Multilayer ceramic capacitor
The multilayer ceramic capacitor addresses connectivity and capacitance issues by using conductive carbon and metal layers to improve electrode connections, resulting in enhanced capacitance without electrical loss.
Patent Information
- Application Number
- JP2024075279
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-12-13
- Filing Date
- 2024-05-07
- Publication Date
- 2025-06-25
AI Technical Summary
Multilayer ceramic capacitors face issues with insufficient connectivity between internal and external electrodes, and excessive thickness of external electrodes can reduce the portion contributing to capacitance.
The multilayer ceramic capacitor design includes a ceramic body with internal electrodes connected to external electrodes through a layered structure comprising conductive carbon layers and metal layers, with specific materials like graphite, graphene, and nickel, ensuring improved connectivity and reduced external electrode volume.
This design enhances connectivity between internal and external electrodes, allowing for a larger capacitance contribution without electrical loss, thereby increasing the overall capacitance of the capacitor.
Smart Images
Figure 2025094878000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a multilayer ceramic capacitor.
Background Art
[0002] As electronic components using ceramic materials, there are 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, having a high capacitance guaranteed, 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 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] A multilayer ceramic capacitor can include internal electrodes disposed inside the ceramic body and external electrodes disposed outside the ceramic body and connected to the internal electrodes. However, if the external electrodes are excessively thick, there may be a problem that the portion contributing to the capacitance relatively decreases.
[0005] On the other hand, external electrodes can also be formed from a conductive carbon layer, and in this case, the connectivity between the internal electrodes and the external electrodes may be insufficient.
Summary of the Invention
Problems to be Solved by the Invention
[0006] One aspect of the embodiment aims to provide a multilayer ceramic capacitor with improved connectivity between internal electrodes and external electrodes.
[0007] Also, one aspect of the embodiment aims to provide a multilayer ceramic capacitor that can design a larger portion contributing to capacitance by relatively reducing the volume of the external electrode without electrical loss.
[0008] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems and can be variously extended within the scope of the technical idea included in the present invention.
Means for Solving the Problems
[0009] A multilayer ceramic capacitor according to an embodiment includes a ceramic body including a first surface and a second surface facing each other in a first direction, a third surface and a fourth surface facing each other in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface facing each other in a third direction and connecting the first surface and the second surface, a plurality of first internal electrodes and a plurality of second internal electrodes disposed inside the ceramic body, a first external electrode disposed outside the ceramic body and connected to the plurality of first internal electrodes, and a second external electrode disposed outside the ceramic body and connected to the plurality of second internal electrodes. The first external electrode includes a first electrode layer disposed on the first surface and electrically connected to the plurality of first internal electrodes, a first conductive carbon layer disposed on the first electrode layer, and a first metal layer disposed on the fifth surface and in contact with the first conductive carbon layer between the first surface and the fifth surface. The second external electrode can include a second electrode layer disposed on the second surface and electrically connected to the plurality of second internal electrodes, a second conductive carbon layer disposed on the second electrode layer, and a second metal layer disposed on the fifth surface and in contact with the second conductive carbon layer between the second surface and the fifth surface.
[0010] In addition, the first conductive carbon layer and the second conductive carbon layer can include one or more of graphite, graphene, carbon nanotube, fullerene, and carbon black.
[0011] In addition, the first electrode layer can include a conductive metal and glass, and the second electrode layer can include a conductive metal and glass.
[0012] In addition, the conductive metal of the first electrode layer and the conductive metal of the second electrode layer can include nickel (Ni).
[0013] In addition, the first electrode layer includes a first base layer connected to the plurality of first internal electrodes and a second base layer disposed on the first base layer, and the second electrode layer can include a third base layer connected to the plurality of second internal electrodes and a fourth base layer disposed on the third base layer.
[0014] In addition, the first base layer and the second base layer can include a conductive metal and glass, and the third base layer and the fourth base layer can include a conductive metal and glass.
[0015] In addition, the conductive metal of the first base layer and the conductive metal of the third base layer can include nickel (Ni).
[0016] In addition, the conductive metal of the second base layer and the conductive metal of the fourth base layer can include copper (Cu).
[0017] In addition, the first external electrode can further include a first plating layer covering the first metal layer and the first conductive carbon layer, and the second external electrode can further include a second plating layer covering the second metal layer and the second conductive carbon layer.
[0018] Further, the first plating layer may include a first layer covering the first metal layer and the first conductive carbon layer, a second layer covering the first layer, and a third layer covering the second layer.
[0019] Further, the first layer may contain copper (Cu), the second layer may contain nickel (Ni), and the third layer may contain tin (Sn).
[0020] Further, the second plating layer may include a first layer covering the second metal layer and the second conductive carbon layer, a second layer covering the first layer, and a third layer covering the second layer.
[0021] Further, the first layer may contain copper (Cu), the second layer may contain nickel (Ni), and the third layer may contain tin (Sn).
Advantages of the Invention
[0022] According to the multilayer ceramic capacitor according to the embodiment, the connectivity between the internal electrode and the external electrode can be improved.
[0023] Further, according to the multilayer ceramic capacitor according to the embodiment, by relatively reducing the volume of the external electrode without electrical loss, the portion contributing to the capacitance can be further increased.
Brief Description of the Drawings
[0024]
Figure 1
Figure 2
Figure 3
Figure 4
Modes for Carrying Out the Invention
[0025] 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 the drawings, parts that are unnecessary for explanation for clearly explaining the present invention are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. Also, in the attached drawings, some components are exaggerated, omitted, or illustrated schematically, and the sizes of the components do not fully reflect the actual sizes.
[0026] The attached drawings are merely for facilitating 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 to include all modifications, equivalents, or alternatives included in the idea and technical scope of the present invention.
[0027] 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.
[0028] 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 the gravitational force.
[0029] 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 it 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.
[0030] Also, throughout the specification, when referring to "on a plane", this means when looking at the target part from above, and when referring to "in a cross-section", this means when looking at the cross-section obtained by vertically cutting the target part from the side.
[0031] Also, throughout the specification, when referring to "being connected", this does not only mean that two or more components are directly connected, but also means that two or more components are indirectly connected through other components, not only physically connected but also electrically connected, or can be meant to be integrated although named differently depending on their positions or functions.
[0032] FIG. 1 is a perspective view schematically showing a multilayer ceramic capacitor according to an embodiment, FIG. 2 is a cross-sectional view taken along line II-II' of FIG. 1, FIG. 3 is an exploded perspective view showing the stacked structure of internal electrodes in the multilayer ceramic capacitor of FIG. 1, and FIG. 4 is a diagram schematically showing the process of forming the external electrodes of the multilayer ceramic capacitor of FIG. 1. For convenience of explanation, only the process of forming the external electrodes on one side of the multilayer ceramic capacitor is shown in FIG. 4, but the external electrodes on the other side can also be formed in the same process.
[0033] Referring to FIGS. 1, 2, 3, and 4, the multilayer ceramic capacitor 1000 according to this embodiment includes a ceramic body 110, a first external electrode 120, a second external electrode 130, a plurality of first internal electrodes 150, and a plurality of second internal electrodes 160.
[0034] First, to clearly explain this embodiment, if directions are defined, the L-axis, W-axis, and T-axis shown in the drawings respectively indicate the axes in the length direction, width direction, and thickness direction of the multilayer ceramic capacitor 1000.
[0035] The thickness direction (T-axis direction) may be a direction perpendicular to the wide surface (main surface) of a component having a sheet shape. For example, the thickness direction (T-axis direction) can be used as the same concept as the direction in which the dielectric layer 140 is laminated.
[0036] The length direction (L-axis direction) may be a direction parallel to the wide surface (main surface) of a component having a sheet shape and intersecting (or orthogonal) to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be the direction in which the first external electrode 120 and the second external electrode 130 face each other.
[0037] The width direction (W-axis direction) may be a direction parallel to the wide surface (main surface) of a component having a sheet shape and intersecting (or orthogonal) to both the thickness direction (T-axis direction) and the length direction (L-axis direction) simultaneously.
[0038] The ceramic body 110 may be generally hexahedral in shape, but this embodiment is not limited thereto. Due to shrinkage during sintering, the ceramic body 110 may not be a perfect hexahedral shape but can have a substantially hexahedral shape. For example, the ceramic body 110 is generally a straight hexahedron, but the portions corresponding to corners and vertices can have a rounded shape.
[0039] In this embodiment, for convenience of explanation, the surfaces facing each other in the length direction (L-axis direction) are defined as the first surface S1 and the second surface S2, the surfaces facing each other in the width direction (W-axis direction) and connecting the first surface S1 and the second surface S2 are defined as the third surface S3 and the fourth surface S4, and the surfaces facing each other in the thickness direction (T-axis direction) and connecting the first surface S1 and the second surface S2 are defined as the fifth surface S5 and the sixth surface S6.
[0040] Therefore, the first direction, in which the first surface S1 and the second surface S2 face each other, may be the length direction (L-axis direction), and the second direction and the third direction, which are perpendicular to the first direction and perpendicular to each other, may be the thickness direction (T-axis direction) and the width direction (W-axis direction) or the width direction (W-axis direction) and the thickness direction (T-axis direction), respectively.
[0041] The length of the ceramic body 110 can be based on an optical microscope or a scanning electron microscope (SEM) photograph of the length direction (L-axis direction)-thickness direction (T-axis direction) cross section at the center in the width direction (W-axis direction) of the ceramic body 110, and means the maximum value among the lengths of a plurality of line segments parallel to the length direction (L-axis direction) by connecting two outermost boundary lines facing the length direction (L-axis direction) of the ceramic body 110 shown in the above cross-sectional photograph, respectively. On the other hand, the length of the ceramic body 110 can mean the minimum value among the lengths of a plurality of line segments parallel to the length direction (L-axis direction) by connecting two outermost boundary lines facing the length direction (L-axis direction) of the ceramic body 110 shown in the above cross-sectional photograph, respectively. On the other hand, the length of the ceramic body 110 can mean the arithmetic average value of the lengths of at least two line segments among a plurality of line segments parallel to the length direction (L-axis direction) by connecting two outermost boundary lines facing the length direction (L-axis direction) of the ceramic body 110 shown in the above cross-sectional photograph, respectively.
[0042] The thickness of the ceramic body 110 can be defined as the maximum value among the lengths of a plurality of line segments parallel to the thickness direction (T-axis direction) by connecting two outermost boundary lines facing each other in the thickness direction (T-axis direction) of the ceramic body 110 shown in the aforementioned cross-sectional photograph, based on an optical microscope or a scanning electron microscope (SEM) photograph of the length direction (L-axis direction)-thickness direction (T-axis direction) cross section at the central portion in the width direction (W-axis direction) of the ceramic body 110. On the other hand, the thickness of the ceramic body 110 can be defined as the minimum value among the lengths of a plurality of line segments parallel to the thickness direction (T-axis direction) by connecting two outermost boundary lines facing each other in the thickness direction (T-axis direction) of the ceramic body 110 shown in the aforementioned cross-sectional photograph. On the other hand, the thickness of the ceramic body 110 can be defined as the arithmetic mean value of the lengths of at least two line segments among a plurality of line segments parallel to the thickness direction (T-axis direction) by connecting two outermost boundary lines facing each other in the thickness direction (T-axis direction) of the ceramic body 110 shown in the aforementioned cross-sectional photograph.
[0043] The width of the ceramic body 110 can be defined as the maximum value among the lengths of a plurality of line segments parallel to the width direction (W-axis direction) by connecting two outermost boundary lines facing each other in the width direction (W-axis direction) of the ceramic body 110 shown in the aforementioned cross-sectional photograph, based on an optical microscope or a scanning electron microscope (SEM) photograph of the length direction (L-axis direction)-width direction (W-axis direction) cross section at the central portion in the thickness direction (T-axis direction) of the ceramic body 110. On the other hand, the width of the ceramic body 110 can be defined as the minimum value among the lengths of a plurality of line segments parallel to the width direction (W-axis direction) by connecting two outermost boundary lines facing each other in the width direction (W-axis direction) of the ceramic body 110 shown in the aforementioned cross-sectional photograph. On the other hand, the width of the ceramic body 110 can be defined as the arithmetic mean value of the lengths of at least two line segments among a plurality of line segments parallel to the width direction (W-axis direction) by connecting two outermost boundary lines facing each other in the width direction (W-axis direction) of the ceramic body 110 shown in the aforementioned cross-sectional photograph.
[0044] The ceramic body 110 can include a plurality of dielectric layers 140 laminated in the thickness direction (T-axis direction). The boundary between the dielectric layers 140 may be unclear. For example, the boundary between the dielectric layers 140 is difficult to confirm without using a scanning electron microscope (SEM), and the plurality of dielectric layers 140 may appear as an integral structure.
[0045] The first internal electrode 150 and the second internal electrode 160 can be alternately laminated with the dielectric layer 140 interposed therebetween. Such a laminated structure may be repeated within the ceramic body 110. The internal electrode closest to the fifth surface S5 of the ceramic body 110 may be the first internal electrode 150 or the second internal electrode 160, and the internal electrode closest to the sixth surface S6 may be the first internal electrode 150 or the second internal electrode 160.
[0046] The first internal electrode 150 and the second internal electrode 160 have different polarities from each other and can be electrically insulated from each other by the dielectric layer 140 disposed therebetween.
[0047] The first internal electrode 150 and the second internal electrode 160 can be arranged so as to be displaced from each other in the length direction (L-axis direction) with the dielectric layer 140 interposed therebetween. One end portion of the first internal electrode 150 is exposed through the first surface S1 of the ceramic body 110, and one end portion of the second internal electrode 160 is exposed through the second surface S2 of the ceramic body 110. The end portion of the first internal electrode 150 exposed from the first surface S1 of the ceramic body 110 can be connected to the first external electrode 120. The end portion of the second internal electrode 160 exposed from the second surface S2 of the ceramic body 110 can be connected to the second external electrode 130.
[0048] The first internal electrode 150 and the second internal electrode 160 can be formed by printing a conductive paste containing a conductive metal on the surface of the dielectric layer 140. For example, a conductive paste containing nickel (Ni) or a nickel (Ni) alloy can be printed on the surface of the dielectric layer by screen printing or gravure printing to form the internal electrodes. However, the present embodiment is not limited thereto.
[0049] As an example, the average thickness of the first internal electrode 150 and the second internal electrode 160 may be approximately 0.1 μm or more and 2 μm or less.
[0050] Here, the thickness of the internal electrode can mean the average thickness of one internal electrode disposed between two dielectric layers. The average thickness of the internal electrode is based on a scanning electron microscope (SEM) photograph at a magnification of 10,000 times with respect to the length-thickness (T-axis direction) cross section at the center in the width direction (W-axis direction) of the ceramic body 110. The thickness of one internal electrode shown in the aforementioned cross-sectional photograph may be the arithmetic mean value of the values measured at 30 points having equal intervals in the length direction (L-axis direction). The aforementioned 30 points can be specified in the active region described later. After measuring the average thickness of each of the 10 internal electrodes in such a manner and then deriving the arithmetic mean value of the measured values, the average thickness of the internal electrode can be further generalized.
[0051] When a voltage is applied to the first external electrode 120 and the second external electrode 130, charges are accumulated between the first internal electrode 150 and the second internal electrode 160 facing each other. That is, a capacitance can be obtained between the first internal electrode 150 electrically connected to the first external electrode 120 and the second internal electrode 160 electrically connected to the second external electrode 130. The capacitance of the multilayer ceramic capacitor 1000 is proportional to the overlapping area of the first internal electrode 150 and the second internal electrode 160 that overlap each other along the thickness direction (T-axis direction).
[0052] In other words, the multilayer ceramic capacitor 1000 can include an active region and a margin region. The active region can be referred to as a region where the first internal electrode 150 and the second internal electrode 160 overlap along the thickness direction (T-axis direction), and the margin region can be referred to as a region between the active region and the first surface S1 of the ceramic body 110 and a region between the active region and the second surface S2 of the ceramic body 110.
[0053] The first cover layer 143 and the second cover layer 145 can be arranged outside the active region in the thickness direction (T-axis direction).
[0054] The first cover layer 143 is arranged between the fifth surface S5 of the ceramic body 110 and the internal electrode closest to it. The second cover layer 145 is arranged between the sixth surface S6 of the ceramic body 110 and the internal electrode closest to it.
[0055] That is, the first cover layer 143 can be arranged above the topmost internal electrode in the ceramic body 110, and the second cover layer 145 can be arranged below the lowermost internal electrode. The first cover layer 143 and the second cover layer 145 can have the same composition as the dielectric layer 140. One or more dielectric layers can be laminated on the outer surfaces of the uppermost internal electrode and the lowermost internal electrode respectively to form the first cover layer 143 and the second cover layer 145.
[0056] The first cover layer 143 and the second cover layer 145 can play a role in preventing damage to the first internal electrode 150 and the second internal electrode 160 due to physical or chemical stress.
[0057] The dielectric layer 140 can include a high-permittivity ceramic material. For example, the ceramic material can include a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. Further, these components can further include auxiliary components such as manganese (Mn) compounds, iron (Fe) compounds, chromium (Cr) compounds, cobalt (Co) compounds, nickel (Ni) compounds, etc. For example, the dielectric layer is (Ba 1-x Ca x )TiO3 with partial solid solution of calcium (Ca), zirconium (Zr), etc. in BaTiO3, Ba(Ti 1-y Ca y )O3, (Ba 1-x Ca x )(Ti 1-y Zr y )O3 or Ba(Ti 1-y Zr y )O3, etc., but the present invention is not limited thereto.
[0058] Also, the dielectric layer 140 may further include one or more of a ceramic additive, an organic solvent, a plasticizer, a binder, and a dispersant. The ceramic additive may be, for example, a transition metal oxide or carbide, a rare earth element, magnesium (Mg), aluminum (Al), etc.
[0059] As an example, the average thickness of the dielectric layer 140 may be 0.1 μm to 10 μm, but the present embodiment is not limited thereto.
[0060] The first external electrode 120 and the second external electrode 130 are disposed outside the ceramic body 110.
[0061] The first external electrode 120 is disposed on the first surface S1 of the ceramic body 110 and can extend to the fifth surface S5. That is, the first external electrode 120 can be disposed on the first surface S1 and the fifth surface S5 of the ceramic body 110. In other embodiments, the first external electrode 120 can also be disposed on the third surface S3 and the fourth surface S4 of the ceramic body 110.
[0062] The second external electrode 130 is disposed on the second surface S2 of the ceramic body 110 and can extend to the fifth surface S5. That is, the second external electrode 130 can be disposed on the second surface S2 and the fifth surface S5 of the ceramic body 110. In other embodiments, the second external electrode 130 can also be disposed on the third surface S3 and the fourth surface S4 of the ceramic body 110.
[0063] The first external electrode 120 includes a first connection portion 121, a first band portion 123, and a first corner portion 125.
[0064] The first connection portion 121 covers the first surface S1 of the ceramic body 110 and is a portion that is connected to and electrically connected to the exposed ends of the plurality of first internal electrodes 150.
[0065] In other embodiments, the first connection portion 121 can cover a part of the first surface S1 of the ceramic body 110.
[0066] The first band portion 123 extends from the first connection portion 121 and covers at least a part of the fifth surface S5 of the ceramic body 110. The first band portion 123 can be configured such that the first external electrode 120 is more firmly fixed to the ceramic body 110.
[0067] The first corner portion 125 may be a portion that connects the first connection portion 121 and the first band portion 123.
[0068] The second external electrode 130 includes a second connection portion 131, a second band portion 133, and a second corner portion 135, respectively.
[0069] The second connection portion 131 covers the second surface S2 of the ceramic body 110 and is a portion that is connected to and electrically connected to the exposed ends of the plurality of second internal electrodes 160.
[0070] In other embodiments, the second connection portion 131 can cover a part of the second surface S2 of the ceramic body 110.
[0071] The second band portion 133 extends from the second connection portion 131 and covers at least a part of the fifth surface S5 of the ceramic body 110. The second band portion 133 can be configured such that the second external electrode 130 is more strongly fixed to the ceramic body 110.
[0072] The second corner portion 135 may be a portion that connects the second connection portion 131 and the second band portion 133.
[0073] Based on an optical microscope or a scanning electron microscope (SEM) photograph of the length direction (L-axis direction)-thickness direction (T-axis direction) cross section at the center in the width direction (W-axis direction) of the multilayer ceramic capacitor 1000, in the multilayer ceramic capacitor 1000 shown in the above-described cross-sectional photograph, the first connection portion 121 and the second connection portion 131 can have a shape substantially parallel to the thickness direction (T-axis direction), the first band portion 123 and the second band portion 133 can have a shape substantially parallel to the length direction (L-axis direction), and the first corner portion 125 and the second corner portion 135 can have a curved shape. The above-described curved shape may be a curved shape having a tangent whose inclination changes from a direction parallel to the thickness direction (T-axis direction) to a direction parallel to the length direction (L-axis direction) (or in the opposite direction).
[0074] The first external electrode 120 can include a first electrode layer 210, a first conductive carbon layer 220, a first metal layer 230, and a first plating layer 240, and the second external electrode 130 can include a second electrode layer 310, a second conductive carbon layer 320, a second metal layer 330, and a second plating layer 340.
[0075] The first external electrode 120 can include a first electrode layer 210, a first conductive carbon layer 220, a first metal layer 230, and a first plating layer 240.
[0076] The first electrode layer 210 is disposed on the first surface S1 of the ceramic body 110 and is connected to and electrically coupled with the exposed ends of the plurality of first internal electrodes 150. The first electrode layer 210 does not extend from the first surface S1 of the ceramic body 110 to other surfaces. That is, the first electrode layer 210 is not disposed on the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110.
[0077] The first electrode layer 210 can include a conductive metal and glass. The first electrode layer 210 can include, for example, one or more of silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and alloys thereof.
[0078] The first electrode layer 210 may be a sintered electrode including a conductive metal and glass. The first electrode layer 210 can be formed by dipping the first surface S1 of the ceramic body 110 into a slurry containing a conductive metal and glass and then firing. Alternatively, the first electrode layer 210 can also be formed by transferring a sheet containing a conductive metal and glass to the ceramic body 110.
[0079] The first electrode layer 210 can include a first base layer 211 and a second base layer 213.
[0080] The first base layer 211 can be directly connected to the plurality of first internal electrodes 150. The first base layer 211 can include, for example, a conductive metal and glass. The conductive metal can include nickel (Ni).
[0081] The second base layer 213 can be disposed on the first base layer 211. The second base layer 213 can include, for example, a conductive metal and glass. The conductive metal can include copper (Cu).
[0082] The first conductive carbon layer 220 is disposed on the first electrode layer 210. For example, the first conductive carbon layer 220 can cover the first electrode layer 210.
[0083] The first conductive carbon layer 220 can include a conductive carbon material. For example, the first conductive carbon layer 220 can include one or more of graphite, graphene, carbon nanotube, fullerene, and carbon black.
[0084] As an example, after partially dipping the ceramic body into a dispersion liquid containing a conductive carbon material and coating it according to the dilution degree of the solution, and then heat-drying and curing at 170 °C for 10 minutes, a solid-phase conductive carbon layer can be formed with a thickness of approximately 0.05 μm or more and 20 μm or less. Here, by setting the dilution ratio so that the content of the solid contents of the solution containing the conductive carbon material is approximately 1 wt% or more and 20 wt%, and by adjusting the number of repetitions of the dipping and drying process, the thickness of the conductive carbon layer can be adjusted.
[0085] Different from this embodiment, the first electrode layer 210 may not be disposed on the first surface S1 of the ceramic body 110, and the first conductive carbon layer 220 may be directly disposed on the first surface S1. However, in that case, if the end of the first internal electrode 150 protrudes short or there is an oxide film on the exposed surface of the first internal electrode 150, the electrical characteristics may deteriorate even if the first conductive carbon layer 220 and the first internal electrode 150 are connected.
[0086] On the contrary, according to this embodiment, after connecting the first electrode layer 210 containing a conductive metal to the first internal electrode 150, the first conductive carbon layer 220 is disposed on the first electrode layer 210, so the above-mentioned problems can be improved and the electrical characteristics can be sufficiently ensured.
[0087] The first metal layer 230 is disposed on the fifth surface S5 of the ceramic body 110.
[0088] The first metal layer 230 can cover a part of the fifth surface S5 at a point spaced apart from the center of the fifth surface S5 of the ceramic body 110 in the direction of the first surface S1. For example, the first metal layer 230 can cover a part of the fifth surface S5 by contacting the edges of the fifth surface S5 of the ceramic body 110 on the side of the first surface S1, the side of the third surface S3, and the side of the fourth surface S4.
[0089] The first metal layer 230 can be formed, for example, in the following manner.
[0090] After forming a sheet laminate by stacking ceramic green sheets having internal electrodes formed on their surfaces, a conductive paste is printed on the surface of the sheet laminate to form a metal pattern. For example, a conductive paste containing nickel (Ni), copper (Cu), a nickel (Ni) alloy, or a copper (Cu) alloy can be printed on the surface of the sheet laminate by screen printing or gravure printing to form a metal pattern. However, the present embodiment is not limited thereto. The sheet laminate with the metal pattern formed thereon is diced to produce green chips. In this dicing process, the metal pattern can be diced to become the first metal layer.
[0091] The edge of the first metal layer 230 on the side of the first surface S1 can be in contact with the first conductive carbon layer 220. Here, the first metal layer 230 and the first conductive carbon layer 220 can have a continuous interface. Therefore, the surface of the ceramic body 110 or the surface of the first electrode layer 210 may not be exposed between the first metal layer 230 and the first conductive carbon layer 220.
[0092] The interface between the first metal layer 230 and the first conductive carbon layer 220 may be present at the first corner 125 between the first surface S1 and the fifth surface S5 of the ceramic body 110, but is not limited thereto. For example, the boundary between the first metal layer 230 and the first conductive carbon layer 220 may be present on the interface between the first corner 125 and the fifth surface S5. However, since the first conductive carbon layer 220 is disposed on the first surface S1 of the ceramic body 110, the interface between the first metal layer 230 and the first conductive carbon layer 220 is not formed on the first surface S1 of the ceramic body 110.
[0093] Unlike this embodiment, when the first external electrode 120 does not include the first conductive carbon layer 220, a gap may occur between the first metal layer 230 and the first electrode layer 210. In particular, if the first electrode layer 210 is formed thinly, the possibility of the existence of a gap becomes even greater. If the first plating layer 240 is formed in a state where a gap exists between the first metal layer 230 and the first electrode layer 210, the connection between the first connection portion 121 and the first band portion 123 of the first external electrode 120 may be broken or become insufficient.
[0094] On the contrary, according to this embodiment, since the first conductive carbon layer 220 serves to connect the first metal layer 230 and the first electrode layer 210, even if a gap exists between the first metal layer 230 and the first electrode layer 210, sufficient connection between the first connection portion 121 and the first band portion 123 can be ensured.
[0095] The first conductive carbon layer 220 and the first metal layer 230 may be covered by the first plating layer 240. That is, the first conductive carbon layer 220 on the first surface S1 of the ceramic body 110 and the first metal layer 230 on the fifth surface S5 may be covered by the first plating layer 240 at once.
[0096] The first plating layer 240 can be formed by directly plating a conductive metal on the first conductive carbon layer 220 and the first metal layer 230. That is, the first conductive carbon layer 220 and the first metal layer 230 can serve as a plating seed layer. Here, the conductive metal can include, for example, nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb), either alone or as an alloy thereof, but the present embodiment is not limited thereto.
[0097] The first plating layer 240 can be composed of a plurality of layers. For example, the first plating layer 240 can include a first layer 241 that entirely covers the first conductive carbon layer 220 and the first metal layer 230, a second layer 243 that covers the first layer 241, and a third layer 245 that covers the second layer 243.
[0098] The first layer 241 can contain copper (Cu), the second layer 243 can contain nickel (Ni), and the third layer 245 can contain tin (Sn), but the present embodiment is not limited thereto.
[0099] The second external electrode 130 can include a second electrode layer 310, a second conductive carbon layer 320, a second metal layer 330, and a second plating layer 340. Except for its position, the structure and components of the second external electrode 130 are the same as those of the first external electrode 120, so repeated descriptions regarding the second external electrode 130 are omitted.
[0100] Referring to FIG. 4, after manufacturing a green chip by cutting a sheet laminate printed with a metal pattern and firing the green chip to form a first metal layer 230 on the fifth surface S5 of the ceramic body 110, the ceramic body 110 can be partially dipped into a slurry containing a conductive metal and glass and fired to form a first electrode layer 210 on the first surface S1 of the ceramic body 110. On the other hand, a first electrode layer 210 can also be formed by transferring a sheet containing a conductive metal (e.g., copper (Cu) or nickel (Ni)) onto the first surface S1 of the ceramic body 110. Thereafter, a first conductive carbon layer 220 can be formed so as to cover the first electrode layer 210. As an example, after partially dipping the ceramic body into a dispersion liquid containing a conductive carbon material and applying it according to the dilution degree of the solution, and then heat-drying and curing at 170° C. for 10 minutes, a solid-phase conductive carbon layer can be formed with a thickness of approximately 0.05 μm or more and 20 μm or less. Here, by setting the dilution ratio so that the content of the solid contents of the solution containing the conductive carbon material is approximately 1 wt% or more and 20 wt% level, and by adjusting the number of repetitions of the dipping and drying process, the thickness of the conductive carbon layer can be adjusted. Next, a first plating layer 240 can be formed by directly plating a conductive metal on the first conductive carbon layer 220 and the first metal layer 230. For example, copper (Cu) can be electrolytically plated to form the first plating layer 240. Here, the first conductive carbon layer 220 and the first metal layer 230 can serve as a plating seed layer. Since the first conductive carbon layer 220 is disposed on the first surface S1 of the ceramic body 110 and the first metal layer 230 is disposed on the fifth surface S5, the first plating layer 240 is not formed on the third surface S3, the fourth surface S4, and the sixth surface S6 of the ceramic body 110. Eventually, the first external electrode 120 and the second external electrode 130 are not disposed on the third surface S3, the fourth surface S4, and the sixth surface S6 of the ceramic body 110.
[0101] In this embodiment, since the first external electrode 120 is not disposed on the third surface S3 and the fourth surface S4 of the ceramic body 110, the width of the ceramic body 110 can be increased accordingly. Also, since the first external electrode 120 is not disposed on the sixth surface S6 of the ceramic body 110, the thickness of the ceramic body 110 can be increased accordingly. If the width of the ceramic body 110 increases, the width of the internal electrode that affects the capacitance can also be increased accordingly. If the thickness of the ceramic body 110 increases, the number of stacked internal electrodes can also be increased. Therefore, the capacitance of the multilayer ceramic capacitor can be increased.
[0102] 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.
Explanation of Reference Numerals
[0103] 1000: Multilayer ceramic capacitor 110: Ceramic body 120: First external electrode 121: First connection portion 123: First band portion 125: First corner 130: Second external electrode 131: Second connection portion 133: Second band portion 135: Second corner 140: Dielectric layer 143: First cover layer 145: Second cover layer 150: First internal electrode 160: Second internal electrode 210: First electrode layer 220: First conductive carbon layer 230: First metal layer 240: First plating layer 310: Second electrode layer 320: Second conductive carbon layer 330: Second metal layer 340: Second plating layer
Claims
1. a ceramic body including a first surface and a second surface facing each other in a first direction, a third surface and a fourth surface facing each other in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface facing each other in a third direction and connecting the first surface and the second surface; a plurality of first internal electrodes and a plurality of second internal electrodes disposed within the ceramic body; a first external electrode disposed outside the ceramic body and connected to the first internal electrodes; and a second external electrode disposed outside the ceramic body and connected to the second internal electrodes; the first external electrode includes a first electrode layer disposed on the first surface and electrically connected to the plurality of first internal electrodes, a first conductive carbon layer disposed on the first electrode layer, and a first metal layer disposed on the fifth surface and in contact with the first conductive carbon layer between the first surface and the fifth surface; the second external electrode includes a second electrode layer disposed on the second surface and electrically connected to the plurality of second internal electrodes, a second conductive carbon layer disposed on the second electrode layer, and a second metal layer disposed on the fifth surface and in contact with the second conductive carbon layer between the second surface and the fifth surface.
2. 2. The multilayer ceramic capacitor of claim 1, wherein the first conductive carbon layer and the second conductive carbon layer include at least one of graphite, graphene, carbon nanotube, fullerene, and carbon black.
3. the first electrode layer includes a conductive metal and a glass; The multilayer ceramic capacitor of claim 1 , wherein the second electrode layer comprises a conductive metal and a glass.
4. The multilayer ceramic capacitor according to claim 3 , wherein the conductive metal of the first electrode layer and the conductive metal of the second electrode layer include nickel (Ni).
5. the first electrode layer includes a first base layer connected to the first internal electrodes and a second base layer disposed on the first base layer; The multilayer ceramic capacitor of claim 1 , wherein the second electrode layer includes a third base layer connected to the second internal electrodes and a fourth base layer disposed on the third base layer.
6. the first base layer and the second base layer include a conductive metal and a glass; The multilayer ceramic capacitor of claim 5 , wherein the third and fourth base layers comprise a conductive metal and a glass.
7. The multilayer ceramic capacitor of claim 6 , wherein the conductive metal of the first base layer and the conductive metal of the third base layer include nickel (Ni).
8. The multilayer ceramic capacitor according to claim 6 , wherein the conductive metal of the second base layer and the conductive metal of the fourth base layer comprise copper (Cu).
9. the first external electrode further includes a first plating layer covering the first metal layer and the first conductive carbon layer, The multilayer ceramic capacitor of claim 1 , wherein the second external electrode further comprises a second plating layer covering the second metal layer and the second conductive carbon layer.
10. The first plating layer is a first layer covering the first metal layer and the first conductive carbon layer; a second layer overlying the first layer; and The multilayer ceramic capacitor of claim 9 , further comprising a third layer covering the second layer.
11. the first layer comprises copper (Cu); the second layer comprises nickel (Ni); The multilayer ceramic capacitor of claim 10 , wherein the third layer comprises tin (Sn).
12. The second plating layer is a first layer covering the second metal layer and the second conductive carbon layer; a second layer overlying the first layer; and The multilayer ceramic capacitor of claim 9 , further comprising a third layer covering the second layer.
13. the first layer comprises copper (Cu); the second layer comprises nickel (Ni); The multilayer ceramic capacitor of claim 12 , wherein the third layer comprises tin (Sn).