Ceramic electronic components

Abstract

This invention provides a ceramic electronic component that can reduce the risk of radiation cracking by lowering the heat treatment temperature, and reduces the temperature dependence of capacitance realization because it is not constrained by the fluid dynamics properties of the binder when realizing substantially uniform thickness of the external electrode, and density realization is almost complete. [Solution] This disclosure relates to a ceramic electronic component comprising a body including a dielectric layer and an internal electrode, and an external electrode disposed on the body, wherein the external electrode comprises copper and glass, and in a cross-section in the length and thickness directions, the area from the inner surface of the external electrode to a point 7 μm thick of the external electrode is defined as a first region, and the area from the point 7 μm thick of the external electrode to the outer surface of the external electrode is defined as a second region, wherein the area ratio of the glass to the copper in the second region is even smaller than the area ratio of the glass to the copper in the first region.

Description

Technical Field

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[0001] The present disclosure relates to ceramic electronic components, for example, multilayer ceramic capacitors (MLCCs).

Background Art

[0002] Recently, the development of ultra-small MLCCs has been demanded due to the miniaturization, thinning, shorting, and lightening of electronic products. For this purpose, various material process technologies are continuously being developed. That is, many studies are being conducted on the development of ultra-small and highly reliable MLCC products.

[0003] On the other hand, most of the external electrodes of MLCCs are formed by the dipping method. In this case, firing of the external electrodes is required. For example, a method such as applying an external electrode paste to a ceramic body using dipping and then firing can be used. <00000​​​​​​​​​​​​​​​​​​​Another of the various objectives of this disclosure is to provide ceramic electronic components that are not constrained by the fluorochemical properties of the binder when achieving substantially uniform thickness of the external electrodes.

[0008] Another of the various objectives of this disclosure is to provide ceramic electronic components that can reduce the temperature dependence of capacitance realization because density realization is almost complete. [Means for solving the problem]

[0009] One of the various solutions proposed in this disclosure is to form a bonding layer on a separately formed external electrode and use this to perform heat treatment bonding to the ceramic body.

[0010] For example, a ceramic electronic component according to one example includes a body containing a dielectric layer and internal electrodes, external electrodes placed on the body, and a bonding layer placed between the body and the external electrodes, wherein the bonding layer may be thinner than the external electrodes.

[0011] For example, a ceramic electronic component according to one example includes a body containing a dielectric layer and internal electrodes, and external electrodes disposed on the body, the external electrodes containing copper and glass, and when the area from the inner surface of the external electrodes to a point 7 μm thick is defined as the first region in the length and thickness directions, and the area from the point 7 μm thick to the outer surface of the external electrodes is defined as the second region, the area ratio of glass to copper in the second region may be even smaller than the area ratio of glass to copper in the first region. [Effects of the Invention]

[0012] One of the various effects of this disclosure is the ability to provide ceramic electronic components that can reduce the heat treatment temperature and eliminate the risk of radiation cracking.

[0013] Another of the various effects of this disclosure is that it is possible to provide ceramic electronic components that are not constrained by the fluid dynamics properties of the binder when achieving substantially uniform thickness of the external electrodes.

[0014] Another benefit of this disclosure is that, since density realization is almost complete, it is possible to provide ceramic electronic components that reduce the temperature dependence of capacity realization. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic perspective view showing an example of a ceramic electronic component. [Figure 2] Figure 1 is a schematic cross-sectional view of the ceramic electronic component cut along the line I-I'. [Figure 3] This is a schematic perspective view showing another example of a ceramic electronic component. [Figure 4] Figure 3 is a schematic cross-sectional view of the ceramic electronic component cut along the line II-II'. [Figure 5] This is a schematic perspective view showing another example of a ceramic electronic component. [Figure 6] Figure 5 is a schematic cross-sectional view of the ceramic electronic component cut along the line III-III'. [Figure 7] This is a schematic perspective view showing another example of a ceramic electronic component. [Figure 8] Figure 7 is a schematic cross-sectional view of the ceramic electronic component cut along the line IV-IV'. [Figure 9] This is a schematic cross-sectional view showing an example of a silica coating layer being formed on a copper electrode. [Figure 10] This is a schematic cross-sectional SEM (Scanning Electron Microscope) image showing the formation of a bonding layer at the interface between the main body and the external electrode. [Figure 11] This is a cross-sectional SEM image that schematically shows the distribution of copper and glass within the external electrode when the bonding layer is not included. [Figure 12] This is a cross-sectional SEM image that schematically shows the distribution of copper and glass within the external electrode when a bonding layer is included. [Figure 13]This is a cross-sectional SEM photograph schematically showing the distribution of copper and glass in an external electrode when a bonding layer is included.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, the present disclosure will be described with reference to the accompanying drawings. The shape, size, etc. of elements in the drawings can be enlarged, reduced (or emphasized or simplified) for a clearer explanation.

[0017] FIG. 1 is a perspective view schematically showing a ceramic electronic component according to an example, and FIG. 2 is a schematic cross-sectional view of the ceramic electronic component of FIG. 1 cut along the line I-I'.

[0018] Referring to the drawings, a ceramic electronic component 100A according to an example includes a main body 110 including a dielectric layer 111 and internal electrodes 121 and 122, external electrodes 131 and 132 disposed on the main body 110, and bonding layers 151 and 152 disposed between the main body 110 and the external electrodes 131 and 132. For example, the bonding layers 151 and 152 can exist in a very thin film form at the interface between the main body 110 and the external electrodes 131 and 132.

[0019] The main body 110 can have a shape close to a rectangular parallelepiped having a first surface (or left-side surface) and a second surface (or right-side surface) facing each other with respect to the X-direction (or length direction), a third surface (or front-side surface) and a fourth surface (or rear-side surface) facing each other with respect to the Y-direction (or width direction), and a fifth surface (or upper surface) and a sixth surface (or lower surface) facing each other with respect to the Z-direction (or thickness direction). If necessary, the angular outer shape of the main body 110, for example, the corner portions can be polished round by a polishing process or the like. If necessary, the angular outer shape of the outer electrodes 131 and 132, for example, the corner portions can also have a round shape and can also have a concave and / or convex shape in some regions.

[0020] The main body 110 can have dielectric layers 111 and internal electrodes 121 and 122 alternately stacked in the Z-direction. The multiple dielectric layers 111 forming the main body 110 are in a fired state, and the boundaries between adjacent dielectric layers 111 can be integrated to such an extent that they are difficult to confirm without using a scanning electron microscope (SEM).

[0021] The dielectric layer 111 can be formed by firing a ceramic green sheet containing ceramic powder, an organic solvent, and an organic binder. The ceramic powder is a material with a high dielectric constant, and is not limited to this, but for example, barium titanate (BaTiO3) based materials and strontium titanate (SrTiO3) based materials can be used. Thus, the dielectric layer 111 can contain ferroelectric materials, but is not necessarily limited to them. On the other hand, the dielectric layer 111 can be in a state where multiple layers are stacked and sintered, and these can be integrated to such an extent that the boundaries between adjacent layers are difficult to visually confirm.

[0022] The internal electrodes 121 and 122 can be formed from a conductive paste containing a conductive metal. For example, the conductive paste can be printed onto a ceramic green sheet forming the dielectric layer 111 by a printing method such as screen printing or gravure printing, thereby printing the internal electrodes 121 and 122. By alternately stacking the ceramic green sheets on which the internal electrodes 121 and 122 are printed and firing them, the above-described body 110 can be formed. The conductive metal may include, but is not limited to, nickel (Ni), copper (Cu), palladium (Pd), and / or alloys thereof.

[0023] The internal electrodes 121 and 122 may include a plurality of first internal electrodes 121 and a plurality of second internal electrodes 122. The plurality of first and second internal electrodes 121 and 122 may be arranged separated from each other with a dielectric layer 111 in between. The plurality of first and second internal electrodes 121 and 122 may be stacked alternately in the Z-direction of the body 110 and exposed on the first and second surfaces of the body 110, respectively. Since the first and second bonding layers 151 and 152 may exist as thin films, they can consequently be connected to the first and second external electrodes 131 and 132, respectively. That is, capacitance can be realized. However, this is only one example, and the plurality of first and second internal electrodes 121 and 122 may be arranged in other forms. For example, the plurality of first and second internal electrodes 121 and 122 may be stacked alternately in the Y-direction of the body 110 and exposed on the first and second surfaces of the body 110, respectively, but are not limited to this.

[0024] The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132. The first and second external electrodes 131 and 132 can be positioned on the first and second bonding layers 151 and 152, respectively, at both ends of the main body 110 in the X-direction. For example, the first external electrode 131 may be positioned on the first surface of the main body 110, with portions extending onto the third to sixth surfaces of the main body 110. The second external electrode 132 may be positioned on the second surface of the main body 110, with portions extending onto the third to sixth surfaces of the main body 110.

[0025] However, this is merely one example, and the first and second external electrodes 131 and 132 can also be arranged in other configurations. For example, the first external electrode 131 may be positioned on the first surface of the main body 110, with portions extending only onto the fifth and / or sixth surfaces of the main body 110. Similarly, the second external electrode 132 may be positioned on the second surface of the main body 110, with portions extending only onto the fifth and / or sixth surfaces of the main body 110. In addition, the first and second external electrodes 131 and 132 can be arranged in a variety of other configurations.

[0026] The thickness of the external electrodes 131 and 132 can be made substantially constant. Here, substantially constant thickness means that the thickness is substantially the same at any point, and this includes not only cases where it is completely the same, but also cases where it is almost the same, so this can be determined by taking into account process errors, positional deviations, and measurement errors that occur during the manufacturing process. This can be achieved by separately manufacturing and firing the external electrodes 131 and 132.

[0027] For example, after injecting a paste to form the external electrodes into a casting mold and shaping it, the external electrodes 131 and 132 can be formed by independently firing the mold. Subsequently, bonding layers 151 and 152 can be coated onto the separately manufactured external electrodes 131 and 132. After this, the external electrodes 131 and 132 can be joined to the main body 110 by heat treatment at a temperature of approximately 400°C to 500°C using the bonding layers 151 and 152 as an interface. Therefore, the thickness of the external electrodes 131 and 132 on the main body 110 can be substantially constant. Alternatively, if necessary, the bonding layers 151 and 152 can be coated onto the outer surface of the main body 110, and then the heat treatment bonding described above can be performed. In this way, the external electrodes 131 and 132 can be fired separately to achieve the desired shape, and the completed external electrodes 131 and 132 can be assembled onto the main body 110. Therefore, even when achieving a substantially constant thickness, the method does not need to be constrained by the fluid dynamics properties of the binder. Furthermore, by lowering the heat treatment temperature by approximately 200°C to 350°C compared to conventional methods, the risk of radial cracking associated with the increased number of layers in high-capacity models can be eliminated. In addition, unlike conventional methods, density is almost fully achieved, thus reducing the temperature dependence of capacity realization.

[0028] From this perspective, in cross-sections in the X and Z directions, the thickness ta1 of the first external electrode 131 at the center of the first surface of the main body 110 can be substantially the same as the thickness ta2 at the edge of the first surface of the main body 110. For example, ta1 / ta2 can be approximately 0.9 to 1.1 or 0.95 to 1.05. Furthermore, the thickness tb1 of the second external electrode 132 at the center of the second surface of the main body 110 can be substantially the same as the thickness tb2 at the edge of the second surface of the main body 110. For example, tb1 / tb2 can be approximately 0.9 to 1.1 or 0.95 to 1.05. This can be roughly measured using SEM images in cross-sections in the X and Z directions.

[0029] From this perspective, in cross-sections in the X and Z directions, the thickness ta1 of the first external electrode 131 at the center of the first surface of the main body 110 can be substantially the same as the thickness ta3 at the corner where the first surface of the main body 110 is connected to the fifth or sixth surface. For example, ta1 / ta3 can be approximately 0.9 to 1.1 or 0.95 to 1.05. Similarly, the thickness tb1 of the second external electrode 132 at the center of the second surface of the main body 110 can be substantially the same as the thickness tb3 at the corner where the second surface of the main body 110 is connected to the fifth or sixth surface. For example, tb1 / tb3 can be approximately 0.9 to 1.1 or 0.95 to 1.05. This can be roughly measured using SEM images in cross-sections in the X and Z directions.

[0030] Here, the meaning of "cross-section in the X-direction and Z-direction" can refer to the cross-sectional shape when the object is cut perpendicularly in the X-direction and Z-direction, or to the cross-sectional shape when the object is viewed from the side in the X-direction and Z-direction.

[0031] The external electrodes 131 and 132 may contain a conductor, which may include copper (Cu), nickel (Ni), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), lead (Pb), and / or alloys containing these. The external electrodes 131 and 132 can be formed using a paste containing such a conductor, preferably copper (Cu), in the manner described above. On the other hand, after the paste is poured into the casting mold, it is preferable to minimize the amount of solvent and organic matter contained in the paste in order to introduce shrinkage changes as much as possible during the drying and firing processes, and to suppress side effects due to organic matter decomposition. Furthermore, after the formation of the thin film coating layer, an interface containing silica and / or low-melting-point glass is formed at the interface between the external electrodes 131 and 132 and the main body 110 via heat treatment bonding, so the glass content can be as small as possible relative to the copper (Cu).

[0032] If necessary, additional plating layers including a nickel layer, a tin layer, or a combination thereof can be placed on the external electrodes 131 and 132. For example, a nickel layer and a tin layer can be sequentially placed on the first and second external electrodes 131 and 132, respectively. The plating layers can be formed by known plating processes such as electroplating and electroless plating, and the specific plating method is not particularly limited.

[0033] The bonding layers 151 and 152 may include a first bonding layer 151 and a second bonding layer 152. The first and second bonding layers 151 and 152 can be positioned at both ends of the main body 110 in the X-direction, respectively. For example, the first bonding layer 151 can be positioned between the first surface of the main body 110 and the first external electrode 131, with a portion of it extending between the third to sixth surfaces of the main body 110 and the first external electrode 131. The second bonding layer 152 can be positioned between the second surface of the main body 110 and the second external electrode 132, with a portion of it extending between the third to sixth surfaces of the main body 110 and the second external electrode 132.

[0034] However, this is merely one example, and the first and second bonding layers 151 and 152 can be arranged in other configurations. For example, the first bonding layer 151 can be positioned between the first surface of the main body 110 and the first external electrode 131, with a portion of each extending only between the fifth and / or sixth surfaces of the main body 110 and the first external electrode 131. Similarly, the second bonding layer 152 can be positioned between the second surface of the main body 110 and the second external electrode 132, with a portion of each extending only between the fifth and / or sixth surfaces of the main body 110 and the second external electrode 132. In addition, the first and second bonding layers 151 and 152 can be arranged in a variety of other configurations.

[0035] The bonding layers 151 and 152 can be directly positioned on at least one surface of the main body 110. For example, the first bonding layer 151 can be directly positioned on the first surface of the main body 110, and a portion of it can be directly extended to at least one of the third to sixth surfaces of the main body 110. Similarly, the second bonding layer 152 can be directly positioned on the second surface of the main body 110, and a portion of it can be directly extended to at least one of the third to sixth surfaces of the main body 110. Here, when a bonding layer is directly positioned on a surface of the main body, it can be said that there is no other separate configuration between the bonding layer and that surface of the main body.

[0036] The bonding layers 151 and 152 can be thinner than the external electrodes 131 and 132. For example, the first bonding layer 151 can be thinner than the first external electrode 131. Also, the second bonding layer 152 can be thinner than the second external electrode 132. Here, the thickness can be roughly determined using SEM images on the cross-section in the X-direction and Z-direction. From this viewpoint, the bonding layers 151 and 152 can be formed in the form of a thin film coating layer before heat treatment bonding. The coating thickness can be controlled by the concentration of the solution, and it is preferable to coat it as thinly as possible in order to achieve capacity. For example, the thickness of the coating layer can be about 1 μm or less, or about 800 nm or less, for example, about 400 nm to 600 nm, but is not limited to this. With such thin film formation, the external electrodes 131 and 132 can be connected to the internal electrodes 121 and 122 after heat treatment bonding to achieve capacity.

[0037] From this perspective, the bonding layers 151 and 152 can exist as interfaces between the external electrodes 131 and 132 after heat treatment bonding and the main body 110. For example, the first bonding layer 151 can exist as an interface between the main body 110 and the first external electrode 131. Similarly, the second bonding layer 152 can exist as an interface between the main body 110 and the second external electrode 132. In particular, the boundaries formed by the bonding layers 151 and 152 can be more clearly observed in the band region, for example, on the third to sixth surfaces of the main body 110.

[0038] The bonding layers 151 and 152 may contain silica (SiO2). For example, the bonding layers 151 and 152 can be formed by coating the inside of external electrodes 131 and 132, which are manufactured separately using a paste containing perhydro-polysilazane (SiH2NH), or by coating the outside of the main body 110, and then undergoing a heat treatment bonding process. The coating method is not particularly limited. Alternatively, the bonding layers 151 and 152 may contain low-melting-point glass. For example, the bonding layers 151 and 152 can be formed by coating the inside of external electrodes 131 and 132, which are manufactured separately using a paste containing low-melting-point glass, or by coating the outside of the main body 110, and then undergoing a heat treatment bonding process. The coating method is not particularly limited. Here, the low-melting-point glass can be glass with a melting point of 500°C or less, for example, a melting point of about 350°C to 450°C, and may contain various other types of glass in addition to the silica mentioned above.

[0039] Figure 3 is a schematic perspective view of a ceramic electronic component according to another example, and Figure 4 is a schematic cross-sectional view of the ceramic electronic component of Figure 3 cut along the line II-II'.

[0040] Referring to the drawings, another example of the ceramic electronic component 100B may have external electrodes 131 and 132 in the form of copper sheets having substantially constant thickness. For example, bonding layers 151 and 152 may be placed only on the first and second surfaces of the main body 110, and external electrodes 131 and 132 may be placed on the bonding layers 151 and 152 only on the first and second surfaces of the main body 110.

[0041] External electrodes 131 and 132 can be formed by a copper sheet transfer method. For example, after preparing fully fired copper sheets as external electrodes 131 and 132, a coating layer containing silica and / or low-melting-point glass can be formed on one surface of the copper sheets to form bonding layers 151 and 152. Then, the external electrodes 131 and 132 can be formed by heat treatment bonding to the main body 110 using the bonding layers 151 and 152 as the interface. If necessary, a coating layer can be formed on the outer surface of the main body 110, and then heat treatment bonding of separately manufactured external electrodes can be performed.

[0042] Other details, such as those described for ceramic electronic component 100A above, can also be applied to ceramic electronic component 100B using other examples, as long as they do not contradict each other, and explanations of the overlapping content will be omitted.

[0043] Figure 5 is a schematic perspective view of a ceramic electronic component according to another example, and Figure 6 is a schematic cross-sectional view of the ceramic electronic component of Figure 5 cut along the line III-III'.

[0044] Referring to the drawings, in another example, the ceramic electronic component 100C may have external electrodes 131 and 132 in the form of nickel sheets having substantially constant thickness. For example, bonding layers 151 and 152 may be placed only on the first and second surfaces of the body 110, and the external electrodes 131 and 132 may be placed on the bonding layers 151 and 152 only on the first and second surfaces of the body 110.

[0045] The external electrodes 131 and 132 can be formed by a nickel sheet transfer method. For example, after preparing a fully calcined nickel sheet as the external electrodes 131 and 132, a coating layer containing silica and / or low-melting-point glass can be formed on one surface of the nickel sheet to form bonding layers 151 and 152. The external electrodes 131 and 132 can then be formed by heat treatment bonding to the main body 110 using the bonding layers 151 and 152 as the interface. If necessary, a coating layer can be formed on the outer surface of the main body 110, and then heat treatment bonding of separately manufactured external electrodes can be performed.

[0046] Other details, such as those described above for ceramic electronic component 100A, can also be applied to ceramic electronic component 100C using other examples, provided they do not contradict each other, and explanations of the overlapping content will be omitted.

[0047] Figure 7 is a schematic perspective view of a ceramic electronic component according to another example, and Figure 8 is a schematic cross-sectional view of the ceramic electronic component of Figure 7 cut along the line IV-IV'.

[0048] Referring to the drawings, another example of the ceramic electronic component 100D is that the external electrodes 131, 132 may include multiple electrode layers 131a, 131b, 132a, 132b. For example, the first external electrode 131 may include a first electrode layer 131a disposed on the first surface of the body 110, and a second electrode layer 131b disposed on the first surface of the body 110, covering the first electrode layer 131a, and partially extending onto the third to sixth surfaces of the body 110. The second external electrode 132 may include a third electrode layer 132a disposed on the second surface of the body 110, and a fourth electrode layer 132b disposed on the second surface of the body 110, covering the third electrode layer 132a, and partially extending onto the third to sixth surfaces of the body 110. The first bonding layer 151 may be disposed between the first surface of the body 110 and the first and second electrode layers 131a, 131b, respectively. The second bonding layer 152 can be positioned between the second surface of the main body 110 and the third and fourth electrode layers 132a and 132b, respectively. The first and third electrode layers 131a and 132a may each contain nickel (Ni), and the second and fourth electrode layers 131b and 132b may each contain copper (Cu).

[0049] For example, after pre-bonding a nickel sheet to a casting frame, copper paste can be injected and dried and fired to form the external electrodes 131 and 132. Then, bonding layers 151 and 152 can be coated onto at least a portion of the separately manufactured external electrodes 131 and 132, and the external electrodes 131 and 132 can be bonded to the main body 110 by heat bonding using the bonding layers 151 and 152 as an interface. If necessary, a coating layer can be formed on the outer surface of the main body 110 before heat bonding of the separately manufactured external electrodes. Alternatively, a coating layer can be formed on the outer surface of the main body 110, and then the nickel sheet and copper electrodes can be formed by heat bonding.

[0050] Other details, such as those described for ceramic electronic component 100A above, can also be applied to ceramic electronic component 100D using other examples, provided they do not contradict each other, and explanations of the overlapping content will be omitted.

[0051] Figure 9 is a schematic cross-sectional view showing an example of a silica coating layer being formed on a copper electrode.

[0052] Referring to the drawings, the silica coating layer can be formed by applying a paste containing perhydro-polysilazane (SiH2NH) onto the copper electrode. Perhydro-polysilazane (SiH2NH) reacts with moisture in the atmosphere to form the silica coating layer. The silica coating layer can be a layer of linked silica and can be in the form of a thin film. The silica coating layer can be used as a bonding layer in the heat treatment bonding of the copper electrode. The silica coating layer can exist as the interface between the copper electrode and the ceramic body after the heat treatment bonding.

[0053] Figure 10 is a schematic cross-sectional SEM (Scanning Electron Microscope) image showing the formation of a bonding layer at the interface between the main body and the external electrode.

[0054] Referring to the drawings, it can be seen that when the main body 110, for example, an external electrode 131, for example, a copper (Cu) electrode, which is separately fired onto the dielectric layer, is heat-treated and bonded using a bonding layer 151, for example, a silica and / or low-melting-point glass coating layer, the bonding layer 151 can exist between the main body 110 and the external electrode 131 in the form of a thin film. In other words, it can be seen that the bonding layer 151 containing glass can exist as an interface. This is even clearer when the heat treatment temperature is low, around 400°C.

[0055] On the other hand, as the heat treatment temperature increases, the glass in the bonding layer 151 can gradually migrate to the external electrode 131. Therefore, the boundary may become increasingly blurred. In this case, glass may not be distributed in the surface area of ​​the external electrode 131.

[0056] Figure 11 is a schematic cross-sectional SEM image showing the distribution of copper and glass within the external electrode when the bonding layer is not included.

[0057] Referring to the drawings, when an external electrode without a bonding layer is fired together with a ceramic body that has an external electrode in the form of a copper electrode formed by dipping, it is necessary to ensure a sufficient content of glass frit or similar material in the paste used to form the external electrode in order to secure bonding strength with the ceramic body. Therefore, it can be seen that after firing, glass occupies a considerable area not only in the interface region with the ceramic body of the external electrode but also in the surface region.

[0058] More specifically, as an example, if, in a cross-section in the X-direction and Z-direction, the area from the inner surface of the external electrode connected to the ceramic body to the 7 μm thickness point of the external electrode is defined as the interface region, and the area from the 7 μm thickness point of the external electrode to the outer surface of the external electrode is defined as the surface region, then, in terms of area ratio on the cross-sectional SEM after firing, the area ratio of glass to copper in the interface region can be, for example, about 38.4%, and the area ratio of glass to copper in the surface region can be, for example, about 42.7%. The glass composition of the external electrode can be measured using an SEM (Scanning Electron Microscope)-EDS (Energy Dispersive Spectrometer) equipped under conditions such as an acceleration voltage of 10 kV and a WD of 10 mm.

[0059] Thus, in cross-sections in the X- and Z-directions, the area ratio of glass to copper in the surface region of the external electrode after firing can actually be larger than the area ratio of glass to copper in the interface region of the external electrode. For example, if the area ratio in the interface region is Sa and the area ratio in the surface region is Sb, then Sb / Sa × 100% can be approximately 70% to 120%, but is not limited to this.

[0060] Figures 12 and 13 are schematic cross-sectional SEM images showing the distribution of copper and glass within the external electrode when a bonding layer is included.

[0061] Referring to the drawings, when an external electrode includes a bonding layer, for example, when an external electrode is manufactured separately and fired as in this disclosure, and then heat-treated and bonded to a ceramic body using a silica coating layer or a low-melting-point glass coating layer, the content of glass frit and the like in the paste for forming the external electrode can be minimized, thereby reducing the area ratio of glass to copper on the surface region of the external electrode after firing.

[0062] More specifically, as a few examples, if, on a cross-section in the X-direction and Z-direction, the interface region is defined as the area from the inner surface of the external electrode connected to the ceramic body to the 7 μm thickness point of the external electrode, and the surface region is defined as the area from the 7 μm thickness point to the outer surface of the external electrode, then, in terms of area ratio on the cross-sectional SEM after firing, the area ratio of glass to copper in the interface region can be, for example, 10% to 20%, more specifically 10.8% or 17.3%, and the area ratio of glass to copper in the surface region can be, for example, 3% to 5%, more specifically 3.5% or 3.8%. The glass composition of the external electrode can be measured with SEM-EDS equipped under conditions such as an acceleration voltage of 10 kV and a WD of 10 mm.

[0063] Thus, in cross-sections in the X- and Z-directions, the area ratio of glass to copper in the surface region of the external electrode after firing can be even smaller than the area ratio of glass to copper in the interface region of the external electrode. For example, if the area ratio in the interface region is Sa and the area ratio in the surface region is Sb, then Sb / Sa × 100% can be approximately 0.01% to 35%, but is not limited to this. For example, if the heat treatment temperature is increased to a high temperature similar to conventional methods, Sb can be close to 0.

[0064] Experimental example A 0402-size ceramic laminate was prepared as an experimental sample by stacking dielectric sheets made of barium titanate-based dielectric material and dielectric sheets on which a conductive paste containing nickel (Ni) was printed, and then bonding them together through processes such as compression.

[0065] In the experimental examples 1-8 shown in [Table 1] below, a copper (Cu) paste was applied to the prepared ceramic laminate using a dipping method, and then the external electrodes were formed by firing and bonding at various bonding temperatures as described below.

[0066] Furthermore, in experimental examples 9-16 in [Table 1] below, a copper (Cu) paste was injected into a casting mold and molded, then this was independently fired to form the external electrode. After that, a thin silica coating layer was formed on the external electrode, and then the external electrode was formed by heat treatment bonding at various bonding temperatures as described below to the prepared ceramic laminate.

[0067] Subsequently, the volume, radial cracks, and C / C ratio of the manufactured MLCC sample chips were measured and are shown in [Table 1] below. Here, based on 10,000 sample chips under the same repeating conditions, △ indicates that less than 60% were good, ○ indicates that approximately 60-90% were good, and ◎ indicates that approximately 90-100% were good.

[0068] On the other hand, capacity refers to the percentage of the product that meets the standard capacity specifications for each model. For example, a product was judged to be good quality if its capacity was measured using an LCR meter two hours after heat treatment and fell within the specified capacity range (unit: uF).

[0069] Furthermore, to detect radial cracks, each sample chip was placed horizontally, fixed around the chip with epoxy resin, and polished with a polishing machine to expose the cross-sections in the X and Y directions. Polishing was then performed in the Z direction to a depth of approximately 1 / 4, and after polishing to the margin, the frequency of crack occurrence at the edge of the ceramic laminate was measured using SEM-EDS.

[0070] The C / C ratio refers to the ratio of the center thickness to the corner thickness of the external electrode. Each sample tip was placed horizontally, fixed around the tip with epoxy resin, and polished with a polishing machine to expose the cross-sections in the X and Y directions. After polishing to a depth of approximately 1 / 2 in the Z direction, the thickness at each point was measured using SEM-EDS equipment and the ratio was calculated.

[0071] [Table 1]

[0072] As can be seen from [Table 1], in experimental examples 1-8, there is a problem of insufficient capacitance when the bonding temperature is low, and a problem of radial cracking when the bonding temperature is high. In addition, it can be seen that the C / C ratio is 0.5 or less, and the thickness of the external electrode is not uniform.

[0073] On the other hand, in experimental examples 9-16, it can be seen that there are almost no problems with capacity and radial cracking regardless of the heat treatment temperature. In other words, since the external electrode is already fired, the diffusion coefficient for diffusion to the internal electrode is extremely low, and radial cracking may not occur even at high temperatures. Furthermore, in all cases, it can be seen that the closer the C / C ratio is to approximately 1, the more uniform the thickness of the external electrode can be formed.

[0074] In this disclosure, for convenience, terms such as "side" and "side" are used to mean the left / right direction or the surface in that direction relative to the drawing; for convenience, terms such as "up" and "top" are used to mean the upward direction or the surface in that direction relative to the drawing; and for convenience, terms such as "down" and "bottom" are used to mean the downward direction or the surface in that direction. Furthermore, the terms "side," "up," "top," "down," or "bottom" are used to include not only cases where the component in question is in direct contact with the reference component in the relevant direction, but also cases where it is located in the relevant direction but does not directly contact it. However, this is a definition of direction for explanatory purposes only, and the scope of the claims is not particularly limited by such descriptions of direction, and concepts such as "up" and "down" can change at any time.

[0075] In this disclosure, "connected" includes not only direct connection but also indirect connection via an adhesive layer or the like. Furthermore, "electrically connected" includes both physically connected and non-connected cases. The terms "first," "second," etc., are used to distinguish one component from another and do not limit the order and / or importance of the components. In some cases, without exceeding the scope of the rights, the first component may be named the second component, and similarly, the second component may be named the first component.

[0076] The expression "example" as used in this disclosure does not mean that each embodiment is identical to another, but is provided to highlight and illustrate the unique and distinct features of each. However, the examples presented above do not preclude their implementation in combination with features of other examples. For example, even if a matter described in one example is not described in another example, it can be understood as a description related to the other example, unless there is a description in the other example that contradicts or is inconsistent with that description.

[0077] The terms used in this disclosure are for illustrative purposes only and are not intended to limit the disclosure. Where otherwise, singular expressions include plural expressions unless the context clearly indicates otherwise.

Claims

1. A main body including a dielectric layer and internal electrodes, The body includes an external electrode disposed on the main body, The external electrode comprises copper and glass. In the cross-section in the length and thickness directions, A ceramic electronic component in which, when the area from the inner surface of the external electrode to the point where the external electrode is 7 μm thick is defined as the first region, and the area from the point where the external electrode is 7 μm thick to the outer surface of the external electrode is defined as the second region, the area ratio of the glass to the copper in the second region is even smaller than the area ratio of the glass to the copper in the first region.

2. The system further includes a bonding layer disposed between the main body and the external electrode, The ceramic electronic component according to claim 1, wherein the thickness of the external electrode is substantially constant.

3. The ceramic electronic component according to claim 2, wherein the bonding layer is thinner than the external electrode.

4. The aforementioned bonding layer is silica (SiO ２ A ceramic electronic component according to claim 2, including ).

5. The bonding layer includes low-melting-point glass. The low-melting-point glass has a melting point of 500°C or less, as described in claim 2, for the ceramic electronic component.

6. The ceramic electronic component according to claim 1, wherein the area ratio of the glass to the copper in the first region is 10% to 20%.

7. The ceramic electronic component according to claim 1, wherein the area ratio of the glass to the copper in the second region is 3% to 5%.

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