Multilayered capacitor

Abstract

To provide a multilayered capacitor in which a dielectric constant is improved by controlling the average mole ratio of the primary component in the dielectric crystal grain core and the average area ratio of the dielectric crystal grain shell.SOLUTION: A multilayered capacitor according to an embodiment, includes: a capacitor body that includes a dielectric layer and an internal electrode; and an external electrode that is arranged outside the capacitor body. The dielectric layer includes a plurality of dielectric crystal grains containing barium titanate as a main component. At least one of the plurality of dielectric crystal grains has a core-shell structure, and an average mole ratio of barium to titanium in a core of each dielectric crystal grain (Ba / Ti mole ratio) is 0.9975 to 1.0055, and an average number of the cores per unit area (1 μm×1 μm) in the dielectric layer is 25 to 35.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This description relates to a multilayer capacitor.

Background Art

[0002] Recently, as the multifunctionalization and miniaturization of electronic devices have been rapidly progressing, the miniaturization and performance improvement of electronic components have also been rapidly advancing. In addition, the demand for high reliability of electrical devices used in automobiles or network facilities, etc., and electronic components for industrial use has been increasing significantly.

[0003] In order to meet such market demands, the technological development competition of passive components such as inductors, capacitors, or resistors has been accelerating. In particular, many efforts are required to preempt the market in the development of various products of multilayer ceramic capacitors (MLCCs), which are passive components whose applications and usage amounts are continuously increasing.

[0004] Also, a multilayer capacitor is a capacitor manufactured in a form where dielectric layers and internal electrodes are stacked, and is used in various electronic devices such as mobile phones, notebook computers, and LCD TVs. In particular, due to the development of automotive electronic control technology, the demand for vehicle use has been increasing, and as the miniaturization and high functionality of vehicle electronic devices are being carried out, the high-temperature and humidity-resistant characteristics of multilayer capacitors are required.

[0005] BaTiO 3 (barium titanate) is a piezoelectric material and a photoelectric material, and has recently been mainly used in multilayer capacitors. However, the number of companies supplying barium titanate powder globally is limited, and its manufacturing technology is also restricted.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One embodiment provides a multilayer capacitor with improved dielectric constant by controlling the average molar ratio of the main component in the dielectric crystal grains core and the average area ratio of the dielectric crystal grains shell. **Means for Solving the Problems**

[0007] A multilayer capacitor according to one embodiment includes a capacitor body including a dielectric layer and an internal electrode, and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric crystal grains containing barium titanate as a main component. At least one or more of the plurality of dielectric crystal grains have a core-shell structure. The average molar ratio of barium to titanium (Ba / Ti mole ratio) in the core of the dielectric crystal grains is 0.9975 to 1.0055. The average number of the cores per unit area (1 μm × 1 μm) in the dielectric layer is 25 to 35.

[0008] The average molar ratio of barium to titanium (Ba / Ti mole ratio) in the core of the dielectric crystal grains may be 0.9980 to 1.0050.

[0009] The average area ratio of the shell included in one dielectric crystal grain having the core-shell structure to the average area of one dielectric crystal grain having the core-shell structure may be 30% to 50%.

[0010] The average area ratio of the shell included in one dielectric crystal grain having the core-shell structure to the average area of one dielectric crystal grain having the core-shell structure may be 38% to 46%.

[0011] The main component is BaTiO 3 , Ba(Ti,Zr)O 3 , Ba(Ti,Sn)O 3 , (Ba,Ca)TiO 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 combinations thereof can be included.

[0012] The dielectric crystal grains further contain a sub-component, The sub-component can include dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), or combinations thereof.

[0013] The sub-component can further include magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), lanthanum (La), chromium (Cr), hafnium (Hf), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or combinations thereof.

[0014] The dielectric crystal grains contain Dy 2 O 3 0.5 to 1.5 parts by mole, MnO 2 0.05 to 0.15 parts by mole, V 2 O 5 0.05 to 0.15 parts by mole, BaCO 3 1.0 to 2.5 parts by mole, SiO 2 0.5 to 1.0 parts by mole, or Al 2 O 3 0.2 to 1.0 parts by mole as a sub-component can be included.

[0015] The shell contains the total amount of the secondary component in an amount exceeding 0.1 mol and not exceeding 30.0 mol with respect to 100 mol of the main component, and the core can contain the total amount of the secondary component in an amount of 0.1 mol or less with respect to 100 mol of the main component.

[0016] The average diameter of the core may be 50 nm to 500 nm.

[0017] The average thickness of the dielectric layer may be 0.15 μm to 10 μm.

[0018] A multilayer capacitor according to another embodiment includes a capacitor body including a dielectric layer and an internal electrode, and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric crystallites containing barium titanate as a main component. At least one or more of the plurality of dielectric crystallites have a core-shell structure. The average molar ratio (Ba / Ti mole ratio) of barium to titanium in the core of the dielectric crystallite is 0.9975 to 1.0055. The average number of the cores per unit area (1 μm × 1 μm) in the dielectric layer is 27 to 35. The average area ratio of the shell included in one dielectric crystallite having the core-shell structure to the average area of one dielectric crystallite having the core-shell structure is 30% to 50%.

[0019] The average molar ratio (Ba / Ti mole ratio) of barium to titanium in the core of the dielectric crystallite may be 0.9980 to 1.0050.

[0020] The average area ratio of the shell included in one dielectric crystallite having the core-shell structure to the average area of one dielectric crystallite having the core-shell structure may be 38% to 46%.

[0021] The main component is BaTiO 3 、Ba(Ti,Zr)O 3 、Ba(Ti,Sn)O3 , (Ba,Ca)TiO 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 combinations thereof can be included.

[0022] The dielectric crystal grains further contain a sub-component, and the sub-component can include dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), or combinations thereof.

[0023] The dielectric crystal grains contain Dy 2 O 3 in an amount of 0.5 to 1.5 mol parts, MnO 2 in an amount of 0.05 to 0.15 mol parts, V 2 O 5 in an amount of 0.05 to 0.15 mol parts, BaCO 3 in an amount of 1.0 to 2.5 mol parts, SiO 2 in an amount of 0.5 to 1.0 mol parts, or Al 2 O 3 in an amount of 0.2 to 1.0 mol parts as a sub-component.

[0024] The shell contains the entire sub-component in an amount of more than 0.1 mol and not more than 30.0 mol per 100 mol of the main component, and the core can contain the entire sub-component in an amount of not more than 0.1 mol per 100 mol of the main component.

[0025] The average diameter of the core may be 50 nm to 500 nm.

[0026] The average thickness of the dielectric layer may be 0.15 μm to 10 μm.

Advantages of the Invention

[0027] According to the multilayer capacitor of one embodiment, by controlling the average molar ratio of the main component in the dielectric crystal grain core and the average area ratio of the dielectric crystal grain shell, a multilayer capacitor with extremely excellent dielectric constant can be provided.

Brief Description of Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0029] Hereinafter, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it with reference to the attached drawings. In order to clearly explain the present invention in the drawings, parts unnecessary for the explanation are omitted, and the same reference numerals are given to the same or similar components throughout the specification. Also, the attached drawings are only for facilitating the understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the attached drawings, and it must be understood that all modifications, equivalents, and alternatives included in the idea and technical scope of the present invention are included.

[0030] Terms including ordinal numbers such as first, second, etc. can be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0031] When a component is referred to as being "connected" or "attached" to another component, it should be understood that it may be directly connected or attached to the other component, or may be opposite, but there may also be other components in between. On the contrary, when a component is referred to as being "directly connected" or "directly attached" to another component, it should be understood that there are no other components in between.

[0032] Throughout the specification, terms such as "including" or "having" are intended to specify the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that the presence or addition possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded in advance. Therefore, when a part "includes" a certain component, this means that it can further include other components rather than excluding other components unless there is a contrary description.

[0033] FIG. 1 is a perspective view showing a multilayer capacitor 100 according to an embodiment, FIG. 2 is a cross-sectional view of the multilayer capacitor 100 cut along the line I-I' of FIG. 1, and FIG. 3 is an exploded perspective view showing the laminated structure of the internal electrodes in the capacitor body 110 of FIG. 1.

[0034] To clearly explain this embodiment, if directions are defined, the L-axis, W-axis, and T-axis shown in the drawings indicate 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-shaped component, and as an example, it can be used as the same concept as the lamination direction in which the dielectric layer 111 is laminated. The length direction (L-axis direction) may be a direction that extends parallel to the wide surface (main surface) of the sheet-shaped component and is substantially perpendicular to the thickness direction (T-axis direction), and as an example, it may be the direction in which the first external electrode 131 and the second external electrode 132 are located on both sides. The width direction (W-axis direction) may be a direction that extends parallel to the wide surface (main surface) of the sheet-shaped component and is substantially perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length in the length direction (L-axis direction) of the sheet-shaped component may be even longer than the length in the width direction (W-axis direction).

[0035] Referring to FIGS. 1 to 3, the multilayer capacitor 100 according to this embodiment can include a capacitor body 110 and first and second external electrodes 131 and 132 disposed at both ends facing each other in the length direction (L-axis direction) of the capacitor body 110.

[0036] The capacitor body 110 may be, for example, a roughly hexahedral shape.

[0037] In this embodiment, for convenience of explanation, both surfaces of the capacitor body 110 facing each other in the thickness direction (T-axis direction) are defined as the first surface and the second surface, both surfaces connected to the first surface and the second surface and facing each other in the length direction (L-axis direction) are defined as the third surface and the fourth surface, and both surfaces connected to the first surface and the second surface and connected to the third surface and the fourth surface and facing each other in the width direction (W-axis direction) are defined as the fifth surface and the sixth surface.

[0038] As an example, the first surface which is the bottom surface can be the surface facing the mounting direction. Also, the first surface to the sixth surface may be flat, but the present embodiment is not limited thereto. For example, the first surface to the sixth surface may be a convex curved surface at the center, and the corners which are the boundaries of each surface may be rounded.

[0039] The shape, dimensions 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 embodiment.

[0040] The capacitor body 110 is obtained by firing after stacking a plurality of dielectric layers 111 in the thickness direction (T-axis direction), and includes a first internal electrode layer 121 and a second internal electrode layer 122 which are alternately arranged in the thickness direction (T-axis direction) with the plurality of dielectric layers 111 interposed therebetween.

[0041] At this time, the boundaries between the respective adjacent dielectric layers 111 of the capacitor body 110 can be integrated to such an extent that it is difficult to confirm without using a scanning electron microscope (SEM).

[0042] Also, the capacitor body 110 can include an active region and cover regions 112 and 113.

[0043] The active region is a portion that contributes to the formation of the capacitance of the multilayer capacitor 100. As an example, the active region may be a region where the first internal electrode layer 121 or the second internal electrode layer 122 stacked along the thickness direction (T-axis direction) overlaps.

[0044] The cover regions 112 and 113 are margin portions in the thickness direction and can be respectively arranged on the first surface and the second surface sides of the active region in the thickness direction (T-axis direction). Such cover regions 112 and 113 may be formed by laminating a single dielectric layer 111 or two or more dielectric layers 111 on the upper surface and the lower surface of the active region respectively.

[0045] In addition, the capacitor body 110 can further include side cover regions. The side cover regions are margin portions in the width direction and can be respectively arranged on the fifth surface and the sixth surface sides of the active region in the width direction (W-axis direction). Such side cover regions can be formed by applying a conductive paste layer for forming an internal electrode layer only on a partial region of the surface of the dielectric green sheet when applying the conductive paste layer on the surface of the dielectric green sheet, laminating dielectric green sheets on both side surfaces of the surface of the dielectric green sheet where the conductive paste layer is not applied, and then firing.

[0046] The cover regions 112 and 113 and the side cover regions serve to prevent damage to the first internal electrode layer 121 and the second internal electrode layer 122 due to physical or chemical stress.

[0047] FIG. 4 is a diagram schematically showing the structure of the dielectric crystal grains 1111 of the dielectric layer 111. Hereinafter, the dielectric layer 111 will be described in detail with reference to FIG. 4.

[0048] The dielectric layer 111 includes a plurality of dielectric crystal grains 1111.

[0049] The dielectric crystal grains 1111 mainly contain barium titanate. The main component is a dielectric base material, which has a high dielectric constant and contributes to the formation of the dielectric constant of the multilayer capacitor 100.

[0050] As an example, the main component is Ba m TiO 3 (0.995 ≦ m ≦ 1.010), (Ba 1-x Ca x ) m (Ti 1-y Zry )O 3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O 3 (0.995 ≤ m ≤ 1.010, x ≤ 0.10), (Ba 1-x Ca x ) m (Ti 1-y Sn y )O 3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), or it may be a dielectric material containing a combination thereof.

[0051] As an example, the main component is BaTiO 3 , Ba(Ti,Zr)O 3 , Ba(Ti,Sn)O 3 , (Ba,Ca)TiO 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 it can contain a combination thereof.

[0052] The dielectric crystal grains can further contain a sub-component together with the main component.

[0053] The sub-component can contain dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), or a combination thereof.

[0054] In addition, the secondary components can further include magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), lanthanum (La), chromium (Cr), hafnium (Hf), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or combinations thereof.

[0055] For example, the dielectric crystal grains can contain, as secondary components, with respect to 100 mol parts of the main component, Dy 2 O 3 from 0.5 mol part to 1.5 mol parts, MnO 2 from 0.05 mol part to 0.15 mol parts, V 2 O 5 from 0.05 mol part to 0.15 mol parts, BaCO 3 from 1.0 mol part to 2.5 mol parts, SiO 2 from 0.5 mol part to 1.0 mol parts, or Al 2 O 3 from 0.2 mol part to 1.0 mol parts. In this case, relative comparison with respect to dielectric changes is easy.

[0056] There can be portions within the dielectric crystal grains 1111 where the molar ratios of the secondary components to the main component are different from each other. As an example, at least one or more of the plurality of dielectric crystal grains 1111 have a core-shell structure. The dielectric crystal grains 1111 having a core-shell structure include a dielectric core 1111a and a shell 1111b surrounding at least a part of the core 1111a within one dielectric crystal grain 1111.

[0057] The core 1111a and the shell 1111b have different molar ratios of the secondary component to the primary component. For example, the molar ratio of the secondary component to the primary component may change abruptly at the boundary between the core 1111a and the shell 1111b. Thereby, the boundary between the core 1111a and the shell 1111b can be easily distinguished, and this can be confirmed through transmission electron microscopy - energy dispersive X-ray analysis (TEM-EDX).

[0058] As an example, in a cross-section cut from the center in the W-axis direction of the capacitor body 110 in the L-axis direction and the T-axis direction, when performing line analysis on the dielectric crystal grains 1111 of the dielectric layer 111 located at the center of the active region using EDS (Energy Disperse X-Ray Spectrometer) set in a transmission electron microscope (TEM, Transmission Electron Microscope), the core 1111a and the shell 1111b can be distinguished by taking the portion where the overall content of the secondary component starts to increase rapidly in the grain boundary direction on either side of the dielectric crystal grain 1111 from the center of the core 1111a of the dielectric crystal grain 1111 as the boundary between the core 1111a and the shell 1111b.

[0059] Here, the center of the core 1111a can be determined as the point where the maximum minor axis among the maximum major axis of the core 1111a and the minor axis perpendicular to it intersects. Also, the EDS (Energy Disperse X-Ray Spectrometer) line analysis can be performed along the maximum major axis passing through the center of the core 1111a of the dielectric crystal grain 1111. Alternatively, by methods such as binarizing the transmission electron microscope image, the boundary between the core 1111a and the shell or the boundary between the shell and the grain boundary can also be defined by distinguishing the portions with brightness differences.

[0060] As an example, the core 1111a contains the total amount of the secondary components at 0.1 mole part or less with respect to 100 mole parts of the main component, and the shell 1111b can contain the total amount of the secondary components at more than 0.1 mole part and 30.0 mole parts or less, or more than 0.1 mole part and 20.0 mole parts or less with respect to 100 mole parts of the main component. When the core 1111a contains the secondary component at more than 0.1 mole part with respect to 100 mole parts of the main component, the material properties of a pure dielectric material (e.g., BaTiO 3 ) may change. When the shell 1111b contains the secondary component at 0.1 mole part or less with respect to 100 mole parts of the main component, the variation range of the dielectric constant due to temperature may increase. When it contains more than 30.0 mole parts, the initial insulation resistance may decrease.

[0061] That is, there is no secondary component in the core 1111a, or only a trace amount exists even if it exists. Therefore, the core 1111a consists of only a pure main component without impurities, and the pure main component can generally have a higher dielectric constant than the main component doped with impurity elements. Thereby, the core 1111a can play a role in maintaining the dielectric constant.

[0062] The shell 1111b contains more secondary components than the core 1111a. The secondary component doped at the B-site of the main component (perovskite ABO 3 structure) in the shell 1111b has the effect of increasing the band gap energy at which other rare earths and doping elements diffuse into the dielectric crystal grains 1111. Thereby, it can play a role as a barrier for suppressing the diffusion of other rare earths and doping elements into the dielectric crystal grains 1111. The shell 1111b can play a role in suppressing the growth of the dielectric crystal grains 1111 and contribute to the micronization of the dielectric crystal grains 1111. Also, the secondary component doped at the A-site of the main component in the shell 1111b can play a role in improving the reliability and the dielectric constant.

[0063] The dielectric crystal grains 1111 have a core 1111a of the dielectric crystal grains with an average molar ratio of barium to titanium (Ba / Ti mole ratio) of 0.9975 to 1.0055. As an example, the average molar ratio of barium to titanium (Ba / Ti mole ratio) in the core 1111a of the dielectric crystal grains may be 0.9980 to 1.0050. If the average molar ratio of barium to titanium (Ba / Ti mole ratio) in the core 1111a of the dielectric crystal grains is less than 0.9975 or exceeds 1.0055, the dielectric constant of the capacitor may decrease.

[0064] The components of specific elements (for example, Ba and Ti) in the core 1111a of the dielectric crystal grains can be measured using nano-XRF (nano-X-ray fluorescence), for example, Nano-Synchrotron X-Ray Fluorescence (Nano-SXRF). At this time, the measurement equipment can use ID16A-NI (UPBL04) of the ESRF (European Synchrotron Radiation Facility).

[0065] As an example, after the multilayer capacitor 100 is placed in an epoxy mixture and cured, the side surfaces of the capacitor body 110 in the L-axis direction and the T-axis direction are polished to the 1 / 2 point in the W-axis direction, fixed, and maintained in a vacuum atmosphere chamber to prepare a cross-sectional sample cut from the center of the capacitor body 110 in the W-axis direction in the L-axis direction and the T-axis direction.

[0066] Irradiate a cross-sectional sample of the prepared capacitor body 110 with synchrotron X-rays (10 keV or higher), measure the content of specific elements (for example, Ba and Ti) three times repeatedly in the core 1111a of the dielectric crystal grains, obtain an average value, and use the average value of the minimum and maximum values measured in at least 10 different dielectric crystal grains located in the same dielectric layer as the content of the final specific element. As an example, when selecting at least 10 different dielectric crystal grains located in the same dielectric layer, they can be selected from the scanning electron microscope image obtained by observing the dielectric crystal grains of the dielectric layer 111 located at the center of the active region with a scanning electron microscope (SEM).

[0067] The average area ratio of the shell 1111b included in one dielectric crystal grain 1111 having a core-shell structure to the average area of one dielectric crystal grain 1111 having a core-shell structure may be 30% to 50%, for example 35% to 50%, 35% to 46%, or 38% to 46%. When the average area ratio of the shell 1111b included in one dielectric crystal grain 1111 is less than 30% or exceeds 50%, the dielectric constant of the capacitor may decrease.

[0068] The average area ratio of the shell 1111b included in one dielectric crystal grain 1111 having a core-shell structure can be measured by the following method.

[0069] The surfaces of the capacitor body 110 in the L-axis direction and the T-axis direction (the fifth surface or the sixth surface) are polished in the W-axis direction until the dielectric layer 111 is exposed, for example, to about the halfway point, to expose the cross-sections in the L-axis direction and the T-axis direction. Any dielectric layer 111 is selected in the cross-sections in the L-axis direction and the T-axis direction, and a region with a size of 1 μm × 1 μm (unit area) in the active region is set as the measurement target. Alternatively, the surfaces of the capacitor body 110 in the L-axis direction and the W-axis direction (the first surface or the second surface) are polished in the T-axis direction until the dielectric layer 111 is exposed, for example, to about the halfway point, to expose the dielectric layer 111 in the cross-sections in the L-axis direction and the W-axis direction, and a region with a size of 1 μm × 1 μm (unit area) in the active region can also be set as the measurement target. However, the unit area is set to a region including dielectric crystal grains having at least one core-shell structure.

[0070] For the measurement target, using a transmission electron microscope (TEM), the diameter of one dielectric crystal grain 1111 and the area of one dielectric crystal grain 1111 are measured under the conditions of an acceleration voltage of 200 kV and a WD of 115 mm. At this time, the diameter of one dielectric crystal grain 1111 can be calculated as the average value of the maximum minor axis among the maximum major axis and the minor axis perpendicular thereto, and the area of one dielectric crystal grain 1111 can be calculated using the diameter assuming the dielectric crystal grain 1111 as a circle.

[0071] In addition, for the measurement object, using an EDS (Energy Disperse X-Ray Spectrometer) installed in a transmission electron microscope (TEM, Transmission Electron Microscope), under the conditions of an acceleration voltage of 200 kV, WD of 115 mm, and a mapping scan (dwell time) of 30 μs, measure the composition and elemental distribution of one dielectric crystal grain 1111, and by distinguishing the core 1111a and the shell 1111b, measure the diameter of the core 1111a, the area of the core 1111a, and the area of the shell 1111b. At this time, the diameter of the core 1111a can be calculated as the average value of the major axis and the minor axis perpendicular to it, and the area of the core 1111a can be calculated using the diameter assuming the core 1111a is a circle. Also, the area of the shell 1111b can be calculated by subtracting the area of the core 1111a from the area of the dielectric crystal grain 1111.

[0072] In addition, the average values of the diameter of the measured dielectric crystal grain 1111, the diameter of the core 1111a, the area of the dielectric crystal grain 1111, the area of the core 1111a, and the area of the shell 1111b may be the arithmetic mean of the three values of the dielectric crystal grains 1111 measured in the three different dielectric layers 111 in the cross-sections in the L-axis direction and the T-axis direction obtained above, or may be the arithmetic mean of the total nine values of the dielectric crystal grains 1111 measured at the center, one end, and the other end of the active region in the three different dielectric layers 111 in the cross-sections in the L-axis direction and the T-axis direction.

[0073] The average number of cores 1111a per unit area (1 μm × 1 μm) of the dielectric layer 111 is 25 to 35. As an example, the average number of cores 1111a per unit area (1 μm × 1 μm) of the dielectric layer 111 may be 27 to 35. When the average number of cores 1111a per unit area (1 μm × 1 μm) of the dielectric layer 111 is less than 25 or more than 35, the dielectric constant of the capacitor may decrease.

[0074] FIG. 5 shows the component analysis results within a unit area (1 μm × 1 μm) of the dielectric layer 111 included in a multilayer capacitor according to one embodiment (Example 3), and is an image obtained by performing TEM mapping based on Dy, which is a sub-component. FIG. 6 is an image showing the core 1111a in FIG. 5. Referring to FIG. 6, the number of core 1111a portions having an average diameter of about 50 nm or more within a unit area (1 μm × 1 μm) of the dielectric layer 111 can be measured.

[0075] The average diameter of the dielectric crystal grains 1111 having a core-shell structure may be 100 nm to 1,000 nm, and the average diameter of one core 1111a included in the dielectric crystal grains 1111 having a core-shell structure may be 50 nm to 500 nm.

[0076] As an example, the average thickness of the dielectric layer 111 may be 0.15 μm or more, 0.3 μm or more, 0.5 μm or more, 1.0 μm or more, or 2.0 μm or more, and may be 10 μm or less, 8.0 μm or less, or 5.0 μm or less.

[0077] The average thickness of the dielectric layer 111 can be measured by the following method.

[0078] First, prepare a scanning electron microscope image obtained by observing a cross-sectional sample with a scanning electron microscope (SEM).

[0079] In the scanning electron microscope (SEM) image of the cross-sectional sample, taking the central point in the L-axis direction or the W-axis direction of the dielectric layer 111 as a reference point, the arithmetic mean value of the thicknesses of the dielectric layer 111 at 10 points separated from the reference point by a predetermined interval can be obtained and used as the average thickness of the dielectric layer 111.

[0080] The interval between the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image. For example, the interval may be 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm.

[0081] At this time, all ten points must be located within the dielectric layer 111. If all ten points are not located within the dielectric layer 111, the position of the reference point can be changed, or the interval between the ten points can be adjusted.

[0082] The first internal electrode 121 and the second internal electrode 122 are electrodes having different polarities from each other, and are alternately arranged facing each other along the T-axis direction with the dielectric layer 111 interposed therebetween, and one end is exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0083] The first internal electrode 121 and the second internal electrode 122 are electrically insulated from each other by the dielectric layer 111 disposed in the middle.

[0084] The ends of the first internal electrode 121 and the second internal electrode 122 alternately exposed through the third surface and the fourth surface of the capacitor body 110 are respectively connected to the first external electrode 131 and the second external electrode 132 and can be electrically connected.

[0085] The first internal electrode 121 and the second internal electrode 122 contain a conductive metal, and can contain, for example, a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy thereof, such as an Ag-Pd alloy.

[0086] In addition, the first internal electrode 121 and the second internal electrode 122 can also contain dielectric particles of the same composition system as the ceramic material contained in the dielectric layer 111.

[0087] The first internal electrode 121 and the second internal electrode 122 can be formed using a conductive paste containing a conductive metal. As the printing method of the conductive paste, a screen printing method, a gravure printing method, or the like can be used.

[0088] As an example, the average thickness of the first internal electrode 121 and the second internal electrode 122 may be 0.1 μm to 2 μm.

[0089] The average thickness of the first internal electrode 121 or the second internal electrode 122 may be the arithmetic mean value of the thicknesses of the first internal electrode 121 or the second internal electrode 122 at 10 points separated by a predetermined interval from a reference point with the central point in the length direction (L-axis direction) or the width direction (W-axis direction) of the first internal electrode 121 or the second internal electrode 122 as the reference point in the scanning electron microscope (SEM) image of the cross-sectional sample. The interval between the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image, and may be, for example, an interval of 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm. At this time, all 10 points must be located within the first internal electrode 121 or the second internal electrode 122. If all 10 points are not located within the first internal electrode 121 or the second internal electrode 122, the position of the reference point can be changed, or the interval between the 10 points can be adjusted.

[0090] The first external electrode 131 and the second external electrode 132 are provided with voltages of different polarities, and are respectively connected to the exposed portions of the first internal electrode 121 and the second internal electrode 122 and can be electrically connected.

[0091] With the configuration as described above, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charges are accumulated between the first internal electrode 121 and the second internal electrode 122 facing each other. At this time, the capacitance of the stacked capacitor 100 becomes proportional to the overlapping area of the first internal electrode 121 and the second internal electrode 122 that overlap each other along the T-axis direction in the active region.

[0092] The first external electrode 131 and the second external electrode 132 are respectively disposed on the third surface and the fourth surface of the capacitor body 110, and include a first connection portion and a second connection portion connected to the first internal electrode 121 and the second internal electrode 122, the third surface and the fourth surface of the capacitor body 110, and a first band portion and a second band portion disposed at the corners where the first surface and the second surface or the fifth surface and the sixth surface are in contact.

[0093] The first band portion and the second band portion can each extend from the first connection portion and the second connection portion to a part of the first surface and the second surface or the fifth surface and the sixth surface of the capacitor body 110. The first band portion and the second band portion can serve to improve the adhesion strength of the first external electrode 131 and the second external electrode 132.

[0094] As an example, the first external electrode 131 and the second external electrode 132 can each include a sintered metal layer that contacts the capacitor body 110, a conductive resin layer disposed to cover the sintered metal layer, and a plating layer disposed to cover the conductive resin layer.

[0095] The sintered metal layer can include a conductive metal and glass.

[0096] As an example, the sintered metal layer can include copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), alloys thereof, or combinations thereof as the conductive metal. For example, copper (Cu) can include a copper (Cu) alloy. When the conductive metal includes copper, the metal other than copper may be included in an amount of 5 mol parts or less with respect to 100 mol parts of copper.

[0097] As an example, the sintered metal layer can include a composition in which an oxide is mixed with glass, and may be, for example, 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 is selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal is 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).

[0098] Optionally, the conductive resin layer is formed on the sintered metal layer, for example, it can be formed in a form that completely covers the sintered metal layer. On the other hand, the first external electrode 131 and the second external electrode 132 may not contain the sintered metal layer. In this case, the conductive resin layer can be in direct contact with the capacitor body 110.

[0099] The conductive resin layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110. The length of the region (i.e., the band portion) where the conductive resin layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the band portion) where the sintered metal layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110. That is, the conductive resin layer is formed on the sintered metal layer and can be formed in a form that completely covers the sintered metal layer.

[0100] The conductive resin layer contains resin and conductive metal.

[0101] The resin contained in the conductive resin layer has bonding properties and shock absorption properties, and is not particularly limited as long as it can be mixed with the conductive metal powder to make a paste. For example, it can contain phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0102] The conductive metal contained in the conductive resin layer serves to be electrically connected to the first internal electrode 121 and the second internal electrode 122 or the sintered metal layer.

[0103] The conductive metal contained in the conductive resin layer can have a spherical shape, a flake shape, or a combination of these forms. That is, the conductive metal may consist only of the flake shape, or only of the spherical shape, or may be a form in which the flake shape and the spherical shape are mixed.

[0104] Here, the spherical shape can include forms that are not completely spherical. For example, it can include forms where the length ratio of the major axis to the minor axis (major axis / minor axis) is 1.45 or less. The flake-shaped powder means a powder having a flat and elongated form, and is not particularly limited. For example, the length ratio of the major axis to the minor axis (major axis / minor axis) may be 1.95 or more.

[0105] The first external electrode 131 and the second external electrode 132 can further include a plating layer disposed outside the conductive resin layer.

[0106] The plating layer can include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), etc. alone or alloys thereof. As an example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially laminated, or may be a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer are sequentially laminated. Also, the plating layer can include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0107] The plating layer can improve the mountability with the substrate of the multilayer capacitor 100, the structural reliability, the durability against the outside, the heat resistance, and the equivalent series resistance (ESR).

[0108] The manufacturing method of the multilayer capacitor includes a step of manufacturing dielectric powder, a step of manufacturing a capacitor body including a dielectric layer and an internal electrode, and a step of forming an external electrode outside the capacitor body.

[0109] First, a method for manufacturing dielectric powder will be described.

[0110] While wet-mixing a barium (Ba) precursor and a titanium (Ti) precursor, additional barium (Ba) precursor or titanium (Ti) precursor is added so that the molar ratio of barium to titanium (Ba / Ti mole ratio) becomes 0.9975 to 1.0055.

[0111] This makes it possible to produce barium titanate powder with a uniform molar ratio of barium to titanium. By forming a dielectric layer using this powder, dielectric crystal grains with a uniform molar ratio of barium to titanium can be formed, improving the reliability characteristics.

[0112] The barium (Ba) precursor can be BaO 2 , BaTiO 3 , BaCO 3 , BaO, or combinations thereof.

[0113] The titanium (Ti) precursor may be an oxide, salt, or alkoxide of titanium, etc. For example, it can include titanium dioxide (TiO 2 ), titanium diisopropoxide diacetylacetonate (TPA), titanium alkoxide, or combinations thereof.

[0114] At this time, when the dielectric powder further contains additional elements such as Ca, Sr, Sn, or Zr, precursors of these additional elements can be further added together with the barium (Ba) precursor and the titanium (Ti) precursor. As an example, the precursors of the additional elements may be compounds such as oxides or carbonates containing these additional elements.

[0115] Wet mixing can be carried out, for example, using a disperser such as a bead mill or a ball mill, or by performing high-pressure dispersion treatment to disperse it wet together with a solvent. As an example, when dispersing using a bead mill, beads with a diameter of 0.03 mm to 0.1 mm can be used for dispersion treatment at a peripheral speed of 5 m / s to 15 m / s for 5 passes to 30 passes.

[0116] As the solvent used for wet mixing, for example, an aqueous solvent such as ion-exchanged water, pure water, ultrapure water, or distilled water can be used, or an alcohol-based solvent, ammonia, or an amine-based solvent such as an organic amine can be used together with water.

[0117] Optionally, a dispersant can be further added at the raw material mixing stage, and the dispersant may be, for example, a polyvinyl butyl-based dispersant, a polyvinyl acetal-based dispersant, a polycarboxylic acid-based dispersant, a maleic acid-based dispersant, a polyethylene glycol-based dispersant, an allyl ether copolymer-based dispersant, etc.

[0118] Optionally, the raw material mixture can be dried and dry pulverized.

[0119] Next, the raw material mixture is calcined to produce a dielectric powder.

[0120] The calcination can be carried out at 800°C to 1000°C for 1 hour to 8 hours, or at 840°C to 900°C for 2 hours to 6 hours.

[0121] The calcination can be carried out in a vacuum atmosphere or at normal pressure, for example, in an atmosphere of 10000 Pa to 1000000 Pa. The vacuum atmosphere may be, for example, a vacuum atmosphere of 20000 Pa or less, or 100 Pa or less.

[0122] If the calcination temperature is less than 800°C or the calcination time is less than 1 hour, unreacted and variations may become a problem. If the calcination temperature exceeds 1000°C or the calcination time is less than 1 hour, coarse powders may be synthesized.

[0123] Optionally, after wet pulverizing the dielectric powder, it can be dried and dry pulverized.

[0124] Next, the manufacture of the capacitor body will be described.

[0125] In the manufacturing process of the capacitor body, a dielectric paste that becomes a dielectric layer after firing and a conductive paste that becomes an internal electrode after firing are prepared.

[0126] The dielectric paste is manufactured, for example, by the following method. The manufactured dielectric powder is uniformly mixed by means such as wet mixing, dried, and then heat-treated under predetermined conditions to obtain plastic powder. An organic vehicle or an aqueous vehicle is added to the obtained plastic powder and kneaded to prepare a dielectric paste.

[0127] The obtained dielectric paste is formed into a sheet by a technique such as the doctor blade method to obtain a dielectric green sheet. The dielectric paste may also contain additives selected from various dispersants, plasticizers, dielectrics, sub-component compounds, or glass, etc., if necessary.

[0128] The conductive paste for the internal electrode is prepared by kneading conductive powder made of a conductive metal or its alloy with a binder and a solvent. The conductive paste for the internal electrode may contain ceramic powder (for example, barium titanate powder) as a co-material, if necessary. The co-material can play a role in suppressing the sintering of the conductive powder during the firing process.

[0129] The conductive paste for the internal electrode is applied in a predetermined pattern on the surface of the dielectric green sheet by various printing methods such as screen printing or transfer methods. Then, the dielectric green sheets with the internal electrode patterns formed are laminated over a plurality of layers, and then pressed in the lamination direction to obtain a dielectric green sheet laminate. At this time, on the upper and lower surfaces in the lamination direction of the dielectric green sheet laminate, the dielectric green sheet and the internal electrode pattern can be laminated so that the dielectric green sheet is located.

[0130] Optionally, the obtained dielectric green sheet laminate can be cut into a predetermined size by dicing or the like.

[0131] Further, the dielectric green sheet laminate can be solidified and dried to remove a plasticizer or the like if necessary, and can be barrel polished using a horizontal centrifugal barrel polishing machine or the like after solidification and drying. In barrel polishing, the dielectric green sheet laminate is put into a barrel container together with media and a polishing liquid, and unnecessary portions such as bars generated during cutting can be polished by applying rotational motion, vibration, or the like to the barrel container. Further, after barrel polishing, the dielectric green sheet laminate can be washed with a cleaning liquid such as water and dried.

[0132] The dielectric green sheet laminate is subjected to a debinding process and a firing process to obtain a capacitor body.

[0133] The conditions of the debinding process can be appropriately adjusted according to the main component composition of the dielectric layer and the main component composition of the internal electrode. For example, the heating rate during the debinding process may be 5 °C / hour to 300 °C / hour, the holding temperature may be 180 °C to 400 °C, and the temperature holding time may be 0.5 hour to 24 hours. The debinding atmosphere may be air or a reducing atmosphere.

[0134] The conditions of the firing process can be appropriately adjusted according to the main component composition of the dielectric layer and the main component composition of the internal electrode. For example, the temperature during firing may be 1200 °C to 1350 °C, or 1220 °C to 1300 °C, and the time may be 0.5 hour to 8 hours, or 1 hour to 3 hours. The firing atmosphere may be a reducing atmosphere. For example, it may be an atmosphere in which a mixed gas of nitrogen gas (N 2 ) and hydrogen gas (H 2 ) is humidified. When the internal electrode contains 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.

[0135] After the firing process, annealing can be carried out as necessary. Annealing is a process for re-oxidizing the dielectric layer, and can be carried out when the firing process is carried out in a reducing atmosphere. The conditions of the annealing process can also be appropriately adjusted according to the main component composition of the dielectric layer, etc. For example, the temperature during annealing may be 950°C to 1150°C, the time may be 0 hours to 20 hours, and the heating rate may be 50°C / hour to 500°C / hour. The annealing atmosphere may be a humidified nitrogen gas (N 2 ) atmosphere, and the oxygen partial pressure may be 1.0×10 -9 MPa to 1.0×10 -5 MPa.

[0136] For humidifying nitrogen gas, mixed gas, etc. in the debinding process, firing process, or annealing process, for example, a wetter can be used. In this case, the water temperature may be 5°C to 75°C. The debinding process, firing process, and annealing process can be carried out continuously or independently.

[0137] Optionally, surface treatments such as sandblasting, laser irradiation, or barrel polishing can be carried out on the third and fourth surfaces of the obtained capacitor body. By carrying out such surface treatments, the ends of the first internal electrode and the second internal electrode are exposed on the outermost surfaces of the third and fourth surfaces, whereby the electrical connection between the first external electrode and the second external electrode and the first internal electrode and the second internal electrode becomes good, and an alloy part can be easily formed.

[0138] After applying a paste for forming a sintered metal layer as an external electrode on the outer surface of the obtained capacitor body, it can be sintered to form a sintered metal layer.

[0139] The paste for forming a sintered metal layer can contain a conductive metal and glass. Since the descriptions of the conductive metal and glass are the same as those described above, repeated descriptions are omitted. Further, the paste for forming a sintered metal layer can selectively contain sub-components such as a binder, a solvent, a dispersant, a plasticizer, or oxide powder. For example, as the binder, ethyl cellulose, acrylic, or butyral can be used, and as the solvent, an organic solvent such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, or toluene, or an aqueous solvent can be used.

[0140] As a method for applying the paste for forming a sintered metal layer to the outer surface of the capacitor body, a dipping method, various printing methods such as screen printing, an application method using a dispenser, or a spraying method using a spray can be used. The paste for the sintered metal layer is applied to at least the third and fourth surfaces of the capacitor body, and can also be selectively applied to a part of the first surface, the second surface, the fifth surface, or the sixth surface where the band portions of the first external electrode and the second external electrode are formed.

[0141] Thereafter, the capacitor body coated with the paste for forming a sintered metal layer is dried and sintered at a temperature of 700 °C to 1000 °C for 0.1 hour to 3 hours to form a sintered metal layer.

[0142] Optionally, a conductive resin layer can be formed by applying a paste for forming a conductive resin layer to the outer surface of the obtained capacitor body and then curing it.

[0143] The paste for forming a conductive resin layer can contain a resin and optionally a conductive metal or a non-conductive filler. Since the descriptions of the conductive metal and the resin are the same as those described above, repeated descriptions will be omitted. Further, the paste for forming a conductive resin layer can optionally contain auxiliary components such as a binder, a solvent, a dispersant, a plasticizer, or oxide powder. For example, as the binder, ethyl cellulose, acrylic, or butyral can be used, and as the solvent, an organic solvent such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, or toluene, or an aqueous solvent can be used.

[0144] As an example, the method for forming a conductive resin layer can be to dip the capacitor body 110 into the paste for forming a conductive resin layer and then cure it, or print the paste for forming a conductive resin layer on the surface of the capacitor body 110 by a screen printing method or a gravure printing method, or apply the paste for forming a conductive resin layer on the surface of the capacitor body 110 and then cure it to form.

[0145] Next, a plating layer is formed outside the conductive resin layer.

[0146] As an example, the plating layer can be formed by a plating method, and can also be formed by sputtering or electroplating.

[0147] Hereinafter, specific embodiments of the invention will be presented. However, the embodiments described below are merely for specifically exemplifying or explaining the invention, and the scope of the invention should not be limited thereby.

Example

[0148] (Manufacturing Example) Manufacturing Example 1: Production of Dielectric Powder As the barium (Ba) precursor, BaCO 3 powder, and as the titanium (Ti) precursor, TiO 2Prepare the powder and weigh the prepared powder so that the content ratio is as shown in Table 1 below. Weigh the powder of BaCO 3 and TiO 2 powder into a beaker, add water, and perform wet mixing with a mixer. At this time, while adjusting the ratio of barium (Ba) to titanium (Ti), add the barium (Ba) precursor and titanium (Ti) precursor while dispersing with a bead mill to produce a raw material mixture.

[0149] Dry the produced raw material mixture and perform dry grinding on the agglomerated raw material mixture.

[0150] Calcine the raw material mixture at 950 °C for 3 hours under normal pressure to produce dielectric powder.

[0151] After wet grinding the calcined and agglomerated dielectric powder, dry it and perform dry grinding on the agglomerated raw material mixture to obtain dielectric powder.

[0152]

Table 1

[0153] Manufacturing Example 2: Production of Multilayer Capacitor Use the barium titanate powder produced in Production Example 1 as the main component of the dielectric base material, and use the composition shown in Table 2 below as the sub-component.

[0154] Use zirconium balls (ZrO 2 ball) as the dispersion medium, mix ethanol / toluene with a dispersant and a binder, and then perform mechanical milling to produce a slurry for the dielectric.

[0155] Use the produced slurry for the dielectric and use an on-roll coater with a head ejection method to produce a dielectric green sheet.

[0156] A conductive paste layer containing nickel (Ni) is printed on the surface of a dielectric green sheet, and a dielectric green sheet (width × length × height = 3.2 mm × 2.5 mm × 2.5 mm) with the conductive paste layer formed is laminated and pressed to produce a dielectric green sheet laminate.

[0157] The dielectric green sheet laminate is subjected to a plasticizing process in a nitrogen atmosphere at 400 °C or lower, and then fired at a firing temperature of 1300 °C or lower and a hydrogen concentration of 1.0% H 2 under the following conditions to manufacture multilayer capacitors according to Examples and Comparative Examples.

[0158]

Table 2

[0159] (Experimental Example) Experimental Example 1 The molar ratios of barium (Ba) and titanium (Ti) in the core of the dielectric crystal grains are measured for the multilayer capacitors manufactured in the Examples and Comparative Examples, and the results are shown in Tables 3 and 4.

[0160] Ten multilayer capacitors manufactured in the Examples and Comparative Examples are each prepared. After the multilayer capacitors are put into an epoxy mixture and cured, the sides of the capacitor body 110 in the L-axis direction and the T-axis direction are polished to the 1 / 2 point in the W-axis direction, and after fixation, they are maintained in a vacuum atmosphere chamber to obtain cross-sectional samples of the capacitor body 110.

[0161] For the cross-sectional sample of the obtained capacitor body 110, nano-synchrotron X-ray fluorescence (Nano-SXRF) analysis is performed using ID16A-NI (UPBL04) of the European Synchrotron Radiation Facility (ESRF). At this time, synchrotron X-rays (above 10 keV) are irradiated, and the molar ratios of barium (Ba) and titanium (Ti) in the core of the dielectric crystal grains are measured 3 times repeatedly to calculate the average value.

[0162] Also, the average value of the minimum value and the maximum value measured in 10 different dielectric crystal grains located in the same dielectric layer is used as the final molar ratio of barium (Ba) and titanium (Ti). As an example, FIG. 7 is a scanning electron microscope image obtained by observing the dielectric crystal grains of the dielectric layer included in the capacitor of Example 3 with a scanning electron microscope (SEM). As shown in FIG. 7, at least 10 different dielectric crystal grains located in the same dielectric layer can be selected.

[0163] The molar ratios of barium (Ba) and titanium (Ti) at the 10 points selected in FIG. 7 are shown in Table 3.

[0164] Also, the minimum value (Min.), maximum value (Max.), and average value (Avg.) of the molar ratios of barium (Ba) and titanium (Ti) at the centers of the dielectric crystal grains measured in the examples and comparative examples are tabulated in Table 4.

[0165]

Table 3

[0166] Referring to Table 3, it can be confirmed that the molar ratio of barium to titanium (Ba / Ti mole ratio) of the barium titanate powder in Table 1 used in Example 3 is similar to the molar ratio at the center of the dielectric crystal grains, and the error range is within ±0.0003.

[0167]

Table 4

[0168] Referring to Table 4, it can be seen that for the multilayer capacitors manufactured in the examples, the molar ratio of barium to titanium (Ba / Ti mole ratio) at the center of the dielectric crystallites is 0.9975 to 1.0055.

[0169] Experimental Example 2 The average area ratio of the shells containing the dielectric crystallites having a core-shell structure of the multilayer capacitors manufactured in the examples and comparative examples was measured, and the results are shown in Table 5.

[0170] Ten multilayer capacitors each manufactured in the examples and comparative examples were prepared. The L-axis direction and the T-axis direction surfaces (the fifth surface or the sixth surface) of the capacitor body 110 were polished in the W-axis direction until the dielectric layer 111 was exposed, for example, to about the halfway point, to expose the cross-sections in the L-axis direction and the T-axis direction. An arbitrary dielectric layer 111 was selected from the cross-sections in the L-axis direction and the T-axis direction, and a region with a size of 1 μm × 1 μm (unit area) in the active region was set as the measurement target.

[0171] For the measurement target, Cs STEM (Cs corrected Scanning Transmission Electron Microscope), a type of transmission electron microscope, was used to perform TEM image analysis and EDS mapping component analysis under the condition of an acceleration voltage of 80 kV.

[0172] As an example, FIG. 8 shows the TEM image analysis result for the capacitor of Example 3, and FIG. 5 is an image obtained by performing TEM mapping within a unit area (1 μm × 1 μm) of the dielectric layer 111 for the capacitor of Example 3, with Dy, a minor component, as a reference.

[0173] The area of the dielectric crystal grain shell 1111b is measured through the above TEM image analysis, and the shell area ratio range and the shell average area ratio of three values measured in three different dielectric layers are shown in Table 5 below.

[0174] The number of core 1111a parts with an average diameter of about 50 nm or more within a unit area (1 μm × 1 μm) of the dielectric layer 111 is measured through the above TEM mapping analysis and shown in Table 5 below.

[0175] Also, the dielectric constants of the multilayer capacitors manufactured in the examples and comparative examples are measured, and the results are shown in Table 5.

[0176] Fifty multilayer capacitors manufactured in the examples and comparative examples are each prepared, and measured under the conditions of 1 kHz and 1 V using the E4980A product of Keysight technologies as the LCR meter equipment. The dielectric constant of the MLCC chip is calculated from the dielectric thickness, the internal electrode area, and the number of layers and shown in Table 5 below.

[0177]

Table 5

[0178] Referring to Table 5, in the case of Examples 1 to 8, the average area ratio of the shell is 35% to 50%, and the number of cores per unit area of the dielectric layer is 27 to 35. Therefore, it can be confirmed that the dielectric constant of the capacitor is realized to be 2000 or more.

[0179] Experimental Example 3 The breakdown voltages (BDV) of the multilayer capacitors manufactured in the examples and comparative examples are evaluated, and the results are shown in Table 6.

[0180] Prepare 50 laminated capacitors each manufactured in the examples and comparative examples, and while applying voltage in a sweep manner from 0 V to 1.00000 V up to 1100 V using a Keithley 2410 model measuring instrument, measure the voltage value at the moment when the current value reaches 20 mA as the breakdown voltage value. The breakdown voltage is measured in a silicone oil bath.

[0181] Also, evaluate the high-temperature severe reliability and moisture resistance reliability of the laminated capacitors manufactured in the examples, and show the results in Table 7.

[0182] Prepare 40 laminated capacitors each manufactured in the examples and comparative examples, mount them on a measurement substrate, measure the high-temperature severe reliability (HALT) under the conditions of 150 °C, 150 hours, and 100 V using an ESPEC (PV-222, HALT) facility, and measure the moisture resistance reliability under the conditions of 85 °C, relative humidity (R.H.) 85%, 32 V, and 24 hours using an ESPEC (PR-3J, 8585) facility.

[0183]

Table 6

[0184]

Table 7

[0185] Referring to Table 6 and Table 7 above, in the case of the examples, it can be confirmed that while the dielectric constant is 2000 or more, it has a dielectric loss rate and BDV value at a level similar to that of the comparative examples.

[0186] Also, it can be confirmed that the high-temperature severe reliability (HALT) and moisture resistance reliability of the examples are also at a level similar to that of the comparative examples.

[0187] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made and implemented within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and it is natural that these also belong to the scope of the present invention.

Explanation of Reference Numerals

[0188] 100: Multilayer capacitor 110: Capacitor body 111: Dielectric layer 1111: Dielectric crystal grains having a core-shell structure 1111a: Core of dielectric crystal grains 1111b: Shell of dielectric crystal grains 112, 113: Cover region 121: First internal electrode 122: Second internal electrode 131: First external electrode 132: Second external electrode

Claims

1. a capacitor body including a dielectric layer and an internal electrode; an external electrode disposed on an outer side of the capacitor body; the dielectric layer includes a plurality of dielectric crystal grains containing barium titanate as a main component, At least one of the plurality of dielectric crystal grains has a core-shell structure, The average molar ratio of barium to titanium (Ba / Ti) in the core of the dielectric crystal grain is 0.9975 to 1.0055; A multilayer capacitor, wherein the average number of the cores per unit area (1 μm×1 μm) in the dielectric layer is 25 to 35.

2. 2. The multilayer capacitor according to claim 1, wherein an average molar ratio of barium to titanium (Ba / Ti) in the core of the dielectric crystal grains is 0.9980 to 1.0050.

3. 2. The multilayer capacitor according to claim 1, wherein an average area ratio of the shell contained in one dielectric crystal grain having the core-shell structure to an average area of ​​one dielectric crystal grain having the core-shell structure is 30% to 50%.

4. 4. The multilayer capacitor according to claim 3, wherein an average area ratio of the shell contained in one dielectric crystal grain having the core-shell structure to an average area of ​​one dielectric crystal grain having the core-shell structure is 38% to 46%.

5. The main component is BaTiO ３ , Ba(Ti,Zr)O ３ , Ba(Ti,Sn)O ３ , (Ba,Ca)TiO 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 10. The stacked capacitor of claim 1, comprising:

6. The dielectric crystal grains further include a minor component, 2. The stacked capacitor according to claim 1, wherein the minor component comprises dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), or a combination thereof.

7. 7. The stacked capacitor according to claim 6, further comprising: magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), lanthanum (La), chromium (Cr), hafnium (Hf), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or a combination thereof.

8. The dielectric crystal grains are composed of Dy with respect to 100 parts by mole of the main component. ２ O ３ 0.5 to 1.5 mol parts, MnO ２ 0.05 to 0.15 mol parts, V ２ O ５ 0.05 to 0.15 mol parts, BaCO ３ 1.0 to 2.5 parts by mole, SiO ２ 0.5 to 1.0 mole parts, or Al ２ O ３ 7. The multilayer capacitor according to claim 6, comprising 0.2 to 1.0 mol parts of an auxiliary component.

9. The shell contains more than 0.1 moles and not more than 30.0 moles of all of the subcomponents per 100 moles of the main component, 7. The multilayer capacitor according to claim 6, wherein the core contains 0.1 mol or less of all of the subcomponents per 100 mol of the main component.

10. 2. The multilayer capacitor according to claim 1, wherein the average diameter of the core is from 50 nm to 500 nm.

11. 2. The multilayer capacitor according to claim 1, wherein the average thickness of the dielectric layer is 0.15 μm to 10 μm.

12. a capacitor body including a dielectric layer and an internal electrode; an external electrode disposed on an outer side of the capacitor body; the dielectric layer includes a plurality of dielectric crystal grains containing barium titanate as a main component, At least one of the plurality of dielectric crystal grains has a core-shell structure, The average molar ratio of barium to titanium (Ba / Ti) in the core of the dielectric crystal grain is 0.9975 to 1.0055; the average number of the cores per unit area (1 μm×1 μm) in the dielectric layer is 27 to 35; The multilayer capacitor, wherein the ratio of the average area of ​​the shell contained in one dielectric crystal grain having the core-shell structure to the average area of ​​one dielectric crystal grain having the core-shell structure is 30% to 50%.

13. 13. The multilayer capacitor according to claim 12, wherein an average molar ratio of barium to titanium (Ba / Ti) in the core of the dielectric crystal grains is 0.9980 to 1.0050.

14. 13. The multilayer capacitor according to claim 12, wherein a ratio of an average area of ​​the shell included in one dielectric crystal grain having a core-shell structure to an average area of ​​one dielectric crystal grain having the core-shell structure is 38% to 46%.

15. The main component is BaTiO ３ , Ba(Ti,Zr)O ３ , Ba(Ti,Sn)O ３ , (Ba,Ca)TiO 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 13. The stacked capacitor of claim 12, comprising:

16. The dielectric crystal grains further include a minor component, 13. The stacked capacitor of claim 12, wherein the minor component comprises dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), or a combination thereof.

17. The dielectric crystal grains are composed of Dy with respect to 100 parts by mole of the main component. ２ O ３ 0.5 to 1.5 mol parts, MnO ２ 0.05 to 0.15 mol parts, V ２ O ５ 0.05 to 0.15 mol parts, BaCO ３ 1.0 to 2.5 parts by mole, SiO ２ 0.5 to 1.0 mole parts, or Al ２ O ３ The multilayer capacitor according to claim 16, comprising 0.2 to 1.0 molar parts of an auxiliary component.

18. The shell contains more than 0.1 moles and not more than 30.0 moles of all of the subcomponents per 100 moles of the main component, 17. The multilayer capacitor according to claim 16, wherein the core contains 0.1 moles or less of all of the subcomponents per 100 moles of the main component.

19. 13. The multilayer capacitor according to claim 12, wherein the average diameter of the core is from 50 nm to 500 nm.

20. 13. The multilayer capacitor according to claim 12, wherein the average thickness of the dielectric layer is 0.15 μm to 10 μm.

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