Multilayer capacitor

Abstract

To provide a multilayer capacitor which includes an external electrode and enables efficient improvement of the performance thereof (reliability, durability, lamination stability, and reduction of an equivalent series resistance value).SOLUTION: A multilayer capacitor includes: a main body including laminated structure in which at least one first internal electrode 121 and at least one second internal electrode are alternately laminated in a first direction with at least one dielectric layer 111 interposed therebetween; and a first and a second external electrodes arranged on the main body while being spaced apart from each other so that each of the first and the second external electrodes are connected to at least one first internal electrode and at least one second internal electrode. Each of the first and second external electrodes includes a conductive resin layer 131b including: resin 139; a plurality of metal particles 137a, 137c; and a conductive connecting portion 138a connecting a part of the plurality of metal particles to each other. In the conductive resin layer, among the plurality of metal particles relative to a sum of the plurality of metal particles and the conductive connecting portion, a volume ratio of the metal particles separated from the conductive connecting portion is more than 0% and less than 4.9%.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Multilayer capacitors are widely used as components in electronic devices such as computers, PDAs, and mobile phones due to their advantages of being compact, ensuring high capacitance, and being easy to mount. They have high reliability and high strength properties, and are also widely used as components for electrical equipment (including vehicles).

[0003] A multilayer capacitor may include an external electrode for providing capacitance to the outside. The external electrode is sometimes required to have reliability for being stably mounted or embedded in a substrate or electronic device, reliability for preventing moisture and / or plating solution from penetrating into the multilayer capacitor, durability for withstanding external impact and temperature changes well, lamination stability with respect to the internal structure and external structure of the external electrode, and a low equivalent series resistance (ESR). [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Korean Patent Publication No. 10-2021-0043543 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] The present invention provides a multilayer capacitor that can efficiently improve the performance of an external electrode (for example, at least one of reliability, durability, lamination stability, and reduction of equivalent series resistance). [Means for Solving the Problem]

[0006] A stacked capacitor according to one embodiment of the present invention includes a body having a stacked structure in which at least one first internal electrode and at least one second internal electrode are alternately stacked in a first direction with at least one dielectric layer in between, and first and second external electrodes disposed on the body spaced apart from each other so as to be connected to the at least one first internal electrode and at least one second internal electrode, respectively, wherein each of the first and second external electrodes includes a conductive resin layer comprising a resin, a plurality of metal particles, and conductive connecting portions that connect a portion of the plurality of metal particles to each other, and in the conductive resin layer, the volume ratio of metal particles separated from the conductive connecting portions to the sum of the plurality of metal particles and the conductive connecting portions may be greater than 0% and less than 4.9%. [Effects of the Invention]

[0007] A multilayer capacitor according to one embodiment of the present invention can efficiently improve the performance of the external electrodes (e.g., at least one of reliability, durability, stacking stability, and reduction of equivalent series resistance). [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing a multilayer capacitor according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view along the line A-A' in Figure 1. [Figure 3a] This is a cross-sectional view along the line B-B' in Figure 1. [Figure 3b] This is a cross-sectional view showing the external electrodes of a multilayer capacitor according to one embodiment of the present invention. [Figure 4] This is an enlarged cross-sectional view of C in Figure 3b. [Figure 5] This graph shows the likelihood of delamination failure (Delamination NG) within the external electrode, based on the volume ratio (Out Rate) of metal particles separated from the conductive connector relative to the sum of multiple metal particles and the conductive connector. [Figure 6a]This is a photograph showing a cross-section of the external electrode based on the volume ratio (Out Rate) of metal particles separated from the conductive connection point. [Figure 6b] This is a photograph showing a cross-section of the external electrode based on the volume ratio (Out Rate) of metal particles separated from the conductive connection point. [Figure 6c] This is a photograph showing a cross-section of the external electrode based on the volume ratio (Out Rate) of metal particles separated from the conductive connection point. [Figure 7a] This is a photograph showing a cross-section of a multilayer capacitor based on the volume ratio (Out Rate) of metal particles separated from the conductive junction. [Figure 7b] This is a photograph showing a cross-section of a multilayer capacitor based on the volume ratio (Out Rate) of metal particles separated from the conductive junction. [Figure 8a] This is an X-ray image showing the side view of a multilayer capacitor based on the volume ratio (Out Rate) of metal particles separated from the conductive coupling portion. [Figure 8b] This is an X-ray image showing the side view of a multilayer capacitor based on the volume ratio (Out Rate) of metal particles separated from the conductive coupling portion. [Figure 9a] This is a cross-sectional view showing the external electrodes of a multilayer capacitor according to one embodiment of the present invention, before the conductive coupling portion is formed. [Figure 9b] This is a cross-sectional view showing the external electrodes after the conductive connecting portion has been formed in a multilayer capacitor according to one embodiment of the present invention. [Figure 10a] This photograph shows a cross-section of an external electrode, illustrating the ratio of metal particles containing a shell (coating) to multiple metal particles (core-shell ratio). [Figure 10b] This photograph shows a cross-section of an external electrode, illustrating the ratio of metal particles containing a shell (coating) to multiple metal particles (core-shell ratio). [Figure 11] This graph shows the amount of gas, such as carbon dioxide (CO2), generated at the external electrode as temperature changes. [Modes for carrying out the invention]

[0009] Embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, embodiments of the present invention are provided to more completely explain the present invention to those having average knowledge in the relevant technical field. Therefore, the shapes and dimensions of elements in the drawings may be exaggerated for clearer explanation, and elements indicated by the same reference numerals in the drawings are the same elements.

[0010] In the drawings, portions unrelated to the description are omitted to clearly explain the present invention, thicknesses are enlarged to clearly express a plurality of layers and regions, and the same reference numerals are used to describe components having the same function within the scope of the same concept. Throughout the specification, when a certain portion "comprises" a certain component, this means that unless specifically stated to the contrary, it does not exclude other components, but may further include other components.

[0011] To clearly explain embodiments of the present invention, when the directions of a hexahedron are defined, X, Y, and Z shown in the drawings respectively indicate the length direction, the width direction, and the thickness direction. Here, the thickness direction may be used as the same concept as the lamination direction (or first direction) in which dielectric layers are laminated.

[0012] Hereinafter, a multilayer capacitor according to an embodiment of the present invention will be described, and is particularly described as a multi-layer ceramic capacitor (MLCC), but the present invention is not limited thereto.

[0013] FIG. 1 is a perspective view showing a multilayer capacitor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line A-A' of FIG. 1, and FIG. 3a is a cross-sectional view taken along line B-B' of FIG. 1. Although FIG. 1 shows a form cut by about 1 / 4 of the volume to show the inside of a main body 110, an actual multilayer capacitor 100 does not have to be cut by about 1 / 4 of the volume, and may have a substantially symmetrical form with reference to each of the X direction, Y direction and Z direction from the center.

[0014] Referring to FIGS. 1, 2 and 3a, a multilayer capacitor 100 according to an embodiment of the present invention may include a main body 110, a first external electrode 131, and a second external electrode 132.

[0015] The main body 110 may include a stacked structure in which at least one first internal electrode 121 and at least one second internal electrode 122 are alternately stacked in a first direction (e.g., Z direction) with at least one dielectric layer 111 interposed therebetween.

[0016] For example, the main body 110 may be configured as a ceramic main body by firing the stacked structure. Here, the at least one dielectric layer 111 disposed in the main body 110 is in a sintered state, and boundaries between adjacent dielectric layers can be integrated to such an extent that they are difficult to confirm without using a Scanning Electron Microscope (SEM).

[0017] For example, the main body 110 may be formed as a hexahedron having both side surfaces in the length direction X, both side surfaces in the width direction Y, and both side surfaces in the thickness direction Z, and edges and / or corners of the hexahedron may be polished to have a rounded shape. However, the shape and dimensions of the main body 110 and the number of stacked dielectric layers 111 are not limited to those shown in the present embodiment.

[0018] At least one dielectric layer 111 can have its thickness arbitrarily changed to match the capacitance design of the multilayer capacitor 100, and may contain ceramic powder with a high dielectric constant, such as barium titanate (BaTiO3) based powder, but the present invention is not limited thereto. In addition, various ceramic additives (e.g., MgO, Al2O3, SiO2, ZnO), organic solvents, plasticizers, binders, dispersants, etc., can be added to the ceramic powder according to the requirements of the multilayer capacitor 100.

[0019] The average particle size of the ceramic powder used to form at least one dielectric layer 111 is not particularly limited and can be adjusted according to the requirements of the multilayer capacitor 100 (e.g., whether miniaturization and / or high capacitance are required, as in capacitors for electronic equipment, or whether high voltage withstand characteristics and / or high strength are required, as in capacitors for electrical equipment), but can be adjusted to, for example, 400 nm or less.

[0020] For example, at least one dielectric layer 111 can be formed by coating and drying a slurry containing a powder such as barium titanate (BaTiO3) onto a carrier film to provide a plurality of ceramic sheets. The ceramic sheets can be formed by mixing ceramic powder, a binder, and a solvent to produce a slurry, and then fabricating the slurry into a sheet with a thickness of several micrometers using a doctor blade method, but are not limited to this.

[0021] At least one first internal electrode 121 and at least one second internal electrode 122 can be formed by printing a conductive paste containing a conductive metal so as to be alternately exposed on one side and the other side of the body 110 in the longitudinal direction X along the stacking direction of the dielectric layer (e.g., Z direction), and can be electrically insulated from each other by a dielectric layer placed in between.

[0022] For example, each of at least one first internal electrode 121 and at least one second internal electrode 122 can be formed from a conductive paste for internal electrodes containing 40-50% by weight of conductive metal powder with an average particle size of 0.1-0.2 μm, but is not limited thereto. The conductive paste may be nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), lead (Pb), or platinum (Pt), either alone or in alloys thereof, but the present invention is not limited thereto.

[0023] For example, the conductive paste for the internal electrodes can be applied to the ceramic sheet by a printing method to form the internal electrode pattern. While screen printing, gravure printing, and inkjet printing can be used as printing methods for the conductive paste, the present invention is not limited thereto. For example, the main body 110 can be manufactured by laminating 200 to 300 layers of ceramic sheets printed with the internal electrode pattern, then pressing and firing them.

[0024] The capacitance of the multilayer capacitor 100 is proportional to the overlapping area in the stacking direction (e.g., Z direction) between at least one first internal electrode 121 and at least one second internal electrode 122, proportional to the total number of stacks of at least one first internal electrode 121 and at least one second internal electrode 122, and can be inversely proportional to the distance between at least one first internal electrode 121 and at least one second internal electrode 122. The distance between the internal electrodes may be substantially the same as the thickness of each of the at least one dielectric layer 111.

[0025] The multilayer capacitor 100 can have a larger capacitance relative to its thickness as the distance between at least one first internal electrode 121 and at least one second internal electrode 122 decreases. Conversely, the voltage withstand capability of the multilayer capacitor 100 can increase as the distance between the internal electrodes increases. Therefore, the distance between the internal electrodes can be adjusted according to the requirements of the multilayer capacitor 100 (e.g., whether miniaturization and / or high capacitance are required, as in capacitors for electronic equipment, or whether high voltage withstand capability and / or high strength are required, as in capacitors for electrical equipment). The thickness of each of the at least one first internal electrode 121 and at least one second internal electrode 122 can also be affected by the distance between the internal electrodes.

[0026] For example, when high voltage withstand characteristics and / or high strength are required, the multilayer capacitor 100 can be designed such that the distance between at least one first internal electrode 121 and at least one second internal electrode 122 exceeds twice the thickness of each electrode. For example, when miniaturization and / or high capacitance are required, the multilayer capacitor 100 can be designed such that the thickness of at least one first internal electrode 121 and at least one second internal electrode 122 is 0.4 μm or less, and the total number of layers is 400 or more.

[0027] The first and second external electrodes 131 and 132 can be arranged on the main body 110 spaced apart from each other so as to be connected to at least one first internal electrode 121 and at least one second internal electrode 122, respectively.

[0028] For example, the first and second external electrodes 131 and 132 can be formed by methods such as dipping in a paste containing a metal component, printing a conductive paste, sheet transfer, pad transfer, sputter plating, or electroplating. For example, the first and second external electrodes 131 and 132 may include a base electrode layer formed by firing the paste and a plating layer formed on the outer surface of the base electrode layer, and may further include a conductive resin layer between the base electrode layer and the plating layer. For example, the conductive resin layer may be formed by incorporating conductive particles into a thermosetting resin such as epoxy. The metal component may be copper (Cu), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), lead (Pb), tin (Sn), etc., individually or in alloys thereof, but is not limited to these.

[0029] The multilayer capacitor 100 can be mounted on or embedded in an external substrate (e.g., a printed circuit board), and can be electrically connected to a circuit (e.g., an integrated circuit, a processor) electrically connected to the external substrate by being connected to at least one of the wiring, lands, solder, and bumps of the external substrate via first and second external electrodes 131 and 132.

[0030] Referring to Figures 1, 2, and 3a, the main body 110 may include an upper cover layer 112, a lower cover layer 113, and a core region 115, and the core region 115 may include a margin region 114 and a capacity region 116.

[0031] The upper and lower cover layers 112 and 113 are arranged so as to sandwich the core region 115 in a first direction (e.g., the Z direction), and each may be thicker than each of at least one dielectric layer 111. The upper and lower cover layers 112 and 113 can prevent external environmental elements (e.g., moisture, plating solution, foreign matter) from penetrating the core region 115, protect the main body 110 from external impacts, and improve the bending strength of the main body 110.

[0032] For example, the upper and lower cover layers 112 and 113 may include the same material as at least one dielectric layer 111 or other materials (e.g., thermosetting resins such as epoxy resin).

[0033] The capacitance region 116 can include the space between at least one first internal electrode 121 and at least one second internal electrode 122, and thus can form the capacitance of the multilayer capacitor 100. The capacitance region 116 can include a multilayer structure in which at least one first internal electrode 121 and at least one second internal electrode 122 are alternately stacked in a first direction (e.g., Z direction) with at least one dielectric layer 111 in between, and can have the same size as the above multilayer structure.

[0034] The margin region 114 may include the space between the boundary line of at least one first internal electrode 121 and at least one second internal electrode 122 and the surface of the body 110. Multiple margin regions 114 may be arranged with a capacitance region 116 in between in a second direction (e.g., the Y direction) perpendicular to a first direction (e.g., the Z direction). For example, multiple margin regions 114 may be formed in a manner similar to that of at least one dielectric layer 111 (but with a different stacking direction).

[0035] The multiple margin regions 114 prevent at least one first internal electrode 121 and at least one second internal electrode 122 from being exposed on the surface of the main body 110 in a second direction (e.g., the Y direction). This prevents external environmental elements (e.g., moisture, plating solution, foreign matter) from penetrating to at least one first internal electrode 121 and at least one second internal electrode 122 through the surface in the second direction, thereby improving the reliability and lifespan of the multilayer capacitor 100. Furthermore, since at least one first internal electrode 121 and at least one second internal electrode 122 can be efficiently extended in the second direction by the multiple margin regions 114, the multiple margin regions 114 can also contribute to improving the capacitance of the multilayer capacitor 100 by increasing the overlapping area between at least one first internal electrode 121 and at least one second internal electrode 122.

[0036] Figure 3b is a cross-sectional view showing the external electrodes of a multilayer capacitor according to one embodiment of the present invention. Referring to Figure 3b, each of the first and second external electrodes 131 and 132 may include at least one of the base electrode layers 131a and 132a, conductive resin layers 131b and 132b, internal plating layers 131c and 132c, and external plating layers 131d and 132d.

[0037] The base electrode layers 131a and 132a can be placed between the conductive resin layers 131b and 132b and the main body 110, and can be connected to at least one first internal electrode 121 and at least one second internal electrode 122.

[0038] For example, the base electrode layers 131a and 132a can be formed by dipping a portion of the body 110 into a paste containing a metallic material and / or glass frit, or by firing the body 110 with the paste printed on it, and can also be formed by sheet transfer or pad transfer methods. The metallic material may be copper (Cu) to improve electrical connectivity to the body 110, but is not limited to this. For example, the metallic material may include at least one of copper (Cu), nickel (Ni), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), and lead (Pb), and may vary depending on the metallic material of the internal electrodes in the body 110.

[0039] The internal plating layers 131c and 132c can be positioned between the external plating layers 131d and 132d and the conductive resin layers 131b and 132b, and the external plating layers 131d and 132d can be positioned to cover the outer surfaces of the internal plating layers 131c and 132c.

[0040] For example, the internal plating layers 131c, 132c and the external plating layers 131d, 132d may be formed by sputtering or electroplating (electric deposition), but are not limited thereto. The external plating layers 131d, 132d may contain tin (Sn) having a melting point lower than the reflow temperature for efficiency when the first and second external electrodes 131, 132 are electrically connected and fixed to the substrate via the reflow process and solder, and the internal plating layers 131c, 132c may contain nickel (Ni) to enhance the connectivity between tin (Sn) and the metallic material (e.g., copper) of the conductive resin layers 131b, 132b, or to reduce their interaction with each other, but are not limited thereto. For example, the internal plating layers 131c and 132c may be omitted depending on the metallic material (e.g., nickel) of the conductive resin layers 131b and 132b, and may contain alternative materials such as palladium (Pd) or platinum (Pt) depending on the application of the multilayer capacitor (e.g., high voltage). For example, the internal plating layers 131c and 132c and the external plating layers 131d and 132d may be realized by copper (Cu), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), or lead (Pb), either alone or in alloys thereof.

[0041] The conductive resin layers 131b and 132b can be placed between the internal plating layers 131c and 132c and the base electrode layers 131a and 132a, and can be electrically connected to at least one first internal electrode 121 and at least one second internal electrode 122. If the base electrode layers 131a and 132a are omitted, the conductive resin layers 131b and 132b can also be directly connected to at least one first internal electrode 121 and at least one second internal electrode 122.

[0042] Because the conductive resin layers 131b and 132b contain resin, they can have relatively higher ductility compared to the base electrode layers 131a and 132a, the internal plating layers 131c and 132c, and the external plating layers 131d and 132d. Therefore, they can absorb physical shocks from the outside (including the main body) and stresses and tensile stresses that occur during the formation process of the first and second external electrodes 131 and 132 and during the mounting process on the substrate, thereby improving the durability and reliability of the first and second external electrodes 131 and 132. In addition, the conductive resin layers 131b and 132b can efficiently prevent moisture and / or plating solution from penetrating the main body 110 from the outside.

[0043] Furthermore, by ensuring that the conductive resin layers 131b and 132b are conductive, it is possible to prevent the equivalent series resistance (ESR) from becoming high. For example, the conductive resin layers 131b and 132b can be formed by dimpling or printing a resin paste, and the resin paste may further contain a metallic material to provide a seed for the conductivity and / or plating layer of the conductive resin layers 131b and 132b. The metallic material may, but is not limited to, the same as the metallic material of the base electrode layers 131a and 132a.

[0044] Figure 4 is an enlarged cross-sectional view of C in Figure 3b. Although Figure 4 shows only the first external electrode of the two external electrodes for efficient representation, the structure shown in Figure 4 can be similarly applied to the second external electrode.

[0045] Referring to Figure 4, the conductive resin layer 131b may include a resin 139, a plurality of metal particles 137a, 137c, and a conductive connecting portion 138a that connects some of the metal particles 137a to each other.

[0046] The conductive connecting portion 138a can enhance the overall electrical connectivity of multiple metal particles 137a and 137c by connecting some of the multiple metal particles 137a to each other, thereby increasing the electrical connectivity area. As a result, the conductive connecting portion 138a can have the effect of widening the electrical connectivity width of the conductive resin layer 131b, and thus further reduce the equivalent series resistance (ESR) of the conductive connecting portion 138a. For example, the conductive connecting portion 138a can form an IMC (Inter Metallic Compound) cluster by connecting some of the multiple metal particles 137a to each other.

[0047] For example, the conductive connecting portion 138a can efficiently connect some of the multiple metal particles 137a by including a metallic material (e.g., tin) that has higher fluidity than the multiple metal particles 137a and 137c in a specific temperature range (e.g., reflow process temperature). However, the metallic material of the conductive connecting portion 138a is not limited to tin, and may be at least one of low-melting-point materials such as tin (Sn), lead (Pb), indium (In), and bismuth (Bi).

[0048] Since the multiple metal particles 137a and 137c can contain metal materials (e.g., copper, silver) that have relatively higher conductivity than the conductive connecting portion 138a, they can act as a core to enhance the conductivity of the conductive resin layer 131b. Furthermore, since highly conductive metal materials may have relatively high melting points, they may be efficient in forming IMC clusters due to the difference in fluidity with the conductive connecting portion 138a. In other words, the multiple metal particles 137a and 137c can contain metal materials that have a higher melting point than the conductive connecting portion 138a and / or the outer plating layer 131d.

[0049] For example, the resin 139 may be a thermosetting resin, and the thermosetting resin may be an epoxy resin. This improves the adhesion between the conductive resin layer 131b and the base electrode layer 131a, and efficiently prevents the plating solution and moisture from penetrating the main body 110 during the formation process of the internal plating layer 131c and / or the external plating layer 131d. However, the resin 139 is not limited to epoxy resin, and may be a bisphenol A resin, glycol epoxy resin, novolac epoxy resin, or a derivative thereof, which has a small molecular weight and is liquid at room temperature.

[0050] The resin 139 can undergo high-temperature processes such as the process in which the conductive connecting portion 138a connects some of the multiple metal particles 137a to each other, the process of forming the internal plating layer 131c and / or the external plating layer 131d, and the reflow process for mounting the external electrodes. During the above high-temperature processes, the bonds between carbon (C) and oxygen (O) in the resin 139 can be oxidized as carbon dioxide (CO2) gas. Since this gas can be released from the inside to the outside of the conductive resin layer 131b, it may affect the positional stability of the conductive resin layer 131b relative to adjacent structures (e.g., main body, base electrode layer, plating layer).

[0051] Therefore, the above gas can be reduced by reducing the oxidation of the carbon (C) and oxygen (O) bonds in the resin 139. In the conductive resin layer 131b, the lower the volume ratio of the metal particles 137c separated from the conductive connecting portion 138a to the sum of the multiple metal particles 137a, 137c and the conductive connecting portion 138a, the more uniformly the conductive connecting portion 138a can be formed in the conductive resin layer 131b, and the overall interaction between the resin 139 and the separated metal particles 137c can be reduced. This can suppress the phenomenon of localized concentration of oxidation energy in the resin 139, and the gas due to oxidation of the carbon (C) and oxygen (O) bonds in the resin 139 can be reduced. Therefore, the positional stability of the conductive resin layer 131b with respect to adjacent structures (e.g., main body, base electrode layer, plating layer) can be improved, and the possibility of delamination between the conductive resin layer 131b and the adjacent structures can be reduced.

[0052] Furthermore, in the conductive resin layer 131b, the lower the volume ratio of the metal particles 137c separated from the conductive connecting portion 138a to the sum of the multiple metal particles 137a, 137c and the conductive connecting portion 138a, the more uniformly the conductive connecting portion 138a can be formed in the conductive resin layer 131b. This allows the electrical connection width of the conductive resin layer 131b to be further widened, and the equivalent series resistance (ESR) of the conductive connecting portion 138a to be further reduced.

[0053] Figure 5 is a graph showing the likelihood of delamination failure (Delamination NG) within the external electrode based on the volume ratio (Out Rate) of metal particles separated from the conductive connector relative to the sum of multiple metal particles and the conductive connector.

[0054] Referring to Figure 5, in the conductive resin layer 131b, if the volume ratio (Out Rate) of metal particles 137c separated from the conductive connecting portion 138a to the sum of multiple metal particles 137a, 137c and the conductive connecting portion 138a is 10.2%, 4.9%, 2.5%, 2%, and 0.4%, then the probability of delamination failure (Delamination NG) can be {(42 / 60)×100}%, {(31 / 60)×100}%, {(2 / 60)×100}%, {(0 / 60)×100}%, and {(0 / 60)×100}%, respectively. Here, the denominator of the above probability may be the number of measurement samples, and the numerator may be the number of samples in which delamination failure occurred. The number of samples is not limited to 60, but may be a smaller number (e.g., 20).

[0055] When the volume ratio (Out Rate) is less than 4.9%, the possibility of delamination failure (Delamination NG) can be significantly reduced. Therefore, in the conductive resin layer of a multilayer capacitor according to one embodiment of the present invention, the volume ratio (Out Rate) of metal particles separated from the conductive connecting portion among the multiple metal particles can be greater than 0% and less than 4.9%, thereby significantly reducing the possibility of delamination failure.

[0056] If the volume ratio (Out Rate) is less than 2.5%, the possibility of delamination failure (Delamination NG) may be virtually 0%. Therefore, in the conductive resin layer of a multilayer capacitor according to one embodiment of the present invention, the volume ratio (Out Rate) of metal particles separated from the conductive connecting portion among the multiple metal particles can be less than 2.5%, thereby preventing delamination failure.

[0057] Furthermore, in the conductive resin layer of a multilayer capacitor according to one embodiment of the present invention, the volume ratio (Out Rate) can be 2% or less, and peeling defects can be prevented more stably.

[0058] In the sample measured to obtain the values ​​shown in Figure 5, the mass ratio of resin to the total metal contained in the conductive resin layer may be 5% or more and 20% or less. Furthermore, in the above sample, the mass ratio of the conductive connecting portion (e.g., tin) to the sum of the metal material (e.g., silver) coated on at least a portion of the multiple metal particles in the conductive resin layer and the multiple metal particles (e.g., copper) may be 4 / 6 or more and 7 / 3 or less.

[0059] Figures 6a to 6c are photographs showing cross-sections of external electrodes based on the volume ratio (Out Rate) of metal particles separated from the conductive connection, and Figures 7a and 7b are photographs showing cross-sections of multilayer capacitors based on the volume ratio (Out Rate) of metal particles separated from the conductive connection.

[0060] Referring to Figures 6a and 7a, the volume ratio (Out Rate) of metal particles 137c separated from the conductive connecting portion 138a to the total metal particles in the conductive resin layer 131b of a multilayer capacitor according to one embodiment of the present invention is less than 4.9% (e.g., 0.4%), which can be lower than the volume ratio (Out Rate) of metal particles 137c separated from the conductive connecting portion 138a to the total metal particles in the conductive resin layer 131b shown in Figures 6b, 6c, and 7b, which is 4.9% or more (e.g., 4.9%, 10.2%).

[0061] For example, the photographs in Figures 6a to 7b can be obtained by applying a cross-section of a multilayer capacitor to an analysis using at least one of the following: a micrometer, a TEM (transmission electron microscope), an AFM (atomic force microscope), a SEM (scanning electron microscope), an optical microscope, and a surface profiler. The above cross-section can be obtained by polishing or cutting the multilayer capacitor in the T-direction or W-direction so that the LW-section or LT-section containing the center of the multilayer capacitor is exposed. For example, the magnification of the optical microscope may be 200x for a 1608-size multilayer capacitor and 100x for a 3225-size multilayer capacitor.

[0062] The conductive resin layer 131b in Figure 7b can contain delamination and therefore can have a lower brightness than the conductive resin layer 131b in Figure 7a. For example, the identification of separated metal particles 137c and the identification of low brightness due to delamination in the photographs of Figures 6a to 7b can be performed by an image processing program (e.g., ImageJ program), the volume ratio (out rate) of separated metal particles 137c can be calculated based on the number of pixels in the image whose RGB coordinate values ​​belong to a specific range (e.g., R range of 150-165, G range of 75-85, B range of 45-55), and the presence or absence of delamination can be determined by whether the total number of pixels in the image within the external electrode whose brightness value is within a specific range is greater than or equal to a specific number.

[0063] Figures 8a and 8b are X-ray images showing the side view of a multilayer capacitor based on the volume ratio (Out Rate) of metal particles separated from the conductive connecting portion. Referring to Figure 8a, the volume ratio (Out Rate) of metal particles separated from the conductive connecting portion to the total metal particles in the conductive resin layer 131b of a multilayer capacitor according to one embodiment of the present invention may be less than 4.9% (e.g., 0.4%), and unlike the delamination space shown in Figure 8b where X-rays can penetrate, the area through which X-rays can penetrate may be nonexistent or very small. Since the images in Figures 8a and 8b are X-ray images, they can be obtained without polishing or cutting the multilayer capacitor.

[0064] Figures 9a and 9b are cross-sectional views showing the external electrodes before and after the formation of a conductive coupling portion in a multilayer capacitor according to one embodiment of the present invention.

[0065] Referring to Figure 9a, the initial conductive connector 138b does not necessarily have to be connected to the multiple metal particles 137b, and at least some of the multiple metal particles 137b may be coated with a metal material 136 having a standard electrode potential higher than the standard electrode potential of the multiple metal particles 137b (e.g., the standard electrode potential of copper). For example, the coated metal material 136 may be silver (Ag) and can form a core-shell structure together with the multiple metal particles 137b.

[0066] Referring to Figure 9b, the conductive connecting portion 138a can be fluid at a temperature higher than its melting point, and multiple metal particles 137a can be connected to each other via the coated metal material 136. In this case, the metal material 136 coated on the multiple metal particles 137a can increase its bonding to the conductive connecting portion 138a, thereby reducing the volume ratio of metal particles 137c separated from the conductive connecting portion 138a.

[0067] Figure 9b shows a structure in which the separated metal particles 137c are not coated, but at least some of the separated metal particles 137c can also be coated with the metal material 136. That is, the proportion of metal particles coated with the metal material 136 among the multiple metal particles 137b in Figure 9a is not particularly limited, and the coating ratio of the metal material 136 and the overall coating thickness can be adjusted by adjusting the ratio of the metal material 136 to the multiple metal particles 137b or by the paste mixing method, so that the volume ratio of metal particles 137c separated from the conductive connecting portion 138a is less than 4.9%.

[0068] On the other hand, the morphology of the multiple metal particles 137a and 137c is not limited to spherical, but may be elliptical, needle-shaped, or flake-shaped. The particle size of each of the multiple metal particles 137a and 137c is not particularly limited, but may be between 0.2 μm and 20 μm.

[0069] Figures 10a and 10b are photographs showing cross-sections of external electrodes based on the proportion of metal particles containing a shell (core-shell ratio) among multiple metal particles. Referring to Figure 10a, in a multilayer capacitor according to one embodiment of the present invention, the proportion of core-shell metal particles is relatively high (e.g., 100%), and the proportion of separated metal particles 137c is relatively lower than in the case where the proportion of core-shell metal particles is relatively low (e.g., 0%) as shown in Figure 10b.

[0070] Figure 11 is a graph showing the amount of gases such as carbon dioxide (CO2) generated at the external electrode with respect to temperature. Referring to Figure 11, the temperature during the reflow process is approximately 260 degrees Celsius, and the amount of gas generated (Abundance) when the proportion of metal particles in the core-shell structure is high (high core-shell ratio) is relatively lower than the amount of gas generated (Abundance) when the proportion of metal particles in the core-shell structure is low (low core-shell ratio). When the amount of gas generated (Abundance) is low, the possibility of delamination of the external electrode may be reduced.

[0071] As described above, embodiments of the present invention have been explained in detail, but the present invention is not limited by the embodiments described above and the accompanying drawings, but is limited by the claims provided. Therefore, within the scope of the technical idea of ​​the present invention as described in the claims, various forms of substitution, modification, and alteration are possible by persons with ordinary skill in the art, and these also fall within the scope of the present invention. According to this specification, the following items are also disclosed: [Item 1] A body comprising a laminated structure in which at least one first internal electrode and at least one second internal electrode are alternately stacked in a first direction with at least one dielectric layer in between, It includes first and second external electrodes, which are arranged in the main body spaced apart from each other so as to be connected to at least one first internal electrode and at least one second internal electrode, respectively. Each of the first and second external electrodes includes a conductive resin layer comprising a resin, a plurality of metal particles, and conductive connecting portions that connect some of the plurality of metal particles to each other. A multilayer capacitor in which, in the conductive resin layer, the volume ratio of metal particles separated from the conductive connecting portion to the sum of the plurality of metal particles and the conductive connecting portion is greater than 0% and less than 4.9%. [Item 2] Each of the first and second external electrodes is, The laminated capacitor according to item 1, further comprising a base electrode layer disposed between the conductive resin layer and the main body, and containing a metal material having a melting point higher than the melting point of the conductive connecting portion. [Item 3] The multilayer capacitor according to item 2, wherein each of the metal material of the base electrode layer and each of the plurality of metal particles contains copper (Cu). [Item 4] Each of the first and second external electrodes is, The multilayer capacitor according to item 2, further comprising an external plating layer containing a metallic material having a melting point lower than the melting point of the plurality of metal particles. [Item 5] Each of the first and second external electrodes is, The internal plating layer, which contains nickel (Ni), is disposed between the external plating layer and the conductive resin layer. The aforementioned external plating layer contains tin (Sn), as described in item 4, for the multilayer capacitor. [Item 6] The multilayer capacitor according to item 1, wherein the resin of the conductive resin layer comprises epoxy resin. [Item 7] The laminated capacitor according to item 6, wherein the mass ratio of the resin to the total metal contained in the conductive resin layer is 5% or more and 20% or less. [Item 8] The multilayer capacitor according to item 1, wherein at least some of the plurality of metal particles are coated with a metallic material having a standard electrode potential higher than the standard electrode potential of the plurality of metal particles. [Item 9] The aforementioned plurality of metal particles contain copper (Cu), A multilayer capacitor as described in item 8, wherein at least some of the plurality of metal particles are coated with silver (Ag). [Item 10] The multilayer capacitor according to item 9, wherein in the conductive resin layer, the mass ratio of the conductive connecting portion to the sum of the metal material coated on at least a portion of the plurality of metal particles and the plurality of metal particles is 4 / 6 or more and 7 / 3 or less. [Item 11] The laminated capacitor according to item 1, wherein in the conductive resin layer, the volume ratio of metal particles separated from the conductive connecting portion to the sum of the plurality of metal particles and the conductive connecting portion is less than 2.5%. [Item 12] The laminated capacitor according to item 11, wherein in the conductive resin layer, the volume ratio of metal particles separated from the conductive connecting portion to the sum of the plurality of metal particles and the conductive connecting portion is 2% or less. [Explanation of Symbols]

[0072] 100: Multilayer Capacitor 110: Main body 111: Dielectric layer 112: Upper cover layer 113: Lower cover layer 114: Margin Area 115: Core Area 116: Capacity area 121: 1st internal electrode 122:Second internal electrode 131: 1st external electrode 132:Second external electrode 131a, 132a: Base electrode layer 131b, 132b: Conductive resin layer 131c, 132c: Internal plating layer 131d, 132d: External plating layer 137a, 137c: Multiple metal particles 138a: Conductive connection part 139: Resin

Claims

1. A body comprising a laminated structure in which at least one first internal electrode and at least one second internal electrode are alternately stacked in a first direction with at least one dielectric layer in between, It includes first and second external electrodes, which are arranged in the main body spaced apart from each other so as to be connected to at least one first internal electrode and at least one second internal electrode, respectively. Each of the first and second external electrodes includes a conductive resin layer comprising a resin, a plurality of metal particles, and conductive connecting portions that connect some of the plurality of metal particles to each other. A multilayer capacitor in which, in the conductive resin layer, the volume ratio of metal particles separated from the conductive connecting portion to the sum of the plurality of metal particles and the conductive connecting portion is greater than 0% and less than 4.9%.

2. Each of the first and second external electrodes is, The laminated capacitor according to claim 1, further comprising a base electrode layer disposed between the conductive resin layer and the main body, and containing a metal material having a melting point higher than the melting point of the conductive connecting portion.

3. The multilayer capacitor according to claim 2, wherein each of the metal material of the base electrode layer and each of the plurality of metal particles contains copper (Cu).

4. Each of the first and second external electrodes is, The multilayer capacitor according to claim 2, further comprising an external plating layer containing a metallic material having a melting point lower than the melting point of the plurality of metal particles.

5. Each of the first and second external electrodes is, The external plating layer and the conductive resin layer are disposed between them and further comprise an internal plating layer containing nickel (Ni), The multilayer capacitor according to claim 4, wherein the external plating layer contains tin (Sn).

6. The laminated capacitor according to claim 1, wherein the resin of the conductive resin layer comprises an epoxy resin.

7. The laminated capacitor according to claim 6, wherein the mass ratio of the resin to the total metal contained in the conductive resin layer is 5% or more and 20% or less.

8. The multilayer capacitor according to claim 1, wherein at least a portion of the plurality of metal particles are coated with a metallic material having a standard electrode potential higher than the standard electrode potential of the plurality of metal particles.

9. The plurality of metal particles include copper (Cu), The multilayer capacitor according to claim 8, wherein at least a portion of the plurality of metal particles are coated with silver (Ag).

10. The laminated capacitor according to claim 9, wherein in the conductive resin layer, the mass ratio of the conductive connecting portion to the sum of the metal material coated on at least a portion of the plurality of metal particles and the plurality of metal particles is 4 / 6 or more and 7 / 3 or less.

11. The laminated capacitor according to claim 1, wherein in the conductive resin layer, the volume ratio of metal particles separated from the conductive connecting portion to the sum of the plurality of metal particles and the conductive connecting portion is less than 2.5%.

12. The laminated capacitor according to claim 11, wherein in the conductive resin layer, the volume ratio of metal particles separated from the conductive connecting portion to the sum of the plurality of metal particles and the conductive connecting portion is 2% or less.

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