Multilayer ceramic capacitor

Abstract

To provide a multilayer ceramic capacitor that suppresses the penetration of moisture into the ceramic main body and improves the moisture resistance reliability.SOLUTION: The disclosed multilayer ceramic capacitor includes: a ceramic main body including a first surface and a second surface facing in a first direction, a third surface and a fourth surface facing in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface facing in a third direction and connecting the first surface and the second surface; an internal electrode disposed inside the ceramic main body; a protective layer disposed on the third surface and the fourth surface of the ceramic main body; and a connection electrode covering the protective layer. The protective layer includes: a first protective layer disposed on the third surface and a second protective layer disposed on the fourth surface, and has openings located in the third surface and the fourth surface.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a multilayer ceramic capacitor. [Background technology]

[0002] In recent years, with the trend toward miniaturization of electronic products, multilayer ceramic capacitors are also required to be smaller and have larger capacitance. In response to the demand for miniaturization and larger capacitance of multilayer ceramic capacitors, the external electrodes of the multilayer ceramic capacitors are also being made thinner.

[0003] The paste that forms the external electrodes uses copper (Cu) or other conductive metals as its main material to ensure airtightness and electrical connection with the ceramic body, and glass as an auxiliary material to fill voids caused by sintering shrinkage of the conductive metal and to provide bonding strength between the external electrodes and the ceramic body.

[0004] Multilayer ceramic capacitors are classified based on their length and width. Therefore, even if two multilayer ceramic capacitors have the same length and width, the size of the ceramic body may change depending on the thickness of the external electrodes, which may change the capacitance. Therefore, to increase the capacitance while maintaining the length and width, it is necessary to manufacture the external electrodes thin, but if the external electrodes are thin, there is a higher risk of moisture penetrating into the ceramic body. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of one aspect of the embodiment is to provide a multilayer ceramic capacitor that suppresses moisture penetration into the ceramic body and improves moisture resistance reliability.

[0006] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and may be expanded in various ways within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0007] A multilayer ceramic capacitor according to one embodiment includes a ceramic body including a first surface and a second surface facing in a first direction, a third surface and a fourth surface facing in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface facing in a third direction and connecting the first surface and the second surface, an internal electrode disposed inside the ceramic body, a protective layer disposed on the third surface and the fourth surface of the ceramic body, and a connection electrode covering the protective layer, the protective layer including a first protective layer disposed on the third surface and a second protective layer disposed on the fourth surface, and having openings located on the third surface and the fourth surface.

[0008] The first protective layer and the second protective layer may include portions that extend onto the first surface and the second surface, respectively.

[0009] The internal electrode can be connected to the connection electrode through the opening.

[0010] The protective layer may include silicon (Si) oxide.

[0011] The protective layer has an electrical conductivity of 10 -7 It can be smaller than S / cm.

[0012] The protective layer may include sodium oxide (Na2O).

[0013] The protective layer can include copper(II) oxide (CuO).

[0014] The connection electrode may include particles of the same material as the protective layer.

[0015] The connection electrode includes a first connection electrode at least partially covering the first protective layer and a second connection electrode at least partially covering the second protective layer, the first protective layer having a portion on the first surface and the second surface of the ceramic body that protrudes more than the first connection electrode in the fourth surface direction, and the second protective layer having a portion on the first surface and the second surface of the ceramic body that protrudes more than the second connection electrode in the third surface direction.

[0016] The multilayer ceramic capacitor may further include a first plating electrode at least partially covering the first connection electrode and a second plating electrode at least partially covering the second connection electrode, the first protective layer having a portion on the first surface and the second surface of the ceramic body that protrudes more than the first plating electrode in the fourth surface direction, and the second protective layer having a portion on the first surface and the second surface of the ceramic body that protrudes more than the second plating electrode in the third surface direction.

[0017] The first protective layer and the second protective layer may have portions in contact with the ceramic body.

[0018] A multilayer ceramic capacitor according to another embodiment includes a ceramic body including a first surface and a second surface facing in a first direction, a third surface and a fourth surface facing in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface facing in a third direction and connecting the first surface and the second surface, an internal electrode disposed inside the ceramic body, a protective layer disposed on a portion of the third surface and a portion of the fourth surface of the ceramic body, and a connection electrode covering the protective layer, the connection electrode including a portion that contacts the internal electrode via a portion of the third surface and the fourth surface of the ceramic body where the protective layer is not located.

[0019] The protective layer may include a portion that extends onto the first side and the second side.

[0020] An opening is formed on the third surface and the fourth surface of the ceramic body in a portion where the protective layer is not located, and the protective layer may have a portion that extends continuously from an end on the first surface or the second surface to another end located on one side of the opening.

[0021] The protective layer may include a first protective layer extending along the first surface, the third surface, and the second surface, and a second protective layer extending along the first surface, the fourth surface, and the second surface, the connection electrode may include a first connection electrode covering the first protective layer and a second connection electrode covering the second protective layer, the first protective layer may have a portion on the first surface and the second surface that protrudes further in the fourth surface direction than the first connection electrode, and the second protective layer may have a portion on the first surface and the second surface that protrudes further in the third surface direction than the second connection electrode.

[0022] The semiconductor device may further include a first plating electrode covering the first connection electrode and a second plating electrode covering the second connection electrode, wherein the first protective layer has a portion on the first surface and the second surface that protrudes further in the fourth surface direction than the first plating electrode, and the second protective layer has a portion on the first surface and the second surface that protrudes further in the third surface direction than the second plating electrode. Effect of the Invention

[0023] According to the multilayer ceramic capacitor of the embodiment, even when the external electrodes are formed thin, it is possible to suppress the penetration of moisture into the ceramic body.

[0024] In addition, defects such as the external electrodes falling off during firing of the external electrodes and defects such as plating seeping into unnecessary portions of the ceramic body during formation of plated electrodes can be improved. [Brief description of the drawings]

[0025] [Figure 1] 1 is a perspective view of a multilayer ceramic capacitor according to an embodiment of the present invention; [Diagram 2]2 is a cross-sectional view taken along line II-II' in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III' in FIG. [Figure 4] FIG. 3 is an enlarged partial cross-sectional view of part A in FIG. 2. [Diagram 5] FIG. 3 is an enlarged partial cross-sectional view of part B in FIG. 2. [Figure 6] 1 is a diagram showing a method for manufacturing a multilayer ceramic capacitor according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail so that a person having ordinary skill in the art to which the present invention belongs can easily carry out the present invention. In the drawings, parts that are not related to the description are omitted in order to clearly explain the present invention, and the same reference numerals are used for the same or similar components throughout the specification. In addition, in the accompanying drawings, some components are exaggerated, omitted, or shown in a schematic manner, and the size of each component does not completely reflect the actual size.

[0027] The accompanying drawings are intended to facilitate understanding of the embodiments disclosed in this specification, and are not intended to limit the technical ideas disclosed in this specification. It should be understood that the accompanying drawings include all modifications, equivalents, or alternatives included in the idea and technical scope of the present invention.

[0028] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0029] Furthermore, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, this includes not only when it is "directly on" the other part, but also when there is another part between them. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. Furthermore, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the opposite direction of gravity.

[0030] Throughout the specification, terms such as "comprise" or "have" are to be understood as specifying the presence of a feature, value, step, operation, component, part, or combination thereof described in the specification, but without precluding the possibility of the presence or addition of one or more other features, values, steps, operations, components, parts, or combinations thereof. Thus, when a part is described as "comprising" a certain element, this means that it can further include other elements, rather than excluding other elements, unless specifically stated to the contrary.

[0031] Additionally, throughout the specification, "on a plane" means when the target part is viewed from above, and "on a cross section" means when the target part is cut vertically and viewed from the side.

[0032] Furthermore, throughout the specification, the term "connected" does not only mean that two or more components are directly connected, but also that two or more components are indirectly connected through other components, that are not only physically connected but also electrically connected, or that are referred to by different names depending on their location or function but are nonetheless one unit.

[0033] FIG. 1 is a perspective view illustrating a multilayer ceramic capacitor according to an embodiment, FIG. 2 is a cross-sectional view taken along line II-II' in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III' in FIG.

[0034] 1 to 3, a multilayer ceramic capacitor 1000 according to the present embodiment includes a ceramic body 10, a plurality of internal electrodes 150, 160, protective layers 210, 310, a first external electrode 20, and a second external electrode 30. As shown in FIG.

[0035] First, to clearly explain this embodiment, the directions will be defined as follows: the L axis, W axis, and T axis shown in the drawing indicate the length direction, width direction, and thickness direction of the multilayer ceramic capacitor 1000, respectively.

[0036] The thickness direction (T-axis direction) may be a direction perpendicular to a broad surface (circumferential surface) of a sheet-shaped component. As an example, the thickness direction (T-axis direction) may be the same direction as the direction in which the dielectric layer 140 is laminated.

[0037] The length direction (L-axis direction) may be a direction parallel to the wide surface (principal surface) of the sheet-shaped component and may be a direction intersecting or perpendicular to the thickness direction (T-axis direction). As an example, the length direction (L-axis direction) may be a direction in which the first external electrode 20 and the second external electrode 30 face each other.

[0038] The width direction (W axis direction) is a direction parallel to the broad surface (circumferential surface) of a sheet-shaped component, and can be a direction that simultaneously intersects or is perpendicular to the thickness direction (T axis direction) and the length direction (L axis direction).

[0039] The ceramic body 10 may be configured to have an approximate hexahedral shape, but the present embodiment is not limited thereto. Due to shrinkage during sintering, the ceramic body 10 may have a substantially hexahedral shape, but not a perfect hexahedral shape. As an example, the ceramic body 10 may have an approximate rectangular hexahedral shape, but the corners and apexes may be rounded.

[0040] For ease of explanation, in this embodiment, the surfaces that face each other in the thickness direction (T-axis direction) are defined as first surface 11 and second surface 12, the surfaces that face each other in the length direction (L-axis direction) and connect first surface 11 and second surface 12 are defined as third surface 13 and fourth surface 14, and the surfaces that face each other in the width direction (W-axis direction) and intersect with the third and fourth surfaces 13, 14 are defined as fifth surface 15 and sixth surface 16.

[0041] Therefore, the first direction in which the first surface 11 and the second surface 12 face each other can be the height direction (T-axis direction), and the second and third directions which are perpendicular to the first direction and perpendicular to each other can be the length direction (L-axis direction) and width direction (W-axis direction), or the width direction (W-axis direction) and length direction (L-axis direction), respectively.

[0042] The length of the ceramic body 10 may refer to the maximum length of a plurality of line segments parallel to the length direction (L axis direction) of the ceramic body 10, which are obtained by connecting two outermost boundary lines facing each other in the length direction (L axis direction) of the ceramic body 10 shown in the cross-section photograph taken with an optical microscope or a scanning electron microscope (SEM) of a cross-section in the length direction (L axis direction)-thickness direction (T axis direction) at the center of the width direction (W axis direction) of the ceramic body 10. Meanwhile, the length of the ceramic body 10 may refer to the minimum length of a plurality of line segments parallel to the length direction (L axis direction) of the ceramic body 10 shown in the cross-section photograph taken with an optical microscope or a scanning electron microscope (SEM) of a cross-section in the length direction (L axis direction)-thickness direction (T axis direction) of the ceramic body 10 shown in the cross-section photograph taken with an optical microscope or a scanning electron microscope (SEM) of a cross-section ... On the other hand, the length of the ceramic body 10 may mean the arithmetic average value of the lengths of at least two of a plurality of line segments that connect two outermost boundary lines facing each other in the length direction (L-axis direction) of the ceramic body 10 shown in the cross-sectional photograph described above and are parallel to the length direction (L-axis direction).

[0043] The thickness of the ceramic body 10 may refer to the maximum value of the lengths of a plurality of line segments parallel to the thickness direction (T axis direction) by connecting two outermost boundary lines facing each other in the thickness direction (T axis direction) of the ceramic body 10 shown in the cross-section photograph taken with an optical microscope or a scanning electron microscope (SEM) of a cross-section in the length direction (L axis direction)-thickness direction (T axis direction) at the center of the width direction (W axis direction) of the ceramic body 10. Meanwhile, the thickness of the ceramic body 10 may refer to the minimum value of the lengths of a plurality of line segments parallel to the thickness direction (T axis direction) by connecting two outermost boundary lines facing each other in the thickness direction (T axis direction) of the ceramic body 10 shown in the cross-section photograph. Meanwhile, the thickness of the ceramic body 10 may refer to the arithmetic average value of the lengths of at least two line segments parallel to the thickness direction (T axis direction) by connecting two outermost boundary lines facing each other in the thickness direction (T axis direction) of the ceramic body 10 shown in the cross-section photograph.

[0044] The width of the ceramic body 10 may refer to the maximum value of the lengths of a plurality of line segments parallel to the width direction (W axis direction) by connecting two outermost boundary lines facing each other in the width direction (W axis direction) of the ceramic body 10 shown in the cross-section photograph taken with an optical microscope or a scanning electron microscope (SEM) of a cross-section in the length direction (L axis direction)-width direction (W axis direction) at the center of the thickness direction (T axis direction) of the ceramic body 10. Meanwhile, the width of the ceramic body 10 may refer to the minimum value of the lengths of a plurality of line segments parallel to the width direction (W axis direction) by connecting two outermost boundary lines facing each other in the width direction (W axis direction) of the ceramic body 10 shown in the cross-section photograph. Meanwhile, the width of the ceramic body 10 may refer to the arithmetic average value of the lengths of at least two line segments parallel to the width direction (W axis direction) by connecting two outermost boundary lines facing each other in the width direction (W axis direction) of the ceramic body 10 shown in the cross-section photograph.

[0045] The ceramic body 10 may be formed by stacking a plurality of dielectric layers 140 in a thickness direction (T-axis direction) and then firing the layers. Here, the plurality of adjacent dielectric layers 140 of the ceramic body 10 may be integrated with each other in a state where the boundaries between them are unclear. That is, the boundaries between the adjacent dielectric layers 140 of the ceramic body 10 may be integrated to such an extent that they are difficult to confirm without using a scanning electron microscope (SEM).

[0046] The internal electrodes 150, 160 include a first internal electrode 150 and a second internal electrode 160 having different polarities. The first and second internal electrodes 150, 160 may be alternately arranged in the thickness direction (T-axis direction) in the ceramic body 10 with the dielectric layer 140 therebetween. The first internal electrodes 150 and the second internal electrodes 160 adjacent to each other may be electrically insulated from each other by the dielectric layer 140 arranged therebetween.

[0047] The first and second internal electrodes 150, 160 may be arranged to be offset from each other in the length direction (L-axis direction) with the dielectric layer 140 therebetween. Ends of the first internal electrodes 150 may be exposed through the third surface 13 of the ceramic body 10, and ends of the second internal electrodes 160 may be exposed through the fourth surface 14 of the ceramic body 10. The ends of the first and second internal electrodes 150, 160 alternately exposed through the third and fourth surfaces 13, 14 of the ceramic body 10 may be connected to the first and second connection portions 21, 31 of the first and second external electrodes 20, 30, respectively, at the third and fourth surfaces 13, 14 of the ceramic body 10, and may be electrically connected thereto.

[0048] The first and second internal electrodes 150 and 160 may be formed by printing a conductive paste containing a conductive metal on the surface of the dielectric layer 140. For example, the internal electrodes may be formed by printing a conductive paste containing nickel (Ni) or a nickel (Ni) alloy on the surface of the dielectric layer by screen printing or gravure printing, but the present embodiment is not limited thereto.

[0049] As an example, the first and second internal electrodes 150, 160 may have an average thickness of approximately 0.1 μm or more and 2 μm or less.

[0050] With the above-described configuration, when a voltage is applied to the first and second external electrodes 20, 30, charge is accumulated between the opposing first and second internal electrodes 150, 160. The capacitance of the multilayer ceramic capacitor 1000 is proportional to the overlapping area of ​​the first and second internal electrodes 150, 160 that overlap each other along the thickness direction (T-axis direction).

[0051] The multilayer ceramic capacitor 1000 includes an active area and a margin area. The active area is an area where the first and second internal electrodes 150, 160 overlap in the thickness direction (T-axis direction), and the margin area is an area between the active area and the third and fourth faces 13, 14 of the ceramic body 10.

[0052] In the ceramic body 10, first and second cover layers 143, 145 may be disposed on both sides of the first and second internal electrodes 150, 160 along the thickness direction (T-axis direction). That is, the first cover layer 143 may be provided on the lower part of the lowermost internal electrode in the ceramic body 10, and the second cover layer 145 may be provided on the uppermost internal electrode. The first and second cover layers 143, 145 may have the same composition as the dielectric layer 140, and may be formed by laminating one or more dielectric layers not including an internal electrode on the lower part of the lowermost internal electrode and on the uppermost internal electrode of the ceramic body 10. The first and second cover layers 143, 145 may play a role in preventing damage to the first and second internal electrodes 150, 160 that may be caused by physical or chemical stress.

[0053] The dielectric layer 140 may include a ceramic material with a high dielectric constant. As an example, the ceramic material may include a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. These components may further include auxiliary components such as Mn compounds, Fe compounds, Cr compounds, Co compounds, and Ni compounds. As an example, the dielectric layer may include a ceramic material in which Ca (calcium), Zr (zirconium), etc. are partially dissolved in BaTiO3 (BaTiO3). 1-x Ca x )TiO3, Ba(Ti 1-y Ca y )O3, (Ba 1-x Ca x )(Ti 1-y Zr y )O3 or Ba(Ti 1-y Zr y )O3, but the present invention is not limited thereto.

[0054] The dielectric layer 140 may further include one or more of a ceramic additive, an organic solvent, a plasticizer, a binder, and a dispersant. The ceramic additive may include, for example, a transition metal oxide or carbide, a rare earth element, magnesium (Mg), or aluminum (Al).

[0055] As an example, the average thickness of the dielectric layer 140 may be 0.1 μm to 10 μm, but the present embodiment is not limited thereto.

[0056] The external electrodes 20, 30 are provided on the outside of the ceramic body 10 and include a first external electrode 20 and a second external electrode 30. The first and second external electrodes 20, 30 are disposed on third and fourth surfaces 13, 14 in the longitudinal direction (L-axis direction) of the ceramic body 10 and may extend to the first surface 11, the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10. In another embodiment, the first and second external electrodes 20, 30 may extend to a portion of either one of the first surface 11 and the second surface 12.

[0057] The first and second external electrodes 20, 30 include first and second connection portions 21, 31, first and second band portions 23, 33, and first and second corner portions 25, 35, respectively.

[0058] The first connecting portion 21 is a portion that covers the third surface 13 of the ceramic body 10 and is connected and electrically connected to exposed ends of the plurality of first or second internal electrodes 150, 160. The second connecting portion 31 is a portion that covers the fourth surface 14 of the ceramic body 10 and is connected and electrically connected to exposed ends of the plurality of first or second internal electrodes 150, 160. In another embodiment, the first connecting portion and the second connecting portion 21, 31 may cover a portion of the third surface 13 and the fourth surface 14.

[0059] The first and second band portions 23, 33 extend from the first and second connection portions 21, 31 and cover at least a portion of the first surface 11, the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10. The first and second band portions 23, 33 can further strongly adhere the first and second external electrodes 20, 30 to the ceramic body 10.

[0060] The first band portion 23 extends from the first connecting portion 21 and can cover at least a portion of the first surface 11, the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10. The second band portion 33 extends from the second connecting portion 31 and can cover at least a portion of the first surface 11, the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10.

[0061] The first and second corner portions 25, 35 may be portions that connect the first and second connection portions 21, 31 to the first and second band portions 23, 33.

[0062] Based on an optical microscope or scanning electron microscope (SEM) photograph of a cross-section in the length direction (L axis direction)-thickness direction (T axis direction) at the center of the width direction (W axis direction) of the multilayer ceramic capacitor 1000, in the multilayer ceramic capacitor 1000 shown in the cross-section photograph, the first and second connection parts 21, 31 may have a shape that is generally parallel to the thickness direction (T axis direction), the first and second band parts 23, 33 may have a shape that is generally parallel to the length direction (L axis direction), and the first and second corner parts 25, 35 may have a curved shape. The curved shape may be a curved shape having a tangent whose slope changes in a direction parallel to the thickness direction (T axis direction) in a direction parallel to the length direction (L axis direction) (or in the opposite direction).

[0063] The external electrodes 20, 30 may include a connection electrode 230, 330 and a plating electrode 250, 350. The connection electrode 230, 330 and the plating electrode 250, 350 may be located at least a portion of the first and second connection portions 21, 31, the first and second band portions 23, 33, and the first and second corner portions 25, 35, respectively. The first external electrode 20 may include a first connection electrode 230 and a first plating electrode 250, and the second external electrode 30 may include a second connection electrode 330 and a second plating electrode 350.

[0064] The connection electrodes 230 and 330 may include copper (Cu) or may include at least one of nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), or an alloy thereof, with copper (Cu) as the main component.

[0065] The connection electrodes 230, 330 may include protective particles 235, 335. The protective particles 235, 335 may include a glass component having a mixed oxide composition, and may include one or more selected from the group consisting of boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide together with silicon oxide. As an example, the protective particles 235, 335 may include one or more of barium oxide (BaO), calcium oxide (CaO), zinc oxide (ZnO), aluminum oxide (Al2O3), boron oxide (B2O3), sodium oxide (Na2O), and copper (II) oxide (CuO) together with silicon dioxide (SiO2), but are not limited thereto. In addition, the protective particles 235, 335 may include sodium oxide (Na2O) at 10 mol% or more and copper (II) oxide (CuO) at 4 mol% or more, but are not limited thereto. The protective particles 235, 335 may be particles of a glass material, or may be particles of the same material as the protective layers 210, 310 described below.

[0066] As an example, the connection electrodes 230, 330 can be formed by dipping the ceramic body 10 into a conductive paste containing a conductive metal and glass, by printing the conductive paste on the surface of the ceramic body 10 by screen printing or gravure printing, or by applying the conductive paste to the surface of the ceramic body 10.

[0067] The connection electrodes 230, 330 may include a first connection electrode 230 disposed on the third surface 13 of the ceramic body 10 and a second connection electrode 330 disposed on the fourth surface 14. The first connection electrode 230 may be disposed on the first connection portion 21 and extend to the first corner portion 25 and the first band portion 23. The second connection electrode 330 may be disposed on the second connection portion 31 and extend to the second corner portion 35 and the second band portion 33.

[0068] The plating electrodes 250, 350 may contain nickel (Ni) as a main component, and may further include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), etc., alone or in combination, but the present embodiment is not limited thereto. As an example, the plating electrodes 250, 350 may be formed by sputtering or electrolytic plating.

[0069] The plating electrodes 250, 350 may include a first plating electrode 250 at least partially covering the first connecting electrode 230 and a second plating electrode 350 at least partially covering the second connecting electrode 230. The first plating electrode 250 may be disposed in the first connecting portion 21 and extend to the first corner portion 25 and the first band portion 23. The second plating electrode 350 may be disposed in the second connecting portion 31 and extend to the second corner portion 35 and the second band portion 33.

[0070] 4 is an enlarged partial cross-sectional view of a portion A in FIG. 2, and FIG. 5 is an enlarged partial cross-sectional view of a portion B in FIG.

[0071] 4 and 5 , protective layers 210, 310 may be disposed on the third surface 13 and the fourth surface 14 of the ceramic body 10. The protective layers 210, 310 may be at least partially covered by the connecting electrodes 230, 330. The protective layers 210, 310 may include a first protective layer 210 disposed on the third surface 13 of the ceramic body 10 and a second protective layer 310 disposed on the fourth surface 14 of the ceramic body 10.

[0072] The first protective layer 210 may include a portion extending from the third surface 13 of the ceramic body 10 onto the first surface 11 and the second surface 12. The first protective layer 210 may also include a portion extending from the third surface 13 of the ceramic body 10 onto the fifth surface 15 and the sixth surface 16. The first protective layer 210 may be at least partially covered by the first connection electrode 230. The first protective layer 210 has a portion located between the ceramic body 10 and the first connection electrode 230 and may contact the ceramic body 10. The first protective layer 210 may play a role in adhering the ceramic body 10 and the first connection electrode 230.

[0073] The first protective layer 210 may have a first opening 217 formed on the third surface 13 of the ceramic body 10. The first opening 217 is a portion where the first protective layer 210 is not partially disposed. That is, the first protective layer 210 may be disposed on a portion of the third surface 13 of the ceramic body 10. The first opening 217 may overlap the first or second internal electrode 150, 160 exposed through the third surface 13 of the ceramic body 10, and the first connection electrode 230 may be in contact with the first or second internal electrode 150, 160 through the first opening 217.

[0074] The first protective layer 210 can include a first lower continuous region 211 , a first upper continuous region 213 , and a first intermittent region 215 .

[0075] The first lower continuous region 211 is a portion of the first protective layer 210 extending from the first surface 11 of the ceramic body 10 through the inside of the first corner portion 25 to a part of the third surface 13 of the ceramic body 10. One end of the first lower continuous region 211 may be located on the first surface 11 of the ceramic body 10, and the other end may be located on the third surface 13 of the ceramic body 10. One end of the first lower continuous region 211 located on the third surface 13 of the ceramic body 10 may be located on one side of the first opening 217, and this first opening 217 may be the first opening 217 located closest to the first surface 11 of the ceramic body 10. The first lower continuous region 211 may extend continuously without interruption from one end on the first surface 11 of the ceramic body 10 to one end on the third surface 13 of the ceramic body 10, and an opening may not be formed.

[0076] The first upper continuous region 213 is a portion of the first protective layer 210 extending from the second surface 12 of the ceramic body 10 through the inside of the first corner portion 25 to a part of the third surface 13 of the ceramic body 10. One end of the first upper continuous region 213 may be located on the second surface 12 of the ceramic body 10, and the other end may be located on the third surface 13 of the ceramic body 10. One end of the first upper continuous region 213 located on the third surface 13 of the ceramic body 10 is located on one side of the first opening 217, and this first opening 217 may be the first opening 217 located closest to the second surface 12 of the ceramic body 10. The first upper continuous region 213 may extend continuously from one end on the second surface 12 of the ceramic body 10 to one end on the third surface 13 of the ceramic body 10 without being interrupted, and an opening may not be formed.

[0077] The first interrupted region 215 is a region located between the first lower continuous region 211 and the first upper continuous region 213. That is, the first interrupted region 215 may be located between a first opening 217 located closest to the first surface 11 of the ceramic body 10 and a first opening 217 located closest to the second surface 12 of the ceramic body 10. The first opening 217 may be formed in the first interrupted region 215.

[0078] The first protective layer 210 may further protrude in a direction toward the fourth surface 14 of the ceramic body 10 from the first connection electrode 230 on the first surface 11, the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10. In addition, the first protective layer 210 may further protrude in a direction toward the fourth surface 14 of the ceramic body 10 from the first plating electrode 250 on the first surface 11, the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10.

[0079] The second protective layer 310 may include a portion extending from the fourth surface 14 of the ceramic body 10 onto the first surface 11 and the second surface 12. The second protective layer 310 may also include a portion extending from the fourth surface 14 of the ceramic body 10 onto the fifth surface 15 and the sixth surface 16. The second protective layer 310 may be at least partially covered by the second connection electrode 330. The second protective layer 310 may have a portion located between the ceramic body 10 and the second connection electrode 330 and may contact the ceramic body 10. The second protective layer 310 may play a role in adhering the ceramic body 10 and the second connection electrode 330.

[0080] The second protective layer 310 may have a second opening 317 formed on the fourth surface 14 of the ceramic body 10. The second opening 317 is a portion where the second protective layer 310 is not partially disposed. That is, the second protective layer 310 may be disposed on a portion of the fourth surface 14 of the ceramic body 10. The second opening 317 may overlap the first or second internal electrode 150, 160 exposed through the fourth surface 14 of the ceramic body 10, and the second connection electrode 330 may be in contact with the first or second internal electrode 150, 160 through the second opening 317.

[0081] The second protective layer 310 can include a second lower continuous region 311 , a second upper continuous region 313 , and a second interrupted region 315 .

[0082] The second lower continuous region 311 is a portion of the second protective layer 310 extending from the first surface 11 of the ceramic body 10 through the inside of the second corner portion 35 to a part of the fourth surface 14 of the ceramic body 10. One end of the second lower continuous region 311 may be located on the first surface 11 of the ceramic body 10, and the other end may be located on the fourth surface 14 of the ceramic body 10. One end of the second lower continuous region 311 located on the fourth surface 14 of the ceramic body 10 may be located on one side of the second opening 317, and this second opening 317 may be the second opening 317 located closest to the first surface 11 of the ceramic body 10. The second lower continuous region 311 may extend continuously without being interrupted from one end on the first surface 11 of the ceramic body 10 to one end on the fourth surface 14 of the ceramic body 10, and an opening may not be formed.

[0083] The second upper continuous region 313 is a portion of the second protective layer 310 extending from the second surface 12 of the ceramic body 10 through the inside of the second corner portion 35 to a part of the fourth surface 14 of the ceramic body 10. One end of the second upper continuous region 313 may be located on the second surface 12 of the ceramic body 10, and the other end may be located on the fourth surface 14 of the ceramic body 10. One end of the second upper continuous region 313 located on the fourth surface 14 of the ceramic body 10 may be located on one side of the second opening 317, and this second opening 317 may be the second opening 317 located closest to the second surface 12 of the ceramic body 10. The second upper continuous region 313 may extend continuously from one end on the second surface 12 of the ceramic body 10 to one end on the fourth surface 14 of the ceramic body 10 without being interrupted, and an opening may not be formed.

[0084] The second interrupted region 315 is a region located between the second lower continuous region 311 and the second upper continuous region 313. That is, the second interrupted region 315 may be located between the second opening 217 located closest to the first surface 11 of the ceramic body 10 and the second opening 217 located closest to the second surface 12 of the ceramic body 10. The second opening 317 may be formed in the second interrupted region 315.

[0085] The second protective layer 310 may further protrude in a direction toward the third surface 13 of the ceramic body 10 beyond the second connection electrode 330 on the first surface 11 and the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10. In addition, the second protective layer 310 may further protrude in a direction toward the third surface 13 of the ceramic body 10 beyond the second plating electrode 350 on the first surface 11 and the second surface 12, the fifth surface 15, and the sixth surface 16 of the ceramic body 10.

[0086] As an example, the average thickness of the protective layers 210, 310 may be approximately 0.1 μm to 10 μm, but the present embodiment is not limited thereto.

[0087] The protective layer 210, 310 may include a glass component having a mixed oxide composition, and may include one or more selected from the group consisting of boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide together with silicon oxide. As an example, the protective layer 210, 310 may include one or more of barium oxide (BaO), calcium oxide (CaO), zinc oxide (ZnO), aluminum oxide (Al2O3), boron oxide (B2O3), sodium oxide (Na2O), and copper (II) oxide (CuO) together with silicon dioxide (SiO2), but is not limited thereto. The protective layer 210, 310 may also include 5 mol% or more of sodium oxide (Na2O) together with silicon oxide, and 2 mol% or more of copper (II) oxide (CuO), but is not limited thereto. As an example, the protective layer 210, 310 may contain 7.5 mol% or more of sodium oxide (Na2O) together with silicon oxide, and as another example, the protective layer 210, 310 may contain 10 mol% or more of sodium oxide (Na2O) together with silicon oxide. As another example, the protective layer 210, 310 may contain 3 mol% or more of copper oxide (II) (CuO) together with silicon oxide, and as another example, the protective layer 210, 310 may contain 4 mol% or more of copper oxide (II) (CuO) together with silicon oxide. When sodium oxide (Na2O) and / or copper oxide (II) (CuO) is contained, the wettability of the protective layer 210, 310 is improved, and the protective layer 210, 310 is easily formed continuously between the ceramic body 10 and the connection electrode 230, 330.

[0088] Stress is more concentrated at the first and second corner portions 25, 35 than at the first and second connection portions 21, 31 and the first and second band portions 23, 33. Therefore, if cracks occur in the first and second corner portions 25, 35, the damaged or cracked portions may become paths for moisture to penetrate. The protective layers 210, 310 according to this embodiment increase the adhesive strength between the ceramic body 10 and the connection electrodes 230, 330, thereby reducing the risk of the external electrodes falling off, which is likely to occur at the first and second corner portions 25, 35.

[0089] For example, the ceramic body may be partially dipped into a conductive paste containing small glass particles to coat the conductive paste according to the degree of dilution of the solution, and then the conductive paste may be thermally dried at 200° C. and then fired to form the protective layers 210 and 310.

[0090] The multilayer ceramic capacitor 1000 is classified based on its length and width. Therefore, even if the multilayer ceramic capacitor has the same length and width, the size of the ceramic body may vary depending on the thickness of the external electrodes. That is, a multilayer ceramic capacitor having a thinner external electrode may have a larger ceramic body than a multilayer ceramic capacitor having a thicker external electrode. A larger ceramic body means a larger active area as described above, and may also mean a larger capacitance. Ultimately, the thinner the external electrodes of the multilayer ceramic capacitor, the larger the capacitance may be. However, if the thickness of the external electrodes is thin, moisture may easily penetrate into the ceramic body, which may reduce the moisture resistance reliability of the multilayer ceramic capacitor. In this embodiment, a protective layer is formed between the ceramic body and the connection electrodes, so that moisture penetration into the ceramic body can be suppressed even when the external electrodes are formed thin.

[0091] The protective layer 210, 310 may have low electrical conductivity. -7S / cm. The protective layers 210, 310 configured as above can prevent plating bleeding when the plating electrodes 250, 350 are formed. That is, if the first and second protective layers 210, 310 made of an insulating material protrude beyond the first and second connecting electrodes 230, 330, the plating components can be prevented from bleeding onto the protruding connecting electrodes 230, 330 during the formation of the plating electrodes 250, 350. Therefore, it is possible to prevent the plating electrodes 250, 350 from being formed beyond the protective layers 210, 310 in unintended regions of the ceramic body 10.

[0092] Hereinafter, a method for manufacturing a multilayer ceramic capacitor according to an embodiment will be described with reference to FIG.

[0093] FIG. 6 is a diagram showing a method for manufacturing a multilayer ceramic capacitor according to an embodiment.

[0094] 6, in the method for manufacturing a multilayer ceramic capacitor according to the present embodiment, first, a ceramic body is formed (S100). In order to form the ceramic body 10, first, a plurality of dielectric green sheets are prepared. The dielectric green sheets can become the dielectric layers 140 of the ceramic body 10 after firing.

[0095] The dielectric green sheet can be produced by mixing ceramic powder, ceramic additives, organic solvents, plasticizers, binders, dispersants, etc. to produce a paste, and then using a doctor blade or screen printing method to produce the paste into a sheet shape with a thickness of several μm.

[0096] As an example, the ceramic powder may include a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. In addition, these components may further include auxiliary components such as Mn compounds, Fe compounds, Cr compounds, Co compounds, and Ni compounds. For example, BaTiO3-based dielectric ceramics in which Ca, Zr, etc. are partially dissolved (Ba 1-x Ca x )TiO3, Ba(Ti1-y Ca y )O3, (Ba 1-x Ca x )(Ti 1-y Zr y )O3 or Ba(Ti 1-y Zr y )O3, etc.

[0097] Ceramic additives may include, for example, transition metal oxides or carbides, rare earth elements, magnesium (Mg) or aluminum (Al).

[0098] A conductive paste layer is formed on the surface of the dielectric green sheet, which can become the first and second internal electrodes 150, 160 after firing.

[0099] The conductive paste layer can be formed by applying a conductive paste containing a conductive metal onto the surface of the dielectric green sheet using a method such as a doctor blade or screen printing method.

[0100] As an example, a first conductive paste layer can be applied to a surface of a first dielectric green sheet in a first pattern, and a second conductive paste layer can be applied to a surface of a second dielectric green sheet in a second pattern. The first and second patterns can be aligned such that the first and second conductive paste layers partially overlap and partially do not overlap when the first and second dielectric green sheets are alternately laminated.

[0101] The first and second dielectric green sheets are laminated to produce a dielectric green sheet laminate. The first and second dielectric green sheets are laminated such that the first and second conductive paste layers overlap and at least partially do not overlap. Optionally, the dielectric green sheet laminate is pressure-bonded.

[0102] The dielectric green sheet laminate can be cut so that the first and second conductive paste layers are exposed through both side end surfaces. The ends of the first and second internal electrodes 150 and 160 can be exposed on either of both end surfaces of the dielectric green sheet laminate.

[0103] The dielectric green sheet laminate is fired at a high temperature to manufacture the ceramic body 10. After firing, the dielectric green sheets form the dielectric layers 140. The conductive paste layers formed on the surfaces of the dielectric green sheets form first and second internal electrodes 150, 160 by firing, and one dielectric layer 140 can be alternately arranged between them. The first and second internal electrodes 150, 160 can be electrically insulated by the dielectric layers 140.

[0104] A liquid conductive paste layer is formed on both side cross sections of the ceramic body 10 where the first and second internal electrodes 150, 160 are exposed (S200). The liquid conductive paste layer may be formed by dipping the ceramic body 10 into a conductive paste containing a conductive metal and glass powder. As another example, the liquid conductive paste layer may be formed by printing the conductive paste on the surface of the ceramic body 10 using a screen printing method, a gravure printing method, or the like, or by coating the conductive paste on the surface of the ceramic body 10.

[0105] Next, the liquid conductive paste layer is dried (S300). The liquid conductive paste layer may be dried at 200° C. After drying, the shape of the external electrode is formed, and the external electrode may be temporarily fixed to the ceramic body 10.

[0106] Subsequently, the conductive paste layer is fired (S400) to form a fixed external electrode and connect the internal electrode and the external electrode. Firing the conductive paste layer can include debinding (S410), connecting the internal electrode and the external electrode (S420), and forming a protective layer (S430).

[0107] Debinding may be performed on the conductive paste layer (S410). Debinding includes removing organic matter, such as binders, from the conductive paste layer. Debinding may be performed at 600° C. Debinding may result in voids being formed within the conductive paste layer.

[0108] Next, the internal electrodes and the external electrodes can be connected (S420). In this step, adjacent metal powders are necked in an environment of 500°C to 800°C, and the molten metal can grow. At this time, the molten metal flows and fills the voids formed by the debinding described above. In addition, the molten metal flows at the interface of the ceramic body 10, and a portion where the connection electrode of the external electrode and the internal electrode are connected can be formed.

[0109] Next, a protective layer can be formed (S430). In this step, the adjacent glass powders can be necked in an environment of 550°C to 800°C to grow molten glass. At this time, the molten glass can flow and fill the voids inside the external electrodes, forming a glass film on the surface of the ceramic body 10. The formed glass film can become the protective layers 210 and 310. The glass powders can be continuously connected to each other to cover the surface of the ceramic body 10, and openings 217 and 317 can be formed at the portions where the connection electrodes of the external electrodes and the internal electrodes are connected. The openings 217 and 317 are portions where the glass film is not formed, and the internal electrodes 150 and 160 can be connected to the connection electrodes 230 and 330 through the openings 217 and 317. The molten metal and molten glass can fill the voids formed as a result of debinding, making the external electrodes more dense.

[0110] Hereinafter, experimental examples comparing the examples of the present invention with comparative examples will be presented. However, the examples and experimental examples described below are merely intended to specifically illustrate or explain the present invention, and are not intended to limit the scope of the present invention.

[0111] [Comparative Examples, Examples and Evaluation Methods] (Example) Several sintered 1005 size ceramic bodies were prepared, and liquid conductive paste layers containing conductive metal and glass powder were formed on both ends of the laminate where the internal electrodes were exposed. The conductive paste layers were dried and sintered to form external electrodes with glass films and connection electrodes. Then, plated electrodes were formed on the sintered external electrodes.

[0112] (Comparative Example) Several sintered 1005 size ceramic bodies were prepared, and liquid conductive paste layers containing conductive metal were formed on both ends of the laminate where the internal electrodes were exposed. The conductive paste layers were dried and sintered to form external electrodes. Then, plated electrodes were formed on the sintered external electrodes.

[0113] (Judgment method) The presence or absence of glass film formation can be determined by checking the contrast of light and dark in an image of the multilayer ceramic capacitor measured with a Scanning Electron Microscope (SEM), or by examining whether glass components, such as Si components, are detected using an Energy Dispersive X-ray Spectroscopy (EDX) or an Electron Probe Micro-Analyzer (EPMA).

[0114] [Experimental example: performance of multilayer ceramic capacitor] The multilayer ceramic capacitors manufactured in the examples and comparative examples were measured for external electrode blister defects, plating bleeding defects, and moisture resistance deterioration.

[0115] 1) External electrode dropout measurement 100 pieces of each of the multilayer ceramic capacitors of the Example and Comparative Example were prepared. In order to confirm the effect of the multilayer ceramic capacitor of this Example, the external electrodes of the Comparative Example and Example were fired in a strong reducing atmosphere. Then, plating electrodes were formed on the fired external electrodes.

[0116] [Table 1]

[0117] As shown in Table 1, in the comparative example, 15 out of 100 samples had defects in which the external electrodes fell off, while no such defects occurred in the samples of the embodiment. This is because the glass film acts as an adhesive between the ceramic body and the connection electrodes, making the connection electrodes more firmly fixed.

[0118] 2) Plating bleeding failure 100 pieces of each of the multilayer ceramic capacitors of the example and the comparative example were prepared. In the example, the external electrodes were formed so that the glass film protruded toward the center of the ceramic body from the connection electrodes. Then, plated electrodes were formed on the fired external electrodes.

[0119] [Table 2]

[0120] As shown in Table 2, in the comparative example, 14 out of 100 samples showed plating bleeding defects on the surface of the ceramic body where no external electrodes were formed. In the examples, no plating bleeding defects occurred. This is because the glass film prevents the plating electrode from diffusing beyond the glass film.

[0121] 3) Humidity deterioration measurement 20 channels of each of the multilayer ceramic capacitors of the examples and the comparative examples were prepared. Each channel was composed of 20 multilayer ceramic capacitors connected in series. A voltage of 1.5 Vr was applied to each of the 20 channels of the examples and the comparative examples prepared in this way for 12 hours in an environment of 85°C and 85% RH.

[0122] [Table 3]

[0123] As shown in Table 3, moisture degradation occurred in 3 out of 20 channel samples, while moisture degradation did not occur in the example sample. This is because the glass film formed on the surface of the ceramic body suppressed moisture penetration into the ceramic body.

[0124] Although the preferred embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the description of the invention, and the accompanying drawings, and it is natural that these also fall within the scope of the present invention. [Explanation of symbols]

[0125] 1000 Multilayer Ceramic Capacitor 10 Ceramic body 140 Dielectric layer 150 1st internal electrode 160 2nd internal electrode 20 1st external electrode 210 1st protective layer 230 First connection electrode 250 First plating electrode 30 2nd external electrode 310 Second protective layer 330 Second connection electrode 350 Second plating electrode

Claims

1. a ceramic body including a first surface and a second surface facing a first direction, a third surface and a fourth surface facing a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface facing a third direction and connecting the first surface and the second surface; an internal electrode disposed within the ceramic body; a protective layer disposed on the third surface and the fourth surface of the ceramic body; a connection electrode covering the protective layer; the protective layer includes a first protective layer disposed on the third surface and a second protective layer disposed on the fourth surface, and the multilayer ceramic capacitor has openings located on the third surface and the fourth surface.

2. The multilayer ceramic capacitor according to claim 1 , wherein the first protective layer and the second protective layer each include a portion extending to the first surface and the second surface.

3. The multilayer ceramic capacitor according to claim 1 , wherein the internal electrodes are connected to the connection electrodes through the openings.

4. The multilayer ceramic capacitor of claim 1 , wherein the protective layer comprises silicon (Si) oxide.

5. The protective layer has an electrical conductivity of 10 －７ The multilayer ceramic capacitor of claim 1 , wherein the capacitance is less than 1.0 S / cm.

6. The protective layer is made of sodium oxide (Na ２ The multilayer ceramic capacitor according to claim 4 , further comprising:

7. The multilayer ceramic capacitor according to claim 4 , wherein the protective layer comprises copper (II) oxide (CuO).

8. The multilayer ceramic capacitor according to claim 4 , wherein the connection electrodes contain particles of the same material as the protective layer.

9. the connection electrode includes a first connection electrode at least partially covering the first protective layer and a second connection electrode at least partially covering the second protective layer; the first protective layer has a portion on the first surface and the second surface of the ceramic body that protrudes beyond the first connection electrode in the fourth surface direction, 3 . The multilayer ceramic capacitor according to claim 2 , wherein the second protective layer has a portion on the first surface and the second surface of the ceramic body that protrudes beyond the second connection electrode in the third surface direction.

10. a first plating electrode at least partially covering the first connection electrode and a second plating electrode at least partially covering the second connection electrode; the first protective layer has portions on the first surface and the second surface of the ceramic body that protrude beyond the first plating electrode in the fourth surface direction; 10. The multilayer ceramic capacitor according to claim 9, wherein the second protective layer has portions on the first surface and the second surface of the ceramic body that protrude beyond the second plating electrode in the third surface direction.

11. The multilayer ceramic capacitor according to claim 1 , wherein the first protective layer and the second protective layer have portions in contact with the ceramic body.

12. a ceramic body including a first surface and a second surface facing a first direction, a third surface and a fourth surface facing a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface facing a third direction and connecting the first surface and the second surface; an internal electrode disposed within the ceramic body; a protective layer disposed on a portion of the third surface and a portion of the fourth surface of the ceramic body; a connection electrode covering the protective layer; the connection electrodes include portions that contact the internal electrodes through portions on the third surface and the fourth surface of the ceramic body where the protective layer is not located.

13. The multilayer ceramic capacitor of claim 12 , wherein the protective layer includes a portion that extends onto the first surface and the second surface.

14. an opening is formed on the third surface and the fourth surface of the ceramic body at a portion where the protective layer is located; The multilayer ceramic capacitor according to claim 13 , wherein the protective layer has a portion that extends continuously from an end on the first surface or the second surface to another end located on one side of the opening.

15. the protective layer includes a first protective layer extending along the first surface, the third surface, and the second surface, and a second protective layer extending along the first surface, the fourth surface, and the second surface; the connection electrode includes a first connection electrode covering the first protective layer and a second connection electrode covering the second protective layer; the first protective layer has a portion on the first surface and the second surface that protrudes further in a direction toward the fourth surface than the first connection electrode, The multilayer ceramic capacitor according to claim 13 , wherein the second protective layer has a portion on the first surface and the second surface that protrudes further in the direction of the third surface than the second connection electrode.

16. a first plating electrode covering the first connection electrode and a second plating electrode covering the second connection electrode, the first protective layer has a portion on the first surface and the second surface that protrudes further in a direction toward the fourth surface than the first plating electrode, The multilayer ceramic capacitor according to claim 15 , wherein the second protective layer has a portion on the first surface and the second surface that protrudes further toward the third surface than the second plating electrode.

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