Multilayer capacitor

Abstract

The present disclosure provides a multilayer capacitor including: a capacitor body including a dielectric layer and an inner electrode; and an external electrode disposed on the capacitor body. The dielectric layer includes a central portion of the dielectric layer and an interface portion of the dielectric layer, the interface portion of the dielectric layer being located on a surface of the central portion of the dielectric layer and being in contact with the inner electrode, the interface portion of the dielectric layer including Sn. The inner electrode may include a first compound represented by Chemical Formula 1. The inner electrode may include a second compound represented by Chemical Formula 2.

Description

Technical Field

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

[0002] Recently, with the rapid development of the multifunctionalization and miniaturization of electronic devices, the miniaturization and performance improvement of electronic components have also rapidly advanced. In addition, the demand for high reliability of electrical devices used in automobiles, network devices, etc. and electronic devices used in industry has also significantly increased.

[0003] To meet such market demands, the competition in the technology development of passive components such as inductors, capacitors, or resistors is accelerating. In particular, much effort is needed to dominate the market by developing applications of passive components and using various multilayer ceramic capacitor (MLCC) products that are increasingly in use.

[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, and televisions (TVs) (including liquid crystal displays (LCDs)).

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

[0006] However, if the materials are microparticleized, their melting points decrease, which may lower the thermal shrinkage start temperature of the materials. In particular, since the thermal shrinkage start temperature of the metal material included in the internal electrode decreases faster than that of the ceramic material included in the dielectric layer, there is a large thermal shrinkage temperature difference between the dielectric layer and the internal electrode.

[0007] The greater the thermal shrinkage temperature difference between the dielectric layer and the internal electrode, the more likely the electrode connectivity after sintering the dielectric layer and the internal electrode will deteriorate, resulting in deterioration of the capacitance and reliability of the multilayer capacitor.

[0008] Currently, in order to reduce the thermal shrinkage temperature difference between the dielectric layer and the internal electrode, the internal electrode is manufactured by adopting a method of adding a nano-sized barium titanate (BaTiO3) co-material.

[0009] However, since the content of the barium titanate co-material increases, which reduces the layer density of the internal electrode, the co-material may diffuse more into the dielectric layer during sintering, which may increase the thickness of the dielectric layer, resulting in the side effect of reducing the capacitance of the capacitor. Summary of the Invention

[0010] One aspect of the present disclosure provides a multilayer capacitor having excellent reliability due to excellent electrode connectivity and interfacial bonding force.

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

[0012] The multilayer capacitor according to an embodiment includes: a capacitor body including a dielectric layer and an internal electrode; and an external electrode located on the capacitor body, wherein the dielectric layer includes a central portion and an interfacial portion, the interfacial portion is located on the surface of the central portion and contacts the internal electrode, the interfacial portion of the dielectric layer includes Sn, and the internal electrode includes a first compound represented by Chemical Formula 1.

[0013] [Chemical Formula 1] M n+1 A 1-x Sn x X n , In Chemical Formula 1, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, A includes at least one selected from Group 11 elements, Group 12 elements, Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements, X includes C, N, or a combination thereof, 0 < x ≤ 1, and n is an integer from 1 to 4.

[0014] M may include Ti, Zr, Hf, Nb, or a combination thereof.

[0015] The first compound may include Ti2SnC, Zr2SnC, Nb2SnC, Hf2SnC, Hf2SnN, Ti3SnC2, or a combination thereof.

[0016] The Sn content at the interfacial portion of the dielectric layer may be about 0.1 at% to about 0.5 at%.

[0017] The internal electrode may include a central portion and an interfacial portion, the interfacial portion of the internal electrode is located on the surface of the central portion of the internal electrode and contacts the dielectric layer, the internal electrode may further include a third compound represented by Chemical Formula 3, and the central portion of the internal electrode may include the first compound and the third compound.

[0018] [Chemical Formula 3] M n+1 X n , In Chemical Formula 3, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, X includes C, N, or a combination thereof, and n is an integer from 1 to 4.

[0019] The inner electrode may further include Sn, and the interface portion of the inner electrode may include Sn and the third compound.

[0020] The third compound may include Ti2C, Zr2C, Nb2C, Hf2C, Hf2N, Ti3C2, or a combination thereof.

[0021] The Sn content at the interface portion of the inner electrode may be from about 0.01 at% to about 0.3 at%.

[0022] The interface portion of the dielectric layer may further include a main component and a secondary component, The central portion of the dielectric layer may include the main component and the secondary component, wherein 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-y Sn y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), or a combination thereof.

[0023] The secondary component may include dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), 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.

[0024] A may be present and may include Al, Ga, In, Tl, Si, Ge, Sn, Pb, Zn, Cd, P, As, S, Cu, Au, or a combination thereof.

[0025] A multilayer capacitor according to another embodiment includes: a capacitor body including a dielectric layer and an internal electrode; and an external electrode disposed on the capacitor body, wherein the dielectric layer includes a central portion and an interface portion, the interface portion being located on a surface of the central portion and in contact with the internal electrode, the interface portion of the dielectric layer includes Sn, and the internal electrode includes Sn and a second compound represented by Chemical Formula 2.

[0026] [Chemical Formula 2] M n+1 AX n , In Chemical Formula 2, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, A includes at least one selected from Group 11 elements, Group 12 elements, Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements, X includes C, N, or a combination thereof, and n is an integer from 1 to 4.

[0027] The second compound may include Ti2CdC, Sc2InC, Sc2SnC, Ti2AlC, Ti2GaC, Ti2InC, Ti2TlC, V2AlC, V2GaC, Cr2GaC, Ti2AlN, Ti2GaN, Ti2InN, V2GaN, Cr2GaN, Ti2GeC, Ti2SnC, Ti2PbC, V2GeC, Cr2AlC, Cr2GeC, V2PC, V2AsC, Ti2SC, Zr2InC, Zr2TlC, Nb2AlC, Nb2GaC, Nb2InC, Mo2GaC, Zr2InN, Zr2TlN, Zr2SnC, Zr2PbC, Nb2SnC, Nb2PC, Nb2AsC, Zr2SC, Nb2SC, Hf2InC, Hf2TlC, Ta2AlC, Ta2GaC, Hf2SnC, Hf2PbC, Hf2SnN, Hf2SC, Zr2AlC, Ti2ZnC, Ti2ZnN, V2ZnC, Nb2CuC, Mn2GaC, Mo2AuC, Ti2AuN, Ti3AlC2, Ti3GaC2, Ti3InC2, V3AlC2, Ti3SiC2, Ti3GeC2, Ti3SnC2, Ta3AlC2, Ti3ZnC2, Zr3AlC2, Ti4AlN3, V4AlC3, Ti4GaC3, Ti4SiC3, Ti4GeC3, Nb4AlC3, Ta4AlC3, (Mo,V)4AlC3, Mo4VAlC4, or a combination thereof.

[0028] The Sn content at the interface portion of the dielectric layer may be from about 0.1 at% to about 0.5 at%.

[0029] The inner electrode may include a central portion and an interface portion. The interface portion of the inner electrode is located on the surface of the central portion of the inner electrode and is in contact with the dielectric layer. The inner electrode may further include a third compound represented by Chemical Formula 3, and the central portion of the inner electrode may include the second compound and the third compound.

[0030] [Chemical Formula 3] M n+1 X n , In Chemical Formula 3, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, X includes C, N, or a combination thereof, and n is an integer from 1 to 4.

[0031] The internal electrode may further include Sn, and the interface portion of the internal electrode may include Sn and the third compound.

[0032] The third compound may include Ti2C, Zr2C, Nb2C, Hf2C, Hf2N, Ti3C2, or a combination thereof.

[0033] The Sn content at the interface portion of the internal electrode may be from about 0.01 at% to about 0.3 at%.

[0034] The interface portion of the dielectric layer may further include a main component and a sub-component. The central portion of the dielectric layer may include the main component and the sub-component. Wherein, 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-y Sn y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), or a combination thereof.

[0035] The sub-component may include dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), 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.

[0036] The multilayer capacitor according to the embodiment has the advantage of excellent reliability due to excellent electrode connectivity and interfacial bonding strength.

[0037] However, the various beneficial advantages and effects of the present disclosure are not limited to the above description, and can be more easily understood during the process of explaining the specific embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a perspective view showing a multilayer capacitor according to an embodiment.

[0039] Figure 2 is a cross-sectional view of the multilayer capacitor taken along the line I-I’ in Figure 1

[0040] Figure 3 is a perspective exploded view showing the Figure 1 capacitor body.

[0041] Figure 4 is a scanning electron microscope (SEM) image of a part of a cross-section of a multilayer capacitor according to an embodiment.

[0042] Figure 5A and Figure 5B are each a graph showing the elemental content (atomic %) analyzed by scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) in the central part of the inner electrode at the positions (a) and (b) shown in Figure 4 respectively.

[0043] Figure 5C is a graph showing the elemental content (atomic %) analyzed by SEM-EDS in the interface part of the inner electrode at the position (c) shown in Figure 4

[0044] Figure 5D is a graph showing the elemental content (atomic %) analyzed by SEM-EDS in the interface part of the dielectric layer at the position (d) shown in Figure 4

[0045] Figure 5E is a graph showing the elemental content (atomic %) analyzed by SEM-EDS in the central part of the dielectric layer at the position (e) shown in Figure 4 DETAILED DESCRIPTION

[0046] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the drawings so that those skilled in the art can easily implement them. The drawings and the description are considered to be illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals denote the same elements. In addition, the drawings are provided to help easily understand the exemplary embodiments disclosed in this specification, and the technical spirit disclosed in this specification is not limited by the drawings, and it should be understood that the present disclosure includes all modifications, equivalents, and alternatives included in the spirit and technical scope of the present disclosure.

[0047] ​​​​Terms including ordinal numbers (such as first and second) are used to describe various components, but the components are not limited by these terms. These terms are only used to distinguish one component from another.

[0048] When a component is referred to as being "connected" or "coupled" to another component, it should be understood that the component can be directly connected or coupled to the other component, or there can be other intermediate components. In contrast, when a component is referred to as being "directly connected" or "directly coupled" to another component, it should be understood that there are no other intermediate components.

[0049] In this specification, it should be understood that the terms "comprising" and "having" are intended to specify the presence of the features, quantities, steps, operations, components, and assemblies described in the specification, or combinations thereof, and do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, and assemblies, or combinations thereof. Thus, unless explicitly described to the contrary, the words "comprising" and variants such as "including" or "containing" will be understood to imply the inclusion of the stated elements without precluding any other elements.

[0050] Figure 1 is a perspective view showing a multilayer capacitor 100 according to an embodiment, Figure 2 is along Figure 1 a cross-sectional view of the multilayer capacitor 100 taken along line I-I' in Figure 3 and is a perspective exploded view showing Figure 1 the capacitor body 110 of

[0051] For a clear description of this embodiment, the directions are defined as follows: 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) can be a direction perpendicular to the wide surface (main surface) of the sheet-like component. For example, it can be used as a concept same as the stacking direction of the stacked dielectric layers 111. The length direction (L-axis direction) can be a direction extending parallel to the wide surface (main surface) of the sheet-like component and generally perpendicular to the thickness direction (T-axis direction). For example, it can be the direction in which the first outer electrode 131 and the second outer electrode 132 face each other. The width direction (W-axis direction) can be a direction extending parallel to the wide surface (main surface) of the sheet-like component and generally perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length of the sheet-like component in the length direction (L-axis direction) can be longer than the length of the sheet-like component in the width direction (W-axis direction).

[0052] Refer to Figures 1 to 3, according to an embodiment, the multilayer capacitor 100 may include a capacitor body 110 and external electrodes 131 and 132 disposed on the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 disposed on opposite ends of the capacitor body 110 in the length direction (L-axis direction).

[0053] The capacitor body 110 may have a shape such as an approximate hexahedron.

[0054] In the present embodiment, for ease of explanation, in the capacitor body 110, two surfaces opposite to each other in the thickness direction (T-axis direction) are defined as a first surface and a second surface, two surfaces bonded to the first surface and the second surface and opposite to each other in the length direction (L-axis direction) are defined as a third surface and a fourth surface, and two surfaces bonded to the first surface and the second surface, bonded to the third surface and the fourth surface and opposite to each other in the width direction (W-axis direction) are defined as a fifth surface and a sixth surface.

[0055] As an example, the first surface as the lower surface may be a mounting surface. In addition, the first surface to the sixth surface may be flat; however, the present exemplary embodiment is not limited thereto. For example, the first surface to the sixth surface may be curved surfaces having a convex central portion, and the boundary (i.e., the edge) of each surface may be rounded.

[0056] The shape and size of the capacitor body 110 and the number of stacked dielectric layers 111 are not limited to the shape and size of the capacitor body 110 and the number of stacked dielectric layers 111 shown in the drawings of the present embodiment.

[0057] The capacitor body 110 is formed by stacking a plurality of dielectric layers 111 in the thickness direction (T-axis direction) and sintering them, and includes 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 disposed 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.

[0058] In this case, adjacent dielectric layers 111 in the capacitor body 110 may be integrated such that it is difficult to see the boundary between the dielectric layers without using a scanning electron microscope (SEM).

[0059] In addition, the capacitor body 110 may include an active region and covering regions 112 and 113.

[0060] The effective region is the part that contributes to the formation of the capacitance of the multilayer capacitor 100. As an example, the effective region may be the region where the first inner electrode 121 and the second inner electrode 122 stacked along the thickness direction (T-axis direction) overlap.

[0061] The cover regions 112 and 113 are edge portions in the thickness direction and may be positioned on the upper and lower surfaces of the effective region in the thickness direction (T-axis direction). These cover regions 112 and 113 may be respectively stacked on the upper and lower surfaces of the effective region and may each be composed of a single dielectric layer or two or more dielectric layers.

[0062] In addition, the capacitor body 110 may further include side cover regions. The side cover regions are edge portions in the width direction and may be respectively positioned on the two side surfaces of the effective region in the width direction (W-axis direction). These side cover regions may be formed by stacking dielectric green sheets having a conductive paste layer for forming inner electrodes and sintering them. When a conductive paste layer is formed on the surface of the dielectric green sheet, the conductive paste may be coated only on some parts of the surface of the dielectric green sheet and may not be coated on the two side edges of the surface of the dielectric green sheet.

[0063] The cover regions 112 and 113 and the side cover regions are used to prevent damage to the first inner electrode 121 and the second inner electrode 122 due to physical stress and / or chemical stress.

[0064] Inner electrode The first inner electrode 121 and the second inner electrode 122 are electrodes having different polarities and may be alternately arranged along the T-axis direction such that the adjacent first inner electrode and the second inner electrode face each other and a dielectric layer 111 is interposed between the adjacent first inner electrode and the second inner electrode, and one end of each inner electrode may be exposed from the third surface or the fourth surface of the capacitor body 110.

[0065] The first inner electrode 121 and the second inner electrode 122 may be electrically insulated from each other by the dielectric layer 111 provided therebetween.

[0066] The ends of the first inner electrode 121 and the ends of the second inner electrode 122 alternately exposed from the third surface and the fourth surface of the capacitor body 110 may be electrically connected to the first outer electrode 131 and the second outer electrode 132, respectively.

[0067] In an embodiment, the inner electrodes 121 and 122 include a first compound represented by Chemical Formula 1.

[0068] [Chemical Formula 1] M n+1 A 1-x Sn x X n , In Chemical Formula 1, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, A includes at least one selected from Group 11 elements to Group 16 elements, X includes C, N, or a combination thereof, 0 < x ≤ 1, and n is an integer from 1 to 4.

[0069] As an example, M may include Ti, Zr, Hf, Nb, or a combination thereof.

[0070] As an example, A may include any one or more selected from Group 11 elements to Group 16 elements. As an example, A may include Group 13 elements, Group 14 elements, and a combination thereof. As a specific example, A may include Al, Ga, In, Tl, Si, Ge, Sn, Pb, Zn, Cd, P, As, S, Cu, Au, or a combination thereof.

[0071] As a specific example, the first compound may include Ti2SnC, Zr2SnC, Nb2SnC, Hf2SnC, Hf2SnN, Ti3SnC2, or a combination thereof.

[0072] The first compound may be a MAX phase compound including Sn.

[0073] The MAX phase compound is a compound having both metallic properties and ceramic properties, and is characterized by excellent thermal conductivity and electrical conductivity, as well as high strength and modulus.

[0074] For example, the MAX phase compound has a sintering temperature higher than that of a metal such as Ni. Therefore, there may be no significant difference between the sintering temperature of the MAX phase compound and the sintering temperature of the dielectric material of the dielectric layer 111. Therefore, when the inner electrodes 121 and 122 including the MAX phase compound and the dielectric layer 111 are sintered together, there will be no problem of mismatch between the inner electrodes 121 and 122 and the dielectric layer 111. Therefore, the electrode connectivity can be significantly improved by preventing the disconnection or thickness expansion of the inner electrodes 121 and 122.

[0075] As an example, when the conductive paste for forming the inner electrode including the first compound is coated on the dielectric green sheet and sintered simultaneously, Sn may decompose in a part of the first compound and diffuse into the interface between the dielectric layer 111 and the inner electrodes 121 and 122.

[0076] As an example, the first compound can form a bonding portion at the interface between the dielectric layer 111 and the inner electrodes 121 and 122 through transient liquid diffusion bonding during the sintering process.

[0077] As a specific example, during the process of sintering the first compound, Sn is decomposed out, and Sn temporarily exists in the liquid form at the interface between the dielectric layer 111 and the inner electrodes 121 and 122, and when the formed liquid material solidifies at the isothermal temperature, the dielectric layer 111 and the inner electrodes 121 and 122 can be bonded.

[0078] In another embodiment, the inner electrodes 121 and 122 include Sn and a second compound represented by Chemical Formula 2.

[0079] [Chemical Formula 2] M n+1 AX n , In Chemical Formula 2, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, A includes at least one selected from Group 11 elements to Group 16 elements, X includes C, N, or a combination thereof, and n is an integer from 1 to 4.

[0080] As an example, A can include Group 13 elements, Group 14 elements, and combinations thereof. As a specific example, A can include Al, Ga, In, Tl, Si, Ge, Sn, Pb, Zn, Cd, P, As, S, Cu, Au, or a combination thereof.

[0081] As an example, the second compound may include Ti2CdC, Sc2InC, Sc2SnC, Ti2AlC, Ti2GaC, Ti2InC, Ti2TlC, V2AlC, V2GaC, Cr2GaC, Ti2AlN, Ti2GaN, Ti2InN, V2GaN, Cr2GaN, Ti2GeC, Ti2SnC, Ti2PbC, V2GeC, Cr2AlC, Cr2GeC, V2PC, V2AsC, Ti2SC, Zr2InC, Zr2TlC, Nb2AlC, Nb2GaC, Nb2InC, Mo2GaC, Zr2InN, Zr2TlN, Zr2SnC, Zr2PbC, Nb2SnC, Nb2PC, Nb2AsC, Zr2SC, Nb2SC, Hf2InC, Hf2TlC, Ta2AlC, Ta2GaC, Hf2SnC, Hf2PbC, Hf2SnN, Hf2SC, Zr2AlC, Ti2ZnC, Ti2ZnN, V2ZnC, Nb2CuC, Mn2GaC, Mo2AuC, Ti2AuN, Ti3AlC2, Ti3GaC2, Ti3InC2, V3AlC2, Ti3SiC2, Ti3GeC2, Ti3SnC2, Ta3AlC2, Ti3ZnC2, Zr3AlC2, Ti4AlN3, V4AlC3, Ti4GaC3, Ti4SiC3, Ti4GeC3, Nb4AlC3, Ta4AlC3, (Mo,V)4AlC3, Mo4VAlC4, or a combination thereof.

[0082] The second compound is different from the aforementioned first compound and may be a general MAX-phase compound in which A may or may not include Sn.

[0083] When a conductive paste for forming an inner electrode including the second compound and Sn is coated on a dielectric green sheet and sintered simultaneously, Sn may diffuse into the interface between the dielectric layer 111 and the inner electrodes 121 and 122.

[0084] As an example, in the process of sintering the second compound and Sn, Sn diffuses into the interface between the dielectric layer 111 and the inner electrodes 121 and 122 and exists in a liquid form, and when the formed liquid material solidifies at an isothermal temperature, the dielectric layer 111 and the inner electrodes 121 and 122 may be bonded.

[0085] When the dielectric layer 111 and the inner electrodes 121 and 122 are bonded by the aforementioned method, the interfacial bonding force is improved by the liquid material formed at the interface, such that the two layers can be easily bonded, and the mechanical properties of the bonded portion can be improved.

[0086] In addition, a bonding portion having physical and chemical properties similar to those of the materials included in the dielectric layer 111 and the internal electrodes 121 and 122 is formed, thereby reducing the difference in the thermal shrinkage temperature between the internal electrodes 121 and 122 and the dielectric layer 111, and thus suppressing interfacial peeling and cracking.

[0087] Therefore, due to the improved interfacial bonding force between the internal electrodes 121 and 122 and the dielectric layer 111, stable capacitor characteristics (e.g., reliability, electrical characteristics, etc.) can be achieved.

[0088] Figure 4 is a scanning electron microscope (SEM) image of a part of the cross-section of a multilayer capacitor according to an embodiment. The SEM image of the cross-section of the multilayer capacitor can be obtained as follows.

[0089] First, the multilayer capacitor 100 is placed in an epoxy resin mixture and cured, and the surfaces of the multilayer capacitor 100 in the L-axis direction and the T-axis direction are polished to the 1 / 2 point of the capacitor body 110 in the W-axis direction, and then placed in a vacuum chamber, thereby preparing a cross-section sample (hereinafter referred to as "cross-section sample") of the multilayer capacitor 100 cut along the L-axis direction and the T-axis direction from the center of the capacitor body 110 in the W-axis direction. Then, the cross-section sample is observed with a scanning electron microscope (SEM) to obtain an SEM image.

[0090] Refer to Figure 4 , the central portions of the internal electrodes 121 and 122 and the interfacial portions of the internal electrodes 121 and 122 can be confirmed as follows: by binarizing the SEM image of the cross-section sample, for example, to distinguish the portions with light and dark differences.

[0091] Refer to Figure 4 , the internal electrodes 121 and 122 may include the central portions of the internal electrodes 121 and 122 and the interfacial portions of the internal electrodes 121 and 122. The interfacial portions of the internal electrodes 121 and 122 are provided on the surfaces of the central portions of the internal electrodes 121 and 122 and are in contact with the dielectric layer 111.

[0092] The central portions of the internal electrodes 121 and 122 may refer to: in the cross-section of the multilayer capacitor 100 cut along the L-axis direction and the T-axis direction from the center of the capacitor body 110 in the W-axis direction, in the T-axis direction, the midpoint between a point on one surface of any one of the internal electrodes and the point on the other surface of the internal electrode located at the shortest distance from the point. In addition, the central portions of the internal electrodes 121 and 122 may refer not only to the midpoint but also to the region within ±30% of 1 / 2 of the thickness of the internal electrode in the T-axis direction based on the midpoint.

[0093] The interface portion of the inner electrodes 121 and 122 may be an area of the inner electrodes 121 and 122 other than the central portion, and may refer to an area extending 5 µm from the interface provided between the dielectric layer 111 and the inner electrodes 121 and 122 toward the central portion of the inner electrodes 121 and 122 along the T-axis direction.

[0094] As an example, the interface portion of the inner electrodes 121 and 122 may refer to a point that is about 1 / 4 of the thickness of the inner electrode from the interface provided between the dielectric layer 111 and the inner electrodes 121 and 122 toward the central portion of the inner electrodes 121 and 122 in the T-axis direction.

[0095] In addition, the interface portion of the inner electrodes 121 and 122 may refer not only to the above point, but also to an area within ±30% of 1 / 4 of the thickness of the inner electrode in the T-axis direction based on this point.

[0096] As an example, the central portion of the inner electrodes 121 and 122 may include a first compound and a third compound represented by Chemical Formula 3.

[0097] As another example, the central portion of the inner electrodes 121 and 122 may include a second compound and a third compound represented by Chemical Formula 3.

[0098] As an example, the interface portion of the inner electrodes 121 and 122 may include Sn and a third compound represented by Chemical Formula 3.

[0099] [Chemical Formula 3] M n+1 X n , In Chemical Formula 3, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, X includes C, N, or a combination thereof, and n is an integer from 1 to 4.

[0100] As an example, M may include Ti, Zr, Hf, Nb, or a combination thereof.

[0101] As a specific example, the third compound may include Ti2C, Zr2C, Nb2C, Hf2C, Hf2N, Ti3C2, or a combination thereof.

[0102] The third compound may be a compound of Sn and A after decomposition and release from the aforementioned first compound and / or a compound of A after decomposition and release from the aforementioned second compound.

[0103] As an example, when sintering a conductive paste for forming an internal electrode including a first compound, Sn contained in the first compound may decompose and exist at the interface portion between the internal electrodes 121 and 122, and a third compound as a compound after Sn decomposes and is released may be included in the central portion of the internal electrodes 121 and 122, the interface portion between the internal electrodes 121 and 122, or both the central portion of the internal electrodes 121 and 122 and the interface portion between the internal electrodes 121 and 122.

[0104] As another example, when sintering a conductive paste for forming an internal electrode including a second compound and Sn, Sn may diffuse and exist at the interface portion between the internal electrodes 121 and 122, and a third compound as a compound after A decomposes and is released from the second compound may be included in the central portion of the internal electrodes 121 and 122, the interface portion between the internal electrodes 121 and 122, or both the central portion of the internal electrodes 121 and 122 and the interface portion between the internal electrodes 121 and 122.

[0105] Figure 5A and Figure 5B are each a graph showing the elemental content (atomic %) analyzed by SEM-EDS in the central portion of the internal electrode at positions (a) and (b) shown respectively in Figure 4 The graph shows the elemental content (atomic %) analyzed by SEM-EDS in the interface portion of the internal electrode at position (c) shown in Figure 5C is a graph showing Figure 4 The elemental content (atomic %) analyzed by SEM-EDS in the interface portion of the internal electrode at position (c) shown in

[0106] For example, the Sn content (atomic %, at%) at the interface portion between the internal electrodes 121 and 122 may be greater than or equal to about 0.01 at%, greater than or equal to about 0.05 at%, or greater than or equal to about 0.1 at%, and less than or equal to about 0.3 at%, less than or equal to about 0.2 at%, or less than or equal to about 0.15 at%. If the above numerical range is satisfied, a multilayer capacitor having excellent electrode connectivity and interfacial bonding strength can be achieved. The Sn content can be measured using SEM-EDS. Even if not described in the present disclosure, other methods and / or other tools understood by those of ordinary skill in the art can be used.

[0107] As an example, the internal electrodes 121 and 122 may further include a conductive metal, and the conductive metal may include metals such as Ni, Cu, Ag, Pd, or Au or their alloys (such as Ag-Pd alloy).

[0108] In addition, the first internal electrode 121 and the second internal electrode 122 may include dielectric particles having the same compositional system as the ceramic material included in the dielectric layer 111.

[0109] The first internal electrode 121 and the second internal electrode 122 can be formed using a conductive paste including a conductive metal. The printing method of the conductive paste can be a screen printing method, a gravure printing method, etc.

[0110] As an example, the average thickness of the first internal electrode 121 and the average thickness of the second internal electrode 122 can be greater than or equal to about 0.05 µm, greater than or equal to about 0.1 µm, greater than or equal to about 0.2 µm, or greater than or equal to about 0.25 µm, and less than or equal to about 10 µm, less than or equal to about 5 µm, or less than or equal to about 1 µm.

[0111] The average thickness of the first internal electrode 121 and / or the second internal electrode 122 can be measured by the following method.

[0112] The average thickness of the first internal electrode 121 and / or the second internal electrode 122 can be: in the scanning electron microscope (SEM) image of the cross-sectional sample, using the central point of the first internal electrode 121 and / or the second internal electrode 122 in the length direction (L-axis direction) as the reference point, the arithmetic average of the thicknesses of the first internal electrode 121 and / or the second internal electrode 122 at 10 points spaced at a predetermined interval from the reference point.

[0113] The interval between the 10 points can be adjusted according to the scale of the SEM image. For example, it can be an interval of about 1 µm to about 100 µm, about 1 µm to about 50 µm, or about 1 µm to about 10 µm. Here, the interval can refer to the interval between two adjacent points.

[0114] In this case, all 10 points should be located within the first internal electrode 121 and / or the second internal electrode 122, and when not all 10 points are located within the first internal electrode 121 and / or the second internal electrode 122, the position of the reference point can be changed or the interval of the 10 points can be adjusted.

[0115] Dielectric layer When manufacturing a multilayer capacitor according to an embodiment, if a conductive paste for forming an internal electrode containing a first compound is coated on a dielectric green sheet and sintered, Sn in the first compound decomposes and diffuses into the dielectric layer 111.

[0116] When manufacturing a multilayer capacitor according to another embodiment, if a conductive paste for forming an internal electrode including a second compound and Sn is coated on a dielectric green sheet and sintered, Sn can diffuse into the dielectric layer 111.

[0117] The diffused Sn can exist at the interface between the dielectric layer 111 and the internal electrodes 121 and 122, thereby realizing a multilayer capacitor having excellent interfacial bonding force between the dielectric layer 111 and the internal electrodes 121 and 122.

[0118] Reference Figure 4 In a multilayer capacitor according to one embodiment, the dielectric layer 111 includes a central portion of the dielectric layer 111 and an interface portion of the dielectric layer 111. The interface portion of the dielectric layer 111 is provided on the surface of the central portion of the dielectric layer 111 and is in contact with the inner electrodes 121 and 122.

[0119] The central portion of the dielectric layer 111 may refer to: in a cross-section of the multilayer capacitor 100 cut along the L-axis direction and the T-axis direction from the center in the W-axis direction of the capacitor body 110, in the T-axis direction, the midpoint between a point on one surface of any dielectric layer and a point on the other surface of the same dielectric layer located at the shortest distance from the point. In addition, the central portion of the dielectric layer 111 may refer not only to the midpoint, but also to a region within ±30% of 1 / 2 of the thickness of the dielectric layer in the T-axis direction based on the midpoint.

[0120] The interface portion of the dielectric layer 111 may be a region of the dielectric layer 111 other than the central portion, and may refer to a region extending 5 µm from the interface provided between the dielectric layer 111 and the inner electrodes 121 and 122 toward the central portion of the dielectric layer 111 along the T-axis direction.

[0121] As an example, the interface portion of the dielectric layer 111 may refer to a point that is about 1 / 4 of the thickness of the dielectric layer from the interface provided between the dielectric layer 111 and the inner electrodes 121 and 122 toward the central portion of the dielectric layer 111 in the T-axis direction.

[0122] In addition, the interface portion of the dielectric layer 111 may refer not only to the above point, but also to a region within ±30% of 1 / 4 of the thickness of the dielectric layer in the T-axis direction based on the point.

[0123] Figure 5D is a graph showing Figure 4 the elemental content (atomic %) analyzed by SEM-EDS in the interface portion of the dielectric layer at the position (d) shown in Figure 5E is a graph showing Figure 4 the elemental content (atomic %) analyzed by SEM-EDS in the central portion of the dielectric layer at the position (e) shown in

[0124] Reference Figure 4 and Figure 5D , the interface portion of the dielectric layer 111 contains Sn.

[0125] As an example, the dielectric layer 111 including the central portion and the interface portion includes a dielectric, and the dielectric may include a main component and a sub-component. Specifically, both the central portion and the interface portion of the dielectric layer 111 may include the main component and the sub-component.

[0126] The base material with the main component being a dielectric has a high dielectric constant and contributes to the formation of the capacitance of the multilayer capacitor 100.

[0127] For example, the main component may be a barium titanate-based compound. For example, it 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-y Sn y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20) or a dielectric material which is a combination thereof.

[0128] For example, the main component may include 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, (Ba, Sr)(Ti,Sn)O3 or a combination thereof.

[0129] For example, the secondary components may include dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), 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.

[0130] The dielectric layer 111 may further include ceramic additives, organic solvents, binders, dispersants or a combination thereof.

[0131] As an example, the Sn content (at%) at the interface portion of the dielectric layer 111 may be greater than or equal to about 0.1 at%, greater than or equal to about 0.15 at% or greater than or equal to about 0.2 at%, and may be less than or equal to about 0.5 at%, less than or equal to about 0.4 at% or less than or equal to about 0.3 at%. If the above numerical ranges are satisfied, a multilayer capacitor having excellent electrode connectivity and interfacial bonding strength can be achieved.

[0132] The Sn content can be measured using SEM-EDS. Even if not described in the present disclosure, other methods and / or other tools understood by those of ordinary skill in the art can be used.

[0133] For example, the average thickness of the dielectric layer 111 may be greater than or equal to about 0.05 µm, greater than or equal to about 0.1 µm or greater than or equal to about 0.2 µm, and may be less than or equal to about 10 µm, less than or equal to about 5 µm or less than or equal to about 1 µm.

[0134] The average thickness of the dielectric layer 111 can be measured by the following method.

[0135] First, a scanning electron microscope (SEM) image is obtained by observing a cross-sectional sample with a scanning electron microscope.

[0136] The average thickness of the dielectric layer 111 can be: in the SEM image of the cross-sectional sample, using the central point in the L-axis direction of the dielectric layer 111 as a reference point, the arithmetic average of the thicknesses of the dielectric layer 111 at 10 points spaced apart from the reference point at a predetermined interval.

[0137] The interval between the 10 points can be adjusted according to the scale of the SEM image. For example, it can be an interval of about 1 µm to about 100 µm, about 1 µm to about 50 µm or about 1 µm to about 10 µm. The interval here can refer to the interval between two adjacent points.

[0138] In this case, all 10 points should be located within the dielectric layer 111, and when not all 10 points are located within the dielectric layer 111, the position of the reference point can be changed or the interval between the 10 points can be adjusted.

[0139] Outer electrode The first outer electrode 131 and the second outer electrode 132 are provided with voltages of different polarities and are respectively electrically connected to the exposed portions of the first inner electrode 121 and the second inner electrode 122.

[0140] According to the above configuration, if a predetermined voltage is applied to the first and second external electrodes 131 and 132, charges are accumulated between the first and second internal electrodes 121 and 122 facing each other. Here, the multilayer capacitor 100 may have a capacitance proportional to an area where the first and second internal electrodes 121 and 122 overlap each other in the T-axis direction in the active region.

[0141] The first outer electrode 131 and the second outer electrode 132 may be respectively disposed on the third surface and the fourth surface of the capacitor body 110, and may respectively include a first connecting portion and a second connecting portion and respectively include a first band portion and a second band portion, the first connecting portion being coupled to the first inner electrode 121, the second connecting portion being coupled to the second inner electrode 122, the first band portion being disposed at an edge where the third surface of the capacitor body 110 intersects with at least one of the first and second surfaces and the fifth and sixth surfaces, and the second band portion being disposed at an edge where the fourth surface of the capacitor body 110 intersects with at least one of the first and second surfaces and the fifth and sixth surfaces.

[0142] The first band portion may extend from the first connection portion to a portion of at least one of the first and second surfaces and the fifth and sixth surfaces of the capacitor body 110, and the second band portion may extend from the second connection portion to a portion of at least one of the first and second surfaces and the fifth and sixth surfaces 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 and second external electrodes 131 and 132 to the capacitor body 110, respectively.

[0143] As an example, each of the first and second external electrodes 131 and 132 may include a sintered metal layer contacting the capacitor body 110 , a conductive resin layer disposed to cover the sintered metal layer, and a plated layer disposed to cover the conductive resin layer.

[0144] The sintered metal layer may include conductive metal and glass.

[0145] As an 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 conductive metal, and the sintered metal layer including copper (Cu) may mean that the sintered metal layer includes copper (Cu) simple substance and / or copper (Cu) alloy. When the conductive metal includes copper, a metal other than copper may be included in an amount of about 5 mol parts or less based on 100 mol parts of copper.

[0146] As an example, the sintered metal layer may include a composition containing an oxide as the glass. For example, it may include one or more selected from silicon oxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides, and alkaline earth metal oxides. The transition metal may be one or more selected from zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal may be one or more selected from lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be one or more selected from magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0147] Optionally, a conductive resin layer is formed on the sintered metal layer. For example, it may be formed to completely cover the sintered metal layer. Additionally, the first outer electrode 131 and the second outer electrode 132 may not include the sintered metal layer. In this case, the conductive resin layer may be in direct contact with the capacitor body 110.

[0148] The conductive resin layer may extend to at least one of the first surface, the second surface, the fifth surface, and the sixth surface of the capacitor body 110, and the length of the region (i.e., the belt portion) where the conductive resin layer extends to at least one of the first surface, the second surface, the fifth surface, and the sixth surface of the capacitor body 110 may be longer than the length of the region (i.e., the belt portion) where the sintered metal layer extends to at least one of the first surface, the second surface, the fifth surface, and the sixth surface of the capacitor body 110. In other words, the conductive resin layer may be formed on the sintered metal layer and may be formed to completely cover the sintered metal layer.

[0149] The conductive resin layer includes a resin and a conductive metal.

[0150] The resin included in the conductive resin layer is not particularly limited as long as it has adhesive properties and shock absorption properties and can be mixed with the conductive metal powder to form a paste, and may include, for example, a phenolic resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

[0151] The conductive metal included in the conductive resin layer is used to electrically connect the first inner electrode 121 and the second inner electrode 122 or the sintered metal layer to the plating layer described below.

[0152] The conductive metal included in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof. In other words, the conductive metal may be formed only in a flake shape, or may be formed only in a spherical shape, or may be in the form of a mixture of a flake shape and a spherical shape.

[0153] Here, the spherical shape may include a shape that is not a completely spherical shape, and may include, for example, a shape in which the ratio of the length of the major axis to the length of the minor axis (major axis / minor axis) may be less than or equal to about 1.45. The flake shape refers to a shape having a flat and elongated shape, and is not particularly limited, for example, the ratio of the length of the major axis to the length of the minor axis (major axis / minor axis) may be greater than or equal to about 1.95.

[0154] The first and second external electrodes 131 and 132 may further include a plating layer disposed outside the conductive resin layer.

[0155] The plating layer may include at least one of nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb) and alloys thereof. As an example, each plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a nickel (Ni) plating layer and a tin (Sn) plating layer stacked in sequence, or may be a tin (Sn) plating layer, a nickel (Ni) plating layer and a tin (Sn) plating layer stacked in sequence. Optionally, each plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0156] The plating layer may improve mountability on a substrate, structural reliability, durability to the outside, heat resistance, and equivalent series resistance (ESR) of the multilayer capacitor 100 .

[0157] Method for manufacturing a multilayer capacitor A method of manufacturing a multilayer capacitor according to another embodiment includes manufacturing a capacitor body including a dielectric layer and an inner electrode, and then forming an outer electrode outside the capacitor body.

[0158] First, the production of the capacitor body will be described.

[0159] In the manufacturing process of the capacitor body, a dielectric paste to be formed into a dielectric layer after sintering and a conductive paste to be formed into an internal electrode after sintering are prepared.

[0160] For example, the dielectric paste is prepared according to the following method. The dielectric powder is uniformly mixed by wet mixing, etc., dried, and heat-treated under predetermined conditions. Subsequently, an organic vehicle or an aqueous vehicle is added to the dielectric powder and further kneaded to prepare the dielectric paste.

[0161] The obtained dielectric paste is formed into a dielectric green sheet by using a technique such as a doctor blade method. In addition, if necessary, the dielectric paste may include an additive selected from various dispersants, plasticizers, binders, subcomponent compounds, and glass.

[0162] In an embodiment, the conductive paste for an internal electrode is prepared by mixing the aforementioned first compound with a binder or a solvent.

[0163] In another embodiment, a conductive paste for an internal electrode is prepared by mixing the aforementioned second compound and Sn with a binder or a solvent. In this case, based on 100 wt% of the conductive paste for the internal electrode, the amount of Sn included may be greater than or equal to about 1 wt% or greater than or equal to about 5 wt%, and less than about 20 wt%, less than or equal to about 15 wt% or less than or equal to about 10 wt%.

[0164] Since the first compound and the second compound are the same as the above-mentioned first compound and second compound, their descriptions are omitted here.

[0165] On the surface of the green dielectric sheet, the conductive paste for the internal electrode is coated in a predetermined pattern by various printing methods such as a screen printing method or a transfer printing method. Subsequently, a plurality of green dielectric sheets having internal electrode patterns are stacked and then pressed in the stacking direction to obtain a green dielectric sheet laminate. Here, green dielectric sheets not including internal electrode patterns may be stacked such that the green dielectric sheet laminate may have green dielectric sheets at the top and bottom in the stacking direction.

[0166] Optionally, the obtained green dielectric sheet laminate may be cut into a predetermined size by cutting or the like.

[0167] Furthermore, if necessary, the green dielectric sheet laminate may be cured and dried to remove a plasticizer or the like, and then barrel polishing may be performed by using a horizontal centrifugal barrel machine or the like. During barrel polishing, unnecessary portions (such as burrs generated during cutting) may be polished by putting the green dielectric sheet laminate, a medium, and a polishing solution into a barrel container and then applying a rotational motion, vibration, etc. to the barrel container. Furthermore, after barrel polishing, the green dielectric sheet laminate may be washed with a cleaning liquid (such as water) and dried.

[0168] The green dielectric sheet laminate is subjected to a binder removal treatment and a sintering treatment to obtain a capacitor body.

[0169] The binder removal treatment is 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 treatment may be performed by raising the temperature at about 5 °C / hour to about 300 °C / hour and maintaining the temperature at about 180 °C to about 400 °C for about 0.5 hour to about 24 hours. The binder removal treatment is performed in an air atmosphere or a reducing atmosphere.

[0170] The sintering treatment can be carried out under conditions appropriately adjusted according to the main component composition of the dielectric layer and / or the main component composition of the inner electrode. For example, the sintering treatment can be carried out at about 1200 °C to about 1350 °C (e.g., about 1220 °C to about 1300 °C) for about 0.5 hours to about 8 hours (e.g., about 1 hour to about 3 hours). The sintering treatment is carried out in a reducing atmosphere, for example, in an atmosphere where a mixed gas of nitrogen (N2) and hydrogen (H2) is humidified.

[0171] After the sintering treatment, annealing can be carried out. Since annealing is a treatment for re-oxidizing the dielectric layer, annealing can be carried out if sintering is carried out in a reducing atmosphere. The annealing treatment is carried out under conditions appropriately adjusted according to the main component composition of the dielectric layer, etc. For example, the annealing treatment can be carried out by raising the temperature at about 50 °C / hour to about 500 °C / hour and maintaining it at about 950 °C to about 1150 °C for more than 0 hours and less than or equal to about 20 hours. In addition, annealing can be carried out in a humidified nitrogen (N2) atmosphere at an oxygen partial pressure of about 1.0×10 -9 MPa to about 1.0×10 -5 MPa.

[0172] The humidified nitrogen, mixed gas, etc. in the binder removal treatment, sintering treatment or annealing treatment can be carried out, for example, by using a wetting agent (such as water), etc., where the temperature of the wetting agent used can be about 5 °C to about 75 °C. The binder removal treatment, sintering treatment and annealing treatment can be carried out continuously or independently.

[0173] Optionally, the third surface and the fourth surface of the capacitor body can be subjected to surface treatment (such as sandblasting, laser irradiation or barrel polishing). This surface treatment can expose the ends of the first inner electrode and the second inner electrode to the third surface and the fourth surface respectively, which can improve the electrical bonding between the first outer electrode and the first inner electrode and the electrical bonding between the second outer electrode and the second inner electrode and facilitate the formation of an alloy part.

[0174] Subsequently, a paste for forming a sintered metal layer is coated on the outside of the obtained capacitor body and sintered to form a sintered metal layer of the outer electrode.

[0175] The paste for forming a sintered metal layer can include a conductive metal and glass. The conductive metal and glass are the same as the conductive metal and glass mentioned above, so they will not be repeated here. In addition, the paste for forming a sintered metal layer can optionally include sub-components such as a binder, a solvent, a dispersant, a plasticizer and / or an oxide powder. For example, the binder can be ethyl cellulose, an acrylic resin or a butyral resin, and the solvent can be an organic solvent (such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone or toluene) or an aqueous solvent.

[0176] Methods of applying a paste for forming a sintered metal layer onto the exterior of a capacitor body may include an immersion method, various printing methods (such as a screen printing method, etc.), a coating method using a dispenser, etc., a spraying method using a sprayer, etc. The paste for forming a sintered metal layer is applied at least on the third and fourth surfaces of the capacitor body, and optionally, on at least a portion of the strip portions on the first, second, fifth, and sixth surfaces where the first and second external electrodes will be formed.

[0177] Subsequently, the capacitor body coated with the paste for forming a sintered metal layer is dried and sintered at about 700 °C to about 1000 °C for about 0.1 hour to about 3 hours to form a sintered metal layer.

[0178] Optionally, on the exterior of the obtained capacitor body, a paste for forming a conductive resin layer is applied and cured to form a conductive resin layer.

[0179] The paste for forming a conductive resin layer may include a resin and a conductive metal, and optionally may also include a non-conductive filler. Since the descriptions of the conductive metal and the resin are the same as those described above, the repeated descriptions will be omitted. In addition, the paste for forming a conductive resin layer may optionally include sub-components such as a binder, a solvent, a dispersant, a plasticizer, and / or an oxide powder. For example, the binder may be ethyl cellulose, an acrylic resin, or a butyral resin, and the solvent may be an organic solvent (such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, or toluene) or an aqueous solvent.

[0180] For example, methods of forming a conductive resin layer may include: immersing the capacitor body 110 in the paste for forming a conductive resin layer and curing it; or printing the paste for forming a conductive resin layer on the surface of the capacitor body 110 by a screen printing method, a gravure printing method, etc. and curing it; or applying the paste for forming a conductive resin layer on the surface of the capacitor body 110 and then curing it.

[0181] Subsequently, a plating layer is formed on the exterior of the conductive resin layer.

[0182] For example, the plating layer may be formed by a plating method, for example, by sputtering or electroplating.

[0183] Hereinafter, specific examples of the present disclosure will be presented. However, the following examples are only intended to specifically illustrate or describe the present disclosure and should not be construed as limiting the scope of the present disclosure.

[0184] (Preparation Example) Example 1 A dielectric green sheet is prepared as follows: A dielectric slurry including BaTiO3 is prepared, and then the dielectric slurry is coated using a coating head discharge type roll coater. Subsequently, a conductive paste for an internal electrode including Ti2SnC is prepared.

[0185] The conductive paste is printed on the surface of the dielectric green sheet, and a plurality of dielectric green sheets having a conductive paste layer are stacked and pressed to fabricate a dielectric green sheet laminate (width × length × height = 3.2 mm × 2.5 mm × 2.5 mm).

[0186] The dielectric green sheet laminate is subjected to an adhesive removal treatment at 400 °C or lower in a nitrogen atmosphere, and sintered at 1300 °C or lower in a hydrogen concentration of 1.0% or lower to fabricate a multilayer capacitor according to Example 1.

[0187] Example 2 A multilayer capacitor according to Example 2 is fabricated in the same manner as in Example 1, except that the conductive paste for the internal electrode is prepared by mixing Ti3AlC2 with Sn instead of Ti2SnC. Here, based on 100 wt% of the conductive paste for the internal electrode, the content of Sn included is 1 wt%.

[0188] Example 3 A multilayer capacitor according to Example 3 is fabricated in the same manner as in Example 2, except that the conductive paste is prepared by mixing Ti3AlC2 with Sn at a content of 5 wt% based on 100 wt% of the conductive paste for the internal electrode.

[0189] Example 4 A multilayer capacitor according to Example 4 is fabricated in the same manner as in Example 2, except that the conductive paste for the internal electrode is prepared by mixing Ti3AlC2 with Sn at a content of 20 wt% based on 100 wt% of the conductive paste for the internal electrode.

[0190] Comparative Example 1 A multilayer capacitor according to Comparative Example 1 is fabricated in the same manner as in Example 1, except that the conductive paste for the internal electrode is prepared by mixing Ni with a co-material (BaTiO3) instead of Ti2SnC.

[0191] Comparative Example 2 A multilayer capacitor according to Comparative Example 2 is fabricated in the same manner as in Example 1, except that the conductive paste for the internal electrode is prepared by using Ti3AlC2 instead of Ti2SnC.

[0192] (Evaluation Example) Evaluation Example 1: Presence of Sn at the interface portion of the dielectric layerWhether or not and measurement of Sn content After each of the multilayer capacitors according to Examples 1 to 4 and Comparative Examples 1 to 2 was placed in an epoxy resin mixture and cured, the surfaces of the multilayer capacitors in the L-axis direction and the T-axis direction were polished to the 1 / 2 point of the capacitor body in the W-axis direction, fixed, and then held in a vacuum atmosphere chamber to obtain cross-sectional samples cut in the L-axis direction and the T-axis direction along the center in the W-axis direction of the multilayer capacitors. Subsequently, the cross-sectional samples were examined with a scanning electron microscope to obtain SEM images.

[0193] SEM-EDS analysis was performed on the SEM images of the cross-sectional samples to measure the presence or absence of Sn and the content of Sn (atomic %).

[0194] Evaluation Example 2: Evaluation of electrode connectivity The electrode connectivity of the multilayer capacitors according to Examples 1 to 4 and Comparative Examples 1 to 2 was evaluated.

[0195] First, the cross-sectional samples were examined with a scanning electron microscope (SEM) to obtain SEM images.

[0196] Subsequently, after arbitrarily selecting an internal electrode from the SEM image and drawing an imaginary line thereon in the L-axis direction, the ratio of the unbroken length of the internal electrode to the total length of the internal electrode was measured.

[0197] After calculating the ratios of the multilayer capacitors of Examples 1 to 4 and Comparative Example 2 relative to the ratio of the multilayer capacitor of Comparative Example 1 (generally written as "○") as a reference, if the ratio is higher than the ratio of Comparative Example 1, it is evaluated as excellent (described as "◎"), but if the ratio is lower than the ratio of Comparative Example 1, it is evaluated as insufficient (described as "△"), and the results are shown in Table 1.

[0198] Evaluation Example 3: Evaluation of reliability (MTTF) The reliability (MTTF, mean time to failure) of the multilayer capacitors of Examples 1 to 4 and Comparative Examples 1 to 2 was evaluated.

[0199] After preparing 400 samples for each of Examples 1 to 4 and Comparative Examples 1 to 2, a high-temperature load test was performed under the conditions of 125°C and 8V to determine when the insulation resistance dropped to 10 kΩ, and this time was determined as the MTTF (mean time to failure).

[0200] After measuring the MTTF of 400 samples for each of Measurement Examples 1 to 4 and Comparative Examples 1 to 2, the MTTF of Comparative Example 1 was set as a reference value (generally written as "○"). If the MTTF of the multilayer capacitor samples of Examples 1 to 4 and Comparative Example 2 was higher than the MTTF of the multilayer capacitor samples of Comparative Example 1, it was evaluated as excellent (written as "◎"), but if the MTTF of the multilayer capacitor samples of Examples 1 to 4 and Comparative Example 2 was lower than the MTTF of the multilayer capacitor samples of Comparative Example 1, it was evaluated as insufficient (written as "△"), and the results are shown in Table 1.

[0201] Evaluation Example 4: Evaluation of capacitance The capacitance of the multilayer capacitor was measured using an LCR meter (an instrument for testing inductance, capacitance, and resistance) under the conditions of 1 kHz and AC 0.5 V, where the capacitance of Comparative Example 1 was set as a reference value (generally written as "○").

[0202] If the capacitance of the multilayer capacitors of Examples 1 to 4 and Comparative Example 2 was higher than the capacitance of the multilayer capacitors of Comparative Example 1, it was evaluated as excellent (described as "◎"), but if the capacitance of the multilayer capacitors of Examples 1 to 4 and Comparative Example 2 was lower than the capacitance of the multilayer capacitors of Comparative Example 1, it was evaluated as insufficient (described as "△"), and the results are shown in Table 1.

[0203] Evaluation Example 5: Evaluation of BDV (breakdown voltage) The BDV (breakdown voltage) was obtained by applying a voltage in a sweep manner from 0 V to 1100 V in 1.00000 V increments using a 2410 model Keithley meter and measuring the voltage when the current reached 20 mA. The BDV was measured in a silicone oil bath.

[0204] After setting the BDV of Comparative Example 1 as a reference value (generally written as "○"), if the BDV of Examples 1 to 4 and Comparative Example 2 was higher than the BDV of Comparative Example 1, it was evaluated as excellent (described as "◎"), and if the BDV of Examples 1 to 4 and Comparative Example 2 was lower than the BDV of Comparative Example 1, it was evaluated as insufficient (described as "△"), and the results are shown in Table 1.

[0205] (Table 1)

[0206] (◎: Excellent ○: General △: Insufficient) Referring to Table 1, compared with the electrode connectivity and capacitance of Comparative Example 1, the multilayer capacitors of Examples 1 to 3 using MAX phase compounds for the internal electrodes to reduce the mismatch between the internal electrodes and the dielectric layer during sintering showed increased electrode connectivity and capacitance.

[0207] In addition, compared with the reliability of Comparative Example 1, the multilayer capacitors of Examples 1 to 3, which include an appropriate content of Sn in the interface portion of the dielectric layer to well bond the dielectric layer and the internal electrode, exhibit improved reliability.

[0208] In addition, compared with the electrical characteristics (e.g., BDV) of Comparative Example 1, the multilayer capacitors of Examples 1 to 3, which do not use a co-material, exhibit improved electrical characteristics (e.g., BDV).

[0209] The multilayer capacitor of Example 4, in which the dielectric grain growth of the dielectric layer is excessively inhibited due to the excessive addition of Sn, exhibits deteriorated electrode connectivity, electrical characteristics, and reliability.

[0210] Compared with the reliability, capacitance, and electrical characteristics (e.g., BDV) of the multilayer capacitor of Comparative Example 1, the multilayer capacitor of Comparative Example 2, in which the dielectric layer and the internal electrode are not well bonded but delaminated due to the absence of Sn in the interface portion of the dielectric layer, exhibits deteriorated reliability, capacitance, and electrical characteristics (e.g., BDV).

[0211] Although the present disclosure has been described in connection with the content of presently considered practical exemplary embodiments, it should be understood that the present disclosure is not limited to the disclosed exemplary embodiments. In contrast, the present disclosure is intended to cover various modifications and equivalent schemes included within the spirit and scope of the appended claims.

Claims

1. A multilayer capacitor, comprising: a capacitor body including a dielectric layer and an inner electrode; and an outer electrode disposed on the capacitor body, wherein the dielectric layer includes a central portion and an interface portion, the interface portion is located on the surface of the central portion and is in contact with the inner electrode, the interface portion of the dielectric layer includes Sn, and the inner electrode includes a first compound represented by Chemical Formula 1: [Chemical Formula 1] M n+1 A 1-x Sn x X n , wherein, in Chemical Formula 1, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, A includes at least one selected from Group 11 elements, Group 12 elements, Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements, X includes C, N, or a combination thereof, 0 < x ≤ 1, and n is an integer from 1 to 4.

2. The multilayer capacitor according to claim 1, wherein M includes Ti, Zr, Hf, Nb, or a combination thereof.

3. The multilayer capacitor according to claim 1, wherein the first compound includes Ti2SnC, Zr2SnC, Nb2SnC, Hf2SnC, Hf2SnN, Ti3SnC2, or a combination thereof.

4. The multilayer capacitor according to claim 1, wherein the Sn content at the interface portion of the dielectric layer is 0.1 at% to 0.5 at%.

5. The multilayer capacitor according to claim 1, wherein the inner electrode includes a central portion and an interface portion, the interface portion of the inner electrode is located on the surface of the central portion of the inner electrode and is in contact with the dielectric layer, the inner electrode further includes a third compound represented by Chemical Formula 3, and the central portion of the inner electrode includes the first compound and the third compound: [Chemical Formula 3] M n+1 X n , wherein, in Chemical Formula 3, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, X includes C, N, or a combination thereof, and n is an integer from 1 to 4.

6. The multilayer capacitor according to claim 5, wherein the inner electrode further includes Sn, and the interface portion of the inner electrode includes Sn and the third compound.

7. The multilayer capacitor according to claim 5, wherein the third compound includes Ti2C, Zr2C, Nb2C, Hf2C, Hf2N, Ti3C2, or a combination thereof.

8. The multilayer capacitor according to claim 6, wherein the Sn content at the interface portion of the inner electrode is 0.01 at% to 0.3 at%.

9. The multilayer capacitor according to claim 1, wherein the interface portion of the dielectric layer further includes a main component and a sub-component, the central portion of the dielectric layer includes the main component and the sub-component, Among them, the main components include: Ba m TiO3, where 0.995 ≤ m ≤ 1.010; (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, where 0.995 ≤ m ≤ 1.010, 0 < x ≤ 0.10; (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20; or a combination thereof.

10. According to the multilayer capacitor described in claim 9, wherein: The secondary components include Dy, Mn, V, Si, Al, Ba, Mg, Sn, Sb, Ge, Ga, In, La, Cr, Hf, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu or a combination thereof.

11. The multilayer capacitor according to claim 1, wherein A is present and includes Al, Ga, In, Tl, Si, Ge, Sn, Pb, Zn, Cd, P, As, S, Cu, Au or a combination thereof.

12. A multilayer capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as an outer electrode, located on the capacitor body, wherein the dielectric layer comprises a central portion and an interface portion, wherein the interface portion is located on a surface of the central portion and contacts the internal electrode, The interface portion of the dielectric layer includes Sn, and The inner electrode includes Sn and a second compound represented by Chemical Formula 2: [Chemical formula 2] M n+1 AX n , Wherein, in Chemical Formula 2, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn or a combination thereof, A includes at least one selected from Group 11 elements, Group 12 elements, Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements, X includes C, N or a combination thereof, and n is an integer of 1 to 4.

13. The multilayer capacitor according to claim 12, wherein The second compound includes Ti2CdC, Sc2InC, Sc2SnC, Ti2AlC, Ti2GaC, Ti2InC, Ti2TlC, V2AlC, V2GaC, Cr2GaC, Ti2AlN, Ti2GaN, Ti2InN, V2GaN, Cr2GaN, Ti2GeC, Ti2SnC, Ti2PbC, V2GeC, Cr2AlC, Cr2GeC, V2PC, V2AsC, Ti2SC, Zr2InC, Zr2TlC, Nb2AlC, Nb2GaC, Nb2InC, Mo2GaC, Zr2InN, Zr2TlN, Zr2SnC, Zr2PbC, Nb2SnC, Nb2PC, Nb2AsC, Zr2SC, Nb2SC, Hf2InC, Hf2TlC, Ta2AlC, Ta2GaC, Hf2SnC, Hf2PbC, Hf2SnN, Hf2SC, Zr2AlC, Ti2ZnC, Ti2ZnN, V2ZnC, Nb2CuC, Mn2GaC, Mo2AuC, Ti2AuN, Ti3AlC2, Ti3GaC2, Ti3InC2, V3AlC2, Ti3SiC2, Ti3GeC2, Ti3SnC2, Ta3AlC2, Ti3ZnC2, Zr3AlC2, Ti4AlN3, V4AlC3, Ti4GaC3, Ti4SiC3, Ti4GeC3, Nb4AlC3, Ta4AlC3, (Mo,V)4AlC3, Mo4VAlC4 or a combination thereof.

14. The multilayer capacitor according to claim 12, wherein: The Sn content of the dielectric layer at the interface portion is 0.1 at % to 0.5 at %.

15. The multilayer capacitor according to claim 12, wherein The inner electrode includes a central portion and an interface portion, the interface portion of the inner electrode being located on a surface of the central portion of the inner electrode and contacting the dielectric layer, The inner electrode further includes a third compound represented by Chemical Formula 3, and The central portion of the inner electrode includes the second compound and the third compound: [Chemical formula 3] M n+1 X n , Among them, in chemical formula 3, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn or a combination thereof, X includes C, N or a combination thereof, and n is an integer of 1 to 4.

16. The multilayer capacitor according to claim 15, wherein The inner electrode further comprises Sn, and The interface portion of the inner electrode includes Sn and the third compound.

17. The multilayer capacitor according to claim 15, wherein The third compound includes Ti2C, Zr2C, Nb2C, Hf2C, Hf2N, Ti3C2 or a combination thereof.

18. The multilayer capacitor according to claim 16, wherein The Sn content at the interface portion of the internal electrode is 0.01 at % to 0.3 at %.

19. The multilayer capacitor according to claim 12, wherein: The interface portion of the dielectric layer further includes a main component and a subcomponent, The central portion of the dielectric layer includes the main component and the auxiliary component, Among them, the main components include: Ba m TiO3, where 0.995 ≤ m ≤ 1.010; (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, where 0.995 ≤ m ≤ 1.010, 0 < x ≤ 0.10; (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20; or a combination thereof.

20. The multilayer capacitor according to claim 19, wherein The secondary components include Dy, Mn, V, Si, Al, Ba, Mg, Sn, Sb, Ge, Ga, In, La, Cr, Hf, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu or a combination thereof.

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