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 includes: a capacitor body including a dielectric layer and an inner electrode layer; and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric crystal grains, at least one of the dielectric crystal 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 main component including barium (Ba) and titanium (Ti), and a sub-component including tin (Sn), the shell portion includes a Sn-concentrated region containing tin (Sn) and a Sn-non-concentrated region containing tin (Sn) with atom% less than atom% of tin (Sn) in the Sn-concentrated region, and an atomic ratio of tin (Sn) contained in the Sn-concentrated region to tin (Sn) contained in the Sn-non-concentrated region is 2.0 to 6.0.

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic capacitor and a method of manufacturing the same. 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, a multilayer ceramic capacitor (MLCC) can be mounted on a substrate of various electronic products (e.g., 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 capacitor (MLCC) is used as a chip capacitor to which it is charged or discharged.

[0004] In particular, as the demand for ultra-small and high-capacity MLCCs increases in the IT industry, high reliability is required under ultra-thin designs. Summary of the invention

[0005] The embodiment provides a multilayer ceramic capacitor having excellent reliability. In addition, even a small multilayer ceramic capacitor having a thin dielectric layer can have excellent reliability.

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

[0007] A multilayer ceramic capacitor according to an embodiment includes: a capacitor body including a dielectric layer and an inner electrode layer; 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 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 secondary component, the barium titanate-based main component includes barium (Ba) and titanium (Ti), the secondary component includes tin (Sn), the shell portion includes a Sn concentrated region including tin (Sn) and a Sn non-concentrated region including tin (Sn) having an atomic % less than the atomic % of tin (Sn) in the Sn concentrated region, and the atomic ratio of tin (Sn) contained in the Sn concentrated region to tin (Sn) contained in the Sn non-concentrated region is 2.0 to 6.0.

[0008] The shell portion may be a region having a depth of 15 nm to 25 nm from the outermost portion of the at least one dielectric grain to the inside of the at least one dielectric grain.

[0009] In a transmission electron microscope (TEM)-energy dispersive spectroscopy (EDS) line analysis of a straight line segment from one outermost point of the at least one dielectric grain through the center of the at least one dielectric grain to another outermost point of the at least one dielectric grain, the Sn concentrated region may have a peak with the highest atom % of tin (Sn).

[0010] The Sn non-concentration region may include tin (Sn) in an amount of 0.8 atom% or less based on the total amount of elements in the shell portion.

[0011] The length of the Sn concentration region may be 40% to 100% of the length of the major axis of the at least one dielectric grain.

[0012] The plurality of dielectric grains include 30 to 50 dielectric grains, and 30% to 100% of the 30 to 50 dielectric grains include the Sn concentrated region.

[0013] The at least one dielectric grain may have an average grain size of 80 nm to 160 nm.

[0014] The core portion may include the barium titanate-based main component including barium (Ba) and titanium (Ti).

[0015] Tin (Sn) may be included in an amount of 0.01 to 5 parts by mol based on 100 parts by mol of the barium titanate-based main component in the shell portion.

[0016] The subcomponent may further include dysprosium (Dy), terbium (Tb), manganese (Mn), vanadium (V), barium (Ba), silicon (Si), aluminum (Al), calcium (Ca), or a combination thereof.

[0017] In the shell portion, based on 100 mol parts of the barium titanate-based main component, dysprosium (Dy) in an amount of 0.01 mol part to 5 mol parts may be included, terbium (Tb) in an amount of 0.01 mol part to 5 mol parts may be included, manganese (Mn) in an amount of 0.01 mol part to 5 mol parts may be included, vanadium (V) in an amount of 0.01 mol part to 5 mol parts may be included, barium (Ba) in an amount of 0.01 mol part to 5 mol parts may be included, silicon (Si) in an amount of 0.01 mol part to 5 mol parts may be included, aluminum (Al) in an amount of 0.01 mol part to 5 mol parts may be included, calcium (Ca) in an amount of 0.01 mol part to 5 mol parts may be included, or a combination thereof.

[0018] The length of the Sn concentration region may be 43% to 75% of the length of the major axis of the at least one dielectric grain.

[0019] A method for manufacturing a multilayer ceramic capacitor according to an embodiment includes: preparing a dielectric slurry by mixing a barium titanate-based main component powder and a subcomponent powder including a tin (Sn) compound; manufacturing a dielectric green sheet from 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 a plurality of dielectric green sheets on which the conductive paste layer is formed; manufacturing a capacitor body including a dielectric layer and an inner electrode layer by firing the dielectric green sheet laminate; and forming an outer electrode on an outer surface of the capacitor body. The dielectric layer includes a plurality of dielectric grains, at least one of the 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 subcomponent, the barium titanate-based main component includes barium (Ba) and titanium (Ti), the subcomponent includes tin (Sn), the shell portion includes a Sn concentrated region containing tin (Sn) and a Sn non-concentrated region containing tin (Sn) at an atom % less than the atom % of tin (Sn) in the Sn concentrated region, and an atomic ratio of tin (Sn) contained in the Sn concentrated region to tin (Sn) contained in the Sn non-concentrated region is 2.0 to 6.0.

[0020] The tin (Sn)-containing compound is mixed in an amount of 0.01 parts by mole to 5 parts by mole based on 100 parts by mole of the barium titanate-based main component powder.

[0021] The auxiliary component powder may further include a dysprosium (Dy)-containing compound, a terbium (Tb)-containing compound, a manganese (Mn)-containing compound, a vanadium (V)-containing compound, a barium (Ba)-containing compound, a silicon (Si)-containing compound, an aluminum (Al)-containing compound, a calcium (Ca)-containing compound, or a combination thereof.

[0022] Based on 100 mol parts of barium titanate-based main component powder, it may include a dysprosium (Dy) compound in an amount of 0.01 mol part to 5 mol parts, a terbium (Tb) compound in an amount of 0.01 mol part to 5 mol parts, a manganese (Mn) compound in an amount of 0.01 mol part to 5 mol parts, a vanadium (V) compound in an amount of 0.01 mol part to 5 mol parts, a barium (Ba) compound in an amount of 0.01 mol part to 5 mol parts, a silicon (Si) compound in an amount of 0.01 mol part to 5 mol parts, an aluminum (Al) compound in an amount of 0.01 mol part to 5 mol parts, a calcium (Ca) compound in an amount of 0.01 mol part to 5 mol parts, or a combination thereof.

[0023] The dielectric green sheet stack may be fired at a firing temperature greater than 1160°C and equal to or less than 1220°C.

[0024] It can be used in the presence of less than or equal to 1.0% hydrogen (H 2) concentration in an atmosphere wherein the dielectric green sheet stack is fired.

[0025] The dielectric slurry may further be mixed with a dispersant, wherein the dispersant may be mixed in an amount of 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the barium titanate-based main component powder.

[0026] The multilayer ceramic capacitor according to the embodiment can improve reliability by suppressing grain growth of dielectric grains and improving resistance of grain boundaries, which is beneficial for improving reliability of a small multilayer ceramic capacitor with a thin dielectric layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0028] Figure 2 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor taken along line II' in FIG.

[0029] Figure 3 It is along Figure 1 A cross-sectional view of the multilayer ceramic capacitor taken along line II-II'.

[0030] Figure 4 is a schematic diagram illustrating the structure of one dielectric grain within a dielectric layer according to an embodiment.

[0031] Figure 5 is a TEM image of the dielectric layer according to Example 1.

[0032] Fig. 6A is a TEM image showing dielectric grains within the dielectric layer according to Example 1.

[0033] Figure 6B yes Fig. 6A EDS line analysis diagram of dielectric grains.

[0034] Figure 7 is a SEM image of the dielectric layer according to Example 1.

[0035] Figure 8 is a SEM image of the dielectric layer according to Comparative Example 1.

[0036] Fig. 9 is a graph for evaluating the accelerated life of the multilayer ceramic capacitor according to Example 1.

[0037] Fig.10 is a graph for evaluating the accelerated life of the multilayer ceramic capacitor according to Comparative Example 1. DETAILED DESCRIPTION

[0038] 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 relevant to the description will be omitted, and throughout the specification, the same or similar constituent elements will be represented by the same reference numerals. In addition, in the accompanying drawings, some constituent elements are exaggerated, omitted or schematically shown, and the size of each constituent element does not fully reflect the actual size.

[0039] The accompanying drawings are provided only to facilitate understanding of the embodiments disclosed in this specification and should not be interpreted as limiting the spirit disclosed in this specification. It should be understood that the present disclosure includes all modifications, equivalents, and replacements without departing from the scope and spirit of the present disclosure.

[0040] 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 these terms. The terms are used only for the purpose of distinguishing one constituent element from another constituent element.

[0041] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "above" another element, it can be directly on the other element, or there can 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 this specification, the words "on..." or "above..." mean disposed on or below an object portion, and do not necessarily mean disposed on the upper side of an object portion based on the direction of gravity.

[0042] In this specification, terms such as "include" or "have" are intended to specify the presence of features, numbers, steps, operations, constituent elements, components and / or combinations thereof described in this specification, and should be understood as not excluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, constituent elements, components and / or combinations thereof. In addition, unless explicitly described to the contrary, the words "include", "comprise" or "have" will be understood to imply the inclusion of the elements described but not the exclusion of any other elements.

[0043] In addition, throughout the specification, the term "on a plane" means viewing the target site from above, and "on a cross section" means viewing a cross section formed by vertically cutting the target site from the side.

[0044] Throughout the specification, when it is described that a component is “connected” to another component, the component may be “directly connected” to the other component, may be “connected” to the other component through a third component, or may be physically or electrically connected to the other component, and “connected” may include the case where components that are substantially integrated into one body may be connected to each other even though they are referred to by different names according to position or function.

[0045] In the following, reference will be made to Figures 1 to 3 A multilayer ceramic capacitor according to an embodiment is described.

[0046] 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 a multilayer ceramic capacitor taken along line II' in FIG. Figure 3 is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor taken along line II-II' in FIG.

[0047] Figures 1 to 3 The L axis, W axis and T axis shown 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 constituent element having a sheet shape. For example, the thickness direction (T axis direction) may be used as the same concept as the stacking direction of the dielectric layer 111 stack. The length direction (L axis direction) may be a direction extending in parallel with the wide surface (main surface) of the constituent element having a sheet shape, 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 in which the first external electrode 131 and the second external electrode 132 are opposite to each other. The width direction (W axis direction) is a direction extending in parallel with the wide surface (main surface) of the constituent element having a sheet shape, 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 constituent element having a sheet shape in the length direction (L axis direction) may be greater than the length of the constituent element having a sheet shape in the width direction (W axis direction).

[0048] Reference Figures 1 to 3 , the multilayer ceramic capacitor 100 according to the embodiment includes a capacitor body 110 and external electrodes 131 and 132 disposed outside the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 disposed at both ends of the capacitor body 110 opposite to each other in the length direction (L-axis direction).

[0049] For example, the capacitor body 110 may have an approximately hexahedral shape.

[0050] 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.

[0051] For example, the first surface as the 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 protruding middle portion, and the corners as the boundaries of the surfaces may be rounded.

[0052] 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.

[0053] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrode layers (also referred to as "internal electrodes") 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and first internal electrodes 121 and second internal electrodes 122 alternately disposed in a thickness direction (T-axis direction), and the dielectric layer 111 is interposed between the first internal electrodes 121 and the second internal electrodes 122.

[0054] 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).

[0055] The capacitor body 110 may include an active region (also referred to as an "active portion"). The active region is a region where the dielectric layer 111 and the internal electrode layers 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 along the thickness direction (T-axis direction) overlap.

[0056] In addition, the capacitor body 110 may further include a cover portion and a side edge portion.

[0057] The covering portion may be an edge portion in the thickness direction and may be disposed at the upper and lower surfaces of the active region in the thickness direction (T-axis direction). The covering portion may be a single dielectric layer 111 or two or more dielectric layers 111 stacked on the upper and lower surfaces of the active region, respectively.

[0058] The side edge portions may be referred to as side surface covering portions, and may be respectively provided at two side end portions of the effective area that are opposite to each other in the width direction (W-axis direction). The side edge portions may be formed by applying the conductive paste layer on the surface of the dielectric green sheet only on some areas of the surface of the dielectric green sheet and not applying the conductive paste layer on both side surfaces of the surface of the dielectric green sheet, then stacking the dielectric green sheets and firing the stacked dielectric green sheets, but the present disclosure is not limited to this formation method.

[0059] 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.

[0060] The dielectric layer 111 includes a plurality of dielectric grains.

[0061] Will refer to Figure 4 A dielectric die according to an embodiment is described.

[0062] Figure 4 is a schematic diagram illustrating the structure of one dielectric grain within a dielectric layer according to an embodiment.

[0063] Reference Figure 4 At least one of the plurality of dielectric grains includes a core portion 10 and a shell portion 20 surrounding at least a portion of the core portion 10 .

[0064] The core portion 10 may include a barium titanate-based main component including barium (Ba) and titanium (Ti).

[0065] The shell part 20 may include a barium titanate-based main component including barium (Ba) and titanium (Ti) and a subcomponent including tin (Sn).

[0066] The barium titanate-based main component contained in the core portion 10 and the shell portion 20 is a dielectric matrix material, has a high dielectric constant, and contributes to the formation of the dielectric constant of the multilayer ceramic capacitor 100 .

[0067] 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.

[0068] The shell 20 includes a Sn concentrated region A and a Sn non-concentrated region B. The Sn concentrated region A contains Sn and is a region with a relatively high Sn concentration. The Sn non-concentrated region B is a region that does not contain Sn or contains Sn at a relatively low concentration.

[0069] Specifically, the shell portion 20 may include a Sn concentrated region A having a high Sn concentration (a high Sn atom % content) and a Sn non-concentrated region B having a relatively low Sn concentration (a lower Sn atom % content than that of the Sn concentrated region A).

[0070] Generally, in order to improve the reliability of multilayer ceramic capacitors, the size of the dielectric grains must be small and the number of grains in each dielectric layer must be large. However, due to the thin thickness of the thin-layered dielectric layer, there may be a situation where there are only 1 to 2 dielectric grains in each layer due to the grain growth of the dielectric grains. Therefore, the reliability may be degraded. According to an embodiment, the grain growth of the dielectric grains can be suppressed by doping tin (Sn) into the barium titanate-based main component. In addition, because the band gap energy of tin (Sn) is greater than the band gap energy of the barium titanate-based main component, if the Sn concentration area A exists in the shell portion 20 within the dielectric grain, the tin (Sn) may be concentrated, so that the grain boundary resistance increases.

[0071] In other words, if there are Sn concentrated areas A with high tin (Sn) concentration and Sn non-concentrated areas B with relatively low tin (Sn) concentration in the shell 20 within the dielectric grains, the reliability can be improved by suppressing the grain growth of the dielectric grains and increasing the resistance of the grain boundaries, which is beneficial to improving the reliability of small multilayer ceramic capacitors with thin dielectric layers.

[0072] Specifically, the atomic ratio of tin (Sn) contained in the Sn concentrated region A to the tin (Sn) contained in the Sn non-concentrated region B may be 2.0 to 6.0, 2.1 to 5.5, or 2.2 to 5.0. If the atomic ratio is within the above range, the reliability of a small multilayer ceramic capacitor with a thin dielectric layer can be improved by suppressing the grain growth of dielectric grains and increasing the resistance of grain boundaries.

[0073] The shell portion 20 may be a region with a depth of 15 nm to 25 nm or 17 nm to 23 nm from the outermost portion of the dielectric grain to the inside of the dielectric grain. That is, the thickness t of the shell portion 20 may be 15 nm to 25 nm or 17 nm to 23 nm.

[0074] The thickness t of the shell 20, the Sn concentrated region A and the Sn non-concentrated region B present in the shell 20, the atom % of Sn in each of the Sn concentrated region A and the Sn non-concentrated region B, the atomic ratio of tin (Sn) between the Sn concentrated region A and the Sn non-concentrated region B, the length of the Sn concentrated region A, and the percentage of dielectric grains having the Sn concentrated region A in the dielectric layer can be confirmed by transmission electron microscopy (TEM)-energy dispersive spectrometer (EDS) line analysis. Even if not described in the present disclosure, other methods and / or tools known to those of ordinary skill in the art may be used.

[0075] Transmission electron microscope (TEM)-energy dispersive spectrometer (EDS) line analysis can be performed by the following method. The following cross-sectional sample can be obtained: after the multilayer ceramic capacitor 100 is placed in the epoxy resin mixed solution and the epoxy resin mixed solution is cured, the surface (WT surface) of the capacitor body 110 in the W-axis direction and the T-axis direction is polished to a 1 / 2 depth position in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber so that the effective part where the dielectric layer 111 and the internal electrode layers 121 and 122 alternate with each other is observed. Subsequently, the effective part of the cross-sectional sample can be measured using a transmission electron microscope (TEM) so that at least one layer (for example, 1 to 5 layers) of the dielectric layer 111 is visible. For example, TEM can measure the effective part of the cross-sectional sample in an area of ​​about 300nm×300nm in the dielectric layer 111 under the condition of an acceleration voltage of 200kV using a Xe focused ion beam (FIB). Next, in the TEM image of the measured cross-sectional sample, EDS line analysis is performed on a straight line segment from one outermost point of the dielectric grain through the center of the dielectric grain to the other outermost point of the dielectric grain. Through EDS line analysis, the core-shell structure, the atomic ratio of tin (Sn) between the Sn concentrated area A and the Sn non-concentrated area B, etc. can be confirmed.

[0076] In the transmission electron microscope (TEM)-energy dispersive spectrometer (EDS) line analysis performed by the above method, the Sn concentrated region A may be a region where a peak with the highest atom % of tin (Sn) appears.

[0077] In the Sn concentrated region A, tin (Sn) may be included in an amount of 0.1 atom% to 3 atom% or 0.5 atom% to 2.8 atom% based on the total amount of the shell 20 (e.g., the total amount of the elements of Ba, Ti, O, and Sn in the shell 20). In addition, in the Sn non-concentrated region B, tin (Sn) may be included in an amount of 0.8 atom% or less, 0.01 atom% to 0.8 atom% or 0.1 atom% to 0.6 atom% based on the total amount of the shell 20 (e.g., the total amount of the elements of Ba, Ti, O, and Sn in the shell 20). If the tin (Sn) in each of the Sn concentrated region A and the Sn non-concentrated region B is included within the above content range, the grain growth of the dielectric grains can be suppressed, and the resistance of the grain boundary can be increased, thereby ensuring high reliability of a small multilayer ceramic capacitor with a thin dielectric layer.

[0078] The Sn concentration region A may exist in a shape having a predetermined length l and a predetermined thickness.

[0079] The length l of the Sn concentrated region A may be 40% to 100%, 50% to 100%, 60% to 100%, or 45% to 73% of the major axis length of the dielectric grain. If the length of the Sn concentrated region A is within this range, the resistance characteristics of the grain boundary may be improved.

[0080] In one dielectric grain, specifically, in the shell portion 20 of one dielectric grain, one to four Sn concentration regions A or two to three Sn concentration regions A may exist.

[0081] In addition, on a TEM image having 30 to 50 dielectric grains in one dielectric layer 111, the Sn concentration region A may be present in an amount corresponding to 30% to 100% of the number of dielectric grains. If the Sn concentration region A is present in the dielectric layer 111 in the above amount range, the grain growth of the dielectric grains may be suppressed, the resistance of the grain boundaries may be increased, and thus the reliability of a small multilayer ceramic capacitor with a thin dielectric layer may be improved. The TEM image may be measured in an area of ​​about 1.3 μm×1.3 μm visible in the dielectric layer 111 using a Xe focused ion beam (FIB) at an acceleration voltage of 200 kV.

[0082] According to the embodiment, the average grain size of at least one dielectric grain may be 80nm to 160nm or 90nm to 150nm. If the average grain size of the dielectric grains is within the above range, the grain growth of the dielectric grains can be suppressed, thereby improving the reliability of a small multilayer ceramic capacitor with a thin dielectric layer.

[0083] The average grain size of the dielectric grains can be obtained by scanning electron microscopy (SEM) analysis. Specifically, a cross-sectional sample can be obtained as follows: after the multilayer ceramic capacitor is placed in an epoxy resin mixed solution and the epoxy resin mixed solution is cured, the surface (WT surface) of the capacitor body 110 in the W-axis direction and the T-axis direction is polished to a 1 / 2 point in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber so that the effective portion where the dielectric layer 111 and each inner electrode layer alternate with each other is observed. Subsequently, the cross-sectional sample can be measured by a scanning electron microscope (SEM) so that at least two dielectric layers are visible in the effective portion of the cross-sectional sample. For example, the SEM can be a Verios G4 product from Thermo Fisher Scientific Inc., and the SEM can use a Xe focused ion beam (FIB) under an accelerating voltage of 200kV to measure the effective portion of the cross-sectional sample in an area of ​​about 2.2μm×2.2μm where two dielectric layers are visible. The average grain size of the dielectric grains can be obtained by calculating the average value by measuring the diameter of the longest axis of at least 100 dielectric grains in the SEM image of the cross-sectional sample. Even if not described in the present disclosure, other methods and / or tools known to those of ordinary skill in the art can be used.

[0084] Tin (Sn) may be included in an amount of 0.01 to 5 parts by mole based on 100 parts by mole of the barium titanate-based main component in the shell portion 20. If tin (Sn) within the above content range is included in the shell portion 20, grain growth of dielectric grains may be suppressed even in a thinned dielectric layer, so that the number of dielectric grains per dielectric layer increases. Therefore, reliability may be improved.

[0085] The subcomponents included in the shell part 20 may include dysprosium (Dy), terbium (Tb), manganese (Mn), vanadium (V), barium (Ba), silicon (Si), aluminum (Al), calcium (Ca), or a combination thereof, in addition to tin (Sn).

[0086] Based on 100 parts by mole of the barium titanate-based main component, dysprosium (Dy) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. Based on 100 parts by mole of the barium titanate-based main component, terbium (Tb) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. Based on 100 parts by mole of the barium titanate-based main component, manganese (Mn) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. Based on 100 parts by mole of the barium titanate-based main component, vanadium (V) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. Based on 100 parts by mole of the barium titanate-based main component, barium (Ba) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. Based on 100 parts by mole of the barium titanate-based main component, silicon (Si) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. Based on 100 parts by mole of the barium titanate-based main component, aluminum (Al) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. Based on 100 parts by mole of the barium titanate-based main component, calcium (Ca) may be included in an amount of 0.01 to 5 parts by mole or 0.1 to 4 parts by mole. If each sub-component is included within this content range, the reliability of the thinned dielectric layer can be improved. The contents of tin (Sn), dysprosium (Dy), terbium (Tb), manganese (Mn), vanadium (V), barium (Ba), silicon (Si), aluminum (Al), and calcium (Ca) based on 100 parts by mole of the barium titanate-based main component can be obtained by SEM-EDS analysis. Even if not described in the present disclosure, other methods and / or tools known to those of ordinary skill in the art may be used. The content of each of tin (Sn), dysprosium (Dy), terbium (Tb), manganese (Mn), vanadium (V), barium (Ba), silicon (Si), aluminum (Al), and calcium (Ca) (if present) may substantially correspond to the content of each component present in the dielectric paste used to form the dielectric layer.

[0087] The average thickness of the dielectric layer 111 may be 0.1 μm to 8.0 μm or 0.3 μm to 3.0 μm. If the average thickness of the dielectric layer 111 is within this range, a small multilayer ceramic capacitor with a thinned dielectric layer can ensure high reliability.

[0088] The average thickness of the dielectric layer 111 can be measured by the following method: the multilayer ceramic capacitor 100 is placed in an epoxy resin mixed solution, the epoxy resin mixed solution is cured, the multilayer ceramic capacitor is polished, and then the multilayer ceramic capacitor polished by ion milling is analyzed by 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 10kV and 0.2nA, the analysis magnification can be 100 times, and at least 1 layer or more layers (for example, 3 layers or more layers, 5 layers or more layers, or 10 layers 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 interval of the ten points can be adjusted according to the ratio of the scanning electron microscope (SEM) image. For example, the intervals between the ten points may be 1 μm to 100 μm, 1 μm to 50 μm, or 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.

[0089] 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 to face each other along the T-axis direction, and the dielectric layer 111 is interposed between the first inner electrode 121 and the second inner electrode 122, and one end of each of the first inner electrode 121 and the second inner electrode 122 may be exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0090] The first and second internal electrodes 121 and 122 may be electrically insulated from each other by a dielectric layer 111 disposed between the first and second internal electrodes 121 and 122 .

[0091] Ends of the first and second internal electrodes 121 and 122 , respectively, which are 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.

[0092] Each of the first and second internal electrodes 121 and 122 may include a conductive metal, and for example, each of the first and second internal electrodes 121 and 122 may include a metal such as Ni, Cu, Ag, Pd, Au, etc., or an alloy thereof (eg, Ag—Pd alloy).

[0093] 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 .

[0094] 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.

[0095] The average thickness of each of the first and second internal electrodes 121 and 122 may be in the range of 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, its description is omitted.

[0096] The capacitor body 110 may be formed by firing a stacked body in which a plurality of dielectric layers 111 and internal electrode layers 121 and 122 are stacked.

[0097] 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.

[0098] 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 an overlapped area in which the first and second internal electrodes 121 and 122 overlap each other in the T-axis direction in the active region.

[0099] The first outer electrode 131 may include a first connection portion arranged on the third surface of the capacitor body 110 to be connected to the first inner electrode 121, and a first band portion arranged at a corner where the third surface of the capacitor body 110 intersects with the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110, and the second outer electrode 132 may include a second connection portion arranged on the fourth surface of the capacitor body 110 to be connected to the second inner electrode 122, and a second band portion arranged at a corner where the fourth surface of the capacitor body 110 intersects with the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110.

[0100] The first and second band portions may extend from the first and second connecting portions to a portion of the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 , respectively. The first and second band portions may be used to improve adhesion strength of the first and second external electrodes 131 and 132 .

[0101] 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.

[0102] The sintered metal layer may include conductive metal and glass.

[0103] The conductive metal may include copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), their alloys or combinations thereof, for example, the conductive metal including copper (Cu) may mean that the conductive metal includes copper (Cu) alone or a copper (Cu) alloy. If the conductive metal includes copper, a metal other than copper may be included in an amount of 5 mol parts or less relative to 100 mol parts of copper.

[0104] The glass may include a composition of mixed oxides, for example, the composition may be 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 one or more 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 one or more selected from the group consisting of lithium (Li), sodium (Na) and potassium (K), and the alkaline earth metal may be one or more selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba).

[0105] Alternatively, the conductive resin layer may be formed on the sintered metal layer, for example, 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, and in this case, the conductive resin layer may directly contact the capacitor body 110.

[0106] 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 (i.e., the band portion) where the conductive resin layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 may be greater than the length of the region (i.e., the band portion) where the sintered metal layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. In other words, the conductive resin layer may be formed on the sintered metal layer, and may be formed to completely cover the sintered metal layer.

[0107] The conductive resin layer includes resin and conductive metal.

[0108] The resin included in the conductive resin layer is not particularly limited as long as it has adhesiveness and impact absorption and can be 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.

[0109] The conductive metal included in the conductive resin layer serves to be electrically connected with the first and second internal electrodes 121 and 122 or the sintered metal layer.

[0110] 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 mixture of a flake shape and a spherical shape.

[0111] Here, the spherical shape may include a shape that is not a completely spherical shape, for example, a shape having a ratio of the length of the major axis to the minor axis (major axis / minor axis) of less than or equal to 1.45. The powder having a flake shape refers to a powder having a flat and elongated shape, and the flake shape is not particularly limited, for example, the flake shape may include a shape having a ratio of the length of the major axis to the minor axis (major axis / minor axis) of greater than or equal to 1.95.

[0112] Each of the first and second external electrodes 131 and 132 may further include a plating layer disposed outside the conductive resin layer.

[0113] The plating layer may include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb) or alloys thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, may have a shape in which a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially stacked, and may have a shape in which a tin (Sn) plating layer, a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially stacked. In addition, the plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0114] The plating layer may improve the mountability of the multilayer ceramic capacitor 100 to the substrate, structural reliability, durability with respect to the outside, heat resistance, or equivalent series resistance (ESR).

[0115] Hereinafter, a method of manufacturing the multilayer ceramic capacitor 100 according to the embodiment will be described.

[0116] The multilayer ceramic capacitor 100 according to the embodiment can be manufactured by the following steps: a step of preparing a dielectric slurry by mixing a barium titanate-based main component powder and a subcomponent powder including a tin (Sn) compound, a step of manufacturing a dielectric green sheet using the dielectric slurry 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 a dielectric green sheet on which a conductive paste layer is formed and a dielectric green sheet on which no conductive paste layer is formed, a step of manufacturing a capacitor body including a dielectric layer and an inner electrode layer by firing the dielectric green sheet stack, and a step of forming an outer electrode on an outer surface of the capacitor body.

[0117] First, a dielectric slurry is prepared by mixing a barium titanate-based main component powder and a sub-component powder including a tin (Sn)-containing compound.

[0118] The barium titanate-based main component powder may be prepared by mixing a titanium (Ti) precursor and a barium (Ba) precursor.

[0119] The titanium (Ti) precursor may be titanium oxide, titanium salt, titanium alkoxide, etc. For example, the titanium (Ti) precursor may include titanium dioxide, titanium diisopropoxide diacetyl acetonate (TPA), titanium alkoxide, or a combination thereof.

[0120] The barium (Ba) precursor may include BaO 2 、BaTiO 3 、BaCO 3 , BaO or a combination thereof.

[0121] The barium (Ba) precursor may be included in an amount of 0.9 to 1.1 moles based on 1 mole of the titanium (Ti) precursor.

[0122] The tin (Sn) compound as the subcomponent powder may be an oxide, a nitride, or a salt compound, or may be used in the form of a sol dispersed in an organic solvent.

[0123] Based on 100 parts by mole of the barium titanate-based main component powder, the tin (Sn) compound may be mixed in an amount of 0.01 to 5 parts by mole or 0.1 to 3 parts by mole. If the tin (Sn) compound is mixed within this content range, the reliability of a small multilayer ceramic capacitor with a thin dielectric layer can be improved by suppressing the grain growth of dielectric grains.

[0124] The auxiliary component powder may further include dysprosium (Dy)-containing compounds, terbium (Tb)-containing compounds, manganese (Mn)-containing compounds, vanadium (V)-containing compounds, barium (Ba)-containing compounds, silicon (Si)-containing compounds, aluminum (Al)-containing compounds, calcium (Ca)-containing compounds, or combinations thereof.

[0125] Based on 100 molar parts of the barium titanate-based main component powder, a dysprosium (Dy) compound may be included in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts. Based on 100 molar parts of the barium titanate-based main component powder, a terbium (Tb) compound may be included in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts. Based on 100 molar parts of the barium titanate-based main component powder, a manganese (Mn) compound may be included in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts. Based on 100 molar parts of the barium titanate-based main component powder, a vanadium (V) compound may be included in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts. Based on 100 molar parts of the barium titanate-based main component powder, a barium (Ba) compound may be included in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts. Based on 100 molar parts of barium titanate-based main component powder, a silicon (Si) compound in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts may be included. Based on 100 molar parts of barium titanate-based main component powder, an aluminum (Al) compound in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts may be included. Based on 100 molar parts of barium titanate-based main component powder, a calcium (Ca) compound in an amount of 0.01 to 5 molar parts or 0.1 to 4 molar parts may be included. If each auxiliary component powder is included within this content range, the reliability of a small multilayer ceramic capacitor with a thin dielectric layer can be improved. The content of the corresponding compound of the above-mentioned auxiliary component is calculated based on the content of the effective element (e.g., Sn, Dy, Tb, Mn, V, Ba, Si, Al, Ca) therein, regardless of the addition form of the corresponding compound.

[0126] The dielectric slurry may be prepared by further mixing additives (eg, 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 powder, the dispersant may be mixed in an amount of 0.1 to 5 parts by weight or 0.3 to 3 parts by weight. If the dispersant is mixed within this content range, the dispersibility of the dielectric slurry may be excellent, and the amount of impurities included in the manufactured dielectric layer may be reduced.

[0128] For example, the binder may be an acrylic resin, a polyvinyl butyl resin, a polyvinyl acetal resin, an ethyl cellulose resin, etc. The binder may be added in an amount of 0.1 to 50 parts by weight or 3 to 30 parts by weight based on 100 parts by weight of the barium titanate-based main component powder. If the binder is mixed within this content range, the dispersibility of the dielectric slurry may be excellent, and the amount of impurities included in the manufactured dielectric layer may be reduced.

[0129] For example, the plasticizer may include 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.), glycol 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.). Based on 100 parts by weight of the barium titanate-based main component powder, the plasticizer may be added in an amount of 0.1 to 20 parts by weight or 1 to 10 parts by weight. If the plasticizer is mixed within this content range, the dispersibility of the dielectric slurry may be excellent, and the amount of impurities included in 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.), a ketone solvent (such as ethylene glycol, diethylene glycol, etc.), a glycol 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 use an alcohol solvent or an aromatic solvent. Based on 100 parts by weight of the barium titanate-based main component powder, the solvent may be mixed in an amount of 50 parts by weight to 1000 parts by weight or 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 barium titanate-based main component powder and the auxiliary component powder 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 with a diameter of 0.1 mm to 10 mm can be used for wet mixing for 8 to 48 hours or 10 to 24 hours.

[0132] The prepared dielectric slurry forms a dielectric layer after firing.

[0133] The method for molding the prepared dielectric slurry into a sheet shape 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 obtain a dielectric green sheet by drying the molded body.

[0134] In order to form a conductive paste that becomes an inner electrode layer after firing, the conductive paste can be prepared by mixing a conductive powder made of a conductive metal or its alloy, a binder and a solvent. In addition, if necessary, barium titanate powder can be mixed together as a co-material. The co-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 or transfer methods such as screen printing.

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

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

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

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

[0139] Next, the 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 layer. For example, the temperature rise rate during the binder removal treatment may be 5°C / hour to 300°C / hour, the treatment temperature during the binder removal treatment may be 180°C to 400°C, and the temperature maintenance 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 composition of the dielectric layer or the main component composition of the inner electrode. For example, firing may be performed at a temperature of 1100°C to 1400°C or 1150°C to 1300°C. Alternatively, firing may be performed at a temperature greater than 1160°C and less than or equal to 1220°C. In addition, firing may be performed for 0.5 hours to 8 hours or 1 hour to 3 hours. In addition, firing may be performed in a reducing atmosphere (e.g., an atmosphere of a humidified mixed gas containing 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 under 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 annealing may be 950°C to 1150°C, the time during annealing may be greater than 0 hours and less than or equal to 20 hours, and the heating rate during annealing may be 50°C / hour to 500°C / hour. The annealing atmosphere may be humidified nitrogen (N 2 ) atmosphere, the oxygen partial pressure in the annealing atmosphere can 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, nitrogen gas, mixed gas, etc. may be humidified using a humidifier, etc. 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] Alternatively, surface treatment such as sandblasting, laser irradiation, barrel polishing, etc. may be performed on the third and fourth surfaces of the manufactured capacitor body 110. By performing the surface treatment, the ends of the first and second inner electrodes may be exposed on the third and fourth surfaces. Therefore, the electrical bonding between the first and second outer electrodes and the first and second inner electrodes may become good, and an alloy portion may be easily formed.

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

[0146] For example, a paste for forming a sintered metal layer may be applied to the external electrode, and then the applied paste may be 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 that of the conductive metal and glass described above, so the repeated description thereof 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 use ethyl cellulose, acrylic acid, butyral, etc., and for example, the solvent may use an organic solvent (e.g., terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0148] The method for applying the paste for forming the sintered metal layer to the outer surface of the capacitor body 110 may include a dipping method, various printing methods such as screen printing, a coating method using a dispenser, 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 portions of the first, second, fifth, or sixth surfaces where the band portion of each of the first and second external electrodes is to be formed.

[0149] Thereafter, the capacitor body 110 coated with the paste for forming the sintered metal layer 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 a 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 may optionally include conductive metal and resin. The description of conductive metal and resin is the same as the conductive metal and resin described above, so the 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, adhesive may be ethyl cellulose, acrylic acid, butyral, etc., and for example, solvent may be an organic solvent (for example, terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0152] For example, 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 paste, 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 outside of the conductive resin layer.

[0154] For example, the plated layer may be formed by a plating method, or the plated layer 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] Examples 1 to 3 and Comparative Examples 1 to 5

[0158] By mixing barium titanate (BaTiO 3 ) and tin oxide (SnO 2 ) and dysprosium oxide (Dy 2 O 3 ) to prepare a dielectric slurry. In this case, based on 100 mol parts of barium titanate (BaTiO 3 ), tin oxide (SnO 2 ) and dysprosium oxide (Dy 2 O 3 ) were mixed in 1.5 mol parts each. Zirconium (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 mixed, and then mechanical grinding is performed.

[0159] The prepared dielectric slurry was used to produce a dielectric green sheet using a roll-on coating machine of a die-discharging type.

[0160] 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=0.39 mm×0.69 mm×0.39 mm) was manufactured by laminating and pressing the dielectric green sheets having the conductive paste layer formed thereon.

[0161] The dielectric green sheet stack is subjected to a binder removal process at 400° C. or less in a nitrogen atmosphere, and a firing temperature of 1300° C. or less in a hydrogen atmosphere. 2 ) concentration is less than or equal to 1.0%. Specifically, Comparative Examples 1 to 3 are fired at a temperature greater than or equal to 1140°C and less than or equal to 1160°C, Examples 1 to 3 are fired at a temperature greater than 1160°C and less than or equal to 1220°C, and Comparative Examples 4 and 5 are fired at a temperature greater than 1220°C and less than or equal to 1240°C.

[0162] Subsequently, external electrodes were formed on the outer surface of the capacitor body including the dielectric layer having a thickness of 400 nm to 450 nm to manufacture a multilayer ceramic capacitor.

[0163] Evaluation 1: TEM analysis

[0164] Transmission electron microscope (TEM) analysis was performed on the multilayer ceramic capacitor manufactured in Example 1, and the results are shown in FIG. Figure 5 middle.

[0165] Specifically, a cross-sectional sample is obtained as follows: after the multilayer ceramic capacitor 100 manufactured in Example 1 is placed in an epoxy resin mixed solution and the epoxy resin mixed solution is cured, the surface (WT surface) of the capacitor body 110 in the W-axis direction and the T-axis direction is polished to a 1 / 2 depth position in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber so that an effective area where the dielectric layer 111 and each internal electrode layer alternate with each other is observed. Subsequently, a transmission electron microscope (TEM) is used to measure the effective area of ​​the cross-sectional sample so that at least one layer of the dielectric layer 111 is visible. TEM uses a Xe focused ion beam (FIB) under an accelerating voltage condition of 200 kV to measure the effective portion of the cross-sectional sample in an area of ​​about 1.3 μm×1.3 μm where the dielectric layer 111 is visible.

[0166] Figure 5 is a TEM image of the dielectric layer according to Example 1.

[0167] Reference Figure 5 , it can be seen that the dielectric layer according to Example 1 includes a plurality of dielectric grains, and at least one of the plurality of dielectric grains has a Sn concentrated region with a high Sn concentration in the shell portion of the core-shell structure.

[0168] Evaluation 2: TEM-EDS line analysis

[0169] Transmission electron microscope (TEM)-energy dispersive spectrometer (EDS) line analysis was performed on the multilayer ceramic capacitors manufactured in Examples 1 to 3 and Comparative Examples 1 to 5, and the results are shown in FIG. Fig. 6A and Figure 6B And in Table 1 below.

[0170] Specifically, using the multilayer ceramic capacitors manufactured in Examples 1 to 3 and Comparative Examples 1 to 5, a cross-sectional sample was obtained by the same method as in Evaluation 1. Subsequently, a transmission electron microscope (TEM) was used to measure the effective area of ​​the cross-sectional sample so that at least one layer of the dielectric layer 111 was visible. The TEM measured the effective portion of the cross-sectional sample in an area of ​​about 300 nm×300 nm within the dielectric layer 111 using a Xe focused ion beam (FIB) under an accelerating voltage of 200 kV. Subsequently, as Fig. 6A As shown, in the TEM image of the measured cross-sectional sample, EDS line analysis is performed on a straight line segment from one outermost point of the dielectric grain through the center of the dielectric grain to the other outermost point of the dielectric grain.

[0171] Fig. 6A is a TEM image showing dielectric grains within the dielectric layer according to Example 1, and Figure 6B yes Fig. 6A EDS line analysis diagram of dielectric grains.

[0172] Reference Fig. 6A and Figure 6B It can be seen that in the case of Example 1, one dielectric grain includes a core and a shell, and the shell is a region from the outermost portion of the dielectric grain to a depth of about 20 nm inside the dielectric grain. In addition, it can be seen from the EDS line analysis diagram that the shell includes a Sn concentrated region and a Sn non-concentrated region, the Sn concentrated region is a region where the atom% of tin (Sn) has the highest peak, and the Sn non-concentrated region is a portion including a lower atom% of tin (Sn) than the atom% of the Sn concentrated region.

[0173] Through the above-mentioned TEM-EDS line analysis, the atom% content ratio (ie, atomic ratio) of tin (Sn) between the Sn concentrated region A and the Sn non-concentrated region B shown in the following Table 1 was obtained.

[0174] In the following Table 1, the length ratio of the Sn concentrated region A is the percentage value of the length of the Sn concentrated region A to the major axis length of the dielectric grain. As can be seen from Table 1, the atomic ratio of Sn contained in the Sn concentrated region A to Sn contained in the Sn non-concentrated region B satisfies 2.0 to 6.0.

[0175] (Table 1)

[0176]

[0177] Evaluation 3: SEM analysis

[0178] Scanning electron microscope (SEM) analysis was performed on the multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1 to measure the average grain size of dielectric grains, and the results are shown in FIG. Figure 7 and Figure 8 middle.

[0179] Specifically, the cross-sectional sample is obtained as follows: after the multilayer ceramic capacitor manufactured in Example 1 and Comparative Example 1 is placed in an epoxy resin mixed solution and the epoxy resin mixed solution is cured, the surface (WT surface) of the capacitor body in the W-axis direction and the T-axis direction is polished to 1 / 2 point in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber so that the effective part where the dielectric layer 111 and each inner electrode layer alternate with each other is observed. Subsequently, the cross-sectional sample can be measured by a scanning electron microscope (SEM) so that at least two dielectric layers are visible in the effective part of the cross-sectional sample. The SEM is a Verios G4 product from Thermo Fisher Scientific Inc., and the SEM uses a Xe focused ion beam (FIB) under an accelerating voltage of 200 kV to measure the effective part of the cross-sectional sample in an area of ​​about 2.2 μm×2.2 μm where the two dielectric layers are visible. The average grain size of the dielectric grains is obtained by calculating the average value by measuring the diameter of the maximum long axis of at least 100 dielectric grains in the SEM image of the cross-sectional sample.

[0180] Figure 7 is a SEM image of the dielectric layer according to Example 1, Figure 8 is a SEM image of the dielectric layer of Comparative Example 1.

[0181] Reference Figure 7 and Figure 8 It can be seen that the shell of the dielectric grains includes a Sn concentrated region and a Sn non-concentrated region, and the average grain size (GS) of Example 1 in which the atomic ratio of tin (Sn) in the Sn concentrated region to tin (Sn) in the Sn non-concentrated region is in the range of 2.0 to 6.0 is 120nm, but the average grain size (GS) of Comparative Example 1 is 170nm. It can be seen that the grain growth of the dielectric grains according to the embodiment is suppressed, so that the reliability is improved, which is conducive to improving the reliability of small multilayer ceramic capacitors with thin dielectric layers.

[0182] Evaluation 4: Reliability

[0183] The multilayer ceramic capacitors manufactured in Examples 1 to 3 and Comparative Examples 1 to 5 were subjected to accelerated life evaluation, and the results are shown in Table 2, Fig. 9 and Fig.10 middle.

[0184] Specifically, after 40 sample chips are mounted on the reliability substrate, the failure rate (%) of sample chips that are defective within 10 hours is calculated under the conditions of a temperature of 125°C and a voltage of 6 V. In addition, if the failure rate is 5% or less, it is judged as ○, if the failure rate is greater than 5% and less than or equal to 20%, it is judged as △, and if the failure rate is greater than 20%, it is judged as ×.

[0185] (Table 2)

[0186] Failure rate (%) Judgment result Example 1 5％ ○ Example 2 0％ ○ Example 3 2.5％ ○ Comparative Example 1 32.5％ × Comparative Example 2 25％ × Comparative Example 3 17.5％ △ Comparative Example 4 10％ △ Comparative Example 5 22.5％ ×

[0187] Fig. 9 is a graph for evaluating the accelerated life of the multilayer ceramic capacitor according to Example 1, Fig.10 is a graph for evaluating the accelerated life of the multilayer ceramic capacitor according to Comparative Example 1.

[0188] Refer to Table 2. Fig. 9 and Fig.10 It can be seen that Example 1, in which the shell portion of the dielectric grain includes a Sn concentrated region and a Sn non-concentrated region and the atomic ratio of tin (Sn) in the Sn concentrated region to tin (Sn) in the Sn non-concentrated region is in the range of 2.0 to 6.0, has excellent accelerated life characteristics compared to Comparative Example 1. Therefore, it can be confirmed that the multilayer ceramic capacitor according to the embodiment can have excellent reliability even with a thinned dielectric layer.

[0189] While the disclosure has been described in connection with what are presently considered to be practical embodiments, it should be understood that the disclosure is not limited to the disclosed embodiments, but on the contrary, the disclosure 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 an inner electrode layer; as well as An external electrode, disposed outside the capacitor body, The dielectric layer includes a plurality of dielectric grains, and 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 secondary component, wherein the barium titanate-based main component includes Ba and Ti, and the secondary component includes Sn. wherein the shell portion includes a Sn concentrated region containing Sn and a Sn non-concentrated region containing Sn whose atom% is less than the atom% of Sn in the Sn concentrated region, and The atomic ratio of Sn contained in the Sn concentrated region to Sn contained in the Sn non-concentrated region is 2.0 to 6.

0.

2. The multilayer ceramic capacitor according to claim 1, wherein The shell portion is a region having a depth of 15 nm to 25 nm from the outermost portion of the at least one dielectric grain to the inside of the at least one dielectric grain.

3. The multilayer ceramic capacitor according to claim 1, wherein In a TEM-EDS line analysis of a straight line segment from one outermost point of the at least one dielectric grain through the center of the at least one dielectric grain to another outermost point of the at least one dielectric grain, the Sn concentration region has a peak with the highest atom % of Sn.

4. The multilayer ceramic capacitor according to claim 1, wherein: The Sn non-concentration region includes Sn in an amount of 0.8 atom% or less based on the total amount of elements in the shell portion.

5. The multilayer ceramic capacitor according to claim 1, wherein The length of the Sn concentration region is 40% to 100% of the length of the major axis of the at least one dielectric grain.

6. The multilayer ceramic capacitor according to claim 1, wherein The plurality of dielectric grains include 30 to 50 dielectric grains, and 30% to 100% of the 30 to 50 dielectric grains include the Sn concentrated region.

7. The multilayer ceramic capacitor according to claim 1, wherein: The at least one dielectric grain has an average grain size of 80 nm to 160 nm.

8. The multilayer ceramic capacitor according to claim 1, wherein The core portion includes the barium titanate-based main component, and the barium titanate-based main component includes Ba and Ti.

9. The multilayer ceramic capacitor according to claim 1, wherein: Sn is included in an amount of 0.01 parts by mol to 5 parts by mol based on 100 parts by mol of the barium titanate-based main component in the shell portion.

10. The multilayer ceramic capacitor according to claim 1, wherein The auxiliary components further include Dy, Tb, Mn, V, Ba, Si, Al, calcium Ca or a combination thereof.

11. The multilayer ceramic capacitor according to claim 10, wherein: In the shell portion, based on 100 parts by mole of the barium titanate-based main component, comprising Dy in an amount of 0.01 to 5 parts by mole, comprising Tb in an amount of 0.01 to 5 parts by mole, including Mn in an amount of 0.01 to 5 parts by mole, comprising V in an amount of 0.01 to 5 parts by mole, comprising Ba in an amount of 0.01 to 5 parts by mole, comprising Si in an amount of 0.01 to 5 parts by mole, comprising Al in an amount of 0.01 to 5 parts by mole, including Ca in an amount of 0.01 to 5 parts by mole, or A combination of them.

12. The multilayer ceramic capacitor according to claim 5, wherein The length of the Sn concentration region is 43% to 75% of the length of the major axis of the at least one dielectric grain.

13. A method of manufacturing a multilayer ceramic capacitor, comprising: preparing a dielectric slurry by mixing a barium titanate-based main component powder and a subcomponent powder including a Sn-containing compound; manufacturing a dielectric green sheet from the dielectric slurry, and forming a conductive paste layer on a surface of the dielectric green sheet; manufacturing a dielectric green sheet laminate by laminating a plurality of dielectric green sheets on which the conductive paste layer is 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 the outer surface of the capacitor body, The dielectric layer includes a plurality of dielectric grains, and at least one of the 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 secondary component, wherein the barium titanate-based main component includes Ba and Ti, and the secondary component includes Sn. wherein the shell portion includes a Sn concentrated region containing Sn and a Sn non-concentrated region containing Sn whose atom% is less than the atom% of Sn in the Sn concentrated region, and The atomic ratio of Sn contained in the Sn concentrated region to Sn contained in the Sn non-concentrated region is 2.0 to 6.

0.

14. The method according to claim 13, wherein: The Sn-containing compound is mixed in an amount of 0.01 parts by mol to 5 parts by mol based on 100 parts by mol of the barium titanate-based main component powder.

15. The method according to claim 13, wherein: The auxiliary component powder further includes a Dy-containing compound, a Tb-containing compound, a Mn-containing compound, a V-containing compound, a Ba-containing compound, a Si-containing compound, an Al-containing compound, a Ca-containing compound or a combination thereof.

16. The method according to claim 15, wherein: Based on 100 parts by mole of the barium titanate-based main component powder, comprising a Dy-containing compound in an amount of 0.01 to 5 parts by mole, comprising a Tb-containing compound in an amount of 0.01 to 5 parts by mole, comprising a Mn-containing compound in an amount of 0.01 to 5 parts by mole, comprising a V-containing compound in an amount of 0.01 to 5 parts by mole, comprising a Ba-containing compound in an amount of 0.01 to 5 parts by mole, comprising a Si-containing compound in an amount of 0.01 to 5 parts by mole, comprising an Al-containing compound in an amount of 0.01 to 5 parts by mole, comprising a Ca-containing compound in an amount of 0.01 to 5 parts by mole, or A combination of them.

17. The method according to claim 13, wherein: The dielectric green sheet stack is fired at a firing temperature greater than 1160° C. and equal to or less than 1220° C.

18. The method according to claim 13, wherein: The dielectric green sheet stack is fired in an atmosphere having a hydrogen concentration of 1.0% or less.

19. The method according to claim 13, wherein: The dielectric slurry is also mixed with a dispersant. Herein, the dispersant is mixed in an amount of 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the barium titanate-based main component powder.

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