), and an atomic ratio of Dy / Ti in the shell portion may be 0.012 to 0.02.

[0013] The core portion may include the barium titanate-based main component and a rare earth element (R), wherein the barium titanate-based main component includes barium (Ba) and titanium (Ti), and the rare earth element (R) includes at least one selected from the group consisting of dysprosium (Dy), terbium (Tb), yttrium (Y) and lanthanum (La).

[0014] The atomic ratio of R / Ba in the core portion may be 0.005 to 0.01.

[0015] The rare earth element in the core portion may include dysprosium (Dy), and an atomic ratio of Dy / Ba in the core portion may be 0.005 to 0.01.

[0016] The atomic ratio of R / Ti in the core portion may be 0.004 to 0.01.

[0017] The rare earth element in the core portion may include dysprosium (Dy), and an atomic ratio of Dy / Ti in the core portion may be 0.004 to 0.01.

[0018] According to some embodiments, a method for manufacturing a multilayer ceramic capacitor includes: preparing a dielectric powder in which a surface of a barium titanate-based main component is coated with a rare earth element (R), and the rare earth element (R) includes at least one selected from the group consisting of dysprosium (Dy), terbium (Tb), yttrium (Y) and lanthanum (La); manufacturing a dielectric green sheet using a dielectric slurry including the dielectric powder, 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; manufacturing a capacitor body including a dielectric layer and an inner electrode by firing the dielectric green sheet stack; and forming an outer electrode on the surface of the capacitor body. The dielectric layer includes a plurality of dielectric grains, at least one of the plurality of dielectric grains includes a core portion and a shell portion surrounding at least a portion of the core portion, the shell portion includes a barium titanate-based main component and a rare earth element (R), the barium titanate-based main component includes barium (Ba) and titanium (Ti), the rare earth element (R) includes at least one selected from the group consisting of dysprosium (Dy), terbium (Tb), yttrium (Y) and lanthanum (La), and a coefficient of variation (CV) of an atomic ratio of R / Ba and a coefficient of variation (CV) of an atomic ratio of R / Ti in the shell portion are both greater than 0 and less than 0.19.

[0019] The step of preparing the dielectric powder may include mixing the barium titanate-based main component and a rare earth element complex.

[0020] The rare earth element complex may include at least one selected from the group consisting of a dysprosium (Dy) complex, a terbium (Tb) complex, a yttrium (Y) complex, and a lanthanum (La) complex.

[0021] The rare earth element complex may be mixed in an amount of 0.1 parts by mol to 5 parts by mol based on 100 parts by mol of the barium titanate-based main component.

[0022] A multilayer ceramic capacitor according to some embodiments may improve reliability and dispersion characteristics by having a dielectric in which an additive component is uniformly distributed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0024] Figure 2 is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor cut along line I-I'.

[0025] Figure 3 is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor cut along line II-II'.

[0026] Figure 4is a schematic diagram showing the structure of a dielectric grain according to an embodiment.

[0027] Figure 5 is a low-magnification TEM image of the dielectric layer according to Example 1.

[0028] Figure 6 is a high-magnification TEM image of the dielectric layer according to Example 1.

[0029] Figure 7 is a low-magnification TEM image of the dielectric layer according to Comparative Example 1.

[0030] Figure 8 is a high-magnification TEM image of the dielectric layer according to Comparative Example 1.

[0031] Fig. 9 is a graph showing high temperature stress reliability of the multilayer ceramic capacitor according to Example 1.

[0032] Fig.10 is a graph showing high temperature stress reliability of the multilayer ceramic capacitor according to Comparative Example 1. DETAILED DESCRIPTION

[0033] The present disclosure will be described more fully below with reference to the accompanying drawings, in which embodiments of the present disclosure are shown. In order to clearly describe the present disclosure, parts or portions that are not related to the description are omitted, and throughout the specification, the same or similar constituent elements are represented by the same reference numerals. In addition, in the accompanying drawings, some constituent elements are enlarged, omitted or schematically shown, and the size of each constituent element does not fully reflect the actual size.

[0034] The accompanying drawings are provided only to make the embodiments disclosed in this specification easily understood and should not be interpreted as limiting the spirit of the present disclosure. It should be understood that the present disclosure includes all modifications, equivalents, and alternatives without departing from the scope and spirit of the present disclosure.

[0035] Terms including ordinal numbers such as first, second, etc. may be used to describe various constituent elements, but the constituent elements are not limited by the terms. These terms are used only for the purpose of distinguishing one constituent element from another constituent element.

[0036] It should be understood that when an element such as a layer, film, region, area, or substrate is referred to as being "on" or "over" another element, it may be directly on the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements. In addition, in the specification, the words "on..." or "over..." mean being disposed on or over a target portion, and do not necessarily mean being disposed on the upper side of the target portion based on the direction of gravity.

[0037] In the present application, terms such as "include" or "have" are intended to indicate the presence of the features, quantities, steps, operations, constituent elements, components, or combinations thereof described in the specification, and should be understood as not excluding the possibility of the presence or addition of one or more other features, quantities, steps, operations, constituent elements, components, or combinations thereof. In addition, unless explicitly described to the contrary, the words "include" or "have" will be understood to imply the inclusion of the stated elements without excluding any other elements.

[0038] Furthermore, throughout the specification, the phrase “on a plane” means observing a target portion from the top, and the phrase “on a cross section” means observing a cross section formed by vertically cutting the target portion from the side.

[0039] Throughout the specification, when a part is described as being “connected” to another part, the part may be “directly connected” to the other part, may be “connected” to the other part through a third part, or may be physically and / or electrically connected to the other part, and the part and the other part may be represented by different names according to position or function while being integrated.

[0040] In the following, reference will be made to Figures 1 to 3 A multilayer ceramic capacitor according to an embodiment is described.

[0041] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to this embodiment, Figure 2 is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor cut along line I-I', and Figure 3 is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor cut along line II-II'.

[0042] Figures 1 to 3The L-axis direction, W-axis direction, and T-axis direction shown in represent 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 constituent element. For example, the thickness direction (T-axis direction) may have the same concept as the stacking direction of the stacked dielectric layer 111. The length direction (L-axis direction) may be a direction extending parallel to the wide surface (main surface) of the sheet-like constituent element, and may be a direction substantially perpendicular to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be a direction along which the first external electrode 131 and the second external electrode 132 are relative to each other. The width direction (W-axis direction) is a direction extending parallel to the wide surface (main surface) of the sheet-like constituent element, and may be a direction substantially perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length of the sheet-like constituent element in the length direction (L-axis direction) may be greater than the length of the sheet-like constituent element in the width direction (W-axis direction).

[0043] Reference Figures 1 to 3 , the multilayer ceramic capacitor 100 according to the embodiment includes a capacitor body 110 and an external electrode disposed outside the capacitor body 110. The external electrode may include a first external electrode 131 and a second external electrode 132 disposed at both ends of the capacitor body 110 opposite to each other in the length direction (L-axis direction).

[0044] For example, the capacitor body 110 may have a substantially hexahedral shape.

[0045] For the convenience of describing the embodiment, two surfaces of the capacitor body 110 that are opposite to each other in the thickness direction (T-axis direction) are defined as a first surface and a second surface, two surfaces connected to the first surface and the second surface and opposite to each other in the length direction (L-axis direction) are defined as a third surface and a fourth surface, and two surfaces connected to the first surface and the second surface and the third surface and the fourth surface and opposite to each other in the width direction (W-axis direction) are defined as a fifth surface and a sixth surface.

[0046] For example, the first surface (lower surface) may be a mounting surface. In addition, the first to sixth surfaces may be flat, but the present disclosure is not limited thereto. For example, each of the first to sixth surfaces may be a curved surface having a convex central portion, and the corners as the boundaries of the surfaces may be rounded.

[0047] 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 present disclosure.

[0048] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrodes 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and first and second internal electrodes 121 and 122 alternately disposed in a thickness direction (T-axis direction) with the dielectric layers 111 interposed therebetween.

[0049] In this case, the dielectric layers 111 of the capacitor body 110 adjacent to each other may be integrated to such an extent that it is difficult to recognize a boundary therebetween without using a scanning electron microscope (SEM).

[0050] The capacitor body 110 may include an active region. The active region is a region where the dielectric layer 111 and the internal electrodes 121 and 122 are alternately disposed, and is a portion that contributes to forming the capacitance of the multilayer ceramic capacitor 100. Specifically, the active region may be a region where the first internal electrode 121 and the second internal electrode 122 stacked in the thickness direction (T-axis direction) overlap each other.

[0051] In addition, the capacitor body 110 may further include a cover portion and a side edge portion.

[0052] The covering portion may be an edge portion in the thickness direction and may be disposed on the upper and lower surfaces of the active region in the thickness direction (T-axis direction), respectively. The covering portion may be a single dielectric layer or two or more dielectric layers stacked on the upper and lower surfaces of the active region, respectively. The dielectric layer in the covering portion may be formed using the same material as the dielectric layer 111.

[0053] The side edge portions may be referred to as side covering portions (i.e., edge portions in the width direction), and may be respectively provided on both sides of the effective region that are opposite to each other in the width direction (W-axis direction) (i.e., surfaces of the effective region corresponding to the fifth surface and the sixth surface). The side edge portions may be formed by applying the conductive paste only on some areas of the surface of the dielectric green sheet and not on portions of the surface of the dielectric green sheet adjacent to both sides in the width direction when applying the conductive paste on the surface of the dielectric green sheet, stacking the dielectric green sheets, and then firing the stacked dielectric green sheets, but the present disclosure is not limited to this formation method.

[0054] The covering portion and the side margin portion serve to prevent the first and second internal electrodes 121 and 122 from being damaged due to physical stress or chemical stress.

[0055] The dielectric layer 111 includes dielectric grains. Figure 4 Describe the structure of dielectric grains.

[0056] Figure 4 is a schematic diagram showing the structure of a dielectric grain according to an embodiment.

[0057] Reference Figure 4 According to some embodiments, the dielectric grain 10 has a core-shell structure including a core portion 11 and a shell portion 12 surrounding at least a portion of the core portion 11 .

[0058] The shell 12 may include a barium titanate-based main component including barium (Ba) and titanium (Ti) and a rare earth element. The rare earth element may include at least one selected from the group consisting of dysprosium (Dy), terbium (Tb), yttrium (Y), and lanthanum (La).

[0059] In the shell 12, the rare earth element may be uniformly distributed on the surface of the core 11. According to some embodiments, the rare earth element may be uniformly distributed on the surface of the core 11 (dielectric material) by ionizing an additive component such as a rare earth element. Specifically, a dielectric powder coated with an additive component chemically adsorbed on the surface of a barium titanate-based main component may be used to obtain a multilayer ceramic capacitor in which the rare earth element is uniformly distributed in the dielectric layer 111.

[0060] The barium titanate-based main component is a dielectric matrix material, has a high dielectric constant, and contributes to the capacitance of the multilayer ceramic capacitor 100 .

[0061] For example, the barium titanate-based main component may include BaTiO 3 、Ba(Ti,Zr)O 3 、Ba(Ti,Sn)O 3 、(Ba,Ca)TiO 3 、(Ba,Ca)(Ti,Ca)O 3 、(Ba,Ca)(Ti,Zr)O 3 、(Ba,Ca)(Ti,Sn)O 3 、(Ba,Sr)TiO 3 、(Ba,Sr)(Ti,Zr)O 3 、(Ba,Sr)(Ti,Sn)O 3 or a combination thereof.

[0062] According to some embodiments, reliability and dispersion characteristics of a multilayer ceramic capacitor may be improved by uniformly distributing additive components such as rare earth elements on the surface of core 11 (ie, uniformly distributing additive components such as rare earth elements inside dielectric layer 111 ).

[0063] Specifically, when the rare earth element is R, the coefficient of variation (CV) of the atomic ratio of R / Ba in the shell portion 12 may be greater than 0 and less than 0.19, preferably 0.01 to 0.17. In addition, the coefficient of variation (CV) of the atomic ratio of R / Ti in the shell portion 12 may be greater than 0 and less than 0.19, preferably 0.01 to 0.17. Specifically, each of the coefficient of variation of the atomic ratio of R / Ba and the coefficient of variation of the atomic ratio of R / Ti within the range may indicate that the rare earth element (such as dysprosium (Dy) or the like) is uniformly distributed on the surface of the core portion 11. Therefore, a thin-layer multilayer ceramic capacitor having excellent reliability and dispersion characteristics can be ensured.

[0064] Each of the coefficient of variation (CV) of the atomic ratio of R / Ba and the coefficient of variation (CV) of the atomic ratio of R / Ti can be obtained by Formula 1 below.

[0065] [Formula 1]

[0066] Coefficient of variation of atomic ratio (CV) = [sample standard deviation of atomic ratio (σ) / average value of atomic ratio]

[0067] In Formula 1, the sample standard deviation (σ) of the atomic ratio refers to a value obtained by squaring and summing the deviations of the atomic ratios, dividing the sum by n-1 (n is the number of measurements) and taking the square root (ie, as shown in Formula 2 below).

[0068] [Formula 2]

[0069]

[0070] According to some embodiments, the rare earth element (R) included in the shell 12 may be dysprosium (Dy). In this case, the coefficient of variation (CV) of the atomic ratio of Dy / Ba obtained by Formula 1 in the shell 12 may be greater than 0 and less than 0.19, preferably 0.01 to 0.17. In addition, the coefficient of variation (CV) of the atomic ratio of Dy / Ti obtained by Formula 1 in the shell 12 may be greater than 0 and less than 0.19, preferably 0.01 to 0.17.

[0071] In the shell portion 12, the atomic ratio of R / Ba may be 0.015 to 0.02, preferably 0.016 to 0.019. If the atomic ratio of R / Ba in the shell portion 12 is within this range, the high temperature stress reliability of the multilayer ceramic capacitor may be improved.

[0072] According to some embodiments, the rare earth element (R) included in the shell portion 12 may be dysprosium (Dy). In this case, the atomic ratio of Dy / Ba in the shell portion 12 may be 0.015 to 0.02, preferably 0.016 to 0.019.

[0073] In the shell portion 12, the atomic ratio of R / Ti may be 0.012 to 0.02, preferably 0.012 to 0.017. If the atomic ratio of R / Ti in the shell portion 12 is within this range, the high temperature stress reliability of the multilayer ceramic capacitor may be improved.

[0074] According to some embodiments, the rare earth element (R) included in the shell portion 12 may be dysprosium (Dy). In this case, the atomic ratio of Dy / Ti in the shell portion 12 may be 0.012 to 0.02, preferably 0.012 to 0.017.

[0075] In the shell portion 12 , the atomic ratio of R / Ba, the atomic ratio of R / Ti, and the coefficient of variation (CV) of the atomic ratios can be obtained by transmission electron microscopy (TEM)-energy dispersive spectroscopy (EDS) analysis.

[0076] The cross-sectional sample can be obtained in the following manner: after the multilayer ceramic capacitor 100 is placed in the epoxy resin mixed solution and the placed multilayer ceramic capacitor 100 is cured, the surface (WT surface) in the W-axis direction and the T-axis direction of the capacitor body 110 is polished to a 1 / 2 depth position along the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber to observe the effective area (wherein the dielectric layer 111 and the internal electrodes 121 and 122 are alternately arranged). Next, a transmission electron microscope (TEM) can be used to measure the effective area of ​​the cross-sectional sample. TEM uses a Xe focused ion beam (FIB) to measure the effective area of ​​the cross-sectional sample in an area of ​​about 1.3 μm×1.3 μm of the visible dielectric layer 111 under an acceleration voltage condition of 200 kV. Next, in the TEM image of the measured cross-sectional sample, an EDS analysis can be performed on a point in each shell portion of at least one dielectric grain in a dielectric layer (for example, a point in each shell portion of 1 to 20 dielectric grains, 2 to 10 dielectric grains, or 3 to 7 dielectric grains). The atomic ratio of R / Ba may be the arithmetic mean of the atomic ratio of R / Ba at points in each shell portion of at least one dielectric grain, and the atomic ratio of R / Ti may be the arithmetic mean of the atomic ratio of R / Ti at points in each shell portion of at least one dielectric grain.

[0077] The core part 11 may include a barium titanate-based main component including barium (Ba) and titanium (Ti) and a rare earth element. The rare earth element may include at least one selected from the group consisting of dysprosium (Dy), terbium (Tb), yttrium (Y), and lanthanum (La).

[0078] The barium titanate-based main component is a dielectric matrix material, has a high dielectric constant, and contributes to the capacitance of the multilayer ceramic capacitor 100 .

[0079] For example, the barium titanate-based main component may include BaTiO 3、Ba(Ti, , Zr)O 3 、Ba(Ti,Sn)O 3 、(Ba,Ca)TiO 3 、(Ba,Ca)(Ti,Ca)O 3 、(Ba,Ca)(Ti,Zr)O 3 、(Ba,Ca)(Ti,Sn)O 3 、(Ba,Sr)TiO 3 、(Ba,Sr)(Ti,Zr)O 3 and (Ba,Sr)(Ti,Sn)O 3 At least one selected from the group consisting of.

[0080] Internal diffusion of the rare earth element coated on the surface of the barium titanate-based main component may be performed when the dielectric powder is manufactured, so that the rare earth element may be included in the core portion 11 .

[0081] According to some embodiments, since the core portion 11 includes a rare earth element such as dysprosium (Dy), etc., reliability of a thin-layer multilayer ceramic capacitor may be improved.

[0082] Specifically, when the rare earth element is R, the atomic ratio of R / Ba in the core portion 11 may be 0.005 to 0.01, preferably 0.006 to 0.009. If the atomic ratio of R / Ba in the core portion 11 is within this range, the high temperature stress reliability of the multilayer ceramic capacitor may be improved.

[0083] According to some embodiments, the rare earth element (R) included in the core portion 11 may be dysprosium (Dy). In this case, the atomic ratio of Dy / Ba in the core portion 11 may be 0.005 to 0.01, preferably 0.006 to 0.009.

[0084] The atomic ratio of R / Ti in the core portion 11 may be 0.004 to 0.01, preferably 0.004 to 0.008. If the atomic ratio of R / Ti in the core portion 11 is within this range, high temperature stress reliability of the multilayer ceramic capacitor may be improved.

[0085] According to some embodiments, the rare earth element (R) included in the core portion 11 may be dysprosium (Dy). In this case, the atomic ratio of Dy / Ti in the core portion 11 may be 0.004 to 0.01, preferably 0.004 to 0.008.

[0086] In the core portion 11 , the atomic ratio of R / Ba, the atomic ratio of R / Ti, and the coefficient of variation (CV) of the atomic ratios can be obtained by transmission electron microscopy (TEM)-energy dispersive spectroscopy (EDS) analysis.

[0087] Specifically, in a transmission electron microscope (TEM) image of a cross-sectional sample measured in the same manner as described above, EDS analysis may be performed on points in each core portion of at least one dielectric grain in one dielectric layer (e.g., points in each core portion of 1 to 20 dielectric grains, 2 to 10 dielectric grains, or 3 to 7 dielectric grains). The atomic ratio of R / Ba may be the arithmetic mean of the atomic ratios of R / Ba at the points in each core portion of at least one dielectric grain, and the atomic ratio of R / Ti may be the arithmetic mean of the atomic ratios of R / Ti at the points in each core portion of at least one dielectric grain.

[0088] The average thickness (average length in the T-axis direction) of the dielectric layer 111 may be 2.0 μm to 8.0 μm, preferably 2.4 μm to 7.8 μm. If the average thickness of the dielectric layer 111 is within the above range, the multilayer ceramic capacitor has excellent reliability.

[0089] The average thickness of the dielectric layer 111 can be obtained by placing the multilayer ceramic capacitor 100 in an epoxy resin mixed solution, curing the placed multilayer ceramic capacitor 100, polishing the cured multilayer ceramic capacitor 100, ion milling the polished multilayer ceramic capacitor 100, and then obtaining an image of the dielectric layer 111 using a scanning electron microscope (SEM). For example, the SEM can be a Verios G4 product from Thermo Fisher Scientific Inc., the measurement conditions can be 10 kV and 0.2 nA, the analysis magnification can be 100 times, and 1 or more layers (for example, 3 or more layers, 5 or more layers, or 10 or more layers) of the dielectric layer 111 can be measured. In the scanning electron microscope (SEM) image, the center point of the dielectric layer 111 in the length direction (L axis direction) or the width direction (W axis direction) can be used as a reference point. The average thickness of the dielectric layer 111 can be the arithmetic mean of the thickness of the dielectric layer 111 at ten points spaced apart from the reference point. The intervals of the ten points may be adjusted according to the scale of a scanning electron microscope (SEM) image. For example, the intervals of the ten points may be 1 μm to 100 μm, preferably 1 μm to 50 μm, and more preferably 1 μm to 10 μm. In this case, all ten points must be disposed within the dielectric layer 111. If not all ten points are disposed within the dielectric layer 111, the position of the reference point may be changed, or the intervals between the ten points may be adjusted.

[0090] The first inner electrode 121 and the second inner electrode 122 may be electrodes having different polarities, the first inner electrode 121 and the second inner electrode 122 may be alternately arranged opposite to each other along the T-axis direction with the dielectric layer 111 interposed between the first inner electrode 121 and the second inner electrode 122, and one end of the first inner electrode 121 and one end of the second inner electrode 122 may be exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0091] The first and second internal electrodes 121 and 122 may be electrically insulated from each other by a dielectric layer 111 disposed therebetween.

[0092] Ends of the first and second internal electrodes 121 and 122 alternately exposed through the third and fourth surfaces of the capacitor body 110 may be electrically connected to the first and second external electrodes 131 and 132 , respectively.

[0093] Each of the first and second internal electrodes 121 and 122 may include a conductive metal, for example, a metal such as Ni, Cu, Ag, Pd, Au, etc., or an alloy thereof (eg, Ag—Pd alloy).

[0094] In addition, each of the first and second internal electrodes 121 and 122 may include dielectric grains of the same composition as that of the ceramic material included in the dielectric layer 111 .

[0095] Each of the first and second internal electrodes 121 and 122 may be formed using a conductive paste including a conductive metal. A printing method of the conductive paste may be a screen printing method or a gravure printing method.

[0096] The average thickness of each of the first and second internal electrodes 121 and 122 may be 0.1 μm to 2 μm. The average thickness of each of the first and second internal electrodes 121 and 122 may be measured by scanning electron microscope (SEM) analysis. Here, since the scanning electron microscope (SEM) analysis is the same as the above-mentioned method of measuring the average thickness of the dielectric layer 111, the description thereof is omitted.

[0097] The capacitor body 110 may be formed by firing a laminated body in which a plurality of dielectric layers 111 and internal electrodes 121 and 122 are stacked.

[0098] The first and second external electrodes 131 and 132 may be supplied with voltages having different polarities and may be electrically connected to exposed portions of the first and second internal electrodes 121 and 122 , respectively.

[0099] If a predetermined voltage is applied to the first and second external electrodes 131 and 132, charges are accumulated between the first and second internal electrodes 121 and 122 facing each other. In this case, the capacitance of the multilayer ceramic capacitor 100 is proportional to the overlapping area of ​​the first and second internal electrodes 121 and 122 overlapping each other in the T-axis direction in the active region.

[0100] The first outer electrode 131 may include a first connecting portion and a first band portion, and the second outer electrode 132 may include a second connecting portion and a second band portion, the first connecting portion and the second connecting portion are respectively arranged on the third surface and the fourth surface of the capacitor body 110 to be connected to the first inner electrode 121 and the second inner electrode 122, respectively, and the first band portion and the second band portion are respectively arranged at the corners where the third surface and the fourth surface of the capacitor body 110 intersect with the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110.

[0101] The first and second band portions may extend from the first and second connecting portions, respectively, to a portion of the first and second surfaces and / or a portion of the fifth and sixth surfaces of the capacitor body 110. The first and second band portions may be used to increase the bonding strength between the first and second external electrodes 131 and 132 and the capacitor body 110.

[0102] Each of the first and second external electrodes 131 and 132 may include a sintered metal layer contacting the capacitor body 110 , a conductive resin layer disposed to cover the sintered metal layer, and a plated layer disposed to cover the conductive resin layer.

[0103] The sintered metal layer may include conductive metal and glass.

[0104] The conductive metal may include at least one selected from the group consisting of copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb) and alloys thereof. For example, the conductive metal including copper (Cu) may mean that the conductive metal includes single copper (Cu) or a copper (Cu) alloy. If the conductive metal includes copper, then 5 mol parts or less of a metal other than copper may be included relative to 100 mol parts of copper.

[0105] The glass may include a mixed oxide composition, for example, the composition may be one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide and alkaline earth metal oxide. The transition metal may include at least one 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 include at least one selected from the group consisting of lithium (Li), sodium (Na) and potassium (K), and the alkaline earth metal may include one or more selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba).

[0106] Alternatively, the conductive resin layer may be formed on the sintered metal layer, for example, the conductive resin layer may be formed to completely cover the sintered metal layer. On the other hand, the first and second external electrodes 131 and 132 may not include the sintered metal layer, in which case the conductive resin layer may directly contact the capacitor body 110.

[0107] The conductive resin layer may extend to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110, and the length of the region where the conductive resin layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 (i.e., the portion of the conductive resin layer corresponding to the band portion) may be greater than the length of the region where the sintered metal layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 (i.e., the portion of the sintered metal layer corresponding to the band portion). In other words, the conductive resin layer may be formed on the sintered metal layer, and may be formed to completely cover the sintered metal layer.

[0108] The conductive resin layer includes resin and conductive metal.

[0109] The resin included in the conductive resin layer is not particularly limited as long as it has bonding and impact absorption properties and is mixed with the conductive metal powder to form a paste, and may include, for example, phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0110] The conductive metal included in the conductive resin layer serves to be electrically connected to the first and second internal electrodes 121 and 122 or the sintered metal layer.

[0111] The conductive metal included in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof. In other words, the conductive metal may be made into only a flake shape, may be made into only a spherical shape, or may have a mixed shape of a flake shape and a spherical shape.

[0112] Here, the spherical shape may include a shape that is not a perfect sphere, for example, a shape in which the length ratio of the major axis to the minor axis (major axis length / minor axis length) is 1.45 or less. The flake shape refers to a flat and elongated shape, and the flake shape is not particularly limited, for example, the flake shape may include a shape in which the length ratio of the major axis to the minor axis (major axis length / minor axis length) is 1.95 or more.

[0113] Each of the first and second external electrodes 131 and 132 may further include a plating layer disposed outside the conductive resin layer.

[0114] The plating layer may include at least one selected from the group consisting of nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb) and alloys thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, and may have a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are stacked in sequence, or may have a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer and a tin (Sn) plating layer are stacked in sequence. In addition, the plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0115] The plating layer may improve the mountability with a substrate, structural reliability, durability to the outside, thermal resistance, or equivalent series resistance (ESR) of the multilayer ceramic capacitor 100 .

[0116] Hereinafter, a method of manufacturing the multilayer ceramic capacitor 100 according to an embodiment will be described.

[0117] According to some embodiments, the multilayer ceramic capacitor 100 can be manufactured by the following steps: a step of preparing a dielectric powder in which the surface of a barium titanate-based main component is coated with a rare earth element (R) (including dysprosium (Dy), terbium (Tb), yttrium (Y), lanthanum (La) or a combination thereof); a step of manufacturing a dielectric green sheet using a dielectric slurry including the dielectric powder and forming a conductive paste layer on the surface of the dielectric green sheet; a step of manufacturing a dielectric green sheet stack by stacking the dielectric green sheets having the conductive paste layer formed thereon; a step of manufacturing a capacitor body including a dielectric layer and an inner electrode by firing the dielectric green sheet stack; and a step of forming an outer electrode on the surface of the capacitor body.

[0118] The dielectric powder corresponding to the dielectric grains, ie, the dielectric powder in which the surface of the barium titanate-based main component is coated with a rare earth element such as dysprosium (Dy), can be prepared by mixing the barium titanate-based main component and the rare earth element complex.

[0119] To achieve high-performance multilayer ceramic capacitors, it is necessary to make the dielectric layer thinner and to make the high-level additive microstructure uniform. The size of the additive component in the form of oxide varies from tens of nm to several μm, and attempts are being made to crush the oxide additive into smaller pieces by performing strong grinding to uniformly disperse the additive component in the form of oxide. However, there are obstacles such as the introduction of impurities during the crushing process, changes in the composition ratio of the additive component and the dielectric material due to incomplete crushing, which limits the physical crushing process.

[0120] According to some embodiments, unlike a method of physically mixing a barium titanate-based main component and an additive component in oxide form, chemical adsorption between an ionized additive component and the barium titanate-based main component may be induced to induce a more uniform distribution of the additive component.

[0121] The barium titanate-based main component can be prepared by various methods such as a solid phase synthesis method, a hydrothermal synthesis method, a sol-gel method, and the like.

[0122] The rare earth element complex may include at least one selected from the group consisting of a dysprosium (Dy) complex, a terbium (Tb) complex, a yttrium (Y) complex, and a lanthanum (La) complex.

[0123] The rare earth element complex may be a compound having an ion form in which the rare earth element is dispersed in an organic compound such as a carbonyl compound or the like.

[0124] The use of ionizing additive components (eg, rare earth element complexes) can induce a uniform coating on the surface of the barium titanate-based main component. Thus, it is possible to ensure that the rare earth element is uniformly distributed on the surface of the barium titanate-based main component in the dielectric layer.

[0125] The rare earth element complex may be mixed in an amount of 0.1 to 5 mol parts (preferably 0.5 to 4 mol parts) based on 100 mol parts of the barium titanate-based main component. If the rare earth element complex is mixed within this content range, the rare earth element may be uniformly coated on the surface of the barium titanate-based main component.

[0126] In addition to the obtained dielectric powder, a dielectric slurry may be prepared by further mixing additives such as a dispersant, a binder, a plasticizer, a lubricant, an antistatic agent, etc., and a solvent.

[0127] For example, the dispersant may include a phosphate dispersant, a polycarboxylic acid dispersant, or a combination thereof. Based on 100 parts by weight of the barium titanate-based main component, the dispersant may be mixed in an amount of 0.1 to 5 parts by weight (preferably, 0.3 to 3 parts by weight). If the dispersant is mixed within this content range, the dispersibility of the dielectric slurry will be excellent, and the amount of impurities introduced into the manufactured dielectric layer can be reduced.

[0128] For example, the binder may include acrylic resin, polyvinyl butyral resin, polyvinyl acetal resin, ethyl cellulose resin, etc. Based on 100 parts by weight of the barium titanate-based main component, the binder may be added in an amount of 0.1 parts by weight to 50 parts by weight (preferably, 3 parts by weight to 30 parts by weight). If the binder is mixed within this content range, the dispersibility of the dielectric slurry will be excellent, and the amount of impurities introduced into the manufactured dielectric layer can be reduced.

[0129] For example, the plasticizer may include at least one selected from the group consisting of phthalic acid compounds (such as dioctyl phthalate, benzyl butyl phthalate, dibutyl phthalate, dihexyl phthalate, di(2-ethylbutyl)phthalate, etc.), adipic acid compounds (such as dihexyl adipate, di(2-ethylhexyl adipate, etc.), glycolic acid compounds (such as ethylene glycol, diethylene glycol, triethylene glycol, etc.), glycol ester compounds (such as triethylene glycol dibutyrate, triethylene glycol di(2-ethylbutyrate), triethylene glycol di(2-ethylhexanoate), etc.). The plasticizer may be added in an amount of 0.1 to 20 parts by weight (preferably, 1 to 10 parts by weight) based on 100 parts by weight of the barium titanate-based main component. If the plasticizer is mixed within this content range, the dispersibility of the dielectric slurry may be excellent, and the amount of impurities introduced into the manufactured dielectric layer may be reduced.

[0130] The solvent may be an aqueous solvent such as water, etc., an alcohol solvent such as ethanol, methanol, benzyl alcohol, methoxyethanol, etc., an glycolic acid solvent such as ethylene glycol, diethylene glycol, etc., a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc., an ester solvent such as butyl acetate, ethyl acetate, carbitol acetate, butyl carbitol acetate, etc., an ether solvent such as methyl cellosolve, ethyl cellosolve, butyl ether, tetrahydrofuran, etc., or an aromatic solvent such as benzene, toluene, xylene, etc. For example, in consideration of the solubility or dispersibility of various additives included in the dielectric slurry, the solvent may be an alcohol solvent or an aromatic solvent. Based on 100 parts by weight of the barium titanate-based main component, the solvent may be mixed in an amount of 50 parts by weight to 1000 parts by weight (preferably, 100 parts by weight to 500 parts by weight). If the solvent is mixed within this content range, the components of the dielectric slurry may be fully mixed, and then the solvent may be easily removed.

[0131] The mixing of the dielectric slurry including the dielectric powder in which the surface of the barium titanate-based main component is coated with the rare earth element can be performed using a wet ball mill or a stirred mill. If zirconia balls are used in the wet ball mill, a plurality of zirconia balls having a diameter of 0.1 mm to 10 mm can be used for wet mixing for 8 to 48 hours (preferably, 10 to 24 hours).

[0132] After firing, the prepared dielectric slurry is formed into a dielectric layer.

[0133] The method for forming the prepared dielectric slurry into a sheet may include a belt molding method such as a doctor blade method, a calendar roll method, etc. For example, the method for molding the prepared dielectric slurry may use a roll-on molding coater of a head discharge method, and a dielectric green sheet may be obtained by drying the molded body.

[0134] In order to form a conductive paste layer that becomes an internal electrode after firing, a conductive paste can be prepared by mixing a conductive powder made of a conductive metal or an alloy thereof, a binder, and a solvent. In addition, if necessary, barium titanate powder as a common material can be mixed together. The common material can be used to suppress the sintering of the conductive powder during the firing process. The conductive paste layer is formed by applying the conductive paste to the surface of the dielectric green sheet in a predetermined pattern using various printing methods (such as screen printing, etc.) or transfer methods.

[0135] The conductive powder may include nickel (Ni) or a nickel (Ni) alloy.

[0136] Next, the dielectric green sheets formed with the internal electrode patterns are stacked in multiple layers, and then the stacked dielectric green sheets are pressed in the stacking direction, thereby manufacturing a dielectric green sheet laminate. In this case, the dielectric green sheets and the internal electrode patterns may be stacked so that the dielectric green sheets are disposed on the upper and lower surfaces of the dielectric green sheet laminate in the stacking direction.

[0137] The step of cutting the manufactured dielectric green sheet laminate into a predetermined size by dicing or the like may be selectively performed.

[0138] Furthermore, if necessary, the dielectric green sheet stack may be cured and dried to remove the plasticizer, etc., and after the dielectric green sheet stack is cured and dried, the cured and dried dielectric green sheet stack may be subjected to drum polishing using a horizontal centrifugal drum machine, etc. In drum polishing, the dielectric green sheet stack may be placed in a drum container together with a medium and a polishing liquid, and a rotational motion or vibration may be applied to the drum container so that unnecessary portions (such as burrs, etc.) generated during cutting are polished. In addition, after drum polishing, the dielectric green sheet stack may be washed with a cleaning solution (such as water, etc.), and the washed dielectric green sheet stack may be dried.

[0139] Next, a capacitor body can be manufactured by removing the binder from the dielectric green sheet stack and firing the dielectric green sheet stack from which the binder has been removed.

[0140] The binder removal treatment conditions may be appropriately adjusted according to the composition of the dielectric layer or the composition of the inner electrode. For example, the temperature rise rate during the binder removal treatment may be 5° C. / hour to 300° C. / hour, the carrier temperature during the binder removal treatment may be 180° C. to 400° C., and the temperature holding time during the binder removal treatment may be 0.5 hour to 24 hours. The atmosphere during the binder removal treatment may be an air atmosphere or a reducing atmosphere.

[0141] The conditions of the firing process may be appropriately adjusted according to the main component of the dielectric layer or the main component of the inner electrode. For example, the firing may be performed at a temperature of 1100° C. to 1400° C. (preferably, 1200° C. to 1350° C.). In addition, the firing may be performed for 0.5 hours to 8 hours (preferably, 1 hour to 3 hours). In addition, the firing may be performed in a reducing atmosphere (for example, an atmosphere of a humidified mixed gas including nitrogen and hydrogen). If the inner electrode includes nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere may be 1.0×10 -14 MPa to 1.0×10 -10 MPa.

[0142] After the firing process, annealing may be performed if necessary. Annealing may be a process for reoxidizing the dielectric layer, and may be performed if the firing process is performed in a reducing atmosphere. The conditions of the annealing process may be appropriately adjusted according to the composition of the dielectric layer. For example, the temperature during the annealing may be 950° C. to 1150° C., the annealing time may be 0 hours to 20 hours, and the temperature increase rate during the annealing may be 50° C. / hour to 500° C. / hour. The annealing atmosphere may be humidified nitrogen (N 2 ) atmosphere, and the oxygen partial pressure in the annealing atmosphere may be 1.0×10 -9 MPa to 1.0×10 -5 MPa.

[0143] In the binder removal process, the firing process, or the annealing process, for example, a wetting agent or the like may be used to humidify nitrogen gas or a mixed gas or the like. In this case, the temperature of water may be 5° C. to 75° C. The binder removal process, the firing process, or the annealing process may be performed sequentially or may be performed independently.

[0144] Optionally, surface treatment (such as sandblasting, laser irradiation, drum polishing, etc.) may be performed on the third and fourth surfaces of the manufactured capacitor body 110. By performing the surface treatment, the end of the first inner electrode and the end of the second inner electrode may be exposed on the third and fourth surfaces as the outermost surfaces. Therefore, the electrical connection between the first outer electrode and the first inner electrode and the electrical connection between the second outer electrode and the second inner electrode may become good, and the alloy portion may be easily formed.

[0145] Next, external electrodes are formed on the surface of the manufactured capacitor body 110 .

[0146] For example, a paste for forming the sintered metal layer may be applied to the surface of the capacitor body 110 and then sintered to form the sintered metal layer.

[0147] The paste for forming the sintered metal layer may include conductive metal and glass. The description of the conductive metal and glass is the same as above, so the repeated description is omitted. In addition, the paste for forming the sintered metal layer may selectively include a binder, a solvent, a dispersant, a plasticizer, an oxide powder, etc. For example, the binder may include ethyl cellulose, acryl, butyral, etc., and the solvent may include an organic solvent (e.g., terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0148] The method of applying the paste for forming the sintered metal layer to the outer surface of the capacitor body 110 may include various methods, for example, a printing method (such as a screen printing method, etc.), a dipping method, a coating method using a dispenser, etc., a spraying method using a sprayer, etc. 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 may be selectively applied to a portion of at least one of the first, second, fifth, and sixth surfaces (a portion on which the band portion of each of the first and second external electrodes is formed).

[0149] Thereafter, the capacitor body 110 on which the paste for forming the sintered metal layer is applied is dried, and the dried capacitor body is sintered at a temperature of 700° C. to 1000° C. for 0.1 to 3 hours to form a sintered metal layer.

[0150] Alternatively, a paste for forming the conductive resin layer may be applied to the outer surface of the capacitor body 110 , and then the applied paste may be cured to form the conductive resin layer.

[0151] The paste for forming the conductive resin layer may include resin and conductive metal, and may optionally include non-conductive filler. The description of conductive metal and resin is the same as above, so its repeated description is omitted. In addition, the paste for forming the conductive resin layer may optionally include adhesive, solvent, dispersant, plasticizer, oxide powder, etc. For example, the adhesive may include ethyl cellulose, acryl, butyral, etc., and the solvent may be an organic solvent (for example, terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0152] According to some embodiments, the conductive resin layer may be formed by immersing the capacitor body 110 in a paste for forming the conductive resin layer and then curing the immersed capacitor body, the conductive resin layer may be formed by printing the paste for forming the conductive resin layer on the surface of the capacitor body 110 using screen printing, gravure printing, etc., or the conductive resin layer may be formed by applying the paste for forming the conductive resin layer to the surface of the capacitor body 110 and then curing the applied paste.

[0153] Next, a plating layer is formed on the outer side of the conductive resin layer.

[0154] For example, the plated layer may be formed by a plating method, or may be formed by sputtering or electrodeposition.

[0155] Hereinafter, the above embodiments will be described in more detail through the following examples. However, the following examples are only for illustrative purposes and do not limit the scope of the present disclosure.

[0156] (Manufacture of multilayer ceramic capacitors)

[0157] Example 1

[0158] The barium titanate powder and the dysprosium (Dy) carbonyl compound in the form of ions are mixed in an amount of 3 parts by mole based on 100 parts by mole of the barium titanate powder to prepare a dielectric powder having Dy coated on the surface of the barium titanate powder. That is, in the dielectric powder, the surface of the barium titanate-based main component is coated with a rare earth element such as dysprosium (Dy).

[0159] The prepared dielectric powders are mixed to prepare dielectric slurry. The mixing is performed in the following manner: zirconium oxide (ZrO 2 ) balls are used as a dispersion medium, ethanol or toluene, a wetting dispersant and polyvinyl butyral (PVB) resin as a binder are added, and then mechanical grinding is performed.

[0160] The prepared dielectric slurry was used to manufacture a dielectric green sheet by a roll-on coating machine of a die-discharging type.

[0161] A conductive paste layer including nickel (Ni) was printed on the surface of the dielectric green sheet, and a dielectric green sheet laminate (width×length×height=3.2 mm×2.5 mm×2.5 mm) was manufactured by stacking and pressing the dielectric green sheets having the conductive paste layer formed thereon.

[0162] The dielectric green sheet stack is plasticized at 400° C. or less in a nitrogen atmosphere, and fired at 1300° C. or less and 1.0% or less of hydrogen (H 2 ) concentration and firing the dielectric green sheet stack.

[0163] Subsequently, external electrodes are formed by a process such as plating to manufacture a multilayer ceramic capacitor.

[0164] Comparative Example 1

[0165] By mixing 3 mol parts of dysprosium oxide (Dy) based on 100 mol parts of barium titanate powder, 2 O 3 ) is mixed with barium titanate powder to prepare dielectric slurry. The mixing is carried out in the following manner: zirconium oxide (ZrO 2 ) balls are used as a dispersion medium, ethanol or toluene, a wetting dispersant and polyvinyl butyral (PVB) resin as a binder are added, and then mechanical grinding is performed.

[0166] A multilayer ceramic capacitor was manufactured in the same manner as in Example 1 using the prepared dielectric slurry.

[0167] Assessment 1: TEM-EDS analysis

[0168] The multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1 were subjected to transmission electron microscopy (TEM)-energy dispersive spectroscopy (EDS) analysis, and the results are shown in FIG. Figures 5 to 8 and in Tables 1 and 2.

[0169] TEM-EDS analysis was performed by the following method. A cross-sectional sample was obtained in the following manner: after the multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1 were placed in an epoxy resin mixed solution and the placed multilayer ceramic capacitors were cured, the surface of the capacitor body in the W-axis direction and the T-axis direction (WT surface) was polished to a 1 / 2 depth position in the L-axis direction, and the polished capacitor body was kept in a vacuum atmosphere chamber so that an effective area where the dielectric layer and the internal electrode were alternately arranged was observed. The effective area of ​​the cross-sectional sample was measured by TEM. TEM used a Xe focused ion beam (FIB) under an acceleration voltage of 200 kV to measure the effective area of ​​the cross-sectional sample in an area of ​​approximately 1.3 μm×1.3 μm where the dielectric layer 111 was visible, and the results are shown in FIG. Figure 5 and Figure 7 middle.

[0170] like Figure 6 and Figure 8 As shown, in the transmission electron microscope (TEM) image of the measured cross-sectional sample, EDS analysis can be performed on points in five core portions and five shell portions in one dielectric layer. The arithmetic mean of the atomic ratio of Dy / Ba and the arithmetic mean of the atomic ratio of Dy / Ti at the points in the five core portions and the arithmetic mean of the atomic ratio of Dy / Ba and the arithmetic mean of the atomic ratio of Dy / Ti at the points in the five shell portions are obtained by EDS analysis, and the results are shown in Tables 1 and 2 below.

[0171] Figure 5 is a low-magnification TEM image of the dielectric layer according to Example 1, Figure 6 is a high-magnification TEM image of the dielectric layer according to Example 1. Figure 7 is a low-magnification TEM image of the dielectric layer according to Comparative Example 1, Figure 8 is a high-magnification TEM image of the dielectric layer according to Comparative Example 1.

[0172] The following Table 1 is an EDS analysis result of the dielectric layer of the multilayer ceramic capacitor according to Example 1, and the following Table 2 is an EDS analysis result of the dielectric layer of the multilayer ceramic capacitor according to Comparative Example 1.

[0173] (Table 1)

[0174]

[0175] (Table 2)

[0176]

[0177]

[0178] Reference Figure 5 and Figure 7 It can be seen that in Example 1 (ie, Example 1 prepared by a coating method using ionized rare earth elements according to some embodiments), rare earth elements such as dysprosium (Dy) are uniformly distributed on the surface of barium titanate in the shell portion.

[0179] In addition, it can be seen from Tables 1 and 2 that in Example 1, the coefficient of variation of the atomic ratio of R / Ba in the shell and the coefficient of variation of the atomic ratio of R / Ti are both less than 0.19. On the other hand, it can be seen that in Comparative Example 1, the coefficient of variation of the atomic ratio of R / Ba in the shell and the coefficient of variation of the atomic ratio of R / Ti are both greater than or equal to 0.19. Thus, it can be seen that the dielectric layer of the multilayer ceramic capacitor according to the embodiment has rare earth elements uniformly distributed on the surface of barium titanate.

[0180] In addition, it can be seen that in Example 1 prepared by a coating method using an ionized rare earth element according to an embodiment, the rare earth element is internally diffused, so that more rare earth elements (such as dysprosium (Dy)) are observed in the core portion of Example 1 than in the core portion of Comparative Example 1. For example, the average value of the atomic ratio of the rare earth element (such as dysprosium (Dy)) observed in the core portion of Example 1 may be greater than the average value of the atomic ratio of the rare earth element (such as dysprosium (Dy)) observed in the core portion of Comparative Example 1.

[0181] Assessment 2: Reliability

[0182] The high temperature stress reliability (or high temperature harsh reliability) of the multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1 was measured by a highly accelerated life test (HALT), and the results are shown in FIG. Fig. 9 and Fig.10 middle.

[0183] Specifically, 76 multilayer ceramic capacitors manufactured in Example 1 and 76 multilayer ceramic capacitors manufactured in Comparative Example 1 were prepared and mounted on a measurement substrate, and high temperature stress reliability was measured using an ESPEC PV-222HALT device under the conditions of 105°C, 12 hours, and 9.45 V (or a voltage of 9.45 V).

[0184] Fig. 9 is a graph showing high temperature stress reliability of the multilayer ceramic capacitor according to Example 1, Fig.10 is a graph showing high temperature stress reliability of the multilayer ceramic capacitor according to Comparative Example 1.

[0185] Reference Fig. 9 and Fig.10 , it can be seen that, compared with Comparative Example 1, Example 1 according to the embodiment (the coefficient of variation of the atomic ratio of R / Ba and the coefficient of variation of the atomic ratio of R / Ti in the shell portion are both less than 0.19) has excellent high-temperature stress reliability.

[0186] While the present disclosure has been described in connection with what are presently considered to be practical embodiments, it should be understood that the present disclosure is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as An external electrode, disposed outside the capacitor body, Wherein, the dielectric layer includes a plurality of dielectric grains. At least one of the plurality of dielectric grains comprises a core portion and a shell portion surrounding at least a portion of the core portion, wherein the shell portion includes a barium titanate-based main component and a rare earth element, the barium titanate-based main component includes barium and titanium, the rare earth element includes at least one selected from the group consisting of dysprosium, terbium, yttrium and lanthanum, and wherein the coefficient of variation of the atomic ratio of R / Ba and the coefficient of variation of the atomic ratio of R / Ti in the shell are both greater than 0 and less than 0.19, Wherein, the coefficient of variation of atomic ratio = [sample standard deviation of atomic ratio / average value of atomic ratio], Wherein, R represents the rare earth element, Ba represents barium, and Ti represents titanium.

2. The multilayer ceramic capacitor according to claim 1, wherein The rare earth element in the shell portion includes dysprosium, and a coefficient of variation of an atomic ratio of Dy / Ba and a coefficient of variation of an atomic ratio of Dy / Ti in the shell portion are both greater than 0 and less than 0.19, wherein Dy represents dysprosium.

3. The multilayer ceramic capacitor according to claim 1, wherein The atomic ratio of R / Ba in the shell portion is 0.015 to 0.

02.

4. The multilayer ceramic capacitor according to claim 1, wherein The rare earth element in the shell portion includes dysprosium, and an atomic ratio of Dy / Ba in the shell portion is 0.015 to 0.02, wherein Dy represents dysprosium.

5. The multilayer ceramic capacitor according to claim 1, wherein The atomic ratio of R / Ti in the shell portion is 0.012 to 0.

02.

6. The multilayer ceramic capacitor according to claim 1, wherein The rare earth element in the shell portion includes dysprosium, and an atomic ratio of Dy / Ti in the shell portion is 0.012 to 0.02, wherein Dy represents dysprosium.

7. The multilayer ceramic capacitor according to claim 1, wherein: The core portion includes the barium titanate-based main component including barium and titanium and a rare earth element including at least one selected from the group consisting of dysprosium, terbium, yttrium, and lanthanum.

8. The multilayer ceramic capacitor according to claim 7, wherein: The atomic ratio of R / Ba in the core portion is 0.005 to 0.

01.

9. The multilayer ceramic capacitor according to claim 7, wherein: The rare earth element in the core portion includes dysprosium, and an atomic ratio of Dy / Ba in the core portion is 0.005 to 0.01, wherein Dy represents dysprosium.

10. The multilayer ceramic capacitor according to claim 7, wherein: The atomic ratio of R / Ti in the core portion is 0.004 to 0.

01.

11. The multilayer ceramic capacitor according to claim 7, wherein: The rare earth element in the core portion includes dysprosium, and an atomic ratio of Dy / Ti in the core portion is 0.004 to 0.01, wherein Dy represents dysprosium.

12. A method of manufacturing a multilayer ceramic capacitor, comprising: preparing a dielectric powder in which a surface of a barium titanate-based main component is coated with a rare earth element, the rare earth element comprising at least one selected from the group consisting of dysprosium, terbium, yttrium and lanthanum; manufacturing a dielectric green sheet using a dielectric slurry including the dielectric powder, 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 by firing the dielectric green sheet laminate; and forming external electrodes on a surface of the capacitor body, The dielectric layer includes a plurality of dielectric grains, at least one of the plurality of dielectric grains includes a core portion and a shell portion surrounding at least a portion of the core portion, wherein the shell portion includes a barium titanate-based main component and a rare earth element, the barium titanate-based main component includes barium and titanium, and the rare earth element includes at least one selected from the group consisting of dysprosium, terbium, yttrium and lanthanum, wherein the coefficient of variation of the atomic ratio of R / Ba and the coefficient of variation of the atomic ratio of R / Ti in the shell are both greater than 0 and less than 0.19, Here, the coefficient of variation of the atomic ratio = [sample standard deviation of the atomic ratio / average value of the atomic ratio].

13. The method according to claim 12, wherein: The step of preparing the dielectric powder includes mixing the barium titanate-based main component and a rare earth element complex.

14. The method according to claim 13, wherein: The rare earth element complex includes at least one selected from the group consisting of a dysprosium complex, a terbium complex, a yttrium complex, and a lanthanum complex.

15. The method according to claim 13, wherein: The rare earth element complex is mixed in an amount of 0.1 parts by mol to 5 parts by mol based on 100 parts by mol of the barium titanate-based main component.

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