Multilayer ceramic electronic components

Abstract

To provide a multilayer ceramic electronic component in which the heat resistance and moisture resistance characteristics are improved by including an external electrode having the excellent adhesive strength and impact resistance.SOLUTION: A multilayer ceramic electronic component according to one embodiment of the present invention includes: a ceramic body including dielectric layers and internal electrodes; first electrode layers disposed on the ceramic body and connected to the internal electrodes, respectively; and second electrode layers disposed on the first electrode layers, respectively, and respectively including a conductive metal including silver (Ag) and palladium (Pd), carbon materials, and glass, wherein an area ratio of the carbon materials in a cross section of at least a portion of each of the second electrode layers is 1 to 5%.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a multilayer ceramic electronic component.

Background Art

[0002] Among multilayer ceramic electronic components, a multilayer ceramic capacitor (MLCC) is an important chip component used in industries such as communication, computers, home appliances, and automobiles because it has the advantage of being small while ensuring high capacitance. In particular, it is also a core passive element used in various electrical, electronic, and information communication devices such as mobile phones, computers, and digital TVs.

[0003] Conventionally, in order to mount a multilayer ceramic capacitor on a substrate or the like, the external electrodes of the multilayer ceramic capacitor included a plated layer formed on an electrode layer. However, when mounting in a high-temperature environment, there were problems such as the occurrence of solder cracks and an increase in contact resistance due to warping of the substrate and oxidation of tin (Sn) contained in the plated layer.

[0004] To solve such problems, an external electrode structure composed of an electrode layer containing copper (Cu) and an electrode layer containing silver (Ag) and palladium (Pd) has been used. When using such external electrodes, a multilayer ceramic capacitor can be mounted on a substrate by using silver epoxy as a conductive adhesive instead of tin soldering.

[0005] However, with such a secondary external electrode structure, a peel-off phenomenon may occur in which the electrode layers separate or peel from each other, and there is a risk of inferior heat resistance. Therefore, there is a need for a multilayer ceramic capacitor with improved adhesion strength, heat resistance, and moisture resistance between the electrodes.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One of the objectives of the present invention is to provide a multilayer ceramic electronic component with improved heat resistance and moisture resistance by including an external electrode with excellent bonding strength and impact resistance.

[0007] However, the objectives of the present invention are not limited to those described above and can be more easily understood in the process of describing specific embodiments of the present invention. [Means for solving the problem]

[0008] One embodiment of the present invention provides a multilayer ceramic electronic component comprising: a ceramic body including a dielectric layer and internal electrodes; a first electrode layer disposed on the ceramic body and connected to the internal electrodes; and a second electrode layer disposed on the first electrode layer and including a conductive metal containing silver (Ag) and palladium (Pd), a carbon material, and glass, wherein the area ratio occupied by the carbon material in at least a portion of the cross-section of the second electrode layer is 1 to 5%. [Effects of the Invention]

[0009] One of the various effects of the present invention is that by including external electrodes with excellent bonding strength and impact resistance, it is possible to provide multilayer ceramic electronic components with improved heat resistance and moisture resistance. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing a multilayer ceramic electronic component relating to one embodiment of the present invention. [Figure 2] This is a cross-sectional view along the line I-I' in Figure 1. [Figure 3] This is an enlarged view showing region P in Figure 2. [Figure 4] This is an enlarged view showing the Q region in Figure 3. [Figure 5] These are images of cross-sections of the first and second electrode layers analyzed using a scanning electron microscope (SEM). [Figure 6] This is an image showing the carbon element mapped using energy-dispersive spectroscopy (EDS). [Figure 7] This graph shows the results of Raman analysis on the second electrode layer. [Figure 8] This image shows the ion migration phenomenon, which is observed in proportion to the surface area of ​​carbon material. [Figure 9] This image shows the morphology of how external electrodes are fractured by external stress, depending on the area ratio of the carbon material. [Figure 10] This graph shows the equivalent series resistance (ESR) of multilayer ceramic electronic components evaluated according to the area ratio of carbon material. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to specific embodiments and accompanying drawings. However, 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 give a more complete explanation of the present invention to those who are ordinary in the art. Accordingly, the shapes and sizes of elements in the drawings may be enlarged or reduced (or highlighted or simplified) for a clearer explanation, and elements indicated by the same reference numerals in the drawings are the same elements.

[0012] Furthermore, in order to clearly illustrate the present invention in the drawings, parts unrelated to the explanation have been omitted, and the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation; therefore, the present invention is not necessarily limited to what is shown. Components with the same function within the scope of the same concept will be described using the same reference numerals. Furthermore, throughout the specification, when a part "includes" a certain component, this does not mean that other components are excluded, but rather that other components may be further included, unless otherwise stated.

[0013] In the drawing, the first direction can be defined as the lamination direction or the thickness T direction, the second direction as the length L direction, and the third direction as the width W direction.

[0014] FIG. 1 is a perspective view showing a multilayer ceramic electronic component according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line I-I' of FIG. 1, FIG. 3 is an enlarged view showing an enlarged P region of FIG. 2, and FIG. 4 is an enlarged view showing an enlarged Q region of FIG. 3.

[0015] Hereinafter, referring to FIGS. 1 to 4, a multilayer ceramic electronic component 100 according to an embodiment of the present invention will be described.

[0016] A multilayer ceramic electronic component 100 according to an embodiment of the present invention includes a ceramic body 110 including a dielectric layer 111 and internal electrodes 121 and 122, a first electrode layer 131a and 131b disposed on the ceramic body 110 and connected to the internal electrodes 121 and 122, and a second electrode layer 132a and 132b disposed on the first electrode layer 131a and 131b and including a conductive metal 32a containing silver (Ag) and palladium (Pd), a carbon material 32b, and a glass 32c. The area ratio occupied by the carbon material 32b in at least a part of the cross section of the second electrode layer 132a and 132b satisfies 1 to 5%.

[0017] The specific shape of the ceramic body 110 is not particularly limited, but as shown in the drawing, the ceramic body 110 can have a hexahedron shape or a shape similar thereto. Due to the shrinkage of the ceramic powder contained in the ceramic body 110 and the polishing of the corners during the firing process, the ceramic body 110 does not have a perfect hexahedron shape with straight lines, but can have a substantially hexahedron shape.

[0018] The ceramic body 110 can have a first surface and a second surface 1 and 2 facing each other in a first direction, a third surface and a fourth surface 3 and 4 connected to the first surface and the second surface 1 and 2 and facing each other in a second direction, and a fifth surface and a sixth surface 5 and 6 connected to the first surface and the second surface 1 and 2 and also connected to the third surface and the fourth surface 3 and 4 and facing each other in a third direction.

[0019] The ceramic body 110 can be constructed by alternately stacking dielectric layers 111 and internal electrodes 121 and 122. The multiple dielectric layers 111 forming the ceramic body 110 are in a fired state, and the boundaries between adjacent dielectric layers 111 can be so integrated that they are difficult to confirm without using a scanning electron microscope (SEM).

[0020] The dielectric layer 111 can be formed by firing a ceramic green sheet containing ceramic powder, an organic solvent, and a binder. The ceramic powder is not particularly limited as long as sufficient capacitance can be obtained. For example, barium titanate (BaTiO3) material, strontium titanate (SrTiO3) material, etc. can be used, but the present invention is not limited thereto.

[0021] In this case, the thickness of the dielectric layer 111 can be 10 μm or less, taking into consideration the size and capacitance of the ceramic body 110, and can be 0.6 μm or less, more preferably 0.4 μm or less, in order to miniaturize and increase the capacitance of the multilayer ceramic electronic component 100, but the present invention is not limited thereto.

[0022] Here, the thickness of the dielectric layer 111 can refer to the average thickness of the dielectric layer 111 placed between the internal electrodes 121 and 122. The thickness of the dielectric layer 111 can be measured by scanning the cross-sections of the ceramic body 110 in the first and second directions using a scanning electron microscope at 10,000x magnification. More specifically, the thickness of any dielectric layer 111 can be measured at multiple points, for example, 30 points equally spaced in the second direction, and the average value can be calculated. Furthermore, by extending such average value measurements to a large number of dielectric layers 111, the average thickness of the dielectric layer 111 can be further generalized.

[0023] The ceramic body 110 may include a capacitance forming section disposed inside the body 110 and comprising a plurality of first internal electrodes 121 and a plurality of second internal electrodes 122 arranged facing each other with a dielectric layer 111 in between, thereby forming a capacitance; a first cover section 112 disposed above the capacitance forming section; and a second cover section 113 disposed below the capacitance forming section. The first cover section 112 and the second cover section 113 can be formed by stacking a single dielectric layer or two or more dielectric layers on the upper and lower surfaces of the capacitance forming section in a first direction, and can basically serve to prevent damage to the internal electrodes due to physical or chemical stress. The first and second cover sections 112 and 113 may have the same configuration as the dielectric layer 111, except that they do not include internal electrodes. Each of the first and second cover sections 112 and 113 may have a thickness of 20 μm or less, but the present invention is not limited thereto.

[0024] The internal electrodes 121 and 122 can be arranged alternately with the dielectric layer 111, and multiple first internal electrodes 121 and multiple second internal electrodes 122 can be arranged facing each other with the dielectric layer 111 in between. That is, the first and second internal electrodes 121 and 122 are pairs of electrodes having different polarities and can be formed to be alternately exposed on the third and fourth surfaces 3 and 4 of the ceramic body 110 along the stacking direction of the dielectric layer 111.

[0025] For example, each of the multiple first internal electrodes 121 can be exposed on the third surface 3 of the ceramic body 110, separated from the fourth surface 4. Furthermore, each of the multiple second internal electrodes 122 can be exposed on the fourth surface 4 of the ceramic body 110, separated from the third surface 3. The multiple first internal electrodes 121 and the multiple second internal electrodes 122 can be electrically isolated from each other by a dielectric layer 111 placed between them. The multiple first internal electrodes 121 and the multiple second internal electrodes 122 can be stacked alternately in a first direction, but are not limited to this; they may also be stacked alternately in a third direction.

[0026] The internal electrodes 121 and 122 can be formed by printing a conductive paste for internal electrodes containing a conductive metal to a predetermined thickness onto a ceramic green sheet. While screen printing or gravure printing can be used as the printing method for the conductive paste for internal electrodes, the present invention is not limited thereto.

[0027] The conductive metals contained in the internal electrodes 121 and 122 may be one or more of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof, but the present invention is not limited thereto.

[0028] In this case, the thickness of the internal electrodes 121 and 122 can be 10 μm or less, taking into consideration the size and capacitance of the ceramic body 110, and can be 0.6 μm or less, more preferably 0.4 μm or less, in order to miniaturize and increase the capacitance of the multilayer ceramic electronic component 100, but the present invention is not limited thereto.

[0029] Here, the thickness of internal electrodes 121 and 122 can refer to the average thickness of internal electrodes 121 and 122. The average thickness of internal electrodes 121 and 122 can be measured by scanning the cross-sections of the ceramic body 110 in the first and second directions using a scanning electron microscope at 10,000x magnification. More specifically, the thickness can be measured at a number of points on any internal electrode, for example, at 30 points equally spaced in the second direction, and the average value can be calculated. By extending such average value measurements to a number of internal electrodes, the average thickness of the internal electrodes can be further generalized.

[0030] These first and second internal electrodes 121 and 122 can be electrically connected to the first and second external electrodes 130a and 130b, respectively, via first electrode layers 131a and 131b arranged on the third and fourth surfaces 3 and 4 of the ceramic body 110.

[0031] Therefore, when a voltage is applied to the first and second external electrodes 130a and 130b, charge accumulates between the first and second internal electrodes 121 and 122 that face each other, and in this case, the capacitance of the multilayer ceramic electronic component 100 becomes proportional to the area of ​​the overlapping region of the first and second internal electrodes 121 and 122.

[0032] The external electrodes 130a and 130b are positioned on the third and fourth surfaces 3 and 4 of the ceramic body 110 and can extend to parts of the first, second, fifth, and sixth surfaces 1, 2, 5, and 6, respectively. The external electrodes 130a and 130b may include first external electrodes 130a and second external electrodes 130b that are connected to a plurality of first internal electrodes 121 and a plurality of second internal electrodes 122, respectively. The external electrodes 130a and 130b may be formed using any material that has electrical conductivity, such as metal, and the specific material may be determined considering electrical properties, structural stability, etc. Furthermore, they may have a multilayer structure.

[0033] For example, the first and second external electrodes 130a and 130b may each include a first electrode layer 131a and 131b, which are arranged on the ceramic body 110 and connected to the first and second internal electrodes 121 and 122, respectively, and a second electrode layer 132a and 132b, which are arranged on the first electrode layers 131a and 131b.

[0034] In this case, the first electrode layers 131a and 132b can mechanically bond the ceramic body 110 to the external electrodes 130a and 130b. The first electrode layers 131a and 131b are connected to a plurality of first and second internal electrodes 121 and 122 that are alternately exposed on the third and fourth surfaces 3 and 4 of the ceramic body 110, respectively, thereby ensuring electrical conductivity between the first and second external electrodes 130a and 130b and the first and second internal electrodes 121 and 122. On the other hand, the thickness of the first electrode layers 131a and 131b does not need to be particularly limited, but can be, for example, 5 to 30 μm.

[0035] In this case, the first electrode layers 131a and 131b may include a conductive metal and glass. The conductive metal in the first electrode layers 131a and 131b may include, for example, copper (Cu). The first electrode layers 131a and 131b can be formed by dipping the third and fourth surfaces 3 and 4 of the ceramic body 110 into a conductive paste containing a conductive metal and glass, and then firing it. Alternatively, they can be formed by transferring a sheet containing a conductive metal and glass.

[0036] The second electrode layers 132a and 132b are arranged on the first electrode layers 131a and 131b and may contain silver (Ag) and palladium (Pd) as the conductive metal 32a. The second electrode layers 132a and 132b are electrically connected to the first electrode layers 131a and 131b and, by containing silver (Ag) and palladium (Pd), can prevent oxidation and prevent the penetration of moisture and hydrogen from the outside. Furthermore, by applying a conductive adhesive such as silver epoxy (Ag epoxy) to the second electrode layers 132a and 132b using the conductive metal 32a containing silver (Ag), the multilayer ceramic electronic component 100 can be mounted on a ceramic substrate without using solder containing tin (Sn). This solves the problem of solder cracks occurring due to stress caused by the difference in thermal expansion coefficients between the external electrode and the solder during high-temperature-low-temperature cycles.

[0037] In this case, if the conductive metal 32a contained in the second electrode layers 132a and 132b consists only of silver (Ag), or if the silver (Ag) content is too high, ion migration may occur in a high-temperature environment. In this case, the occurrence of ion migration can be prevented by further including palladium (Pd) in the second electrode layers 132a and 132b. Here, palladium (Pd) can be replaced or mixed with other metals that can prevent ion migration, such as platinum (Pt) and / or gold (Au).

[0038] When the glass 32c is coated with a conductive paste and fired to form the second electrode layers 132a and 132b, the density of the second electrode layers 132a and 132b can be increased by controlling the sintering rate of the conductive metal 32a and filling void spaces when the conductive metal 32a shrinks during the sintering process. This effectively suppresses the penetration of moisture from the outside.

[0039] The glass 32c component can be a mixture of oxides and is not particularly limited, but may be one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide. The transition metal is selected from the group consisting of zinc (Zn), titanium (Ti), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal is selected from the group consisting of lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be one or more selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0040] The carbon material 32b can be any allotrope of carbon, and may even be a non-conductive carbon material 32b. While conductive carbon material 32b has the advantage of superior electrical conductivity, a non-conductive carbon material 32b is also acceptable as long as it can prevent ion migration or improve adhesion strength.

[0041] For example, the carbon material 32b may include one or more of graphene, carbon nanotubes, fullerenes, and black carbon, but the present invention is not limited thereto. Since the carbon material 32b is stable even at high temperatures and has excellent mechanical properties, when the carbon material 32b is uniformly distributed within the second electrode layers 132a and 132b, it can absorb external shocks. Furthermore, because it has a low rate of change with temperature, it can improve the strength and heat resistance of the multilayer ceramic electronic component 100.

[0042] The second electrode layers 132a and 132b can be formed by applying and drying a conductive paste containing a conductive metal including silver (Ag) and palladium (Pd), a carbon material, and glass, and then firing it at a low temperature of 600-700°C for 1-2 hours.

[0043] Figure 5 shows an image of the cross-section of the first and second electrode layers analyzed using a scanning electron microscope (SEM). More specifically, it is an image of the analysis of a region with a length in the second direction × length in the third direction = 135 μm × 95 μm in the cross-section of the multilayer ceramic electronic component 100 passing through the center in the first direction. Figure 6 shows an image of carbon element mapping using energy-dispersive spectroscopy (EDS). More specifically, it is an image of carbon (C) element mapping in a region of 60 μm × 40 μm in length in the second direction × length in the third direction = scanning electron microscope (SEM) images obtained by scanning the second and third cross-sections of the second electrode layers 132a and 132b at 2000x magnification. In the image, brighter areas indicate a higher carbon element content.

[0044] Figures 5 and 6 show that the area occupied by the carbon material 32b within the second electrode layers 132a and 132b can be measured, and it can be seen that the carbon material 32b is uniformly distributed within the second electrode layers 132a and 132b.

[0045] According to one embodiment of the present invention, the area ratio occupied by the carbon material 32b in at least a portion of the cross-section of the second electrode layers 132a and 132b can be 1 to 5%.

[0046] As an example of a method for measuring the area ratio occupied by the carbon material 32b, as shown in Figures 5 and 6, the second electrode layers 132a and 132 can be photographed using a scanning electron microscope (SEM) in the second and third cross-sections passing through the center of the first direction of the multilayer ceramic electronic component 100, or in the first and second cross-sections passing through the center of the third direction of the multilayer ceramic electronic component 100, and the carbon element can be mapped using energy-dispersive spectroscopy (EDS).

[0047] When an electric field is applied to the multilayer ceramic electronic component 100, ion migration occurs, in which silver (Ag) contained in the second electrode layers 132a and 132b ionizes and moves to the first electrode layers 131a and 131b, which can reduce reliability. In this case, if the area ratio occupied by the carbon material 32b in at least a portion of the cross-section of the second electrode layers 132a and 132b is 1 to 5%, ion migration can be prevented and reliability can be improved. This is because the carbon material 32b contained in the second electrode layers 132a and 132b reduces the relative volume of silver (Ag), and the carbon material 32b effectively suppresses the movement of silver (Ag).

[0048] Furthermore, if the area ratio occupied by the carbon material 32b in at least a portion of the cross-section of the second electrode layers 132a and 132b satisfies the above conditions, the carbon material 32b will be uniformly distributed within the second electrode layers 132a and 132b, thereby improving the bonding strength and impact resistance. Depending on the type, the carbon material 32b has excellent elasticity, impact resistance, and stiffness that resists deformation, and therefore plays a role in absorbing and mitigating external stresses, thereby improving the bonding strength and impact resistance of the second electrode layers 132a and 132b.

[0049] If the area ratio of carbon material 32b in at least a portion of the cross-section of the second electrode layers 132a and 132b is less than 1%, the heat resistance may decrease due to insufficient distribution of carbon material 32b, and the effect of suppressing silver (Ag) ion migration may decrease. In addition, the impact resistance may decrease due to insufficient distribution of carbon material 32b, which may cause the first electrode layers 131a and 131b to break or the second electrode layers 132a and 132b to peel off during the evaluation of adhesion strength.

[0050] If the area ratio occupied by the carbon material 32b in at least a portion of the cross-section of the second electrode layers 132a and 132b exceeds 5%, the carbon material 32b may not be uniformly distributed within the second electrode layers 132a and 132b during firing, causing the carbon material 32b to stick together and reducing the bonding strength. In particular, if the area ratio occupied by the carbon material 32b is 10% or more, the carbon material 32b may stick together during firing, forming a large number of voids, or blistering may occur at the external electrode. This may cause a peel-off phenomenon to occur between the first electrode layers 131a and 131b and the second electrode layers 132a and 132b, potentially leading to a problem where the adhesion strength with the silver epoxy used when mounting the multilayer ceramic electronic component 100 onto the ceramic substrate is reduced.

[0051] The carbon material 32b described above can have a variety of shapes depending on the type of carbon allotrope, and can be spherical or plate-shaped, but the present invention is not limited thereto and can include all spherical and plate-shaped carbon material 32b. In particular, when the carbon material 32b contains graphene, the graphene can be dispersed in a plate-like manner, but the present invention is not limited thereto.

[0052] In one embodiment of the present invention, the diameter of the carbon material 32b can be 0.25 μm to 4 μm. The diameter of the carbon material 32b can be measured by imaging the second electrode layers 132a and 132b in the second and third cross-sections, or the first and second cross-sections, using a scanning electron microscope (SEM), mapping the carbon elements using energy-dispersive spectroscopy (EDS), and then measuring the diameter using a program within the EDS.

[0053] In one embodiment of the present invention, the carbon material 32b has a cross-sectional area of ​​2500 μm². 2 Ten or more can be arranged per unit. Here, the above cross-section can mean the first and second direction cross-sections or the second and third direction cross-sections of the second electrode layers 132a, 132b for measuring the area ratio occupied by the carbon material 32b. The measurement of the carbon material 32b is not particularly limited, but for example, it can be measured within a 50 μm × 50 μm (width × height) area of ​​the second electrode layers 132a, 132b, but the present invention is not limited thereto.

[0054] As an example of a method for measuring the number of carbon material 32b, the number of carbon material 32b can be measured by mapping the carbon elements using energy-dispersive spectroscopy (EDS) within a 50 μm × 50 μm (width × height) area of ​​the second electrode layers 132a and 132b extracted from an image obtained by scanning the above cross-section using a scanning electron microscope (SEM) or transmission electron microscope (TEM).

[0055] Figure 7 is a graph showing the results of Raman analysis of the second electrode layer.

[0056] In one embodiment of the present invention, when Raman analysis is performed on the second electrode layers 132a and 132b, two peaks can be detected. These two peaks can be detected in the D band and the G band, and the G band is 1580 cm⁻¹. -1 Nearby, the D band is 1350 cm. -1 It can appear in the vicinity. When Raman analysis is performed on the second electrode layers 132a and 132b, the reason why two peaks are detected is that the second electrode layers 132a and 132b contain graphene, which results in a Raman analysis graph that differs from that of other carbon materials. Embodiment

[0057] Table 1 below shows the experimental results of measuring ion migration, adhesion strength, and the coefficient of variation (CV) of ESR (Equivalent Series Resistance) according to the area ratio occupied by the carbon material in the second and third cross-sections of the second electrode layers 132a and 132b.

[0058] All samples in Table 1 below are sample chips (MLCCs) containing external electrodes 130a and 130b, on which second electrode layers 132a and 132b containing silver (Ag) and palladium (Pd) are formed on first electrode layers 131a and 132a containing copper (Cu). They were manufactured under the same conditions except for varying the area ratio of the carbon material.

[0059] <Measurement of the area ratio of carbon material> The area percentage occupied by the carbon material was measured after polishing the sample chip to the center in the first direction, then imaging the cross-sections of the second electrode layer in the second and third directions using a scanning electron microscope (SEM), and finally performing EDS (Energy Dispersive X-ray Spectroscopy) analysis. At this time, the area percentage occupied by the carbon material was measured by mapping the carbon (C) element under conditions of an acceleration voltage of 15kV and a working distance (WD) of 15mm.

[0060] More specifically, referring to Figure 6, scanning electron microscope (SEM) images of the second and third cross-sections scanned at 2000x magnification were analyzed using EDS. After mapping the element carbon (C) to a region with a length in the second direction × length in the third direction = 60 μm × 40 μm, the area percentage occupied by the carbon material in the above region was measured using a program within the EDS.

[0061] Furthermore, the sample chip was heat-treated at 700°C for 2 hours to volatilize organic matter, and then Raman analysis was performed on the second electrode layer. At this time, as shown in Figure 7, 1580 cm² was used. -1 Nearby, G-band, 1350cm -1 A D-band was detected in the vicinity. This confirmed that the second electrode layer contains a carbon material, more specifically, graphene.

[0062] <Evaluation of ion migration> Figure 8 shows an image of the ion migration phenomenon, which is observed in proportion to the area ratio of carbon material.

[0063] Each of the fabricated sample chips was evaluated for ion migration using an ion migration measuring instrument. The test conditions were a relative humidity of 85%, a temperature of 85°C, a DC voltage of 10 V, and a DC current of 1 A, and the evaluation was performed by the water drop (1000 μL) acceleration test method. Then, as shown in Fig. 8, the time required for ion migration to occur in each sample chip was measured.

[0064] <Evaluation of Adhesion Strength> Fig. 9 is an image obtained by photographing the form in which the external electrode is broken by an external stress according to the area ratio of the carbon material.

[0065] The adhesion strength of each sample chip was determined by applying a force in a direction parallel to the substrate in a state where each sample chip was mounted on the substrate with a silver epoxy (Ag epoxy) conductive adhesive (Conductive Glue) and measuring the force applied when it was broken. Furthermore, the fracture mode of each sample chip was observed.

[0066] <Evaluation of ESR Change> Fig. 10 is a graph evaluating the equivalent series resistance (ESR) of a multilayer ceramic electronic component according to the area ratio of the carbon material.

[0067] For each sample, the ESR (equivalent series resistance) was measured at the self-resonance frequency using an LCR meter and shown in Fig. 10. In Table 1 below, the coefficient of variation (CV) of the ESR was measured and shown.

[0068]

Table 1

[0069] T Referring to Table 1 above and Fig. 8, in the case of sample numbers 1* and 2* where the area ratio of the carbon material is less than 1%, it was confirmed that ion migration of silver (Ag) metal particles occurred within 2 minutes and the prevention effect of ion migration decreased.

[0070] In contrast, for samples 3-5, the time required for ion migration to occur was 5 minutes or more, confirming that ion migration was effectively suppressed.

[0071] Referring to Table 1 and Figure 9 above, it was confirmed that in the case of samples 1* and 2*, where the area percentage of carbon material was less than 1%, cracks occurred in the sample chip or the first or second electrode layer broke during the evaluation of the bonding strength, resulting in a peel-off phenomenon between the first and second electrode layers. This indicates that when the area percentage of carbon material is less than 1%, the impact resistance of the second electrode layer decreases.

[0072] In the case of sample number 6*, where the area ratio of carbon material exceeds 5%, it was confirmed that the carbon material was not uniformly distributed within the second electrode layer during firing, causing the carbon material to stick together and reducing the bonding strength. This indicates that a peel-off phenomenon occurs in the second electrode layer when evaluating the bonding strength.

[0073] In particular, in the case of sample number 7*, where the area proportion occupied by carbon material was 10%, it was confirmed that during firing, the carbon material adhered to each other, forming a large number of voids, and blistering occurred at the external electrode, preventing adhesion between the first and second electrode layers. As a result, the external electrode was not formed by firing due to the voids and blisters.

[0074] In contrast, for samples 3-5, where the area proportion of carbon material was 1-5%, the bonding strength was good. When evaluating the bonding strength, it was confirmed that the sample chip and its external electrodes were not destroyed, and only the conductive adhesive (Glue) used for mounting was destroyed.

[0075] Furthermore, referring to Table 1 and Figure 10 above, it was confirmed that in the case of sample number 6*, where the area proportion of carbon material exceeds 7%, the volume fraction occupied by glass and carbon material becomes excessively high, and the coefficient of variation (CV) increases. This is because the carbon distribution is not uniform and acts as noise.

[0076] Therefore, it was confirmed that the area ratio occupied by carbon material in at least a portion of the cross-section of the second electrode layer has a significant effect on the mechanical and electrical properties of the multilayer ceramic electronic component, and that when the above range is met, ion migration can be effectively suppressed, thereby improving the reliability of the multilayer ceramic electronic component by improving the adhesion strength and impact resistance of the external electrode.

[0077] The present invention is not limited by the embodiments described above or the accompanying drawings, but is limited by the claims provided herein. 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. [Explanation of symbols]

[0078] 100: Multilayer ceramic electronic components 110: Ceramic body 111: Dielectric layer 112: First Cover Section 113: Second Cover Section 121: 1st internal electrode 122:Second internal electrode 130a: 1st external electrode 130b: 2nd external electrode 131a, 131b: first electrode layer 132a, 132b: Second electrode layer 32a: Conductive metal 32b: Carbon material 32c: Glass

Claims

1. A ceramic body including a dielectric layer and internal electrodes, A first electrode layer is disposed on the ceramic body and connected to the internal electrode, The first electrode layer is disposed on the first electrode layer and includes a second electrode layer comprising a conductive metal containing silver (Ag) and palladium (Pd), a carbon material, and glass, A multilayer ceramic electronic component in which the area ratio occupied by the carbon material in at least a portion of the cross-section of the second electrode layer is 1 to 5%.

2. The multilayer ceramic electronic component according to claim 1, wherein the carbon material comprises one or more of graphene, carbon nanotubes, fullerenes, and black carbon.

3. The ceramic body includes a first and second surface facing in the first direction, a third and fourth surface facing in the second direction, and a fifth and sixth surface facing in the third direction. The multilayer ceramic electronic component according to claim 1, wherein the area ratio occupied by the carbon material is 1 to 5% in at least one of the first and second direction cross-sections and the second and third direction cross-sections of the second electrode layer.

4. The multilayer ceramic electronic component according to claim 1, wherein the carbon material is spherical or plate-shaped.

5. The multilayer ceramic electronic component according to claim 4, comprising all of the aforementioned spherical and plate-shaped carbon materials.

6. The multilayer ceramic electronic component according to claim 1, wherein the diameter of the carbon material is 0.25 μm to 4 μm.

7. The carbon material has a cross-sectional area of ​​2500 μm². ２ The multilayer ceramic electronic component according to claim 1, wherein 10 or more are arranged per unit.

8. The multilayer ceramic electronic component according to claim 7, wherein the area is 50 μm × 50 μm (width × height).

9. The multilayer ceramic electronic component according to claim 1, wherein the conductive metal of the second electrode layer further comprises one or more of platinum (Pt) and gold (Au).

10. The first electrode layer comprises a conductive metal and glass. The multilayer ceramic electronic component according to claim 1, wherein the conductive metal of the first electrode layer includes copper (Cu).

11. The multilayer ceramic electronic component according to any one of claims 1 to 10, wherein when Raman analysis is performed on the second electrode layer, two peaks are detected.

12. The multilayer ceramic electronic component according to claim 11, wherein the carbon material includes graphene.

13. The multilayer ceramic electronic component according to claim 11, wherein the two peaks are detected in the D band and the G band.

Images