Multilayer ceramic capacitor

Abstract

To provide a multilayer ceramic capacitor including external electrodes having improved bending strength and well-formed plating layers.SOLUTION: A multilayer ceramic capacitor 1000 includes internal electrodes 150, 160 and external electrodes 120, 130. The external electrodes include end surface portions 125, 135 electrically connected to the internal electrodes, side surface portions 127, 137 extending to adjacent surfaces thereof, and conductive resin layers 123, 133 covering portions of the side surface portions, the conductive resin layer includes tin (Sn) and bismuth (Bi).SELECTED DRAWING: Figure 2

Description

Technical Field

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

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, having a 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 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 an internal electrode disposed inside the ceramic body and an external electrode disposed outside the ceramic body and connected to the internal electrode. The external electrode may include an electrode layer and a conductive resin layer covering the electrode layer. When the bending strength of the external electrode is insufficient or the plating layer is not sufficiently formed on the external electrode, the moisture resistance reliability may deteriorate due to moisture penetration.

Summary of the Invention

Problems to be Solved by the Invention

[0005] One aspect of the embodiment is to provide a multilayer ceramic capacitor including an external electrode with improved bending strength and a well-formed plating layer.

[0006] 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

[0007] 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, and a first external electrode and a second external electrode disposed outside the ceramic body. The first external electrode includes a first end face portion disposed on the first surface and electrically connected to the plurality of first internal electrodes, a first side face portion extending from the first end face portion to at least one of the third surface, the fourth surface, the fifth surface, and the sixth surface, and a first conductive resin layer covering at least a part of the first side face portion. The second external electrode includes a second end face portion disposed on the second surface and electrically connected to the plurality of second internal electrodes, a second side face portion extending from the second end face portion to at least one of the third surface, the fourth surface, the fifth surface, and the sixth surface, and a second conductive resin layer covering at least a part of the second side face portion. The first conductive resin layer and the second conductive resin layer can include tin (Sn) and bismuth (Bi).

[0008] Further, the first conductive resin layer can entirely cover the first side face portion, and the second conductive resin layer can entirely cover the second side face portion.

[0009] Further, the length of the first conductive resin layer may be greater than the length of the first side face portion, and the length of the second conductive resin layer may be greater than the length of the second side face portion.

[0010] Further, the first conductive resin layer can include a first conductive connection portion containing an intermetallic compound and resin, and the second conductive resin layer can include a second conductive connection portion containing an intermetallic compound and resin.

[0011] Further, the first conductive connection portion contains tin (Sn) in an amount of 36 wt% or more and 50.4 wt% or less, and bismuth (Bi) in an amount of 14 wt% or more and 19.6 wt% or less, and the second conductive connection portion can contain tin (Sn) in an amount of 36 wt% or more and 50.4 wt% or less, and bismuth (Bi) in an amount of 14 wt% or more and 19.6 wt% or less.

[0012] Further, the intermetallic compound contained in the first conductive resin layer and the intermetallic compound contained in the second conductive resin layer can contain at least one of Cu6Sn5, Cu3Sn, Ni3Sn, and Ag3Sn.

[0013] Further, the first external electrode contains an intermetallic compound and further includes a first interface layer disposed between the first conductive resin layer and the first side surface portion, and the second external electrode contains an intermetallic compound and can further include a second interface layer disposed between the second conductive resin layer and the second side surface portion.

[0014] Further, the intermetallic compound contained in the first interface layer and the intermetallic compound contained in the second interface layer can contain Cu3Sn.

[0015] Further, the multilayer ceramic capacitor can further include a first plating layer covering the first external electrode and a second plating layer covering the second external electrode.

[0016] Further, the first plating layer includes a first layer disposed on the first external electrode and a second layer disposed on the first layer, and the second plating layer can include a third layer disposed on the second external electrode and a fourth layer disposed on the third layer.

[0017] Further, the first layer and the third layer may contain nickel (Ni), and the second layer and the fourth layer may contain tin (Sn).

[0018] Further, the multilayer ceramic capacitor may further include a third conductive resin layer discontinuously disposed between the first end face portion and the first plating layer, and a fourth conductive resin layer discontinuously disposed between the second end face portion and the second plating layer.

Advantages of the Invention

[0019] According to the multilayer ceramic capacitor according to the embodiment, the moisture resistance reliability can be improved by improving the bending strength of the external electrode and forming a good plating layer.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10a

Figure 10b

Best Mode for Carrying Out the Invention

[0021] 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 unnecessary for explanation are omitted in order to clearly explain the present invention, 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.

[0022] 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 must be understood that all modifications, equivalents, and alternatives included in the idea and technical scope of the present invention are included.

[0023] 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.

[0024] Also, when a part such as a layer, film, region, or plate 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.

[0025] 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.

[0026] Also, throughout the specification, when it is said "on a plane", this means when looking at the target part from above, and when it is said "in a cross-section", this means when looking at the cross-section obtained by vertically cutting the target part from the side.

[0027] Also, throughout the specification, when it is said "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 integral although referred to by different names depending on their position or function.

[0028] 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, and FIG. 3 is an exploded perspective view showing the laminated structure of internal electrodes in the multilayer ceramic capacitor of FIG. 1.

[0029] Referring to FIGS. 1, 2, and 3, the multilayer ceramic capacitor 1000 according to the present 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.

[0030] First, in order to clearly explain the present embodiment, if directions are defined, the L-axis, W-axis, and T-axis shown in the drawings respectively refer to the axes indicating the length direction, width direction, and thickness direction of the multilayer ceramic capacitor 1000.

[0031] 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.

[0032] 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.

[0033] 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) at the same time.

[0034] The ceramic body 110 can be formed in a substantially hexahedral shape, but the present embodiment is not limited thereto. Due to shrinkage during sintering, the ceramic body 110 is not a perfect hexahedral shape, but can have a substantially hexahedral shape. For example, the ceramic body 110 is substantially a straight hexahedral shape, but the portions corresponding to corners and vertices can have a rounded shape.

[0035] In the present embodiment, for the sake of 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 connecting the first surface S1 and the second surface S2 while facing each other in the width direction (W-axis direction) are defined as the third surface S3 and the fourth surface S4, and the surfaces connecting the first surface S1 and the second surface S2 while facing each other in the thickness direction (T-axis direction) are defined as the fifth surface S5 and the sixth surface S6.

[0036] Therefore, the first direction, which is the 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.

[0037] The length of the ceramic body 110 can be based on a photograph taken by an optical microscope or a scanning electron microscope (SEM) 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. It can mean 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 aforementioned 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 aforementioned 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 aforementioned cross-sectional photograph respectively.

[0038] 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 center 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.

[0039] 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 center 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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 for the length-thickness (T-axis direction) cross section at the center in the width direction (W-axis direction) of the ceramic body 110. It may be the arithmetic mean value of the thicknesses of one internal electrode shown in the aforementioned cross-sectional photograph 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.

[0047] 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).

[0048] 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.

[0049] The first cover layer 143 and the second cover layer 145 can be disposed outside the active region in the thickness direction (T-axis direction).

[0050] The first cover layer 143 is disposed between the fifth surface S5 of the ceramic body 110 and the internal electrode closest thereto. The second cover layer 145 is disposed between the sixth surface S6 of the ceramic body 110 and the internal electrode closest thereto.

[0051] That is, the first cover layer 143 can be disposed above the uppermost internal electrode in the ceramic body 110, and the second cover layer 145 can be disposed 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.

[0052] The first cover layer 143 and the second cover layer 145 can serve to prevent damage to the first internal electrode 150 and the second internal electrode 160 due to physical or chemical stress.

[0053] 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, 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.

[0054] 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) or aluminum (Al), etc.

[0055] 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.

[0056] The first external electrode 120 and the second external electrode 130 are disposed outside the ceramic body 110.

[0057] The first external electrode 120 is disposed on the first surface S1 of the ceramic body 110 and can extend to the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6. The second external electrode 130 is disposed on the second surface S2 of the ceramic body 110 and can extend to the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6.

[0058] The first external electrode 120 includes a first electrode layer 121 and a first conductive resin layer 123.

[0059] The first electrode layer 121 contains a conductive metal. The first electrode layer 121 can include, for example, one or more of silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and alloys thereof.

[0060] The first electrode layer 121 includes a first end face portion 125 and a first side face portion 127.

[0061] The first end face portion 125 covers the first surface S1 of the ceramic body 110 and is a portion connected to and electrically connected to the exposed ends of the plurality of first internal electrodes 150.

[0062] The first side face portion 127 extends from the first end face portion 125 and covers a part of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110.

[0063] The first electrode layer 121 may be a sintered electrode containing a conductive metal and glass. The first electrode layer 121 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 121 can also be formed by transferring a sheet containing a conductive metal and glass to the ceramic body 110.

[0064] The first conductive resin layer 123 covers the first side face portion 127 and covers a part of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110.

[0065] For example, the first conductive resin layer 123 can cover the entire first side face portion 127.

[0066] Further, the length of the first conductive resin layer 123 may be greater than the length of the first side surface portion 127. Here, the length of the first conductive resin layer 123 and the length of the first side surface portion 127 are measured 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. The length of the first conductive resin layer 123 can mean 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 each other in the length direction (L-axis direction) of the first conductive resin layer 123 shown in the above cross-sectional photograph. Also, the length of the first side surface portion 127 can mean 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 each other in the length direction (L-axis direction) of the first side surface portion 127 shown in the above cross-sectional photograph.

[0067] The first conductive resin layer 123 can include a first conductive connection portion 123a containing an intermetallic compound and a resin 123b.

[0068] The resin 123b contained in the first conductive resin layer 123 may be various known thermosetting resins such as, for example, an epoxy resin, a phenol resin, a urethane resin, a silicon resin, or a polyimide resin.

[0069] On the other hand, the first conductive resin layer 123 can include a conductive metal as a filler. For example, the filler can include copper (Cu), silver (Ag), nickel (Ni), tin (Sn), or an alloy thereof.

[0070] An intermetallic compound means a compound in which two or more metals are combined in a simple integer ratio. The intermetallic compound is at least one of copper (Cu), silver (Ag), copper (Cu) coated with silver (Ag), copper (Cu) coated with tin (Sn), and nickel (Ni), which are high melting point metals contained in the conductive resin composition for forming the first conductive resin layer 123, and at least one of tin (Sn), a tin (Sn) alloy, bismuth (Bi), or a bismuth (Bi) alloy, which are low melting point metals, can react with each other to form. The intermetallic compound thus formed can contain at least one of Cu6Sn5, Cu3Sn, Ni3Sn, and Ag3Sn. Bismuth (Bi) does not directly form an intermetallic compound, but can play a role in further lowering the melting point of tin (Sn) during the intermetallic compound formation process. That is, the melting point of tin (Sn) will decrease as the content of bismuth (Bi) increases. On the other hand, the low melting point metal remaining after the formation of the intermetallic compound and the intermetallic compound are included in the first conductive connection portion 123a. That is, the first conductive connection portion 123a can contain a low melting point metal having a melting point lower than the curing temperature of the resin 123b. For example, the low melting point metal can have a melting point of 300 °C or lower, and more specifically, can have a melting point of 200 °C to 250 °C.

[0071] In addition, the first conductive connection portion 123a can contain tin (Sn) at 36 wt% or more and 50.4 wt% or less, and bismuth (Bi) at 14 wt% or more and 19.6 wt% or less. The balance may be, for example, copper (Cu).

[0072] When the tin (Sn) content is less than 36 wt% and the bismuth (Bi) content is less than 14 wt%, or when the tin (Sn) content exceeds 50.4 wt% and the bismuth (Bi) content exceeds 19.6 wt%, the intermetallic compound may not be sufficiently formed, or the connectivity of the intermetallic compound may be low and the plating layer may be inadequately formed. For example, a plating break phenomenon may occur.

[0073] Here, the contents of tin (Sn) and bismuth (Bi) can be confirmed through EDAX (Energy Dispersive x-ray Spectroscopy) elemental analysis.

[0074] After the first electrode layer 121 is formed, a conductive resin composition containing metal powder and a thermosetting resin can be applied onto the first electrode layer 121. Here, the thermosetting resin may be a resin with a small molecular weight and in a liquid state at room temperature among bisphenol A resin, glycol epoxy resin, novolak epoxy resin or their derivatives, but is not limited thereto. For example, the conductive resin composition can be manufactured by mixing silver (Ag) powder, copper (Cu) powder, copper (Cu) powder coated with silver (Ag), tin (Sn)-based solder powder and a thermosetting resin, and then dispersing them using a 3-roll mill. The tin (Sn)-based solder powder can contain at least any one of tin (Sn), Sn 96.5 Ag 3.0 Cu 0.5 、Sn 42 Bi 58 、and Sn 72 Bi 28 but the present disclosure is not limited thereto. Then, after removing the conductive resin composition on the first end surface portion 125, the first conductive resin layer 123 on the first side surface portion 127 can be formed through a curing heat treatment. Therefore, the first end surface portion 125 is disposed on the first surface S1 of the ceramic body 110, and the first side surface portion 127 and the first conductive resin layer 123 are disposed on the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6.

[0075] Unlike this embodiment, when the electrode layer and the resin layer covering it are both disposed on the first surface S1 of the ceramic body 110, since the resin layer has lower electrical connectivity than the electrode layer, there may arise a problem that the equivalent series resistance (ESR) of the first external electrode increases. During the high-temperature reflow process, there may also be a risk of lifting due to out-gassing from the resin layer. Further, since the resin layer exists on the electrode layer, compared to the case where only the electrode layer exists, the thickness of the external electrode is thicker and the relative volume of the ceramic body is smaller, so there is a problem that the effective capacitance of the multilayer ceramic capacitor decreases.

[0076] On the contrary, according to this embodiment, since the first end face portion 125 is disposed on the first surface S1 of the ceramic body 110, and the first side face portion 127 and the first conductive resin layer 123 are not disposed on the first surface S1, the above-described problems may not occur.

[0077] The second external electrode 130 includes a second electrode layer 131 and a second conductive resin layer 133.

[0078] The second electrode layer 131 contains a conductive metal. The second electrode layer 131 can include, for example, one or more of silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and alloys thereof.

[0079] The second electrode layer 131 includes a second end face portion 135 and a second side face portion 137.

[0080] The second end face portion 135 covers the second surface S2 of the ceramic body 110 and is a portion connected to and electrically connected to the exposed ends of the plurality of second internal electrodes 160.

[0081] The second side face portion 137 extends from the second end face portion 135 and covers a part of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110.

[0082] The second conductive resin layer 133 covers the second side surface portion 137 and covers a part of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110.

[0083] Since the second external electrode 130 corresponds to the structure, material, and function of the first external electrode 120 except for its position, repeated descriptions thereof are omitted.

[0084] On the other hand, the multilayer ceramic capacitor 1000 can further include a first plating layer 180 and a second plating layer 190.

[0085] The first plating layer 180 covers the first external electrode 120. The first plating layer 180 can include a first layer 181 and a second layer 183. The first layer 181 is disposed on the first external electrode 120, and the second layer 183 is disposed on the first layer 181. The first layer 181 contains nickel (Ni), and the second layer 183 can contain tin (Sn), but the present embodiment is not limited thereto.

[0086] The second plating layer 190 covers the second external electrode 130. The second plating layer 190 can include a first layer 191 and a second layer 193. The first layer 191 is disposed on the second external electrode 130, and the second layer 193 is disposed on the first layer 191. The first layer 191 contains nickel (Ni), and the second layer 193 can contain tin (Sn), but the present embodiment is not limited thereto.

[0087] On the other hand, FIG. 5 is a diagram schematically showing the A region according to another embodiment.

[0088] Referring to FIG. 5, the first conductive resin layer 123 can further include a plurality of metal particles 123c. The plurality of metal particles 123c can include one or more of silver (Ag), copper (Cu), copper (Cu) coated with tin (Sn), copper (Cu) coated with silver (Ag), and nickel (Ni). The plurality of metal particles 123c may be metal particles that remain after reacting with a low-melting-point metal having a melting point lower than the curing temperature of the resin 123b in the curing heat treatment step of the first conductive resin layer 123 to form an intermetallic compound. The metal powder contained in the conductive resin composition for forming the first conductive resin layer 123 can react with most of the tin (Sn)-based solder powder to form the first conductive connection portion 123a, thereby preventing the lifting between the first side surface portion 127 and the first conductive resin layer 123.

[0089] On the other hand, FIG. 6 is a diagram schematically showing the A region according to another embodiment.

[0090] Referring to FIG. 6, a first interface layer 129 is disposed between the first side surface portion 127 and the first conductive resin layer 123. The first interface layer 129 can include an intermetallic compound. The intermetallic compound contained in the first interface layer 129 can include Cu3Sn. The first interface layer 129 can be formed by the mutual reaction of copper (Cu) contained in the first electrode layer 121 and tin (Sn) or a tin (Sn) alloy contained in the first conductive resin layer 123 in the process of applying, drying, and curing heat-treating the conductive resin composition to form the first conductive resin layer 123, but the present disclosure is not limited thereto.

[0091] The first interface layer 129 can connect the first conductive connection portion 123a of the first side surface portion 127 and the first conductive resin layer 123. The first interface layer 129 can ensure excellent mechanical and electrical connectivity between the first side surface portion 127 and the first conductive resin layer 123. For example, the first interface layer 129 can be formed in a plurality of island forms, and the plurality of islands can also form a layer.

[0092] FIG. 7 is a cross-sectional view schematically showing a multilayer ceramic capacitor according to another embodiment.

[0093] Referring to FIG. 7, the multilayer ceramic capacitor 2000 can include a third conductive resin layer 124 and a fourth conductive resin layer 134. The third conductive resin layer 124 is discontinuously disposed between the first end face portion 125 of the first electrode layer 121 and the first plating layer 180, and the fourth conductive resin layer 134 is discontinuously disposed between the second end face portion 135 of the second electrode layer 131 and the second plating layer 190. The third conductive resin layer 124 and the fourth conductive resin layer 134 are arranged in a plurality of island forms.

[0094] As described in connection with the multilayer ceramic capacitor shown in FIG. 1, after removing the conductive resin composition applied to the first end face portion 125 and the second end face portion 135, the first conductive resin layer 123 on the first side face portion 127 and the second conductive resin layer 133 on the second side face portion 137 are formed through a curing heat treatment. If the conductive resin composition on the first end face portion 125 and the second end face portion 135 is not completely removed, this conductive resin composition can be cured to form the third conductive resin layer 124 and the fourth conductive resin layer 134.

[0095] Since the third conductive resin layer 124 is discontinuously disposed, the first end face portion 125 of the first electrode layer 121 and the first layer 181 of the first plating layer 180 may also be in discontinuous contact. Since the fourth conductive resin layer 134 is discontinuously disposed, the second end face portion 135 of the second electrode layer 131 and the first layer 191 of the second plating layer 190 may also be in discontinuous contact.

[0096] Since the remaining components except for the above are the same as those of the multilayer ceramic capacitor shown in FIG. 1, the repeated description thereof is omitted.

[0097] Hereinafter, specific examples of the present disclosure are presented. However, the examples described below are merely for specifically exemplifying or explaining the invention, and the scope of the invention should not be limited thereby.

Example

[0098] [Manufacturing Example 1: Manufacturing of Multilayer Ceramic Capacitor] After applying a paste containing barium titanate (BaTiO3) powder onto a carrier film and drying it, a plurality of dielectric green sheets are manufactured.

[0099] A conductive paste containing nickel (Ni) is applied onto the dielectric green sheet using screen printing to form a conductive paste layer.

[0100] A plurality of dielectric green sheets are laminated so that at least a part of the conductive paste layers overlap with each other to manufacture a dielectric green sheet laminate.

[0101] After cutting the dielectric green sheet laminate into the form of individual chips, it is maintained at 350 °C for 66 hours in an air atmosphere to remove the binder, and then fired at 1165 °C to manufacture a ceramic body.

[0102] A paste containing glass frit and copper (Cu) is applied onto the outer surface of the ceramic body by dipping and dried, and then sintered to form an electrode layer.

[0103] The ceramic body is dipped into a conductive resin composition containing an epoxy resin and tin (Sn), bismuth (Bi), and copper (Cu). Here, the contents of tin (Sn), bismuth (Bi), and copper (Cu) in the conductive resin layer of the external electrode in the examples and comparative examples are adjusted as shown in Table 1.

[0104] After removing the conductive resin composition from the first and second surfaces of the ceramic body using a porous nonwoven fabric and curing it, a conductive resin layer is formed.

[0105] Thereafter, nickel (Ni) and tin (Sn) plating are performed, and heat treatment is carried out at 160 °C for 1 hour to manufacture a multilayer ceramic capacitor.

[0106]

Table 1

[0107] (Experimental Example 1) The failure rates due to peeling of the external electrodes of the multilayer ceramic capacitors manufactured in the examples and comparative examples were confirmed, and the results are shown in Table 2.

[0108]

Table 2

[0109] Referring to Table 2, no peeling phenomenon occurred in the multilayer ceramic capacitors according to Examples 1 to 3, but the peeling phenomenon occurred in the multilayer ceramic capacitors according to Comparative Examples 1 to 6 at 5% or more and 31% or less. This is because more intermetallic compounds were formed in the examples and the connectivity of the intermetallic compounds was also excellent compared to the comparative examples.

[0110] [Manufacturing Example 2: Manufacturing of Multilayer Ceramic Capacitor] (Example 4) Manufacture a multilayer ceramic capacitor according to Manufacturing Example 1, but the contents of tin (Sn), bismuth (Bi), and copper (Cu) are the same as in Example 1.

[0111] (Comparative Example 7) After applying a paste containing barium titanate (BaTiO3) powder on a carrier film and drying it, a plurality of dielectric green sheets are manufactured.

[0112] Apply a conductive paste containing nickel (Ni) on the dielectric green sheet using screen printing to form a conductive paste layer.

[0113] Manufacture a dielectric green sheet laminate by laminating a plurality of dielectric green sheets while at least a part of the conductive paste layers overlaps.

[0114] After cutting the dielectric green sheet laminate into the form of individual chips, it is debound by maintaining it at 350°C for 66 hours in an air atmosphere, and then fired at 1165°C to manufacture a ceramic body.

[0115] A paste containing glass frit and copper (Cu) is applied to the outer surface of the ceramic body by dipping and dried, and then sintered to form an electrode layer.

[0116] The ceramic body is dipped into a conductive resin composition containing an epoxy resin and tin (Sn), bismuth (Bi), and copper (Cu). Here, the contents of tin (Sn), bismuth (Bi), and copper (Cu) are adjusted to be the same as in Example 4.

[0117] The conductive resin composition is post-cured to form a conductive resin layer.

[0118] Thereafter, nickel (Ni) and tin (Sn) plating are performed to manufacture a multilayer ceramic capacitor.

[0119] [Experimental Example: Performance of Multilayer Ceramic Capacitor] (Experimental Example 2) Measure the moisture resistance of the multilayer ceramic capacitors manufactured in Example 4 and Comparative Example 7.

[0120] Using a stencil mask, solder cream is patterned on a 40-channel PCB board dedicated to moisture resistance characteristics. Then, the prepared test pieces are mounted on the PCB board after performing a reflow process at a maximum temperature of 260°C. The prepared PCB board is mounted in a slot capable of measuring potential difference and current and then inserted into a chamber at a temperature of 85°C and a humidity of 60%RH. Then, the moisture resistance was measured by confirming the level at which the insulation resistance (IR) decreases in the first and second steps of applying a potential difference of 7.56V across the test piece for 1 hour and the third step of applying a potential difference of 4.5V across the test piece for 2 hours. The results are shown in Table 3.

[0121]

Table 3

[0122] Referring to Table 3, the insulation resistance of the multilayer ceramic capacitor manufactured in Comparative Example 7 dropped to 10 7 Ω in the third step, while the insulation resistance of the multilayer ceramic capacitor manufactured in Example 4 maintained 109Ω in the third step, indicating excellent moisture resistance.

[0123] (Experimental Example 3) The results of measuring the equivalent series resistance of the multilayer ceramic capacitors manufactured in Example 4 and Comparative Example 7 are shown in FIG. 8.

[0124] Referring to FIG. 8, the equivalent series resistance (ESR) of the multilayer ceramic capacitor manufactured according to Example 4 is on average 1.55 mΩ, and the equivalent series resistance (ESR) of the multilayer ceramic capacitor manufactured according to Comparative Example 7 is on average 3.26 mΩ. That is, the equivalent series resistance of Example 4 was shown to be lower than that of Comparative Example 7. This is because the electrical connectivity was improved by forming the plating layer immediately without disposing the resin layer on the electrode layers on the first and second surfaces of the ceramic body.

[0125] (Experimental Example 4) Using the bending test method shown in FIG. 9, the crack occurrence frequency of the ceramic body of the multilayer ceramic capacitors manufactured according to Example 4 and Comparative Example 7 was tested.

[0126] Referring to FIG. 9, the multilayer ceramic capacitor mounted on the substrate is placed in a device capable of pressing its mounting surface, and the opposite surface of the mounting surface in the multilayer ceramic capacitor is pressed down by 3 mm to check whether bending cracks occur, and the crack occurrence frequency can be measured.

[0127] In the 3 mm bending strength test, no crack defects in which the ceramic body cracked occurred in any of the 30 samples in Example 4 and Comparative Example 7.

[0128] Thus, the multilayer ceramic capacitor according to Example 4 exhibited a bending strength equivalent to that of Comparative Example 7.

[0129] (Experimental Example 5) FIG. 10a is an X-ray photograph for confirming the occurrence of lifting after reflow of the multilayer ceramic capacitor according to Example 4, and FIG. 10b is an X-ray photograph for confirming the occurrence of lifting after reflow of the multilayer ceramic capacitor according to Comparative Example 7.

[0130] In Example 4 and Comparative Example 7, the lifting phenomenon did not occur in any of the 40 samples after reflow. Thus, the multilayer ceramic capacitor according to Example 4 exhibited a level equivalent to that of Comparative Example 7.

[0131] 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 accompanying drawings, and it is natural that this also belongs to the scope of the present invention.

Explanation of Reference Numerals

[0132] 1000: Multilayer Ceramic Capacitor 110: Ceramic Body 120: First External Electrode 121: First Electrode Layer 123: First Conductive Resin Layer 124: Third Conductive Resin Layer 125: First End Face Portion 127: First Side Face Portion 130: Second External Electrode 131: Second Electrode Layer 133: Second Conductive Resin Layer 134: Fourth Conductive Resin Layer 135: Second End Face Portion 137: Second Side Face Portion 140: Dielectric Layer 143: First Cover Layer 145: Second Cover Layer 150: First Internal Electrode 160: Second Internal Electrode 180: First Plating Layer 190: Second Plating Layer 181, 191: First Layer 183, 193: Second 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; and A first external electrode and a second external electrode are disposed outside the ceramic body. Including, the first external electrode includes a first end surface portion disposed on the first surface and electrically connected to the plurality of first internal electrodes, a first side surface portion extending from the first end surface portion to at least one of the third surface, the fourth surface, the fifth surface, and the sixth surface, and a first conductive resin layer covering at least a portion of the first side surface portion, the second external electrode includes a second end surface portion disposed on the second surface and electrically connected to the plurality of second internal electrodes, a second side surface portion extending from the second end surface portion to at least one of the third surface, the fourth surface, the fifth surface, and the sixth surface, and a second conductive resin layer covering at least a portion of the second side surface portion, The first conductive resin layer and the second conductive resin layer contain tin (Sn) and bismuth (Bi).

2. the first conductive resin layer covers the entire first side portion, The multilayer ceramic capacitor according to claim 1 , wherein the second conductive resin layer entirely covers the second side portion.

3. the length of the first conductive resin layer is greater than the length of the first side portion, The multilayer ceramic capacitor according to claim 2 , wherein the length of the second conductive resin layer is greater than the length of the second side portion.

4. the first conductive resin layer includes a first conductive connector including an intermetallic compound and a resin; The multilayer ceramic capacitor of claim 1 , wherein the second conductive resin layer comprises a second conductive connector including an intermetallic compound and a resin.

5. The first conductive connector contains tin (Sn) in an amount of 36 wt % to 50.4 wt % and bismuth (Bi) in an amount of 14 wt % to 19.6 wt %, 5. The multilayer ceramic capacitor of claim 4, wherein the second conductive connector contains 36 wt% to 50.4 wt% tin and 14 wt% to 19.6 wt% bismuth.

6. The intermetallic compound contained in the first conductive resin layer and the intermetallic compound contained in the second conductive resin layer are Cu. ６ Sn ５ , Cu ３ Sn, Ni ３ Sn, and Ag ３ The multilayer ceramic capacitor according to claim 4 , further comprising at least one of Sn.

7. the first external electrode further includes a first interface layer including an intermetallic compound and disposed between the first conductive resin layer and the first side portion; The multilayer ceramic capacitor according to claim 1 , wherein the second external electrode further comprises a second interface layer including an intermetallic compound and disposed between the second conductive resin layer and the second side portion.

8. The intermetallic compound contained in the first interface layer and the intermetallic compound contained in the second interface layer are Cu ３ The multilayer ceramic capacitor according to claim 7 , comprising Sn.

9. The multilayer ceramic capacitor of claim 1 , further comprising a first plating layer covering the first external electrodes and a second plating layer covering the second external electrodes.

10. the first plating layer includes a first layer disposed on the first external electrode and a second layer disposed on the first layer, The multilayer ceramic capacitor of claim 9 , wherein the second plating layer includes a third layer disposed on the second external electrode and a fourth layer disposed on the third layer.

11. the first layer and the third layer comprise nickel (Ni); The multilayer ceramic capacitor of claim 10 , wherein the second layer and the fourth layer comprise tin (Sn).

12. a third conductive resin layer discontinuously disposed between the first end surface portion and the first plating layer; and The multilayer ceramic capacitor according to claim 9 , further comprising a fourth conductive resin layer discontinuously disposed between the second end surface portion and the second plating layer.

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