Multilayer ceramic electronic component

Abstract

The present disclosure provides a multilayer ceramic electronic component. The multilayer ceramic electronic component includes a ceramic main body including dielectric layers and first and second internal electrodes; a first external electrode including a first base electrode disposed in contact with the ceramic main body and a first conductive layer disposed on the first base electrode; and a second external electrode including a second base electrode disposed in contact with the ceramic main body and a second conductive layer disposed on the second base electrode, wherein the first and second conductive layers include silver (Ag) and palladium (Pd), and the distribution positions of silver (Ag) and palladium (Pd) in central portions of the first and second conductive layers match 95% or more according to the results of TEM mapping.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0189785, filed on December 31, 2020, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to a multilayer ceramic electronic component. Background Technology

[0003] In recent years, with the expansion of the application fields of electronic products, the technological field of using multilayer ceramic electronic components has also expanded. In particular, with the electrification of vehicles, electronic control units (ECUs) or transmission control units (TCUs) are used, with the ECUs located in the engine compartment or directly attached to the transmission.

[0004] However, when existing multilayer ceramic electronic components are applied to harsh environments such as high temperatures and high vibrations, repeated expansion and contraction due to high / low temperature cycling causes continuous mechanical stress. Furthermore, the application of continuous mechanical stress is a major cause of cracking in terminal electrodes or solder.

[0005] To address this issue, methods have been proposed using conductive adhesives other than solder. Conductive adhesives used in vehicle electrical equipment are typically applied by mixing a conductive metal with a base resin such as epoxy resin. The use of conductive adhesives can mitigate cracking caused by mechanical stress because the base resin has a higher elastic modulus than the solder.

[0006] However, despite the use of conductive adhesives, repeated exposure to high temperature / high humidity environments increases the likelihood of ion migration in the external electrodes of multilayer ceramic electronic components. This ion migration is a major cause of reliability degradation in multilayer ceramic electronic components. Furthermore, using noble metals such as palladium (Pd) to suppress ion migration could be prohibitively expensive. Summary of the Invention

[0007] One aspect of this disclosure is to provide a multilayer ceramic electronic component capable of suppressing ion migration.

[0008] One aspect of this disclosure also provides a multilayer ceramic electronic component that has improved economic efficiency by reducing the use of precious metals.

[0009] One aspect of this disclosure also provides a multilayer ceramic electronic component with excellent reliability.

[0010] According to one aspect of this disclosure, a multilayer ceramic electronic component includes: a ceramic body including a dielectric layer and alternatingly stacked first and second inner electrodes, wherein the dielectric layer is located between the first and second inner electrodes; a first outer electrode connected to the first inner electrode and including a first base electrode and a first conductive layer, wherein the first base electrode is disposed in contact with the ceramic body and the first conductive layer is disposed on the first base electrode; and a second outer electrode connected to the second inner electrode and including a second base electrode and a second conductive layer, wherein the second base electrode is disposed in contact with the ceramic body and the second conductive layer is disposed on the second base electrode, wherein the first and second conductive layers include silver (Ag) and palladium (Pd), and according to TEM mapping results, the distribution positions of silver (Ag) and palladium (Pd) in the central portions of the first and second conductive layers are matched at 95% or higher.

[0011] According to another aspect of this disclosure, a multilayer ceramic electronic component includes: a ceramic body having a first side surface and a second side surface opposite to each other in a length direction; a first external electrode and a second external electrode, respectively disposed on the first side surface and the second side surface, each of the first external electrode and the second external electrode including a base electrode layer disposed on the respective side surface and a conductive layer disposed on the base electrode layer, the conductive layer comprising an Ag-Pd alloy having an average alloying rate of more than 95%, wherein the alloying rate is defined as a ratio B / A, where B is the weight of the Ag-Pd alloy and A is the sum of the total weight of Ag and the total weight of Pd. Attached Figure Description

[0012] The above and other aspects, features and advantages of this disclosure will be more clearly understood by taking into account the accompanying drawings and the following detailed description, in which:

[0013] Figure 1 This is a schematic perspective view of a multilayer ceramic electronic assembly according to exemplary embodiments of the present disclosure;

[0014] Figure 2 It is shown schematically. Figure 1 A three-dimensional view of the ceramic body;

[0015] Figure 3 It is along Figure 1 A cross-sectional view taken from line I-I';

[0016] Figure 4 yes Figure 3 A magnified view of region A;

[0017] Figure 5It is a SEM image of a cross-section of a multilayer ceramic electronic assembly according to exemplary embodiments of the present disclosure;

[0018] Figure 6 This is a transmission electron microscope (TEM) image of a cross-section of a multilayer ceramic electronic component according to exemplary embodiments of the present disclosure;

[0019] Figure 7 It is relative to Figure 6 The image shows the energy dispersive spectral (EDS) mapping images of palladium (Pd) and silver (Ag);

[0020] Figure 8 This is a TEM image of a cross-section of a multilayer ceramic electronic component according to another exemplary embodiment of this disclosure;

[0021] Figure 9 It is relative to Figure 8 EDS-mapped images of palladium (Pd) and silver (Ag);

[0022] Figure 10 These are EDS mapping images of palladium (Pd) and silver (Ag);

[0023] Figure 11 This is a TEM image of a cross-section of a multilayer ceramic electronic component according to a comparative example of this disclosure;

[0024] Figure 12 It is relative to Figure 11 EDS-mapped images of palladium (Pd) and silver (Ag);

[0025] Figure 13 This is a TEM image of a cross-section of a multilayer ceramic electronic component according to a comparative example of this disclosure;

[0026] Figure 14 It is relative to Figure 13 EDS-mapped images of palladium (Pd) and silver (Ag);

[0027] Figure 15 These are captured images showing ion migration test results according to examples and comparative examples of this disclosure; and

[0028] Figure 16 It is an image of a crack that appears in a component of existing technology. Detailed Implementation

[0029] Exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. For clarity, the shapes and dimensions of the constituent elements in the drawings may be exaggerated or reduced. In the drawings, variations in the illustrated shapes may be estimated, for example, due to manufacturing techniques and / or tolerances. Therefore, embodiments of the present disclosure should not be construed as limited to specific shapes in the areas shown herein, including, for example, changes in shape caused during manufacturing. The following embodiments may also be constituted by one or a combination thereof.

[0030] However, this disclosure may be exemplified in many different forms and should not be construed as being limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0031] It will be readily understood that although terms such as first, second, and third may be used herein to describe various components, assemblies, regions, layers, and / or parts, these components, assemblies, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the exemplary embodiments, the first component, first assembly, first region, first layer, or first part mentioned below may be referred to as a second component, second assembly, second region, second layer, or second part.

[0032] For ease of description, spatial relative terms such as “above,” “above,” “below,” and “under” are used herein to describe the relationship between one element and another as shown in the accompanying drawings. It will be understood that spatial relative terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, the element described as “above” or “above” other elements or features will then be located “below” or “under” those other elements or features. Thus, the term “above” may include both “above” and “below” orientations depending on the specific orientation of the drawings. The device may be otherwise positioned (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0033] The terminology used herein describes specific embodiments only, and this disclosure is not limited thereto. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It will be further understood that when the terms “comprising” and / or “including” are used in this specification, the presence of the stated features, integrals, steps, operations, components, elements, and / or groups thereof is specified, but the presence or addition of one or more other features, integrals, steps, operations, components, elements, and / or groups thereof is not excluded.

[0034] The contents of this disclosure described below may have various configurations, and only the required configurations are presented herein, but are not limited thereto.

[0035] In the accompanying drawings, the X direction can be defined as a first direction, the L direction, or the length direction; the Y direction can be defined as a second direction, the W direction, or the width direction; and the Z direction can be defined as a third direction, the T direction, or the thickness direction.

[0036] Figure 1 This is a schematic perspective view of a multilayer ceramic electronic assembly according to exemplary embodiments of the present disclosure. Figure 2 This is a schematic three-dimensional view showing the ceramic body of a multilayer ceramic electronic component. Figure 3 It is along Figure 1 A cross-sectional view taken from line I-I'. Figure 4 yes Figure 3 A magnified view of region A.

[0037] In the following text, reference will be made to Figures 1 to 4 A detailed description of a multilayer ceramic electronic component according to an exemplary embodiment.

[0038] Reference Figures 1 to 4 A multilayer ceramic electronic assembly 100 according to exemplary embodiments of the present disclosure includes: a ceramic body 110 including a dielectric layer 111 and alternatingly stacked first inner electrode 121 and second inner electrode 122, wherein the dielectric layer 111 is disposed between the first inner electrode 121 and the second inner electrode 122; a first outer electrode 131 connected to the first inner electrode 121 and including a first base electrode 131a and a first conductive layer 131b, wherein the first base electrode 131a is disposed in contact with the ceramic body 110 and the first conductive layer 131b is disposed on the first base electrode 131a; and a second outer electrode 132 connected to the second inner electrode 122 and including a second base electrode 132a and a second conductive layer 132b, wherein the second base electrode 132a is disposed in contact with the ceramic body 110 and the second conductive layer 132b is disposed on the second base electrode 132a. The ceramic body 110 may include a first surface S1 and a second surface S2 that are opposite to each other in the X direction, a third surface S3 and a fourth surface S4 that are opposite to each other in the Y direction, and a fifth surface S5 and a sixth surface S6 that are opposite to each other in the Z direction.

[0039] Here, the first conductive layer 131b and the second conductive layer 132b include silver (Ag) and palladium (Pd), and according to the results of TEM mapping, the distribution positions of silver (Ag) and palladium (Pd) in the central portion of the first conductive layer 131b and the second conductive layer 132b can match 95% or higher.

[0040] In this disclosure, when the average thickness of the first conductive layer 131b and / or the second conductive layer 132b in the first direction (X direction) is T, the "central portion" of the first conductive layer 131b and the second conductive layer 132b may refer to the portion with a thickness of 1 / 2 × T. (Refer to...) Figure 4 The central portion of the first conductive layer 131b and the second conductive layer 132b can be a location where the first conductive layer 131b and / or the second conductive layer 132b have been ground to a thickness t in the first direction (X direction). Here, t = 1 / 2 × T. Furthermore, the central portion can refer to a region with a square shape of 50 μm × 50 μm based on the central axis C of the multilayer ceramic electronic assembly 100 in the first direction (X direction) according to this disclosure. That is, the center of the 50 μm × 50 μm region can be matched with the central axis C of the multilayer ceramic electronic assembly 100 in the first direction (X direction).

[0041] In the multilayer ceramic electronic assembly according to this disclosure, the distribution locations of silver (Ag) and palladium (Pd) can be matched with 95% or higher based on the results of TEM mapping in the central portions of the first conductive layer 131b and the second conductive layer 132b. The distribution locations of silver (Ag) and palladium (Pd) can be determined by analyzing the distribution locations of silver (Ag) and palladium (Pd) using an image analysis program (e.g., Mediacybernetics' Image Pro Plus version 4.5) after imaging the central portions of the first conductive layer 131b and / or the second conductive layer 132b with a transmission electron microscope (TEM).

[0042] The distribution positions of silver (Ag) and palladium (Pd) in the central portions of the first conductive layer 131b and the second conductive layer 132b can be matched at 95% or higher, 96% or higher, 97% or higher, 98% or higher, or 99% or higher, with no particular upper limit, but can be, for example, 100% or lower. The matching of the distribution positions of silver (Ag) and palladium (Pd) in the central portions of the first conductive layer 131b and the second conductive layer 132b indicates that silver (Ag) and palladium (Pd) do not exist separately as individual components, but are jointly disposed within the conductive layer as a single component. That is, the overlap of the distribution positions of silver (Ag) and palladium (Pd) can mean that silver (Ag) and palladium (Pd) exist as an alloy phase. In the multilayer ceramic electronic assembly according to this disclosure, the overlap ratio of the distribution ranges of silver (Ag) and palladium (Pd) in the central portions of the first conductive layer 131b and the second conductive layer 132b satisfies the above range, thereby effectively suppressing ion migration of the external electrode.

[0043] A multilayer ceramic electronic component 100 according to an exemplary embodiment of the present disclosure may include a dielectric layer 111 and alternatingly stacked first inner electrode 121 and second inner electrode 122, wherein the dielectric layer 111 is disposed between the first inner electrode 121 and the second inner electrode 122.

[0044] According to the present disclosure, the ceramic body 110 of the multilayer ceramic electronic component 100 may include a dielectric layer 111 and a first internal electrode 121 and a second internal electrode 122 stacked in a third direction (Z direction), and the dielectric layer 111 is located between the first internal electrode 121 and the second internal electrode 122.

[0045] There are no particular limitations on the specific shape of the ceramic body 110, but as shown in the figure, the ceramic body 110 may have a hexahedral shape or a similar shape. Due to the shrinkage of the ceramic powder contained in the ceramic body 110 during the sintering process, the ceramic body 110 may have a generally hexahedral shape, but it is not a hexahedral shape with perfectly straight lines. If desired, the ceramic body 110 may be rounded so that the corners are not angled. The rounding process may be, for example, tumbling, but is not limited to this.

[0046] In the ceramic body 110, dielectric layers 111, first internal electrodes 121, and second internal electrodes 122 can be stacked alternately. Dielectric layers 111, first internal electrodes 121, and second internal electrodes 122 can be stacked in the third direction (Z direction). Multiple dielectric layers 111 are in a sintered state, and adjacent dielectric layers 111 can become a single unit, making their boundaries difficult to distinguish without the use of a scanning electron microscope (SEM).

[0047] According to exemplary embodiments in this disclosure, dielectric layer 111 may include dielectric layers composed of (Ba 1-x Ca x (Ti) 1-y (Zr,Sn,Hf) y The component is represented by BaTiO3 (here, 0 ≤ x ≤ 1 and 0 ≤ y ≤ 0.5). The component can be, for example, a compound in which Ca, Zr, Sn, and / or Hf are partially dissolved in BaTiO3. In the above compositional formula, x can be in the range greater than or equal to 0 and less than or equal to 1, and y can be in the range greater than or equal to 0 and less than or equal to 0.5, but is not limited thereto. For example, when x is 0 and y is 0, the component in the above compositional formula can be BaTiO3. Furthermore, according to the purposes of this disclosure, various ceramic additives, organic solvents, plasticizers, binders, dispersants, etc., can be added to the component.

[0048] The dielectric layer 111 can be formed by adding necessary additives to a slurry containing the above-described materials, coating the slurry onto a carrier film, and drying the slurry to prepare multiple ceramic sheets. The ceramic sheets can be formed by using a doctor blade to form sheets with a thickness of several micrometers, but are not limited to this method.

[0049] The ceramic body 110 can be formed by alternately stacking ceramic green sheets in the third direction (Z direction) wherein a first inner electrode 121 is printed on a dielectric layer 111 and a second inner electrode 122 is printed on a dielectric layer 111. The printing method for the first inner electrode and the second inner electrode can be screen printing or gravure printing, but is not limited to these methods.

[0050] The first inner electrode 121 and the second inner electrode 122 may be stacked such that they are exposed at opposite ends of the ceramic body 110. Specifically, the first inner electrode 121 and the second inner electrode 122 may be exposed on two surfaces of the ceramic body 110 in a first direction (X direction), and in this case, the first inner electrode 121 may be exposed from the first surface S1 of the ceramic body 110, and the second inner electrode 122 may be exposed from the second surface S2 of the ceramic body 110.

[0051] The first internal electrode 121 and the second internal electrode 122 may comprise conductive metals. The conductive metals may include, for example, silver (Ag), nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), iron (Fe), gold (Au), silver (Ag), tungsten (W), titanium (Ti), and lead (Pb), and may comprise alloys comprising one or more of these metals. The first internal electrode 121 and the second internal electrode 122 may be formed using a conductive paste comprising conductive metals.

[0052] The multilayer ceramic electronic assembly 100 according to this disclosure may include a first external electrode 131 and a second external electrode 132. The first external electrode 131 includes a first base electrode 131a and a first conductive layer 131b. The first base electrode 131a is connected to a first internal electrode 121 and configured to contact the ceramic body 110. The first conductive layer 131b is disposed on the first base electrode 131a. The second external electrode 132 includes a second base electrode 132a and a second conductive layer 132b. The second base electrode 132a is connected to a second internal electrode 122 and configured to contact the ceramic body 110. The second conductive layer 132b is disposed on the second base electrode 132a. The first base electrode 131a may be disposed on a first surface S1 of the ceramic body 110, and the second base electrode 132a may be disposed on a second surface S2 of the ceramic body 110.

[0053] In exemplary embodiments of this disclosure, the first base electrode 131a and the second base electrode 132a of the multilayer ceramic electronic assembly according to this disclosure may include a conductive metal. The conductive metal may include at least one of, for example, nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), iron (Fe), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), and alloys thereof.

[0054] As an example of a method for forming the first base electrode 131a and the second base electrode 132a, the first base electrode 131a and the second base electrode 132a can be formed by immersing a ceramic body in a conductive paste comprising a conductive metal and sintering the ceramic body, or by printing the conductive paste onto the surface of the ceramic body using screen printing or gravure printing and then sintering the ceramic body. Alternatively, the first base electrode 131a and the second base electrode 132a can be formed by coating the surface of the ceramic body with conductive paste or by transferring a dry film obtained from dried conductive paste onto the ceramic body and then sintering the ceramic body, but the method is not limited to these. For example, the first base electrode 131a and the second base electrode 132a can be formed by forming conductive paste on the ceramic body using various other methods besides those described above, followed by sintering the ceramic body.

[0055] The multilayer ceramic electronic assembly 100 according to the present disclosure may include a first conductive layer 131b disposed on a first base electrode 131a and a second conductive layer 132b disposed on a second base electrode 132a. Figure 5 This is an image of a cross-section of the first external electrode of the multilayer ceramic electronic assembly according to this disclosure. (Refer to...) Figure 5 As can be seen, the first external electrode of the multilayer ceramic electronic component according to the present disclosure has a structure in which a first conductive layer 131b is disposed on a first base electrode 131a.

[0056] In examples of this disclosure, the first conductive layer 131b and the second conductive layer 132b of the multilayer ceramic electronic assembly 100 according to this disclosure may comprise an alloy of silver (Ag) and palladium (Pd). In this case, the average alloying rate of silver (Ag) and palladium (Pd) in the first conductive layer 131b and the second conductive layer 132b may be 95% or higher. In this disclosure, the term "alloying rate" may refer to a ratio (B / A), where B is the weight of the alloy of silver (Ag) and palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b, and A is the sum of the weights of all silver (Ag) and all palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b. The total weight A of all silver (Ag) and all palladium (Pd), and the weight B of the silver (Ag) and palladium (Pd) alloy, can be obtained by analyzing images of the TEM-EDS mapping results of the central portions of the first conductive layer 131b and / or the second conductive layer 132b as described above. Furthermore, in this disclosure, the "average" alloying rate can refer to the arithmetic mean of the alloying rates of samples taken at any five locations within the central portions of the first conductive layer 131b and / or the second conductive layer 132b.

[0057] The average alloying rate of silver (Ag) and palladium (Pd) can be 95% or higher, 96% or higher, 97% or higher, 98% or higher, or 99% or higher, and there is no particular upper limit, but it can be, for example, 100% or lower. If the average alloying rate of silver (Ag) and palladium (Pd) is 100%, then the silver (Ag) and palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b can both be in alloy form. Figure 6 and Figure 7 This is a TEM image of the central region of the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic assembly according to this example. Figure 6 As shown, silver (Ag) and palladium (Pd) in the first conductive layer 131b and / or the second conductive layer 132b can exist as an alloy phase. Figure 7 Show Figure 6 The results of TEM-EDS mapping of the image. (Refer to...) Figure 7 (a) shows that palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b is distributed throughout the entire region of the silver (Ag) and palladium (Pd) alloy. Additionally, referring to... Figure 7 (b) The silver (Ag) included in the first conductive layer 131b and / or the second conductive layer 132b is also distributed throughout the entire region of the silver (Ag) and palladium (Pd) alloy. That is, if the distribution of silver (Ag) and palladium (Pd) is... Figure 7 (a) and Figure 7If all regions of (b) match, it could mean that silver (Ag) and palladium (Pd) exist as an alloy phase.

[0058] In other words, the silver (Ag) or palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic assembly according to this example may exist as a very small amount as a separate component other than the alloy. Typically, when forming the external electrode of a multilayer ceramic electronic assembly, a single-component metal can be used, with some alloys mixed as needed; sometimes, different metal components can be controlled to partially alloy during firing. In particular, in the case of using multilayer external electrodes, in many cases, the metal components included in each layer can be different, and the different metal components can be controlled to form an intermetallic compound (IMC) at the interface of each layer. That is, the external electrode is formed so that the advantageous effects of each component can be utilized. On the other hand, in the multilayer ceramic electronic assembly, an alloy of silver (Ag) and palladium (Pd) is used in the raw material stage for forming the first conductive layer 131b and / or the second conductive layer 132b; therefore, even with the use of a small amount of palladium (Pd), excellent ion migration suppression effects can be obtained. If the average alloying rate of the first conductive layer 131b and / or the second conductive layer 132b is outside the above range, there may be a problem of silver (Ag) component migration when exposed to high temperature environment.

[0059] In one example, the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic component of this disclosure may not contain palladium (Pd) particles with a maximum particle size of 100 nm or larger. A palladium (Pd) particle may refer to a single particle containing only palladium (Pd). As described above, since the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic component according to this disclosure are formed using an alloy of silver (Ag) and palladium (Pd) in the raw material stage, they can have a high alloying rate and may not contain individual palladium (Pd) particles with a predetermined size or larger.

[0060] According to exemplary embodiments of this disclosure, the alloy of silver (Ag) and palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic component may include palladium (Pd) in the range of greater than or equal to 1 wt% and less than or equal to 50 wt%. The palladium (Pd) content in the silver (Ag) and palladium (Pd) alloy may be 1.0 wt% or higher, 1.2 wt% or higher, 1.4 wt% or higher, 1.6 wt% or higher, 1.8 wt% or higher, or 2.0 wt% or higher, and may be 50 wt% or lower, 45 wt% or lower, 40 wt% or lower, 35 wt% or lower, 30 wt% or lower, 25 wt% or lower, or 20 wt% or lower. In the multilayer ceramic electronic assembly according to this disclosure, by applying palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b in the form of an alloy with silver (Ag) during the raw material stage, ion migration of the first conductive layer 131b and / or the second conductive layer 132b can be effectively suppressed even with the use of a small amount of palladium (Pd), thereby improving economic efficiency.

[0061] In exemplary embodiments of this disclosure, the silver (Ag) and palladium (Pd) alloy in the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic component may include a core-shell structure, comprising a core portion and a shell portion. In the core-shell structure of the silver (Ag) and palladium (Pd) alloy, the core portion and the shell portion may have different compositions. In this case, in the core-shell structure, the shell portion may have a higher palladium (Pd) content ratio than the core portion. Figure 8 and Figure 9 This is a TEM image of the central region of the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic assembly according to this exemplary embodiment. Figure 8 As shown, silver (Ag) and palladium (Pd) in the first conductive layer 131b and / or the second conductive layer 132b can exist as an alloy phase. Figure 9 Show Figure 8 The results of TEM-EDS mapping of the image. (Refer to...) Figure 9 (b) shows that the silver (Ag) included in the first conductive layer 131b and / or the second conductive layer 132b is distributed throughout the entire region of the silver (Ag) and palladium (Pd) alloy. Furthermore, referring to… Figure 9 (a) It can be seen that palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b is included in the shell portion in a higher proportion. Even when the alloy of silver (Ag) and palladium (Pd) has a core-shell structure as shown in this exemplary embodiment, ion migration can be effectively suppressed.

[0062] In another exemplary embodiment of this disclosure, the alloy of silver (Ag) and palladium (Pd) in the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic component may include a homogeneous alloy structure. A homogeneous alloy structure can refer to a state where silver (Ag) and palladium (Pd) are uniformly formed into an alloy phase without bias towards any one region. That is, a homogeneous alloy structure can refer to a state with a very high alloying rate. In this case, the palladium (Pd) in the homogeneous alloy structure may have a certain weight ratio in the alloy regions of silver (Ag) and palladium (Pd) in the first and second conductive layers. Figure 10 (a) and Figure 10 (b) shows the results of the TEM-EDS mapping. (Refer to...) Figure 10 (a) and Figure 10 (b) It can be seen that, in the case of this exemplary embodiment, with Figure 9 Unlike the case shown, the alloy of silver (Ag) and palladium (Pd) included in the first conductive layer 131b and / or the second conductive layer 132b is uniformly distributed. When the alloy of silver (Ag) and palladium (Pd) has a homogeneous structure as shown in this exemplary embodiment, excellent ion migration suppression effects can be obtained.

[0063] In examples of this disclosure, the first conductive layer 131b and the second conductive layer 132b of the multilayer ceramic electronic component according to this disclosure may include a glass composition. The glass composition may be a composition mixed with oxides, and may be at least one selected from, but not limited to, the group consisting of silicon dioxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides, and alkaline earth metal oxides. The transition metal may be one or more selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni). The alkali metal may be one or more 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).

[0064] In one example, the first conductive layer 131b and / or the second conductive layer 132b of the multilayer ceramic electronic component according to this disclosure may include a glass composition ranging from 5 wt% to 15 wt%. The glass composition content in the first conductive layer 131b and / or the second conductive layer 132b may refer to the average value of samples taken from any five locations at the central portion of the first conductive layer 131b and / or the second conductive layer 132b. If the glass composition content in the first conductive layer 131b and / or the second conductive layer 132b exceeds 15 wt%, the density of the first conductive layer 131b and / or the second conductive layer 132b may decrease, thereby degrading the durability of the multilayer ceramic electronic component. Additionally, if the glass composition content in the first conductive layer 131b and / or the second conductive layer 132b is less than 5 wt%, the rheological properties may deteriorate, and therefore the first conductive layer 131b and / or the second conductive layer 132b may not be able to be manufactured into the desired shape.

[0065] The method for forming the first conductive layer 131b and the second conductive layer 132b is not particularly limited. For example, the first conductive layer 131b and the second conductive layer 132b can be formed by immersing the ceramic body in a conductive paste comprising an alloy of silver (Ag) and palladium (Pd) and a glass component, or by printing the conductive paste onto the surface of the ceramic body using screen printing or gravure printing. Furthermore, the first conductive layer 131b and the second conductive layer 132b can be formed by coating the conductive paste onto the surface of the ceramic body or by transferring a dry film obtained after drying the conductive paste onto the ceramic body, but the method is not limited to these methods. By using the aforementioned conductive paste to form the first conductive layer 131b and the second conductive layer 132b, sufficient conductivity can be maintained, and the added glass component increases the density of the external electrode, thereby effectively suppressing the penetration of the plating solution and / or external moisture.

[0066] In exemplary embodiments of this disclosure, the first conductive layer 131b and the second conductive layer 132b of the multilayer ceramic electronic assembly according to this disclosure can be configured to cover the first substrate electrode and the second substrate electrode, respectively. In this disclosure, configuring any one layer to cover the other can refer to a structure in which the inner layer is not exposed to the outside, and can also refer to a structure in which the inner layer is disposed inside the outer layer, or a structure in which only the outer layer is visible from the outside. When the first conductive layer and the second conductive layer are configured to cover the first substrate electrode and the second substrate electrode, respectively, as described above, the first conductive layer and the second conductive layer can prevent the first substrate electrode and the second substrate electrode from being exposed to the outside, thereby improving the moisture resistance reliability of the multilayer ceramic electronic assembly.

[0067] In exemplary embodiments of this disclosure, the multilayer ceramic electronic assembly according to this disclosure may, as needed, include plating layers disposed on a first conductive layer and a second conductive layer. The plating layers may be one, two, or more layers, and may be formed by sputtering or electroplating, but are not limited thereto. The materials used to form the plating layers are not particularly limited, and may include individual nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb), or alloys thereof.

[0068] <Examples and Comparison Examples>

[0069] In the example, a paste for an external electrode (e.g., a conductive layer) is prepared using a silver (Ag) and palladium (Pd) alloy with a palladium (Pd) weight ratio of 5 wt% to 20 wt%.

[0070] The prepared paste was applied to a prototype sheet in which the first and second base electrodes were formed using copper (Cu). A product with dimensions of 16 mm × 8 mm × 8 mm (temperature characteristics X7R and capacitance 220.0 nF) for mass production was used as the prototype sheet.

[0071] Prototype sheets coated with a paste for manufacturing a conductive layer were fired at approximately 700°C for about 2 hours to prepare prototype MLCCs.

[0072] In the case of the comparative example, the prototype MLCC was manufactured under the same conditions as the example, except that palladium (Pd) was weighed to a content of 10 wt% and silver (Ag) powder particles and palladium (Pd) powder particles were mixed and used.

[0073] Figure 11 This is a TEM image of a cross-section of a multilayer ceramic electronic component according to a comparative example of this disclosure. Figure 12 It is relative to Figure 11 EDS-mapped images of palladium (Pd) and silver (Ag). Figure 13 This is a TEM image of a cross-section of a multilayer ceramic electronic component according to a comparative example of this disclosure. Figure 14 It is relative to Figure 13 EDS-mapped images of palladium (Pd) and silver (Ag). Figure 15 The results of ion migration tests on prototype MLCCs fabricated in the example and comparative examples are shown.

[0074] Ion migration was tested by adding 1.3 ml of distilled water between the external electrodes at 25°C and 1 atm and applying a 15 V DC power supply to the two external electrodes of the MLCC. After the power was applied, dendrites of the silver (Ag) component were observed to grow from the negative (-) electrode to the positive (+) electrode of the MLCC as ion migration proceeded. A current of 1 mA or greater flowed when the two electrodes of the MLCC were connected to the growing dendrites. This time was measured to compare the degree of ion migration.

[0075] Reference Figure 15 In the comparative example, current flow due to dendrite growth was observed within approximately 30 seconds, but in the example case, no current flow occurred even after 180 seconds. This demonstrates that the multilayer ceramic electronic component according to this disclosure exhibits excellent performance in suppressing ion migration.

[0076] As described above, according to exemplary embodiments of the present disclosure, ion migration in multilayer ceramic electronic components can be suppressed.

[0077] Furthermore, reducing the use of precious metals in multilayer ceramic electronic components can improve economic efficiency.

[0078] In addition, it can improve the reliability of multilayer ceramic electronic components.

[0079] Although exemplary embodiments have been shown and described above, it will be readily understood by those skilled in the art that modifications and changes may be made without departing from the scope of this disclosure as defined by the appended claims.

Claims

1. A multilayer ceramic electronic component, comprising: A ceramic body includes a dielectric layer and alternating stacked first and second inner electrodes, wherein the dielectric layer is located between the first and second inner electrodes; A first external electrode is connected to the first internal electrode and includes a first base electrode and a first conductive layer. The first base electrode is configured to contact the ceramic body, and the first conductive layer is disposed on the first base electrode. as well as A second external electrode is connected to the second internal electrode and includes a second base electrode and a second conductive layer. The second base electrode is configured to contact the ceramic body, and the second conductive layer is disposed on the second base electrode. The first conductive layer and the second conductive layer include Ag and Pd, and according to the results of transmission electron microscopy mapping, the distribution positions of Ag and Pd in ​​the central portion of the first conductive layer and the second conductive layer are matched by 95% or more.

2. The multilayer ceramic electronic component according to claim 1, wherein, The first conductive layer and the second conductive layer comprise an alloy of Ag and Pd, and the average alloying rate of Ag and Pd in ​​the first conductive layer and the second conductive layer is 95% or higher.

3. The multilayer ceramic electronic component according to claim 2, wherein, The content of Pd in ​​the alloy of Ag and Pd is in the range of 1 wt% to 50 wt%.

4. The multilayer ceramic electronic component according to claim 2, wherein, The alloy of Ag and Pd included in the first conductive layer and the second conductive layer includes a core-shell structure and / or a homogeneous alloy structure, wherein the core-shell structure includes a core portion and a shell portion.

5. The multilayer ceramic electronic component according to claim 4, wherein, The Pd content in the core-shell structure is higher in the shell portion than in the core portion.

6. The multilayer ceramic electronic component according to claim 4, wherein, The Pd in ​​the homogeneous alloy structure has a certain weight ratio in the alloy regions of Ag and Pd in ​​the first conductive layer and the second conductive layer.

7. The multilayer ceramic electronic component according to claim 1, wherein, The first conductive layer and / or the second conductive layer do not include Pd particles with a maximum particle size of 100 nm or larger.

8. The multilayer ceramic electronic component according to claim 1, wherein, The first conductive layer and the second conductive layer comprise glass components.

9. The multilayer ceramic electronic component according to claim 8, wherein, The glass composition included in the first conductive layer and the second conductive layer is in the range of 5 wt% to 15 wt%.

10. The multilayer ceramic electronic component according to claim 8, wherein, The glass composition is selected from one or more of the group consisting of silicon dioxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides and alkaline earth metal oxides.

11. The multilayer ceramic electronic component according to claim 1, wherein, The first conductive layer is configured to cover the first base electrode, and the second conductive layer is configured to cover the second base electrode.

12. The multilayer ceramic electronic component according to claim 1, wherein, The first base electrode and the second base electrode comprise one or more conductive materials selected from the group consisting of Ni, Cu, Sn, Pd, Pt, Fe, Au, Ag, W, Ti, Pb and alloys thereof.

13. The multilayer ceramic electronic component according to claim 1, wherein the multilayer ceramic electronic component further comprises a plating layer disposed on the first conductive layer and the second conductive layer.

14. A multilayer ceramic electronic component, comprising: The ceramic body has a first side surface and a second side surface that are opposite to each other in the longitudinal direction; A first external electrode and a second external electrode are respectively disposed on the first side surface and the second side surface. Each of the first external electrode and the second external electrode includes a base electrode layer disposed on the respective side surface and a conductive layer disposed on the base electrode layer. The conductive layer comprises an Ag-Pd alloy having an average alloying rate of higher than 95%. The alloying rate is defined as the ratio B / A, where B is the weight of the Ag-Pd alloy and A is the sum of the total weight of Ag and the total weight of Pd.

15. The multilayer ceramic electronic component according to claim 14, wherein, The Pd content in the conductive layer is in the range of 1 wt% to 50 wt%.

16. The multilayer ceramic electronic component according to claim 14, wherein, The conductive layer also includes a glass component in the range of 5 wt% to 15 wt%.

17. The multilayer ceramic electronic component according to claim 16, wherein, The glass composition includes one or more oxides selected from Si, B, Al, Zn, Ti, Cu, V, Mn, Fe, Ni, Li, Na, K, Mg, Ca, Sr, and Ba.

18. The multilayer ceramic electronic component according to claim 14, further comprising a plating layer disposed on the conductive layer, the plating layer comprising one or more of Ni, Cu, Sn, Pd, Pt, Au, Ag, W, Ti, Pb and alloys thereof.

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