Multilayer ceramic capacitor and method for manufacturing the same

Abstract

This invention provides a multilayer ceramic capacitor with excellent durability and moisture resistance, as well as a method for manufacturing the same. [Solution] The multilayer ceramic capacitor according to the embodiment includes a capacitor body comprising 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 comprises nickel (Ni), and the spatial lattice edge length of the nickel (Ni) obtained from the following formula 1 through X-ray diffraction analysis (XRD) of the internal electrode layer is 3.522 Å to 3.544 Å. JPEG2026052635000011.jpg25170 (In formula 1 above, λ, h, k, l, and θ are as defined in the specification.)

Description

[Technical Field]

[0001] This disclosure relates to a multilayer ceramic capacitor and a method for manufacturing the same. [Background technology]

[0002] Electronic components that use ceramic materials include capacitors, inductors, piezoelectric elements, varistors, and thermistors. Among these ceramic electronic components, multilayer ceramic capacitors (MLCCs) can be used in a wide variety of electronic devices due to their advantages of being small, yet guaranteeing high capacitance and being easy to mount.

[0003] For example, multilayer ceramic capacitors (MLCCs) can be used as chip-type capacitors mounted on substrates of various electronic products such as liquid crystal displays (LCDs), plasma display panels (PDPs), organic light-emitting diodes (OLEDs), computers, personal portable devices, and smartphones, playing a role in charging or discharging electricity.

[0004] Recently, the demand for miniaturization and increased capacitance in MLCCs requires an increase in the number of layers of dielectric and internal electrodes. An increase in the number of layers leads to an increase in the electric field strength transmitted per dielectric layer and a rise in heat generation, which causes problems with durability and reliability. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] One embodiment provides a multilayer ceramic capacitor with excellent durability and moisture resistance 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 outside the capacitor body, wherein the internal electrode layer comprises nickel (Ni), and the spatial lattice edge length of the nickel (Ni), obtained from the following formula 1 through X-ray diffraction analysis (XRD) of the internal electrode layer, is 3.522 Å to 3.544 Å.

[0008]

number

[0009] In the above formula 1, λ is Cu K α This is 1.5406 Å, where h, k, and l are surface indices and θ is the Bragg angle.

[0010] The dielectric layer may contain a barium titanate-based compound.

[0011] The difference between the spatial lattice side length of the nickel (Ni) and the spatial lattice side length of the barium titanate compound may be 0.492 Å to 0.515 Å, and the spatial lattice side length of the barium titanate compound can be obtained from Equation 1 through X-ray diffraction analysis (XRD) of the dielectric layer.

[0012] The internal electrode layer may further contain germanium (Ge).

[0013] The germanium (Ge) is dissolved in the nickel (Ni).

[0014] The germanium (Ge) may be present in the internal electrode layer in an amount of 0.95 atomic% to 11.95 atomic% relative to the total amount of nickel (Ni) and germanium (Ge).

[0015] The internal electrode layer may further include one or more selected from copper (Cu), silver (Ag), palladium (Pd), gold (Au), and alloys thereof.

[0016] The dielectric layer may contain germanium (Ge).

[0017] The average thickness of the internal electrode layer may be 0.1 μm to 1 μm.

[0018] The average thickness of the dielectric layer may be 0.1 μm to 8.0 μm.

[0019] Another embodiment provides a method for manufacturing a multilayer ceramic capacitor, comprising the steps of: mixing nickel (Ni) and germanium (Ge)-based raw materials to produce a conductive paste; producing a dielectric green sheet using a dielectric slurry; printing the conductive paste onto the surface of the dielectric green sheet to form a conductive paste layer; stacking the dielectric green sheets on which the conductive paste layer is formed to produce a dielectric green sheet laminate; firing the dielectric green sheet laminate to produce 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 contains nickel (Ni), and the spatial lattice edge length of the nickel (Ni) obtained from Equation 1 through X-ray diffraction analysis (XRD) of the internal electrode layer is 3.522 Å to 3.544 Å.

[0020] The germanium (Ge)-based raw material may be Ge, an oxide of Ge, a nitride of Ge, a salt compound of Ge, or a compound in the form of a sol in which Ge is dispersed in an organic solvent.

[0021] The germanium (Ge)-based raw material may be included in an amount such that Ge is 0.95 atomic% to 11.95 atomic% relative to the total amount of nickel (Ni) and the germanium (Ge)-based raw material.

[0022] Another embodiment includes the steps of manufacturing a conductive paste containing nickel (Ni), manufacturing a dielectric slurry containing a barium titanate-based compound containing barium (Ba), titanium (Ti), and germanium (Ge), manufacturing a dielectric green sheet using the dielectric slurry, printing the conductive paste on the surface of the dielectric green sheet to form a conductive paste layer, laminating the dielectric green sheets with the conductive paste layer formed thereon 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. The internal electrode layer contains nickel (Ni), and provides a method for manufacturing a multilayer ceramic capacitor in which the lattice edge length of nickel (Ni) obtained from the above formula 1 is 3.522 Å to 3.544 Å through X-ray diffraction analysis (XRD) of the internal electrode layer.

Advantages of the Invention

[0023] The multilayer ceramic capacitor according to one embodiment has reduced crack generation, improved durability, and excellent moisture resistance reliability.

Brief Description of the Drawings

[0024] [Figure 1] It is a perspective view showing a multilayer ceramic capacitor according to one embodiment. [Figure 2] It is a cross-sectional view of the multilayer ceramic capacitor cut along the line I-I' of FIG. 1. [Figure 3] It is a cross-sectional view of the multilayer ceramic capacitor cut along the line II-II' of FIG. 1. [Figure 4] It is a separated perspective view showing the laminated structure of the internal electrode layer in the capacitor body of FIG. 1. [Figure 5] It is an XRD (X-ray diffraction analysis) graph of the internal electrode layer manufactured after firing according to Example 3 and the raw material powder for forming the internal electrode layer before firing. [Figure 6]This graph shows a magnified view of the Ni(220) portion in the XRD results for the internal electrode layer manufactured after firing according to Example 3 and the raw material powder for forming the internal electrode layer before firing. [Figure 7] This is a SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis diagram of the internal electrode layer according to Example 3. [Modes for carrying out the invention]

[0025] Embodiments of the present invention will be described in detail below 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 order to clearly illustrate the present invention, unnecessary parts have been omitted from the drawings, and the same or similar components are denoted by the same reference numerals throughout the specification. Furthermore, 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.

[0026] The accompanying drawings are provided solely to facilitate understanding of the embodiments disclosed herein, and it should be understood that the accompanying drawings do not limit the technical ideas disclosed herein and include all modifications, equivalents, or substitutions that fall within the concept and scope of the invention.

[0027] 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.

[0028] Furthermore, when a part such as a layer, membrane, region, or plate is said to be "on top of" or "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Also, being "on top of" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on top of" or "above" the opposite side of gravity.

[0029] Throughout the specification, terms such as “includes” or “have” are intended to specify the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the presence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof. Therefore, when a part “includes” a component, this means that it may include other components rather than excluding them, unless otherwise stated.

[0030] Furthermore, throughout the specification, "on a plane" refers to the view of the subject from above, and "on a cross-section" refers to the view of a cross-section obtained by cutting the subject perpendicularly, viewed from the side.

[0031] Furthermore, throughout the specification, the term "connected" does not only mean that two or more components are directly connected, but can 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 despite being referred to by different names depending on their position or function.

[0032] A multilayer ceramic capacitor according to one embodiment will be described below with reference to Figures 1 to 4.

[0033] 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.

[0034] 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 can be used as the same concept as the stacking direction in which the dielectric layer 111 is stacked, for example. The length direction (L-axis direction) extends parallel to the broad surface (main surface) of the sheet-shaped component and may be roughly perpendicular to the thickness direction (T-axis direction), for example, the 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) extends parallel to the broad surface (main surface) of the sheet-shaped component and may be roughly 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).

[0035] 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 positioned outside the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 positioned at opposite ends of the capacitor body 110 in the longitudinal direction (L-axis direction).

[0036] The capacitor body 110 may, for example, have a roughly hexahedral shape.

[0037] For the convenience of describing 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 and connected to the third and fourth surfaces that face each other in the width direction (W-axis direction) are defined as the fifth and sixth surfaces.

[0038] 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.

[0039] The shape, dimensions, and number of dielectric layers 111 of the capacitor body 110 are not limited to those shown in the drawings of this embodiment.

[0040] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrode layers 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and first internal electrode layers 121 and second internal electrode layers 122 that are alternately arranged in the thickness direction (T-axis direction) with the dielectric layers 111 in between.

[0041] At this time, the boundaries between adjacent dielectric layers 111 of the capacitor body 110 can become so integrated that they are difficult to confirm without using a scanning electron microscope (SEM).

[0042] The capacitor body 110 may include an active region and cover regions 112, 113.

[0043] 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 capacitance in 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.

[0044] The cover regions 112 and 113 are thickness-direction margins and can be arranged 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.

[0045] Furthermore, the capacitor body 110 may also include a side margin region.

[0046] 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 is formed when applying a conductive paste layer for the internal electrode layer to the surface of the dielectric green sheet, by applying the conductive paste layer only to a portion of the surface of the dielectric green sheet, and stacking dielectric green sheets without the conductive paste layer on both sides of the dielectric green sheet surface, and then firing, but the formation method is not limited to this.

[0047] 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.

[0048] The internal electrode layer, dielectric layer, and external electrode will be explained in detail below.

[0049] [Internal electrode layer] The internal electrode layers 121 and 122, namely 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 exposed through the third and fourth surfaces of the capacitor body 110.

[0050] 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.

[0051] 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.

[0052] In one embodiment, the first internal electrode layer 121 and the second internal electrode layer 122 may contain nickel (Ni) as the conductive metal.

[0053] The spatial lattice side length of nickel (Ni) can be obtained from the results of X-ray diffraction (XRD) analysis of the internal electrode layers 121 and 122 containing nickel (Ni) using Bragg's law. In other words, the spatial lattice side length of nickel (Ni) in one embodiment can be obtained from the Ni peak that appears in the XRD results of the internal electrode layer in one embodiment using Bragg's law.

[0054] Specifically, the Bragg angle θ can be obtained using the position 2θ of the Ni peak appearing on the XRD graph for the internal electrode layer according to one embodiment, and the interplane distance can be calculated using the Bragg angle to determine the spatial lattice edge length of Ni.

[0055] According to one embodiment, the spatial lattice edge length of nickel (Ni) obtained from the following formula 1 may be 3.522 Å to 3.544 Å, for example, 3.523 Å to 3.543 Å, 3.524 Å to 3.542 Å, or 3.525 Å to 3.541 Å. When the spatial lattice edge length of nickel (Ni) in the internal electrode layer according to one embodiment is within the above range, the displacement difference between the dielectric layer and the barium titanate-based compound at the interface between the internal electrode layer and the dielectric layer is reduced, thereby reducing crack occurrence in the multilayer ceramic capacitor, including the active region, cover region, and side margin region. Specifically, crack occurrence at the interface between the internal electrode layer and the dielectric layer in the active region can be reduced. Therefore, not only is the durability of the multilayer ceramic capacitor improved, but it can also have excellent moisture resistance reliability.

[0056]

number

[0057] In equation 1, λ is Cu K α This is 1.5406 Å, where h, k, and l are surface indices and θ is the Bragg angle.

[0058] Specifically, after curing the multilayer ceramic capacitor 100 in an epoxy mixture, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body 110 are polished to half a depth in the L-axis direction. After fixing, the capacitor 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, Cu K is applied to the internal electrode layers 121 and 122 in the active region of the cross-sectional sample. αBy measuring X-ray diffraction (XRD) using a line, the spatial lattice edge length of nickel (Ni) can be calculated from the results using Bragg's law. For example, the spatial lattice edge length of nickel (Ni) can be obtained by dividing the active region of a cross-sectional sample into three equal parts: upper, middle, and lower. Three points within the internal electrode layer are then specified for each region, and the average value of these nine points is obtained.

[0059] In one embodiment, the first internal electrode layer 121 and the second internal electrode layer 122 may further contain germanium (Ge). By including germanium (Ge) together with nickel (Ni) in the internal electrode layer, an increase in the spatial lattice edge length of Ni can be induced, thereby reducing the displacement difference between the Ni in the internal electrode layer and the barium titanate compound in the dielectric layer at the interface between the internal electrode layer and the dielectric layer.

[0060] Specifically, germanium (Ge) may be included in the internal electrode layers 121 and 122 in a form that is solid-dissolved within nickel (Ni).

[0061] In one embodiment, the XRD results for the internal electrode layer do not show a single peak for germanium (Ge).

[0062] In other words, according to one embodiment, the spatial lattice edge lengths of nickel (Ni) obtained from the results of X-ray diffraction analysis (XRD) of the internal electrode layers 121 and 122 differ from the spatial lattice edge lengths of Ni alone in a typical simple cubic structure, and can specifically have increased edge lengths compared to the latter, due to the solid solution of Ge within the Ni lattice.

[0063] Generally, multilayer ceramic capacitors consist of internal electrode layers and dielectric layers made of different materials. Specifically, the internal electrode layer is mainly composed of Ni, and the dielectric layer is mainly composed of BaTiO3. The space lattice of BaTiO3 transitions to a tetragonal structure below approximately 130°C, which creates a difference in space lattice edge length compared to the simple cubic structure of Ni. The edge length of the space lattice of a typical simple cubic structure (a=b=c) of Ni is approximately 3.520 Å, while in the case of a tetragonal structure (a=b≠c) of BaTiO3, the horizontal and vertical edge lengths are approximately 3.995 Å, and the height is approximately 4.036 Å. In other words, a space lattice displacement difference of up to 0.516 Å occurs between Ni and BaTiO3.

[0064] Such displacement differences complicate the interatomic bonding between the dielectric layer and the internal electrode layer, causing electric field concentration at the laminate interface, i.e., the interface between the dielectric layer and the internal electrode layer, which weakens moisture resistance reliability. Furthermore, interatomic mismatch interfaces between the dielectric layer and the internal electrode layer can also lead to crack formation.

[0065] According to one embodiment, the spatial lattice side length of nickel (Ni) obtained from the XRD results for the internal electrode layers 121 and 122 according to one embodiment is longer than the spatial lattice side length of typical Ni, thereby reducing the displacement difference between the Ni in the internal electrode layer and the barium titanate compound in the dielectric layer at the interface between the internal electrode layer and the dielectric layer. As a result, crack initiation in the multilayer ceramic capacitor, specifically at the interface between the internal electrode layer and the dielectric layer, is minimized, improving durability and providing excellent moisture resistance reliability.

[0066] As an example, the difference between the spatial lattice side lengths of nickel (Ni) in the internal electrode layers 121 and 122 and the spatial lattice side lengths of the barium titanate compound in the dielectric layer, i.e., the displacement difference, may be 0.492 Å to 0.515 Å, for example, 0.493 Å to 0.514 Å, 0.494 Å to 0.513 Å, or 0.495 Å to 0.512 Å. The spatial lattice side lengths of the barium titanate compound are obtained from Equation 1 through X-ray diffraction analysis (XRD) of the dielectric layer 111. When the displacement difference between nickel (Ni) and the barium titanate compound is within the above range, crack initiation in the multilayer ceramic capacitor, specifically at the interface between the internal electrode layer and the dielectric layer, is minimized, improving durability and providing excellent moisture resistance reliability.

[0067] Germanium (Ge) may be present in the internal electrode layers 121 and 122 in an amount of 0.95 atomic% to 11.95 atomic% relative to the total amount of nickel (Ni) and germanium (Ge), for example, in amounts of 0.98 atomic% to 11.5 atomic%, 1.0 atomic% to 11.0 atomic%, 1.3 atomic% to 10.5 atomic%, or 1.5 atomic% to 10.0 atomic%. When germanium (Ge) is present in the internal electrode layers within the above content range, it can induce an increase in the spatial lattice edge length of Ni, thereby reducing the displacement difference between Ni in the internal electrode layer and the barium titanate-based compound in the dielectric layer at the interface between the internal electrode layer and the dielectric layer. This reduces crack formation in the multilayer ceramic capacitor, specifically at the interface between the internal electrode layer and the dielectric layer, improving durability and moisture resistance reliability.

[0068] The germanium (Ge) in the internal electrode layers 121 and 122 may originate from a substance added to the conductive paste during the formation of the internal electrode layers, or from some of the Ge contained in the composition of the dielectric layer that migrates to the internal electrode layers.

[0069] The first internal electrode layer 121 and the second internal electrode layer 122 may further contain, as conductive metals, one or more selected from copper (Cu), silver (Ag), palladium (Pd), gold (Au), and alloys thereof, in addition to nickel (Ni).

[0070] Furthermore, the first internal electrode layer 121 and the second internal electrode layer 122 may further contain dielectric particles of the same composition as the ceramic material contained in the dielectric layer 111.

[0071] The presence of nickel (Ni) and germanium (Ge) in the internal electrode layers 121 and 122 can be confirmed by SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis.

[0072] Specifically, after curing the multilayer ceramic capacitor 100 in an epoxy mixture, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body 110 are polished to a depth of 1 / 2 in the L-axis direction. After fixing, the capacitor 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 one dielectric layer and at least 1 to 10 internal electrode layers are visible in the active region. For example, the SEM can be used with a Thermofisher Scientific Verios G4 product at 10kV in an approximately 6μm × 6μm area where six dielectric layers and six internal electrode layers are visible in the active region. Then, energy-dispersive spectroscopy (EDS) analysis of the internal electrode layers can be performed through the SEM image of the measured cross-sectional sample to confirm the presence and content of Ni, Ge, etc., in the internal electrode layers 121 and 122. For example, the content of Ni, Ge, etc. according to one embodiment can be obtained by dividing the active region of the cross-sectional sample into three equal parts, upper, central, and lower, during the EDS point analysis, and then specifying three points within the internal electrode layer for each region, for a total of nine points, and taking the average value of these points.

[0073] The first internal electrode layer 121 and the second internal electrode layer 122 can be formed using a conductive paste containing a nickel (Ni) conductive metal and a germanium (Ge)-based raw material selectively. The conductive paste can be printed using screen printing or gravure printing.

[0074] 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, or for example, 0.1 μm to 1 μm. When the average thickness of the internal electrode layers 121 and 122 is within the above range, the reliability of the multilayer ceramic capacitor is excellent.

[0075] The average thickness of the first internal electrode layer 121 and the second internal electrode layer 122 can be measured by scanning electron microscope (SEM) analysis after the multilayer ceramic capacitor 100 has been cured in an epoxy mixture, polished, and then ion milled. For example, a Verios G4 product from Thermofisher Scientific can be used as the scanning electron microscope, with measurement conditions of 10kV and 0.2nA, and the analysis magnification may be 100x. The measurement can be performed so that at least one, three, five, or ten or more internal electrode layers 121 and 122 are shown. 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, using the center point in the length direction (L-axis direction) or width direction (W-axis direction) of the measured cross-sectional sample as the reference point. The spacing between the 10 points can be adjusted by the scanning electron microscope (SEM) image scale, for example, between 1 μm and 100 μm, 1 μm and 50 μm, or 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 spacing between the 10 points can be adjusted.

[0076] [Dielectric layer] In one embodiment, the dielectric layer 111 may mainly consist of a barium titanate-based compound containing barium (Ba) and titanium (Ti).

[0077] 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.

[0078] 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.

[0079] The dielectric layer 111 according to one embodiment may contain germanium (Ge). Specifically, the barium titanate-based compound may further contain germanium (Ge) in addition to barium (Ba) and titanium (Ti). For example, germanium (Ge) may be solid-dissolved in BaTiO3.

[0080] 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.

[0081] This is a scanning electron microscope (SEM) image of the cross-sectional sample measured as described above. The dielectric layer 111's center point in the length direction (L-axis direction) or width direction (W-axis direction) is used as the reference point, and the thickness can be determined by the arithmetic mean of the dielectric layer 111 thickness at 10 points located at predetermined intervals from the reference point. The interval between the 10 points can be adjusted by the scale of the scanning electron microscope (SEM) image, for example, between 1 μm and 100 μm, 1 μm and 50 μm, or 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.

[0082] 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.

[0083] [External electrode] External electrodes 131 and 132, namely the first external electrode 131 and the second external electrode 132, can be electrically connected to the exposed portions of the first internal electrode layer 121 and the second internal electrode layer 122 by applying voltages of different polarities to each other.

[0084] 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 are opposite each other. At this time, the capacitance of the multilayer ceramic capacitor 100 becomes proportional to the superimposed area of ​​the first internal electrode layer 121 and the second internal electrode layer 122, which are superimposed on each other along the T-axis in the active region.

[0085] The first external electrode 131 and the second external electrode 132 may each include a first connecting portion and a second connecting portion, which are arranged on the third and fourth surfaces of the capacitor body 110 and connected to the first internal electrode layer 121 and the second internal electrode layer 122, respectively, and a first band portion and a second band portion, which are arranged on the edges where the third and fourth surfaces of the capacitor body 110 meet the first and second surfaces or the fifth and sixth surfaces.

[0086] The first band portion and the second band portion extend from the first and second connection portions to a portion of the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110, respectively. The first band portion and the second band portion can serve to improve the adhesion strength of the first external electrode 131 and the second external electrode 132.

[0087] 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.

[0088] The sintered metal layer may contain conductive metals and glass.

[0089] 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.

[0090] 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).

[0091] Selectively, the conductive resin layer can be formed on top of the 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 do not have to include a sintered metal layer, in which case the conductive resin layer can be in direct contact with the capacitor body 110.

[0092] 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 where the conductive resin layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 (i.e., the band portion) may be longer than the length of the region where the sintered metal layer extends to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 (i.e., the band portion). In other words, the conductive resin layer can be formed on top of the sintered metal layer and can be formed in a manner that completely covers the sintered metal layer.

[0093] The conductive resin layer contains a resin and a conductive metal.

[0094] 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 form a paste. Examples include phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0095] 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.

[0096] The conductive metal contained in the conductive resin layer may be spherical, flake-shaped, or a combination thereof. That is, the conductive metal may consist only of flake-shaped elements, only of spherical elements, or a mixture of flake-shaped and spherical elements.

[0097] Here, spherical can include forms that are not perfectly spherical, for example, forms in which the ratio of the length of the major axis to the length of the minor axis (major axis / minor axis) is 1.45 or less. Flake powder means powder having a flat and elongated shape, and is not particularly limited, but for example, the ratio of the length of the major axis to the length of the minor axis (major axis / minor axis) may be 1.95 or more.

[0098] The first external electrode 131 and the second external electrode 132 may further include a plating layer disposed on the outside of the conductive resin layer.

[0099] 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. Furthermore, the plating layer may include multiple nickel (Ni) plating layers and / or multiple tin (Sn) plating layers.

[0100] 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).

[0101] [Manufacturing method for multilayer ceramic capacitors] The following describes a method for manufacturing a multilayer ceramic capacitor 100 according to one embodiment.

[0102] A multilayer ceramic capacitor 100 according to one embodiment can be manufactured by the following steps: manufacturing a conductive paste containing nickel (Ni); manufacturing a dielectric green sheet using a dielectric slurry and printing the conductive paste onto the surface of the dielectric green sheet to form a conductive paste layer; manufacturing a dielectric green sheet laminate by stacking the dielectric green sheets on which the conductive paste layer is formed; manufacturing a capacitor body including a dielectric layer and an internal electrode layer by firing the dielectric green sheet laminate; and forming external electrodes on the outside of the capacitor body.

[0103] A conductive paste for forming an internal electrode layer can be manufactured by mixing nickel (Ni) with germanium (Ge)-based raw materials. When using germanium (Ge)-based raw materials to form an internal electrode layer, it is possible to obtain Ni in a form in which Ge is solid-dissolved within the Ni lattice, and it is also possible to induce an increase in the spatial lattice edge length of the obtained Ni.

[0104] The germanium (Ge)-based raw material may be Ge, an oxide of Ge, a nitride of Ge, a salt compound of Ge, or a compound in the form of a sol in which Ge is dispersed in an organic solvent.

[0105] The germanium (Ge)-based raw material may be included in a content such that Ge is 0.95 atomic% to 11.95 atomic% relative to the total amount of nickel (Ni) and germanium (Ge)-based raw materials. For example, it may be included in a content such as 0.98 atomic% to 11.5 atomic%, 1.0 atomic% to 11.0 atomic%, 1.3 atomic% to 10.5 atomic%, or 1.5 atomic% to 10.0 atomic%. When the germanium (Ge)-based raw material is mixed within the above content range, it is possible to induce an increase in the spatial lattice edge length of Ni in the internal electrode layer, thereby reducing the displacement difference between Ni in the internal electrode layer and the barium titanate-based compound in the dielectric layer at the interface between the internal electrode layer and the dielectric layer. This minimizes crack initiation and makes it possible to obtain a multilayer ceramic capacitor with excellent durability and moisture resistance reliability.

[0106] Conductive paste can be manufactured by further mixing one or more conductive metals selected from copper (Cu), silver (Ag), palladium (Pd), gold (Au), and alloys thereof, in addition to nickel (Ni).

[0107] Furthermore, the conductive paste can be manufactured by additionally mixing in a binder and a solvent. Additionally, barium titanate powder may be mixed in as a co-material if necessary. The co-material can suppress the sintering of the conductive powder during the firing process.

[0108] Dielectric slurry can be manufactured by selectively mixing a barium titanate-based compound, which is the main component powder, with a secondary component powder.

[0109] Barium titanate compounds may contain barium (Ba), titanium (Ti), and selectively germanium (Ge).

[0110] The auxiliary powder may include compounds containing rare earth elements, transition metal elements, etc. The auxiliary powder may be, for example, oxides, nitrides, salt compounds of rare earth elements, transition metal elements, etc., or compounds in sol form dispersed in an organic solvent.

[0111] Dielectric slurry can be manufactured by additionally mixing solvents with additives such as dispersants, binders, plasticizers, lubricants, and antistatic agents.

[0112] The dispersant may include, for example, at least one selected from 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 per 100 parts by weight of the barium titanate compound, or for example, 0.3 to 3 parts by weight. 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.

[0113] The binder may be, for example, an acrylic resin, a polyvinyl butyral resin, a polyvinyl acetal resin, or an ethylcellulose 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.

[0114] 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.

[0115] 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. For example, an alcohol solvent or an aromatic solvent can be used, taking into consideration 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 the solvent can be easily removed thereafter.

[0116] 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 from 0.1 mm to 10 mm can be used for wet mixing for 8 to 48 hours, or 10 to 24 hours.

[0117] The manufactured dielectric slurry is formed as a dielectric layer after firing.

[0118] 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.

[0119] 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.

[0120] 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, the 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.

[0121] The manufacturing dielectric green sheet laminate can be selectively cut to predetermined dimensions by dicing or other methods.

[0122] 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 unwanted parts such as burrs generated during cutting. After barrel polishing, the dielectric green sheet laminate is washed with a cleaning solution such as water and then dried.

[0123] Next, the dielectric green sheet laminate can be debindered (plasticized) and fired to manufacture a capacitor body.

[0124] 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 180°C to 400°C, and the temperature maintenance time 0.5 hours to 24 hours. The atmosphere during debinding may be air or a reducing atmosphere.

[0125] The firing conditions can be appropriately adjusted depending on the main component composition of the dielectric layer and the internal electrode layer. For example, firing can be carried out at a temperature of 1100°C to 1400°C, for example, 1200°C to 1350°C. Furthermore, firing can be carried out for 0.5 hours to 8 hours, for example, 1 hour to 3 hours. Also, firing can 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 ~ 1.0 × 10 -10 MPa is also acceptable.

[0126] After firing, annealing can be performed as needed. Annealing is a process to re-oxidize the dielectric layer, and 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 ~ 1.0 × 10 -5 MPa is also acceptable.

[0127] For debinding, calcination, or annealing processes, a wetter, for example, can be used to humidify nitrogen gas or a mixed gas, in which case the water temperature may be between 5°C and 75°C. Debinding, calcination, and annealing processes can be performed continuously or independently.

[0128] Selectively, the third and fourth surfaces of the manufactured capacitor body 110 can be subjected to surface treatments such as sandblasting, laser irradiation, and barrel polishing. By performing such surface treatments, the edges of the first and second internal electrode layers are 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 potentially facilitating the formation of alloy parts.

[0129] Next, an external electrode is formed on one surface of the manufactured capacitor body 110.

[0130] 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.

[0131] 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 repeated explanations will be omitted. The paste for forming a sintered metal layer may also selectively contain binders, solvents, dispersants, plasticizers, oxide powders, etc. Binders can include, for example, ethyl cellulose, acrylic, butyral, and solvents can include organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, and toluene, or aqueous solvents.

[0132] Methods for applying the sintered metal layer-forming paste to the outer surface of the capacitor body 110 include the dip method, various printing methods such as screen printing, application methods using dispensers, and spraying methods using sprays. The sintered metal layer-forming paste is applied to at least the third and fourth surfaces of the capacitor body 110, and can also be applied to parts of the first, second, fifth, or sixth surfaces where the band portions of the first and second external electrodes are selectively formed.

[0133] 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.

[0134] A conductive resin layer can be selectively formed on the outer surface of the obtained capacitor body 110 by applying a conductive resin layer-forming paste and then curing it.

[0135] The paste for forming a conductive resin layer may contain a resin and, selectively, a conductive metal or a non-conductive filler. The descriptions of conductive metals and resins are the same as those given above, so repeated explanations will be 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, or butyral, and solvents can be organic solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, or toluene, or aqueous solvents.

[0136] 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, or by printing the conductive resin layer forming paste onto the surface of the capacitor body 110 using a screen printing method or gravure printing method, or by applying the conductive resin layer forming paste to the surface of the capacitor body 110 and then curing it.

[0137] Next, a plating layer is formed on the outside of the conductive resin layer.

[0138] For example, the plating layer can be formed by a plating method, and can also be formed by sputtering or electroplating (electric deposition).

[0139] The embodiments described above will be explained in more detail below through the examples provided. However, the following examples are for illustrative purposes only and do not limit the scope of rights. [Examples]

[0140] (Manufacturing of multilayer ceramic capacitors) [Examples 1-7] A conductive paste was prepared by mixing nickel (Ni) and germanium dioxide (GeO2). In this process, GeO2 was mixed in such an amount that the Ge content was as shown in Table 1 below, relative to the total amount of Ni and Ge.

[0141] Next, a dielectric slurry was prepared using barium titanate (BaTiO3) powder. In this process, zirconia balls (ZrO2 balls) were used as the dispersion medium, and ethanol / toluene, along with a dispersant and binder, were added together and then mechanically milled.

[0142] Next, a dielectric green sheet was manufactured using a head-dispensing type on-roll molding coater with the manufactured dielectric slurry. The manufactured conductive paste was printed onto the surface of the dielectric green sheet to form a conductive paste layer.

[0143] A dielectric green sheet laminate was manufactured by laminating and pressing dielectric green sheets, each having a conductive paste layer formed on it.

[0144] The dielectric green sheet laminate was subjected to a plasticizing process at a temperature of 400°C or lower and in a nitrogen atmosphere, and then fired at a firing temperature of 1300°C or lower and a hydrogen concentration of 1.0%H2 or lower.

[0145] Next, the multilayer ceramic capacitor was manufactured through processes such as the addition of external electrodes and plating.

[0146] [Comparative Example 1] A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that a conductive paste was made using Ni alone in Example 1.

[0147] [Comparative Example 2] A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that the GeO2 was mixed in such a way that Ge accounted for 0.55 atomic percent of the total amount of Ni and Ge.

[0148] [Comparative Example 3] A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that the GeO2 was mixed with a content of Ge equal to 14.50 atomic percent relative to the total amount of Ni and Ge.

[0149] In Table 1 below, the Ge content is shown based on the total atomic weight of Ni and Ge.

[0150] [Table 1]

[0151] [Evaluation 1: XRD Analysis] X-ray diffraction (XRD) analysis was performed on the internal electrode layers of the multilayer ceramic capacitors manufactured in Examples 1-7 and Comparative Examples 1-3, and the results are shown in Figures 5 and 6 and Table 2 below.

[0152] Specifically, XRD analysis was performed on the internal electrode layer of the multilayer ceramic capacitor manufactured after firing in Example 3 and on the raw material powder used for forming the internal electrode layer before firing in Example 3, and the results are shown in Figures 5 and 6 below.

[0153] Specifically, after curing the multilayer ceramic capacitor in an epoxy mixture, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body were polished to a depth of 1 / 2 in the L-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 intersect. Next, Cu K was applied to the internal electrode layer in the active region of the cross-sectional sample. α X-ray diffraction (XRD) analysis was performed using a line, and the spatial lattice edge length of nickel (Ni) was calculated from the results as follows. Specifically, the spatial lattice edge length of nickel (Ni) was calculated by dividing the active region of the cross-sectional sample into three equal parts: upper, middle, and lower. Three points were selected within the internal electrode layer of each region, and the average value of these nine points was calculated.

[0154] Furthermore, the raw material powder was measured after being produced as pellets by mixing Ni and GeO2.

[0155] Figure 5 shows the XRD (X-ray diffraction analysis) graphs for the internal electrode layer manufactured after firing and the raw material powder for forming the internal electrode layer before firing according to Example 3, and Figure 6 is a magnified graph showing the Ni(220) portion in the XRD results for the internal electrode layer manufactured after firing and the raw material powder for forming the internal electrode layer before firing according to Example 3.

[0156] Referring to Figure 5, the XRD measurement results for the raw material powder according to Example 3 showed peaks for Ni, NiO present on the Ni surface, and GeO2. On the other hand, the XRD measurement results for the internal electrode layer manufactured after calcination according to Example 3 showed only a peak for Ni. This suggests that GeO2 was reduced to Ge during the calcination process and then dissolved into the Ni.

[0157] Furthermore, referring to Figure 5, it can be seen that the Ni peak on the XRD graph for the raw material powder is located relatively to the right compared to the Ni peak on the XRD graph for the internal electrode layer. Also, referring to Figure 6, it can be seen that the Ni peak of the internal electrode layer after firing has shifted relatively to the left compared to the case of the raw material powder. This can be seen as Ge being located within the Ni spatial lattice of the internal electrode layer, increasing the spatial lattice side length of Ni. Thus, it can be seen that the spatial lattice side length of Ni in the internal electrode layer manufactured from raw material powder composed of Ni and GeO2, as in Example 3, is increased compared to the internal electrode layer formed from Ni only as the raw material powder, as in Comparative Example 1.

[0158] On the other hand, the Bragg angle θ can be obtained using the position 2θ of the Ni peak in the internal electrode layer on the XRD graph, and the interplane distance can be calculated using this Bragg angle to determine the spatial lattice edge length of Ni. Specifically, the spatial lattice edge lengths of Ni obtained through XRD analysis of the internal electrode layers manufactured in Examples 1 to 7 and Comparative Examples 1 to 3 were calculated using the following formula 1, and the results are shown in Table 2 below.

[0159]

Number

[0160] In the above formula (1), λ is Cu K α which is 1.5406 Å, h, k, and l are plane indices, and θ is the Bragg angle.

[0161] Also, X-ray diffraction analysis (XRD) was performed on the dielectric layers of the multilayer ceramic capacitors manufactured in Examples 1 to 7 and Comparative Examples 1 to 3, and the lattice parameter of BaTiO3 obtained through the XRD analysis was calculated by the above formula (1). Next, the difference value between the obtained lattice parameter of Ni and the lattice parameter of BaTiO3 was determined, and the results are shown in Table 2 below.

[0162] From Table 2 below, it can be seen that the lattice parameter of Ni in the internal electrode layer according to Examples 1 to 7 has a range of 3.522 Å to 3.544 Å.

[0163] Specifically, in the case of Comparative Example 1, the lattice parameter of Ni was 3.520 Å, and in the case of Example 3, the lattice parameter of Ni was calculated to be 3.526 Å. That is, in the case of Example 3, it can be confirmed that the lattice parameter of Ni increased by 0.006 Å compared with Comparative Example 1, and the difference from the lattice parameter of BaTiO3 in the dielectric layer decreased by 0.006 Å.

[0164] [Evaluation 2: SEM-EDS Analysis] SEM-EDS (scanning electron microscope - energy dispersive spectroscopy) analysis was performed on the multilayer ceramic capacitors manufactured in Examples 1 to 7 and Comparative Examples 1 to 3, and the results are shown in Table 2 below and FIG. 7.

[0165] Specifically, the multilayer ceramic capacitors manufactured in Examples 1-7 and Comparative Examples 1-3 were cured in an epoxy mixture. Then, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body were polished to a depth of 1 / 2 in the L-axis direction. After fixing, the capacitors were maintained in a vacuum atmosphere chamber to obtain cross-sectional samples that allowed observation of the active region where the dielectric layer and internal electrode layer intersected. Next, the active region of the cross-sectional sample was measured using a scanning electron microscope (SEM) so that at least six layers each of the dielectric layer and internal electrode layer were visible. The SEM was performed using a Thermofisher Scientific Verios G4 product at 10kV in an approximately 6μm × 6μm area where at least six layers each of the dielectric layer and internal electrode layer were visible in the active region. Subsequently, energy-dispersive spectroscopy (EDS) analysis was performed on the internal electrode layer through the SEM image of the measured cross-sectional sample to calculate the content of Ni, Ge, etc., within the internal electrode layer. Specifically, when the active region of the cross-sectional sample was divided into three equal parts—upper, middle, and lower—three points within the internal electrode layer were selected for each region, and the average content of Ni, Ge, etc., at a total of nine points was calculated.

[0166] Energy-dispersive spectroscopy (EDS) analysis was performed on arbitrary points within the internal electrode layer.

[0167] Figure 7 shows the SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis of the internal electrode layer according to Example 3.

[0168] Referring to Figure 7, it can be confirmed that the internal electrode layer according to Example 3 contains nickel (Ni) and germanium (Ge), and that germanium (Ge) is present at 2.05 atomic percent relative to the total amount of Ni and Ge. It can also be seen that Ge is dissolved in Ni. The Ba and Ti partially detected in the internal electrode layer are elements that constitute the dielectric layer and have migrated to the internal electrode layer. Unlike Ge, the XRD results in Figure 5 show that Ba and Ti are not dissolved in the internal electrode layer.

[0169] Furthermore, Table 2 below confirms that the internal electrode layers in Examples 1 to 7 contain nickel (Ni) and germanium (Ge), with germanium (Ge) present in a range of 0.95 atomic% to 11.95 atomic% relative to the total amount of Ni and Ge. On the other hand, the internal electrode layer in Comparative Example 1 does not contain germanium (Ge), while the internal electrode layers in Comparative Examples 2 and 3 contain germanium (Ge) in amounts exceeding the specified range.

[0170] [Table 2]

[0171] [Rating 3: Moisture resistance reliability] The moisture resistance reliability of the multilayer ceramic capacitors manufactured in Examples 1-7 and Comparative Examples 1-3 was measured, and the results are shown in Table 3 below.

[0172] Specifically, 10,000 multilayer ceramic capacitors manufactured in Examples 1-7 and Comparative Examples 1-3 were prepared and mounted on a measurement substrate. The humidity resistance reliability was then measured using an ESPEC (PR-3J, 8585) apparatus under conditions of 85°C, 85% relative humidity (RH), 6.5V, and 500 hours.

[0173] The results of the moisture resistance reliability test showed that the IR (insulation resistance) was 1 × 10⁻⁶. 4 Units with a resistance of less than ohms were judged as defective, and the defect rate (%) was shown based on a total of 10,000 units.

[0174] Table 3 below shows that in Examples 1 to 7, where the spatial lattice side length of Ni in the internal electrode layer satisfies the range of 3.522 Å to 3.544 Å, the moisture resistance reliability is superior compared to Comparative Examples 1 to 3.

[0175] [Rating 4: Cracks appearing] The degree of crack initiation was measured for the multilayer ceramic capacitors manufactured in Examples 1-7 and Comparative Examples 1-3, and the results are shown in Table 3 below.

[0176] Specifically, 100 multilayer ceramic capacitors were prepared for each of Examples 1-7 and Comparative Examples 1-3. After curing them in an epoxy mixture, the W-axis and T-axis surfaces (WT surfaces) of the capacitor body were polished in the L-axis direction to a depth of 1 / 2 to obtain cross-sectional samples. Next, the active region, cover region, and side margin region of the cross-sectional sample were measured using a scanning electron microscope (SEM) to confirm crack occurrence. The SEM was performed using a Thermofisher Scientific Verios G4 product under conditions of 10kV. Based on the measurement results, products in which a crack occurred in even one place within the entire region were judged to be defective. In this case, the crack was judged to have a major axis length of 10 nm or more. The number of products judged to be defective based on a total of 100 units is shown in Table 3 below.

[0177] Table 3 below shows that in Examples 1 to 7, where the spatial lattice side length of Ni in the internal electrode layer satisfies the range of 3.522 Å to 3.544 Å, the degree of crack initiation is reduced compared to Comparative Examples 1 to 3.

[0178] [Table 3]

[0179] While preferred embodiments of the present invention have been described above, the present invention is not limited thereto. It can be implemented in various ways within the scope of the claims, the detailed description of the invention, and the attached drawings, and these also naturally fall within the scope of the present invention. [Explanation of symbols]

[0180] 100: Multilayer ceramic capacitor 110: Capacitor body 111: Dielectric layer 121: First internal electrode layer 122: Second internal electrode layer 131: 1st external electrode 132:Second external electrode

Claims

1. A capacitor body including a dielectric layer and an internal electrode layer, The capacitor body includes an external electrode disposed on the outside of the capacitor body, The internal electrode layer contains nickel (Ni), Multilayer ceramic capacitor: The spatial lattice edge length of the nickel (Ni) obtained from the following formula 1 through X-ray diffraction analysis (XRD) of the internal electrode layer is 3.522 Å or more and 3.544 Å or less. [Math 1] (In the above formula 1, λ is Cu K) α This is 1.5406 Å, where h, k, and l are plane indices, and θ is the Bragg angle.

2. The multilayer ceramic capacitor according to claim 1, wherein the dielectric layer comprises a barium titanate-based compound.

3. The difference between the spatial lattice side length of the nickel (Ni) and the spatial lattice side length of the barium titanate compound is 0.492 Å or more and 0.515 Å or less. The multilayer ceramic capacitor according to claim 2, wherein the spatial lattice side length of the barium titanate compound is obtained from formula 1 by X-ray diffraction analysis (XRD) of the dielectric layer.

4. The multilayer ceramic capacitor according to claim 1, wherein the internal electrode layer further comprises germanium (Ge).

5. The multilayer ceramic capacitor according to claim 4, wherein the germanium (Ge) is solid-dissolved inside the nickel (Ni).

6. The multilayer ceramic capacitor according to claim 4, wherein the germanium (Ge) is contained in the internal electrode layer in an amount of 0.95 atomic% to 11.95 atomic% relative to the total amount of nickel (Ni) and germanium (Ge).

7. The multilayer ceramic capacitor according to claim 1, wherein the internal electrode layer further comprises one or more selected from copper (Cu), silver (Ag), palladium (Pd), gold (Au), and alloys thereof.

8. The multilayer ceramic capacitor according to claim 1, wherein the dielectric layer contains germanium (Ge).

9. The multilayer ceramic capacitor according to claim 1, wherein the average thickness of the internal electrode layer is 0.1 μm or more and 1 μm or less.

10. The multilayer ceramic capacitor according to claim 1, wherein the average thickness of the dielectric layer is 0.1 μm or more and 8.0 μm or less.

11. The process involves mixing nickel (Ni) and germanium (Ge) based raw materials to produce a conductive paste, The process involves manufacturing a dielectric green sheet using a dielectric slurry, and printing the conductive paste onto the surface of the dielectric green sheet to form a conductive paste layer, A step of manufacturing a dielectric green sheet laminate by stacking the dielectric green sheets on which the conductive paste layer is formed, The steps include: firing the dielectric green sheet laminate to manufacture a capacitor body including a dielectric layer and an internal electrode layer; The step includes forming an external electrode on the outside of the capacitor body, The internal electrode layer contains nickel (Ni), A method for manufacturing a multilayer ceramic capacitor, wherein the spatial lattice edge length of the nickel (Ni) obtained from the following formula 1 through X-ray diffraction analysis (XRD) of the internal electrode layer is 3.522 Å or more and 3.544 Å or less: [Math 2] (In the above formula 1, λ is Cu K) α This is 1.5406 Å, where h, k, and l are plane indices, and θ is the Bragg angle.

12. The method for manufacturing a multilayer ceramic capacitor according to claim 11, wherein the germanium (Ge)-based raw material is Ge, an oxide of Ge, a nitride of Ge, a salt compound of Ge, or a compound in the form of a sol in which Ge is dispersed in an organic solvent.

13. The method for manufacturing a multilayer ceramic capacitor according to claim 11, wherein the germanium (Ge)-based raw material is contained in an amount such that Ge is 0.95 atomic% or more and 11.95 atomic% or less relative to the total amount of nickel (Ni) and the germanium (Ge)-based raw material.

14. The steps of manufacturing a conductive paste containing nickel (Ni), A step of producing a dielectric slurry containing a barium titanate-based compound containing barium (Ba), titanium (Ti), and germanium (Ge), The steps include: manufacturing a dielectric green sheet using the dielectric slurry, and printing the conductive paste onto the surface of the dielectric green sheet to form a conductive paste layer; A step of manufacturing a dielectric green sheet laminate by stacking the dielectric green sheets on which the conductive paste layer is formed, The steps include: firing the dielectric green sheet laminate to manufacture a capacitor body including a dielectric layer and an internal electrode layer; The step includes forming an external electrode on the outside of the capacitor body, The internal electrode layer contains nickel (Ni), A method for manufacturing a multilayer ceramic capacitor, wherein the spatial lattice edge length of the nickel (Ni) obtained from the following formula 1 through X-ray diffraction analysis (XRD) of the internal electrode layer is 3.522 Å or more and 3.544 Å or less: [Math 3] (In the above formula 1, λ is Cu K) α This is 1.5406 Å, where h, k, and l are plane indices, and θ is the Bragg angle.

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