Multilayer ceramic capacitor

Abstract

To provide a multilayer ceramic capacitor capable of improving moisture resistance reliability by blocking a moisture permeation path.SOLUTION: Disclosed is a multilayer ceramic capacitor which comprises a dielectric layer, a first internal electrode and a second internal electrode which face each other with the dielectric layer therebetween, and a first cover layer arranged on at least one of the first internal electrode and the second internal electrode, wherein the first cover layer is divided into a center region and a side region located outside the center region, and the side region has a surface inclined downward at an angle of not less than 18 ° but not more than 20 ° with respect to the surface of the center region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Multi-layered ceramic capacitors (MLCCs), a type of multilayer electronic component, are chip-type capacitors that are mounted on the printed circuit boards of various electronic products such as video equipment (OLED, LED), computers, smartphones, and mobile phones to store and release electrical charges when needed.

[0003] Such multilayer ceramic capacitors can be used as components of various electronic devices due to their advantages of being small, yet having high capacitance, and being easy to mount. As various electronic devices such as computers and mobile devices become smaller and have higher output, there is a growing demand for multilayer ceramic capacitors with higher capacitance and smaller size.

[0004] As multilayer ceramic capacitors become smaller, moisture easily penetrates from the outside to the internal electrodes, increasing the likelihood of defects in the multilayer ceramic capacitor. In particular, moisture penetration paths are likely to occur from the corners of the ceramic body to the ends of the internal electrodes, and measures to block such moisture penetration paths are necessary. Summary of the Invention [Problem to be solved by the invention]

[0005] One aspect of the embodiment provides a multilayer ceramic capacitor capable of improving moisture resistance reliability by blocking a moisture penetration path. [Means for solving the problem]

[0006] According to one embodiment, the multilayer ceramic capacitor includes a dielectric layer, first and second internal electrodes facing each other across the dielectric layer, and a first cover layer disposed on at least one of the first and second internal electrodes, the first cover layer being divided into a center region and a side region located outside the center region, and the side region has a surface that slopes downward at an angle of 18° to 20° from the surface of the center region.

[0007] The side regions are disposed so as to surround the center region.

[0008] The center region may be located above an active region where the first internal electrode and the second internal electrode overlap.

[0009] The side region may also be located on a margin region surrounding the active region.

[0010] Also, the center region may not overlap the margin region, and the side region may not overlap the active region.

[0011] The inclination may be an angle at which the surface of the side region is inclined with respect to an extension line of an uppermost internal electrode located at the top of the first internal electrode and the second internal electrode.

[0012] The dielectric layer, the first internal electrode, and a second cover layer located below the second internal electrode may be included, and a portion of the second cover layer overlapping with the side region may have the inclination based on a line parallel to the side region. [Effects of the Invention]

[0013] According to at least one of the multilayer ceramic capacitors according to the embodiments, at least a portion of the corners of the ceramic body may be inclined at a predetermined angle, thereby blocking a moisture penetration path and improving moisture resistance reliability. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment of the present invention; [Figure 2] 2 is a perspective view showing the multilayer ceramic capacitor of FIG. 1 with a ceramic body separated therefrom. [Figure 3] 3 is a perspective view showing the ceramic body of FIG. 2 with a first cover layer separated therefrom. [Figure 4] FIG. 2 is a cross-sectional view taken along line III-III' in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing the ceramic body in FIG. 4 in a separated state. [Figure 6] FIG. 2 is a schematic diagram showing a portion of a ceramic body in isolation. [Figure 7] 7 is an enlarged view of part VII of FIG. 5. [Figure 8] 8 is an enlarged view of part VIII of FIG. 5. [Figure 9] 1 is a diagram showing a plurality of dielectric green sheets. [Figure 10] 10 is a diagram showing a laminated structure of a ceramic body using the dielectric green sheet of FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. In the drawings, parts unnecessary for the explanation of the present invention are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components. In addition, in the accompanying drawings, some components are exaggerated, omitted, or illustrated schematically, and the size of each component does not completely reflect the actual size.

[0016] The attached drawings are provided to facilitate understanding of the embodiments disclosed in this specification, and it should be understood that the attached drawings do not limit the technical ideas disclosed in this specification, and include all modifications, equivalents, and alternatives included within the idea and technical scope of the present invention.

[0017] 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.

[0018] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes the case where it is "directly above" that other part, as well as the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. 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 direction opposite to gravity.

[0019] Throughout the specification, the use of terms such as "comprises" or "having" is intended to specify the presence of a stated feature, numeral, step, operation, component, part, or combination thereof, but should be understood as not precluding the presence or addition of one or more other features, numerals, steps, operations, components, parts, or combinations thereof. Thus, when a part is said to "comprise" a certain component, this means that it can further include other components, but not to the exclusion of other components, unless otherwise specified.

[0020] Throughout the specification, "in a plane" means a portion of the subject viewed from above, and "in cross section" means a portion of the subject viewed from the side through a vertical cross section.

[0021] Throughout the specification, when the term "connected" is used, it does not only mean that two or more components are directly connected, but also that two or more components are indirectly connected by other components, or that two or more components are not only physically connected but are electrically connected, or that two or more components are referred to by different names depending on their position or function but are nonetheless one unit.

[0022] In this specification, when describing a multilayer ceramic capacitor, the direction in which the main components of the multilayer ceramic capacitor are stacked is defined as the "stacking direction," but this may also be the "thickness direction." Also, the direction parallel to a plane perpendicular to the stacking direction can be defined as the "planar direction."

[0023] FIG. 1 is a perspective view schematically illustrating a multilayer ceramic capacitor 10 according to an embodiment, FIG. 2 is a perspective view illustrating the multilayer ceramic capacitor 10 of FIG. 1 with the ceramic body 100 separated therefrom, FIG. 3 is a perspective view illustrating the ceramic body 100 of FIG. 2 with the first cover layer 140 separated therefrom, and FIG. 4 is a cross-sectional view taken along line III-III' of FIG. 1.

[0024] 1, 2, 3 and 4, the multilayer ceramic capacitor according to this embodiment includes a ceramic body 100, a first external electrode 200 and a second external electrode 300. As shown in FIG.

[0025] First, to clearly explain this embodiment, the directions will be defined. The L axis, W axis, and T axis shown in the drawings indicate the length direction, width direction, and thickness direction of the ceramic body 100, respectively.

[0026] The thickness direction (T-axis direction) may be a direction perpendicular to the broad surface (main surface) of a sheet-shaped component. For example, the thickness direction (T-axis direction) can be used in the same concept as the direction in which the components of the ceramic body 100 are stacked.

[0027] The length direction (L-axis direction) may be a direction aligned with the broad surface (principal surface) of the sheet-shaped component and intersecting (or perpendicular to) the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be a direction in which the first external electrode 200 and the second external electrode 300 face each other.

[0028] The width direction (W axis direction) may be a direction aligned with the wide surface (main surface) of a sheet-shaped component and may simultaneously intersect (or be perpendicular to) the thickness direction (T axis direction) and the length direction (L axis direction).

[0029] The ceramic body 100 has a substantially hexahedral shape, but this embodiment is not limited thereto. Due to shrinkage during sintering, the ceramic body 100 may have a substantially hexahedral shape, but not a perfect hexahedral shape. For example, the ceramic body 100 may have a substantially rectangular hexahedral shape, but the corners and vertices may be rounded, and the outer portion of the upper part may be slanted downward.

[0030] In this embodiment, for ease of explanation, the surfaces facing each other in the length direction (L axis direction) are defined as the first surface (S1) and the second surface (S2), the 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 third surface (S3) and the fourth surface (S4), and the 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 fifth surface (S5) and the sixth surface (S6).

[0031] In this embodiment, the fifth and sixth surfaces are defined as the upper and lower surfaces, respectively. In this case, the lower surface may be the surface that is mounted on the board.

[0032] Therefore, the first 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 that 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), respectively. In another example, the first 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 that are perpendicular to the first direction and perpendicular to each other may be the width direction (W-axis direction) and the thickness direction (T-axis direction), respectively.

[0033] The length of the ceramic body 100 may refer to the maximum length of a plurality of sections parallel to the length direction (L axis direction) of the ceramic body 100 while connecting two outermost boundary lines facing each other in the length direction (L axis direction) of the ceramic body 100 in the cross-section taken through an optical microscope or a scanning electron microscope (SEM) at the center of the width direction (W axis direction) of the ceramic body 100. The length of the ceramic body 100 may refer to the minimum length of a plurality of sections parallel to the length direction (L axis direction) of the ceramic body 100 while connecting two outermost boundary lines facing each other in the length direction (L axis direction) of the ceramic body 100 in the cross-section. The length of the ceramic body 100 may refer to the arithmetic average length of at least two of a plurality of sections parallel to the length direction (L axis direction) of the ceramic body 100 while connecting two outermost boundary lines facing each other in the length direction (L axis direction) of the ceramic body 100 in the cross-section.

[0034] The thickness of the ceramic body 100 may refer to the maximum length of a plurality of segments parallel to the thickness direction (T axis direction) of the ceramic body 100, connecting two outermost boundary lines facing each other in the thickness direction (T axis direction) of the ceramic body 100, based on an optical microscope or scanning electron microscope (SEM) photograph of a length direction (L axis direction)-thickness direction (T axis direction) cross-section at the center of the width direction (W axis direction) of the ceramic body 100. The thickness of the ceramic body 100 may refer to the minimum length of a plurality of segments parallel to the thickness direction (T axis direction) of the ceramic body 100, connecting two outermost boundary lines facing each other in the thickness direction (T axis direction) of the ceramic body 100, based on the optical microscope or scanning electron microscope (SEM) photograph of the ceramic body 100. The thickness of the ceramic body 100 may refer to the arithmetic average length of at least two segments parallel to the thickness direction (T axis direction) of the ceramic body 100, connecting two outermost boundary lines facing each other in the thickness direction (T axis direction) of the ceramic body 100, based on the cross-section.

[0035] The width of the ceramic body 100 may refer to the maximum length of a plurality of segments parallel to the width direction (W axis direction) of the ceramic body 100, connecting two outermost boundary lines facing each other in the width direction (W axis direction) of the ceramic body 100, based on an optical microscope or scanning electron microscope (SEM) photograph of a length direction (L axis direction)-width direction (W axis direction) cross-section at the center of the thickness direction (T axis direction) of the ceramic body 100. The width of the ceramic body 100 may refer to the minimum length of a plurality of segments parallel to the width direction (W axis direction) of the ceramic body 100, connecting two outermost boundary lines facing each other in the width direction (W axis direction) of the ceramic body 100, based on the optical microscope or scanning electron microscope (SEM) photograph of the length direction (L axis direction)-width direction (W axis direction) cross-section at the center of the thickness direction (T axis direction) of the ceramic body 100. The width of the ceramic body 100 may refer to the arithmetic average length of at least two segments parallel to the width direction (W axis direction) of the ceramic body 100, connecting two outermost boundary lines facing each other in the width direction (W axis direction) of the ceramic body 100, based on the optical microscope or scanning electron microscope (SEM) photograph of the length direction (L axis direction)-width direction (W axis direction) of the ceramic body 100.

[0036] Meanwhile, the length, width, and thickness of the ceramic body 100 may each be measured using a micrometer measurement method. The micrometer measurement method can be performed by setting the zero point with a gauge R&R (Repeatability and Reproducibility) micrometer, inserting the ceramic body 100 according to this embodiment between the tips of the micrometer, and turning the measuring lever of the micrometer. Meanwhile, when measuring the length of the ceramic body 100 using the micrometer measurement method, the length of the ceramic body 100 may refer to a value measured once or the arithmetic average value of values ​​measured multiple times. This can also be applied to measuring the width and thickness of the ceramic body 100.

[0037] The ceramic body 100 includes a dielectric layer 110 , a first internal electrode 120 , a second internal electrode 130 , a first cover layer 140 , and a second cover layer 150 .

[0038] The dielectric layers 110 can be stacked in the thickness direction (T-axis direction) of the ceramic body 100. The boundaries between the dielectric layers 110 may be unclear. That is, the multiple dielectric layers 110 may appear as a single integrated structure. For example, the boundaries between the dielectric layers 110 may be so unclear that they are difficult to identify without using a scanning electron microscope (SEM).

[0039] The dielectric layer 110 may include a ceramic material with a high dielectric constant. For 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 manganese (Mn) compounds, iron (Fe) compounds, chromium (Cr) compounds, cobalt (Co) compounds, and nickel (Ni) compounds. For example, the dielectric layer 110 may include a ceramic material in which calcium (Ca), zirconium (Zr), etc. are partially dissolved in BaTiO3 (Ba 1-x Cax )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.

[0040] The dielectric layer 110 may further include one or more of a ceramic additive, an organic solvent, a plasticizer, a binder, and a dispersant. For example, the ceramic additive may include a transition metal oxide, a carbide, a rare earth element, magnesium (Mg), or aluminum (Al).

[0041] The slurry for forming the dielectric layer 110 may also contain a binder. The binder is used to impart plasticity and shape retention. The binder decomposes during the firing process, and may not remain in the dielectric layer 110 after firing.

[0042] The first internal electrodes 120 and the second internal electrodes 130 may be alternately stacked with the dielectric layers 110 sandwiched between them. That is, a first internal electrode 120 / dielectric layer 110 / second internal electrode 130 / dielectric layer 110 structure is repeatedly arranged inside the ceramic body 100. As an example, the internal electrode closest to the fifth surface (S5) of the ceramic body 100 may be the first internal electrode 120, and the internal electrode closest to the sixth surface (S6) may be the second internal electrode 130. As another example, the internal electrode closest to the fifth surface (S5) of the ceramic body 100 may be the second internal electrode 130, and the internal electrode closest to the sixth surface (S6) may be the first internal electrode 120.

[0043] The first internal electrode 120 and the second internal electrode 130 have different polarities and can be electrically insulated from each other by the dielectric layer 110 located therebetween.

[0044] The first internal electrode 120 and the second internal electrode 130 are arranged to be offset from each other in the length direction (L-axis direction) with the dielectric layer 110 sandwiched therebetween. That is, the first internal electrode 120 and the second internal electrode 130 are arranged to partially overlap each other in the thickness direction (T-axis direction) and not to partially overlap each other. One side end of the first internal electrode 120 may be exposed through the first surface (S1) of the ceramic body 100. One side end of the second internal electrode 130 may be exposed through the second surface (S2) of the ceramic body 100. The end of the first internal electrode 120 exposed from the first surface (S1) of the ceramic body 100 may be connected to the first external electrode 200. The end of the second internal electrode 130 exposed from the second surface (S2) of the ceramic body 100 may be connected to the second external electrode 300.

[0045] The first internal electrode 120 and the second internal electrode may be formed by printing a conductive paste on the surface of the dielectric layer 110. In this case, the conductive paste may contain a conductive metal. 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 green sheet 500 by screen printing or gravure printing. However, this embodiment is not limited thereto.

[0046] For example, the average thickness of the first internal electrode 120 and the second internal electrode 130 may be approximately 0.1 μm or more and 2 μm or less.

[0047] Here, the thickness of the internal electrode may refer to the average thickness of one internal electrode disposed between two dielectric layers 110. The average thickness of the internal electrode may be an arithmetic average value of thicknesses of one internal electrode appearing in a scanning electron microscope (SEM) photograph of a cross section in the length direction (L axis direction) and thickness direction (T axis direction) at the center of the width direction (W axis direction) of the ceramic body 100, measured at 30 evenly spaced locations in the length direction (L axis direction).

[0048] When a voltage is applied to the first external electrode 200 and the second external electrode 300, a charge is accumulated between the first internal electrode 120 and the second internal electrode 130, which are adjacent to each other. That is, a capacitance can be obtained between the first internal electrode 120 electrically connected to the first external electrode 200 and the second internal electrode 130 electrically connected to the second external electrode 300. The capacitance of the multilayer ceramic capacitor 10 is proportional to the overlapping area of ​​the first internal electrode 120 and the second internal electrode 130 that overlap each other along the thickness direction (T-axis direction).

[0049] Fig. 5 is a cross-sectional view showing the ceramic body 100 in isolation from Fig. 4. Fig. 6 is a schematic view showing a portion of the ceramic body in isolation.

[0050] 5 and 6, the ceramic body 100 can be divided into an active region (A) and a margin region (M) based on the region where electric charges are substantially formed.

[0051] The active area (A) is a portion of the ceramic body where charge is accumulated. The active area (A) may be a region where the first internal electrode 120 and the second internal electrode 130 overlap each other in the thickness direction (T-axis direction) of the ceramic body 100. The margin area (M) may be a region where the first internal electrode 120 and the second internal electrode 130 do not overlap each other. In other words, the margin area (M) may be a region between the active area (A) and an end surface of the ceramic body 100. The margin area (M) includes a first margin area (M1) between the active area (A) and the first surface (S1), a second margin area (M2) between the active area (A) and the second surface (S2), a third margin area (M3) between the active area (A) and the third surface (S3), and a fourth margin area (M4) between the active area (A) and the fourth surface (S4).

[0052] In the active area (A), a plurality of first internal electrodes 120 and second internal electrodes 130 overlap, while in the first margin area (M1), a plurality of first internal electrodes 120 are located, and in the second margin area (M2), a plurality of second internal electrodes 130 are located. In addition, in the third margin area (M3) and the fourth margin area (M4), neither the first internal electrodes 120 nor the second internal electrodes 130 are arranged.

[0053] The dielectric is made of a ceramic material, while the first internal electrode 120 and the second internal electrode 130 are made of a metal material, so there is a difference in the shrinkage rate when pressure is applied, which can cause a slope to form at the edge portion of the first cover layer 140 during sintering.

[0054] 5, a first cover layer 140 and a second cover layer 150 are disposed above and below the active region (A) and the margin region (M) in the thickness direction (T-axis direction), respectively. The first cover layer 140 is disposed between the fifth surface (S5) of the ceramic body 100 and the internal electrode closest thereto. The second cover layer 150 is disposed between the sixth surface (S6) of the ceramic body 100 and the internal electrode closest thereto.

[0055] That is, the first cover layer 140 is disposed over the internal electrode (hereinafter referred to as the "uppermost internal electrode") located at the top of the internal electrodes in the thickness direction (T-axis direction). The second cover layer 150 is disposed under the internal electrode (hereinafter referred to as the "lowermost internal electrode") located at the bottom of the internal electrodes in the thickness direction (T-axis direction). The first cover layer 140 and the second cover layer 150 may have the same composition as the dielectric layer 110. The first cover layer 140 may be formed by stacking one or more other dielectric layers on the topmost internal electrode and the dielectric layer parallel to the topmost internal electrode. The second cover layer 150 may be formed by stacking one or more other dielectric layers below the bottommost internal electrode and the dielectric layer parallel to the bottommost internal electrode.

[0056] The first cover layer 140 and the second cover layer 150 may serve to prevent damage to the first internal electrode 120 and the second internal electrode 130 due to physical or chemical stress.

[0057] Referring to FIG. 3, the first cover layer 140 can be divided into a center region 141 and a side region 143 .

[0058] The center region 141 is located in the middle of the first cover layer 140. The center region 141 can be defined as a portion that overlaps with the active region (A) in the thickness direction (T-axis direction). The surface of the center region 141 can be approximately parallel to the first internal electrode 120 or the second internal electrode 130. That is, the portion of the center region 141 exposed to the fifth surface can be approximately parallel to the first internal electrode 120 or the second internal electrode 130.

[0059] The side region 143 is located outside the center region 141. The side region 143 is an edge portion of the first cover layer 140 and is disposed to surround the center region 141. The side region 143 can be defined as a portion overlapping the margin region (M) in the thickness direction (T-axis direction). That is, referring to FIG. 3, the side region 143 includes a first side region 1431 between the center region 141 and the first surface (S1), a second side region 1432 between the center region 141 and the second surface (S2), a third side region 1433 between the center region 141 and the third surface (S3), and a fourth side region 1434 between the center region 141 and the fourth surface (S4). The first side region 1431, the second side region 1432, the third side region 1433, and the fourth side region 1434 overlap with the first margin region (M1), the second margin region (M2), the third margin region (M3), and the fourth margin region (M4), respectively, in the thickness direction (T-axis direction).

[0060] In other words, in the thickness direction (T-axis direction), the center region 141 can be located above the active region (A). The center region 141 may not overlap with the margin region (M). Also, in the thickness direction (T-axis direction), the side region 143 can be located above the margin region (M). The side region 143 may not overlap with the active region (A).

[0061] Fig. 7 is an enlarged view of part VII in Fig. 5. Fig. 8 is an enlarged view of part VIII in Fig. 5.

[0062] 2, 3, 4, 5, 7, and 8, the surface of the side region 143 is inclined toward the sixth plane (S6) with respect to the surface of the center region 141. That is, the side region 143 can be formed such that when an imaginary extension line (E1) is drawn from the surface (F1) of the center region 141, the surfaces (F2, F3) intersect with the imaginary extension line (E1).

[0063] The first external angle (θ1) is the angle between the virtual extension line (E1) and the surface (F2) of the first side region 1431. The second external angle (θ2) is the angle between the virtual extension line (E1) and the surface (F3) of the second side region 1432.

[0064] For example, the surface (F2) of the first side region can be defined by a line connecting the end point of the center region and the end point of the first surface. In this case, the end point of the center region can be defined as the point where the center region (F1) extends parallel to the first internal electrode 120 or the second internal electrode 130 and starts to tilt toward the sixth surface (S6), and the end point of the first surface can be defined as the point where the first surface (S1) extends parallel to the thickness direction (T-axis direction) and starts to tilt toward the second surface (S2).

[0065] The surface (F3) of the second side region can be defined by a line connecting the end point of the center region and the end point of the second surface. In this case, the end point of the center region can be defined as the point where the center region (F1) extends parallel to the first internal electrode 120 or the second internal electrode 130 and starts to tilt toward the sixth surface (S6), and the end point of the second surface can be defined as the point where the second surface (S2) extends parallel to the thickness direction (T-axis direction) and starts to tilt toward the first surface (S1).

[0066] In other words, the first outer angle (θ1) may refer to the angle formed between an extension line of the uppermost internal electrode among the internal electrodes shown in the cross-sectional image and the surface of the first side region 1431. The second outer angle (θ2) may refer to the angle formed between the uppermost internal electrode among the internal electrodes shown in the cross-sectional image and the surface of the second side region 1432.

[0067] The first exterior angle (θ1) may be 18° or greater and 20° or less. The second exterior angle (θ2) may also be 18° or greater and 20° or less. The third exterior angle, which is the angle between the surface of the third side region and the surface of the center region, may also be 18° or greater and 20° or less. And the fourth exterior angle, which is the angle between the surface of the fourth side region and the surface of the center region, may also be 18° or greater and 20° or less.

[0068] When the first outer angle, the second outer angle, the third outer angle, and the fourth outer angle are 18° or more and 20° or less, a moisture path that may be formed between the corners of the ceramic body 100 and the internal electrodes can be effectively blocked, thereby improving moisture resistance reliability.

[0069] The first external electrode 200 and the second external electrode 300 are disposed outside the ceramic body 100. The first external electrode 200 is disposed on a first surface (S1) of the ceramic body 100 and can extend to a third surface (S3), a fourth surface (S4), a fifth surface (S5), and a sixth surface (S6).

[0070] The first external electrode 200 includes a first electrode layer 210 and a first conductive resin layer 230 , and the second external electrode 300 includes a second electrode layer 310 and a second conductive resin layer 330 .

[0071] The first electrode layer 210 and the second electrode layer 310 can include conductive metals and glasses.

[0072] As an example, the first electrode layer 210 and the second electrode layer 310 may be made of a conductive metal such as copper (Cu), a copper (Cu) alloy, nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), alloys thereof, or combinations thereof.

[0073] For example, the first electrode layer 210 and the second electrode layer 310 may include a glass-oxide combination composition. For example, the first electrode layer 210 and the second electrode layer 310 may be one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide. The transition metal may be selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni). The alkali metal may be selected from the group consisting of lithium (Li), sodium (Na), and potassium (K). The alkaline earth metal may be one or more selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0074] The first conductive resin layer 230 and the second conductive resin layer 330 may contain a resin and a conductive metal.

[0075] There are no particular limitations on the resin contained in the first conductive resin layer 230 and the second conductive resin layer 330, as long as it has bonding and shock absorption properties and can be mixed with conductive metal powder to form a paste. For example, the resin contained in the first conductive resin layer 230 and the second conductive resin layer 330 can include phenol resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0076] The conductive metal contained in the first conductive resin layer 230 and the second conductive resin layer 330 serves to electrically connect the first electrode layer 210 and the second electrode layer 310. The conductive metal contained in the first conductive resin layer 230 and the second conductive resin layer 330 may have a spherical shape, a flake shape, or a combination thereof.

[0077] The first external electrode 200 may include a first plating layer 250 located outside the first conductive resin layer 230, and the second external electrode 300 may include a second plating layer 350 located outside the second conductive resin layer 330.

[0078] The first plating layer 250 and the second plating layer 350 may include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb), either alone or in alloys thereof. For example, the first plating layer 250 and the second plating layer 350 may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a nickel (Ni) plating layer and a tin (Sn) plating layer stacked sequentially, or a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer stacked sequentially. The plating layer may also include multiple nickel (Ni) plating layers and / or multiple tin (Sn) plating layers.

[0079] The first plating layer 250 and the second plating layer 350 can improve the mountability of the multilayer ceramic capacitor 10 to a substrate, structural reliability, durability against external influences, heat resistance, and equivalent series resistance (ESR).

[0080] Hereinafter, a method for manufacturing the multilayer ceramic capacitor 10 according to one embodiment will be described with reference to FIGS.

[0081] Fig. 9 illustrates a plurality of dielectric green sheets, and Fig. 10 illustrates a laminated structure of a ceramic body using the dielectric green sheets of Fig. 9.

[0082] First, a dielectric paste is prepared for forming a plurality of dielectric green sheets 500. The dielectric paste may include ceramic powder, ceramic additives, an organic solvent, a plasticizer, a dispersant, and a binder.

[0083] For example, the ceramic powder 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. For example, BaTiO3-based dielectric ceramics in which Ca, Zr, etc. are partially dissolved (Ba 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, etc.

[0084] By way of example, the ceramic additives may include transition metal oxides, transition metal carbides, rare earth elements, magnesium (Mg), aluminum (Al), and the like.

[0085] The organic solvent is not particularly limited, and examples thereof include butyl carbitol, acetone, toluene, and ethyl acetate.

[0086] The binder may be a PVB (Polyvinyl Butyral) binder with a glass transition temperature (Tg) of 80°C to 90°C. For example, the binder may further include at least one of polyacrylic acid ester, polymethacrylic acid ester, polyvinyl alcohol, cellulose dielectric, polyalkylene oxide, polyurethane, polyvinyl acetate, polyethylene, ethylene-vinyl acetate copolymer, and polyvinyl chloride. The dielectric paste of this embodiment may include a PVB binder with a glass transition temperature (Tg) of 80°C to 90°C, and the weight of the PVB binder may be 10 wt% to 30 wt% of the ceramic weight in the dielectric paste.

[0087] The dielectric paste can be prepared by a crushing process to ensure uniform powder particles in an organic solvent. For example, ceramic powder, ceramic additives, an organic solvent, a plasticizer, a dispersant, and a binder are filled into a hollow cylindrical crushing mill, and an impeller installed in the crushing mill is rotated at a constant speed to crush the powder by the rotational force. An additional process for separating coarse particles can also be performed, and a filtering process can be performed to remove foreign matter.

[0088] Referring to FIG. 9, the dielectric paste prepared as above is used to manufacture a plurality of dielectric green sheets 500 having a sheet shape with a thickness of several μm by a method such as doctor blade or screen printing.

[0089] For example, the dielectric green sheet 500 can be manufactured by applying a dielectric paste to a film to a certain thickness, filtering and drying the paste, and then removing the film.

[0090] 10, a conductive paste layer 600 is formed on a portion of the surface of the dielectric green sheet 500. After firing, the conductive paste layer 600 becomes the first internal electrode 120 and the second internal electrode 130. The conductive paste layer 600 can be formed by applying a conductive paste containing a conductive metal to the surface of the dielectric green sheet 500 using a doctor blade, screen printing, or other method. For example, the conductive metal can include metals such as Ni, Cu, Ag, Pd, or Au, or alloys thereof.

[0091] For example, the conductive paste may be applied in two patterns on the dielectric green sheet 500. The conductive paste may be applied in a first pattern on the surface of the first dielectric green sheet 510 to form a first conductive paste layer 610. The conductive paste may be applied in a second pattern on the surface of the second dielectric green sheet 520 to form a second conductive paste layer 620.

[0092] The dielectric green sheets 500 are laminated to produce a dielectric green sheet laminate.

[0093] When the first dielectric green sheets 510 and the second dielectric green sheets 520 are alternately laminated, the first conductive paste layers 610 and the second conductive paste layers 620 may be aligned so that some of them overlap and some of them do not. After firing, the first conductive paste layers 610 become the first internal electrodes 120, and the second conductive paste layers 620 become the second internal electrodes 130.

[0094] 10, dielectric green sheets are laminated to manufacture a dielectric green sheet laminate. At this time, the first dielectric green sheet 510 and the second dielectric green sheet 520 are laminated so that the first conductive paste layer 610 and the second conductive paste layer overlap, but at least a portion of them do not overlap.

[0095] A third dielectric green sheet 530, on which no conductive paste layer is formed, is laminated on the first dielectric green sheet 510 and below the second dielectric green sheet 520.

[0096] The dielectric green sheet laminate manufactured as described above is pressed together, and the pressure is applied to the upper surface of the ceramic body 100, i.e., the fifth surface (S5).

[0097] During the lamination or compression bonding of the dielectric green sheet laminate, flow of the dielectric green sheets may occur. Examples of such flow of the dielectric green sheets include pore collapse, binder flow, and particle rearrangement. When such flow of the dielectric green sheets occurs, partial depressions may occur in the first cover layer 140 of the dielectric green sheet laminate. The depressions occur due to the difference in shrinkage rate between the internal electrode layers and the dielectric. This can cause depressions in the side regions 143 of the first cover layer 140, resulting in the formation of slopes. When the dielectric paste contains a PVB binder with a glass transition temperature (Tg) of 80°C to 90°C in an amount of 10 wt% to 30 wt% based on the ceramic weight, the first outer angle (θ1), second outer angle (θ2), third outer angle, and fourth outer angle can each be 18° to 20°.

[0098] Optionally, the dielectric green sheet laminate may be cut so that the first conductive paste layer 610 and the second conductive paste layer 620 are exposed from both cross sections of the dielectric green sheet laminate.

[0099] The ceramic body 100 is manufactured by firing the dielectric green sheet laminate at a high temperature.

[0100] The first external electrode 200 is formed on the cross section of the ceramic body 100 where the first internal electrode 120 is exposed, and the second external electrode 300 is formed on the cross section where the second internal electrode 130 is exposed.

[0101] For example, the first external electrode 200 and the second external electrode 300 may be formed by applying a conductive paste onto the ceramic body 100 and firing the paste, or may be formed by plating. Alternatively, the first external electrode 200 and the second external electrode 300 may be formed by applying a conductive paste onto the dielectric green sheet laminate and then firing the conductive paste together with the dielectric green sheet laminate.

[0102] Specific examples of the invention will be described below.

[0103] [Manufacturing of multilayer ceramic capacitors] (Manufacturing method of the example) A dielectric paste containing barium titanate (BaTiO3) powder was applied onto a carrier film and then dried to produce multiple dielectric green sheets with a thickness of 1.8 μm. The dielectric paste contained 10 wt% to 30 wt% of a PVB binder based on the ceramic weight, and the glass transition temperature (Tg) of the PVB binder was 85°C.

[0104] A conductive paste containing nickel was applied onto the dielectric green sheet using a screen printing method.

[0105] Approximately 100 layers of dielectric green sheets coated with conductive paste were stacked, and five layers of dielectric green sheets not coated with conductive paste were stacked on top and bottom to produce a dielectric green sheet laminate.

[0106] The dielectric green sheet laminate was subjected to 1000 kgf / cm at 85°C. 2 The mixture was subjected to isostatic pressing under the pressure conditions.

[0107] The dielectric green sheet laminate after the compression bonding was cut into individual chips, and then the binder was removed by maintaining the chips at 230° C. for 60 hours in an air atmosphere.

[0108] Then, at 1200°C, the internal electrode was heated to 10°C, which is lower than the Ni / NiO equilibrium oxygen partial pressure, to prevent oxidation. -11 atm~10 -10 The material was fired in a reducing atmosphere under an oxygen partial pressure of 1 atm.

[0109] Next, processes such as external electrode formation and plating were carried out to manufacture a multilayer capacitor (L×W×T=3.2 mm×1.6 mm×1.6 mm).

[0110] (Manufacturing method of Comparative Example 1 group) A dielectric paste containing 10 wt% to 30 wt% of a PVB binder with a glass transition temperature (Tg) of 70° C. based on the ceramic weight was prepared. Except for this, a multilayer ceramic capacitor was manufactured in the same manner as in Example 1.

[0111] (Manufacturing method of Comparative Example 2 group) A dielectric paste containing 10 wt% to 30 wt% of a PVB binder with a glass transition temperature (Tg) of 75° C. based on the ceramic weight was prepared. Except for this, a multilayer ceramic capacitor was manufactured in the same manner as in Example 1.

[0112] [Moisture resistance load test] After manufacturing a plurality of multilayer ceramic capacitors of the Example and Comparative Examples 1 and 2, the angles of the first outer angles were measured. Most of the first outer angles of the Example were in the range of 18° to 20°. Most of the first outer angles of Comparative Example 1 were in the range of 15° to 17°, and most of the first outer angles of Comparative Example 2 were in the range of 21° to 23°.

[0113] 1200 pieces of each of the multilayer ceramic capacitors manufactured according to the examples were selected from Example 1, Example 2, and Example 3 according to the angle of the first exterior angle.

[0114] 1200 pieces of each of the multilayer ceramic capacitors manufactured in Comparative Example 1 group were selected for Comparative Example 1, Comparative Example 2, and Comparative Example 3 according to the angle of the first exterior angle.

[0115] 1200 pieces of each of the multilayer ceramic capacitors manufactured in Comparative Example 2 were selected for Comparative Example 4, Comparative Example 5, and Comparative Example 6 according to the angle of the first exterior angle.

[0116] The multilayer ceramic capacitors of Examples 1 to 3 and Comparative Examples 1 to 6 classified as above were subjected to a humidity load test.

[0117] The humidity load test was carried out as follows.

[0118] First, three substrates were prepared for each classification of multilayer ceramic capacitors as described above, and 400 multilayer ceramic capacitors belonging to the same classification were mounted on each substrate.

[0119] A current of 6.3V was applied to each board for 8 hours under conditions of 85°C and 85% humidity. The number of multilayer ceramic capacitors that failed was counted using the 8585 humidity test equipment (the 8585 humidity test equipment displays a signal if a degraded chip is detected, so it is possible to determine whether any multilayer ceramic capacitors failed the humidity load test).

[0120] The results of the above experiments are summarized in Table 1.

[0121] [Table 1]

[0122] As shown in Table 1, all multilayer ceramic capacitors with a first outer angle between 18° and 20° passed the humidity reliability test standard. However, when the first outer angle was less than 18° or more than 20°, some capacitors failed to pass the humidity reliability test standard.

[0123] As described above, in the multilayer ceramic capacitor of the present disclosure, the side region of the first cover layer is tilted at an angle of 18° to 20°, thereby blocking the path of moisture penetration into the internal electrodes, thereby improving the moisture resistance reliability of the multilayer ceramic capacitor.

[0124] Although the above describes a preferred embodiment of the present disclosure, the present disclosure is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and it is to be understood that these also fall within the scope of the present disclosure. [Explanation of symbols]

[0125] 10 Multilayer ceramic capacitor 100 ceramic body 110 dielectric layer 120 1st internal electrode 130 2nd internal electrode 140 First Cover Layer 141 Center Area 143 Side Area 1431 First Side Area 1432 Second Side Area 1433 Third Side Area 1434 4th Side Area 150 Second cover layer 200 1st external electrode 210 1st electrode layer 230 First conductive resin layer 250 First plating layer 300 2nd external electrode 310 Second electrode layer 330 Second conductive resin layer 350 Second plating layer 500 Dielectric Green Sheet

Claims

1. a dielectric layer, a first internal electrode and a second internal electrode facing each other with the dielectric layer interposed therebetween; and a first cover layer disposed on at least one of the first internal electrode and the second internal electrode; the first cover layer is divided into a center region and a side region located outside the center region, The multilayer ceramic capacitor has a surface of the side region that is inclined downward at an angle of 18° to 20° with respect to the surface of the center region.

2. The multilayer ceramic capacitor according to claim 1 , wherein the side regions are arranged to surround the center region.

3. The multilayer ceramic capacitor according to claim 1 , wherein the center region is located above an active region where the first internal electrodes and the second internal electrodes overlap.

4. The multilayer ceramic capacitor according to claim 3 , wherein the side region is located on a margin region surrounding the active region.

5. the center region does not overlap the margin region; and The multilayer ceramic capacitor of claim 4 , wherein the side regions do not overlap the active region.

6. 2. The multilayer ceramic capacitor according to claim 1, wherein the inclination is an angle at which the surface of the side region is inclined with respect to an extension line of an uppermost internal electrode located at the top of the first internal electrode and the second internal electrode.

7. a second cover layer located below the dielectric layer, the first internal electrode, and the second internal electrode; The multilayer ceramic capacitor according to claim 1 , wherein the portion of the second cover layer overlapping the side region has the inclination with respect to a line parallel to the side region.

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