Multilayer ceramic capacitor

Abstract

The present disclosure provides a multilayer ceramic capacitor. The multilayer ceramic capacitor includes: a ceramic body including a plurality of first internal electrodes and a plurality of second internal electrodes disposed inside the ceramic body; and first and second external electrodes disposed outside the ceramic body. The first external electrode includes: a first end portion electrically connected to the plurality of first internal electrodes; a first side portion extending from the first end portion; and a first conductive resin layer covering at least a portion of the first side portion, and the second external electrode includes: a second end portion electrically connected to the plurality of second internal electrodes; a second side portion extending from the second end portion; and a second conductive resin layer covering at least a portion of the second side portion, and wherein the first conductive resin layer and the second conductive resin layer include tin (Sn) and bismuth (Bi).

Description

Technical Field

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

[0002] Electronic components using ceramic materials include capacitors, inductors, piezoelectric elements, varistors, or thermistors. Among these ceramic electronic components, multilayer ceramic capacitors (MLCCs) can be used in various electronic devices due to their advantages of small size, high capacitance, and easy installation.

[0003] For example, a multilayer ceramic capacitor can be used as a chip capacitor mounted on a substrate of various electronic products (such as imaging devices (such as liquid crystal displays (LCDs), plasma display panels (PDPs), and organic light-emitting diodes (OLEDs)), computers, personal portable terminals, and smartphones) for charging or discharging therefrom.

[0004] A multilayer ceramic capacitor may include: an inner electrode disposed inside a ceramic body; and an outer electrode disposed outside the ceramic body and connected to the inner electrode. There may be a case where the outer electrode includes an electrode layer and a conductive resin layer covering the electrode layer. If the bending strength of the outer electrode is insufficient or if the plating is not properly formed on the outer electrode, the moisture-proof reliability may deteriorate due to moisture penetration. Summary of the Invention

[0005] The present disclosure provides a multilayer ceramic capacitor including an outer electrode having improved bending strength and a well-formed plating layer.

[0006] However, the problems to be solved by the present disclosure are not limited to the foregoing problems, and can be extended in various ways within the scope of the technical concept included in the present disclosure.

[0007] According to an embodiment, a multilayer ceramic capacitor includes: a ceramic body having a first surface and a second surface opposite to each other in a first direction, a third surface and a fourth surface opposite to each other in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface opposite to each other in a third direction and connecting the first surface, the second surface, the third surface and the fourth surface, and the ceramic body includes 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, wherein the first external electrode includes a first electrode layer and a first conductive resin layer, and the first electrode layer includes: a first end portion disposed on the first surface and electrically connected to the plurality of first internal electrodes; and a first side portion extending from the first end portion to at least one of the third surface, the fourth surface, the fifth surface and the sixth surface, and the first conductive resin layer covers at least a part of the first side portion, wherein the second external electrode includes a second electrode layer and a second conductive resin layer, and the second electrode layer includes: a second end portion disposed on the second surface and electrically connected to the plurality of second internal electrodes; and a second side portion extending from the second end portion to at least one of the third surface, the fourth surface, the fifth surface and the sixth surface; and the second conductive resin layer covers at least a part of the second side portion, and wherein the first conductive resin layer and the second conductive resin layer include tin (Sn) and bismuth (Bi).

[0008] The first conductive resin layer may completely cover the first side portion, and the second conductive resin layer may completely cover the second side portion.

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

[0010] The first conductive resin layer may include a resin and a first conductive connection portion including an intermetallic compound, and the second conductive resin layer may include the resin and a second conductive connection portion including the intermetallic compound.

[0011] The first conductive connection portion may include: tin (Sn) in an amount greater than or equal to 36 wt% and less than or equal to 50.4 wt%; and bismuth (Bi) in an amount greater than or equal to 14 wt% and less than or equal to 19.6 wt%, and the second conductive connection portion may include: tin (Sn) in an amount greater than or equal to 36 wt% and less than or equal to 50.4 wt%; and bismuth (Bi) in an amount greater than or equal to 14 wt% and less than or equal to 19.6 wt%.

[0012] The intermetallic compound included in the first conductive resin layer and the intermetallic compound included in the second conductive resin layer may include at least one of Cu6Sn5, Cu3Sn, Ni3Sn, and Ag3Sn.

[0013] The first external electrode may further include a first interface layer including an intermetallic compound and disposed between the first conductive resin layer and the first side portion, and the second external electrode may further include a second interface layer including the intermetallic compound and disposed between the second conductive resin layer and the second side portion.

[0014] The intermetallic compound included in the first interface layer and the intermetallic compound included in the second interface layer may include Cu3Sn.

[0015] The multilayer ceramic capacitor may further include: a first plating layer covering the first external electrode; and a second plating layer covering the second external electrode.

[0016] The first plating layer may include a first layer and a second layer, the first layer being disposed on the first external electrode and the second layer being disposed on the first layer, and the second plating layer may include a third layer and a fourth layer, the third layer being disposed on the second external electrode and the fourth layer being disposed on the third layer.

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

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

[0019] The first plating layer may contact the first end portion, and the second plating layer may contact the second end portion.

[0020] The first conductive resin layer may include a resin and a first conductive connection portion including an intermetallic compound, and the second conductive resin layer may include the resin and a second conductive connection portion including the intermetallic compound.

[0021] The first conductive connection portion may include: tin (Sn) in an amount greater than or equal to 36 wt% and less than or equal to 50.4 wt%, and bismuth (Bi) in an amount greater than or equal to 14 wt% and less than or equal to 19.6 wt%, and the second connection portion may include: tin (Sn) in an amount greater than or equal to 36 wt% and less than or equal to 50.4 wt%, and bismuth (Bi) in an amount greater than or equal to 14 wt% and less than or equal to 19.6 wt%.

[0022] The resin may include an epoxy resin.

[0023] The first end portion may include glass and a conductive metal.

[0024] According to an embodiment of the multilayer ceramic capacitor, moisture-proof reliability can be improved by improving the bending strength of the external electrode and forming a desired plating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a perspective view schematically showing a multilayer ceramic capacitor according to an embodiment.

[0026] Figure 2 is along Figure 1 A cross-sectional view of the multilayer ceramic capacitor taken along line II-II' in

[0027] Figure 3 is showing Figure 1 An exploded perspective view of the stacked structure of the internal electrodes in the multilayer ceramic capacitor of

[0028] Figure 4 is schematically showing Figure 2 Region A in

[0029] Figure 5 is a view schematically showing Region A according to another embodiment.

[0030] Figure 6 is a view schematically showing Region A according to another embodiment.

[0031] Figure 7 is schematically showing along Figure 1 A cross-sectional view of the multilayer ceramic capacitor taken along line II-II' according to another embodiment in

[0032] Figure 8 is a graph comparing the equivalent series resistance (ESR) of the multilayer ceramic capacitor according to an example and the multilayer ceramic capacitor according to a comparative example.

[0033] Figure 9 is a view showing a bending test method of the multilayer ceramic capacitor.

[0034] Figure 10A is an X-ray photograph for confirming whether warping occurs in the multilayer ceramic capacitor according to an example after reflow.

[0035] Figure 10B is an X-ray photograph for confirming whether warping occurs in the multilayer ceramic capacitor according to a comparative example after reflow. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the present disclosure will be described more fully with reference to the accompanying drawings, so that those of ordinary skill in the art can easily implement the embodiments of the present disclosure. To describe the present disclosure more clearly, parts irrelevant to the description may be omitted, and throughout this specification, the same or similar components may be denoted by the same reference numerals. In the drawings, some elements in the drawings are enlarged, omitted, or shown schematically, and the dimensions of each element do not fully reflect the actual dimensions.

[0037] The drawings of the present disclosure are intended to facilitate the understanding of the present disclosure and should not be construed as being limited to the drawings. In addition, the present disclosure is not limited to the specific disclosed form, but includes all variants, equivalents, and alternatives that do not depart from the scope and spirit of the present disclosure.

[0038] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0039] In addition, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "above" or "on" another element, the element may be directly above the other element, or there may also be intermediate elements therebetween. In contrast, when an element is referred to as being "directly on" another element, there are no intermediate elements. In addition, when an element is referred to as being "above" or "on" a reference part, it may mean that the element is located above or below the reference part, and it does not necessarily mean that the element is located above or on the reference part in the opposite direction of the gravitational direction.

[0040] Throughout the specification, terms such as "comprising" and "having" are intended to indicate the presence of the features, numbers, steps, operations, elements, components, and / or combinations thereof used in the following description, and thus it should be understood that the possibility of the presence or addition of one or more different features, numbers, steps, operations, elements, components, and / or combinations thereof is not excluded. Therefore, unless explicitly described to the contrary, the word "comprising" will be understood to imply the inclusion of other elements without excluding other elements.

[0041] Throughout the specification, "in a plan view" means observing the target element from above, and "in a cross-sectional view" means observing the vertically intercepted target element from the side.

[0042] In addition, throughout the specification, the term "connected" can not only mean that two or more elements are directly connected, but also mean that two or more elements are indirectly connected, physically connected, or electrically connected through other elements, or two or more elements are integrally formed, although they are denoted by different names according to their positions or functions.

[0043] Figure 1 is a perspective view schematically showing a multilayer ceramic capacitor according to an embodiment. Figure 2 is taken along Figure 1 a cross-sectional view of the multilayer ceramic capacitor taken along line II-II' in Figure 3 is a perspective exploded view showing Figure 1 the stacked structure of the internal electrodes in the multilayer ceramic capacitor of

[0044] Referring to Figure 1 , Figure 2 and Figure 3 , the multilayer ceramic capacitor 1000 according to the present embodiment includes a ceramic body 110, a first external electrode 120, and a second external electrode 130. The ceramic body 110 includes a plurality of first internal electrodes 150 and a plurality of second internal electrodes 160.

[0045] First, when defining directions to clearly describe the present embodiment, the L-axis direction, the W-axis direction, and the T-axis direction shown in the drawings respectively represent the length direction, the width direction, and the thickness direction of the multilayer ceramic capacitor 1000.

[0046] The thickness direction (T-axis direction) may be a direction perpendicular to the large surface (main surface) of the sheet-like component. For example, the thickness direction (T-axis direction) can be used as the same concept as the direction along which the stacked dielectric layer 140 extends.

[0047] The length direction (L-axis direction) is a direction parallel to the large surface (main surface) of the sheet-like component, and may be a direction intersecting (or perpendicular) to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be the direction along which the first external electrode 120 and the second external electrode 130 face each other.

[0048] The width direction (W-axis direction) is a direction parallel to the large surface (main surface) of the sheet-like component and may be a direction intersecting (or perpendicular) to both the thickness direction (T-axis direction) and the length direction (L-axis direction) simultaneously.

[0049] The ceramic body 110 may have a generally hexahedral shape, but the present embodiment is not limited thereto. Due to the shrinkage of the ceramic body 110 during sintering, the ceramic body 110 may not have a completely hexahedral shape, but may have a generally hexahedral shape. For example, the ceramic body 110 may have a generally rectangular parallelepiped shape, but the portions corresponding to the corners or vertices may have a rounded shape.

[0050] In the present embodiment, for the sake of convenience in description, two surfaces that are opposite to each other in the length direction (L-axis direction) are defined as a first surface S1 and a second surface S2, two surfaces that are opposite to each other in the width direction (W-axis direction) and connect the first surface S1 and the second surface S2 are defined as a third surface S3 and a fourth surface S4, and two surfaces that are opposite to each other in the thickness direction (T-axis direction) and connect the first surface S1, the second surface S2, the third surface S3, and the fourth surface S4 are defined as a fifth surface S5 and a sixth surface S6.

[0051] Therefore, the first direction along which the first surface S1 and the second surface S2 face each other can be the length direction (L-axis direction), and the second direction and the third direction that are perpendicular to the first direction and perpendicular to each other can be the thickness direction (T-axis direction) and the width direction (W-axis direction) respectively, or can be the width direction (W-axis direction) and the thickness direction (T-axis direction) respectively.

[0052] Based on an optical microscope photograph or a scanning electron microscope (SEM) photograph obtained by scanning a cross-section of the ceramic body 110 in the length direction (L-axis direction)-thickness direction (T-axis direction) taken at the center of the ceramic body 110 in the width direction (W-axis direction), the length of the ceramic body 110 can refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the length direction (L-axis direction), the maximum value among the lengths of a plurality of line segments parallel to the length direction (L-axis direction). In addition, the length of the ceramic body 110 can refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the length direction (L-axis direction), the minimum value among the lengths of a plurality of line segments parallel to the length direction (L-axis direction). On the other hand, the length of the ceramic body 110 can refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the length direction (L-axis direction), the arithmetic average of the lengths of at least two line segments among a plurality of line segments parallel to the length direction (L-axis direction).

[0053] Based on an optical microscope photograph or a scanning electron microscope (SEM) photograph obtained by scanning a cross-section of the ceramic body 110 in the length direction (L-axis direction)-thickness direction (T-axis direction) taken at the center of the ceramic body 110 in the width direction (W-axis direction), the thickness of the ceramic body 110 may refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the thickness direction (T-axis direction), the maximum value among the lengths of a plurality of line segments parallel to the thickness direction (T-axis direction). In addition, the thickness of the ceramic body 110 may refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the thickness direction (T-axis direction), the minimum value among the lengths of a plurality of line segments parallel to the thickness direction (T-axis direction). On the other hand, the thickness of the ceramic body 110 may refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the thickness direction (T-axis direction), the arithmetic mean of the lengths of at least two line segments among a plurality of line segments parallel to the thickness direction (T-axis direction).

[0054] Based on an optical microscope photograph or a scanning electron microscope (SEM) photograph obtained by scanning a cross-section of the ceramic body 110 in the length direction (L-axis direction)-width direction (W-axis direction) taken at the center of the ceramic body 110 in the thickness direction (T-axis direction), the width of the ceramic body 110 may refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the width direction (W-axis direction), the maximum value among the lengths of a plurality of line segments parallel to the width direction (W-axis direction). In addition, the width of the ceramic body 110 may refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the width direction (W-axis direction), the minimum value among the lengths of a plurality of line segments parallel to the width direction (W-axis direction). On the other hand, the width of the ceramic body 110 may refer to: when connecting two outermost boundary lines of the ceramic body 110 shown in the photograph that are opposite to each other in the width direction (W-axis direction), the arithmetic mean of the lengths of at least two line segments among a plurality of line segments parallel to the width direction (W-axis direction).

[0055] The ceramic body 110 may include a plurality of dielectric layers 140 stacked in the thickness direction (T-axis direction). The boundaries between the dielectric layers 140 may be indistinct. For example, without using a scanning electron microscope (SEM), it may be difficult to identify the boundaries between the dielectric layers 140, and the plurality of dielectric layers 140 may appear as an integrated structure.

[0056] The first internal electrode 150 and the second internal electrode 160 may be alternately stacked, and the dielectric layer 140 is interposed therebetween. This stacked structure may be disposed in the ceramic body 110, and 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 of the ceramic body 110 may be the first internal electrode 150 or the second internal electrode 160.

[0057] The first internal electrode 150 and the second internal electrode 160 have different polarities and may be electrically insulated from each other by the dielectric layer 140 disposed therebetween.

[0058] The first internal electrode 150 and the second internal electrode 160 may be arranged to be offset from each other in the length direction (L-axis direction), and the dielectric layer 140 is therebetween. One end of the first internal electrode 150 may be exposed through the first surface S1 of the ceramic body 110, and one end of the second internal electrode 160 may be 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 may 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 may be connected to the second external electrode 130.

[0059] The first internal electrode 150 and the second internal electrode 160 may be formed by printing a conductive paste including a conductive metal on the surface of the dielectric layer 140. For example, the internal electrodes may be formed by printing a conductive paste including nickel (Ni) or a nickel (Ni) alloy on the surface of the dielectric layer using screen printing or gravure printing. However, this embodiment is not limited thereto.

[0060] For example, the average thickness of the first internal electrode 150 and the second internal electrode 160 may be about greater than or equal to 0.1 μm and less than or equal to 2 μm.

[0061] Here, the thickness of the internal electrode may refer to the average thickness of one internal electrode disposed between two dielectric layers. Based on a photograph obtained by scanning a cross-section of the ceramic body 110 in the length direction (L-axis direction)-thickness direction (T-axis direction) taken at the center in the width direction (W-axis direction) of the ceramic body 110 using a scanning electron microscope (SEM) at a magnification of 10,000, the average thickness of the internal electrode may be: in the photograph of the above cross-section, the arithmetic mean of the thicknesses (dimensions in the T-axis direction) of one internal electrode measured at 30 equally spaced points in the length direction (L-axis direction). The aforementioned 30 points may be specified in the effective region described below. The average thickness of the internal electrode may be further summarized in this way by measuring the average thickness of each of the ten internal electrodes and then obtaining the arithmetic mean of the measured values.

[0062] When a voltage is applied to the first outer electrode 120 and the second outer electrode 130, charges accumulate between the first inner electrode 150 and the second inner electrode 160 facing each other. That is, a capacitance can be obtained between the first inner electrode 150 electrically connected to the first outer electrode 120 and the second inner electrode 160 electrically connected to the second outer electrode 130. The capacitance of the multilayer ceramic capacitor 1000 is proportional to the overlapping area of the first inner electrode 150 and the second inner electrode 160 that overlap each other in the thickness direction (T-axis direction).

[0063] In other words, the multilayer ceramic capacitor may include an effective region and an edge region. The effective region may refer to a region where the first inner electrode 150 and the second inner electrode 160 overlap in the thickness direction (T-axis direction), and the edge region may refer to the regions between the effective region and the first surface S1 of the ceramic body 110 and between the effective region and the second surface S2 of the ceramic body 110.

[0064] The first covering layer 143 and the second covering layer 145 may be provided outside the effective region in the thickness direction (T-axis direction).

[0065] The first covering layer 143 is provided between the fifth surface S5 of the ceramic body 110 and the inner electrode closest to the fifth surface S5. The second covering layer 145 is provided between the sixth surface S6 of the ceramic body 110 and the inner electrode closest to the sixth surface S6.

[0066] That is, the first covering layer 143 may be provided on the uppermost inner electrode within the ceramic body 110, and the second covering layer 145 is provided below the lowermost inner electrode within the ceramic body 110. The first covering layer 143 and the second covering layer 145 may have the same composition as that of the dielectric layer 140. The first covering layer 143 may be formed by stacking one or more dielectric layers on the outer surface of the uppermost inner electrode, and the second covering layer 145 may be formed by stacking one or more dielectric layers on the outer surface of the lowermost inner electrode.

[0067] The first covering layer 143 and the second covering layer 145 can be used to prevent damage to the first inner electrode 150 and the second inner electrode 160 caused by physical stress and / or chemical stress.

[0068] The dielectric layer 140 may include a ceramic material having a high dielectric constant. For example, the ceramic material may include a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. In addition, these components may further include sub-components such as manganese (Mn) compounds, iron (Fe) compounds, chromium (Cr) compounds, cobalt (Co) compounds, and nickel (Ni) compounds. For example, the dielectric layer may include (Ba 1-x Cax )TiO3 (0 < x < 1), Ba(Ti 1-y Ca y )O3 (0 < y < 1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (0 < x < 1, 0 < y < 1) or Ba(Ti 1-y Zr y )O3 (0 < y < 1), but not limited thereto.

[0069] In addition, the dielectric layer 140 may further include one or more of a ceramic additive, an organic solvent, a plasticizer, an adhesive, and a dispersant. The ceramic additive may be, for example, a transition metal oxide or a transition metal carbide, a rare earth element, magnesium (Mg), or aluminum (Al).

[0070] For example, the average thickness of the dielectric layer 140 may be from 0.1 m to 10 m, but not limited thereto.

[0071] The first external electrode 120 and the second external electrode 130 are disposed outside the ceramic body 110.

[0072] The first external electrode 120 may be disposed on the first surface S1 of the ceramic body 110 and extend to at least one of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110. For example, it extends to a part of each of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110. The second external electrode 130 may be disposed on the second surface S2 of the ceramic body 110 and extend to at least one of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110. For example, it extends to a part of each of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110.

[0073] The first external electrode 120 includes a first electrode layer 121 and a first conductive resin layer 123.

[0074] The first electrode layer 121 includes a conductive metal. The first electrode layer 121 may include, for example, one or more of silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and their alloys.

[0075] The first electrode layer 121 includes a first end portion 125 and a first side portion 127.

[0076] The first end portion 125 covers the first surface S1 of the ceramic body 110 and is electrically connected to the exposed ends of the plurality of first internal electrodes 150.

[0077] The first side portion 127 extends from the first end portion 125 to cover a part of the third surface S3, a part of the fourth surface S4, a part of the fifth surface S5, and a part of the sixth surface S6 of the ceramic body 110.

[0078] The first electrode layer 121 may be a fired electrode including a conductive metal and glass. The first electrode layer 121 can be formed by dipping the first surface S1 of the ceramic body 110 in a slurry including a conductive metal and glass and then firing it. Optionally, the first electrode layer 121 can be formed by transferring a sheet including a conductive metal and glass onto the ceramic body 110. Accordingly, both the first end portion 125 and the first side portion 127 of the first electrode layer 121 may include glass and a conductive metal.

[0079] The first conductive resin layer 123 covers the first side portion 127 and covers a part of the third surface S3, a part of the fourth surface S4, a part of the fifth surface S5, and a part of the sixth surface S6 of the ceramic body 110.

[0080] For example, the first conductive resin layer 123 may completely cover the first side portion 127.

[0081] In addition, the length of the first conductive resin layer 123 may be greater than the length of the first side portion 127. Here, the length of the first conductive resin layer 123 and the length of the first side portion 127 are measured based on an optical microscope photograph or a scanning electron microscope (SEM) photograph obtained by scanning a cross-section in the length direction (L-axis direction)-thickness direction (T-axis direction) of the multilayer ceramic capacitor 1000 taken at the center in the width direction (W-axis direction) of the ceramic body 110. The length of the first conductive resin layer 123 may refer to: when connecting two outermost boundary lines opposite to each other in the length direction (L-axis direction) of the first conductive resin layer 123 shown in the photograph, the maximum value among the lengths of a plurality of line segments parallel to the length direction (L-axis direction). In addition, the length of the first side portion 127 may refer to: when connecting two outermost boundary lines opposite to each other in the length direction (L-axis direction) of the first side portion 127 shown in the photograph, the maximum value among the lengths of a plurality of line segments parallel to the length direction (L-axis direction). Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used.

[0082] The first conductive resin layer 123 may include a first conductive connection portion 123a containing an intermetallic compound and a resin 123b.

[0083] The resin 123b included in the first conductive resin layer 123 may be, for example, various known thermosetting resins such as epoxy resin, phenolic resin, urethane resin, silicone resin, and polyimide resin.

[0084] In addition, the first conductive resin layer 123 may include a conductive metal as a filler. For example, the filler may include copper (Cu), silver (Ag), nickel (Ni), tin (Sn), or an alloy thereof.

[0085] An intermetallic compound refers to any one of the compounds composed of a certain proportion of two or more elemental metals. The intermetallic compound can be formed by reacting at least one of copper (Cu), silver (Ag), copper (Cu) coated with silver (Ag), copper (Cu) coated with tin (Sn), and nickel (Ni) as high melting point metals included in the conductive resin composition for forming the first conductive resin layer 123 with tin (Sn), a tin (Sn) alloy, bismuth (Bi), or a bismuth (Bi) alloy as low melting point metals. The intermetallic compound formed in this way may include at least one of Cu6Sn5, Cu3Sn, Ni3Sn, and Ag3Sn. The intermetallic compound can be identified using energy dispersive X-ray spectroscopy (EDAX) elemental analysis. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art can also be used.

[0086] Bismuth (Bi) does not directly form an intermetallic compound, but can be used to lower the melting point of tin (Sn) during the intermetallic compound formation process. In other words, as the content of bismuth (Bi) increases, the melting point of tin (Sn) can be lowered. In addition, the low melting point metal and the remaining intermetallic compound after the formation of the intermetallic compound can be included in the first conductive connection portion 123a. That is, the first conductive connection portion 123a may include 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 may have a melting point less than or equal to 300 °C, and more specifically, may have a melting point of 200 °C to 250 °C.

[0087] In addition, based on the total weight of the metals in the first conductive connection portion 123a, the first conductive connection portion 123a may include 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%. For example, the remaining metal after the formation of the intermetallic compound may be copper (Cu).

[0088] If the tin (Sn) content is less than 36 wt% and the bismuth (Bi) content is less than 14 wt% or if the tin (Sn) content is greater than 50.4 wt% and the bismuth (Bi) content is greater than 19.6 wt%, the intermetallic compound may not be formed sufficiently or the connectivity of the intermetallic compound may be reduced, and the plating may not be formed sufficiently. For example, plating breakage may occur.

[0089] Here, the contents of tin (Sn) and bismuth (Bi) can be examined by energy dispersive X-ray spectroscopy (EDAX) elemental analysis. Other methods and / or tools understood by those of ordinary skill in the art can also be used even if not described in the present disclosure.

[0090] After the first electrode layer 121 is formed, a conductive resin composition including metal powder and a thermosetting resin can be coated on the first electrode layer 121. Here, the thermosetting resin can be a bisphenol A resin, ethylene glycol epoxy resin, phenolic epoxy resin, or a resin having a low molecular weight among their derivatives and being liquid at room temperature, but is not limited thereto. For example, the conductive resin composition can be prepared by the following method: mixing silver (Ag) powder, copper (Cu) powder, silver (Ag)-coated copper (Cu) powder, tin (Sn)-based solder powder, and a thermosetting resin and then dispersing the mixture using a 3-roll mill. The tin (Sn)-based solder powder can include at least 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. Thereafter, the conductive resin composition on the first end portion 125 can be removed, and then the first conductive resin layer 123 can be formed on the first side portion 127 by curing. Accordingly, the first end portion 125 can be disposed on the first surface S1 of the ceramic body 110, and the first side portion 127 and the first conductive resin layer 123 can be disposed on the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6.

[0091] Different from this embodiment, if both the electrode layer and the resin layer covering the electrode layer are disposed on the first surface S1 of the ceramic body 110, the resin layer has lower electrical connectivity than the electrode layer, so the equivalent series resistance (ESR) of the first external electrode 120 can be increased. There is also a risk of warping due to the exhaust from the resin layer during the high-temperature reflow process. In addition, compared with the case where the resin layer of this embodiment is not formed on the first surface S1 of the ceramic body 110, since the resin layer is disposed on the electrode layer, the external electrode may be thicker and the relative volume of the ceramic body 110 may be smaller, resulting in a reduction in the effective capacitance of the multilayer ceramic capacitor.

[0092] On the other hand, according to this embodiment, the first end portion 125 is disposed on the first surface S1 of the ceramic body 110 and the first side 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 of the ceramic body 110. Therefore, the foregoing problems may not occur.

[0093] The second external electrode 130 includes a second electrode layer 131 and a second conductive resin layer 133.

[0094] The second electrode layer 131 includes a conductive metal. The second electrode layer 131 may include, for example, one or more of silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and their alloys.

[0095] The second electrode layer 131 includes a second end portion 135 and a second side portion 137.

[0096] The second end portion 135 covers the second surface S2 of the ceramic body 110 and is electrically connected to the exposed ends of the plurality of second internal electrodes 160.

[0097] The second side portion 137 extends from the second end portion 135 to cover a part of the third surface S3, a part of the fourth surface S4, a part of the fifth surface S5, and a part of the sixth surface S6 of the ceramic body 110.

[0098] The second conductive resin layer 133 covers the second side portion 137 and covers a part of the third surface S3, a part of the fourth surface S4, a part of the fifth surface S5, and a part of the sixth surface S6 of the ceramic body 110.

[0099] Since the structure, material, and function of the second external electrode 130 correspond to those of the first external electrode 120 except for its position being different from that of the first external electrode 120, redundant descriptions thereof are omitted.

[0100] In addition, the multilayer ceramic capacitor 1000 may further include a first plating layer 180 and a second plating layer 190.

[0101] The first plating layer 180 covers the first external electrode 120. The first plating layer 180 may include a first layer 181 and a second layer 183. The first layer 181 may be disposed on the first external electrode 120 and the second layer 183 may be disposed on the first layer 181. The first layer 181 may include nickel (Ni) and the second layer 183 may include tin (Sn), but this embodiment is not limited thereto.

[0102] The second plating layer 190 covers the second external electrode 130. The second plating layer 190 may include a third layer 191 and a fourth layer 193. The third layer 191 may be disposed on the second external electrode 130 and the fourth layer 193 may be disposed on the third layer 191. The third layer 191 may include nickel (Ni) and the fourth layer 193 may include tin (Sn), but this embodiment is not limited thereto.

[0103] In addition, Figure 5 is a diagram schematically showing region A according to another embodiment.

[0104] Reference Figure 5 , in addition to the first conductive connection portion 123a and the resin 123b, the first conductive resin layer 123 may further include a plurality of metal particles 123c. The plurality of metal particles 123c may 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 remaining after the formation of an intermetallic compound, and the intermetallic compound is formed by reacting with a low-melting-point metal having a melting point lower than the curing temperature of the resin 123b in the process of curing the first conductive resin layer 123. The metal powder included in the conductive resin composition for forming the first conductive resin layer 123 may mainly react with the tin (Sn)-based solder powder to form the first conductive connection portion 123a, thereby preventing warping between the first side portion 127 and the first conductive resin layer 123.

[0105] In addition, Figure 6 is a diagram schematically showing region A according to another embodiment.

[0106] Reference Figure 6 , the first interface layer 129 may be provided between the first side portion 127 and the first conductive resin layer 123. The first interface layer 129 may include an intermetallic compound. The intermetallic compound included in the first interface layer 129 may include Cu3Sn. The first interface layer 129 may be formed by the following method: in the process of forming the first conductive resin layer 123 by coating, drying, and curing the conductive resin composition, copper (Cu) included in the first electrode layer 121 reacts with tin (Sn) or a tin (Sn) alloy included in the first conductive resin layer 123, but the present disclosure is not limited thereto.

[0107] The first interface layer 129 may connect the first side portion 127 and the first conductive connection portion 123a of the first conductive resin layer 123. The first interface layer 129 may ensure excellent mechanical properties and electrical connectivity between the first side portion 127 and the first conductive resin layer 123. For example, the first interface layer 129 may be formed in the form of a plurality of islands, and the plurality of islands may form a layer.

[0108] Figure 7 is a cross-sectional view schematically showing a multilayer ceramic capacitor according to another embodiment.

[0109] Reference Figure 7, the multilayer ceramic capacitor 2000 may include a third conductive resin layer 124 and a fourth conductive resin layer 134. The third conductive resin layer 124 may be discontinuously disposed between a first end portion 125 of the first electrode layer 121 and the first plating layer 180, and the fourth conductive resin layer 134 may be discontinuously disposed between a second end 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 may be arranged in the form of a plurality of islands.

[0110] As described for the multilayer ceramic capacitor shown in Figure 1 After removing the conductive resin composition coated on the first end portion 125 and the second end portion 135, a first conductive resin layer 123 located on the first side portion 127 and a second conductive resin layer 133 located on the second side portion 137 are formed by curing. If the conductive resin composition on the first end portion 125 and the second end portion 135 is not completely removed, the conductive resin composition may be cured to form a third conductive resin layer 124 and a fourth conductive resin layer 134.

[0111] According to an embodiment, the first plating layer 180 may contact the first end portion 125, and the second plating layer 190 may contact the second end portion 135. Since the third conductive resin layer 124 is discontinuously disposed, the first end portion 125 of the first electrode layer 121 and the first layer 181 of the first plating layer 180 may also be discontinuously in contact. Since the fourth conductive resin layer 134 is discontinuously disposed, the second end portion 135 of the second electrode layer 131 and the third layer 191 of the second plating layer 190 may also be discontinuously in contact.

[0112] In addition to the above, the remaining components are the same as those of the multilayer ceramic capacitor shown in Figure 1 so redundant descriptions thereof are omitted.

[0113] Hereinafter, specific examples of the present disclosure are presented. However, the examples described below are only for illustrating or explaining the present disclosure in detail and should not limit the scope of the present disclosure.

[0114] [Preparation Example 1: Manufacture of Multilayer Ceramic Capacitor] A paste including barium titanate (BaTiO3) powder is coated on a carrier film and dried to manufacture a plurality of dielectric green sheets.

[0115] A conductive paste including nickel (Ni) is coated on the dielectric green sheet using a screen printing method to form a conductive paste layer.

[0116] A plurality of dielectric green sheets are stacked such that at least a part of the conductive paste layers are stacked on each other to manufacture a dielectric green sheet stack.

[0117] After cutting the dielectric green sheet stack into individual sheets, debinding is performed by holding the individual sheets at a temperature of 350 °C for 66 hours in an air atmosphere, and firing is performed at a temperature of 1165 °C to fabricate a ceramic body.

[0118] A paste including a frit and copper (Cu) is coated onto the outer surface of the ceramic body by impregnation, dried, and then fired to form an electrode layer.

[0119] The ceramic body is impregnated in a conductive resin composition including an epoxy resin, tin (Sn), bismuth (Bi), and copper (Cu). Here, as shown in Table 1, the contents of tin (Sn), bismuth (Bi), and copper (Cu) in the conductive resin layer of the outer electrode in the examples and comparative examples are adjusted.

[0120] The conductive resin composition is removed from the first surface and the second surface of the ceramic body using a porous nonwoven fabric, and then cured to form a conductive resin layer.

[0121] Thereafter, nickel (Ni) plating and tin (Sn) plating are performed, and heat treatment is performed at a temperature of 160 °C for 1 hour to fabricate a multilayer ceramic capacitor.

[0122] (Table 1) (Unit: wt%) (Experimental Example 1) The plating breakage is determined as follows. After chemically peeling the tin (Sn) plating from the Ni / Sn plating of the multilayer ceramic capacitor, an SEM image of the exterior of the multilayer ceramic capacitor is observed such that the nickel (Ni) plating on both sides of the multilayer ceramic capacitor in the longitudinal direction (L-axis direction) and the surface of the ceramic body between the Ni plating are simultaneously visible. In the above SEM image, the coverage of the Ni plating at the edges of the multilayer ceramic capacitor that are opposite to each other in the direction perpendicular to the longitudinal direction (L-axis direction) is observed. In each of the four edges, "plating breakage" occurring at the edge where the outer electrode or the ceramic body is exposed due to insufficient formation of the Ni plating is determined. In particular, if the length of the portion where plating breakage occurs is greater than or equal to 25% of the length of the edge, it is considered defective.

[0123] The defect incidence rate due to plating breakage of the outer electrodes of the multilayer ceramic capacitors fabricated in the examples and comparative examples is examined, and the results are shown in Table 2.

[0124] (Table 2) (Unit: %) Referring to Table 2, in the multilayer ceramic capacitors according to Examples 1 to 3, no plating fracture occurred, but in the multilayer ceramic capacitors according to Comparative Examples 1 to 6, the defect incidence rate of plating fracture was 5% to 31%. That is, 31 out of 100 samples according to Comparative Example 1, 21 out of 100 samples according to Comparative Example 2, 14 out of 100 samples according to Comparative Example 3, 8 out of 100 samples according to Comparative Example 4, 5 out of 100 samples according to Comparative Example 5, and 7 out of 100 samples according to Comparative Example 6 each exhibited plating fracture. This is because more intermetallic compounds were formed in the examples and the intermetallic compounds have excellent connectivity compared to the comparative examples.

[0125] [Preparation Example 2: Manufacture of Multilayer Ceramic Capacitor] (Example 4) Manufacture a multilayer ceramic capacitor according to Preparation Example 1, but the contents of tin (Sn), bismuth (Bi), and copper (Cu) are the same as those of tin (Sn), bismuth (Bi), and copper (Cu) in Example 1.

[0126] (Comparative Example 7) Apply a paste containing barium titanate (BaTiO3) powder onto a carrier film and dry it to manufacture a plurality of dielectric green sheets.

[0127] Apply a conductive paste containing nickel (Ni) onto the dielectric green sheet using a screen printing method to form a conductive paste layer.

[0128] Stack a plurality of dielectric green sheets such that at least a part of the conductive paste layers overlap each other to manufacture a dielectric green sheet stack.

[0129] After cutting the dielectric green sheet stack into individual sheets, perform debinding by holding the individual sheets at a temperature of 350 °C for 66 hours in an air atmosphere, and perform firing at a temperature of 1165 °C to manufacture a ceramic body.

[0130] Apply a paste containing frit and copper (Cu) onto the outer surface of the ceramic body by dipping, dry it, and then fire it to form an electrode layer.

[0131] Immerse the ceramic body in a conductive resin composition containing epoxy resin, tin (Sn), bismuth (Bi), and copper (Cu). Here, adjust the contents of tin (Sn), bismuth (Bi), and copper (Cu) to be the same as those in Example 4.

[0132] Post-cure the conductive resin composition to form a conductive resin layer.

[0133] Thereafter, perform nickel (Ni) plating and tin (Sn) plating to manufacture a multilayer ceramic capacitor.

[0134] [Experimental Example: Performance of Multilayer Ceramic Capacitors] (Experimental Example 2) Measure the moisture resistance of the multilayer ceramic capacitors fabricated in Example 4 and Comparative Example 7.

[0135] Using a stencil mask on a printed circuit board (PCB) dedicated to the moisture resistance characteristics of 40 channels, the solder paste is patterned. Thereafter, a reflow process is performed at a maximum temperature of 260°C and the prepared samples are mounted on the PCB. The prepared PCB is mounted in a cell where the potential difference and current can be measured and placed in a chamber with a temperature of 85°C and a humidity of 60%RH. Thereafter, in the first step of applying a potential difference of 7.56V across the sample ends for 1 hour and the second step for 1 hour, and in the third step of applying a potential difference of 4.5V across the sample ends for 2 hours, the degree of deterioration of the insulation resistance (IR) is examined to measure the moisture resistance, and the results are shown in Table 3.

[0136] (Table 3) Referring to Table 3, the insulation resistance of the multilayer ceramic capacitor fabricated in Comparative Example 7 drops to 10 7 Ω in the third step, while the insulation resistance of the multilayer ceramic capacitor fabricated in Example 4 remains at 10 9 Ω, showing excellent moisture resistance.

[0137] (Experimental Example 3) In Figure 8 are shown the results of measuring the equivalent series resistance of the multilayer ceramic capacitors fabricated in Example 4 and Comparative Example 7.

[0138] Referring to Figure 8 , the average equivalent series resistance (ESR) of the multilayer ceramic capacitor fabricated according to Example 4 is 1.55 mΩ, and the average equivalent series resistance (ESR) of the multilayer ceramic capacitor fabricated according to Comparative Example 7 is 3.26 mΩ. That is, the equivalent series resistance of Example 4 is smaller than that of Comparative Example 7. This is because the electrical connectivity is improved by directly forming a plating layer on the electrode layers on the first and second surfaces of the ceramic body without providing a resin layer.

[0139] (Experimental Example 4) Using Figure 9 the bending test method shown in

[0140] Referring to Figure 9, a multilayer ceramic capacitor is mounted on a substrate, and the surface of the substrate opposite to the mounting surface of the multilayer ceramic capacitor is pressed by 3 mm (i.e., the maximum movement of the force application point is 3 mm) to determine whether bending cracks occur and to measure the frequency of crack occurrence.

[0141] In the bending strength test, among 30 samples of each of Example 4 and Comparative Example 7, no cracks that damaged the ceramic body occurred in Example 4 and Comparative Example 7.

[0142] In this way, the multilayer ceramic capacitor according to Example 4 showed the same bending strength as that of Comparative Example 7.

[0143] (Experimental Example 5) Figure 10A is an X-ray photograph for confirming whether warping occurs in the multilayer ceramic capacitor according to Example 4 after reflow, and Figure 10B is an X-ray photograph for confirming whether warping occurs in the multilayer ceramic capacitor according to Comparative Example 7 after reflow.

[0144] In Example 4 and Comparative Example 7, among 40 samples of each of Example 4 and Comparative Example 7, no warping occurred after reflow. In this way, the multilayer ceramic capacitor according to Example 4 showed the same level as that of Comparative Example 7.

[0145] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and various modifications can be made within the scope covered by the claims, the description of the present disclosure, and the drawings, and such modifications also fall within the scope of the present disclosure.

Claims

1. A multilayer ceramic capacitor comprising: a ceramic body having a first surface and a second surface opposite to each other in a first direction, a third surface and a fourth surface opposite to each other in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface opposite to each other in a third direction and connecting the first surface, the second surface, the third surface and the fourth surface, and comprising a plurality of first internal electrodes and a plurality of second internal electrodes disposed inside the ceramic body; and The first external electrode and the second external electrode are arranged outside the ceramic body, Wherein, the first external electrode comprises a first electrode layer and a first conductive resin layer, and the first electrode layer comprises: a first end portion disposed on the first surface and electrically connected to the plurality of first internal electrodes; and a first side portion extending from the first end portion to at least one of the third surface, the fourth surface, the fifth surface, and the sixth surface, and The first conductive resin layer covers at least a portion of the first side portion, Wherein, the second external electrode comprises a second electrode layer and a second conductive resin layer, and the second electrode layer comprises: a second end portion disposed on the second surface and electrically connected to the plurality of second internal electrodes; and a second side portion extending from the second end portion to at least one of the third surface, the fourth surface, the fifth surface, and the sixth surface, and The second conductive resin layer covers at least a portion of the second side portion, and Wherein, the first conductive resin layer and the second conductive resin layer include Sn and Bi.

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

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

4. The multilayer ceramic capacitor of claim 1, wherein: The first conductive resin layer includes a resin and a first conductive connection portion including an intermetallic compound, and The second conductive resin layer includes the resin and a second conductive connecting portion including the intermetallic compound.

5. The multilayer ceramic capacitor of claim 4, wherein: The first conductive connection portion includes: Sn in an amount of 36 wt % or more and 50.4 wt % or less; and Bi in an amount of 14 wt % or more and 19.6 wt % or less, and The second conductive connection portion includes: Sn in an amount of 36 wt % or more and 50.4 wt % or less; and Bi in an amount of 14 wt % or more and 19.6 wt % or less.

6. The multilayer ceramic capacitor of claim 4, wherein: The intermetallic compound included in the first conductive resin layer and the intermetallic compound included in the second conductive resin layer include at least one of Cu6Sn5, Cu3Sn, Ni3Sn, and Ag3Sn.

7. The multilayer ceramic capacitor of claim 1, wherein: 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, and The second external electrode further includes a second interface layer including the intermetallic compound and disposed between the second conductive resin layer and the second side portion.

8. The multilayer ceramic capacitor of claim 7, wherein: The intermetallic compound included in the first interface layer and the intermetallic compound included in the second interface layer include Cu 3 Sn.

9. The multilayer ceramic capacitor of claim 1, further comprising: A first plating layer and a second plating layer, wherein the first plating layer covers the first external electrode, and the second plating layer covers the second external electrode.

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

11. The multilayer ceramic capacitor of claim 10, wherein: The first layer and the third layer include Ni, and The second layer and the fourth layer include Sn.

12. The multilayer ceramic capacitor of claim 9, further comprising: a third conductive resin layer disposed discontinuously between the first end portion and the first plating layer; as well as The fourth conductive resin layer is discontinuously provided between the second end portion and the second plating layer.

13. The multilayer ceramic capacitor of claim 9, wherein: The first plating layer contacts the first end portion, and The second plating layer contacts the second end portion.

14. The multilayer ceramic capacitor of claim 13, wherein: The first conductive resin layer includes a resin and a first conductive connection portion including an intermetallic compound, and The second conductive resin layer includes the resin and a second conductive connecting portion including the intermetallic compound.

15. The multilayer ceramic capacitor of claim 14, wherein: The first conductive connection portion includes: Sn in an amount of 36 wt % or more and 50.4 wt % or less, and Bi in an amount of 14 wt % or more and 19.6 wt % or less.

16. The multilayer ceramic capacitor according to claim 15, wherein: The resin includes epoxy resin.

17. The multilayer ceramic capacitor according to claim 16, wherein: The first end portion includes glass and a conductive metal.

Images