Multilayer capacitor

Abstract

The present disclosure provides a multilayer capacitor, which may include: a capacitor body including a dielectric layer and an inner electrode; and an external electrode disposed on the capacitor body, in which the internal electrode and the dielectric layer may include zirconium (Zr), and in which an average content of zirconium (Zr) with respect to the entire internal electrode may be 0.0005 mol% or more and less than 5.0 mol%.

Description

Technical Field

[0001] The present disclosure relates to a multilayer capacitor. Background Art

[0002] Recently, as electronic devices have rapidly become multifunctional and miniaturized, electronic components have also rapidly miniaturized and the performance of electronic components has been rapidly improved. In addition, there is an increasing need for high reliability of electrical devices used in automobiles, network devices, etc. and industrial electronic components.

[0003] To meet such market demands, competition in the technological development of passive components such as inductors, capacitors, or resistors is accelerating. In particular, much effort is needed to develop various products of multilayer ceramic capacitors (MLCCs) which are passive components and are increasing in use and applications to capture the market.

[0004] In addition, multilayer capacitors are manufactured by stacking dielectric layers and internal electrodes, and are used in various electronic devices such as mobile phones, laptop computers, televisions (TVs) (including liquid crystal displays (LCDs)), etc.

[0005] With recent technological advancements, it is required that multilayer capacitors be miniaturized and have a high capacitance. For this purpose, technologies are being developed to increase the effective electrode area by increasing the connectivity of internal electrodes in contact with the dielectric layer or to microparticleize the dielectric material and the internal electrode material.

[0006] However, when the material is microparticleized, the melting point decreases, which may lower the thermal shrinkage start temperature of the material. In particular, for the metal material included in the internal electrode, the rate of decrease in its thermal shrinkage start temperature is higher than that of the ceramic material included in the dielectric layer, so the difference in thermal shrinkage temperature between the dielectric layer and the internal electrode increases.

[0007] The greater the difference in thermal shrinkage temperature between the dielectric layer and the internal electrode, the greater the possibility that the electrode connectivity will deteriorate after firing the dielectric layer and the internal electrode, and the capacitance and reliability of the multilayer capacitor may deteriorate.

[0008] Currently, in order to reduce the difference in thermal shrinkage temperature between the dielectric layer and the internal electrode, a method of using a co-material of adding nanosized barium titanate (BaTiO3) is used when manufacturing the internal electrode.

[0009] However, when the content of barium titanate vacancies increases, the film density of the internal electrode decreases, and the co-material diffused into the dielectric layer during the firing process increases the thickness of the dielectric layer, resulting in a side effect of reducing the capacitance of the capacitor. Therefore, it is necessary to develop a new co-material with high thermal stability. Summary of the Invention

[0010] The present disclosure provides a multilayer capacitor having improved electrode connectivity and excellent electrical characteristics and reliability.

[0011] However, the problems to be solved by the present disclosure are not limited to the above problems, and various extensions can be made within the scope of the technical idea included in the embodiments.

[0012] A multilayer capacitor may include: a capacitor body including a dielectric layer and an internal electrode; and an external electrode provided on the capacitor body, wherein the internal electrode and the dielectric layer may include zirconium (Zr), and wherein the average content of zirconium (Zr) in the internal electrode relative to all components of the internal electrode may be greater than or equal to 0.0005 mol% and less than 5.0 mol%.

[0013] The internal electrode may further include a conductive metal other than zirconium (Zr).

[0014] The dielectric layer may include a main component and a sub-component, and the main component may include (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3 (0.995 ≤ m ≤ 1.010, x ≤ 0.10) or a combination thereof.

[0015] The average content of zirconium (Zr) in the internal electrode relative to all components of the internal electrode may be 0.001 mol% to 1.0 mol%.

[0016] The dielectric layer may include a central portion and an interface portion in the thickness direction, the interface portion being located on two surfaces of the central portion of the dielectric layer and contacting the internal electrode, the average content of zirconium (Zr) in the interface portion of the dielectric layer relative to all components of the interface portion of the dielectric layer may be 0.001 mol% to 10.0 mol%, and the average content of zirconium (Zr) in the central portion of the dielectric layer relative to all components of the central portion of the dielectric layer may be 0 mol% to 2.0 mol%.

[0017] The dielectric layer may include a plurality of dielectric grains, the plurality of dielectric grains may include first dielectric grains located in the interface portion of the dielectric layer and second dielectric grains located in the central portion of the dielectric layer, and the average particle size of the first dielectric grains may be smaller than the average particle size of the second dielectric grains.

[0018] The average particle size of the first dielectric grains may be from 50 nm to 200 nm, and the average particle size of the second dielectric grains may be from 150 nm to 500 nm.

[0019] The average thickness of the dielectric layer may be from 0.1 µm to 5 µm.

[0020] The average thickness of the internal electrode may be from 0.1 µm to 2 µm.

[0021] A multilayer capacitor may include: a capacitor body including a dielectric layer and an internal electrode; and an external electrode disposed on the capacitor body, wherein the internal electrode may include zirconium (Zr) and a conductive metal other than zirconium (Zr), and wherein the dielectric layer may include (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3 (0.995 ≤ m ≤ 1.010, x ≤ 0.10) or a combination thereof, and wherein the average content of zirconium (Zr) in the internal electrode relative to all components of the internal electrode may be greater than or equal to 0.0005 mol% and less than 5.0 mol%.

[0022] The average content of zirconium (Zr) in the internal electrode relative to all components of the internal electrode may be from 0.001 mol% to 1.0 mol%.

[0023] The dielectric layer may include a central portion and an interface portion in the thickness direction, the interface portion being located on two surfaces of the central portion of the dielectric layer and in contact with the internal electrode, the average content of zirconium (Zr) in the interface portion relative to all components of the interface portion of the dielectric layer may be from 0.001 mol% to 10.0 mol%, and the average content of zirconium (Zr) in the central portion relative to all components of the central portion of the dielectric layer may be from 0 mol% to 2.0 mol%.

[0024] The dielectric layer may include a plurality of dielectric grains, the plurality of dielectric grains may include first dielectric grains located in the interface portion of the dielectric layer and second dielectric grains located in the central portion of the dielectric layer, and the average particle size of the first dielectric grains may be smaller than the average particle size of the second dielectric grains.

[0025] The average particle size of the first dielectric grains may be from 50 nm to 200 nm, and the average particle size of the second dielectric grains may be from 150 nm to 500 nm.

[0026] The average thickness of the dielectric layer may be from 0.1 µm to 5 µm.

[0027] The average thickness of the internal electrode may be from 0.1 µm to 2 µm.

[0028] The multilayer capacitor according to the embodiment may have improved electrode connectivity and excellent electrical characteristics and reliability.

[0029] Various beneficial advantages and effects of the present disclosure are not limited to the above description and will be more easily understood during the process of describing specific embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view showing a multilayer capacitor according to an embodiment.

[0031] Figure 2 is Figure 1 a cross-sectional view of the multilayer capacitor taken along line I-I'.

[0032] Figure 3 is showing Figure 1 an exploded perspective view of the capacitor body.

[0033] Figure 4 is a transmission electron microscope (TEM) image of a part of a cross-section of a multilayer capacitor according to an embodiment.

[0034] Figure 5 and Figure 6 are graphs showing the results of line analysis of Ti content, Ni content, and Zr content by transmission electron microscope-energy dispersive X-ray spectrometer (TEM-EDS) according to the positions of the dielectric layer and the internal electrode.

[0035] Figure 7 is a schematic diagram showing a part of a cross-section of a multilayer capacitor according to an embodiment.

[0036] Figure 8 is a graph showing the thermal shrinkage rate (%) according to temperature of the conductive paste prepared in Reference Example 1 to Reference Example 4.

[0037] <Description of Symbols> 100: Multilayer capacitor 110: Capacitor body 111: Dielectric layer 1111: Dielectric grains 1111a: First dielectric grains 1111b: Second dielectric grains 112, 113: Covering region 121: First internal electrode 122: Second inner electrode 131: First outer electrode 132: Second outer electrode. Detailed implementation manners

[0038] Hereinafter, embodiments of the present disclosure will be described more fully with reference to the accompanying drawings showing embodiments of the present disclosure. The accompanying drawings and the description are considered to be illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals represent the same elements. In addition, the accompanying drawings are provided only to allow an easy understanding of the embodiments disclosed in this specification and should not be construed as limiting the spirit disclosed in this specification, and it should be understood that the present disclosure includes all modifications, equivalents, and alternatives that do not depart from the scope and spirit of the present disclosure.

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

[0040] When it is mentioned that a certain component is "combined" or "connected" with another component, it can be understood that although the component can be directly combined or directly connected with another component, there may be another component between the two components. In addition, when it is mentioned that a certain component is "directly combined" or "directly connected" with another component, it must be understood that there is no other component between the two components.

[0041] Throughout the specification, the terms "comprising" or "having" are intended to enumerate the presence of the stated features, quantities, steps, operations, components, parts, or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, steps, operations, components, parts, and / or their combinations. Therefore, unless explicitly described to the contrary, the words "comprising" and variations such as "including" or "containing" will be understood to imply the inclusion of the stated elements without excluding any other elements.

[0042] Figure 1 is a perspective view showing a multilayer capacitor 100 according to an embodiment. Figure 2 is along Figure 1 a sectional view of the multilayer capacitor 100 taken along line I-I'. Figure 3 is a perspective exploded view showing Figure 1 the capacitor body 110 of

[0043] When defining directions to clearly describe the present embodiment, the L-axis direction, the W-axis direction, and the T-axis direction shown in the drawings respectively represent the length direction, the width direction, and the thickness direction of the capacitor body 110. Here, the thickness direction (T-axis direction) may be a direction perpendicular to the wide surface (main surface) of the sheet-like component. For example, it may be used with the same concept as the stacking direction of the stacked dielectric layers 111. The length direction (L-axis direction) may be a direction extending parallel to the wide surface (main surface) of the sheet-like component and substantially perpendicular to the thickness direction (T-axis direction). For example, it may be the direction in which the first external electrode 131 and the second external electrode 132 face each other. The width direction (W-axis direction) may be a direction extending parallel to the wide surface (main surface) of the sheet-like component and substantially perpendicular to the thickness direction (T-axis direction), and the length of the sheet-like component in the length direction (L-axis direction) may be longer than the length in the width direction (W-axis direction).

[0044] Referring to Figures 1 to 3 , the multilayer capacitor 100 according to an embodiment may include a capacitor body 110 and external electrodes 131 and 132 provided on the capacitor body 110. The external electrodes 131 and 132 include a first external electrode 131 and a second external electrode 132 provided at opposite ends of the capacitor body 110 in the length direction (L-axis direction).

[0045] The capacitor body 110 may have, for example, a generally hexahedral shape.

[0046] In the present embodiment, for ease of explanation, in the capacitor body 110, the surfaces facing each other in the thickness direction (T-axis direction) are defined as a first surface and a second surface, the surfaces connected to the first surface and the second surface and facing each other in the length direction (L-axis direction) are defined as a third surface and a fourth surface, and the surfaces connected to the first surface and the second surface, connected to the third surface and the fourth surface, and facing each other in the width direction (W-axis direction) are defined as a fifth surface and a sixth surface.

[0047] For example, the first surface as the lower surface may be the mounting surface. In addition, 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 curved surfaces having convex central portions, and the edges serving as boundaries of each surface may be rounded.

[0048] 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 embodiment for the capacitor body 110 and the stacked dielectric layers 111.

[0049] The capacitor body 110 may be formed by stacking a plurality of dielectric layers 111 in the thickness direction (T-axis direction) and then firing them, and may include a plurality of dielectric layers 111, a plurality of first internal electrodes 121, and a plurality of second internal electrodes 122. The first internal electrodes 121 and the second internal electrodes 122 are alternately arranged in the thickness direction (T-axis direction), and the dielectric layer 111 is interposed between the first internal electrode 121 and the second internal electrode 122.

[0050] Here, each of the adjacent dielectric layers 111 of the capacitor body 110 may be integrated to such an extent that it is difficult to identify the boundary between them without using a scanning electron microscope (SEM).

[0051] In addition, the capacitor body 110 may include an effective region, and covering regions 112 and 113.

[0052] The effective region contributes to generating the capacitance of the multilayer capacitor 100. For example, the effective region may be a region where the first internal electrodes 121 and the second internal electrodes 122 are stacked and overlapped with each other along the thickness direction (T-axis direction).

[0053] The covering regions 112 and 113 may be provided as edge portions in the thickness direction on the upper surface and the lower surface of the effective region that are opposite to each other in the thickness direction (T-axis direction). The covering regions 112 and 113 may be formed by stacking a single dielectric layer 111 or two or more dielectric layers 111 on the upper surface and the lower surface of the effective region, respectively.

[0054] In addition, the capacitor body 110 may further include side covering regions. The side covering regions are edge portions and may be provided on two side surfaces of the effective region that are opposite to each other in the width direction (W-axis direction). Such side covering regions may be formed by: coating a conductive paste for forming an internal electrode only on a part of the surface of the dielectric green sheet except for the part where the side covering regions are to be formed, and then obtaining the side covering regions through stacking, cutting, and sintering operations. Or, such side covering regions may be formed by: coating a conductive paste for an internal electrode on the entire surface of the dielectric green sheet, obtaining a dielectric green sheet stack through stacking and cutting, and then stacking dielectric green sheets that are not coated with the conductive paste on two side surfaces of the dielectric green sheet stack and firing them.

[0055] The covering regions 112 and 113 and the side covering regions are used to prevent damage to the first internal electrodes 121 and the second internal electrodes 122 due to physical stress and / or chemical stress.

[0056] Inner electrode The first inner electrode 121 and the second inner electrode 122 are electrodes with different polarities, and are alternately arranged to face each other along the thickness direction, and a dielectric layer 111 is interposed between the first inner electrode 121 and the second inner electrode 122, and one end of the first inner electrode 121 and one end of the second inner electrode 122 can be exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0057] The first inner electrode 121 and the second inner electrode 122 can be electrically insulated from each other by the dielectric layer 111 provided therebetween.

[0058] The ends of the first inner electrode 121 and the second inner electrode 122 alternately exposed through the third surface and the fourth surface of the capacitor body 110 are respectively connected to the first outer electrode 131 and the second outer electrode 132 for electrical connection.

[0059] The inner electrodes 121 and 122 may include zirconium (Zr), and as an example, may include zirconium (Zr) and a conductive metal other than zirconium (Zr), and may include an alloy of zirconium (Zr) and a conductive metal other than zirconium (Zr). It should be understood that if not otherwise specified, the inner electrode including zirconium (Zr) means that the inner electrode includes zirconium (Zr) element, wherein the zirconium (Zr) element may exist in the form of a simple substance, a compound (for example, an oxide or an alloy with other conductive metals).

[0060] Zirconium (Zr) may be added to the conductive paste for the inner electrode in the form of an oxide of Zr (ZrO2), and after the firing process, the inner electrodes 121 and 122 may include an oxide of Zr (ZrO2), elemental Zr, an alloy of Zr and other conductive metals, or a combination thereof.

[0061] Since the oxide of Zr (ZrO2) has a melting point about 1100 °C higher than the melting point of barium titanate (BaTiO3) (a commonly used co-material), compared with the case of using barium titanate, when the conductive paste for the inner electrode includes an oxide of Zr and is fired, the delaying effect of the thermal shrinkage of the inner electrode is super excellent. Therefore, the thermal stability of the inner electrode is increased, and the electrode connectivity of the inner electrode can be significantly improved.

[0062] According to some embodiments, the conductive metal other than zirconium (Zr) described above may include metals such as Ni, Cu, Ag, Pd, or Au or their alloys (for example, Ag-Pd alloy). For example, when the conductive metal other than zirconium (Zr) described above includes Ni, the first inner electrode 121 and the second inner electrode 122 may include Ni and Zr, for example, a Ni-Zr alloy.

[0063] In addition, the first internal electrode 121 and the second internal electrode 122 may include dielectric particles having the same composition as the ceramic material included in the dielectric layer 111.

[0064] The first internal electrode 121 and the second internal electrode 122 may be formed using a conductive paste containing a conductive metal. A screen printing method, a gravure printing method, or the like may be used as a method for printing the conductive paste.

[0065] According to some embodiments, the average content of zirconium (Zr) in the internal electrodes 121 and 122 is greater than or equal to 0.0005 mol% and less than 5.0 mol% with respect to all components of the internal electrodes 121 and 122.

[0066] According to some embodiments, the average content of zirconium (Zr) in the internal electrodes 121 and 122 may be greater than or equal to 0.001 mol%, and may be less than 2.5 mol% or less than 1.0 mol%.

[0067] According to some embodiments, the average content of zirconium (Zr) in the internal electrodes 121 and 122 may be 0.0005 mol% to 2.5 mol%, for example, may be 0.001 mol% to 2.5 mol% or 0.001 mol% to 1.0 mol%.

[0068] When the average content of zirconium (Zr) in the internal electrodes 121 and 122 is less than 0.0005 mol% with respect to all components of the internal electrodes 121 and 122, the effect of improving electrode connectivity may be insufficient, and when the average content of zirconium (Zr) in the internal electrodes 121 and 122 is greater than or equal to 5 mol% with respect to all components of the internal electrodes 121 and 122, the electrical characteristics and reliability of the capacitor may deteriorate.

[0069] Figure 4 is a TEM image of a part of a cross-section of a multilayer capacitor according to an embodiment.

[0070] Figure 5 and Figure 6 is a graph showing the results of line analysis of the Ti content, Ni content, and Zr content by TEM-EDS according to the position of the dielectric layer and the position of the internal electrode.

[0071] Refer to Figures 4 to 6 , the average content (mol%) of zirconium (Zr) in the internal electrodes 121 and 122 can be measured by the following method.

[0072] First, after placing the multilayer capacitor 100 in the epoxy resin mixture and then curing it, the side surfaces of the multilayer capacitor 100 in the W-axis direction and the T-axis direction are polished to a point that is 1 / 2 of the capacitor body 110 in the L-axis direction, and it is fixed and held in a vacuum atmosphere chamber, thereby preparing a cross-sectional sample (hereinafter referred to as "cross-sectional sample") of the multilayer capacitor 100 that is cut in the W-axis direction and the T-axis direction at the center of the capacitor body 110 in the L-axis direction.

[0073] Then, by observing the cross-sectional sample with a transmission electron microscope (TEM), a TEM image as Figure 4 shown is obtained.

[0074] Subsequently, by mapping the TEM image of the cross-sectional sample to the Zr component, it can be confirmed whether Zr is detected from the cross-sectional sample, and if Zr is detected, the position of the Zr distribution can also be confirmed.

[0075] Then, by performing line scan analysis using an energy dispersive X-ray spectrometer (EDS) installed in a transmission electron microscope (TEM), the Zr content according to the distribution position can be measured.

[0076] Referring to Figure 5 and Figure 6 , the Zr present in the inner electrode and its content can be confirmed, and by performing line scan analysis at at least two points and obtaining the arithmetic mean, the average Zr content included in the inner electrode can be obtained.

[0077] According to some embodiments, the average thickness of the first inner electrode 121 and / or the second inner electrode 122 may be 0.1 µm or greater, 0.2 µm or greater, or 0.25 µm or greater, and may be 2.0 µm or less, 1 µm or less, or 0.5 µm or less.

[0078] The average thickness of the inner electrodes 121 and 122 can be measured by the following method.

[0079] In the scanning electron microscope (SEM) image of the cross-sectional sample, the average thickness of the inner electrode can be obtained by taking the arithmetic mean of the thicknesses at 10 points of the first inner electrode 121 and / or the second inner electrode 122 that are spaced apart from a reference point at a predetermined interval, and the reference point is the center point of the first inner electrode 121 and / or the second inner electrode 122 in the W-axis direction.

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

[0081] Here, all 10 points must be located entirely within the first internal electrode 121 and / or the second internal electrode 122. However, when all 10 points cannot be located entirely within the first internal electrode 121 and / or the second internal electrode 122, the reference points can be repositioned, or the intervals between the 10 points can be adjusted.

[0082] Dielectric layer Through the firing process, the oxide of zirconium (ZrO2) added to the conductive paste for the internal electrodes can partially diffuse into the dielectric layer 111 in the form of Zr, and the diffused Zr can be mainly distributed near the interfaces of the dielectric layer 111 adjacent to the internal electrodes 121 and 122.

[0083] The Zr diffused near the interfaces of the dielectric layer 111 can inhibit the grain growth of the dielectric grains located near the interfaces. Thus, due to the reduction in the size of the dielectric grains, the interface reliability between the dielectric layer 111 and the internal electrodes 121 and 122 can be increased.

[0084] In addition, by increasing the average grain size of the dielectric grains included in the central portion of the dielectric layer 111, a multilayer capacitor with excellent electrical characteristics and reliability can be achieved.

[0085] Figure 7 is a schematic diagram showing a part of the cross-section of the multilayer capacitor 100 according to an embodiment.

[0086] Referring to Figure 7 , the dielectric layer 111 may include a plurality of dielectric grains 1111.

[0087] The dielectric grains 1111 may include a main component and a sub-component.

[0088] The main component may be a dielectric matrix material, having a high dielectric constant and contributing to the formation of the capacitance of the multilayer capacitor 100.

[0089] The main component may include Ba m TiO3 (0.995 ≤ m ≤ 1.010), (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3 (0.995 ≤ m ≤ 1.010, 0 < x ≤ 0.10), (Ba 1- x Ca x ) m (Ti 1-ySn y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), or a dielectric material of a combination thereof.

[0090] According to some embodiments, the main component may include (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3 (0.995 ≤ m ≤ 1.010, x ≤ 0.10), or a combination thereof.

[0091] According to some embodiments, the main component may include at least one selected from the group consisting of BaTiO3, Ba(Ti, Zr)O3, Ba(Ti, Sn)O3, (Ba,Ca)TiO3, (Ba, Ca)(Ti, Zr)O3, (Ba, Ca)(Ti, Sn)O3, (Ba, Sr)TiO3, (Ba, Sr)(Ti, Zr)O3, and (Ba, Sr)(Ti, Sn)O3.

[0092] The sub-component may include at least one selected from the group consisting of zirconium (Zr), manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), hafnium (Hf), germanium (Ge), gallium (Ga), indium (In), lanthanum (La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0093] The dielectric layer 111 may further include a ceramic additive, an organic solvent, a binder, a dispersant, or a combination thereof.

[0094] Referring to Figure 7 , the dielectric layer 111 may include a central portion and an interface portion, and the interface portion is located on the surface of the central portion and contacts the inner electrodes 121 and 122.

[0095] The central portion of the dielectric layer 111 can be represented as: in a cross-section taken in the W-axis direction and the T-axis direction at the center of the capacitor body 110 in the L-axis direction, in the T-axis direction, the central point between a point on one side surface of the dielectric layer 111 and a point on the other side surface of the dielectric layer 111 located at the shortest distance from the one point. In addition, in addition to the central point, the central portion of the dielectric layer 111 can also represent a region within ±30% of the thickness of the dielectric layer 111 in the T-axis direction based on the central point.

[0096] The interface portion of the dielectric layer 111 is the region of the dielectric layer 111 other than the central portion, and can be represented as a point spaced 100 nm from the interface provided between the dielectric layer 111 and the inner electrodes 121 and 122 in the T-axis direction toward the central portion of the dielectric layer 111. In addition, in addition to this point, the interface portion of the dielectric layer can also represent a region within ±30% of the thickness of the dielectric layer 111 in the T-axis direction based on this point.

[0097] Referring to Figure 5 and Figure 6 , the interface portion of the dielectric layer 111 includes a relatively large amount of Zr diffused from the inner electrode, and the Zr content can decrease toward the central portion of the dielectric layer 111.

[0098] In an embodiment, the average content of zirconium (Zr) in the interface portion of the dielectric layer 111 relative to all components of the interface portion of the dielectric layer 111 can be 0.001 mol% to 10.0 mol%, for example, it can be 0.01 mol% to 10.0 mol%, 0.1 mol% to 10.0 mol%, or 0.1 mol% to 5.0 mol%.

[0099] When the average content of zirconium (Zr) in the interface portion of the dielectric layer 111 relative to all components of the interface portion of the dielectric layer 111 satisfies the above numerical range, a multilayer capacitor with improved interface reliability can be achieved.

[0100] According to some embodiments, the average content of zirconium (Zr) in the central portion of the dielectric layer 111 relative to all components of the central portion of the dielectric layer 111 can be 0 mol% to 2.0 mol%, for example, it can be 0 mol% to 1.0 mol% or 0 mol% to 0.5 mol%.

[0101] When the average content of zirconium (Zr) in the central portion of the dielectric layer 111 relative to all components of the central portion of the dielectric layer 111 satisfies the above numerical range, a multilayer capacitor with excellent electrical characteristics and reliability can be achieved.

[0102] The average content of zirconium (Zr) in the interface portion of the dielectric layer 111 and the central portion of the dielectric layer 111 can be measured by the following method.

[0103] Select any five or more dielectric layers 111 in the TEM image of the cross-sectional sample, and select five equally spaced points corresponding to the central portion of the dielectric layer 111 and five equally spaced points corresponding to the interface portion of the dielectric layer 111. Point quantitative analysis (such as, such as Figure 5 and Figure 6 ) can be performed at each selected point to measure the content of Zr, and the arithmetic mean of the measured values can be calculated so that the average content of zirconium (Zr) in the interface portion and the central portion of the dielectric layer 111 can be obtained.

[0104] Referring to Figure 7 , the dielectric grains 1111 may include first dielectric grains 1111a located in the interface portion of the dielectric layer 111 and second dielectric grains 1111b located in the central portion of the dielectric layer 111.

[0105] According to some embodiments, the average particle size of the first dielectric grains may be smaller than the average particle size of the second dielectric grains.

[0106] According to some embodiments, the average particle size of the first dielectric grains 1111a may be 50 nm to 200 nm, and may be, for example, 50 nm to 150 nm or 50 nm to 100 nm.

[0107] According to some embodiments, the average particle size of the second dielectric grains 1111b may be 150 nm to 500 nm, and may be, for example, 200 nm to 500 nm or 200 nm to 400 nm.

[0108] The average particle sizes of the first dielectric grains 1111a and the second dielectric grains 1111b can be measured as follows.

[0109] First, by using a method such as binarizing the TEM image or SEM image of the cross-sectional sample, the boundaries (grain boundaries) of the dielectric grains can be identified by distinguishing regions with contrast differences, and the shapes of the first dielectric grains 1111a and the second dielectric grains 1111b can be identified.

[0110] Select five equally spaced points corresponding to the central portion of the dielectric layer 111 and five equally spaced points corresponding to the interface portion of the dielectric layer 111 from the TEM image or SEM image, and select three or more dielectric grains observed at the selected points to measure their particle sizes and calculate the arithmetic mean, so that the average particle sizes of the first dielectric grains 1111a and the second dielectric grains 1111b can be measured.

[0111] According to some embodiments, the average thickness of the dielectric layer 111 may be 0.1 µm or greater, 0.5 µm or greater, or 1.0 µm or greater, and may be 5.0 µm or less or 2.5 µm or less.

[0112] The average thickness of the dielectric layer 111 can be measured as follows.

[0113] First, a scanning electron microscope (SEM) image is obtained by observing a cross-sectional sample with a scanning electron microscope.

[0114] In the scanning electron microscope (SEM) image of the cross-sectional sample, the average thickness of the dielectric layer 111 can be obtained by: taking the center point of the dielectric layer 111 in the W-axis direction as a reference point, measuring the thickness of the dielectric layer 111 at 10 points spaced at a predetermined interval from the reference point, and calculating the arithmetic mean thereof.

[0115] The predetermined interval of the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image. For example, it can be 1 µm to 100 µm, 1 µm to 50 µm, or 1 µm to 10 µm. Here, the interval can refer to the interval between two adjacent points.

[0116] Here, all 10 points must be located within the dielectric layer 111. However, when not all 10 points are located within the dielectric layer 111, the reference point can be repositioned, or the interval of the 10 points can be adjusted.

[0117] Outer electrode The first external electrode 131 and the second external electrode 132 are supplied with voltages of different polarities and are electrically connected to the exposed portions of the first internal electrode 121 and the second internal electrode 122, respectively.

[0118] According to the above configuration, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charges accumulate between the first internal electrode 121 and the second internal electrode 122. At this time, the capacitance of the multilayer capacitor 100 is proportional to the overlapping area where the first internal electrode 121 and the second internal electrode 122 overlap each other along the T-axis direction in the effective region.

[0119] The first outer electrode 131 may include a first connection portion arranged on the third surface of the capacitor body 110 and connected to the first inner electrode 121, and may also include a first band portion arranged at each corner where the third surface of the capacitor body 110 intersects with the first and second surfaces and / or the fifth and sixth surfaces 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 and connected to the second inner electrode 122, and may also include a second band portion arranged at each corner where the fourth surface of the capacitor body 110 intersects with the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110.

[0120] The first band portion may also extend from the first connection portion to a portion of the first surface and a portion of the second surface and / or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110, and the second band portion may also extend from the second connection portion to a portion of the first surface and a portion of the second surface and / or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110. The first band portion and the second band portion may be used to improve the bonding strength of the first external electrode 131 and the second external electrode 132 to the capacitor body 110, respectively.

[0121] For example, the first and second external electrodes 131 and 132 respectively include a sintered metal layer contacting the capacitor body 110 , a conductive resin layer configured to cover the sintered metal layer, and a plated layer configured to cover the conductive resin layer.

[0122] The sintered metal layer may include conductive metal and glass.

[0123] For example, the sintered metal layer may include at least one selected from the group consisting of copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb) and alloys thereof as a single substance as a conductive metal. For example, the sintered metal layer may include copper (Cu) single substance and / or copper (Cu) alloy. When the conductive metal includes copper, a metal other than copper may be included in an amount of less than or equal to 5 mol parts based on 100 mol parts of copper.

[0124] According to some embodiments, the sintered metal layer may further include glass. In this case, the sintered metal layer may include a composition mixed with oxides as the glass. For example, the glass may include at least one 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 at least one selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni). The alkali metal may be at least one selected from the group consisting of lithium (Li), sodium (Na), and potassium (K). And the alkaline earth metal may be at least one selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0125] Optionally, a conductive resin layer is formed on the sintered metal layer. For example, the conductive resin layer may be formed to completely cover the sintered metal layer. Additionally, the first external electrode 131 and the second external electrode 132 may not include the sintered metal layer. And in this case, the conductive resin layer may be in direct contact with the capacitor body 110.

[0126] The conductive resin layer may extend to the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110. And the length of the region (i.e., the strip portion) where the conductive resin layer extends to the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110 may be longer than the length of the region (i.e., the strip portion) where the sintered metal layer extends to the first surface and the second surface and / or the fifth surface and the sixth surface of the capacitor body 110. That is to say, the conductive resin layer may be formed on the sintered metal layer and completely cover the sintered metal layer.

[0127] The conductive resin layer may include a resin and a conductive metal.

[0128] The resin included in the conductive resin layer is not particularly limited as long as it has adhesiveness and shock absorbency and can be mixed with the conductive metal powder to form a paste. For example, the resin included in the conductive resin layer may include a phenolic resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

[0129] The conductive metal included in the conductive resin layer can be used for electrical connection to the first internal electrode 121 and the second internal electrode 122 or the sintered metal layer.

[0130] The conductive metal included in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof. That is to say, the conductive metal may be formed only in a flake shape, or may be formed only in a spherical shape, or may have a mixed shape of a flake shape and a spherical shape.

[0131] Here, the spherical shape may also include shapes that are not perfect spheres, and may include, for example, shapes in which the length ratio between the major axis and the minor axis (major axis / minor axis) is less than or equal to 1.45. The sheet-like shape represents a flat and elongated shape, and is not particularly limited. For example, the length ratio between the major axis and the minor axis (major axis / minor axis) may be greater than or equal to 1.95.

[0132] The first outer electrode 131 and the second outer electrode 132 may also include a plating layer located outside the conductive resin layer.

[0133] The plating layer may include at least one selected from the group consisting of nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), and their alloys as single elements. For example, the plating layer may include a nickel (Ni) plating layer or a tin (Sn) plating layer, or may have a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are stacked in sequence, or a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer may be stacked in sequence. In addition, the plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0134] The plating layer can improve the mountability of the multilayer capacitor 100 to the board, structural reliability, external durability, heat resistance, and equivalent series resistance (ESR).

[0135] Manufacturing method of multilayer capacitor A method of manufacturing a multilayer capacitor according to another embodiment may include: manufacturing a capacitor body including a dielectric layer and an inner electrode; and forming an outer electrode on the outside of the capacitor body.

[0136] First, the manufacturing of the capacitor body will be described.

[0137] 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 inner electrode after firing are prepared.

[0138] For example, the dielectric paste is prepared by the following method. The dielectric powder is uniformly mixed by means such as wet mixing, dried, and then heat-treated under predetermined conditions to obtain a calcined powder. An organic carrier or an aqueous carrier is added to the obtained calcined powder and kneaded to prepare the dielectric paste.

[0139] The obtained dielectric paste is formed into a sheet using a technique such as a doctor blade method to obtain a green sheet of the dielectric. In addition, if necessary, the dielectric paste may contain additives selected from various dispersants, plasticizers, binders, sub-component compounds, and glass.

[0140] A conductive paste for an internal electrode is prepared by kneading conductive powder made of a conductive metal or its alloy with a binder or a solvent. According to some embodiments, a conductive paste for an internal electrode can be prepared by kneading zirconium oxide. If necessary, the conductive paste for an internal electrode can include ceramic powder (e.g., barium titanate powder) as a co-material (i.e., the same material as the material of the dielectric layer). The co-material can be used to inhibit the sintering of the conductive powder during the firing process.

[0141] On the surface of the dielectric green sheet, the conductive paste for the internal electrode is coated in a predetermined pattern by various printing methods such as screen printing or a transfer method. After stacking multiple dielectric green sheets on which internal electrode patterns are formed, a dielectric green sheet laminate is obtained by pressing in the stacking direction. At this time, dielectric green sheets without internal electrode patterns can be stacked such that the dielectric green sheets can be disposed on the upper surface and the lower surface of the dielectric green sheet laminate in the stacking direction.

[0142] Optionally, the obtained dielectric green sheet laminate can be cut into a predetermined size by cutting or the like.

[0143] In addition, the dielectric green sheet laminate can be cured and dried to remove a plasticizer or the like, and after curing-drying, barrel polishing is performed by using a centrifugal barrel machine or the like. During barrel polishing, the dielectric green sheet laminate, a medium, and a polishing liquid are placed in a barrel container, and then a rotational motion or vibration is applied to the barrel container to polish unnecessary parts (such as burrs generated during cutting). In addition, after barrel polishing, the dielectric green sheet laminate is cleaned with a cleaning solution (such as water) and dried.

[0144] The dielectric green sheet laminate is processed to remove the binder and fired to obtain a capacitor body.

[0145] The binder removal can be performed under conditions appropriately adjusted according to the main component composition of the dielectric layer and / or the main component composition of the internal electrode. For example, the binder removal can be performed by raising the temperature from 5 °C / hour to 300 °C / hour and holding at 180 °C to 400 °C for 0.5 hour to 24 hours. The binder removal can be performed in an air atmosphere or a reducing atmosphere.

[0146] The firing process can be performed under conditions appropriately adjusted according to the main component composition of the dielectric layer and / or the main component composition of the internal electrode. For example, firing can be performed at 1200 °C to 1350 °C (e.g., 1220 °C to 1300 °C) for 0.5 hour to 8 hours (e.g., 1 hour to 3 hours). The firing atmosphere can be a reducing atmosphere, for example, an atmosphere in which a mixed gas of nitrogen (N2) and hydrogen (H2) is humidified. When the internal electrode includes nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere can be 1.0×10 - 14MPa to 1.0×10 -10 MPa.

[0147] After the firing treatment, annealing may be performed if necessary. Annealing is performed to re-oxidize the dielectric layer, and can be carried out when firing is performed in a reducing atmosphere. Annealing can be performed under conditions appropriately adjusted according to the main component composition of the dielectric layer, etc. For example, annealing can be carried out by raising the temperature at about 50°C / hour to 500°C / hour and annealing at 950°C to 1150°C for more than 0 hours and less than or equal to 20 hours. The annealing atmosphere can be a wet nitrogen (N2) atmosphere, and the oxygen partial pressure can be 1.0×10 -9 MPa to 1.0×10 -5 MPa.

[0148] In the adhesive removal treatment, firing treatment or annealing treatment, in order to moisten nitrogen, mixed gas, etc., a wetting agent, etc. can be used, for example. Among them, the temperature of the wetting agent can be 5°C to 75°C. The adhesive removal treatment, firing treatment and annealing treatment can be carried out continuously or independently.

[0149] Optionally, the third surface and the fourth surface of the obtained capacitor body can be surface-treated by sandblasting, laser irradiation, barrel polishing, etc. This surface treatment can expose the ends of the first internal electrode and the second internal electrode on the third surface and the fourth surface, thereby improving the electrical connection between the first external electrode and the first internal electrode and the electrical connection between the second external electrode and the second internal electrode, and facilitating the formation of an alloy part.

[0150] Subsequently, a paste for a sintered metal layer for the external electrode can be coated on the outer surface of the obtained capacitor body, and then sintered to form a sintered metal layer.

[0151] The paste for forming the sintered metal layer may include a conductive metal and glass. The conductive metal and glass are the same as the above-mentioned conductive metal and glass, and will not be repeated here. In addition, the paste for forming the sintered metal layer may optionally include sub-components such as a binder, a solvent, a dispersant, a plasticizer or an oxide powder. For example, the binder may include ethyl cellulose, acrylic acid, butyraldehyde, etc., and the solvent may include an organic solvent (such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone or toluene) or an aqueous solvent.

[0152] The method of coating a paste for forming a sintered metal layer on the outer surface of a capacitor body may include an impregnation method, various printing methods (such as a screen printing method, etc.), a coating method using a dispenser, a spraying method using a sprayer, etc. The paste for forming a sintered metal layer may be coated on at least the third surface and the fourth surface of the capacitor body, and optionally, on a part of the first surface, the second surface, the fifth surface, and / or the sixth surface where the belt portions for forming the first outer electrode and the second outer electrode will be formed.

[0153] After that, 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.

[0154] Optionally, on the outer surface of the obtained capacitor body, a paste for forming a conductive resin layer is coated and cured to form a conductive resin layer.

[0155] The paste for forming a conductive resin layer may include a resin and a conductive metal, and optionally, may further include a non-conductive filler. The conductive metal and the resin are the same as the above-mentioned conductive metal and resin, and will not be repeated here. In addition, optionally, the paste for forming a conductive resin layer may include sub-components such as an adhesive, a solvent, a dispersant, a plasticizer, or an oxide powder. For example, the adhesive may include ethyl cellulose, acrylic acid, butyral, etc., and the solvent may include an organic solvent (such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, or toluene) or an aqueous solvent.

[0156] For example, the method of forming a conductive resin layer may include: dipping the capacitor body 110 into the paste for forming a conductive resin layer and curing it; screen printing or gravure printing the paste for forming a conductive resin layer on the surface of the capacitor body 110 and curing it; or coating the paste for forming a conductive resin layer on the surface of the capacitor body 110 and then curing it.

[0157] Subsequently, a plating layer is formed outside the conductive resin layer.

[0158] For example, the plating layer may be formed by a plating method, or may be formed by sputtering or electroplating (electrodeposition).

[0159] Hereinafter, specific embodiments of the present disclosure are presented. However, the examples described below are only for specifically illustrating or explaining this embodiment, and the scope of the present disclosure is not limited thereto.

[0160] (Reference Example) By adding ZrO2 to the conductive paste including Ni such that the same amount of Zr as shown in Table 1 below can be included, conductive pastes for forming inner electrodes according to Reference Example 1 to Reference Example 4 are prepared.

[0161] (Experimental Example) Samples were prepared by processing the conductive pastes prepared in Reference Examples 1 to 4 into powder form, and the thermal shrinkage rate (%) according to temperature was measured by changing the temperature from 0 °C to 1000 °C, and is shown in Table 1 and Figure 8 .

[0162] Specifically, measurement was carried out using a thermomechanical analyzer (TMA) with a heating rate of 10 K / min with H2 gas at a concentration of 3%.

[0163] (Table 1)

[0164] Referring to Table 1, it can be seen that, compared with Reference Example 1 that does not include Zr, in Reference Examples 2 to 4 that contain an appropriate amount of Zr, the temperature at the initial shrinkage, the temperature at 5% shrinkage, and the temperature at 15% shrinkage are much higher. In addition, referring to Figure 8 , it can be confirmed that at the same temperature, the thermal shrinkage rate of Reference Examples 2 to 4 is lower. In summary, it can be confirmed that Reference Examples 2 to 4 including an appropriate amount of Zr have higher thermal stability than that of Reference Example 1.

[0165] (Example) Manufacture of Multilayer Capacitor Inventive Example 1 A slurry of a dielectric material including BaTiO3 was prepared, and a green sheet of the dielectric material was manufactured by processing the slurry of the dielectric material using a coating head discharge type roll coater.

[0166] Subsequently, a conductive paste for the internal electrode was prepared by weighing Ni and Zr and mixing Ni and Zr so that the Zr content with respect to the entire internal electrode was 0.001 mol%.

[0167] The conductive paste was printed on the surface of the green sheet, and the green sheets having a conductive paste layer formed thereon were stacked and pressed to prepare a green sheet laminate (width × depth × height = 3.2 mm × 2.5 mm × 2.5 mm).

[0168] The green sheet laminate was degreased at a temperature of 400 °C or lower in a nitrogen atmosphere, and then fired in a hydrogen atmosphere with a firing temperature of 1300 °C or lower and a concentration of 1.0% or lower to manufacture a multilayer capacitor according to Invention Example 1.

[0169] Inventive Examples 2 to 3 and Comparative Examples 1 to 3 In addition to adjusting the Zr content relative to the entire internal electrode as shown in Table 2 below, multilayer capacitors of Invention Examples 2 to 3 and Comparative Examples 1 to 3 were manufactured by the same method as in Invention Example 1.

[0170] (Evaluation Example) Evaluation Example 1: Evaluation of electrode connectivity The electrode connectivity of the multilayer capacitors manufactured in Invention Examples 1 to 3 and Comparative Examples 1 to 3 was evaluated.

[0171] First, for each of Invention Examples 1 to 3 and Comparative Examples 1 to 3, four multilayer capacitors were prepared. After placing the four multilayer capacitors in an epoxy resin mixture and then curing them, the side surfaces of the multilayer capacitors in the W-axis direction and the T-axis direction were polished to the 1 / 2 point of the capacitor body in the L-axis direction. Then, by fixing and holding them in a vacuum atmosphere chamber, cross-sectional samples of the multilayer capacitors cut in the W-axis direction and the T-axis direction at the center of the capacitor body in the L-axis direction were obtained. Then, the cross-sectional samples were observed with a transmission electron microscope (TEM) (observed at a magnification of 200 times) to obtain TEM images.

[0172] Subsequently, an arbitrary internal electrode was selected, an imaginary line was drawn in the W-axis direction, the length of the unbroken part of the internal electrode and the total length of the internal electrode were measured, and the ratio of the length of the unbroken part to the total length of the internal electrode was calculated.

[0173] The relative values of the invention examples and the relative values of the other comparative examples were described by using the ratio of the lengths measured in Comparative Example 1 as the reference value 1.

[0174] Evaluation Example 2: Evaluation of electrical characteristics (BDV, capacitance) and reliability (MTTF) The breakdown voltage (BDV), capacitance, and mean time to failure (MTTF) of the multilayer capacitors manufactured in Invention Examples 1 to 3 and Comparative Examples 1 to 3 were evaluated, and the results are shown in Table 2.

[0175] To measure the BDV, for each of Invention Examples 1 to 3 and Comparative Examples 1 to 3, 50 multilayer capacitors were prepared. A voltage was applied in a scanning manner from 0 V to 1100 V in increments of 1.00000 V by using a Keithley meter model 2410, and the voltage value when the current value became 20 mA was measured as the breakdown voltage value, and the average breakdown voltage value of the 50 multilayer capacitors of each example was calculated as the breakdown voltage of each example. The breakdown voltage was measured in a silicone oil bath. By using the BDV of Comparative Example 1 as the reference value 1, the relative values of the invention examples and the relative values of the other comparative examples were described.

[0176] The electrostatic capacitance was measured using an LCR meter (an instrument for testing inductance, capacitance, and resistance) at 1 kHz and AC 0.5 V. In Table 2, the relative values of the inventive examples and the relative values of the other comparative examples were described using the electrostatic capacitance of Comparative Example 1 as the reference value 1.

[0177] The mean time to failure (MTTF) values were measured by subjecting 400 samples of each inventive example and comparative example to a temperature load test at 125 °C and 8 V. At this time, the time when the insulation resistance decreased to 10 kΩ was determined as the failure time and the average value of the failure times was calculated. The MTTF value of Comparative Example 1 was used as the reference value 1, and the relative values of the inventive examples and the relative values of the other comparative examples were described in Table 2.

[0178] (Table 2)

[0179] Referring to Table 2, it can be confirmed that as the Zr content in the inner electrode in Inventive Examples 1 to 3 increased from 0.001 mol% to 1.0 mol%, the electrode connectivity increased due to the delayed effect of inner electrode shrinkage, and thus the capacitance also increased.

[0180] However, in Comparative Example 2, an excessive amount of Zr diffused into the dielectric layer to inhibit the grain growth of the dielectric grains, resulting in a decrease in electrode connectivity and capacitance compared to Comparative Example 1.

[0181] Furthermore, it can be confirmed that in the case of Inventive Examples 1 to 3, due to the increase in the interfacial reliability between the dielectric layer and the inner electrode, the breakdown voltage (BDV) and MTTF (mean time to failure) increased, and thus the reliability increased.

[0182] However, it can be confirmed that in the case of Comparative Example 3 including an excessive amount of Zr, compared to Comparative Example 1, the electrode connectivity and capacitance decreased, and the BDV and MTTF decreased.

[0183] Although the present disclosure has been described in connection with what is presently considered to be practical example embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments. In contrast, the present disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A multilayer capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as An external electrode is disposed on the capacitor body, wherein each of the inner electrode and the dielectric layer comprises Zr, and The average content of Zr in the inner electrode relative to all components of the inner electrode is greater than or equal to 0.0005 mol % and less than 5.0 mol %.

2. The multilayer capacitor according to claim 1, wherein The inner electrode further includes a conductive metal other than Zr.

3. The multilayer capacitor of claim 1, wherein: The dielectric layer includes a main component and a subcomponent, and The main components include: 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995≤m≤1.010, 0≤x≤0.10, 0 <y≤0.20;Ba m (Ti 1-x Zr x )O3, wherein 0.995≤m≤1.010, x≤0.10; or a combination thereof.

4. The multilayer capacitor according to claim 1, wherein An average content of Zr in the inner electrode is 0.001 mol % to 1.0 mol % with respect to the entire components of the inner electrode.

5. The multilayer capacitor of claim 1, wherein: the dielectric layer includes a central portion in a thickness direction and an interface portion, the interface portion being located on both surfaces of the central portion of the dielectric layer and contacting the internal electrode, The average content of Zr in the interface portion relative to the total components of the interface portion of the dielectric layer is 0.001 mol % to 10.0 mol %, and The average content of Zr in the central portion relative to the total components of the central portion of the dielectric layer is 0 mol % to 2.0 mol %.

6. The multilayer capacitor of claim 5, wherein: The dielectric layer includes a plurality of dielectric grains. The plurality of dielectric grains include first dielectric grains located in the interface portion of the dielectric layer and second dielectric grains located in the central portion of the dielectric layer, and The average grain size of the first dielectric grains is smaller than the average grain size of the second dielectric grains.

7. The multilayer capacitor of claim 6, wherein: The average particle size of the first dielectric grains is 50 nm to 200 nm, and The average grain size of the second dielectric grains is 150 nm to 500 nm.

8. The multilayer capacitor according to claim 1, wherein The average thickness of the dielectric layer is 0.1µm to 5µm.

9. The multilayer capacitor according to claim 1, wherein The average thickness of the inner electrode is 0.1µm to 2µm.

10. A multilayer capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as An external electrode is disposed on the capacitor body, wherein the inner electrode comprises Zr and a conductive metal other than Zr, Wherein, the dielectric layer comprises: (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995≤m≤1.010, 0≤x≤0.10, 0 <y≤0.20;Ba m (Ti 1-x Zr x )O3, wherein 0.995≤m≤1.010, x≤0.10; or a combination thereof, and The average content of Zr in the inner electrode relative to all components of the inner electrode is greater than or equal to 0.0005 mol % and less than 5.0 mol %.

11. The multilayer capacitor according to claim 10, wherein An average content of Zr in the inner electrode is 0.001 mol % to 1.0 mol % with respect to the entire components of the inner electrode.

12. The multilayer capacitor of claim 10, wherein: The dielectric layer includes a central portion in a thickness direction and an interface portion located on both surfaces of the central portion and contacting the internal electrode, The average content of Zr in the interface portion relative to the total components of the interface portion of the dielectric layer is 0.001 mol % to 10.0 mol %, and The average content of Zr in the central portion relative to the total components of the central portion of the dielectric layer is 0 mol % to 2.0 mol %.

13. The multilayer capacitor of claim 12, wherein: The dielectric layer includes a plurality of dielectric grains. The plurality of dielectric grains include first dielectric grains located in the interface portion of the dielectric layer and second dielectric grains located in the central portion of the dielectric layer, and The average grain size of the first dielectric grains is smaller than the average grain size of the second dielectric grains.

14. The multilayer capacitor of claim 13, wherein: The average particle size of the first dielectric grains is 50 nm to 200 nm, and The average grain size of the second dielectric grains is 150 nm to 500 nm.

15. The multilayer capacitor according to claim 10, wherein The average thickness of the dielectric layer is 0.1µm to 5µm.

16. The multilayer capacitor according to claim 10, wherein The average thickness of the inner electrode is 0.1µm to 2µm.

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