Multilayer ceramic capacitor and method for manufacturing the same

Abstract

This invention provides a highly reliable multilayer ceramic capacitor. It also provides a method for manufacturing the multilayer ceramic capacitor. [Solution] A multilayer ceramic capacitor is provided, comprising a capacitor body including a dielectric layer and an internal electrode layer, and an external electrode disposed on the outside of the capacitor body, wherein the internal electrode layer includes a first internal electrode layer and a second internal electrode layer laminated spaced apart from each other with the dielectric layer in between, the first internal electrode layer and the second internal electrode layer each contain one or more elements selected from aluminum (Al), silicon (Si), germanium (Ge), zinc (Zn), tin (Sn), indium (In), and iron (Fe), and the first internal electrode layer and the second internal electrode layer each contain different elements, and a method for manufacturing the same.

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic capacitor and a method for manufacturing the same.

Background Art

[0002] As electronic components using ceramic materials, there are capacitors, inductors, piezoelectric elements, varistors, thermistors, etc. Among such ceramic electronic components, multilayer ceramic capacitors (MLCCs) can be used in various electronic devices due to their advantages of being small in size, having a high capacitance, and being easy to mount.

[0003] For example, a multilayer ceramic capacitor (MLCC) can be used as a chip-shaped capacitor that is attached to the substrates of various electronic products such as liquid crystal display devices (LCDs), plasma display panels (PDPs), organic light-emitting diodes (OLEDs), computers, personal mobile terminals, and smartphones, and plays a role in charging or discharging electricity.

[0004] Recently, with the development of electronic devices and autonomous driving vehicles, miniaturization and high capacitance of multilayer ceramic capacitors have been greatly demanded. In order to achieve a higher capacitance in the same volume, thinning of the internal electrodes and the dielectric layer is essential. However, as the dielectric and the internal electrodes are thinned, the electric field applied per unit thickness of the dielectric increases, leading to deterioration of the reliability of the multilayer ceramic capacitor.

Summary of the Invention

Problems to be Solved by the Invention

[0005] One embodiment provides a multilayer ceramic capacitor with excellent reliability.

[0006] Another embodiment provides a method for manufacturing the multilayer ceramic capacitor. [Means for solving the problem]

[0007] One embodiment provides a multilayer ceramic capacitor comprising a capacitor body including a dielectric layer and an internal electrode layer, and an external electrode disposed on the outside of the capacitor body, wherein the internal electrode layer includes a first internal electrode layer and a second internal electrode layer laminated spaced apart from each other with the dielectric layer in between, the first internal electrode layer and the second internal electrode layer each contain one or more elements selected from aluminum (Al), silicon (Si), germanium (Ge), zinc (Zn), tin (Sn), indium (In), and iron (Fe), and the first internal electrode layer and the second internal electrode layer each contain different elements. The first internal electrode layer may contain one or more elements (X1) selected from aluminum (Al), silicon (Si), and germanium (Ge), and the second internal electrode layer may contain one or more elements (X2) selected from zinc (Zn), tin (Sn), indium (In), and iron (Fe).

[0008] The first internal electrode layer may be given a cathode potential, and the second internal electrode layer may be given an anode potential.

[0009] The first internal electrode layer and the second internal electrode layer may further contain nickel (Ni).

[0010] The first internal electrode layer may contain nickel (Ni) and germanium (Ge), and the second internal electrode layer may contain nickel (Ni) and tin (Sn).

[0011] The element (X1) in the first internal electrode layer may be present in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni).

[0012] The element (X2) in the second internal electrode layer may be present in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni).

[0013] In the first internal electrode layer, the content of element (X1) may be even higher at the interface between the first internal electrode layer and the dielectric layer than at the central region of the first internal electrode layer in the stacking direction.

[0014] The element (X1) in the first internal electrode layer may be present in oxide form at the interface with the dielectric layer.

[0015] In the second internal electrode layer, the content of element (X2) may be even higher at the interface between the second internal electrode layer and the dielectric layer than at the central region of the second internal electrode layer in the stacking direction.

[0016] The element (X2) in the second internal electrode layer may be present in oxide form at the interface with the dielectric layer.

[0017] Another embodiment provides a method for manufacturing a multilayer ceramic capacitor, comprising the steps of: manufacturing a dielectric green sheet using a dielectric slurry; printing a first conductive paste on the surface of the dielectric green sheet to form a first conductive paste layer; printing a second conductive paste on the surface of the dielectric green sheet to form a second conductive paste layer; alternately stacking dielectric green sheets having the first conductive paste layer and dielectric green sheets having the second conductive paste layer to manufacture a dielectric green sheet laminate; firing the dielectric green sheet laminate to manufacture a capacitor body including a dielectric layer and an internal electrode layer; and forming an external electrode on the outside of the capacitor body, wherein the internal electrode layer includes a first internal electrode layer and a second internal electrode layer stacked spaced apart from each other with the dielectric layer in between, the first conductive paste and the second conductive paste are manufactured from raw materials including one or more metals selected from Al, Si, Ge, Zn, Sn, In, and Fe, an alloy of the metal and Ni, or an oxide of the metal, and the first conductive paste and the second conductive paste are manufactured from different raw materials.

[0018] The first conductive paste may be manufactured from a raw material containing one or more metals (M1) selected from Al, Si, and Ge, an alloy of the metal (M1) and Ni, or an oxide of the metal (M1), and the second conductive paste may be manufactured from a raw material containing one or more metals (M2) selected from Zn, Sn, In, and Fe, an alloy of the metal (M2) and Ni, or an oxide of the metal (M2).

[0019] The first conductive paste and the second conductive paste may be manufactured further containing nickel (Ni).

[0020] The raw materials for the first conductive paste may contain the metal (M1) in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni).

[0021] The raw material of the second conductive paste may be contained in a content such that the metal (M2) is 0.1 part by weight to 8 parts by weight with respect to 100 parts by weight of the nickel (Ni).

Advantages of the Invention

[0022] A multilayer ceramic capacitor according to an embodiment can improve reliability by preventing deterioration of an interfacial potential barrier between a dielectric layer and an internal electrode layer.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor cut along the line I-I' of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor cut along the line II-II' of FIG. 1. [Figure 4] FIG. 4 is a separated perspective view showing a stacked structure of an internal electrode layer in the capacitor body of FIG. 1. [Figure 5] FIG. 5 shows an Ellingham diagram of nickel (Ni), tin (Sn), and germanium (Ge).​​​​​​​​​​Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. In the drawings, parts that are not necessary for the clear explanation of the present invention have been omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. In addition, some components in the attached drawings are exaggerated, omitted, or shown schematically, and the size of each component does not fully reflect its actual size.

[0025] The accompanying drawings are provided solely to facilitate understanding of the embodiments disclosed herein, and should not be understood as limiting the technical ideas disclosed herein, and should be understood to include any modifications, equivalents, or substitutions that fall within the concept and scope of the invention.

[0026] Terms including ordinal numbers, such as "first," "second," etc., can be used to describe a variety of components, but the components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0027] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on top of" another part, this includes not only the case where it is "directly above" the other part, but also the case where the other part is in between. Conversely, when we say that one part is "directly above" another part, it means that there is no other part in between. Also, being "on top of" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" in the opposite direction of gravity.

[0028] Throughout the specification, terms such as “includes” or “have” are intended to specify the presence of features, figures, steps, actions, components, parts, or combinations thereof described in the specification, and should not be understood to preemptively exclude the presence or possibility of adding one or more other features, figures, steps, actions, components, parts, or combinations thereof. Therefore, when a part “includes” a component, this means that, unless otherwise stated, it does not exclude other components and may further include other components.

[0029] Furthermore, throughout the specification, "on a plane" refers to the view of the part in question from above, and "on a cross-section" refers to the view of a cross-section of the part in question, obtained by cutting it perpendicularly, from the side.

[0030] Furthermore, throughout the specification, the term "connected" does not only mean that two or more components are directly connected, but may also mean that two or more components are indirectly connected through other components, that they are not only physically connected but also electrically connected, or that they are a single unit, even though they are referred to by different names depending on their location or function.

[0031] Hereinafter, a multilayer ceramic capacitor according to one embodiment will be described with reference to Figures 1 to 4.

[0032] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to one embodiment; Figure 2 is a cross-sectional view of the multilayer ceramic capacitor cut along the line I-I' in Figure 1; Figure 3 is a cross-sectional view of the multilayer ceramic capacitor cut along the line II-II' in Figure 1; and Figure 4 is a separated perspective view showing the laminated structure of the internal electrode layers in the capacitor body of Figure 1.

[0033] The L-axis, W-axis, and T-axis shown in Figures 1 to 4 represent the length, width, and thickness directions of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) may be perpendicular to the broad surface (main surface) of the sheet-shaped component, and for example, it can be used as the same concept as the stacking direction in which the dielectric layers 111 are stacked. The length direction (L-axis direction) may be a direction that extends alongside the broad surface (main surface) of the sheet-shaped component and is approximately perpendicular to the thickness direction (T-axis direction), and for example, it may be a direction in which the first external electrode 131 and the second external electrode 132 are located on both sides. The width direction (W-axis direction) may be a direction that extends alongside the broad surface (main surface) of the sheet-shaped component and is approximately perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length in the length direction (L-axis direction) of the sheet-shaped component may be even longer than the length in the width direction (W-axis direction).

[0034] Referring to Figures 1 to 4, a multilayer ceramic capacitor 100 according to one embodiment includes a capacitor body 110 and external electrodes 131 and 132 disposed on the outside of the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 disposed at opposing ends of the capacitor body 110 in the longitudinal direction (L-axis direction).

[0035] The capacitor body 110 may, for example, be roughly hexahedral in shape.

[0036] For the convenience of explaining one embodiment, the two surfaces of the capacitor body 110 that face each other in the thickness direction (T-axis direction) are defined as the first and second surfaces, the two surfaces connected to the first and second surfaces that face each other in the length direction (L-axis direction) are defined as the third and fourth surfaces, and the two surfaces connected to the first and second surfaces that face each other in the width direction (W-axis direction) are defined as the fifth and sixth surfaces.

[0037] For example, the first surface, which is the bottom surface, may be the surface facing the mounting direction. Also, the first to sixth surfaces may be flat, but this is not the only embodiment. For example, the first to sixth surfaces may be curved surfaces with a convex central portion, and the corners that form the boundaries of each surface may be rounded.

[0038] The shape, size, and number of dielectric layers 111 of the capacitor body 110 are not limited to those shown in the drawings of this embodiment.

[0039] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrode layers 121 and 122. Specifically, the internal electrode layers 121 and 122 include a first internal electrode layer 121 and a second internal electrode layer 122 that are spaced apart from each other with the dielectric layer 111 in between, that is, alternately arranged in the thickness direction (T-axis direction).

[0040] At this time, the boundaries between adjacent dielectric layers 111 of the capacitor body 110 may be so integrated that they are difficult to confirm without using a scanning electron microscope (SEM).

[0041] The capacitor body 110 may include an active region and cover regions 112, 113.

[0042] The active region is a region in which the dielectric layer 111 and the internal electrode layers 121 and 122 are arranged alternately, and is the part that contributes to the formation of the capacitance of the multilayer ceramic capacitor 100. Specifically, the active region may be a region in which the first internal electrode layer 121 or the second internal electrode layer 122, which are stacked along the thickness direction (T-axis direction), overlap.

[0043] The cover regions 112 and 113 are thickness-direction margins and can be located on the first and second surfaces of the active region in the thickness direction (T-axis direction), respectively. Such cover regions 112 and 113 may be formed by a single dielectric layer 111 or by two or more dielectric layers 111 being laminated on the upper and lower surfaces of the active region, respectively.

[0044] Furthermore, the capacitor body 110 may also include a side margin region.

[0045] The side margin region is a widthwise margin portion and can be located on both opposite ends of the active region in the widthwise direction (W-axis direction), i.e., on the fifth and sixth surfaces, respectively. The side margin region can be formed by applying a conductive paste layer for the internal electrode layer to the surface of the dielectric green sheet, applying the conductive paste layer only to a portion of the surface of the dielectric green sheet, and then stacking dielectric green sheets without the conductive paste layer on both sides of the surface of the dielectric green sheet, followed by firing, but is not limited to this method of formation.

[0046] The cover regions 112, 113 and the side margin regions serve to prevent damage to the first internal electrode layer 121 and the second internal electrode layer 122 due to physical or chemical stress.

[0047] The internal electrode layer, dielectric layer, and external electrode will be explained in detail below.

[0048] <Internal electrode layer> The internal electrode layers 121 and 122, that is, the first internal electrode layer 121 and the second internal electrode layer 122, are electrodes having different polarities, and are arranged alternately facing each other along the T-axis direction with the dielectric layer 111 in between, with one end of each electrode being exposed through the third and fourth surfaces of the capacitor body 110.

[0049] The first internal electrode layer 121 and the second internal electrode layer 122 can be electrically insulated from each other by the dielectric layer 111 placed in between them.

[0050] The ends of the first internal electrode layer 121 and the second internal electrode layer 122, which are alternately exposed through the third and fourth surfaces of the capacitor body 110, can be electrically connected to the first external electrode 131 and the second external electrode 132, respectively.

[0051] For example, the first internal electrode layer 121, which is electrically connected to the first external electrode 131, is a cathode corresponding to the negative electrode (- electrode), and a cathode potential may be applied to the first internal electrode layer 121. The second internal electrode layer 122, which is electrically connected to the second external electrode 132, is an anode corresponding to the positive electrode (+ electrode), and an anode potential may be applied to the second internal electrode layer 122.

[0052] According to one embodiment, the first internal electrode layer 121 and the second internal electrode layer 122 may contain one or more elements selected from aluminum (Al), silicon (Si), germanium (Ge), zinc (Zn), tin (Sn), indium (In), and iron (Fe). In this case, the first internal electrode layer 121 and the second internal electrode layer 122 may contain different elements from each other.

[0053] Generally, an interfacial potential barrier is formed at the interface between the dielectric layer and the internal electrode layer. Increasing the magnitude of this interfacial potential barrier can improve the reliability of multilayer ceramic capacitors. One method for evaluating the lifespan of multilayer ceramic capacitors is accelerated lifetime evaluation, which involves applying high temperature and high voltage across the chip. When performing accelerated lifetime evaluation, applying voltage across the chip causes degradation of the interfacial potential barrier. If the degradation becomes severe, a short circuit may occur, causing the multilayer ceramic capacitor to lose its function.

[0054] According to one embodiment, when the first internal electrode layer 121 and the second internal electrode layer 122 contain different elements, specifically, different elements from among Al, Si, Ge, Zn, Sn, In, and Fe, the reliability of the multilayer ceramic capacitor can be improved by preventing deterioration of the interfacial potential barrier formed at the interface between the dielectric layer 111 and the internal electrode layers 121 and 122.

[0055] Specifically, the first internal electrode layer 121 to which the cathode potential is applied may contain elements that can be oxidized and act as an insulator. In other words, the elements of the first internal electrode layer 121 may form an insulator with a large band gap energy of oxide. For example, the first internal electrode layer 121 may contain one or more elements (X1) selected from aluminum (Al), silicon (Si), and germanium (Ge), for example, germanium (Ge). When the first internal electrode layer 121 contains the element (X1), an oxide layer is formed at the interface between the dielectric layer 111 and the first internal electrode layer 121, thereby improving the degradation of the interface potential barrier in the cathode direction.

[0056] Furthermore, the second internal electrode layer 122 to which the anode potential is applied may contain elements that can be oxidized and act as an n-type semiconductor. In other words, the elements of the second internal electrode layer 122 may form an n-type semiconductor with a small bandgap energy for the oxide relative to the insulator. For example, the second internal electrode layer 122 may contain one or more elements (X2) selected from zinc (Zn), tin (Sn), indium (In), and iron (Fe), for example, tin (Sn). When the second internal electrode layer 122 contains the element (X2), an oxide layer is formed at the interface between the dielectric layer 111 and the second internal electrode layer 122, thereby improving the degradation of the interface potential barrier in the anode direction.

[0057] In other words, when the first internal electrode layer 121 and the second internal electrode layer 122 each contain the aforementioned elements, oxide layers of each component are formed at the interface between the dielectric layer and the internal electrode layers during firing, thereby preventing deterioration of the interfacial potential barrier in both the cathode and anode directions. This improves the reliability of the multilayer ceramic capacitor.

[0058] The first internal electrode layer 121 and the second internal electrode layer 122 may further contain nickel (Ni).

[0059] Figure 5 shows the Ellingham diagrams for nickel (Ni), tin (Sn), and germanium (Ge).

[0060] As shown in Figure 5, germanium (Ge) and tin (Sn) are elements that oxidize more readily than nickel (Ni). When Ge and Sn are included in the internal electrode layer, Ni acts as a catalyst to promote the reduction of oxides, resulting in the coexistence of GeO2 and Ge with SnO2 and Sn during firing. Of these, some form a solid solution with Ni within the internal electrode layer, and some form GeO2 and SnO2 layers at the interface between the dielectric layer and the internal electrode layer. Both the GeO2 and SnO2 layers can increase the potential barrier at the interface between the dielectric layer and the internal electrode layer, thereby improving the reliability of the multilayer ceramic capacitor. Specifically, n-type semiconductor materials such as the SnO2 layer prevent degradation of the potential barrier on the anode side, and insulator materials such as the GeO2 layer prevent degradation of the potential barrier on the cathode side, thereby improving the reliability of the multilayer ceramic capacitor.

[0061] For example, the first internal electrode layer 121 may contain nickel (Ni) and germanium (Ge). The second internal electrode layer 122 may contain nickel (Ni) and tin (Sn).

[0062] The element (X1) in the first internal electrode layer 121 may be present in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni), for example, 0.2 to 7 parts by weight, 0.3 to 6 parts by weight, 0.4 to 5 parts by weight, or 0.5 to 4 parts by weight. When the element (X1) content in the first internal electrode layer is within the above range, deterioration of the interfacial potential barrier between the dielectric layer and the internal electrode layer is prevented, ensuring a highly reliable multilayer ceramic capacitor.

[0063] The element (X2) in the second internal electrode layer may be present in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni), for example, 0.2 to 7 parts by weight, 0.3 to 6 parts by weight, 0.4 to 5 parts by weight, or 0.5 to 4 parts by weight. When the element (X2) content in the second internal electrode layer is within the above range, deterioration of the interfacial potential barrier between the dielectric layer and the internal electrode layer is prevented, ensuring a highly reliable multilayer ceramic capacitor.

[0064] The first internal electrode layer 121 and the second internal electrode layer 122 may further contain one or more conductive metals selected from copper (Cu), silver (Ag), palladium (Pd), gold (Au), and alloys thereof, in addition to nickel (Ni).

[0065] In the first internal electrode layer 121, the content of element (X1) may be even higher at the interface with the dielectric layer 111 than at the central region of the first internal electrode layer 121 in the stacking direction. When the content of element (X1) is even higher at the interface between the first internal electrode layer 121 and the dielectric layer 111, the reliability of the multilayer ceramic capacitor can be improved by preventing deterioration of the interfacial potential barrier formed at the interface between the dielectric layer and the internal electrode layer. In the first internal electrode layer 121, the central region is a region located inward from the interface between the first internal electrode layer 121 and the dielectric layer 111 in the stacking direction, and the interface with the dielectric layer 111 is the interface between the first internal electrode layer 121 and the dielectric layer 111, located outward from the central region in the stacking direction. Specifically, the interface can also be seen as a region extending from the interface between the first internal electrode layer 121 and the dielectric layer 111 to a depth of 5 nm inside the first internal electrode layer 121.

[0066] The element (X1) of the first internal electrode layer 121 may be present in oxide form at the interface with the dielectric layer 111. In other words, the interface between the first internal electrode layer 121 and the dielectric layer 111 may contain an oxide of element (X1), and may contain one or more selected from, for example, aluminum oxide (Al2O3), silicon dioxide (SiO2), and germanium oxide (GeO2).

[0067] Furthermore, in the second internal electrode layer 122, the content of element (X2) may be even higher at the interface with the dielectric layer 111 than in the central region of the second internal electrode layer 122 in the stacking direction. When the content of element (X2) is even higher at the interface between the second internal electrode layer 122 and the dielectric layer 111, the reliability of the multilayer ceramic capacitor can be improved by preventing deterioration of the interfacial potential barrier formed at the interface between the dielectric layer and the internal electrode layer. In the second internal electrode layer 122, the central region is the region located inward from the interface between the second internal electrode layer 122 and the dielectric layer 111 in the stacking direction, and the interface with the dielectric layer 111 is the interface between the second internal electrode layer 122 and the dielectric layer 111, located outward from the central region in the stacking direction. Specifically, the interface can also be seen as the region from the interface between the second internal electrode layer 122 and the dielectric layer 111 to a depth of 5 nm inside the second internal electrode layer 122.

[0068] The element (X2) of the second internal electrode layer 122 may be present in oxide form at the interface with the dielectric layer 111. In other words, the interface between the second internal electrode layer 122 and the dielectric layer 111 may contain an oxide of element (X2), such as one or more selected from zinc oxide (ZnO), tin oxide (SnO2), indium oxide (In2O3), and iron oxide (FeO, Fe3O4, Fe2O3).

[0069] The components and their content in the first internal electrode layer 121 and the second internal electrode layer 122 can be confirmed by SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis.

[0070] Specifically, after curing the multilayer ceramic capacitor 100 in an epoxy mixture, the L-axis and T-axis surfaces (LT surfaces) of the capacitor body 110 are polished to half a depth in the W-axis direction. After fixing, the sample is maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample that allows observation of the active region where the dielectric layer 111 and the internal electrode layers 121 and 122 intersect. Next, the cross-sectional sample can be measured using a scanning electron microscope (SEM) so that at least two layers, for example, two to ten layers, of the dielectric layer and internal electrode layer are visible in the active region. For example, the SEM can be used to measure an area of ​​approximately 8 μm × 8 μm where six layers of the dielectric layer and six layers of the internal electrode layer are visible in the active region, under conditions of an acceleration voltage of 2.0 kV. Next, EDS (energy-dispersive spectroscopy) analysis is performed on the first internal electrode layer 121 and the second internal electrode layer 122 through SEM images of the measured cross-sectional sample to confirm the components present in the first internal electrode layer 121 and the second internal electrode layer 122, respectively, and their content. For example, the content of each component in the first internal electrode layer and the second internal electrode layer according to one embodiment can be obtained by dividing the active region of the cross-sectional sample into three equal parts: upper, middle, and lower, taking three points in the first internal electrode layer and three points in the second internal electrode layer for each region, and averaging the values ​​of a total of nine points from the first and second internal electrode layers.

[0071] The average thickness of the first internal electrode layer 121 and the second internal electrode layer 122 may be 0.1 μm to 2 μm. When the average thickness of the first internal electrode layer 121 and the second internal electrode layer 122 is within the above range, the reliability of the multilayer ceramic capacitor is excellent.

[0072] This can be determined by using a scanning electron microscope (SEM) image of the cross-sectional sample measured as described above, with the center point in the length direction (L-axis direction) or width direction (W-axis direction) of the first internal electrode layer 121 or the second internal electrode layer 122 as the reference point, and calculating the arithmetic mean of the thickness of the first internal electrode layer 121 or the second internal electrode layer 122 at 10 points separated by a predetermined interval from the reference point. The interval of the 10 points can be adjusted by the scale of the scanning electron microscope (SEM) image, for example, between 1 μm and 100 μm, between 1 μm and 50 μm, or between 1 μm and 10 μm. In this case, all 10 points must be located within the first internal electrode layer 121 or the second internal electrode layer 122. If all 10 points are not located within the first internal electrode layer 121 or the second internal electrode layer 122, the position of the reference point can be changed or the interval between the 10 points can be adjusted.

[0073] <Dielectric layer> In one embodiment, the dielectric layer 111 may mainly contain a barium titanate-based compound containing barium (Ba) and titanium (Ti).

[0074] Barium titanate compounds are dielectric base materials that have a high dielectric constant and contribute to the formation of the dielectric constant of the multilayer ceramic capacitor 100.

[0075] As an example, barium titanate compounds may include one or more selected from BaTiO3, Ba(Ti,Zr)O3, Ba(Ti,Sn)O3, (Ba,Ca)TiO3, (Ba,Ca)(Ti,Zr)O3, (Ba,Ca)(Ti,Sn)O3, (Ba,Sr)TiO3, (Ba,Sr)(Ti,Zr)O3, and (Ba,Sr)(Ti,Sn)O3.

[0076] The dielectric layer 111 may further contain minor components. These minor components may include one or more selected from, for example, manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), ruthenium (Lu), hafnium (Hf), and vanadium (V).

[0077] The average thickness (average length in the T-axis direction) of the dielectric layer 111 may be 0.1 μm to 8.0 μm, for example, 0.1 μm to 6.0 μm. When the average thickness of the dielectric layer 111 is within the above range, the reliability of the multilayer ceramic capacitor is excellent.

[0078] This can be determined by using a scanning electron microscope (SEM) image of the cross-sectional sample measured as described above, with the center of the dielectric layer 111 in the length direction (L-axis direction) or width direction (W-axis direction) as the reference point, and calculating the arithmetic mean of the dielectric layer 111 thickness at 10 points separated by a predetermined interval from the reference point. The interval of the 10 points can be adjusted by the scale of the scanning electron microscope (SEM) image, for example, between 1 μm and 100 μm, between 1 μm and 50 μm, or between 1 μm and 10 μm. In this case, all 10 points must be located within the dielectric layer 111. If all 10 points are not located within the dielectric layer 111, the position of the reference point can be changed or the interval between the 10 points can be adjusted.

[0079] The capacitor body 110 can be formed by firing a laminate in which multiple dielectric layers 111 and internal electrode layers 121 and 122 are stacked.

[0080] <External electrode> The external electrodes 131 and 132, namely the first external electrode 131 and the second external electrode 132, are supplied with voltages of different polarities from each other and can be electrically connected to the exposed portions of the first internal electrode layer 121 and the second internal electrode layer 122, respectively.

[0081] With the above configuration, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charge is accumulated between the first internal electrode layer 121 and the second internal electrode layer 122, which face each other. At this time, the capacitance of the multilayer ceramic capacitor 100 will be proportional to the overlapping area of ​​the first internal electrode layer 121 and the second internal electrode layer 122, which overlap each other along the T-axis in the active region.

[0082] The first external electrode 131 and the second external electrode 132 are arranged on the third and fourth surfaces of the capacitor body 110, respectively, and may include first and second connection portions that connect to the first internal electrode layer 121 and the second internal electrode layer 122, and first and second band portions that are arranged at the corners where the third and fourth surfaces of the capacitor body 110 meet the first and second surfaces or the fifth and sixth surfaces.

[0083] The first band portion and the second band portion can extend to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 at the first and second connection portions, respectively. The first band portion and the second band portion can serve to improve the fixing strength of the first external electrode 131 and the second external electrode 132.

[0084] The first external electrode 131 and the second external electrode 132 may each include a sintered metal layer in contact with the capacitor body 110, a conductive resin layer positioned to cover the sintered metal layer, and a plating layer positioned to cover the conductive resin layer.

[0085] The sintered metal layer may contain conductive metals and glass.

[0086] The conductive metal may include one or more selected from copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), and alloys thereof. For example, copper (Cu) may include copper (Cu) alloys. If the conductive metal includes copper, other metals may be included in amounts of 5 moles or less per 100 moles of copper.

[0087] The glass may contain a composition of mixed oxides, for example, 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 may be 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 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).

[0088] Selectively, the conductive resin layer may be formed on a sintered metal layer, for example, in a form that completely covers the sintered metal layer. On the other hand, the first external electrode 131 and the second external electrode 132 may not include a sintered metal layer, in which case the conductive resin layer can be in direct contact with the capacitor body 110.

[0089] The conductive resin layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the band portion) in which the conductive resin layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the band portion) in which the sintered metal layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110. In other words, the conductive resin layer may be formed on the sintered metal layer and may be formed in a manner that completely covers the sintered metal layer.

[0090] The conductive resin layer contains a resin and a conductive metal.

[0091] The resin contained in the conductive resin layer is not particularly limited as long as it has bonding and shock-absorbing properties and can be mixed with conductive metal powder to make a paste, and may include, for example, phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0092] The conductive metal contained in the conductive resin layer serves to electrically connect with the first internal electrode layer 121 and the second internal electrode layer 122 or the sintered metal layer.

[0093] The conductive metal contained in the conductive resin layer may be spherical, flake-shaped, or a combination of these forms. In other words, the conductive metal may consist solely of flake-shaped elements, solely of spherical elements, or a mixture of flake-shaped and spherical elements.

[0094] Here, "spherical" can include forms that are not perfectly spherical, for example, forms in which the ratio of the length of the long axis to the short axis (long axis / short axis) is 1.45 or less. Flake-shaped powder means powder having a flat and elongated form and is not particularly limited, but for example, the ratio of the length of the long axis to the short axis (long axis / short axis) may be 1.95 or more.

[0095] The first external electrode 131 and the second external electrode 132 may further include a plating layer located on the outside of the conductive resin layer.

[0096] The plating layer may include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb), either alone or in alloys thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or it may be a configuration in which nickel (Ni) plating layers and tin (Sn) plating layers are sequentially laminated, or it may be a configuration in which tin (Sn) plating layers, nickel (Ni) plating layers, and tin (Sn) plating layers are sequentially laminated. The plating layer may also include multiple nickel (Ni) plating layers and / or multiple tin (Sn) plating layers.

[0097] The plating layer can improve the mountability of the multilayer capacitor 100 on the substrate, structural reliability, durability against external elements, heat resistance, and equivalent series resistance (ESR).

[0098] <Manufacturing method for multilayer ceramic capacitors> The following describes a method for manufacturing a multilayer ceramic capacitor 100 according to one embodiment.

[0099] A multilayer ceramic capacitor 100 according to one embodiment may be manufactured by the following steps: manufacturing a dielectric green sheet using a dielectric slurry; printing a first conductive paste on the surface of the dielectric green sheet to form a first conductive paste layer and printing a second conductive paste on the surface of the dielectric green sheet to form a second conductive paste layer; alternately stacking dielectric green sheets having the first conductive paste layer and dielectric green sheets having the second conductive paste layer to manufacture a dielectric green sheet laminate; firing the dielectric green sheet laminate to manufacture a capacitor body including a dielectric layer and an internal electrode layer; and forming an external electrode on the outside of the capacitor body.

[0100] The first conductive paste and the second conductive paste may be manufactured from raw materials containing one or more metals selected from Al, Si, Ge, Zn, Sn, In, and Fe, alloys of the metals with Ni, or oxides of the metals. In this case, the first conductive paste and the second conductive paste may be manufactured from different raw materials.

[0101] Specifically, the first conductive paste may be manufactured from raw materials containing one or more metals (M1) selected from Al, Si, and Ge, an alloy of the metal (M1) with Ni, or an oxide of the metal (M1). The second conductive paste may be manufactured from raw materials containing one or more metals (M2) selected from Zn, Sn, In, and Fe, an alloy of the metal (M2) with Ni, or an oxide of the metal (M2).

[0102] When a first conductive paste and a second conductive paste are manufactured using the respective components described above to form a first internal electrode layer and a second internal electrode layer, a highly reliable multilayer ceramic capacitor can be obtained by preventing deterioration of the interfacial potential barrier between the dielectric layer and the internal electrode layer.

[0103] The first conductive paste and the second conductive paste may be manufactured further containing nickel (Ni).

[0104] The raw materials for the first conductive paste may contain the metal (M1) in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni), for example, 0.2 to 7 parts by weight, 0.3 to 6 parts by weight, 0.4 to 5 parts by weight, or 0.5 to 4 parts by weight.

[0105] Furthermore, the raw materials for the second conductive paste may contain the metal (M2) in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni), for example, 0.2 to 7 parts by weight, 0.3 to 6 parts by weight, 0.4 to 5 parts by weight, or 0.5 to 4 parts by weight.

[0106] When the raw materials for the first conductive paste and the raw materials for the second conductive paste are mixed within the aforementioned content range, a highly reliable multilayer ceramic capacitor can be obtained by preventing deterioration of the interfacial potential barrier between the dielectric layer and the internal electrode layer.

[0107] The first conductive paste and the second conductive paste may further contain one or more conductive metals selected from copper (Cu), silver (Ag), palladium (Pd), gold (Au), and alloys thereof, in addition to nickel (Ni).

[0108] The first conductive paste and the second conductive paste may be manufactured by further mixing in a binder and a solvent. Additionally, barium titanate powder may be mixed in as a void material if necessary. The void material can suppress the sintering of the conductive powder during the firing process.

[0109] The dielectric slurry may be manufactured by selectively mixing a barium titanate-based compound, which is the main component powder, with a secondary component powder.

[0110] Barium titanate compounds may include one or more selected from BaTiO3, Ba(Ti,Zr)O3, Ba(Ti,Sn)O3, (Ba,Ca)TiO3, (Ba,Ca)(Ti,Zr)O3, (Ba,Ca)(Ti,Sn)O3, (Ba,Sr)TiO3, (Ba,Sr)(Ti,Zr)O3, and (Ba,Sr)(Ti,Sn)O3.

[0111] The auxiliary powder may be one or more oxide or salt compounds selected from, for example, Mn, Cr, Si, Al, Mg, Sn, Sb, Ge, Ga, In, Ba, La, Y, Ac, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, and V, or it may be used in sol form dispersed in an organic solvent.

[0112] Furthermore, dielectric slurry may be manufactured by additionally mixing a solvent with additives such as dispersants, binders, plasticizers, lubricants, and antistatic agents.

[0113] The dispersant may include at least one selected from, for example, phosphate ester-based dispersants and polycarboxylic acid-based dispersants. The dispersant may be mixed in an amount of 0.1 to 5 parts by weight, or for example, 0.3 to 3 parts by weight, per 100 parts by weight of the barium titanate compound. When the dispersant is mixed within the above content range, the dispersibility of the dielectric slurry is excellent, and the amount of impurities contained in the manufactured dielectric layer can be reduced.

[0114] The binder may be, for example, an acrylic resin, a polyvinyl butyl resin, a polyvinyl acetal resin, or an ethyl cellulose resin. The binder may be added in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the barium titanate compound, for example, 3 to 30 parts by weight. When the binder is mixed within the above content range, the dispersibility of the dielectric slurry is excellent, and the amount of impurities contained in the manufactured dielectric layer can be reduced.

[0115] The plasticizer may be, for example, phthalate compounds such as dioctyl phthalate, benzyl butyl phthalate, dibutyl phthalate, dihexyl phthalate, di(2-ethylhexyl) phthalate, and di(2-ethylbutyl) phthalate; adipic acid compounds such as dihexyl adipic acid and di(2-ethylhexyl) adipic acid; glycol compounds such as ethylene glycol, diethylene glycol, and triethylene glycol; or glycol ester compounds such as triethylene glycol dibutyrate, triethylene glycol di(2-ethylbutyrate), and triethylene glycol di(2-ethylhexanoate). The plasticizer may be added in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the barium titanate compound, for example, 1 to 10 parts by weight. When the plasticizer is mixed within the above content range, the dispersibility of the dielectric slurry is excellent, and the amount of impurities contained in the manufactured dielectric layer can be reduced.

[0116] The solvent may be an aqueous solvent such as water; an alcohol solvent such as ethanol, methanol, benzyl alcohol, or methoxyethanol; a glycol solvent such as ethylene glycol or diethylene glycol; a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone; an ester solvent such as butyl acetate, ethyl acetate, carbitol acetate, or butyl carbitol acetate; an ether solvent such as methyl cellosolve, ethyl cellosolve, butyl ether, or tetrahydrofuran; or an aromatic solvent such as benzene, toluene, or xylene. The solvent can be an alcohol or an aromatic solvent, for example, considering the solubility and dispersibility of the various additives contained in the dielectric slurry. The solvent may be mixed in an amount of 50 to 1000 parts by weight per 100 parts by weight of the barium titanate compound, or for example, 100 to 500 parts by weight. When the solvent is mixed within the above content range, the dielectric slurry components can be thoroughly mixed, and subsequent removal of the solvent is also easy.

[0117] The aforementioned dielectric slurry can be mixed using a wet ball mill or a stirring mill. When using zirconia balls in a wet ball mill, a large number of zirconia balls with diameters of 0.1 mm to 10 mm can be used for wet mixing for 8 to 48 hours, or 10 to 24 hours.

[0118] The manufactured dielectric slurry is formed into a dielectric layer after firing.

[0119] Methods for forming the manufactured dielectric slurry into a sheet shape include tape molding methods such as the doctor blade method and the calender roll method, or, for example, an on-roll molding coater with a head discharge system. A dielectric green sheet can then be obtained by drying the molded body.

[0120] A conductive paste layer is formed on the surface of a dielectric green sheet by applying a conductive paste in a predetermined pattern using various printing methods such as screen printing or transfer methods.

[0121] Next, a dielectric green sheet laminate is manufactured by stacking multiple dielectric green sheets with internal electrode patterns formed on them in layers, and then pressing them in the stacking direction. At this time, dielectric green sheets and internal electrode layer patterns can be stacked such that dielectric green sheets are positioned on the upper and lower surfaces of the dielectric green sheet laminate in the stacking direction.

[0122] The step of cutting the manufactured dielectric green sheet laminate to a predetermined size by dicing or other means can be selectively performed.

[0123] Furthermore, the dielectric green sheet laminate can be solidified and dried to remove plasticizers and other substances as needed, and after solidification and drying, it can be barrel polished using a horizontal centrifugal barrel polishing machine or the like. In barrel polishing, the dielectric green sheet laminate is placed in a barrel container along with media and polishing fluid, and rotational motion or vibration is applied to the barrel container to polish away unnecessary parts such as burrs generated during cutting. After barrel polishing, the dielectric green sheet laminate may be washed with a cleaning solution such as water and then dried.

[0124] Next, the dielectric green sheet laminate can be debindered (calcined) and fired to manufacture a capacitor body.

[0125] The debinding treatment conditions can be appropriately adjusted depending on the composition of the dielectric layer and the internal electrode layer. For example, the heating rate during debinding may be 5°C / hour to 300°C / hour, the support temperature may be 180°C to 400°C, and the temperature maintenance time may be 0.5 hours to 24 hours. The atmosphere during debinding may be air or a reducing atmosphere.

[0126] The firing conditions can be appropriately adjusted depending on the main component composition of the dielectric layer and the main component composition of the internal electrode layer. For example, firing may be carried out at a temperature of 1100°C to 1400°C, or for example, at a temperature of 1200°C to 1350°C. Furthermore, firing may be carried out for 0.5 hours to 8 hours, for example, 1 hour to 3 hours. Also, firing may be carried out in a reducing atmosphere, for example, a humidified atmosphere of a mixed gas of nitrogen and hydrogen, for example, under conditions of a hydrogen concentration of 1.0% or less. If the internal electrode layer contains nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere should be 1.0 × 10⁻⁶ -14 MPa or 1.0 × 10 -10 MPa is also acceptable.

[0127] After firing, annealing can be performed as needed. Annealing is a process to re-oxidize the dielectric layer, and it can be performed when firing is carried out in a reducing atmosphere. The conditions for the annealing process can also be appropriately adjusted depending on the composition of the dielectric layer. For example, the temperature during annealing may be 950°C to 1150°C, the time may be 0 to 20 hours, and the heating rate may be 50°C / hour to 500°C / hour. The annealing atmosphere may be a humidified nitrogen gas (N2) atmosphere, and the oxygen partial pressure may be 1.0 × 10⁻⁶ -9 MPa or 1.0 × 10 -5 MPa is also acceptable.

[0128] For humidifying nitrogen gas or mixed gases during debinding, calcination, or annealing, a wetter, for example, can be used, and in this case, the water temperature may be between 5°C and 75°C. Debinding, calcination, and annealing can be performed continuously or independently.

[0129] Selectively, the third and fourth surfaces of the manufactured capacitor body 110 can be subjected to surface treatments such as sand-frusting, laser irradiation, and barrel polishing. By performing such surface treatments, the edges of the first and second internal electrode layers may be exposed on the outermost surfaces of the third and fourth surfaces, thereby improving the electrical connection between the first and second external electrodes and the first and second internal electrode layers, and facilitating the formation of alloy parts.

[0130] Next, an external electrode is formed on one surface of the manufactured capacitor body 110.

[0131] As an example, a sintered metal layer can be formed by applying a paste for forming a sintered metal layer to an external electrode and then sintering it.

[0132] The paste for forming a sintered metal layer may contain conductive metals and glass. The explanation of conductive metals and glass is the same as described above, so a repeated explanation will be omitted. The paste for forming a sintered metal layer may also selectively contain binders, solvents, dispersants, plasticizers, oxide powders, etc. Binders can be, for example, ethyl cellulose, acrylic, butyral, etc., and solvents can be organic solvents or aqueous solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, toluene, etc.

[0133] Methods for applying the sintered metal layer-forming paste to the outer surface of the capacitor body 110 include various printing methods such as dipping and screen printing, application methods using dispensers, and spraying methods using sprayers. The sintered metal layer-forming paste is applied to at least the third and fourth surfaces of the capacitor body 110, and may also be applied to a portion of the first, second, fifth, or sixth surfaces where the band portions of the first and second external electrodes are selectively formed.

[0134] Subsequently, the capacitor body 110 coated with the paste for forming a sintered metal layer is dried and sintered at a temperature of 700°C to 1000°C for 0.1 to 3 hours to form a sintered metal layer.

[0135] A conductive resin layer can be selectively formed by applying a conductive resin layer-forming paste to the outer surface of the obtained capacitor body 110 and then curing it.

[0136] The paste for forming a conductive resin layer may contain a resin and, selectively, a conductive metal or a non-conductive filler. The explanations of conductive metals and resins are the same as those described above, so a repetition is omitted. The paste for forming a conductive resin layer may also selectively contain a binder, solvent, dispersant, plasticizer, oxide powder, etc. Binders can be, for example, ethyl cellulose, acrylic, butyral, etc., and solvents can be organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, toluene, or aqueous solvents.

[0137] As an example, the conductive resin layer can be formed by dipping the capacitor body 110 into a conductive resin layer forming paste and then curing it, printing the conductive resin layer forming paste onto the surface of the capacitor body 110 using screen printing or gravure printing, or applying the conductive resin layer forming paste to the surface of the capacitor body 110 and then curing it.

[0138] Next, a plating layer is formed on the outside of the conductive resin layer.

[0139] For example, the plating layer may be formed by a plating method, or by sputtering or electroplating (electric deposition).

[0140] The embodiments described above will be explained in more detail below through the examples. However, the following examples are for illustrative purposes only and do not limit the scope of rights.

[0141] (Manufacturing of multilayer ceramic capacitors) <Example 1> A first conductive paste was prepared by mixing nickel (Ni) and germanium oxide (GeO2). In this mixture, the GeO2 content was 0.72 parts by weight of Ge for every 100 parts by weight of Ni.

[0142] Furthermore, a second conductive paste was prepared by mixing nickel (Ni) and tin oxide (SnO2). In this mixture, the SnO2 content was 0.52 parts by weight of Sn per 100 parts by weight of Ni.

[0143] Next, a dielectric slurry was prepared using barium titanate (BaTiO3) powder. The dielectric slurry was produced by mechanical milling after adding zirconia balls (ZrO2 balls) as a dispersion medium, along with ethanol / toluene, a dispersant, and a binder.

[0144] Next, dielectric green sheets were manufactured using a head-dispensing on-roll molding coater with the manufactured dielectric slurry. The first conductive paste manufactured was printed onto the surface of the dielectric green sheet to form a first conductive paste layer, and the second conductive paste manufactured was printed onto the surface of another dielectric green sheet to form a second conductive paste layer. Dielectric green sheet laminates were manufactured by alternately stacking and pressing the dielectric green sheets with the first conductive paste layer and the dielectric green sheets with the second conductive paste layer.

[0145] The dielectric green sheet laminate was subjected to a calcination process at a temperature of 400°C or lower and in a nitrogen atmosphere, followed by firing at a firing temperature of 1300°C or lower and a hydrogen concentration of 1.0%H2 or lower.

[0146] Next, multilayer ceramic capacitors were manufactured through processes such as external electrode assembly and plating.

[0147] <Example 2> A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that a first conductive paste was prepared by mixing GeO2 with Ni at a content of 1.21 parts by weight of Ge per 100 parts by weight of Ni, and a second conductive paste was prepared by mixing SnO2 with Ni at a content of 0.44 parts by weight of Sn per 100 parts by weight of Ni.

[0148] <Example 3> A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that a first conductive paste was prepared by mixing GeO2 with Ni at a content of 0.89 parts by weight, and a second conductive paste was prepared by mixing SnO2 with Ni at a content of 0.79 parts by weight, except that a second conductive paste was prepared by mixing SnO2 with Ni at a content of 0.79 parts by weight, except that a multilayer ceramic capacitor was manufactured in the same manner as in Example 1.

[0149] <Example 4> A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that a first conductive paste was prepared by mixing GeO2 with Ni at a content of 1.1 parts by weight of Ge per 100 parts by weight of Ni, and a second conductive paste was prepared by mixing SnO2 with Ni at a content of 1.2 parts by weight of Sn per 100 parts by weight of Ni.

[0150] <Comparative Example 1> A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that both the first conductive paste and the second conductive paste were made from Ni alone.

[0151] <Comparative Example 2> A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that both the first conductive paste and the second conductive paste were prepared by mixing Ni and GeO2. In this case, the GeO2 was mixed in an amount of 1.25 parts by weight of Ge per 100 parts by weight of Ni.

[0152] <Comparative Example 3> A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that both the first conductive paste and the second conductive paste were prepared by mixing Ni and SnO2. In this case, the SnO2 was mixed in a ratio of 0.95 parts by weight of Sn to 100 parts by weight of Ni.

[0153] <Evaluation 1: SEM-EDS line analysis> SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis was performed on the multilayer ceramic capacitors manufactured in Examples 1 to 4 and Comparative Examples 1 to 3, and the results are shown in Table 1 and Figure 6 below.

[0154] Specifically, the multilayer ceramic capacitor manufactured in Example 1 was cured in an epoxy mixture. Then, the L-axis and T-axis surfaces (LT surfaces) of the capacitor body were polished to a depth of 1 / 2 in the W-axis direction. After fixing, the capacitor was maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample that allowed observation of the active region where the dielectric layer and the internal electrode layer intersected. Next, the active region of the cross-sectional sample was measured using a scanning electron microscope (SEM). The SEM was measured in an area of ​​approximately 8 μm × 8 μm where six dielectric layers and six internal electrode layers were visible in the active region, under conditions of an acceleration voltage of 2.0 kV. Next, energy-dispersive spectroscopy (EDS) analysis was performed on the first and second internal electrode layers through the SEM image of the measured cross-sectional sample to confirm the components and their content in the first and second internal electrode layers. Specifically, when the active region of the cross-sectional sample was divided into three equal parts—upper, middle, and lower—three points were taken in the first internal electrode layer and three points in the second internal electrode layer for each region. The average component content was then calculated for a total of nine points in both the first and second internal electrode layers.

[0155] Figure 6 shows SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis images of the first internal electrode layer and the second internal electrode layer according to Example 1.

[0156] Referring to Figure 6, it can be seen that in Example 1, nickel (Ni) and germanium (Ge) are present in the first internal electrode layer, and nickel (Ni) and tin (Sn) are present in the second internal electrode layer.

[0157] In Table 1 below, the Ge content is shown based on 100 parts by weight of Ni in the first or second internal electrode layer, and the Sn content is shown based on 100 parts by weight of Ni in the first or second internal electrode layer.

[0158] [Table 1]

[0159] From Table 1 and Figure 7 above, it can be seen that the multilayer ceramic capacitor according to one embodiment includes first and second internal electrode layers with different compositions.

[0160] <Rating 2: Reliability> The accelerated lifetime reliability (MTTF) of the multilayer ceramic capacitors manufactured in Examples 1 to 4 and Comparative Examples 1 to 3 was measured using the method described below, and the results are shown in Table 2.

[0161] MTTF (mean time to failure) was measured by determining the mean time to failure (hr) under conditions of 125°C, 8V voltage, and 72 hours.

[0162] In Table 2 below, the MTTF values ​​are shown as ratios based on the results of Comparative Example 1.

[0163] <Evaluation 3: Degree of Degradation of Interfacial Potential Barrier> Kelvin probe force microscope (KPFM) analysis was performed on the multilayer ceramic capacitors manufactured in Examples 1 to 4 and Comparative Examples 1 to 3 to evaluate the degree of degradation of the interfacial potential barrier between the dielectric layer and the internal electrode layer. The results are shown in Table 2 below.

[0164] Specifically, to measure the change in the interfacial potential barrier before and after accelerated lifetime reliability (MTTF) evaluation, samples of multilayer ceramic capacitors manufactured in Examples 1 to 4 and Comparative Examples 1 to 3 were prepared, along with samples before degradation, by degrading them under MTTF evaluation conditions of 125°C, 8V, and 72 hours. The prepared multilayer ceramic capacitor samples were prepared by polishing the L-axis and T-axis surfaces (LT surfaces) of the capacitor body to a depth of 1 / 2 in the W-axis direction, exposing the LT cross-section. Next, KPFM (Kelvin probe force microscope) analysis was performed on the central part of the active region of the cross-sectional sample. KPFM analysis was performed using a Park Systems NX-10 system, measuring an area of ​​approximately 5 μm × 5 μm at an applied voltage of 1 V. The degree of degradation of the interfacial potential barrier was calculated by differentiating the surface potential (V) value obtained from the KPFM analysis in the x-direction.

[0165] [Table 2]

[0166] Table 2 shows that in Examples 1 to 4, the degree of degradation of the interfacial potential barrier between the dielectric layer and the internal electrode layer is lower and reliability is superior compared to Comparative Examples 1 to 3. From this, it can be seen that, according to one embodiment, when the first internal electrode layer and the second internal electrode layer contain different elements, a multilayer ceramic capacitor with improved reliability can be obtained by preventing the degradation of the interfacial potential barrier.

[0167] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, description of the invention, and attached drawings, and these also naturally fall within the scope of the present invention. [Explanation of Symbols]

[0168] 100: Multilayer ceramic capacitor 110: Capacitor body 111: Dielectric layer 121: First internal electrode layer 122: Second inner electrode layer 131: First external electrode 132: Second external electrode

Claims

1. A capacitor body including a dielectric layer and an internal electrode layer, and Includes external electrodes positioned outside the capacitor body, The internal electrode layer includes a first internal electrode layer and a second internal electrode layer that are stacked spaced apart from each other with the dielectric layer in between. A multilayer ceramic capacitor in which the first internal electrode layer and the second internal electrode layer contain one or more elements selected from aluminum (Al), silicon (Si), germanium (Ge), zinc (Zn), tin (Sn), indium (In), and iron (Fe), and the first internal electrode layer and the second internal electrode layer contain different elements from each other.

2. The first internal electrode layer comprises one or more elements (X1) selected from aluminum (Al), silicon (Si), and germanium (Ge). The multilayer ceramic capacitor according to claim 1, wherein the second internal electrode layer comprises one or more elements (X2) selected from zinc (Zn), tin (Sn), indium (In), and iron (Fe).

3. The first internal electrode layer is given a cathode potential. The multilayer ceramic capacitor according to claim 2, wherein an anode potential is applied to the second internal electrode layer.

4. The multilayer ceramic capacitor according to claim 2, wherein the first internal electrode layer and the second internal electrode layer further contain nickel (Ni).

5. The first internal electrode layer comprises nickel (Ni) and germanium (Ge), The multilayer ceramic capacitor according to claim 4, wherein the second internal electrode layer comprises nickel (Ni) and tin (Sn).

6. The multilayer ceramic capacitor according to claim 4, wherein the element (X1) of the first internal electrode layer is contained in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni).

7. The multilayer ceramic capacitor according to claim 4, wherein the element (X2) of the second internal electrode layer is contained in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni).

8. The multilayer ceramic capacitor according to claim 2, wherein in the first internal electrode layer, the content of the element (X1) is higher at the interface between the first internal electrode layer and the dielectric layer than in the central region of the first internal electrode layer in the stacking direction.

9. The multilayer ceramic capacitor according to claim 8, wherein the element (X1) of the first internal electrode layer is present in oxide form at the interface with the dielectric layer.

10. The multilayer ceramic capacitor according to claim 2, wherein the second internal electrode layer has a higher content of the element (X2) at the interface between the second internal electrode layer and the dielectric layer than in the central region of the second internal electrode layer in the stacking direction.

11. The multilayer ceramic capacitor according to claim 10, wherein the element (X2) of the second internal electrode layer is present in oxide form at the interface with the dielectric layer.

12. A step of manufacturing a dielectric green sheet using a dielectric slurry; The steps of: printing a first conductive paste on the surface of the dielectric green sheet to form a first conductive paste layer; and printing a second conductive paste on the surface of the dielectric green sheet to form a second conductive paste layer; A step of manufacturing a dielectric green sheet laminate by alternately stacking dielectric green sheets on which the first conductive paste layer is formed and dielectric green sheets on which the second conductive paste layer is formed; A step of firing the dielectric green sheet laminate to manufacture a capacitor body including a dielectric layer and an internal electrode layer; and The step includes forming an external electrode on the outside of the capacitor body, The internal electrode layer includes a first internal electrode layer and a second internal electrode layer that are stacked spaced apart from each other with the dielectric layer in between. A method for manufacturing a multilayer ceramic capacitor, wherein the first conductive paste and the second conductive paste are manufactured from raw materials containing one or more metals selected from Al, Si, Ge, Zn, Sn, In, and Fe, an alloy of the metal and Ni, or an oxide of the metal, and the first conductive paste and the second conductive paste are manufactured from different raw materials.

13. The first conductive paste is manufactured from raw materials containing one or more metals (M1) selected from Al, Si, and Ge, an alloy of the metal (M1) and Ni, or an oxide of the metal (M1). The method for manufacturing a multilayer ceramic capacitor according to claim 12, wherein the second conductive paste is manufactured from a raw material comprising one or more metals (M2) selected from Zn, Sn, In, and Fe, an alloy of the metal (M2) and Ni, or an oxide of the metal (M2).

14. The method for manufacturing a multilayer ceramic capacitor according to claim 13, wherein the first conductive paste and the second conductive paste are manufactured further containing nickel (Ni).

15. The method for manufacturing a multilayer ceramic capacitor according to claim 13, wherein the raw materials for the first conductive paste contain the metal (M1) in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni).

16. The method for manufacturing a multilayer ceramic capacitor according to claim 13, wherein the raw materials for the second conductive paste contain the metal (M2) in an amount of 0.1 to 8 parts by weight per 100 parts by weight of nickel (Ni).

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