Multilayer ceramic capacitor

Abstract

This invention provides a multilayer ceramic capacitor that can maintain hermetic sealing while reducing the thickness of the external electrodes. [Solution] The disclosed multilayer ceramic capacitor includes a ceramic body comprising a plurality of dielectric layers and a plurality of internal electrodes arranged sandwiching the dielectric layers, and external electrodes arranged on both sides of the ceramic body in a first direction, wherein the external electrodes include a first glass portion arranged on the end surface of the ceramic body in the first direction and connected to the internal electrodes, and a second glass portion arranged on a part of at least one of the side surfaces in the second and third directions of the ceramic body and containing an iron (Fe) component.

Description

[Technical Field]

[0001] This disclosure relates to multilayer ceramic capacitors. [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, having guaranteed high capacitance, and being easy to mount.

[0003] Multilayer ceramic capacitors are chip-shaped electronic components that are mounted on the substrates of various electronic products such as liquid crystal displays (LCDs), plasma display panels (PDPs), organic light-emitting diodes (OLEDs), computers, personal mobile devices, and smartphones, and play a role in charging or discharging electricity.

[0004] As the operating environments for multilayer ceramic capacitors become more diverse, the moisture resistance reliability of these capacitors is becoming increasingly important.

[0005] A multilayer ceramic capacitor can include internal electrodes located inside the ceramic body and external electrodes located outside the ceramic body and connected to the internal electrodes. To increase the effective capacitance in order to miniaturize and increase the capacitance of a multilayer ceramic capacitor, one approach is to enlarge the size of the ceramic body and minimize the thickness of the external electrodes.

[0006] However, in order to increase the size of the ceramic body, the thickness of the external electrodes is reduced, which can lead to a decrease in the hermetic sealing of the external electrodes, potentially resulting in a reduced moisture resistance reliability of the multilayer ceramic capacitor. [Overview of the project] [Problems that the invention aims to solve]

[0007] One aspect of this embodiment is the provision of a multilayer ceramic capacitor that can ensure hermetic sealing while reducing the thickness of the external electrodes.

[0008] However, the problems that the embodiments of the present invention aim to solve are not limited to those described above, and can be broadly extended within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0009] A multilayer ceramic capacitor according to one embodiment includes a ceramic body containing a plurality of dielectric layers and a plurality of internal electrodes arranged sandwiching the dielectric layers, and external electrodes arranged on both sides of the ceramic body in a first direction, wherein the external electrodes include a first glass portion arranged on the end surface of the ceramic body in the first direction and connected to the internal electrodes, and a second glass portion arranged on a part of at least one of the side surfaces in the second and third directions of the ceramic body and containing an iron (Fe) component.

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

[0011] The external electrode may have a thickness T1 at the center of the end face in the first direction of the ceramic body and a thickness T2 between at least one side surface in the second and third directions of the ceramic body and the end face in the first direction of the ceramic body, where T2 / T1 is 0.4 to 1.

[0012] In this case, T2 / T1 may be between 0.4 and 0.6.

[0013] The first glass portion may include a metal containing copper (Cu) or nickel (Ni) and a barium-based or zinc-based glass.

[0014] The second glass portion may include a metal containing copper (Cu) or nickel (Ni) and a barium-based or zinc-based glass.

[0015] The external electrode may further include a plating layer covering the first glass portion and the second glass portion.

[0016] A multilayer ceramic capacitor according to one embodiment includes a ceramic body containing a plurality of dielectric layers and a plurality of internal electrodes arranged between the dielectric layers, and external electrodes arranged on both sides of the ceramic body in a first direction, wherein the external electrodes contain a metal component and a glass component, and the portion of the external electrodes arranged on a part of at least one side of the ceramic body in the second and third directions may further contain an iron (Fe) component.

[0017] The external electrode may contain 5 wt% to 10 wt% of the iron (Fe) component.

[0018] The external electrode may have a thickness T1 at the center of the end face in the first direction of the ceramic body and a thickness T2 between at least one side surface in the second and third directions of the ceramic body and the end face in the first direction of the ceramic body, where T2 / T1 is 0.4 to 1.

[0019] In this case, T2 / T1 may be between 0.4 and 0.6.

[0020] The aforementioned metal component may be copper (Cu) or nickel (Ni).

[0021] The aforementioned glass component may include Ba-based or Zn-based glass.

Advantages of the Invention

[0022] According to the multilayer ceramic capacitor according to the embodiment, the thickness of the external electrode can be reduced to increase the capacitance of the multilayer ceramic capacitor, and the hermetic sealing of the external electrode can be ensured to improve the moisture resistance reliability of the multilayer ceramic capacitor.

[0023] However, the effects of the embodiments are not limited to the effects described above, and it is obvious that they can be variously extended without departing from the spirit and scope of the present invention.

Brief Description of the Drawings

[0024] [Figure 1] It is a perspective view schematically showing a multilayer ceramic capacitor according to an embodiment. [Figure 2] It is a cross-sectional view taken along the line II-II' of FIG. 1. [Figure 3] It is an enlarged view of part A of FIG. 2. [Figure 4] It is a separated perspective view showing the laminated structure of internal electrodes in the multilayer ceramic capacitor of FIG. 1. [Figure 5] It is a digital image of a part of a multilayer ceramic capacitor according to an embodiment. [Figure 6] It is a digital image of a part of a multilayer ceramic capacitor according to an embodiment. [Figure 7] It is a digital image of a part of a multilayer ceramic capacitor according to a comparative example. [Figure 8] It is a digital image of a part of a multilayer ceramic capacitor according to a comparative example.

Modes for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings, so that those with ordinary skill in the art to which the present invention pertains can easily implement it. In the drawings, parts that are not necessary for the explanation of the present invention have been omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. In addition, some components in the attached drawings are exaggerated, omitted, or shown schematically, and the size of each component does not fully reflect its actual size.

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

[0029] Throughout the specification, terms such as “includes” or “have” are intended to indicate 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 possibility of the presence or addition of one or more other features, figures, stages, operations, components, parts, or combinations thereof. Therefore, when a part “includes” a component, this means, unless otherwise stated, that it may further include other components rather than excluding them.

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

[0031] Furthermore, throughout the specification, when we use the term "connected," it 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, even though they are referred to by different names depending on their location or function.

[0032] Figure 1 is a schematic perspective view of a multilayer ceramic capacitor according to one embodiment; Figure 2 is a cross-sectional view along the line II-II' in Figure 1; Figure 3 is an enlarged view of portion A in Figure 2; Figure 4 is a separated perspective view showing the layered structure of the internal electrodes in the multilayer ceramic capacitor of Figure 1; Figure 5 is a digital image of a part of the multilayer ceramic capacitor according to one embodiment; and Figure 6 is a digital image of a part of the multilayer ceramic capacitor according to one embodiment.

[0033] Referring to Figures 1 to 6, the multilayer ceramic capacitor 100 according to this embodiment includes 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.

[0034] First, to clearly explain this embodiment, the directions are defined as follows: the L-axis, W-axis, and T-axis shown in the drawing refer to the axes indicating the length, width, and thickness directions of the multilayer ceramic capacitor 100, respectively.

[0035] The thickness direction (T-axis direction) may be perpendicular to the broad surface (main surface) of the sheet-shaped component. For example, the thickness direction (T-axis direction) can be used with the same concept as the direction in which the dielectric layer 140 is stacked.

[0036] The length direction (L-axis direction) is parallel to the broad surface (main surface) of the sheet-shaped component and may intersect (or be perpendicular to) the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be the direction in which the first external electrode 120 and the second external electrode 130 face each other.

[0037] The width direction (W-axis direction) is a direction parallel to the wide surface (main surface) of the sheet-shaped component, and may simultaneously intersect (or be perpendicular to) the thickness direction (T-axis direction) and the length direction (L-axis direction).

[0038] The ceramic body 110 may have a substantially hexahedral shape, but this embodiment is not limited to this. Due to shrinkage during sintering, the ceramic body 110 may not have a perfect hexahedral shape, but may have a substantially hexahedral shape. For example, the ceramic body 110 may have a substantially rectangular parallelepiped shape, but the parts corresponding to the corners and vertices may have a rounded shape.

[0039] In this embodiment, for the sake of explanation, surfaces facing each other in the length direction (L-axis direction) are defined as the end surface in the length direction or the first surface S1 and the second surface S2; surfaces facing each other in the width direction (W-axis direction) and connecting the first surface S1 and the second surface S2 are defined as the side surface in the width direction or the third surface S3 and the fourth surface S4; and surfaces facing each other in the thickness direction (T-axis direction) and connecting the first surface S1 and the second surface S2 are defined as the side surface in the thickness direction or the fifth surface S5 and the sixth surface S6.

[0040] Therefore, the first direction, which is the direction in which the first surface S1 and the second surface S2 face each other, may be the length direction (L-axis direction), and the second and third directions, which are perpendicular to the first direction and perpendicular to each other, may 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), respectively.

[0041] Furthermore, the area between the end face in the longitudinal direction and the side surface in the thickness or width direction of the ceramic body 110 will be defined as a corner. In other words, the curved portion between the third face S3 to the sixth face S6 and the first face S1 can be called the first corner C1, and the curved portion between the third face S3 to the sixth face S6 and the second face S2 can be called the second corner C2.

[0042] The length of the ceramic body 110 can be defined as the maximum length among multiple line segments parallel to the length direction (L-axis direction), obtained by connecting the two outermost boundary lines of the ceramic body 110 that are opposite each other in the length direction (L-axis direction) as seen in the aforementioned cross-sectional photograph of the ceramic body 110 in the width direction (W-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the cross-sectional photograph of the ceramic body 110 in the length direction (L-axis direction). Alternatively, the length of the ceramic body 110 can be defined as the minimum length among multiple line segments parallel to the length direction (L-axis direction), obtained by connecting the two outermost boundary lines of the ceramic body 110 that are opposite each other in the length direction (L-axis direction), as seen in the aforementioned cross-sectional photograph. Alternatively, the length of the ceramic body 110 can be defined as the arithmetic mean of the lengths of at least two line segments parallel to the length direction (L-axis direction), obtained by connecting the two outermost boundary lines of the ceramic body 110 that are opposite each other in the length direction (L-axis direction), as seen in the aforementioned cross-sectional photograph.

[0043] The thickness of the ceramic body 110 can be defined as the maximum length of a plurality of line segments parallel to the thickness direction (T-axis direction), obtained by connecting the two outermost boundary lines that appear in the aforementioned cross-sectional photograph of the ceramic body 110 in the thickness direction (T-axis direction) at the center of the ceramic body 110 in the width direction (W-axis direction), using an optical microscope or scanning electron microscope (SEM) photograph as a reference. Alternatively, the thickness of the ceramic body 110 can be defined as the minimum length of a plurality of line segments parallel to the thickness direction (T-axis direction), obtained by connecting the two outermost boundary lines that appear in the aforementioned cross-sectional photograph of the ceramic body 110 in the thickness direction (T-axis direction). Alternatively, the thickness of the ceramic body 110 can be defined as the arithmetic mean of the lengths of at least two line segments parallel to the thickness direction (T-axis direction), obtained by connecting the two outermost boundary lines that appear in the aforementioned cross-sectional photograph of the ceramic body 110 in the thickness direction (T-axis direction).

[0044] The width of the ceramic body 110 can be defined as the maximum length of a plurality of line segments parallel to the width direction (W-axis direction), obtained by connecting the two outermost boundary lines of the ceramic body 110 that are opposite each other in the width direction (W-axis direction) as shown in the aforementioned cross-sectional photograph of the ceramic body 110 in the central part in the thickness direction (T-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the cross-sectional photograph of the ceramic body 110 in the length direction (L-axis direction) - width direction (W-axis direction). Alternatively, the width of the ceramic body 110 can be defined as the minimum length of a plurality of line segments parallel to the width direction (W-axis direction), obtained by connecting the two outermost boundary lines of the ceramic body 110 that are opposite each other in the width direction (W-axis direction) as shown in the aforementioned cross-sectional photograph. Alternatively, the width of the ceramic body 110 can be defined as the arithmetic mean of the lengths of at least two line segments parallel to the width direction (W-axis direction), obtained by connecting the two outermost boundary lines of the ceramic body 110 that are opposite each other in the width direction (W-axis direction) as shown in the aforementioned cross-sectional photograph.

[0045] The ceramic body 110 may include multiple dielectric layers 140 stacked in the thickness direction (T-axis direction). The boundaries between the dielectric layers 140 may be unclear. For example, the boundaries between the dielectric layers 140 may be difficult to confirm without using a scanning electron microscope (SEM), and the multiple dielectric layers 140 may appear as a single structure.

[0046] The first internal electrode 150 and the second internal electrode 160 can be stacked alternately with the dielectric layer 140 in between. Such a stacked structure can be repeated within the ceramic body 110, and the internal electrode closest to the fifth surface S5 of the ceramic body 110 may be either the first internal electrode 150 or the second internal electrode 160, and the internal electrode closest to the sixth surface S6 may also be either the first internal electrode 150 or the second internal electrode 160.

[0047] The first internal electrode 150 and the second internal electrode 160 have different polarities, but they can be electrically insulated from each other by the dielectric layer 140 placed between them.

[0048] The first internal electrode 150 and the second internal electrode 160 may be arranged so as to be offset from each other in the longitudinal direction (L-axis direction) with respect to the dielectric layer 140. One end of the first internal electrode 150 can be exposed through the first surface S1 of the ceramic body 110, and one end of the second internal electrode 160 can be exposed through the second surface S2 of the ceramic body 110. The end of the first internal electrode 150 exposed from the first surface S1 of the ceramic body 110 can be connected to the first external electrode 120. The end of the second internal electrode 160 exposed from the second surface S2 of the ceramic body 110 can be connected to the second external electrode 130.

[0049] The first internal electrode 150 and the second internal electrode 160 may be formed by printing a conductive paste containing a conductive metal onto the surface of the dielectric layer 140. For example, the internal electrodes can be formed by printing a conductive paste containing nickel (Ni) or a nickel (Ni) alloy onto the surface of the dielectric layer using screen printing or gravure printing. However, this embodiment is not limited to this.

[0050] For example, the average thickness of the first internal electrode 150 and the second internal electrode 160 may be approximately 0.1 μm or more and 2 μm or less.

[0051] Here, the thickness of the internal electrode can refer to the average thickness of one internal electrode placed between two dielectric layers. The average thickness of the internal electrode may also be the arithmetic mean of the thickness of one internal electrode shown in a scanning electron microscope (SEM) photograph taken at a magnification of 10,000x for a cross section in the length direction (L direction) - thickness direction (T direction) at the center of the ceramic body 110 in the width direction (W direction), measured at 30 points evenly spaced in the length direction (L direction). These 30 points can be specified in the active region described later. After measuring the average thickness of 10 internal electrodes in this manner, the average thickness of the internal electrode can be further generalized by deriving the arithmetic mean of the measured values.

[0052] 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. In other words, 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 overlapping area of ​​the first internal electrode 150 and the second internal electrode 160, which are superimposed on each other along the thickness direction (T-axis direction).

[0053] In other words, the multilayer ceramic capacitor 100 may include an active region and a margin region. The active region may refer to the region in which the first internal electrode 150 and the second internal electrode 160 overlap along the thickness direction (T-axis direction), and the margin region may refer to the region between the active region and the first surface S1 of the ceramic body 110, and the region between the active region and the second surface S2 of the ceramic body 110.

[0054] Multilayer ceramic capacitors 100 are classified based on their length and width. Therefore, even multilayer ceramic capacitors with the same length and width may have different ceramic body sizes depending on the thickness of their external electrodes. In other words, a multilayer ceramic capacitor with thinner external electrodes can have a larger ceramic body than one with thicker external electrodes. A larger ceramic body means a larger active region, and consequently, a larger capacitance. In short, the thinner the external electrodes of a multilayer ceramic capacitor, the greater the capacitance. In this embodiment, by forming thin electrode layers on the first and second surfaces of the ceramic body, the thickness of the external electrodes can be reduced, and advantageous effects can be obtained as a result. This will be explained in more detail below.

[0055] A first cover layer 143 and a second cover layer 145 may be arranged on the outside of the active region in the thickness direction (T-axis direction).

[0056] The first cover layer 143 is positioned between the fifth surface S5 of the ceramic body 110 and the internal electrode closest to it. The second cover layer 145 is positioned between the sixth surface S6 of the ceramic body 110 and the internal electrode closest to it.

[0057] That is, a first cover layer 143 may be disposed above the internal electrode at the uppermost part within the ceramic body 110, and a second cover layer 145 may be disposed below the internal electrode at the lowermost part. The first cover layer 143 and the second cover layer 145 can have the same composition as the dielectric layer 140. One or more dielectric layers can be laminated on the outer surfaces of the uppermost internal electrode and the lowermost internal electrode, respectively, to form the first cover layer 143 and the second cover layer 145.

[0058] The first cover layer 143 and the second cover layer 145 can serve to prevent damage to the first internal electrode 150 and the second internal electrode 160 due to physical or chemical stress.

[0059] The dielectric layer 140 can include a high dielectric constant ceramic material. For example, the ceramic material can include a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. Further, these components can further include auxiliary components such as manganese (Mn) compounds, iron (Fe) compounds, chromium (Cr) compounds, cobalt (Co) compounds, nickel (Ni) compounds, etc. For example, the dielectric layer is (Ba y Ca x )TiO3, Ba(Ti 1-y Ca y )O3, (Ba 1-x Ca x )(Ti 1-y ​​​​​​​​​​​​​​For example, the average thickness of the dielectric layer 140 may be 0.1 μm to 10 μm, but this embodiment is not limited to this.

[0062] 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 also be positioned on both sides of the ceramic body 110 in the first direction.

[0063] The first external electrode 120 is positioned on the first surface S1 of the ceramic body 110 and can extend to at least one of the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6. The second external electrode 130 is positioned on the second surface S2 of the ceramic body 110 and can extend to at least one of the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6.

[0064] The first external electrode 120 may include a metal and a glass. Here, the metal may include, for example, copper (Cu) or nickel (Ni), and the glass may include an oxide glass.

[0065] The first external electrode 120 includes a first glass portion 121 and a second glass portion 123.

[0066] The first glass portion 121 is positioned on the first surface S1 of the ceramic body 110 and is electrically connected to the exposed ends of the multiple first internal electrodes 150.

[0067] The first glass portion 121 may include a metal and glass. Here, the metal may include, for example, copper (Cu) or nickel (Ni), and the glass may include Ba-based or Zn-based glass, etc.

[0068] The first glass portion 121 can be formed by a semi-dry dipping method. Specifically, a paste containing a conductive metal and glass is semi-dried on the first surface S1 of the ceramic body 110, then applied and dried, and subsequently formed by a heat treatment called electrode firing.

[0069] Referring to Figure 5, it can be seen that the center of the first glass portion 121 is almost flat, and referring to Figure 6, it can be seen that the thickness of the first external electrode 120 is ensured to be above a certain level between the fifth surface S5 and the first surface S1 of the ceramic body 110 (first corner C1).

[0070] Unlike this embodiment, in the case of a general dipping method in which a high-viscosity paste is applied to the first surface S1 of the ceramic body 110, dried, and then heat-treated, capillary bridges are formed due to the high viscosity of the paste, and leveling is not performed. As a result, even after electrode sintering, the central part of the external electrode bulges, the corners become thinner, increasing the thickness of the external electrode and potentially leading to a problem where hermetic sealing cannot be ensured.

[0071] In contrast, according to this embodiment, by partially drying a paste containing metal and glass, then applying, drying, and heat-treating it to form the first glass portion, the thickness of the external electrode can be minimized, the effective capacity can be increased, and sufficient hermetic sealing of the external electrode can be ensured.

[0072] On the other hand, the first glass portion 121 is a portion for electrical connection with the internal electrodes and may be arranged on the first surface S1 of the ceramic body 110, or it may be arranged so as to cover the exposed ends of the multiple first internal electrodes 150 from the first surface S1 of the ceramic body 110.

[0073] The second glass portion 123 is positioned on a part of at least one of the third, fourth, fifth, and sixth surfaces S3, S4, S5, and S6 of the ceramic body 110, and may include metal and glass. Here, the metal may include metals such as copper (Cu) or nickel (Ni), and the glass may include Ba-based glass, Zn-based glass, Fe-based glass, etc.

[0074] The second glass section 123 contains Fe-based glass in addition to Ba-based and Zn-based glass components, so by imparting corrosion resistance with a plating solution, the hermetic sealing can be strengthened, thereby improving plating cracking and moisture resistance reliability.

[0075] The second glass portion 123 may contain 5 wt% to 10 wt% of iron (Fe) component. If the iron (Fe) component is 5 wt% or more, a corrosion-resistant glass effect will occur, and if it exceeds 10 wt%, excessive glass sintering may reduce wettability with the metal and cause glass to dissolve, which may lead to plating cracking and a decrease in moisture resistance reliability.

[0076] The second glass portion 123 can be formed by dipping both sides of the ceramic body 110, on which the first glass portion 121 is formed, in a paste containing metal and glass, and then blotting this paste onto a PMP (Porous Material Plate) to remove the paste applied to the outer surface of the first glass portion 121. Therefore, the second glass portion 123 is located on a part 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 is not located on the outer surface of the first glass portion 121.

[0077] One end of the second glass portion 123 may be in contact with the first glass portion 121, and the other end 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 towards both ends.

[0078] The second glass portion 123 can come into contact with the first glass portion 121 at the space between at least one of the third, fourth, fifth, and sixth surfaces S3, fourth, fifth, and sixth surfaces S6 of the ceramic body 110 and the first surface S1 (first corner C1). Since the first glass portion 121 and the second glass portion 123 are all composed of metal and glass as elements constituting the first external electrode 120, their boundary can be ambiguous.

[0079] The first external electrode 120 may have a T2 / T1 ratio of 0.4 to 1, where T1 is the thickness at the center of the first surface S1 of the ceramic body 110, and T2 is the thickness between at least one of the third, fourth, fifth, and sixth surfaces S3, fourth, fifth, and sixth surfaces S6 of the ceramic body 110 and the first surface S1 (first corner C1). Here, thickness T1 refers to the thickness at the center of the first glass portion 121, and the thickness of the first glass portion 121 can be measured within a certain range based on the center point of the first surface S1 of the ceramic body 110, with the maximum thickness being determined as T1. T2 refers to the thickness of the portion where the first glass portion 121 and the second glass portion 123 are in contact, and a reference line can be set at a 45-degree angle from the first corner C1 of the ceramic body 110, and the thickness within a certain range along this reference line can be measured, with the minimum thickness being determined as T2.

[0080] If the thickness ratio (T2 / T1) of the first external electrode 120 is less than 0.4, a problem occurs in which the moisture resistance reliability decreases; therefore, the thickness ratio (T2 / T1) of the first external electrode 120 must be 0.4 or greater. Furthermore, when the external electrode is formed using a dipping method with a paste containing metal and glass, the central part of the external electrode is formed thicker than the outer part, so the thickness ratio (T2 / T1) of the first external electrode 120 cannot exceed 1.

[0081] The second external electrode 130 includes a third glass portion 131 and a fourth glass portion 133.

[0082] The third glass portion 131 is positioned on the second surface S2 of the ceramic body 110 and is electrically connected to the exposed ends of the multiple second internal electrodes 160.

[0083] The fourth glass portion 133 is positioned on a part 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 may include metal and glass. The fourth glass portion 133 may include Fe-based glass as its glass component.

[0084] Since the second external electrode 130 corresponds to the structure, material, and function of the first external electrode 120, except for its position, a repeated explanation of it will be omitted.

[0085] On the other hand, the multilayer ceramic capacitor 100 may further include a first plating layer 180 and a second plating layer 190.

[0086] The first plating layer 180 covers 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 placed on the first external electrode 120, and the second layer 183 may be placed on the first layer 181. The first layer 181 may contain nickel (Ni), and the second layer 183 may contain tin (Sn), but this embodiment is not limited thereto.

[0087] The second plating layer 190 covers 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 placed on the second external electrode 130, and the second layer 193 may be placed on the first layer 191. The first layer 191 may contain nickel (Ni), and the second layer 193 may contain tin (Sn), but this embodiment is not limited thereto.

[0088] Experimental Example 1 The plating cracking and moisture resistance reliability of the examples and comparative examples 1 and 2 will be described below with reference to Figures 7 and 8 and Table 1.

[0089] Figure 7 is a digital image of a portion of the multilayer ceramic capacitor according to Comparative Example 1, Figure 8 is a digital image of a portion of the multilayer ceramic capacitor according to Comparative Example 2, and Table 1 is a table showing the capacitance contact, plating cracking, and moisture resistance reliability of the example and Comparative Examples 1 and 2.

[0090] [Table 1]

[0091] In Table 1, the example is a multilayer ceramic capacitor in which the external electrodes, positioned outside the ceramic body, have the structure shown in Figures 1 to 4.

[0092] Comparative Example 1 is a multilayer ceramic capacitor in which the entire external electrode is formed from a conventional conductive paste, while Comparative Example 2 is a multilayer ceramic capacitor in which the entire external electrode is formed from a corrosion-resistant paste further containing iron (Fe).

[0093] Referring to Table 1, in Comparative Example 1, capacitive contact was good and end-face plating cracking was 0%, but apex plating cracking was 30%, and the moisture resistance degradation characteristic was high at 13333 ppm. Here, capacitive contact indicates the electrical connection between the internal electrode and the external electrode, the end-face refers to the first or second surface of the ceramic body, and the apex refers to the point where the first or second surface of the ceramic body meets two adjacent surfaces from the third to sixth surfaces. Referring to Figure 7, it can be seen that in Comparative Example 1, plating cracking occurs at the apex. Here, plating cracking can be measured by removing Sn from the external electrode on which the Ni-Sn plating layer is formed using an Sn stripping solution etching solution, and then observing whether there is any Ni plating cracking using a scanning electron microscope (SEM).

[0094] In Comparative Example 2, while there was 0% plating cracking at the apex, the capacitive contact was poor, 60% of the end face plating cracking occurred, and the moisture resistance degradation characteristic was high at 18333 ppm. Referring to Figure 8, it can be seen that in Comparative Example 2, plating cracking occurred at the end face. From this, it can be seen that applying corrosion-resistant paste to the end face results in poor capacitive contact and a significant decrease in moisture resistance reliability.

[0095] In contrast, in the example where a glass portion containing metal and glass is arranged on the longitudinal end face of the ceramic body as an external electrode, and a glass portion further containing iron (Fe) is arranged on the thickness or width side surface of the ceramic body, capacitive contact was good, with 0% plating cracking at the end face, 0% plating cracking at the apex, and 0 ppm of moisture degradation characteristics. Therefore, it can be confirmed that the capacitive contact and moisture resistance reliability were significantly improved compared to Comparative Examples 1 and 2.

[0096] Experimental Example 2 The following describes the moisture resistance reliability and other defects for various samples, depending on the iron (Fe) content of the glass portion (hereinafter referred to as "second glass portion and fourth glass portion") located on the side surface in the thickness or width direction of the ceramic body of the external electrode, with reference to Table 2.

[0097] Table 2 shows the characteristics, such as humidity resistance reliability, for samples with different iron (Fe) content in the second and fourth glass portions of the external electrode.

[0098] [Table 2]

[0099] In Table 2, samples 1, 2, 6, and 7 are multilayer ceramic capacitors according to comparative examples, while samples 3 to 5 are multilayer ceramic capacitors according to examples.

[0100] Referring to Table 2, in the case of samples 1 and 2, where the iron (Fe) content in the second and fourth glass sections was less than 5 wt%, the plating solution penetration frequency was 55% and 2%, respectively, and the moisture resistance reliability was poor at 18333 ppm and 13333 ppm, respectively. Both samples were defective due to cracking at the apex of the Ni plating layer. From this, it can be confirmed that the corrosion resistance effect does not occur when the iron (Fe) content is less than 5 wt%.

[0101] 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 penetration frequency of the plating solution was 0% in all cases. However, the humidity resistance reliability was poor at 1666 ppm and 2500 ppm, respectively, and both samples failed due to plating cracking caused by glass elution. From this, it can be confirmed that when the iron (Fe) content exceeds 10 wt%, excessive glass sintering reduces wettability with the metal, causing glass elution, which leads to plating cracking and a decrease in humidity resistance reliability.

[0102] In contrast, in the case of samples 3, 4, and 5, where the iron (Fe) content of the second and fourth glass portions was 5 wt% to 10 wt%, the penetration frequency of the plating solution was 0% in all cases, the humidity resistance reliability was 0 ppm in all cases, and no other defects appeared. Therefore, it can be seen that the iron (Fe) content of the second and fourth glass portions of the external electrode is preferably 5 wt% to 10 wt%.

[0103] Experimental Example 3 The moisture resistance reliability for various samples, according to the ratio of the thickness T1 at the center of the external electrode to the thickness T2 at the corners, will be explained below with reference to Table 3.

[0104] Table 3 shows the moisture resistance reliability of various samples of the 0603 type multilayer ceramic capacitor, according to the thickness ratio between the center and corners of the external electrodes.

[0105] [Table 3]

[0106] In Table 3, Sample 1 is a sample in which the external electrode was formed by a conventional dipping method, Sample 2 is a sample to which the EEST (External Electrode Sheet Transition) method, in which a dried sheet is transferred to the ceramic body, and Samples 3 to 7 are samples to which the semi-dried dipping method is applied, but the thickness of the central and corner parts of the external electrode differs.

[0107] As shown in Table 3, in the case of sample 1, which was prepared using the conventional dipping method, and sample 2, which was prepared using the EEST method, the thickness ratio (T2 / T1) of the central part to the corner of the external electrode was 0.05 and 0.1, respectively. The thickness of the corner was relatively very thin, which resulted in very high humidity resistance reliability of 15833 ppm and 7500 ppm, respectively, and thus the samples were deemed unsuccessful.

[0108] In the case of samples 3 and 4, which were produced using the semi-dry dipping method, the thickness T1 of the central part of the external electrode was the same at 10 μm, while the thickness T2 of the corners was 3.6 μm and 4.2 μm, respectively, resulting in an external electrode thickness ratio (T2 / T1) of 0.36 and 0.42, respectively. In the case of sample 4, where the external electrode thickness ratio (T2 / T1) was 0.4 or higher, the moisture resistance reliability failure was 0 and it was judged to be a good product. However, in the case of sample 3, where the external electrode thickness ratio (T2 / T1) was less than 0.4, the moisture resistance reliability failure was 833 ppm and it was judged to be a failure.

[0109] In the case of samples 5 and 6, which were produced using the semi-dry dipping method, the thickness T1 of the central part of the external electrode was the same at 9 μm, while the thickness T2 of the corners was 3 μm and 4.1 μm, respectively, resulting in external electrode thickness ratios (T2 / T1) of 0.33 and 0.46, respectively. In the case of sample 6, where the external electrode thickness ratio (T2 / T1) was 0.4 or higher, the moisture resistance reliability failure was 0 and it was judged to be a good product. However, in the case of sample 5, where the external electrode thickness ratio (T2 / T1) was less than 0.4, the moisture resistance reliability failure was 833 ppm and it was judged to be a failure.

[0110] In the case of sample 7, which was produced using the semi-dry dipping method, the thickness T1 of the central part of the external electrode was 8 μm, and the thickness T2 of the corner part was 4.2 μm. The thickness ratio of the external electrode (T2 / T1) was 0.53, which was the highest among the samples in this experiment. Sample 7 had an external electrode thickness ratio (T2 / T1) of 0.4 or higher, and there were no moisture resistance reliability defects, so it was judged to be a good product.

[0111] Thus, it was found that the thickness ratio of the external electrode (T2 / T1) is higher when using the semi-dry dipping method compared to the conventional method, and that moisture resistance reliability defects do not occur unless the thickness ratio of the external electrode (T2 / T1) is 0.4 or higher. In this experimental example, for samples 4, 6, and 7 which were judged to be good products, the thickness ratio of the external electrode (T2 / T1) was between 0.4 and 0.6.

[0112] Experimental Example 4 The moisture resistance reliability for various samples, depending on the ratio of the thickness T1 at the center of the external electrode to the thickness T2 at the corners, will be explained below with reference to Table 4.

[0113] Table 4 shows the moisture resistance reliability of various samples of type 1005 multilayer ceramic capacitors, according to the thickness ratio between the center and corners of the external electrodes.

[0114] [Table 4]

[0115] In Table 4, Sample 1 is a sample in which the external electrode was formed by a conventional dipping method, Sample 2 is a sample to which the EEST (External Electrode Sheet Transition) method, in which a dried sheet is transferred to the ceramic body, and Samples 3 to 7 are samples to which the semi-dried dipping method is applied, but the thickness of the central and corner parts of the external electrode differs.

[0116] Referring to Table 4, in the case of sample 1, which was prepared using the conventional dipping method, and sample 2, which was prepared using the EEST method, the thickness ratio (T2 / T1) of the central part to the corner of the external electrode was 0.079 and 0.125, respectively. The thickness of the corner was relatively very thin, and as a result, the moisture resistance reliability was very high at 1667 ppm in all cases, resulting in a failure.

[0117] For samples 3 to 7, which were formed using the semi-dry dipping method, the experiment was conducted by forming the outer electrode so that the thickness T1 of the central part decreased from 15 μm to 1 μm in increments. Samples 3 and 6 had outer electrode thickness ratios (T2 / T1) of 0.367 and 0.258, respectively, which were less than 0.4, and these samples were judged to have poor moisture resistance reliability at 833 ppm.

[0118] On the other hand, samples 4, 5, and 7 all had external electrode thickness ratios (T2 / T1) of 0.415, 0.408, and 0.420, respectively, all of which were 0.4 or higher. As a result, these samples were judged to be good products with zero moisture resistance reliability defects.

[0119] Thus, it was found that the thickness ratio of the external electrode (T2 / T1) is higher when using the semi-dry dipping method compared to the conventional method, and that moisture resistance reliability defects do not occur unless the thickness ratio of the external electrode (T2 / T1) is 0.4 or higher. In this experimental example, for samples 4, 5, and 7 which were judged to be good products, the thickness ratio of the external electrode (T2 / T1) was between 0.4 and 0.6.

[0120] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, description of the invention, and attached drawings, and it goes without saying that these also fall within the scope of the present invention. [Explanation of Symbols]

[0121] 100: Multilayer ceramic capacitor 110: Ceramic body 120: 1st external electrode 121: First glass section 123: Second glass section 130: 2nd external electrode 131: Third glass section 133: Fourth glass section 140: Dielectric layer 143: First Cover Layer 145: Second Cover Layer 150: 1st internal electrode 160:Second internal electrode 180: First plating layer 190: Second plating layer 181, 191: 1st layer 183, 193: 2nd layer C1: 1st corner C2:Second corner S1: 1st page S2: 2nd side S3:Side 3 S4:Side 4 S5:Side 5 S6:Side 6

Claims

1. A ceramic body including multiple dielectric layers and multiple internal electrodes arranged between the dielectric layers, The ceramic body includes external electrodes arranged on both sides in the first direction, The aforementioned external electrode is A first glass portion is arranged on the end surface in the first direction of the ceramic body and connected to the internal electrode, A multilayer ceramic capacitor comprising a second glass portion containing iron (Fe) and disposed on a portion of at least one of the sides of the ceramic body in a second and third direction.

2. The multilayer ceramic capacitor according to claim 1, wherein the second glass portion contains 5 wt% to 10 wt% of the iron (Fe) component.

3. The aforementioned external electrode is The thickness T1 at the center of the end face in the first direction of the ceramic body, With respect to the thickness T2 between at least one of the side surfaces of the ceramic body in the second and third directions and the end face of the ceramic body in the first direction, The multilayer ceramic capacitor according to claim 1, wherein T2 / T1 is 0.4 or more and 1 or less.

4. The multilayer ceramic capacitor according to claim 3, wherein the T2 / T1 is 0.4 or more and 0.6 or less.

5. The multilayer ceramic capacitor according to claim 1, wherein the first glass portion comprises a metal containing copper (Cu) or nickel (Ni) and a Ba-based glass or a Zn-based glass.

6. The multilayer ceramic capacitor according to claim 1, wherein the second glass portion comprises a metal containing copper (Cu) or nickel (Ni) and a Ba-based glass or a Zn-based glass.

7. The multilayer ceramic capacitor according to claim 1, wherein the external electrode further includes a plating layer covering the first glass portion and the second glass portion.

8. A ceramic body including multiple dielectric layers and multiple internal electrodes arranged between the dielectric layers, The ceramic body includes external electrodes arranged on both sides in the first direction, The external electrode comprises a metal component and a glass component. A multilayer ceramic capacitor wherein the portion of the external electrode that is disposed on a part of at least one of the side surfaces in the second and third directions of the ceramic body further contains an iron (Fe) component.

9. The multilayer ceramic capacitor according to claim 8, wherein the external electrode contains the iron (Fe) component in an amount of 5 wt% or more and 10 wt% or less.

10. The aforementioned external electrode is The thickness T1 at the center of the end face in the first direction of the ceramic body, With respect to the thickness T2 between at least one side surface of the ceramic body in the second and third directions and the end face of the ceramic body in the first direction, The multilayer ceramic capacitor according to claim 8, wherein T2 / T1 is 0.4 or more and 1 or less.

11. The multilayer ceramic capacitor according to claim 10, wherein the T2 / T1 is 0.4 or more and 0.6 or less.

12. The multilayer ceramic capacitor according to claim 8, wherein the metal component is copper (Cu) or nickel (Ni).

13. The multilayer ceramic capacitor according to claim 8, wherein the glass component includes Ba-based glass or Zn-based glass.

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