Multilayer ceramic capacitor and method of preparing the same

Abstract

To provide a multilayer ceramic capacitor that has excellent connectivity between the internal and external electrodes and has excellent moisture resistance reliability, and a method of preparing the same.SOLUTION: A multilayer ceramic capacitor includes a capacitor body including a dielectric layer and an internal electrode layer, and an external electrode disposed on the outside of the capacitor body, the external electrode includes an electrode layer directly located on a cross section of the capacitor body in such a way as to be electrically connected with at least one of the internal electrode layers, the electrode layer includes a conductive metal and glass including cobalt (Co), the cobalt (Co) is included in an amount of 0.13 parts by weight to 0.64 parts by weight based on 100 parts by weight of the conductive metal.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic capacitor and a method for manufacturing the same.

Background Art

[0002] Examples of electronic components using ceramic materials include capacitors, inductors, piezoelectric elements, varistors, or thermistors. Among such ceramic electronic components, a multilayer ceramic capacitor (MLCC) can be used in various electronic devices due to its advantages of being small in size, ensuring high capacitance, and being easy to mount.

[0003] For example, a multilayer ceramic capacitor can be used as a chip-shaped capacitor mounted on the substrate of various electronic products such as video devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), organic light-emitting diodes (OLEDs), computers, personal mobile terminals, and smartphones to charge or discharge electricity.

[0004] Recently, with the miniaturization of electronic products, multilayer ceramic capacitors are also required to be ultra-miniaturized and have ultra-high capacitance. For this purpose, multilayer ceramic capacitors having a structure in which the thicknesses of the dielectric layer and the internal electrode layer are reduced and a larger number of dielectric layers and internal electrode layers are laminated have been manufactured. Such ultra-small and ultra-high-capacitance multilayer ceramic capacitors are recently used in fields that require a high level of reliability such as electric vehicles, so there is a situation where high reliability suitable for this is required.

Summary of the Invention

Problems to be Solved by the Invention

[0005] One embodiment provides a multilayer ceramic capacitor that is excellent not only in the connectivity between the internal electrodes and the external electrodes but also in moisture resistance reliability.

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

Means for Solving the Problems

[0007] One embodiment includes a capacitor body including a dielectric layer and an internal electrode layer, and an external electrode disposed outside the capacitor body. The external electrode includes an electrode layer directly located on the cross-section of the capacitor body so as to be electrically connected to at least one of the internal electrode layers. The electrode layer includes a conductive metal and a glass containing cobalt (Co). The cobalt (Co) is contained in an amount of 0.13 parts by weight to 0.64 parts by weight with respect to 100 parts by weight of the conductive metal, providing a multilayer ceramic capacitor.

[0008] The cobalt (Co) may be included in a region near the interface, which is defined as a region from the interface between the electrode layer of the external electrode and the internal electrode layer to a point in the longitudinal direction (L axis) that is 5% to 15% of the total thickness of the external electrode.

[0009] The glass may further contain iron (Fe).

[0010] The iron (Fe) may be contained in an amount of 0.18 parts by weight to 0.91 parts by weight with respect to 100 parts by weight of the conductive metal.

[0011] The iron (Fe) may be included in a region near the interface, which is defined as a region from the interface between the electrode layer of the external electrode and the internal electrode layer to a point in the longitudinal direction (L axis) that is 5% to 15% of the total thickness of the external electrode.

[0012] The glass can further contain lithium (Li), potassium (K), silicon (Si), aluminum (Al), nickel (Ni), silver (Ag), sodium (Na), barium (Ba), calcium (Ca), strontium (Sr), boron (B), zinc (Zn), tin (Sn), copper (Cu), indium (In), titanium (Ti), phosphorus (P), manganese (Mn), germanium (Ge), or a combination thereof.

[0013] Based on the total amount of the glass, the lithium (Li) may be contained in an amount of 5 wt% to 20 wt%, the potassium (K) may be contained in an amount of 5 wt% to 20 wt%, the silicon (Si) may be contained in an amount of 5 wt% to 20 wt%, the aluminum (Al) may be contained in an amount of 5 wt% to 15 wt%, the nickel (Ni) may be contained in an amount of 0.01 wt% to 20 wt%, the silver (Ag) may be contained in an amount of 0.01 wt% to 15 wt%, the sodium (Na) may be contained in an amount of 0.01 wt% to 25 wt%, the barium (Ba) may be contained in an amount of 15 wt% to 45 wt%, the calcium (Ca) may be contained in an amount of 15 wt% to 45 wt%, the strontium (Sr) may be contained in an amount of 15 wt% to 45 wt%, the boron (B) may be contained in an amount of 15 wt% to 25 wt%, the zinc (Zn) may be contained in an amount of 1 wt% to 15 wt%, the tin (Sn) may be contained in an amount of 0.01 wt% to 15 wt%, the copper (Cu) may be contained in an amount of 0.01 wt% to 15 wt%, the indium (In) may be contained in an amount of 0.01 wt% to 15 wt%, the titanium (Ti) may be contained in an amount of 0.01 wt% to 15 wt%, the phosphorus (P) may be contained in an amount of 0.01 wt% to 15 wt%, the manganese (Mn) may be contained in an amount of 0.01 wt% to 15 wt%, and the germanium (Ge) may be contained in an amount of 0.01 wt% to 15 wt%.

[0014] The glass may be contained in an amount of 1 part by weight to 40 parts by weight based on 100 parts by weight of the conductive metal.

[0015] The average particle size (D50) of the glass may be 0.1 μm to 5 μm.

[0016] The conductive metal 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.

[0017] Another embodiment includes the steps of applying a paste for forming an electrode layer including a conductive metal and a glass composition on one surface of a capacitor body including a dielectric layer and an internal electrode layer; and sintering the paste for forming the electrode layer to form an electrode layer of an external electrode, wherein the glass composition includes cobalt oxide (CoO) in an amount of 0.13 to 0.64 parts by weight based on 100 parts by weight of the conductive metal, and provides a method for manufacturing a multilayer ceramic capacitor.

[0018] The sintering can be performed at a temperature of 400°C to 850°C.

[0019] The glass composition can further include iron oxide, and the iron oxide can include FeO, Fe2O3, Fe3O4, or combinations thereof.

[0020] The iron oxide may be included in an amount of 0.18 to 0.91 parts by weight based on 100 parts by weight of the conductive metal.

[0021] The glass composition can further include lithium oxide (Li2O); potassium oxide (K2O); silicon dioxide (SiO2); aluminum oxide (Al2O3); nickel oxide (NiO); silver oxide (Ag2O); sodium oxide (NaO); barium oxide (BaO); calcium oxide (CaO); strontium oxide (SrO); boron oxide (B2O3); zinc oxide (ZnO); tin oxide including SnO, SnO2, or a combination thereof; copper oxide including Cu2O, CuO, or a combination thereof; indium oxide (In2O3); titanium dioxide (TiO2); phosphorus pentoxide (P2O5); manganese oxide including MnO, Mn2O, Mn2O3, Mn3O4, or a combination thereof; germanium oxide (GeO2) or a combination thereof.

[0022] With respect to the total amount of the glass composition, the lithium oxide (Li2O) may be contained in an amount of 5 wt% to 20 wt%, the potassium oxide (K2O) may be contained in an amount of 5 wt% to 20 wt%, the silicon dioxide (SiO2) may be contained in an amount of 5 wt% to 20 wt%, the aluminum oxide (Al2O3) may be contained in an amount of 5 wt% to 15 wt%, the nickel oxide (NiO) may be contained in an amount of 0.01 wt% to 20 wt%, the silver oxide (Ag2O) may be contained in an amount of 0.01 wt% to 15 wt%, the sodium oxide (NaO) may be contained in an amount of 0.01 wt% to 25 wt%, the barium oxide (BaO) may be contained in an amount of 15 wt% to 45 wt%, the calcium oxide (CaO) may be contained in an amount of 15 wt% to 45 wt%, the strontium oxide (SrO) may be contained in an amount of 15 wt% to 45 wt%, the boron oxide (B2O3) may be contained in an amount of 15 wt% to 25 wt%, the zinc oxide (ZnO) may be contained in an amount of 1 wt% to 15 wt%, the tin oxide may be contained in an amount of 0.01 wt% to 15 wt%, the copper oxide may be contained in an amount of 0.01 wt% to 15 wt%, the indium oxide (In2O3) may be contained in an amount of 0.01 wt% to 15 wt%, the titanium dioxide (TiO2) may be contained in an amount of 0.01 wt% to 15 wt%, the phosphorus pentoxide (P2O5) may be contained in an amount of 0.01 wt% to 15 wt%, the manganese oxide may be contained in an amount of 0.01 wt% to 15 wt%, and the germanium oxide (GeO2) may be contained in an amount of 0.01 wt% to 15 wt%.

[0023] The glass composition may be contained in an amount of 1 part by weight to 40 parts by weight with respect to 100 parts by weight of the conductive metal.

[0024] The conductive metal 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.

Advantages of the Invention

[0025] The multilayer ceramic capacitor according to one embodiment can improve moisture resistance reliability by including an external electrode having excellent connectivity with the internal electrode layer.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0027] Hereinafter, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it with reference to the attached drawings. In order to clearly explain the present invention in the drawings, parts unnecessary for the explanation are omitted, and the same reference numerals are given to the same or similar components throughout the specification. Also, in the attached drawings, some components are exaggerated, omitted, or schematically illustrated, and the sizes of the components do not fully reflect the actual sizes.

[0028] 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, and alternatives included in the idea and technical scope of the present invention are included.

[0029] Terms including ordinal numbers such as first, second, etc. can be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0030] Also, when a part such as a layer, film, region, plate, etc. is "on" or "above" another part, this includes not only the case where it is directly above the other part, but also the case where there are other parts in between. Conversely, when a part is "directly above" another part, it means that there are no other parts in between. Also, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" in the direction opposite to gravity.

[0031] 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 understood 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 include other components rather than excluding other components unless otherwise stated to the contrary.

[0032] Also, throughout the specification, when "on a plane" is mentioned, this means when the target part is viewed from above, and when "in a cross-section" is mentioned, this means when the cross-section obtained by vertically cutting the target part is viewed from the side.

[0033] Also, throughout the specification, when "connected" is mentioned, it does not only mean that two or more components are directly connected. Instead, it can mean that two or more components are indirectly connected through other components, not only physically connected but also electrically connected, or components that are named differently depending on their position or function but can be considered integral.

[0034] Hereinafter, a multilayer ceramic capacitor according to an embodiment will be described with reference to FIGS. 1 to 3.

[0035] FIG. 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment, FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor cut along line I-I' of FIG. 1, and FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor cut along line II-II' of FIG. 1.

[0036] The L-axis, W-axis, and T-axis shown in FIGS. 1 to 3 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 stacking direction in which the dielectric layer 111 is stacked. 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 longer than the length in the width direction (W-axis direction).

[0037] Referring to FIGS. 1 to 3, a multilayer ceramic capacitor 100 according to an embodiment includes a capacitor body 110 and external electrodes 131 and 132 disposed outside the capacitor body 110. The external electrodes 131 and 132 can include 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.

[0038] 〔Capacitor Body〕 The capacitor body 110 may, for example, have a roughly hexahedral shape.

[0039] For the convenience of explanation of an embodiment, 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 of the capacitor body 110 facing each other in the length direction (L-axis direction) and connected to the first surface and the second surface are defined as a third surface and a fourth surface, and both surfaces of the capacitor body 110 facing each other in the width direction (W-axis direction) and connected to the first surface and the second surface and the third surface and the fourth surface are defined as a fifth surface and a sixth surface.

[0040] As an example, the first surface, which is the lower surface, can be the surface facing the mounting direction. Also, the first surface to the sixth surface may be flat, but the embodiment is not limited thereto. For example, the first surface to the sixth surface may be a convex curved surface at the center, and the corners, which are the boundaries of each surface, may be rounded.

[0041] The shape, dimensions, and number of stacked dielectric layers 111 of the capacitor body 110 are not limited to those shown in the drawings of this embodiment.

[0042] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrode layers 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and a first internal electrode 121 and a second internal electrode 122 alternately arranged in the thickness direction (T-axis direction) with the dielectric layers 111 interposed therebetween.

[0043] At this time, the boundaries between the respective dielectric layers 111 of the capacitor body 110 adjacent to each other can be integrated to such an extent that they are difficult to confirm without using a scanning electron microscope (SEM).

[0044] The capacitor body 110 can include an active region. The active region is a portion 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 121 or the second internal electrode 122 laminated along the thickness direction (T-axis direction) overlaps.

[0045] In addition, the capacitor body 110 can further include a cover region and a side margin region.

[0046] The cover region is a margin portion in the thickness direction and can be disposed on the first surface side and the second surface side of the active region in the thickness direction (T-axis direction), respectively. Such a cover region may be a single dielectric layer 111 or two or more dielectric layers 111 laminated on the upper surface and the lower surface of the active region, respectively.

[0047] The side margin region is a margin portion in the width direction and can be disposed on the fifth surface side and the sixth surface side of the active region in the width direction (W-axis direction), respectively. Such a side margin region can be formed by applying a conductive paste layer for the internal electrode 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.

[0048] The cover region and the side margin region serve to prevent damage to the first internal electrode 121 and the second internal electrode 122 due to physical or chemical stress.

[0049] The dielectric layer 111 mainly contains a barium titanate-based compound.

[0050] The barium titanate-based compound is a dielectric base material, has a high dielectric constant, and contributes to the formation of the dielectric constant of the multilayer ceramic capacitor 100.

[0051] The barium titanate-based compound can include, for example, 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 combinations thereof.

[0052] The dielectric layer 111 can further include a sub-component. The sub-component can further include, for example, manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), vanadium (V), or combinations thereof.

[0053] The average thickness (average length in the T-axis direction) of the dielectric layer 111 may be 2.0 μm to 8.0 μm, for example, 2.4 μm to 7.8 μm. When the average thickness of the dielectric layer 111 is within the above range, the reliability of the multilayer ceramic capacitor is excellent. This is based on the scanning electron microscope (SEM) image of the cross-sectional sample measured as described above. Taking the central point in the length direction (L-axis direction) or width direction (W-axis direction) of the dielectric layer 111 as the reference point, it can be obtained as the arithmetic mean value of the thickness of the dielectric layer 111 at 10 points separated by a predetermined interval from the reference point. The interval between the 10 points can be adjusted according to the scale of the scanning electron microscope (SEM) image, for example, an interval of 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm. At this time, all 10 points must be located within the 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.

[0054] The internal electrode layers 121 and 122, that is, 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 is exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0055] The first internal electrode 121 and the second internal electrode 122 can be electrically insulated from each other by the dielectric layer 111 disposed in the middle.

[0056] The ends of the first internal electrode 121 and the second internal electrode 122 alternately exposed through the third surface and the fourth surface of the capacitor body 110 are respectively connected to the first external electrode 131 and the second external electrode 132 and can be electrically connected.

[0057] The first internal electrode 121 and the second internal electrode 122 contain a conductive metal, for example, a metal such as Ni, Cu, Ag, Pd, Au, or an alloy thereof, for example, an Ag-Pd alloy.

[0058] Further, the first internal electrode 121 and the second internal electrode 122 may contain dielectric particles of the same composition system as the ceramic material contained in the dielectric layer 111.

[0059] 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.

[0060] The average thickness of the first internal electrode 121 and the second internal electrode 122 may be 0.1 μm to 2 μm. The average thickness of the first internal electrode 121 and the second internal electrode 122 can be measured by scanning electron microscope (SEM) analysis. Here, since the scanning electron microscope (SEM) analysis is the same as the method for measuring the average thickness of the dielectric layer 111 described above, the description thereof is omitted.

[0061] The capacitor body 110 can be formed by firing a laminate in which a plurality of dielectric layers 111 and internal electrode layers 121 and 122 are laminated.

[0062] 〔External electrodes〕 Referring to FIG. 2, the external electrodes 131 and 132, that is, 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.

[0063] 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 ceramic capacitor 100 becomes proportional to the overlapping area of the first internal electrode 121 and the second internal electrode 122 that overlap each other along the T-axis direction in the active region.

[0064] 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 are connected to the first internal electrode 121 and the second internal electrode 122, and include first connection portions and second connection portions, the third surface and the fourth surface of the capacitor body 110, and first band portions and second band portions disposed at corners where the first surface and the second surface or the fifth surface and the sixth surface are in contact, respectively.

[0065] 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 can play a role in improving the adhesion strength of the first external electrode 131 and the second external electrode 132.

[0066] The external electrodes 131, 132 include electrode layers 10, 20 located on the cross-section of the capacitor body 110 so as to be electrically connected to at least one of the internal electrode layers 121, 122. Specifically, the first external electrode 131 includes a first electrode layer 10 directly located on the cross-section of the capacitor body 110 so as to be electrically connected to the first internal electrode 121. Also, the second external electrode 132 includes a second electrode layer 20 directly located on the cross-section of the capacitor body 110 so as to be electrically connected to the second internal electrode 122.

[0067] The electrode layers 10, 20 can include a conductive metal and glass.

[0068] The conductive metal 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. Among these, the conductive metal can include, for example, copper (Cu) or a copper (Cu) alloy.

[0069] The conductive metal may be in powder form. Also, the conductive metal can have a spherical or flake form. The size (D50) of the spherical conductive metal may be 0.1 μm to 5 μm, for example, 0.5 μm to 3 μm. The size of the flake-shaped conductive metal may be 1 μm to 20 μm based on the major axis, for example, 5 μm to 15 μm. The size (D50) of the conductive metal can be calculated by measuring the major axis of at least 100 conductive metal particles in a scanning electron microscope (SEM) image of a cross-sectional sample, creating a size distribution cumulative curve, and calculating D50. D50 means the size at the point where it becomes 50% in the size distribution cumulative curve.

[0070] The glass can contain cobalt (Co).

[0071] In the manufacturing process of the capacitor body 110, specifically, in the process of firing a dielectric green sheet laminate in which a dielectric layer 111 made of a barium titanate-based compound and internal electrode layers 121, 122 made of nickel (Ni) are alternately laminated, firing is performed under relatively weak reduction conditions to prevent deterioration of the characteristics of the dielectric green sheet laminate. In the capacitor body 110 formed after the firing is completed, a shape appears in which the terminals of the internal electrode layers 121, 122 made of nickel (Ni) are oxidized as nickel oxide (NiO). According to one embodiment, when the electrode layers 10, 20 of the external electrodes 131, 132 contain a cobalt (Co) component, during the heat treatment in the sintering process when manufacturing the external electrodes, the reduction behavior of nickel oxide (NiO) is promoted at the surface where the external electrodes 131, 132 are in contact with the internal electrode layers 121, 122, that is, the reaction to reduce nickel oxide (NiO) can be promoted. From this, a Cu-Ni alloy is formed, and the connectivity between the external electrode and the internal electrode layer can be improved. Moreover, by improving the connectivity between the external electrode and the internal electrode layer due to the formation of the Cu-Ni alloy, the capacitance variation characteristics can be improved and the equivalent series resistance (ESR) value can be lowered. Thereby, the moisture resistance reliability of the multilayer ceramic capacitor can be improved.

[0072] Cobalt (Co) may be contained in an amount of 0.13 to 0.64 parts by weight, for example, 0.133 to 0.636 parts by weight, based on 100 parts by weight of the conductive metal. When cobalt (Co) as a glass component is contained within the above content range in the electrode layers 10 and 20, the reduction behavior of nickel oxide (NiO) is promoted during the heat treatment in the firing process at the surfaces where the external electrodes 131 and 132 are in contact with the internal electrode layers 121 and 122, and the formation of the Cu-Ni alloy can be improved. As a result, the connectivity between the external electrode and the internal electrode layer is improved, and a laminated ceramic capacitor excellent in moisture resistance reliability can be ensured.

[0073] As an example, cobalt (Co) may be present in a region within the electrode layers 10 and 20 that is close to the interface between the electrode layers 10 and 20 and the internal electrode layers 121 and 122, that is, in the vicinity region R of the interface. Specifically, the vicinity region R of the interface can be defined as the region from the interface between the electrode layers 10 and 20 of the external electrodes 131 and 132 and the internal electrode layers 121 and 122 to the point that is 5% to 15% of the total thickness of the external electrode in the length direction (L axis).

[0074] When cobalt (Co) is mainly contained in the vicinity region R of the interface, the reduction reaction of nickel oxide (NiO) formed at the surfaces where the external electrodes 131 and 132 are in contact with the internal electrode layers 121 and 122 is promoted, and the formation of the Cu-Ni alloy can be facilitated. As a result, the connectivity between the external electrode and the internal electrode layer can be improved.

[0075] The glass may further contain iron (Fe). When the glass contains both cobalt (Co) and iron (Fe), the promotion of the reduction reaction of nickel oxide (NiO) during firing can be increased. As a result, the formation of the Cu-Ni alloy becomes easy and the connectivity between the external electrode and the internal electrode layer can be increased.

[0076] Iron (Fe) may be contained in an amount of 0.18 to 0.91 parts by weight, for example, 0.189 to 0.905 parts by weight, based on 100 parts by weight of the conductive metal. When iron (Fe) as a glass component is contained within the above content range in the electrode layers 10 and 20, Cu-Ni alloy formation is facilitated after sintering in the external electrode formation process, thereby improving the connectivity between the external electrode and the internal electrode layer.

[0077] As an example, iron (Fe) may be present in a region within the electrode layers 10 and 20 that is close to the interface between the electrode layers 10 and 20 and the internal electrode layers 121 and 122, i.e., the interface vicinity region R defined above. When iron (Fe) is mainly contained in the interface vicinity region R, the reduction reaction of nickel oxide (NiO) can be promoted and Cu-Ni alloy formation can be facilitated. Thereby, the connectivity between the external electrode and the internal electrode layer can be improved.

[0078] In addition to cobalt (Co) and iron (Fe), the glass may further contain lithium (Li), potassium (K), silicon (Si), aluminum (Al), nickel (Ni), silver (Ag), sodium (Na), barium (Ba), calcium (Ca), strontium (Sr), boron (B), zinc (Zn), tin (Sn), copper (Cu), indium (In), titanium (Ti), phosphorus (P), manganese (Mn), germanium (Ge), or combinations thereof.

[0079] Lithium (Li) may be contained in an amount of 5 wt% to 20 wt%, for example 7 wt% to 17 wt%, based on the total amount of the glass. Potassium (K) may be contained in an amount of 5 wt% to 20 wt%, for example 7 wt% to 17 wt%, based on the total amount of the glass. Silicon (Si) may be contained in an amount of 5 wt% to 20 wt%, for example 7 wt% to 17 wt%, based on the total amount of the glass. Aluminum (Al) may be contained in an amount of 5 wt% to 15 wt%, for example 7 wt% to 13 wt%, based on the total amount of the glass. Nickel (Ni) may be contained in an amount of 0.01 wt% to 20 wt%, for example 0.1 wt% to 15 wt%, based on the total amount of the glass. Silver (Ag) may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass. Sodium (Na) may be contained in an amount of 0.01 wt% to 25 wt%, for example 0.1 wt% to 20 wt%, based on the total amount of the glass. Barium (Ba) may be contained in an amount of 15 wt% to 45 wt%, for example 20 wt% to 40 wt%, based on the total amount of the glass. Calcium (Ca) may be contained in an amount of 15 wt% to 45 wt%, for example 20 wt% to 40 wt%, based on the total amount of the glass. Strontium (Sr) may be contained in an amount of 15 wt% to 45 wt%, for example 20 wt% to 40 wt%, based on the total amount of the glass. Boron (B) may be contained in an amount of 15 wt% to 25 wt%, for example 17 wt% to 23 wt%, based on the total amount of the glass. Zinc (Zn) may be contained in an amount of 1 wt% to 15 wt%, for example 3 wt% to 13 wt%, based on the total amount of the glass. Tin (Sn) may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass. Copper (Cu) may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass. Indium (In) may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass. Titanium (Ti) may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass.Phosphorus (P) may be contained in an amount of 0.01 wt% to 15 wt%, for example, 0.1 wt% to 10 wt%, based on the total amount of the glass. Manganese (Mn) may be contained in an amount of 0.01 wt% to 15 wt%, for example, 0.1 wt% to 10 wt%, based on the total amount of the glass. Germanium (Ge) may be contained in an amount of 0.01 wt% to 15 wt%, for example, 0.1 wt% to 10 wt%, based on the total amount of the glass. When the above components are contained within the above content ranges as glass components, the formation of a Cu-Ni alloy after sintering becomes easy during the external electrode formation process, and the connectivity between the external electrode and the internal electrode layer can be improved.

[0080] The above-described glass components contained in the electrode layers 10 and 20 can be confirmed through SEM (scanning electron microscope) analysis and EPMA (electron probe microanalyzer) mapping.

[0081] The SEM analysis can be measured by the following method. After laying the multilayer ceramic capacitor 100 horizontally, the periphery of the multilayer ceramic capacitor 100 is fixed with an epoxy resin and polished with a polishing machine to obtain a cross-sectional sample having an LT plane so that the capacitor body 110 and the external electrodes 131 and 132 can be observed. Next, the obtained cross-sectional sample can be measured with a scanning electron microscope (SEM). The SEM can be measured, for example, using TESCAN SOLARIS X under the conditions of 5 keV and 300 pA in a region of approximately 55 μm × 50 μm in width × length so that the surfaces where the internal electrode layers 121 and 122 of the capacitor body 110 are in contact with the external electrodes 131 and 132 can be seen.

[0082] In addition, EPMA (electron probe microanalyzer) mapping can be analyzed by the following method. First, a cross-sectional sample can be obtained from the multilayer ceramic capacitor 100 by the aforementioned method. For the obtained cross-sectional sample, EPMA (electron probe microanalyzer) analysis is measured to confirm the mapping of each element present in the electrode layer of the external electrode and the elemental content.

[0083] It can be confirmed through EPMA analysis that cobalt (Co) and iron (Fe) components are observed in the glass matrix. From this, it can be seen that cobalt (Co) and iron (Fe) exist as glass components within the electrode layers 10 and 20.

[0084] The glass may be contained in an amount of 1 to 40 parts by weight, for example, 5 to 35 parts by weight, based on 100 parts by weight of the conductive metal. When the components of the glass are contained within the above content range, a Cu-Ni alloy is formed after sintering, and the connectivity between the external electrode and the internal electrode layer can be improved.

[0085] The glass may be in powder form. The size of the glass, specifically the average particle size (D50), may be 0.1 μm to 5 μm, for example, 0.5 μm to 3 μm. When the size of the glass is within the above range, a Cu-Ni alloy is formed after sintering, and the connectivity between the external electrode and the internal electrode layer can be improved. The average particle size (D50) of the glass can be calculated by measuring the maximum major axis of at least 100 glass particles in the scanning electron microscope (SEM) image of the cross-sectional sample and creating a size distribution cumulative curve. D50 means the size at the point where it becomes 50% in the size distribution cumulative curve.

[0086] The aforementioned electrode layers 10 and 20 may be sintered metal layers of the external electrode.

[0087] The external electrodes 131 and 132 can further include a conductive resin layer (not shown) disposed on the aforementioned electrode layers 10 and 20, and plating layers 30 and 40 disposed so as to cover the conductive resin layer.

[0088] The conductive resin layer extends to the first and second sides or the fifth and sixth sides of the capacitor body 110, and the length of the region (i.e., the band portion) where the conductive resin layer extends and is disposed on the first and second sides or the fifth and sixth sides of the capacitor body 110 may be longer than the length of the region (i.e., the band portion) where the electrode layers 10 and 20 extend and are disposed on the first and second sides or the fifth and sixth sides of the capacitor body 110. That is, the conductive resin layer can be formed on the electrode layers 10 and 20 so as to completely cover the electrode layers 10 and 20.

[0089] The conductive resin layer contains a resin and a conductive metal.

[0090] 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, and can include, for example, a phenolic resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

[0091] The conductive metal contained in the conductive resin layer serves to be electrically connected to the internal electrode layers 121 and 122 or the electrode layers 10 and 20.

[0092] The conductive metal contained in the conductive resin layer can have a spherical shape, a flake shape, or a combination of these shapes. 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 a flake shape and a spherical shape are mixed.

[0093] Here, the spherical shape can also include a shape that is not a perfect sphere, and can include, for example, 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, but for example, the length ratio of the major axis to the minor axis (major axis / minor axis) may be 1.95 or more.

[0094] The external electrodes 131 and 132 can further include a conductive resin layer (not shown) disposed on the aforementioned electrode layers 10 and 20, and plating layers 30 and 40 disposed so as to cover the conductive resin layer.

[0095] Specifically, the plating layers 30 and 40 can include a first plating layer 30 disposed on the first electrode layer 10 and a second plating layer 40 disposed on the second electrode layer 20.

[0096] The plating layers 30 and 40 can include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb) alone, or alloys thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be in a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially laminated, or may be in a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer are sequentially laminated. Also, the plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0097] The plating layer can improve the mountability with the substrate of the multilayer ceramic capacitor 100, the structural reliability, the durability against the outside, the heat resistance, and the equivalent series resistance (ESR).

[0098] Hereinafter, a method for manufacturing the multilayer ceramic capacitor 100 according to an embodiment will be described.

[0099] The multilayer ceramic capacitor 100 according to an embodiment can be manufactured through a step of applying a paste for forming an electrode layer including a conductive metal and a glass composition on one surface of a capacitor body 110 including a dielectric layer 111 and internal electrode layers 121 and 122; and a step of sintering the paste for forming the electrode layer to form the electrode layers 10 and 20 of the external electrodes 131 and 132.

[0100] First, a method for manufacturing the capacitor body 110 will be described.

[0101] The capacitor body 110 can be manufactured through steps of manufacturing a dielectric green sheet using a dielectric slurry and forming a conductive paste layer on the surface of the dielectric green sheet; laminating the dielectric green sheets with the formed conductive paste layer to manufacture a dielectric green sheet laminate; and firing the dielectric green sheet laminate.

[0102] The dielectric slurry can be manufactured by mixing a barium titanate-based compound as a main component powder and optionally a sub-component powder.

[0103] The barium titanate-based compound is the same as described above.

[0104] The sub-component powder can include, for example, manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), vanadium (V), or combinations thereof, but is not limited thereto. Each of the sub-component powders may be included in an amount of 0.01 to 5 mole parts based on 100 mole parts of the main component powder of the barium titanate-based compound.

[0105] The sub-component powder can be used in the form of an oxide or salt compound containing each metal, or in the form of a sol dispersed in an organic solvent.

[0106] In addition, the dielectric slurry can be produced by additionally mixing additives such as a dispersant, a binder, a plasticizer, a lubricant, an antistatic agent, and a solvent.

[0107] For the selective mixing of the main component powder of the barium titanate-based compound and the sub-component powder, a wet ball mill or a stirring mill can be used. When using zirconia balls in a wet ball mill, a large number of zirconia balls with a diameter of 0.1 mm to 10 mm can be used for wet mixing for 8 hours to 48 hours, or 10 hours or 24 hours.

[0108] The produced dielectric slurry is formed as a dielectric layer after firing.

[0109] As a method for forming the produced dielectric slurry into a sheet shape, a tape forming method such as a doctor blade method or a calendar roll method can be used. For example, an on-roll coater using a head discharge method can be used, and then a dielectric green sheet can be obtained by drying the formed body.

[0110] In order to form a conductive paste layer that becomes an internal electrode layer after firing, a conductive paste can be produced by mixing a conductive powder made of a conductive metal or its alloy, a binder, and a solvent. Further, barium titanate powder may be mixed together as a co-material if necessary. The co-material can play a role in suppressing the sintering of the conductive powder during the firing process. The conductive paste 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 to form a conductive paste layer.

[0111] The conductive powder can contain nickel (Ni) or a nickel (Ni) alloy.

[0112] Next, after laminating a plurality of dielectric green sheets each having an internal electrode pattern formed thereon, a dielectric green sheet laminate is manufactured 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 sheet is positioned on the upper and lower surfaces of the dielectric green sheet laminate in the lamination direction.

[0113] The step of selectively cutting the manufactured dielectric green sheet laminate into a predetermined size by dicing or the like can be performed.

[0114] Further, the dielectric green sheet laminate can be solidified and dried to remove a plasticizer or the like if necessary, and can be barrel-polished using a horizontal centrifugal barrel polishing machine or the like after solidification and drying. In barrel polishing, the dielectric green sheet laminate is put into a barrel container together with media and a polishing liquid, and by applying rotational motion, vibration, or the like to the barrel container, unnecessary portions such as burrs generated during cutting can be polished. Further, after barrel polishing, the dielectric green sheet laminate can be washed with a cleaning liquid such as water and dried.

[0115] Next, the dielectric green sheet laminate is subjected to a debinding process and firing to manufacture a capacitor body.

[0116] The debinding process conditions can be appropriately adjusted according to the components of the dielectric layer and the internal electrode layer. 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 atmosphere during the debinding process may be air or a reducing atmosphere.

[0117] 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 electrodes. For example, the firing can be carried out at a temperature of 1100°C to 1400°C, and for example, at a temperature of 1200°C to 1350°C. Also, the firing can be carried out for 0.5 hours to 8 hours, for example, 1 hour to 3 hours. Further, the firing can be carried out in a reducing atmosphere, for example, an atmosphere in which a mixed gas of nitrogen and hydrogen is humidified. When the internal electrode contains nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere may be 1.0×10 -14 MPa to 1.0×10 -10 MPa.

[0118] After the firing process, annealing can be carried out if necessary. Annealing is a process for re-oxidizing the dielectric layer, and can be carried out when the firing process is carried out in a reducing atmosphere. The conditions of the annealing process can also be appropriately adjusted according to the components of the dielectric layer. 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.

[0119] In the debinding process, the firing process, or the annealing process, in order to humidify nitrogen gas, a 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, the firing process, and the annealing process can be carried out continuously or independently.

[0120] Optionally, surface treatments such as sandblasting, laser irradiation, and barrel polishing can be performed on the third and fourth surfaces of the manufactured capacitor body 110. By performing such surface treatments, the ends of the first internal electrode and the second internal electrode are exposed on the outermost surfaces of the third and fourth surfaces, thereby improving the electrical connection between the first external electrode and the second external electrode and the first internal electrode and the second internal electrode, and making it easier to form an alloy portion.

[0121] Hereinafter, a method for manufacturing the external electrodes 131 and 132 will be described.

[0122] The external electrodes 131 and 132 can be manufactured by applying an electrode layer forming paste to one surface of the manufactured capacitor body 110 and sintering it to form the electrode layers 10 and 20.

[0123] The electrode layer forming paste can contain a conductive metal and a glass composition.

[0124] The conductive metal 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. Among these, the conductive metal can include, for example, copper (Cu) or a copper (Cu) alloy.

[0125] The glass composition can contain cobalt oxide (CoO).

[0126] Cobalt oxide (CoO) may be contained in an amount of 0.13 parts by weight to 0.64 parts by weight, for example, 0.133 parts by weight to 0.636 parts by weight, based on 100 parts by weight of the conductive metal.

[0127] The glass composition can further contain iron oxide. The iron oxide can include FeO, Fe2O3, Fe3O4, or combinations thereof.

[0128] Iron oxide may be contained in an amount of 0.18 to 0.91 parts by weight, for example, 0.189 to 0.905 parts by weight, based on 100 parts by weight of the conductive metal.

[0129] In addition to cobalt oxide (CoO) and iron oxide, the glass composition may further contain lithium oxide (Li2O); potassium oxide (K2O); silicon dioxide (SiO2); aluminum oxide (Al2O3); nickel oxide (NiO); silver oxide (Ag2O); sodium oxide (NaO); barium oxide (BaO); calcium oxide (CaO); strontium oxide (SrO); boron oxide (B2O3); zinc oxide (ZnO); tin oxide containing SnO, SnO2, or a combination thereof; copper oxide containing Cu2O, CuO, or a combination thereof; indium oxide (In2O3); titanium dioxide (TiO2); phosphorus pentoxide (P2O5); manganese oxide containing MnO, Mn2O, Mn2O3, Mn3O4, or a combination thereof; germanium oxide (GeO2) or a combination thereof.

[0130] Lithium oxide (Li2O) may be contained in an amount of 5 wt% to 20 wt%, for example 7 wt% to 17 wt%, based on the total amount of the glass composition. Potassium oxide (K2O) may be contained in an amount of 5 wt% to 20 wt%, for example 7 wt% to 17 wt%, based on the total amount of the glass composition. Silicon dioxide (SiO2) may be contained in an amount of 5 wt% to 20 wt%, for example 7 wt% to 17 wt%, based on the total amount of the glass composition. Aluminum oxide (Al2O3) may be contained in an amount of 5 wt% to 15 wt%, for example 7 wt% to 13 wt%, based on the total amount of the glass composition. Nickel oxide (NiO) may be contained in an amount of 0.01 wt% to 20 wt%, for example 0.1 wt% to 15 wt%, based on the total amount of the glass composition. Silver oxide (Ag2O) may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass composition. Sodium oxide (NaO) may be contained in an amount of 0.01 wt% to 25 wt%, for example 0.1 wt% to 20 wt%, based on the total amount of the glass composition. Barium oxide (BaO) may be contained in an amount of 15 wt% to 45 wt%, for example 20 wt% to 40 wt%, based on the total amount of the glass composition. Calcium oxide (CaO) may be contained in an amount of 15 wt% to 45 wt%, for example 20 wt% to 40 wt%, based on the total amount of the glass composition. Strontium oxide (SrO) may be contained in an amount of 15 wt% to 45 wt%, for example 20 wt% to 40 wt%, based on the total amount of the glass composition. Boron oxide (B2O3) may be contained in an amount of 15 wt% to 25 wt%, for example 17 wt% to 23 wt%, based on the total amount of the glass composition. Zinc oxide (ZnO) may be contained in an amount of 1 wt% to 15 wt%, for example 3 wt% to 13 wt%, based on the total amount of the glass composition. Tin oxide may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass composition. Copper oxide may be contained in an amount of 0.01 wt% to 15 wt%, for example 0.1 wt% to 10 wt%, based on the total amount of the glass composition.Indium oxide (In2O3) may be contained in an amount of 0.01% by weight to 15% by weight, for example, 0.1% by weight to 10% by weight, based on the total amount of the glass composition. Titanium dioxide (TiO2) may be contained in an amount of 0.01% by weight to 15% by weight, for example, 0.1% by weight to 10% by weight, based on the total amount of the glass composition. Phosphorus pentoxide (P2O5) may be contained in an amount of 0.01% by weight to 15% by weight, for example, 0.1% by weight to 10% by weight, based on the total amount of the glass composition. Manganese oxide may be contained in an amount of 0.01% by weight to 15% by weight, for example, 0.1% by weight to 10% by weight, based on the total amount of the glass composition. Germanium oxide (GeO2) may be contained in an amount of 0.01% by weight to 15% by weight, for example, 0.1% by weight to 10% by weight, based on the total amount of the glass composition.

[0131] The components of the glass composition can be mixed, heat-treated at a certain temperature or higher, quenched, and then granulated, or the glass can be produced using methods such as vapor phase, liquid phase, and spray pyrolysis.

[0132] The glass composition may be contained in an amount of 1 part by weight to 40 parts by weight, for example, 5 parts by weight to 35 parts by weight, per 100 parts by weight of the conductive metal.

[0133] The paste for forming the electrode layer can further contain a binder, a solvent, a dispersant, a plasticizer, an oxide powder, and the like.

[0134] As the binder, for example, ethyl cellulose, acrylic, butyral, etc. can be used, and as the solvent, organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, toluene, or aqueous solvents can be used.

[0135] As methods for applying the paste for forming the electrode layer onto the outer surface of the capacitor body 110, a dipping method, various printing methods such as screen printing, an application method using a dispenser, a spraying method using a spray, etc. can be used. The paste for forming the electrode layer is applied at least to the third and fourth surfaces of the capacitor body 110, and may also be 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 selectively formed.

[0136] Sintering can be performed at a temperature of 400°C to 850°C. When sintering is performed within the above temperature range, nickel oxide (NiO) can be easily reduced while forming a Cu-Ni alloy. From the formation of the Cu-Ni alloy, not only the connectivity between the external electrode and the internal electrode layer is improved, but also the capacitance variation can be improved and the equivalent series resistance (ESR) can be lowered.

[0137] Next, selectively, after applying the paste for forming the conductive resin layer onto the outer surface of the capacitor body 110 on which the electrode layers 10 and 20 are formed, it can be cured to form a conductive resin layer.

[0138] The paste for forming the conductive resin layer can contain a resin and, optionally, a conductive metal or a non-conductive filler. Since the description regarding the conductive metal and the resin is the same as that described above, repetitive description is omitted. Also, the paste for forming the conductive resin layer can optionally contain a binder, a solvent, a dispersant, a plasticizer, an oxide powder, etc. As the binder, for example, ethyl cellulose, acrylic, butyral, etc. can be used, and as the solvent, an organic solvent such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, toluene, or an aqueous solvent can be used.

[0139] As an example, the method for forming the conductive resin layer can be to dip the capacitor body 110 into the paste for forming the conductive resin layer and then cure it, or to print the paste for forming the conductive resin layer on the surface of the capacitor body 110 by a screen printing method, a gravure printing method, etc., or to apply the paste for forming the conductive resin layer on the surface of the capacitor body 110 and then cure it to form the layer.

[0140] Next, plating layers 30 and 40 can be formed outside the conductive resin layer.

[0141] As an example, the plating layer can be formed by a plating method, and can also be formed by sputtering or electroplating.

[0142] Hereinafter, the above-described embodiments will be described in more detail through examples. However, the following examples are for illustrative purposes only and do not limit the scope of the rights.

Example

[0143] (Manufacture of multilayer ceramic capacitor) Examples 1 to 13 and Comparative Examples 1 to 13 After manufacturing a dielectric green sheet using barium titanate (BaTiO3) as the main component powder, a conductive paste layer containing nickel (Ni) was printed on the surface of the dielectric green sheet, and the dielectric green sheet (width × length × height = 3.2 mm × 2.5 mm × 2.5 mm) with the conductive paste layer formed was laminated and pressed to manufacture a dielectric green sheet laminate. The dielectric green sheet laminate was subjected to a plasticizing process in a nitrogen atmosphere at 400°C or lower and then fired at a firing temperature of 1300°C or lower and a hydrogen concentration of 1.0% H2 or lower to manufacture a capacitor body.

[0144] An electrode layer forming paste containing copper (Cu), 10 parts by weight of a glass composition with respect to 100 parts by weight of copper (Cu), and 8 parts by weight of an acrylic binder was applied to one side of a capacitor body. Here, in the case of Examples 1 to 13 and Comparative Examples 11 to 13, the glass composition was composed of cobalt oxide (CoO) and iron oxide (FeO x ), and additional components having the composition shown in Table 1 below. In the case of Comparative Examples 1 to 10, it was composed only of the additional components having the composition shown in Table 1 below.

[0145] Next, it was sintered at a temperature of 400°C to 850°C as shown in Table 2 below to form an electrode layer of an external electrode. Subsequently, a multilayer ceramic capacitor was manufactured through processes such as plating.

[0146]

Table 1

[0147]

Table 2

[0148] Evaluation 1: EPMA analysis EPMA (Electron Probe Microanalyzer) analysis was performed on the multilayer ceramic capacitors manufactured in Examples 1 to 13 and Comparative Examples 1 to 13, and the results are shown in Tables 3 and 4 below.

[0149] The EPMA analysis was carried out as follows. After laying each of the multilayer ceramic capacitors manufactured in Examples 1 to 13 and Comparative Examples 1 to 13 horizontally, the periphery of the multilayer ceramic capacitor was fixed with an epoxy resin and polished with a polishing machine to obtain a cross-sectional sample having an LT surface so that the capacitor body and the external electrode could be observed. EPMA (Electron Probe Microanalyzer) analysis was measured on the obtained cross-sectional sample. As a measurement result, mapping of each element present in the electrode layer of the external electrode and the content by element were confirmed.

[0150]

Table 3

[0151]

Table 4

[0152] Referring to Table 3 and Table 4 above, in the case of Examples 1 to 13, it can be confirmed that cobalt (Co) exists within an appropriate content range as a glass component contained in the electrode layer of the external electrode.

[0153] Evaluation 2: SEM Analysis SEM (scanning electron microscope) analysis was performed on the multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1, and the results are shown in FIGS. 4 and 5.

[0154] The SEM analysis was performed as follows. After laying each of the multilayer ceramic capacitors manufactured in Example 1 and Comparative Example 1 horizontally, the periphery of the multilayer ceramic capacitor was fixed with an epoxy resin and polished with a polishing machine to obtain a cross-sectional sample having an LT plane so that the capacitor body and the external electrode could be observed. The obtained cross-sectional sample was measured with a scanning electron microscope (SEM). The SEM was measured, for example, using TESCAN SOLARIS X under the conditions of 5 keV and 300 pA in a region of approximately 55 μm × 50 μm in horizontal × vertical so that the surface where the internal electrode layer of the capacitor body and the external electrode are in contact can be seen.

[0155] FIG. 4 is an SEM analysis image showing the internal electrode layer and the external electrode of the multilayer ceramic capacitor according to Example 1, and FIG. 5 is an SEM analysis image showing the internal electrode layer and the external electrode of the multilayer ceramic capacitor according to Comparative Example 1.

[0156] Referring to FIGS. 4 and 5, in the case of Example 1 where the electrode layer of the external electrode contains cobalt (Co) as a glass component, it has a structure with excellent connectivity between the internal electrode layer and the external electrode. On the contrary, in the case of Comparative Example 1 where cobalt (Co) is not contained, it can be confirmed that it has a structure with reduced connectivity between the internal electrode layer and the external electrode.

[0157] Evaluation 3: Capacitance, ESR, and Moisture Resistance Reliability For the multilayer ceramic capacitors manufactured in Examples 1 to 13 and Comparative Examples 1 to 13, capacitance, equivalent series resistance (ESR), and moisture resistance severe evaluation were measured, and the results are shown in Table 5 and FIG. 6 below.

[0158] - The capacitance was measured under the conditions of 1 kHz and 0.5 V. Regarding the measurement results, for 1000 products, less than 70% of the non-defective products were determined as X, 70% or more to less than 80% of the non-defective products were determined as △, 80% or more to less than 90% of the non-defective products were determined as ○, and 90% or more of the non-defective products were determined as ◎. - The equivalent series resistance (ESR) was measured under the condition of 1 MHz. Regarding the measurement results, for 1000 products, products with 100 mΩ or less were determined as non-defective products. Less than 97% of the non-defective products were determined as X, 97% or more to less than 98% of the non-defective products were determined as △, 98% or more to less than 99% of the non-defective products were determined as ○, and 99% or more of the non-defective products were determined as ◎.

[0159] - The moisture resistance severe evaluation was measured under the conditions of 95 °C, relative humidity (R.H.) 95%, and 20 hours using an ESPEC (PR-3J, 8585) device. During the analysis process, when the IR (insulation resistance) is 5th power or less, it is defined as a failure (fail), and the determination was made based on the failure occurrence time for 20k quantities. When the failure time is 48 hours or less, it is determined as X, when the failure time exceeds 48 hours to 216 hours or less, it is determined as △, when the failure time exceeds 216 hours to 1024 hours or less, it is determined as ○, and when the failure time exceeds 1024 hours, it is determined as ◎.

[0160] [Table 5]

[0161] Referring to Table 5, it can be seen that in Examples 1 to 13 where the electrode layer of the external electrode contains cobalt (Co) as a glass component within a predetermined content range, all of the capacitance, ESR, and moisture resistance reliability are excellent. On the contrary, in Comparative Examples 1 to 10 where the electrode layer of the external electrode does not contain cobalt (Co) and Comparative Examples 11 to 13 where cobalt (Co) deviates from the predetermined content range, it can be seen that the capacitance, ESR, and moisture resistance reliability decrease.

[0162] Figure 6 is a graph showing the capacitance of the multilayer ceramic capacitor according to Example 1 and Comparative Example 1.

[0163] Referring to Figure 6, it can be seen that in the case of Example 1 where the electrode layer of the external electrode contains cobalt (Co) as a glass component, the capacitance variation characteristics are improved compared to Comparative Example 1 where cobalt (Co) is not contained.

[0164] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made and implemented within the scope of the claims, the description of the invention, and the appended drawings, and it is natural that these also belong to the scope of the present invention.

Description of Reference Numerals

[0165] 10: First Electrode Layer 20: Second Electrode Layer 30: First Plating Layer 40: Second Plating Layer 100: Multilayer Ceramic Capacitor 110: Capacitor Body 111: Dielectric Layer 121: First Internal Electrode 122: Second Internal Electrode 131: First External Electrode 132: Second External Electrode

Claims

1. A capacitor body including a dielectric layer and an internal electrode layer, and an external electrode disposed outside the capacitor body, wherein the external electrode includes an electrode layer directly located on a cross-section of the capacitor body so as to be electrically connected to at least one of the internal electrode layers, the electrode layer includes a conductive metal; and a glass containing cobalt (Co), the cobalt (Co) is contained in an amount of 0.13 parts by weight to 0.64 parts by weight with respect to 100 parts by weight of the conductive metal, a multilayer ceramic capacitor.

2. The cobalt (Co) is contained in a region near the interface defined as a region from the interface between the electrode layer of the external electrode and the internal electrode layer to a point in the longitudinal direction (L axis) that is 5% to 15% of the total thickness of the external electrode, the multilayer ceramic capacitor according to Claim 1.

3. The glass further includes iron (Fe), the multilayer ceramic capacitor according to Claim 1.

4. The iron (Fe) is contained in an amount of 0.18 parts by weight to 0.91 parts by weight with respect to 100 parts by weight of the conductive metal, the multilayer ceramic capacitor according to Claim 3.

5. The iron (Fe) is contained in a region near the interface defined as a region from the interface between the electrode layer of the external electrode and the internal electrode layer to a point in the longitudinal direction (L axis) that is 5% to 15% of the total thickness of the external electrode, the multilayer ceramic capacitor according to Claim 3.

6. The glass further includes lithium (Li), potassium (K), silicon (Si), aluminum (Al), nickel (Ni), silver (Ag), sodium (Na), barium (Ba), calcium (Ca), strontium (Sr), boron (B), zinc (Zn), tin (Sn), copper (Cu), indium (In), titanium (Ti), phosphorus (P), manganese (Mn), germanium (Ge), or a combination thereof, the multilayer ceramic capacitor according to Claim 1.

7. With respect to the total amount of the glass, the lithium (Li) is contained in an amount of 5% to 20% by weight, the potassium (K) is contained in an amount of 5% to 20% by weight, the silicon (Si) is contained in an amount of 5% to 20% by weight, the aluminum (Al) is contained in an amount of 5% to 15% by weight, the nickel (Ni) is contained in an amount of 0.01% to 20% by weight, the silver (Ag) is contained in an amount of 0.01% to 15% by weight, the sodium (Na) is contained in an amount of 0.01% to 25% by weight, The barium (Ba) is contained in an amount of 15% by weight to 45% by weight, the calcium (Ca) is contained in an amount of 15% by weight to 45% by weight, the strontium (Sr) is contained in an amount of 15% by weight to 45% by weight, the boron (B) is contained in an amount of 15% by weight to 25% by weight, the zinc (Zn) is contained in an amount of 1% by weight to 15% by weight, the tin (Sn) is contained in an amount of 0.01% by weight to 15% by weight, the copper (Cu) is contained in an amount of 0.01% by weight to 15% by weight, the indium (In) is contained in an amount of 0.01% by weight to 15% by weight, the titanium (Ti) is contained in an amount of 0.01% by weight to 15% by weight, the phosphorus (P) is contained in an amount of 0.01% by weight to 15% by weight, the manganese (Mn) is contained in an amount of 0.01% by weight to 15% by weight, the germanium (Ge) is contained in an amount of 0.01% by weight to 15% by weight, the multilayer ceramic capacitor according to claim 6.

8. The glass is contained in an amount of 1 part by weight to 40 parts by weight with respect to 100 parts by weight of the conductive metal, the multilayer ceramic capacitor according to claim 1.

9. The average particle diameter (D50) of the glass is 0.1 μm to 5 μm, the multilayer ceramic capacitor according to claim 1.

10. The conductive metal includes 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, the multilayer ceramic capacitor according to claim 1.

11. Applying a paste for forming an electrode layer containing a conductive metal and a glass composition on one surface of a capacitor body including a dielectric layer and an internal electrode layer; and sintering the paste for forming the electrode layer to form an electrode layer of an external electrode, wherein the glass composition contains cobalt oxide (CoO) in an amount of 0.13 parts by weight to 0.64 parts by weight with respect to 100 parts by weight of the conductive metal, a method for manufacturing a multilayer ceramic capacitor.

12. The sintering is performed at a temperature of 400°C to 850°C, the method for manufacturing a multilayer ceramic capacitor according to claim 11.

13. The glass composition further contains iron oxide, The iron oxide is FeO, Fe ２ O ３ , Fe ３ O ４ or a combination thereof, and a method for manufacturing the multilayer ceramic capacitor according to claim 11.

14. The iron oxide is contained in an amount of 0.18 parts by weight to 0.91 parts by weight with respect to 100 parts by weight of the conductive metal, the method for manufacturing a multilayer ceramic capacitor according to claim 13.

15. The glass composition contains lithium oxide (Li ２ O); potassium oxide (K ２ O); silicon dioxide (SiO ２ ); aluminum oxide (Al ２ O ３ ); nickel oxide (NiO); silver oxide (Ag ２ O); sodium oxide (NaO); barium oxide (BaO); calcium oxide (CaO); strontium oxide (SrO); boron oxide (B ２ O ３ ); zinc oxide (ZnO); tin oxide containing SnO, SnO ２ , or a combination thereof; copper oxide containing Cu ２ O, CuO, or a combination thereof; indium oxide (In ２ O ３ ); titanium dioxide (TiO ２ ); phosphorus pentoxide (P ２ O ５ ); manganese oxide containing MnO, Mn ２ O, Mn ２ O ３ , Mn ３ O ４ , or a combination thereof; germanium oxide (GeO ２ ), or a method for manufacturing a multilayer ceramic capacitor according to claim 11, further comprising a combination thereof.

16. With respect to the total amount of the glass composition, The lithium oxide (Li ２ O) is contained in an amount of 5% by weight to 20% by weight, The potassium oxide (K ２ O) is contained in an amount of 5% by weight to 20% by weight, The silicon dioxide (SiO ２ ) is contained in an amount of 5% by weight to 20% by weight, The aluminum oxide (Al ２ O ３ ) is contained in an amount of 5% by weight to 15% by weight, The nickel oxide (NiO) is contained in an amount of 0.01% by weight to 20% by weight, The silver oxide (Ag ２ O) is contained in an amount of 0.01% by weight to 15% by weight, the sodium oxide (NaO) is contained in an amount of 0.01% by weight to 25% by weight, the barium oxide (BaO) is contained in an amount of 15% by weight to 45% by weight, the calcium oxide (CaO) is contained in an amount of 15% by weight to 45% by weight, the strontium oxide (SrO) is contained in an amount of 15% by weight to 45% by weight, The boron oxide (B ２ O ３ ) is contained in an amount of 15% by weight to 25% by weight, the zinc oxide (ZnO) is contained in an amount of 1% by weight to 15% by weight, the tin oxide is contained in an amount of 0.01% by weight to 15% by weight, the copper oxide is contained in an amount of 0.01% by weight to 15% by weight, The indium oxide (In ２ O ３ ) is contained in an amount of 0.01% by weight to 15% by weight, The titanium dioxide (TiO ２ ) is contained in an amount of 0.01% to 15% by weight, The phosphorus pentoxide (P ２ O ５ ) is contained in an amount of 0.01% by weight to 15% by weight, the manganese oxide is contained in an amount of 0.01% by weight to 15% by weight, The germanium oxide (GeO ２ ) is contained in an amount of 0.01% by weight to 15% by weight. A method for manufacturing a multilayer ceramic capacitor according to claim 15.

17. The method for manufacturing a multilayer ceramic capacitor according to claim 11, wherein the glass composition is contained in an amount of 1 part by weight to 40 parts by weight with respect to 100 parts by weight of the conductive metal.

18. The method for manufacturing a multilayer ceramic capacitor according to claim 11, wherein the conductive metal includes 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.

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