Multilayer ceramic capacitor

Abstract

The present disclosure provides a multilayer ceramic capacitor including: a ceramic body configured to include a plurality of dielectric layers and a plurality of internal electrodes arranged such that the dielectric layers are disposed between the plurality of internal electrodes; and external electrodes disposed at opposite sides of the ceramic body in the first direction. The external electrode includes: a first glass portion positioned on a first direction end surface of the ceramic body and connected to the internal electrode; and a second glass portion positioned on a portion of at least one of a second direction side surface and a third direction side surface of the ceramic body, and including an iron (Fe) component.

Description

Technical Field

[0001] This disclosure relates to a multilayer ceramic capacitor. Background Technology

[0002] Ceramic electronic components using ceramic materials include capacitors, inductors, piezoelectric elements, varistors, or thermistors. Among such ceramic electronic components, multilayer ceramic capacitors (MLCCs) are used in a variety of electronic devices due to their small size, high capacitance, and ease of installation.

[0003] Multilayer ceramic capacitors can be surface-mount electronic components installed in circuit boards of various electronic products, such as imaging devices (such as liquid crystal displays (LCDs), plasma display panels (PDPs) and organic light-emitting diode (OLED) displays), computers, and personal portable terminals (e.g., smartphones) for charging or discharging.

[0004] As the operating environments of multilayer ceramic capacitors become more diverse, their moisture resistance reliability is considered important.

[0005] Multilayer ceramic capacitors may include an inner electrode disposed inside a ceramic body and an outer electrode disposed outside the ceramic body and connected to the inner electrode. To miniaturize multilayer ceramic capacitors and increase their effective capacitance, methods are needed to increase the size of the ceramic body and make the outer electrode as thin as possible.

[0006] However, as the thickness of the external electrode is reduced to increase the size of the ceramic body, the hermetic seal of the external electrode deteriorates, which may lead to a deterioration in the moisture resistance reliability of multilayer ceramic capacitors. Summary of the Invention

[0007] One aspect of this disclosure provides a multilayer ceramic capacitor that can ensure a hermetically sealed design while reducing the thickness of the external electrodes.

[0008] However, the problems to be solved by this disclosure are not limited to those described above, and various extensions are possible within the scope of the technical spirit included in this disclosure.

[0009] This disclosure provides a multilayer ceramic capacitor, comprising: a ceramic body including a plurality of dielectric layers and a plurality of internal electrodes arranged such that the dielectric layers are disposed between the plurality of internal electrodes; and an external electrode disposed on opposite sides of the ceramic body in a first direction. The external electrode comprises: a first glass portion positioned on the first-direction end surface of the ceramic body and connected to the internal electrodes; and a second glass portion positioned on a portion of at least one of a second-direction side surface and a third-direction side surface of the ceramic body, and comprising an iron (Fe) composition.

[0010] The second glass portion may contain 5 wt% to 10 wt% iron (Fe) content.

[0011] For the external electrode, T2 / T1 can be greater than or equal to 0.4 and less than or equal to 1, where T1 is the thickness of the external electrode in the first direction at the central portion of the first direction end surface of the ceramic body, and T2 is the thickness of the external electrode at the edge between the first direction end surface of the ceramic body and at least one of the second direction side surface and the third direction side surface.

[0012] Here, T2 / T1 can be greater than or equal to 0.4 and less than or equal to 0.6.

[0013] The first glass portion may include a metal containing copper (Cu) or nickel (Ni), and may also include Ba-based glass or Zn-based glass.

[0014] The second glass portion may include a metal containing copper (Cu) or nickel (Ni), and may also include Ba-based glass or Zn-based glass.

[0015] The second glass portion may include Fe-based glass, wherein the Fe in the second glass portion is Fe from the Fe-based glass.

[0016] The multilayer ceramic capacitor may further include a plating layer covering the first glass portion and the second glass portion.

[0017] This disclosure provides a multilayer ceramic capacitor, comprising: a ceramic body including a plurality of dielectric layers and a plurality of internal electrodes arranged such that the dielectric layers are disposed between the plurality of internal electrodes; and an external electrode disposed on an opposite side of the ceramic body in a first direction. The external electrode comprises a metallic component and a glass component, and the glass component in a portion of the external electrode positioned on at least one of a second-direction side surface and a third-direction side surface of the ceramic body comprises an iron (Fe) component.

[0018] The external electrode may contain 5 wt% to 10 wt% iron (Fe).

[0019] For the external electrode, T2 / T1 can be greater than or equal to 0.4 and less than or equal to 1, where T1 is the thickness of the external electrode in the first direction at the central portion of the first direction end surface of the ceramic body, and T2 is the thickness of the external electrode at the edge between the first direction end surface of the ceramic body and at least one of the second direction side surface and the third direction side surface.

[0020] Here, T2 / T1 can be greater than or equal to 0.4 and less than or equal to 0.6.

[0021] The metallic component may include copper (Cu) or nickel (Ni).

[0022] The glass composition may include Ba-based glass or Zn-based glass.

[0023] This disclosure provides a multilayer ceramic capacitor, comprising: a ceramic body including a plurality of dielectric layers, a plurality of first internal electrodes, and a plurality of second internal electrodes, wherein the first internal electrodes and the second internal electrodes are arranged such that the dielectric layers are disposed between the first internal electrodes and the second internal electrodes; and a first external electrode and a second external electrode, respectively disposed on opposite sides of the ceramic body in a first direction. The first external electrode includes: a first glass portion positioned on the first-direction end surface of the ceramic body, connected to the first internal electrode, and having Fe; and a second glass portion positioned on a portion of at least one of a second-direction side surface and a third-direction side surface of the ceramic body, having iron (Fe), wherein the iron (Fe) content in the second glass portion is greater than the iron (Fe) content in the first glass portion.

[0024] At the edge between the first directional end surface and at least one of the second directional side surface and the third directional side surface of the ceramic body, the iron (Fe) content in the first external electrode may decrease along the path from the second glass portion to the first glass portion.

[0025] According to the embodiment of the multilayer ceramic capacitor, the effective capacitance of the multilayer ceramic capacitor can be increased by reducing the thickness of the outer electrode, and the moisture resistance reliability of the multilayer ceramic capacitor can be improved by ensuring the hermetic sealing of the outer electrode.

[0026] However, it is readily understood that the effects of this disclosure are not limited to those described above, and various extensions may be made without departing from the spirit and scope of this disclosure. Attached Figure Description

[0027] Figure 1 This is a schematic perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0028] Figure 2 It shows along Figure 1 The cross-sectional view taken from line II-II'.

[0029] Figure 3 It shows Figure 2 A magnified view of region A.

[0030] Figure 4 It is shown Figure 1A three-dimensional diagram of the stacked structure in a multilayer ceramic capacitor.

[0031] Figure 5 This is a digital image showing a portion of a multilayer ceramic capacitor according to an embodiment.

[0032] Figure 6 This is a digital image showing a portion of a multilayer ceramic capacitor according to an embodiment.

[0033] Figure 7 This is a digital image showing a portion of a multilayer ceramic capacitor according to Comparative Example 1.

[0034] Figure 8 This is a digital image showing a portion of a multilayer ceramic capacitor according to Comparative Example 2. Detailed Implementation

[0035] In the following, various embodiments of this disclosure will be described in detail to enable those skilled in the art to readily implement this disclosure with reference to the accompanying drawings. The drawings and description are to be considered illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals denote the same elements. Furthermore, some components in the drawings are exaggerated, omitted, or shown schematically, and the dimensions of each component do not perfectly reflect the actual dimensions.

[0036] The accompanying drawings are provided only to facilitate an understanding of the embodiments disclosed in this specification and should not be construed as limiting the spirit of the disclosure herein. It should be understood that the invention includes all modifications, equivalents, and alternatives that do not depart from the scope and spirit of the invention.

[0037] Terms including ordinal numbers such as first, second, etc., will be used only to describe various components and should not be interpreted as limiting these components. These terms are only used to distinguish one component from other components.

[0038] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, that element may be directly on the other element, or there may be an intermediate element present. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element present. Furthermore, in the specification, the terms "on" or "above" mean positioned on or below the object portion, and do not necessarily mean positioned on the upper side of the object portion based on a direction opposite to the direction of gravity.

[0039] It will be further understood that the terms “comprising / including” or “having” as used throughout the specification enumerate the presence of the stated features, quantities, steps, operations, components, parts, or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, steps, operations, components, parts, or combinations thereof. Therefore, unless expressly stated to the contrary, the words “comprising” and variations such as “including” or “having” will be understood to imply the inclusion of the stated components without excluding any other components.

[0040] Furthermore, throughout the instruction manual, the phrase "in a plan view" refers to the view of the object from above, and the phrase "in a cross-sectional view" refers to the view of the cross-section taken by vertically cutting the object from the side.

[0041] Furthermore, throughout the specification, "connection" can mean not only a direct connection between two or more components, but also an indirect connection between two or more components through other components. It can mean not only a physical connection, but also an electrical connection, and it can also mean a situation where the components are referred to by different names due to their location and / or function, but are actually a single unit.

[0042] Figure 1 This is a schematic perspective view showing a multilayer ceramic capacitor according to an embodiment. Figure 2 It shows along Figure 1 A cross-sectional view taken from line II-II'. Figure 3 It shows Figure 2 A magnified view of region A. Figure 4 It is shown Figure 1 A three-dimensional diagram of the stacked structure in a multilayer ceramic capacitor. Figure 5 This is a digital image showing a portion of a multilayer ceramic capacitor according to an embodiment, and Figure 6 This is a digital image showing a portion of a multilayer ceramic capacitor according to an embodiment.

[0043] Reference Figures 1 to 6 According to this embodiment, the multilayer ceramic capacitor 100 may include a ceramic body 110, a first external electrode 120, a second external electrode 130, a plurality of first internal electrodes 150 and a plurality of second internal electrodes 160.

[0044] First, when defining directions to clearly describe this embodiment, the L-axis, W-axis, and T-axis indicated in the drawings respectively indicate the axes representing the length direction, width direction, and thickness direction of the multilayer ceramic capacitor 100.

[0045] The thickness direction (T-axis direction) can be a direction perpendicular to the wide surface (main surface) of a component with a sheet-like shape. For example, the thickness direction (T-axis direction) can be used as the same concept as the direction of the stacked dielectric layer 140.

[0046] The length direction (L-axis direction) can be a direction parallel to the wide surface (main surface) of the sheet assembly and intersecting (or orthogonal) to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) can be the direction in which the first external electrode 120 and the second external electrode 130 are opposite to each other.

[0047] The width direction (W-axis direction) can be a direction that is parallel to the wide surface (main surface) of the sheet component and intersects (or is orthogonal) to both the thickness direction (T-axis direction) and the length direction (L-axis direction).

[0048] The ceramic body 110 may be formed into a generally hexahedral shape, but this embodiment is not limited to this. Due to shrinkage during sintering, the ceramic body 110 may have a generally hexahedral shape, rather than a perfect hexahedral shape. For example, the ceramic body 110 may have a generally regular hexahedral shape, for example, the portions corresponding to the corners or vertices may each have a rounded shape.

[0049] In this embodiment, for better understanding and ease of description, surfaces that are opposite to each other in the length direction (L-axis direction) are defined as length direction end surfaces or first surface S1 and second surface S2. Surfaces that are opposite to each other in the width direction (W-axis direction) and connect the first surface S1 and the second surface S2 are defined as width direction side surfaces opposite to the third surface S3 and the fourth surface S4. Surfaces that are opposite to each other in the thickness direction (T-axis direction) and connect the first surface S1, the second surface S2, the third surface S3 and the fourth surface S4 are defined as thickness direction side surfaces or fifth surface S5 and the sixth surface S6.

[0050] Therefore, the first direction in which the first surface S1 and the second surface S2 are opposite to each other can be the length direction (L-axis direction), and the second and third directions perpendicular to the first direction and perpendicular to each other can be the thickness direction (T-axis direction) and the width direction (W-axis direction) or the width direction (W-axis direction) and the thickness direction (T-axis direction).

[0051] Furthermore, the area between the longitudinal end surface and the thickness or width side surface of the ceramic body 110 is defined as an edge portion. That is, the curved portion (i.e., the corner portion) between the third surface S3 to the sixth surface S6 and the first surface S1 can be referred to as the first edge portion C1, and the curved portion (i.e., the corner portion) between the third surface S3 to the sixth surface S6 and the second surface S2 can be referred to as the second edge portion C2.

[0052] The length of the ceramic body 110 can refer to the maximum length of a plurality of line segments connecting the two outermost boundary lines opposite each other in the length direction (L-axis direction) and parallel to the length direction (L-axis direction) of the ceramic body 110 as shown in the cross-sectional photograph, taken from an optical microscope photograph or a scanning electron microscope (SEM) photograph of the cross-section of the ceramic body 110 located at its center in the width direction (W-axis direction) and at its center in the length direction (L-axis direction). Alternatively, the length of the ceramic body 110 can refer to the minimum length of a plurality of line segments connecting the two outermost boundary lines opposite each other in the length direction (L-axis direction) of the ceramic body 110 as shown in the cross-sectional photograph. Alternatively, the length of the ceramic body 110 can refer to the arithmetic mean of the lengths of at least two line segments connecting the two outermost boundary lines opposite each other in the length direction (L-axis direction) of the ceramic body 110 as shown in the cross-sectional photograph.

[0053] The thickness of the ceramic body 110 can refer to the maximum length of a plurality of line segments connecting the two outermost boundary lines opposite each other in the thickness direction (T-axis direction) of the ceramic body 110 shown in the cross-sectional photograph, taken from an optical microscope or scanning electron microscope (SEM) image of the cross-section of the ceramic body 110 located at its center in the width direction (W-axis direction) and parallel to the thickness direction (T-axis direction). Alternatively, the thickness of the ceramic body 110 can refer to the minimum length of a plurality of line segments connecting the two outermost boundary lines opposite each other in the thickness direction (T-axis direction) of the ceramic body 110 shown in the cross-sectional photograph. Optionally, the thickness of the ceramic body 110 may refer to the arithmetic mean of the lengths of at least two line segments among the two outermost boundary lines of the ceramic body 110 shown in the above cross-sectional photograph that are opposite each other in the thickness direction (T-axis direction) and parallel to the thickness direction (T-axis direction).

[0054] The width of the ceramic body 110 can refer to the maximum length of a plurality of line segments connecting the two outermost boundary lines opposite each other in the width direction (W-axis direction) of the ceramic body 110 shown in the cross-sectional photograph, taken from an optical microscope or scanning electron microscope (SEM) image of the cross-section of the ceramic body 110 in the length direction (L-axis direction) and parallel to the width direction (W-axis direction). Alternatively, the width of the ceramic body 110 can refer to the minimum length of a plurality of line segments connecting the two outermost boundary lines opposite each other in the width direction (W-axis direction) of the ceramic body 110 shown in the cross-sectional photograph. Optionally, the width of the ceramic body 110 may refer to the arithmetic mean of the lengths of at least two line segments among the two outermost boundary lines that are opposite each other in the width direction (W-axis direction) and parallel to the width direction (W-axis direction) of the ceramic body 110 shown in the above cross-sectional photograph.

[0055] The ceramic body 110 may include a plurality of dielectric layers 140 stacked in the thickness direction (T-axis direction). The boundaries between adjacent dielectric layers 140 may be unclear. For example, it is difficult to see the boundaries between adjacent dielectric layers 140 without the use of a scanning electron microscope (SEM), and the plurality of dielectric layers 140 may appear as a single structure (e.g., integrated with each other).

[0056] The first inner electrode 150 and the second inner electrode 160 may be stacked alternately, and a dielectric layer 140 is disposed between them. This stacking structure may be repeated within the ceramic body 110. The inner electrode closest to the fifth surface S5 of the ceramic body 110 may be either the first inner electrode 150 or the second inner electrode 160, and the inner electrode closest to the sixth surface S6 may be either the first inner electrode 150 or the second inner electrode 160.

[0057] The first inner electrode 150 and the second inner electrode 160 may have different polarities and may be electrically insulated from each other by a dielectric layer 140 disposed between them.

[0058] The first inner electrode 150 and the second inner electrode 160 may be arranged to be offset from each other in the longitudinal direction (L-axis direction), and a dielectric layer 140 is disposed between the first inner electrode 150 and the second inner electrode 160. One end of the first inner electrode 150 may be exposed through the first surface S1 of the ceramic body 110, and one end of the second inner electrode 160 may be exposed through the second surface S2 of the ceramic body 110. The end of the first inner electrode 150 exposed from the first surface S1 of the ceramic body 110 may be connected to the first outer electrode 120. The end of the second inner electrode 160 exposed from the second surface S2 of the ceramic body 110 may be connected to the second outer electrode 130.

[0059] The first inner electrode 150 and the second inner electrode 160 can be formed by printing a conductive paste comprising a conductive metal onto the surface of the dielectric layer 140. For example, a conductive paste comprising nickel (Ni) or a nickel (Ni) alloy can be printed onto the surface of the dielectric material layer by screen printing or gravure printing to form the inner electrodes. However, this embodiment is not limited to this.

[0060] In addition, the average thickness of the first inner electrode 150 and the second inner electrode 160 can be approximately greater than or equal to 0.1 μm and less than or equal to 2 μm.

[0061] Here, the thickness of the inner electrode can represent the average thickness of an inner electrode positioned between two dielectric layers. The average thickness of the inner electrode can be the arithmetic mean of the thickness of one inner electrode shown in the aforementioned cross-sectional photograph taken at 10,000 magnification for a cross-section of the central portion of the ceramic body 110 in the width direction (W-axis direction) and in the length direction (L-axis direction) and thickness direction (T-axis direction), measured at 30 points evenly spaced along the length direction (L-axis direction). The 30 points mentioned above can be specified in the effective area described below. Thus, the average thickness of the inner electrode can be more generalized by measuring the average thickness of each of 10 inner electrodes and then taking the arithmetic mean of the measurements.

[0062] When a voltage is applied to the first external electrode 120 and the second external electrode 130, charge accumulates between the first internal electrode 150 and the second internal electrode 160, which are opposite each other. That is, capacitance can be obtained between the first internal electrode 150, which is electrically connected to the first external electrode 120, and the second internal electrode 160, which is electrically connected to the second external electrode 130. The capacitance of the multilayer ceramic capacitor 100 is proportional to the stacked area of ​​the first internal electrode 150 and the second internal electrode 160, which are stacked together along the thickness direction (T-axis direction).

[0063] In other words, the multilayer ceramic capacitor 100 may include an effective region and an edge region. The effective region may refer to the area where the first inner electrode 150 and the second inner electrode 160 are stacked along the thickness direction (T-axis direction), and the edge region may refer to the area between the effective region and the third surface S3 of the ceramic body 110 and the area between the effective region and the fourth surface S4 of the ceramic body 110.

[0064] Multilayer ceramic capacitors 100 can be classified based on their length and width. Therefore, even in multilayer ceramic capacitors with the same length and / or width, the size of the ceramic body can vary depending on the thickness of the outer electrode. That is, a multilayer ceramic capacitor with a thinner outer electrode can have a larger ceramic body compared to one with a thicker outer electrode. A larger ceramic body can represent a larger effective area as described above, which in turn can represent a larger electrostatic capacitance. Ultimately, as the outer electrode of the multilayer ceramic capacitor becomes thinner, the capacitance can increase. In this embodiment, by forming a thin electrode layer on the first and second surfaces of the ceramic body, the thickness of the outer electrode can be reduced, and thus beneficial effects can be obtained. This will be described in more detail below.

[0065] A first cover layer 143 and a second cover layer 145 may be arranged on the outer side of the effective area in the thickness direction (T-axis direction).

[0066] The first cover layer 143 may be disposed between the fifth surface S5 of the ceramic body 110 and the inner electrode closest to the fifth surface S5. The second cover layer 145 may be disposed between the sixth surface S6 of the ceramic body 110 and the inner electrode closest to the sixth surface S6.

[0067] That is, a first capping layer 143 with a predetermined thickness may be disposed above the inner electrode located at the uppermost part of the ceramic body 110, and a second capping layer 145 may be disposed below the inner electrode located at the lowermost part of the ceramic body 110. The first capping layer 143 and the second capping layer 145 may have the same composition as the dielectric layer 140. The first capping layer 143 and the second capping layer 145 may be formed by stacking one or more dielectric layers on the outer surface (i.e., the upper surface) of the uppermost inner electrode and the outer surface (i.e., the lower surface) of the lowermost inner electrode, respectively.

[0068] The first cover layer 143 and the second cover layer 145 can be used to prevent damage to the first inner electrode 150 and the second inner electrode 160 due to physical stress and / or chemical stress.

[0069] The dielectric layer 140 may comprise a ceramic material having a high dielectric constant. For example, the ceramic material may comprise a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. Furthermore, auxiliary components such as manganese (Mn) compounds, iron (Fe) compounds, chromium (Cr) compounds, cobalt (Co) compounds, and nickel (Ni) compounds may also be included in these components. Examples of ceramic materials for the dielectric layer may include (BaTiO3) in which calcium (Ca), zirconium (Zr), etc., are partially dissolved in BaTiO3. 1-x Ca x TiO3 (0) <x<1)、Ba(Ti1-y Ca y )O3 (0 < y < 1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (0 < x < 1, 0 < y < 1), Ba(Ti 1-y Zr y )O3 (0 < y < 1), etc., but the present disclosure is not limited thereto.

[0070] In addition, the dielectric layer 140 may further include at least one of a ceramic additive, an organic solvent, a plasticizer, a binder, and a dispersant. As the ceramic additive, a transition metal oxide or a transition metal carbide, a rare earth element, magnesium (Mg), or aluminum (Al) may be used.

[0071] For example, the average thickness of the dielectric layer 140 may be from 0.1 μm to 10 μm, but the present embodiment is not limited thereto.

[0072] The first external electrode 120 and the second external electrode 130 are positioned outside the ceramic body 110. The first external electrode 120 and the second external electrode 130 may be positioned at opposite sides of the ceramic body 110 in the first direction.

[0073] The first external electrode 120 may be positioned on the first surface S1 of the ceramic body 110 and may extend to at least one of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6. The second external electrode 130 may be positioned on the second surface S2 of the ceramic body 110 and may extend to at least one of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6.

[0074] The first external electrode 120 may include a metal and a glass. Here, the metal may include a conductive metal such as copper (Cu) or nickel (Ni), and the glass may include an oxide-based glass.

[0075] The first external electrode 120 may include a first glass portion 121 and a second glass portion 123. <00….

[0076] The first glass portion 121 may be positioned on the first surface S1 of the ceramic body 110 and may be electrically connected to the exposed end of the first internal electrode 150.

[0077] The first glass portion 121 may include a metal and a glass. Here, the metal may include a conductive metal such as copper (Cu) or nickel (Ni), and the glass may include a Ba-based glass or a Zn-based glass.

[0078] The first glass portion 121 can be formed by a semi-dry impregnation method. Specifically, the first glass portion 121 can be formed by semi-drying a paste containing conductive metal and glass, applying it to the first surface S1 of the ceramic body 110 and drying it, and then performing a heat treatment known as electrode firing.

[0079] Reference Figure 5 It can be seen that the center of the first glass portion 121 is generally flat, and referring to... Figure 6 As can be seen, according to this embodiment, the thickness of the first external electrode 120 is ensured to be at a specific level or greater in the corner region (i.e., the first edge portion C1) between the fifth surface S5 and the first surface S1 of the ceramic body 110.

[0080] Unlike this embodiment, when a high-viscosity paste is applied to the first surface S1 of the ceramic body 110 using a conventional impregnation method, dried, and then heat-treated, the high viscosity of the paste may cause capillary bridges to form. These capillary bridges may not be flat, so even after the electrode is sintered, the center of the outer electrode is convex and the corners may be thin. This may increase the thickness of the outer electrode and may lead to problems in ensuring an airtight seal.

[0081] On the other hand, according to this embodiment, by semi-drying a paste comprising metal and glass, and then coating, drying and heat-treating to form the first glass portion, the thickness of the outer electrode can be minimized, thereby increasing the effective capacitance and ensuring the hermetic seal of the outer electrode.

[0082] Additionally, the first glass portion 121, which serves as the part for electrical connection with the internal electrode, can be positioned on the first surface S1 of the ceramic body 110, and can be positioned to cover the exposed end of the first internal electrode 150 on the first surface S1 of the ceramic body 110.

[0083] The second glass portion 123 may be positioned on a portion of at least one of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110, and may include metal and glass. Here, the metal may include a conductive metal such as copper (Cu) or nickel (Ni), and the glass may include Ba-based glass, Zn-based glass, Fe-based glass, etc.

[0084] In addition to Ba-based and Zn-based glass, the second glass portion 123 may also include Fe-based glass as a glass component. Therefore, by imparting corrosion resistance by the plating solution, the airtight seal can be enhanced, thereby improving plating damage and increasing moisture resistance reliability.

[0085] Based on the overall composition of the second glass portion 123, the second glass portion 123 may contain 5 wt% to 10 wt% iron (Fe). When the iron (Fe) content is greater than or equal to 5 wt%, the effect of corrosion-resistant glass can be achieved, and when the iron (Fe) content exceeds 10 wt%, excessive sintering of the glass may lead to reduced wettability with the metal, which may cause glass dissolution, resulting in plating failure and reduced moisture resistance reliability. In addition, at the edge between the first direction end surface and at least one of the second direction side surface and the third direction side surface of the ceramic body 110, the Fe content in the first external electrode 120 may decrease along the path from the second glass portion 123 to the first glass portion 121.

[0086] The second glass portion 123 can be formed by immersing the end of the ceramic body 110 on which the first glass portion 121 is formed into a paste containing metal and glass, and blotting it onto a porous material plate (PMP) to remove the paste coated on the outer surface of the first glass portion 121. Therefore, the second glass portion 123 can be positioned on a portion of at least one of the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6 of the ceramic body 110, and not on the outer surface of the first glass portion 121.

[0087] The first end of the second glass portion 123 may contact the first glass portion 121, and the second end of the second glass portion 123 may be positioned opposite the first end in the longitudinal direction (L-axis direction) of the ceramic body 110. The thickness of the second glass portion 123 may decrease from the center to the opposite ends.

[0088] The second glass portion 123 may contact the first glass portion 121 at the corner region (i.e., the first edge portion C1) between at least one of the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6 of the ceramic body 110 and the first surface S1. The first glass portion 121 and the second glass portion 123 are elements constituting the first external electrode 120, and may both be formed using metal and glass, so their boundaries may be blurred.

[0089] The first external electrode 120 may have a thickness T1 at the central portion of the first surface S1 of the ceramic body 110, and a thickness T2 at the corner region (i.e., the first edge portion C1) between the first surface S1 and at least one of the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6 of the ceramic body 110, wherein T2 / T1 may be 0.4 to 1, that is, greater than or equal to 0.4 and less than or equal to 1. Here, the thickness T1 may refer to the thickness of the center of the first glass portion 121 in the length direction, and the thickness T1 of the first glass portion 121 may be measured within a specific range based on the midpoint of the first surface S1 of the ceramic body 110, and the maximum thickness among them may be set as T1. Thickness T2 can refer to the thickness of the portion where the first glass portion 121 and the second glass portion 123 meet. A reference line can be set from the first edge portion C1 of the ceramic body 110 along a 45-degree direction (for example, a line at the first edge portion C1 at a 45-degree angle to the length direction can be set as a reference line). Thickness T2 can be measured from this reference line within a specific range, and the minimum thickness among them can be set as T2.

[0090] If the thickness ratio (T2 / T1) of the first external electrode 120 is less than 0.4, low moisture resistance reliability may occur, therefore it may be necessary for the thickness ratio (T2 / T1) of the first external electrode 120 to be greater than or equal to 0.4. Furthermore, when the external electrode is formed using an impregnation method with a paste containing metal and glass, the thickness ratio (T2 / T1) of the first external electrode 120 will not exceed 1 because the central portion of the external electrode is formed to be thicker than the outer portion.

[0091] The second external electrode 130 may include a third glass portion 131 and a fourth glass portion 133.

[0092] The third glass portion 131 can be positioned on the second surface S2 of the ceramic body 110 and can be electrically connected to the exposed end of the second inner electrode 160.

[0093] The fourth glass portion 133 may be positioned on a portion of at least one of the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the ceramic body 110, and may include metal and glass. The fourth glass portion 133 may include Fe-based glass as a glass composition.

[0094] Apart from the location of the second external electrode 130, the structure, material and function of the second external electrode 130 can correspond to the structure, material and function of the first external electrode 120, so a repeated description of it will be omitted.

[0095] In addition, the multilayer ceramic capacitor 100 may also include a first plating layer 180 and a second plating layer 190.

[0096] A first plating layer 180 may cover the first external electrode 120. The first plating layer 180 may include a first layer 181 and a second layer 183. The first layer 181 may be positioned on the first external electrode 120, and the second layer 183 may be positioned on the first layer 181. The first layer 181 may include nickel (Ni) and the second layer 183 may include tin (Sn), but this embodiment is not limited thereto.

[0097] The second plating layer 190 may cover the second external electrode 130. The second plating layer 190 may include a first layer 191 and a second layer 193. The first layer 191 may be positioned on the second external electrode 130, and the second layer 193 may be positioned on the first layer 191. The first layer 191 may include nickel (Ni) and the second layer 193 may include tin (Sn), but this embodiment is not limited thereto.

[0098] Experimental Example 1 In the following text, reference will be made to Figure 7 and Figure 8 Table 1 describes examples and compares the plating failure and moisture resistance reliability of Examples 1 and 2.

[0099] Figure 7 This is a digital image showing a portion of the multilayer ceramic capacitor according to Comparative Example 1, and Figure 8 This is a digital image showing a portion of the multilayer ceramic capacitor according to Comparative Example 2, and Table 1 is a table showing the capacitor contact, plating damage, and moisture resistance reliability of the example and Comparative Examples 1 and 2. In Table 1, "OK" indicates good and "X" indicates poor.

[0100] (Table 1)

[0101] In Table 1, examples involve an external electrode positioned on the outside of the ceramic body having Figures 1 to 4 The multilayer ceramic capacitor with the structure shown is an example.

[0102] Comparative Example 1 involves a multilayer ceramic capacitor in which all external electrodes are formed using conventional conductive paste, and Comparative Example 2 involves a multilayer ceramic capacitor in which all external electrodes are formed using a corrosion-resistant paste that also contains iron (Fe).

[0103] Referring to Table 1, in Comparative Example 1, the capacitor contact is good and the end surface plating failure rate is 0%, but the three-way point plating failure rate is 30%, and the moisture resistance reliability defect rate is high at 13333 ppm. Here, capacitor contact can refer to the electrical connection between the inner and outer electrodes, end surface can refer to the first or second surface of the ceramic body, and three-way point can refer to the point where the first or second surface of the ceramic body intersects with two adjacent surfaces among the third to sixth surfaces of the ceramic body. (Refer to...) Figure 7 As can be seen, in the case of Comparative Example 1, plating damage occurs at the triangular junction. Here, plating damage can be measured by removing Sn with a Sn stripping solution etchant on the external electrode on which a Ni-Sn plating has been formed, and then observing whether there is any Ni plating damage using a scanning electron microscope (SEM).

[0104] In Comparative Example 2, the plating failure rate at the three-point junction was 0%, but there was poor capacitor contact, a 60% failure rate for the terminal surface plating, and a high moisture resistance reliability defect rate of 18333 ppm. (Refer to...) Figure 8 As can be seen, in Comparative Example 2, plating damage occurred at the end surface. Therefore, it can be seen that applying anti-corrosion paste to the end surface leads to poor capacitor contact and a significant reduction in moisture resistance reliability.

[0105] On the other hand, in the example where a glass portion comprising metal and glass is positioned on the longitudinal end surface of the ceramic body as an external electrode, and a glass portion comprising iron (Fe) is positioned on the thickness and / or width side surfaces of the ceramic body, the capacitor contact is good, the end surface plating failure rate is 0%, the three-point plating failure rate is 0%, and the moisture resistance reliability defect rate is 0 ppm. Therefore, it can be confirmed that, compared to comparative examples 1 and 2, the capacitor contact and moisture resistance reliability are significantly improved.

[0106] Experimental Example 2 The following will describe the moisture resistance reliability and other defects of the iron (Fe) content of the glass portions (hereinafter referred to as "second glass portions" and "fourth glass portions") located on the thickness-direction side surface and / or width-direction side surface of the ceramic body in the external electrode for each sample.

[0107] Table 2 shows the characteristics (e.g., moisture resistance reliability) of samples with different iron (Fe) contents in the second and fourth glass sections of the external electrode. In Table 2, "NG" indicates poor.

[0108] (Table 2)

[0109] In Table 2, samples 1, 2, 6 and 7 relate to multilayer ceramic capacitors according to the comparative example, and samples 3 to 5 relate to multilayer ceramic capacitors according to the example.

[0110] Referring to Table 2, as a comparative example, in samples 1 and 2 where the iron (Fe) content in the second and fourth glass sections is less than 5 wt%, the plating solution penetration frequencies are 55% and 2%, respectively, and the wet resistance reliability defect rates are 18333 ppm and 13333 ppm, respectively, indicating that they are defective. Furthermore, both samples are found to be defective due to broken edges at the triangular points of the Ni plating. Therefore, it can be confirmed that when the iron (Fe) content is less than 5 wt%, no corrosion resistance effect is observed.

[0111] As a comparative example, in samples 6 and 7, where the iron (Fe) content in the second and fourth glass sections exceeded 10 wt%, the plating solution penetration frequency was 0% in both cases, but the moisture resistance reliability was poor, with moisture resistance reliability defect rates of 1666 ppm and 2500 ppm, respectively. Furthermore, both samples were found to be defective due to plating interruptions caused by glass dissolution. Therefore, it can be confirmed that when the iron (Fe) content exceeds 10 wt%, glass dissolution occurs due to reduced wettability with the metal caused by excessive sintering of the glass, leading to plating damage and reduced moisture resistance reliability.

[0112] On the other hand, in samples 2, 3, and 4, which are examples of samples where the iron (Fe) content in the second and fourth glass parts is 5 wt% to 10 wt%, the plating solution penetration frequency is 0% for all samples, the moisture resistance reliability defect rate is 0 ppm for all samples, and no other defects are observed. Therefore, it can be seen that the iron (Fe) content in the second and fourth glass parts of the external electrode is preferably 5 wt% to 10 wt%.

[0113] Experimental Example 3 In the following text, the moisture resistance reliability of each sample based on the ratio of the central thickness T1 to the edge thickness T2 of the outer electrode will be described with reference to Table 3.

[0114] Table 3 shows the moisture resistance reliability of various samples of 0603 type multilayer ceramic capacitors based on the thickness ratio of the central and edge portions of the outer electrode. In Table 3, "OK" indicates good and "NG" indicates poor.

[0115] (Table 3)

[0116] In Table 3, Sample 1 is the sample in which the external electrode is formed by the conventional impregnation method, Sample 2 is the sample in which the external electrode sheet transfer (EEST) method is applied to transfer dry sheet onto the ceramic body, and Samples 3 to 7 are the samples in which the semi-dry impregnation method is applied but the ratio of the thickness T2 of the edge portion of the external electrode to the thickness T1 of the central portion of the external electrode is different.

[0117] Referring to Table 3, in the case of sample 1 prepared by the conventional impregnation method and sample 2 prepared by the EEST method, the thickness ratio (T2 / T1) of the center and edge of the outer electrode is 0.05 and 0.1, respectively, indicating that the edge is relatively thin. As a result, the moisture resistance reliability defect rate is also very high, at 15833 ppm and 7500 ppm, respectively, and is therefore identified as defective.

[0118] For samples 3 and 4 prepared by the semi-dry impregnation method, the central thickness T1 of the outer electrode is the same, which is 10 μm, and the edge thickness T2 of the outer electrode is 3.6 μm and 4.2 μm, respectively, and the thickness ratio (T2 / T1) of the outer electrode is 0.36 and 0.42, respectively. Here, for sample 4, in which the thickness ratio (T2 / T1) of the outer electrode is greater than or equal to 0.4, the moisture resistance reliability defect rate is 0 and it is determined to be good, but for sample 3, in which the thickness ratio (T2 / T1) of the outer electrode is less than 0.4, the moisture resistance reliability defect rate is 833 ppm and it is determined to be poor.

[0119] For samples 5 and 6 prepared by the semi-dry impregnation method, the central thickness T1 of the outer electrode is the same, which is 9 μm, and the edge thickness T2 of the outer electrode is 3 μm and 4.1 μm, respectively, and the thickness ratio (T2 / T1) of the outer electrode is 0.33 and 0.46, respectively. Here, for sample 6, in which the thickness ratio (T2 / T1) of the outer electrode is greater than or equal to 0.4, the moisture resistance reliability defect rate is 0 and it is determined to be good, but for sample 5, in which the thickness ratio (T2 / T1) of the outer electrode is less than 0.4, the moisture resistance reliability defect rate is 833 ppm and it is determined to be poor.

[0120] In the case of sample 7 prepared by the semi-dry impregnation method, the central thickness T1 of the outer electrode is 8 μm, the edge thickness T2 of the outer electrode is 4.2 μm, and the thickness ratio (T2 / T1) of the outer electrode is 0.53, which is the highest among the samples in this test example. For sample 7, the thickness ratio (T2 / T1) of the outer electrode is greater than or equal to 0.4, the moisture resistance reliability defect rate is 0, and it is determined to be good.

[0121] Thus, it can be seen that, compared with the traditional method, the thickness ratio (T2 / T1) of the external electrode is higher in the semi-dry impregnation method, and it can also be seen that the thickness ratio (T2 / T1) of the external electrode must be greater than or equal to 0.4 to avoid poor moisture resistance reliability. In this test example, the thickness ratio (T2 / T1) of the external electrode of samples 4, 6 and 7, which were determined to be good, is greater than or equal to 0.4 and less than or equal to 0.6.

[0122] Experimental Example 4 In the following text, the moisture resistance reliability of each sample based on the ratio of the central thickness T1 to the edge thickness T2 of the outer electrode will be described with reference to Table 4.

[0123] Table 4 shows the moisture resistance reliability of various samples of the Type 1005 multilayer ceramic capacitor based on the thickness ratio of the central and edge portions of the outer electrode. In Table 4, "OK" indicates good and "NG" indicates poor.

[0124] (Table 4)

[0125] In Table 4, Sample 1 is the sample in which the external electrode is formed by the conventional impregnation method, Sample 2 is the sample in which the external electrode sheet transfer (EEST) method is applied to transfer dry sheet onto the ceramic body, and Samples 3 to 7 are the samples in which the semi-dry impregnation method is applied but the ratio of the thickness T2 of the edge portion of the external electrode to the thickness T1 of the central portion of the external electrode is different.

[0126] Referring to Table 4, in the case of sample 1 prepared by the conventional impregnation method and sample 2 prepared by the EEST method, the thickness ratio (T2 / T1) of the center and edge of the outer electrode is 0.079 and 0.125, respectively, indicating that the edge is relatively thin. As a result, the moisture resistance reliability defect rate is also very high in both cases, at 1667 ppm. Therefore, samples 1 and 2 are identified as defective.

[0127] For samples 3 to 7 prepared by the semi-dry impregnation method, the thickness T1 at the center of the outer electrode is greater than or equal to 10 μm and less than or equal to 15 μm. Samples 3 and 6 show outer electrode thickness ratios (T2 / T1) of 0.367 and 0.258, respectively, which are less than 0.4, and the moisture resistance reliability defect rate is 833 ppm. Therefore, these samples are identified as defective.

[0128] In addition, samples 4, 5 and 7 showed external electrode thickness ratios (T2 / T1) of 0.415, 0.408 and 0.420 respectively, all of which were higher than 0.4, and the moisture resistance reliability defect rate was 0. Therefore, these samples were determined to be good.

[0129] Thus, it can be seen that, compared with the traditional method, the thickness ratio (T2 / T1) of the external electrode is higher in the semi-dry impregnation method, and it can also be seen that the thickness ratio (T2 / T1) of the external electrode must be greater than or equal to 0.4 to avoid poor moisture resistance reliability. In this test example, the thickness ratio (T2 / T1) of the external electrode of samples 4, 5 and 7, which were determined to be good, is greater than or equal to 0.4 and less than or equal to 0.6.

[0130] While this disclosure has been described in conjunction with what is now considered to be actual embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalents included within the spirit and scope of the appended claims.

Claims

1. A multilayer ceramic capacitor, comprising: A ceramic body includes multiple dielectric layers and multiple internal electrodes, wherein the multiple internal electrodes are arranged such that the dielectric layers are disposed between the multiple internal electrodes; as well as The external electrode is arranged on the opposite side of the ceramic body in the first direction. The external electrode includes: A first glass portion is positioned on the first direction end surface of the ceramic body and connected to the inner electrode; and The second glass portion is located on a portion of at least one of the second directional side surface and the third directional side surface of the ceramic body, and contains Fe.

2. The multilayer ceramic capacitor according to claim 1, wherein, The second glass portion contains 5 wt% to 10 wt% Fe.

3. The multilayer ceramic capacitor according to claim 1, wherein, For the external electrode T2 / T1 is greater than or equal to 0.4 and less than or equal to 1, where T1 is the thickness of the external electrode in the first direction at the central portion of the first direction end surface of the ceramic body, and T2 is the thickness of the external electrode at the edge between the first direction end surface of the ceramic body and at least one of the second direction side surface and the third direction side surface.

4. The multilayer ceramic capacitor according to claim 3, wherein, T2 / T1 is greater than or equal to 0.4 and less than or equal to 0.

6.

5. The multilayer ceramic capacitor according to claim 1, wherein, The first glass portion includes a metal containing Cu or Ni, and also includes Ba-based glass or Zn-based glass.

6. The multilayer ceramic capacitor according to claim 1, wherein, The second glass portion includes a metal containing Cu or Ni, and also includes Ba-based glass or Zn-based glass.

7. The multilayer ceramic capacitor according to claim 1 or 6, wherein, The second glass portion includes Fe-based glass, wherein the Fe in the second glass portion is Fe from the Fe-based glass.

8. The multilayer ceramic capacitor according to claim 1, The multilayer ceramic capacitor also includes a plating layer covering the first glass portion and the second glass portion.

9. A multilayer ceramic capacitor, comprising: A ceramic body includes multiple dielectric layers and multiple internal electrodes, wherein the multiple internal electrodes are arranged such that the dielectric layers are disposed between the multiple internal electrodes; as well as The external electrode is arranged on the opposite side of the ceramic body in the first direction. The external electrode comprises both metallic and glass components, and The glass composition of the portion of the external electrode located on at least one of the second directional side surface and the third directional side surface of the ceramic body contains Fe.

10. The multilayer ceramic capacitor according to claim 9, wherein, The external electrode comprises 5 wt% to 10 wt% Fe.

11. The multilayer ceramic capacitor according to claim 9, wherein, For the external electrode T2 / T1 is greater than or equal to 0.4 and less than or equal to 1, where T1 is the thickness of the external electrode at the central portion of the first direction end surface of the ceramic body in the first direction, and T2 is the thickness of the external electrode at the edge between the first direction end surface of the ceramic body and at least one of the second direction side surface and the third direction side surface.

12. The multilayer ceramic capacitor according to claim 11, wherein, T2 / T1 is greater than or equal to 0.4 and less than or equal to 0.

6.

13. The multilayer ceramic capacitor according to claim 9, wherein, The metallic component includes Cu or Ni.

14. The multilayer ceramic capacitor according to claim 9, wherein, The glass composition includes Ba-based glass or Zn-based glass.

15. A multilayer ceramic capacitor, comprising: A ceramic body includes multiple dielectric layers, multiple first internal electrodes, and multiple second internal electrodes, wherein the first internal electrodes and the second internal electrodes are arranged such that the dielectric layers are disposed between the first internal electrodes and the second internal electrodes. as well as The first external electrode and the second external electrode are respectively arranged on opposite sides of the ceramic body in the first direction. The first external electrode includes: A first glass portion, positioned on the first directional end surface of the ceramic body, connected to the first internal electrode, and having Fe; and The second glass portion, located on a portion of at least one of the second directional side surface and the third directional side surface of the ceramic body, has Fe, and the Fe content in the second glass portion is greater than the Fe content in the first glass portion.

16. The multilayer ceramic capacitor according to claim 15, wherein, The second glass portion contains 5 wt% to 10 wt% Fe.

17. The multilayer ceramic capacitor according to claim 15, wherein, For the first external electrode T2 / T1 is greater than or equal to 0.4 and less than or equal to 1, where T1 is the thickness of the first external electrode in the first direction at the central portion of the first direction end surface of the ceramic body, and T2 is the thickness of the first external electrode at the edge between the first direction end surface of the ceramic body and at least one of the second direction side surface and the third direction side surface.

18. The multilayer ceramic capacitor according to claim 17, wherein, T2 / T1 is greater than or equal to 0.4 and less than or equal to 0.

6.

19. The multilayer ceramic capacitor according to claim 15, wherein, The first glass portion includes a metal containing Cu or Ni, and also includes Ba-based glass or Zn-based glass.

20. The multilayer ceramic capacitor according to claim 15, wherein, The second glass portion includes a metal containing Cu or Ni, and also includes Ba-based glass or Zn-based glass.

21. The multilayer ceramic capacitor according to claim 15, wherein, At the edge between the first directional end surface and at least one of the second directional side surface and the third directional side surface of the ceramic body, the Fe content in the first external electrode decreases along the path from the second glass portion to the first glass portion.

22. The multilayer ceramic capacitor according to claim 15 or 20, wherein, The second glass portion includes Fe-based glass, wherein the Fe in the second glass portion is Fe from the Fe-based glass.

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