Multilayered capacitor

Abstract

To provide a multilayered capacitor having excellent electrode connectivity and excellent reliability.SOLUTION: A multilayered capacitor according to the present invention includes: a capacitor body which includes a dielectric layer and an internal electrode; and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric crystal grains, and a crystal grain boundary located between at least two of the dielectric crystal grains among the dielectric crystal grains. The crystal grain boundary includes Sn, and the internal electrode includes a compound represented by the chemical formula 1. Definitions of the chemical formula 1 are as described in the specification.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a multilayer capacitor.

Background Art

[0002] Recently, as the multifunctionalization and miniaturization of electronic devices have been rapidly progressing, the miniaturization and performance improvement of electronic components have also been rapidly advanced. In addition, the requirements for high reliability of electrical devices used in automobiles or network devices, etc., and electronic components for industrial use have also greatly increased.

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

[0004] In addition, a multilayer capacitor is a capacitor manufactured in a form in which dielectric layers and internal electrodes are stacked, and is used in various electronic devices such as mobile phones, notebook computers, and LCD TVs.

[0005] Recently, with the development of technology, multilayer capacitors have been required to be miniaturized and have a higher capacitance. For this purpose, technological development has been carried out to enhance the connectivity of the internal electrodes in contact with the dielectric layers to increase the effective electrode area, or to make the dielectric material and the internal electrode material finer.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One embodiment of the present invention provides a multilayer capacitor having excellent electrode connectivity and excellent reliability.

[0007] However, the problems to be solved by the embodiments are not limited to the above-described problems, and can be variously extended within the scope of the technical idea included in the embodiments.

Means for Solving the Problems

[0008] A multilayer capacitor according to an embodiment of the present invention includes a capacitor body including a dielectric layer and internal electrodes, and external electrodes disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric crystal grains; and grain boundaries located between at least two or more of the dielectric crystal grains among the dielectric crystal grains. The grain boundary contains Sn. The internal electrode contains a compound represented by the following Chemical Formula 1.

[0009] [Chemical Formula 1] M n+1 SnX n In Chemical Formula 1, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof. X includes C, N, or a combination thereof. n is an integer from 1 to 4.

[0010] M can include Ti, Zr, Hf, Nb, or a combination thereof.

[0011] The compound represented by Chemical Formula 1 can include Ti2SnC, Zr2SnC, Nb2SnC, Hf2SnC, Hf2SnN, Ti3SnC2, or a combination thereof.

[0012] The content of Sn with respect to the grain boundary can be 0.01 at% to 0.5 at%.

[0013] The dielectric crystal grains include a main component and a sub-component. The main component is Ba m TiO3 (0.995 ≦ m ≦ 1.010), (Ba 1-X Cax ) 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 combinations thereof can be included.

[0014] The secondary component can include dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), magnesium (Mg), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), lanthanum (La), chromium (Cr), hafnium (Hf), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or combinations thereof.

[0015] The average thickness of the internal electrode can be 0.05 μm to 1 μm.

[0016] The average thickness of the dielectric layer can be 0.5 μm to 5 μm.

[0017] A multilayer capacitor according to another embodiment includes a capacitor body including a dielectric layer and an internal electrode, and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric crystallites; and grain boundaries located between at least two or more of the dielectric crystallites. The dielectric crystallites or the grain boundaries include a main component and a secondary component. The grain boundaries further include Sn. The internal electrode includes a compound represented by the following Chemical Formula 1.

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

[0019] The above M can include Ti, Zr, Hf, Nb, or a combination thereof.

[0020] The compound represented by the above Chemical Formula 1 can include Ti2SnC, Zr2SnC, Nb2SnC, Hf2SnC, Hf2SnN, Ti3SnC2, or a combination thereof.

[0021] The content of Sn with respect to the grain boundaries can be 0.01 at% to 0.5 at%.

[0022] The main component is 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, x ≤ 0.10), or a combination thereof.

[0023] The secondary component may include dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), magnesium (Mg), 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] The average thickness of the internal electrode can be 0.05 μm to 1 μm.

[0025] The average thickness of the dielectric layer can be 0.5 μm to 5 μm.

Advantages of the Invention

[0026] The multilayer capacitor according to an embodiment of the present invention has advantages of excellent electrode connectivity and excellent reliability.

[0027] However, the various and beneficial advantages and effects of the present invention are not limited to the above-described content and should be more easily understood in the process of describing specific embodiments of the present invention.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

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

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

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

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

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

[0034] To clearly explain this embodiment, if directions are defined, the L-axis, W-axis, and T-axis shown in the drawings indicate the length direction, width direction, and thickness direction of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) may be a direction perpendicular to the broad surface (main surface) of the sheet-shaped component, and as an example, it can be used as the same concept as the lamination direction in which the dielectric layer 111 is laminated. The length direction (L-axis direction) may be a direction that extends parallel to the broad surface (main surface) of the sheet-shaped component and is substantially perpendicular to the thickness direction (T-axis direction), and as an example, it may be the direction in which the first external electrode 131 and the second external electrode 132 are located on both sides. The width direction (W-axis direction) may be a direction that extends parallel to the broad surface (main surface) of the sheet-shaped component and is substantially perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length of the sheet-shaped component in the length direction (L-axis direction) may be even longer than the length in the width direction (W-axis direction).

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

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

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

[0038] As an example, the first surface, which is the lower surface, may be the surface facing the mounting direction. Also, the first surface to the sixth surface may be flat, but this embodiment is not limited thereto. For example, the first surface to the sixth surface may be a convex curved surface in the central portion, and the corners that are the boundaries of each surface may be rounded.

[0039] The shape, dimensions, and the number of stacked dielectric layers 111 of the capacitor body 110 are not limited to those shown in the drawings of this embodiment.

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

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

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

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

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

[0045] In addition, the capacitor body 110 can further include a side cover region. The side cover region is a margin portion in the width direction and can be respectively disposed on the fifth surface and the sixth surface sides of the active region in the width direction (W-axis direction). Such a side cover region can be formed by applying a conductive paste layer for forming an internal electrode layer only to a partial region of the surface of the dielectric green sheet when applying the conductive paste layer to the surface of the dielectric green sheet, laminating dielectric green sheets without applying the conductive paste layer to both side surfaces of the surface of the dielectric green sheet, and then firing.

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

[0047] Internal electrode The first internal electrode 121 and the second internal electrode 122 are electrodes having different polarities from each other, and are alternately arranged so as to face each other along the T-axis direction with the dielectric layer 111 interposed therebetween, and one end of each is exposed through the third and fourth surfaces of the capacitor body 110.

[0048] The first internal electrode 121 and the second internal electrode 122 can be electrically insulated from each other by a dielectric layer 111 disposed therebetween.

[0049] The ends of the first internal electrode 121 and the second internal electrode 122 that are alternately exposed through the third and fourth surfaces of the capacitor body 110 can be connected to the first external electrode 131 and the second external electrode 132, respectively, and electrically connected.

[0050] In one embodiment, the internal electrodes 121, 122 include a compound represented by the following Chemical Formula 1.

[0051] [Chemical Formula 1] M n+1 SnX n In Chemical Formula 1, 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. As an example, M can include Ti, Zr, Hf, Nb, or a combination thereof.

[0052] The compound represented by Chemical Formula 1 may be a MAX phases compound containing Sn.

[0053] The MAX phase compound is a compound having all the characteristics of metals and ceramics, and is characterized by very excellent electrical conductivity and a low thermal expansion coefficient.

[0054] Since the MAX phase compound has a higher sintering temperature than metals such as Ni, the difference in sintering temperature from the dielectric material of the dielectric layer 111 may not be large. Accordingly, when the internal electrodes 121, 122 containing the MAX phase compound and the dielectric layer 111 are fired together, a mismatching problem does not occur with the dielectric layer 111, so that breakage of the internal electrodes 121, 122 and thickness expansion can be prevented, and electrode connectivity can be significantly improved.

[0055] In addition, in the past, a sintering aid was added during the production of the internal electrodes 121 and 122 in order to reduce the sintering temperature difference between the internal electrodes 121 and 122 and the dielectric layer 111. However, in this case, there was a problem that the sintering aid diffused in the direction of the dielectric layer 111 during the firing process, increasing the thickness of the dielectric layer 111.

[0056] However, when using the MAX phase compound as the material for the internal electrodes 121 and 122, it may not be necessary to use a sintering aid. Therefore, it is possible to prevent the thickness expansion of the dielectric layer 111 and reduce the size of the multilayer capacitor 100 in the T-axis direction (thickness direction).

[0057] In the multilayer capacitor 100 according to one embodiment, by adding the MAX phase compound to the conductive paste for the internal electrodes, the compound represented by Chemical Formula 1 is included in the internal electrodes 121 and 122 after firing, and thus the above-described effects can be obtained.

[0058] As a specific example, the compound represented by Chemical Formula 1 may include Ti2SnC, Zr2SnC, Nb2SnC, Hf2SnC, Hf2SnN, Ti3SnC2, or a combination thereof.

[0059] As an example, the internal electrodes 121 and 122 may further include a conductive metal, and the conductive metal may further include, for example, metals such as Ni, Cu, Ag, Pd, or Au, or alloys thereof, such as an Ag-Pd alloy.

[0060] In addition, the first internal electrode 121 and the second internal electrode 122 may also include dielectric particles of the same composition system as the ceramic material contained in the dielectric layer 111.

[0061] The first internal electrode 121 and the second internal electrode 122 can be formed using a conductive paste containing a conductive metal. As the printing method of the conductive paste, a screen printing method or a gravure printing method can be used.

[0062] As an example, the average thickness of the first internal electrode 121 and the second internal electrode 122 is 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, or 0.25 μm or more, and can be 1 μm or less or 0.5 μm or less.

[0063] The average thickness of the first internal electrodes 121 and 122 can be measured by the following method.

[0064] First, after placing the multilayer capacitor 100 in an epoxy mixture and curing it, the side surfaces of the capacitor body 110 in the L-axis direction and the T-axis direction are polished to the 1 / 2 point in the W-axis direction, fixed, and maintained in a vacuum atmosphere chamber, and a cross-sectional sample (hereinafter referred to as "cross-sectional sample") cut from the center of the capacitor body 110 in the W-axis direction in the L-axis direction and the T-axis direction is prepared.

[0065] In the scanning electron microscope (SEM) image of the cross-sectional sample, taking the central point of the first internal electrode 121 or the second internal electrode 122 in the L-axis direction or the W-axis direction as a reference point, the arithmetic mean value of the thicknesses of the internal electrodes 121 and 122 at 10 points separated from the reference point at a predetermined interval can be obtained, and the average thickness of the internal electrode can be obtained.

[0066] The interval between the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image, and can be, for example, an interval of 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm.

[0067] At this time, all 10 points must be located within the first internal electrode 121 or the second internal electrode 122. If all 10 points are not located within the first internal electrode 121 or the second internal electrode 122, the position of the reference point can be changed, or the interval between the 10 points can be adjusted.

[0068] Dielectric layer In one embodiment, the dielectric layer 111 includes a plurality of dielectric crystallites; and grain boundaries located between at least two or more of the dielectric crystallites, and the grain boundaries contain Sn (tin).

[0069] During the manufacture of the multilayer capacitor 100 according to one embodiment, if a conductive paste for forming an internal electrode layer containing the above-described MAX phase compound containing Sn is applied to a dielectric green sheet and fired, Sn is partially decomposed by the MAX phase compound and can diffuse into the dielectric layer 111. The diffused Sn exists at the dielectric grain boundaries in the dielectric layer 111, which can improve the reliability of the multilayer capacitor 100 by preventing excessive grain growth of the dielectric crystallites.

[0070] The presence and content of Sn contained in the dielectric grain boundaries can be measured by the following method.

[0071] First, observe the cross-sectional sample with a scanning electron microscope (SEM) to prepare an SEM image as shown in FIG. 4. Referring to FIG. 4, by methods such as binarizing the SEM image of the cross-sectional sample, the portions with brightness differences can be distinguished to confirm the grain boundaries that are the boundaries of the dielectric crystallites.

[0072] After that, select an arbitrary grain boundary in the SEM image and perform SEM-EDS analysis at that position to confirm the presence of Sn.

[0073] FIG. 5 is a graph showing the elemental content (atomic %) at positions 1 and 2 in FIG. 4, where (a) shows the elemental content in the dielectric crystallite (position 1 in FIG. 4) and (b) shows the elemental content at the grain boundary (position 2 in FIG. 4).

[0074] Referring to FIG. 5, the elemental content contained in the dielectric crystallite and the grain boundary can be confirmed. Referring to FIG. 5(b), it can be confirmed that Sn is observed at the grain boundary.

[0075] In one embodiment, the content of Sn with respect to the crystal grain boundaries (atomic %; at%) may be 0.01 at% or more, 0.05 at% or more, or 0.1 at% or more, and may be 0.5 at% or less, 0.4 at% or less, or 0.25 at% or less.

[0076] When the content of Sn with respect to the crystal grain boundaries is less than 0.01 at%, Sn is not sufficiently contained in the crystal grain boundaries, and the effect of improving the reliability of the capacitor is negligible. When it exceeds 0.5 at%, the grain growth of the dielectric crystal grains is excessively suppressed.

[0077] The content of Sn with respect to the crystal grain boundaries (at%) may be the arithmetic mean value obtained by selecting three crystal grain boundaries located between different dielectric crystal grains, selecting three equally spaced points at each selected crystal grain boundary, and measuring the content of Sn at a total of nine points.

[0078] The dielectric crystal grains include a main component and a sub-component. In one embodiment, the dielectric crystal grain boundaries may further include a main component and a sub-component.

[0079] The main component is the base material of the dielectric, has a high dielectric constant, and contributes to the formation of the dielectric constant of the multilayer capacitor 100.

[0080] As an example, the main component is 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, 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 containing a combination thereof may be used.

[0081] As a specific example, the main component is 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, x ≤ 0.10), or a dielectric material containing a combination thereof may be used.

[0082] As an example, the main component can 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.

[0083] As an example, the sub-components can 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.

[0084] The dielectric layer 111 can further include a ceramic additive, an organic solvent, a binder, a dispersant, or a combination thereof.

[0085] As an example, the average thickness of the dielectric layer 111 can be 0.5 μm or more, or 1.0 μm or more, and can be 5 μm or less, or 3 μm or less.

[0086] The average thickness of the dielectric layer 111 can be measured by the following method.

[0087] First, prepare a scanning electron microscope (SEM) image obtained by observing a cross-sectional sample with a scanning electron microscope.

[0088] In the scanning electron microscope (SEM) image of the cross-sectional sample, taking the central point in the L-axis direction or the W-axis direction of the dielectric layer 111 as a reference point, the arithmetic mean value of the thickness of the dielectric layer 111 at 10 points separated from the reference point by a predetermined interval can be obtained and used as the average thickness of the dielectric layer 111.

[0089] The interval between the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image. For example, the interval can be 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm.

[0090] At this time, all 10 points must be located within the dielectric layer 111. If all 10 points are not 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.

[0091] External electrode The first external electrode 131 and the second external electrode 132 are provided with voltages of different polarities and are respectively connected to the exposed portions of the first internal electrode 121 and the second internal electrode 122 and can be electrically connected.

[0092] With the above configuration, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charges are accumulated between the first internal electrode 121 and the second internal electrode 122 facing each other. At this time, the capacitance of the multilayer capacitor 100 is proportional to the overlapping area of the first internal electrode 121 and the second internal electrode 122 that overlap each other along the T-axis direction in the active region.

[0093] The first external electrode 131 and the second external electrode 132 are respectively disposed on the third surface and the fourth surface of the capacitor body 110, and include a first connection portion and a second connection portion connected to the first internal electrode 121 and the second internal electrode 122, the third surface and the fourth surface of the capacitor body 110, and a first band portion and a second band portion disposed at the corners where the first surface and the second surface or the fifth surface and the sixth surface are in contact.

[0094] The first band portion and the second band portion are respectively extended from the first connection portion and the second connection portion to a part of the first surface and the second surface or the fifth surface and the sixth surface of the capacitor body 110. The first band portion and the second band portion serve to improve the adhesion strength of the first external electrode 131 and the second external electrode 132.

[0095] As an example, the first external electrode 131 and the second external electrode 132 may each include a sintered metal layer in contact with the capacitor body 110, a conductive resin layer disposed to cover the sintered metal layer, and a plating layer disposed to cover the conductive resin layer.

[0096] The sintered metal layer may include a conductive metal and glass.

[0097] As an example, the sintered metal layer can include copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), alloys thereof, or combinations thereof as the conductive metal. For example, copper (Cu) can include a copper (Cu) alloy. When the conductive metal includes copper, the metal other than copper may be included in an amount of 5 mole parts or less with respect to 100 mole parts of copper.

[0098] As an example, the sintered metal layer can include a composition in which an oxide is mixed as glass. For example, it may be one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide. The transition metal is selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal is selected from the group consisting of lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be one or more selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0099] Optionally, the conductive resin layer is formed on the sintered metal layer. For example, it can be formed in a form that completely covers the sintered metal layer. On the other hand, the first external electrode 131 and the second external electrode 132 may not include the sintered metal layer. In this case, the conductive resin layer may be in direct contact with the capacitor body 110.

[0100] The conductive resin layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110. The length of the region (i.e., the band portion) where the conductive resin layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the band portion) where the sintered metal layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110. That is, the conductive resin layer is formed on the sintered metal layer and can be formed in a form that completely covers the sintered metal layer.

[0101] The conductive resin layer contains a resin and a conductive metal.

[0102] The resin contained in the conductive resin layer has bonding properties and shock absorption properties, and is not particularly limited as long as it can be mixed with the conductive metal powder to form a paste. For example, it can contain a phenolic resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

[0103] The conductive metal contained in the conductive resin layer serves to be electrically connected to the first internal electrode 121 and the second internal electrode 122 or the sintered metal layer.

[0104] The conductive metal contained in the conductive resin layer can have a spherical shape, a flake shape, or a combination of these forms. That is, the conductive metal may consist only of a flake shape or only of a spherical shape, or may be a form in which the flake shape and the spherical shape are mixed.

[0105] Here, the spherical shape can also include a shape that is not a perfect sphere. For example, it can include a shape in which the length ratio of the major axis to the minor axis (major axis / minor axis) is 1.45 or less. The flake-shaped powder means a powder having a flat and elongated shape, and is not particularly limited. For example, the length ratio of the major axis to the minor axis (major axis / minor axis) may be 1.95 or more.

[0106] The first external electrode 131 and the second external electrode 132 can further include a plating layer disposed outside the conductive resin layer.

[0107] The plating layer can include a single metal such as nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb), or an alloy thereof. As an example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be in a form where a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially laminated, or may be in a form where a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer are sequentially laminated. Also, the plating layer can include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0108] The plating layer can improve the mountability with the substrate of the multilayer capacitor 100, structural reliability, durability against the outside, heat resistance, and equivalent series resistance (ESR).

[0109] Manufacturing method of multilayer capacitor The manufacturing method of the multilayer capacitor according to another embodiment includes a step of manufacturing a capacitor body including a dielectric layer and an internal electrode, and a step of forming an external electrode outside the capacitor body.

[0110] First, the manufacturing of the capacitor body will be described.

[0111] In the manufacturing process of the capacitor body, a dielectric paste that becomes a dielectric layer after firing and a conductive paste that becomes an internal electrode after firing are prepared.

[0112] The dielectric paste is manufactured, for example, in the following manner. Dielectric powder is uniformly mixed by means such as wet mixing, dried, and then heat-treated under predetermined conditions to obtain plastic powder. An organic vehicle or an aqueous vehicle is added to the obtained plastic powder and kneaded to prepare a dielectric paste.

[0113] The obtained dielectric paste is formed into a sheet by a technique such as the doctor blade method to obtain a dielectric green sheet. The dielectric paste may also contain additives selected from various dispersants, plasticizers, dielectrics, sub-component compounds, or glass as required.

[0114] The conductive paste for the internal electrode is prepared by kneading the compound represented by the following Chemical Formula 1 with a binder and a solvent.

[0115] [Chemical Formula 1] M n+1 SnX n In the above Chemical Formula 1, M includes Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, X includes C, N, or a combination thereof, n is an integer from 1 to 4.

[0116] Since the compound represented by the above Chemical Formula 1 is as described above, detailed description is omitted here.

[0117] The conductive paste for the internal electrode is applied in a predetermined pattern on the surface of the dielectric green sheet by various printing methods such as screen printing or a transfer method. Then, after laminating the dielectric green sheets with the internal electrode patterns formed thereon in multiple layers, the dielectric green sheet laminate is obtained by pressing in the lamination direction. At this time, the dielectric green sheet and the internal electrode pattern can be laminated so that the dielectric green sheets are located on the upper and lower surfaces in the lamination direction of the dielectric green sheet laminate.

[0118] Optionally, the obtained dielectric green sheet laminate can be cut into a predetermined size by dicing or the like.

[0119] Further, the dielectric green sheet laminate can be solidified and dried to remove a plasticizer or the like as necessary, and can be barrel polished using a horizontal centrifugal barrel polishing machine or the like after solidification and drying. In barrel polishing, the dielectric green sheet laminate is put into a barrel container together with media and a polishing liquid, and rotational motion, vibration, or the like is imparted to the barrel container to polish unnecessary portions such as burrs generated during cutting. Further, after barrel polishing, the dielectric green sheet laminate can be washed with a cleaning liquid such as water and dried.

[0120] The dielectric green sheet laminate is subjected to a debinding process and a firing process to obtain a capacitor body.

[0121] The conditions of the debinding process can be appropriately adjusted according to the main component composition of the dielectric layer and the main component composition of the internal electrode. For example, the heating rate during the debinding process may be 5°C / hour to 300°C / hour, the holding temperature may be 180°C to 400°C, and the temperature holding time may be 0.5 hour to 24 hours. The debinding atmosphere may be air or a reducing atmosphere.

[0122] The conditions of the firing process can be appropriately adjusted according to the main component composition of the dielectric layer and the main component composition of the internal electrode. For example, the temperature during firing may be 1200°C to 1350°C, or 1220°C to 1300°C, and the time may be 0.5 hour to 8 hours, or 1 hour to 3 hours. The firing atmosphere may be a reducing atmosphere, for example, an atmosphere in which a mixed gas of nitrogen gas (N2) and hydrogen gas (H2) is humidified.

[0123] After the firing process, annealing can be performed as necessary. Annealing is a process for re-oxidizing the dielectric layer, and can be performed when the firing process is carried out in a reducing atmosphere. The conditions of the annealing process can also be appropriately adjusted according to the main component composition of the dielectric layer, etc. For example, the temperature during annealing may be 950°C to 1150°C, the time may be 0 hours to 20 hours, and the heating rate may be 50°C / hour to 500°C / hour. The annealing atmosphere may be a humidified nitrogen gas (N2) atmosphere, and the oxygen partial pressure may be 1.0×10 -9 MPa to 1.0×10 -5 MPa.

[0124] In the debinding process, firing process, or annealing process, in order to humidify nitrogen gas, mixed gas, etc., for example, a wetter can be used. In this case, the water temperature may be 5°C to 75°C. The debinding process, firing process, and annealing process can be carried out continuously or independently.

[0125] Optionally, surface treatment such as sandblasting, laser irradiation, or barrel polishing can be performed on the third and fourth surfaces of the obtained capacitor body. By performing such surface treatment, the ends of the first internal electrode and the second internal electrode are exposed on the outermost surfaces of the third and fourth surfaces, whereby the electrical connection between the first external electrode and the second external electrode and the first internal electrode and the second internal electrode becomes good, and an alloy part can be easily formed.

[0126] Thereafter, a sintered metal layer forming paste can be applied to the outer surface of the obtained capacitor body and then sintered to form a sintered metal layer.

[0127] The paste for forming a sintered metal layer can contain a conductive metal and glass. Since the explanations regarding the conductive metal and glass are as described above, repetitive explanations will be omitted. Further, the paste for forming a sintered metal layer can selectively contain sub-components such as a binder, a solvent, a dispersant, a plasticizer, or oxide powder. For example, as the binder, ethyl cellulose, acrylic, or butyral can be used, and as the solvent, organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, or toluene, or aqueous solvents can be used.

[0128] As a method of applying the paste for forming a sintered metal layer to the outer surface of the capacitor body, a dipping method, various printing methods such as screen printing, an application method using a dispenser, or a spraying method using a spray can be used. The paste for the sintered metal layer is applied to at least the third and fourth surfaces of the capacitor body, and can also be selectively applied to a part of the first surface, the second surface, the fifth surface, or the sixth surface where the band portions of the first external electrode and the second external electrode are formed.

[0129] Thereafter, the capacitor body coated with the paste for forming a sintered metal layer is dried and sintered at a temperature of 700°C to 1000°C for 0.1 hour to 3 hours to form a sintered metal layer.

[0130] Optionally, a conductive resin layer can be formed by applying a paste for forming a conductive resin layer to the outer surface of the obtained capacitor body and then curing it.

[0131] The paste for forming a conductive resin layer can contain a resin and, optionally, a conductive metal or a non-conductive filler. Since the descriptions of the conductive metal and the resin are as described above, repetitive descriptions are omitted. Also, the paste for forming a conductive resin layer can optionally contain sub-components such as a binder, a solvent, a dispersant, a plasticizer, or oxide powder. For example, ethyl cellulose, acrylic, or butyral can be used as the binder, and organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, or toluene, or aqueous solvents can be used as the solvent.

[0132] As an example, the method for forming a conductive resin layer can be to dip the capacitor body 110 into the paste for forming a conductive resin layer and then cure it, or to print the paste for forming a conductive resin layer on the surface of the capacitor body 110 by a screen printing method or a gravure printing method, or to apply the paste for forming a conductive resin layer on the surface of the capacitor body 110 and then cure it to form.

[0133] Thereafter, a plating layer is formed outside the conductive resin layer.

[0134] As an example, the plating layer can be formed by a plating method, and can also be formed by sputtering or electroplating.

[0135] Hereinafter, specific embodiments of the invention will be presented. However, the embodiments described below are only for specifically exemplifying or explaining the invention, and the scope of the invention should not be limited thereby.

[0136] [Embodiment] Example 1 A slurry for a dielectric containing BaTiO3 was produced, and a dielectric green sheet was produced using the slurry for a dielectric with an on-roll coater of a head discharge method. Thereafter, a conductive paste for an internal electrode containing Ti2SnC was produced.

[0137] The conductive paste was printed on the surface of the dielectric green sheet, and a dielectric green sheet (width × length × height = 3.2 mm × 2.5 mm × 2.5 mm) with a conductive paste layer formed thereon was laminated and pressed to produce a dielectric green sheet laminate.

[0138] The dielectric green sheet laminate was fired under the conditions of a plasticizing process at 400 °C or lower in a nitrogen atmosphere and a firing temperature of 1300 °C or lower and a hydrogen concentration of 1.0% H2 or lower to produce a multilayer capacitor according to Example 1.

[0139] After the multilayer capacitor according to Example 1 was placed in an epoxy mixture and cured, the side surfaces in the L-axis direction and the T-axis direction of the capacitor body were polished to the 1 / 2 point in the W-axis direction, and after fixing, it was maintained in a vacuum atmosphere chamber, and cross-sectional samples cut in the L-axis direction and the T-axis direction from the center in the W-axis direction of the capacitor body were prepared. Thereafter, the cross-sectional samples were observed with a scanning electron microscope (SEM) and subjected to SEM-EDS analysis, and it was confirmed that Sn was observed at the dielectric crystal grain boundaries.

[0140] Comparative Example 1 A multilayer capacitor according to Comparative Example 1 was produced in the same manner as in Example 1, except that a capacitor was produced using Ni and a sintering aid (BaTiO3) instead of Ti2SnC in the conductive paste for the internal electrode.

[0141] Comparative Example 2 A multilayer capacitor according to Comparative Example 2 was produced in the same manner as in Example 1, except that a capacitor was produced using Ti3AlC2 instead of Ti2SnC in the conductive paste for the internal electrode.

[0142] (Evaluation Example) Evaluation Example 1: Size evaluation in the T-axis direction The sizes in the T-axis direction of the multilayer capacitors according to Example 1, Comparative Example 1, and Comparative Example 2 were measured.

[0143] The capacitor thickness from the center in the L-axis direction to the T-axis direction of the multilayer capacitor was measured using a vernier caliper. The thickness in the T-axis direction was measured for 50 multilayer capacitors, and the arithmetic mean was derived.

[0144] Taking the value of Comparative Example 1 as 100%, the values of Example 1 and Comparative Example 2 were converted into relative ratios (%), and the results are shown in Table 1 below.

[0145] Evaluation Example 2: Reliability (MTTF) Evaluation The reliability (MTTF, Mean Time To Failure) of the multilayer capacitors according to Example 1, Comparative Example 1, and Comparative Example 2 was evaluated.

[0146] Four hundred samples of the multilayer capacitors according to Example 1, Comparative Example 1, and Comparative Example 2 were prepared each, and a high-temperature load test was performed on them under the conditions of 125°C and 8V. The time when the insulation resistance became 10 kΩ or less was taken as the failure time.

[0147] The MTTF values for 400 samples were derived. Taking the MTTF value of Comparative Example 1 as the reference value (100%), the MTTF values of Example 1 and Comparative Example 2 were expressed as relative ratios.

[0148] When it is 80 - 90% of the value of Comparative Example 1, it is marked as "△", when it is 90 - 100%, it is marked as "○", and when it is 100 - 110%, it is marked as "◎" and shown in Table 1 below.

[0149] [Table 1]

[0150] Referring to Table 1, it can be confirmed that the multilayer capacitor of Example 1 containing Ti2SnC, which is a MAX phase compound containing Sn, can prevent the dielectric layer from becoming thick, and the size in the T-axis direction (thickness direction) is relatively small.

[0151] In addition, it can be confirmed that Sn contained in Ti2SnC moves to the grain boundaries of the dielectric layer during the firing process, and the reliability of the capacitor is also extremely excellent.

[0152] On the contrary, it can be confirmed that the laminated capacitor of Comparative Example 1 in which the internal electrode was manufactured by including Ni and a sintering aid as in the past without using the MAX phase compound has a relatively large size in the T-axis direction (thickness direction).

[0153] In addition, for the laminated capacitor of Comparative Example 2 in which the internal electrode was manufactured by including a MAX phase compound not containing Sn, since Sn does not exist at the grain boundaries of the dielectric layer, it can be confirmed that the reliability has deteriorated.

[0154] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to this, and it can be variously modified and implemented within the scope of the claims, the detailed description of the invention, and the attached drawings. Naturally, this also belongs to the scope of the present invention.

Explanation of Reference Numerals

[0155] 100: Laminated capacitor 110: Capacitor body 111: Dielectric layer 112, 113: Cover region 121: First internal electrode 122: Second internal electrode 131: First external electrode 132: Second external electrode

Claims

1. A multilayer capacitor including a capacitor body including a dielectric layer and internal electrodes, and external electrodes disposed outside the capacitor body, wherein the dielectric layer includes a plurality of dielectric crystallites and grain boundaries located between at least two of the dielectric crystallites, the grain boundaries contain Sn, and the internal electrodes contain a compound represented by the following Chemical Formula 1: 【Chemical Formula 1】 M ｎ＋１ SnX ｎ In Chemical Formula 1, 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.

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

3. The compound represented by the chemical formula 1 is Ti ２ SnC, Zr ２ SnC, Nb ２ SnC, Hf ２ SnC, Hf ２ SnN, Ti ３ SnC ２ , or a combination thereof, the multilayer capacitor according to claim 1.

4. The multilayer capacitor according to Claim 1, wherein the content of Sn with respect to the grain boundaries is 0.01 at% or more and 0.5 at% or less.

5. The dielectric crystallites include a main component and a sub-component, The main component is Ba ｍ TiO ３ (0.995 ≤ m ≤ 1.010), (Ba １－Ｘ Ca ｘ ) ｍ (Ti １－ｙ Zr ｙ )O ３ (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba ｍ (Ti １－ｘ Zr ｘ )O ３ (0.995 ≤ m ≤ 1.010, x ≤ 0.10), or a combination thereof, the multilayer capacitor according to claim 1.

6. The sub-component includes dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), magnesium (Mg), 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. The multilayer capacitor according to Claim 5.

7. The multilayer capacitor according to Claim 1, wherein the average thickness of the internal electrodes is 0.05 μm or more and 1 μm or less.

8. The multilayer capacitor according to Claim 1, wherein the average thickness of the dielectric layer is 0.5 μm or more and 5 μm or less.

9. A multilayer capacitor including a capacitor body including a dielectric layer and internal electrodes, and external electrodes disposed outside the capacitor body, wherein the dielectric layer includes a plurality of dielectric crystallites and grain boundaries located between at least two of the dielectric crystallites, The dielectric crystal grains or the grain boundaries contain a main component and a sub-component, the grain boundaries further contain Sn, the internal electrode contains a compound represented by the following Chemical Formula 1, multilayer capacitor: [Chemical Formula 1] M ｎ＋１ SnX ｎ In Chemical Formula 1, M contains Ti, Zr, Hf, Sc, Cr, V, Nb, Ta, Mo, Mn, or a combination thereof, X contains C, N, or a combination thereof, n is an integer from 1 to 4.

10. The multilayer capacitor according to Claim 9, wherein the M contains Ti, Zr, Hf, Nb, or a combination thereof.

11. The compound represented by the chemical formula 1 is Ti ２ SnC, Zr ２ SnC, Nb ２ SnC, Hf ２ SnC, Hf ２ SnN, Ti ３ SnC ２ or a combination thereof, the multilayer capacitor according to claim 9.

12. The multilayer capacitor according to Claim 9, wherein the content of Sn with respect to the grain boundaries is 0.01 at% or more and 0.5 at% or less.

13. The main component is Ba ｍ TiO ３ (0.995 ≤ m ≤ 1.010), (Ba １－Ｘ Ca ｘ ) ｍ (Ti １－ｙ Zr ｙ )O ３ (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba ｍ (Ti １－ｘ Zr ｘ )O ３ (0.995 ≤ m ≤ 1.010, x ≤ 0.10), or a combination thereof, the multilayer capacitor according to claim 9.

14. The sub-component contains dysprosium (Dy), manganese (Mn), vanadium (V), silicon (Si), aluminum (Al), barium (Ba), magnesium (Mg), 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, the multilayer capacitor according to Claim 9.

15. The multilayer capacitor according to Claim 9, wherein the average thickness of the internal electrode is 0.05 μm or more and 1 μm or less.

16. The multilayer capacitor according to Claim 9, wherein the average thickness of the dielectric layer is 0.5 μm or more and 5 μm or less.

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