Multilayer ceramic capacitor

Abstract

One embodiment of the present invention aims to provide a multilayer ceramic capacitor that can prevent crack formation and dielectric breakdown in the dielectric layer. [Solution] A multilayer ceramic capacitor according to one embodiment includes a body having a first surface and a second surface that are opposite to each other in a first direction, and a plurality of internal electrodes stacked in the first direction with a dielectric layer interposed between them, and an external electrode disposed outside the body, wherein the body includes a first outer region facing the first surface, a second outer region facing the second surface, and an inner region between the first outer region and the second outer region, the internal electrodes of the first outer region and the internal electrodes of the second outer region are thinner than the internal electrodes of the inner region, and the dielectric layer of the first outer region and the dielectric layer of the second outer region may be thicker than the dielectric layer of the inner region.

Description

[Technical Field]

[0001] This disclosure relates to multilayer ceramic capacitors. [Background technology]

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

[0003] A multilayer ceramic capacitor may include a body comprising multiple dielectric layers and multiple internal electrodes, and external electrodes positioned outside the body and connected to the internal electrodes. A multilayer ceramic capacitor may fail if cracks develop in the dielectric layers or dielectric breakdown occurs. [Overview of the project] [Problems that the invention aims to solve]

[0004] One embodiment of the present invention aims to provide a multilayer ceramic capacitor that can prevent crack formation and dielectric breakdown in the dielectric layer. Solution to the problem

[0005] A multilayer ceramic capacitor according to one embodiment of the present invention includes a body having a first surface and a second surface that are opposite to each other in a first direction, and a plurality of internal electrodes stacked in the first direction with a dielectric layer interposed therebetween, and an external electrode disposed outside the body, wherein the body includes a first outer region facing the first surface, a second outer region facing the second surface, and an inner region between the first outer region and the second outer region, the internal electrodes of the first outer region and the internal electrodes of the second outer region are thinner than the internal electrodes of the inner region, and the dielectric layer of the first outer region and the dielectric layer of the second outer region may be thicker than the dielectric layer of the inner region.

[0006] The ratio of the thickness of the dielectric layer in the first outer region to the thickness of the dielectric layer in the inner region may be greater than 1 and less than or equal to 3.

[0007] The ratio of the thickness of the dielectric layer in the second outer region to the thickness of the dielectric layer in the inner region may be greater than 1 and less than or equal to 3.

[0008] The first outer region includes a first internal electrode closest to the first surface, a second internal electrode facing the first internal electrode, and a first dielectric layer between the first internal electrode and the second internal electrode, the thickness of which the first dielectric layer may be thicker than that of the dielectric layer in the inner region.

[0009] The second outer region includes a third internal electrode closest to the second surface, a fourth internal electrode facing the third internal electrode, and a second dielectric layer between the third and fourth internal electrodes, the thickness of which the second dielectric layer may be thicker than that of the dielectric layer in the inner region.

[0010] The number of internal electrodes in the first outer region may be less than the number of internal electrodes in the inner region.

[0011] The number of internal electrodes in the second outer region may be less than the number of internal electrodes in the inner region.

[0012] The sum of the number of internal electrodes in the first outer region and the number of internal electrodes in the second outer region may be less than the number of internal electrodes in the inner region.

[0013] The body may further include a first cover layer positioned outside the first outer region in the first direction, and a second cover layer positioned outside the second outer region in the first direction.

[0014] The multilayer ceramic capacitor may further include a plating layer covering the external electrodes.

[0015] The plating layer may include a first layer covering the external electrode, a second layer covering the first layer, and a third layer covering the second layer.

[0016] The first layer may contain nickel (Ni), the second layer may contain copper (Cu), and the third layer may contain tin (Sn). [Effects of the Invention]

[0017] According to the multilayer ceramic capacitor of this embodiment, crack formation and dielectric breakdown can be prevented by making the thickness of the dielectric layer in the outer region of the body in the stacking direction thicker than the thickness of the dielectric layer in the inner region. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a schematic perspective view showing a multilayer ceramic capacitor according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view taken along the line I-I' in Figure 1. [Figure 3] Figure 3 is a cross-sectional view taken along the line II-II' in Figure 1. [Figure 4] Figure 4 is an enlarged view of area A in Figure 2. [Figure 5] Figure 5 is an enlarged view showing area B in Figure 2. [Figure 6] Figure 6 is an enlarged view of region C in Figure 2.

Best Mode for Carrying Out the Invention

[0019] Hereinafter, referring to the attached drawings, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. In the drawings, parts unnecessary for explanation for clearly explaining the present invention are omitted, and the same reference numerals are given to the same or similar components throughout the specification. Also, in the attached drawings, some components are exaggerated, omitted, or shown schematically, and the size of each component does not completely reflect the actual size.

[0020] The attached drawings are only for facilitating understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and it must be understood that they include any modifications, equivalents, or alternatives included in the idea and technical scope of the present invention.

[0021] Terms including ordinal numbers such as first, second, etc. can be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0022] Also, when a part such as a layer, film, region, plate, etc. is “above” another part, this includes not only the case where it is “directly above” the other part but also the case where there are other parts in between. Conversely, when a part is “directly above” another part, it means that there are no other parts in between. Also, being “above” a reference part means being located above or below the reference part, and it does not necessarily mean being located “above” in the direction opposite to gravity.

[0023] Throughout the specification, terms such as “includes” or “have” are intended to specify the presence of features, figures, steps, actions, components, parts, or combinations thereof described in the specification, and should not be understood to preemptively exclude the presence or possibility of adding one or more other features, figures, steps, actions, components, parts, or combinations thereof. Therefore, when a part “includes” a component, this means that, unless otherwise stated, it does not exclude other components and may further include other components.

[0024] Furthermore, throughout the specification, "on a plane" refers to the view of the part in question from above, and "on a cross-section" refers to the view of the cross-section obtained by cutting the part in question perpendicularly from the side.

[0025] Furthermore, throughout the specification, the term "connected" does not only mean that two or more components are directly connected, but may also mean that two or more components are indirectly connected through other components, that they are not only physically connected but also electrically connected, or that they are a single unit, even though they are referred to by different names depending on their location or function.

[0026] Figure 1 is a schematic perspective view showing a multilayer ceramic capacitor according to one embodiment, Figure 2 is a cross-sectional view taken along the line I-I' in Figure 1, and Figure 3 is a cross-sectional view taken along the line II-II' in Figure 1.

[0027] Referring to Figures 1, 2, and 3, the multilayer ceramic capacitor 1000 according to this embodiment includes a body 110, a first external electrode 120, a second external electrode 130, a plurality of dielectric layers 140, a plurality of first internal electrodes 150, and a plurality of second internal electrodes 160.

[0028] First, to clearly explain this embodiment, let's define the directions: the L-axis, W-axis, and T-axis shown in the drawing represent the length, width, and thickness directions of the multilayer ceramic capacitor 1000, respectively.

[0029] The thickness direction (T-axis direction) may be perpendicular to the wide surface (circumferential surface) of the sheet-shaped component. For example, the thickness direction (T-axis direction) can be used as the same concept as the direction in which the dielectric layer 140 is stacked.

[0030] The length direction (L-axis direction) is parallel to the wide surface (circumferential surface) of the sheet-shaped component and may intersect (or be perpendicular to) the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be the direction in which the first external electrode 120 and the second external electrode 130 face each other.

[0031] The width direction (W-axis direction) is a direction parallel to the wide surface (circumferential surface) of the sheet-shaped component, and may simultaneously intersect (or be perpendicular to) the thickness direction (T-axis direction) and the length direction (L-axis direction).

[0032] The body 110 may be approximately hexahedral in shape, but this embodiment is not limited to this. Due to shrinkage during sintering, the body 110 may not be a perfect hexahedron, but may have a substantially hexahedral shape. For example, the body 110 may be approximately a right hexahedron, but the corners and vertices may have a rounded shape.

[0033] In this embodiment, for the sake of explanation, surfaces facing each other in the length direction (L-axis direction) are defined as the first surface S1 and the second surface S2, surfaces facing each other in the width direction (W-axis direction) and connecting the first surface S1 and the second surface S2 are defined as the third surface S3 and the fourth surface S4, and surfaces facing each other in the thickness direction (T-axis direction) and connecting the first surface S1 and the second surface S2 are defined as the fifth surface S5 and the sixth surface S6.

[0034] Therefore, the first direction in which the first surface S1 and the second surface S2 face each other is the length direction (L-axis direction), and the second and third directions, which are perpendicular to the first direction and perpendicular to each other, may be the thickness direction (T-axis direction) and the width direction (W-axis direction) or the width direction (W-axis direction) and the thickness direction (T-axis direction), respectively.

[0035] The length of body 110 may represent the maximum length among multiple line segments parallel to the length direction (L-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the cross section (L-axis direction) of body 110 at the center of the width direction (W-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the length direction (L-axis direction) as shown in the aforementioned cross section photograph. On the other hand, the length of body 110 may represent the minimum length among multiple line segments parallel to the length direction (L-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the length direction (L-axis direction) as shown in the aforementioned cross section photograph. On the other hand, the length of body 110 may represent the arithmetic mean of the lengths of at least two line segments parallel to the length direction (L-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the length direction (L-axis direction) as shown in the aforementioned cross section photograph.

[0036] The thickness of body 110 may represent the maximum length of a plurality of line segments parallel to the thickness direction (T-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the 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 body 110, by connecting the two outermost boundary lines of body 110 that are opposite each other in the thickness direction (T-axis direction) as shown in the aforementioned cross section photograph. On the other hand, the thickness of body 110 may represent the minimum length of a plurality of line segments parallel to the thickness direction (T-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the thickness direction (T-axis direction) as shown in the aforementioned cross section photograph. On the other hand, the thickness of body 110 may represent the arithmetic mean of the lengths of at least two line segments parallel to the thickness direction (T-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the thickness direction (T-axis direction) as shown in the aforementioned cross section photograph.

[0037] The width of body 110 may represent the maximum length of a plurality of line segments parallel to the width direction (W-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the cross section in the length direction (L-axis direction) - width direction (W-axis direction) at the center of body 110 in the thickness direction (T-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the width direction (W-axis direction) as shown in the aforementioned cross section photograph. On the other hand, the width of body 110 may represent the minimum length of a plurality of line segments parallel to the width direction (W-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the width direction (W-axis direction) as shown in the aforementioned cross section photograph. On the other hand, the width of body 110 may represent the arithmetic mean of the lengths of at least two line segments parallel to the width direction (W-axis direction), by connecting the two outermost boundary lines of body 110 that are opposite each other in the width direction (W-axis direction) as shown in the aforementioned cross section photograph.

[0038] The body 110 may include a plurality of dielectric layers 140 stacked in the thickness direction (T-axis direction). The boundaries between the dielectric layers 140 may be unclear. For example, the boundaries between the dielectric layers 140 may be difficult to confirm without using a scanning electron microscope (SEM), and the plurality of dielectric layers 140 may appear as a single integrated structure.

[0039] The first internal electrode 150 and the second internal electrode 160 may be stacked alternately with the dielectric layer 140 in between. Such a stacked structure may be repeated within the body 110, and the internal electrode closest to the fifth surface S5 of the body 110 may be either the first internal electrode 150 or the second internal electrode 160. Similarly, the internal electrode closest to the sixth surface S6 of the body 110 may be either the first internal electrode 150 or the second internal electrode 160.

[0040] The first internal electrode 150 and the second internal electrode 160 have different polarities, but they can be electrically insulated from each other by the dielectric layer 140 placed between them.

[0041] The first internal electrode 150 and the second internal electrode 160 may be formed by printing a conductive paste containing a metal onto the surface of the dielectric layer 140. For example, the internal electrodes can be formed by printing a conductive paste containing nickel (Ni) or a nickel (Ni) alloy onto the surface of the dielectric layer using screen printing or gravure printing. However, this embodiment is not limited to this.

[0042] When a voltage is applied to the first external electrode 120 and the second external electrode 130, charge accumulates between the first internal electrode 150 and the second internal electrode 160. In other words, capacitance can be obtained between the first internal electrode 150, which is electrically connected to the first external electrode 120, and the second internal electrode 160, which is electrically connected to the second external electrode 130. The capacitance of the multilayer ceramic capacitor 1000 is proportional to the overlapping area of ​​the first internal electrode 150 and the second internal electrode 160, which overlap each other along the thickness direction (T-axis direction).

[0043] In other words, the multilayer ceramic capacitor 1000 may include an active region and a margin region. The active region may refer to the region where the first internal electrode 150 and the second internal electrode 160 overlap along the thickness direction (T-axis direction), and the margin region may refer to the region between the active region and the first surface S1 of the body 110 and the region between the active region and the second surface S2 of the body 110. On the other hand, the region between the active region and the third surface S3 of the body 110 and the region between the active region and the fourth surface S4 of the body 110 may also be referred to as a margin region.

[0044] A first cover layer 143 and a second cover layer 145 may be arranged on the outer side of the active region in the thickness direction (T-axis direction).

[0045] The first cover layer 143 is positioned between the fifth surface S5 of the body 110 and the internal electrode closest to it. The second cover layer 145 is positioned between the sixth surface S6 of the body 110 and the internal electrode closest to it.

[0046] That is, the first cover layer 143 may be disposed on top of the internal electrode at the uppermost part within the body 110, and the second cover layer 145 may be disposed below the internal electrode at the lowermost part. The first cover layer 143 and the second cover layer 145 can have the same composition as the dielectric layer 140. One or more dielectric layers can be laminated on the outer surfaces of the uppermost internal electrode and the lowermost internal electrode, respectively, to form the first cover layer 143 and the second cover layer 145. On the other hand, the first cover layer 143 and the second cover layer 145 can have a composition different from that of the dielectric layer 140.

[0047] The first cover layer 143 and the second cover layer 145 can serve to prevent damage to the first internal electrode 150 and the second internal electrode 160 due to physical or chemical stress.

[0048] The dielectric layer 140 can include a high dielectric constant ceramic material. For example, the ceramic material can include a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. Further, these components can further include auxiliary components such as manganese (Mn) compounds, iron (Fe) compounds, chromium (Cr) compounds, cobalt (Co) compounds, nickel (Ni) compounds, etc. For example, the dielectric layer is (Ba 1-x Ca x )TiO3 (0 < x < 1), Ba(Ti 1-y Ca y )O3 (0 < y < 1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (0 < x < 1, 0 < y < 1) or Ba(Ti 1-y Zr y )O3 (0 < y < 1), etc., but the present invention is not limited thereto.

[0049] Furthermore, the dielectric layer 140 may further contain one or more of the following: ceramic additives, organic solvents, plasticizers, binders, and dispersants. The ceramic additives may be, for example, transition metal oxides or carbides, rare earth elements, magnesium (Mg), or aluminum (Al).

[0050] The first external electrode 120 and the second external electrode 130 are positioned outside the body 110.

[0051] The first external electrode 120 is positioned on the first surface S1 of the body 110 and may extend to the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6. The second external electrode 130 is positioned on the second surface S2 of the body 110 and may extend to the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6. In other embodiments, the first external electrode 120 and the second external electrode 130 may extend to a portion of at least one of the fifth surface S5 and sixth surface S6.

[0052] The first external electrode 120 includes a first connecting portion 121, a first band portion 123, and a first corner portion 125.

[0053] The first connection portion 121 covers the first surface S1 of the body 110 and is connected to a plurality of first internal electrodes 150, thereby being electrically coupled.

[0054] In other embodiments, the first connecting portion 121 can cover a portion of the first surface S1 of the body 110.

[0055] The first band portion 123 extends from the first connection portion 121 and covers at least a portion of the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6 of the body 110. The first band portion 123 can allow the first external electrode 120 to be more firmly fixed to the body 110.

[0056] The first corner portion 125 may be the portion that connects the first connecting portion 121 and the first band portion 123.

[0057] The second external electrode 130 includes a second connecting portion 131, a second band portion 133, and a second corner portion 135, respectively.

[0058] The second connection portion 131 covers the second surface S2 of the body 110 and is connected to a plurality of second internal electrodes 160, thereby being electrically coupled.

[0059] In other embodiments, the second connecting portion 131 can cover a portion of the second surface S2 of the body 110.

[0060] The second band portion 133 extends from the second connecting portion 131 and covers at least a portion of the third surface S3, fourth surface S4, fifth surface S5, and sixth surface S6 of the body 110. The second band portion 133 can allow the second external electrode 130 to be more firmly fixed to the body 110.

[0061] The second corner portion 135 may be the portion that connects the second connecting portion 131 and the second band portion 133.

[0062] Based on an optical microscope or scanning electron microscope (SEM) photograph of the cross section in the length direction (L-axis direction) - thickness direction (T-axis direction) at the center of the multilayer ceramic capacitor 1000 in the width direction (W-axis direction), the first connection portion 121 and the second connection portion 131 of the multilayer ceramic capacitor 1000 shown in the aforementioned cross section photograph may have a shape approximately parallel to the thickness direction (T-axis direction), the first band portion 123 and the second band portion 133 may have a shape approximately parallel to the length direction (L-axis direction), and the first corner portion 125 and the second corner portion 135 may have a curved shape. The aforementioned curved shape may also be a curved shape having a tangent whose slope changes in the direction parallel to the thickness direction (T-axis direction) in the direction parallel to the length direction (L-axis direction) (or in the opposite direction).

[0063] The first external electrode 120 and the second external electrode 130 may be formed from conductive materials such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), chromium (Cr), titanium (Ti), or alloys thereof, but are not limited thereto.

[0064] As another example, the first external electrode 120 and the second external electrode 130 may include metal and glass. The metal may be a conductive metal including, for example, copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), or alloys thereof. The glass component included in the external electrode may be a composition of mixed oxides. The glass component may include, for example, silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, alkaline earth metal oxide, or combinations thereof. Here, the transition metal may be selected from zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), or nickel (Ni); the alkali metal may be selected from lithium (Li), sodium (Na), or potassium (K); and the alkaline earth metal may be selected from magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba). The method for forming such an external electrode is not particularly limited. For example, it can be formed by dipping the body into a conductive paste containing metal and glass, or by printing the conductive paste onto the surface of the body using screen printing or gravure printing. In addition, various methods can be used, such as coating the surface of the body with conductive paste or transferring a dried film of the conductive paste to a laminate.

[0065] On the other hand, the first external electrode 120 may be covered by the first plating layer 180, and the second external electrode 130 may be covered by the second plating layer 190.

[0066] The first plating layer 180 and the second plating layer 190 may both consist of multiple layers. For example, the first plating layer 180 may include a first layer 181 covering the first external electrode 120, a second layer 183 covering the first layer 181, and a third layer 185 covering the second layer 183. The first layer may contain nickel (Ni), the second layer may contain copper (Cu), and the third layer may contain tin (Sn), but this embodiment is not limited thereto.

[0067] Furthermore, the second plating layer 190 may include a first layer 191 covering the second external electrode 130, a second layer 193 covering the first layer 191, and a third layer 195 covering the second layer 193. The first layer 191 may contain nickel (Ni), the second layer 193 may contain copper (Cu), and the third layer 195 may contain tin (Sn), but this embodiment is not limited thereto.

[0068] Figure 4 is an enlarged view of area A in Figure 2, Figure 5 is an enlarged view of area B in Figure 2, and Figure 6 is an enlarged view of area C in Figure 2.

[0069] Referring to Figures 2, 4, 5, and 6, the body 110 may include a first outer region 111, a second outer region 112, and an inner region 113 along the thickness direction (T-axis direction).

[0070] The first outer region 111 is the region that faces the fifth surface S5 of the body 110 and is in contact with the first cover layer 143.

[0071] The first outer region 111 includes a first internal electrode 150a, a second internal electrode 160a, and a dielectric layer 140a.

[0072] The first internal electrode 150a may be the internal electrode closest to the fifth surface S5 of the body 110, and the second internal electrode 160a may be the internal electrode facing the first internal electrode 150a. The dielectric layer 140a may be placed between the first internal electrode 150a and the second internal electrode 160a.

[0073] Figures 2 and 3 show that the first outer region 111 includes three internal electrodes and three dielectric layers, but this embodiment is not limited to this.

[0074] The second outer region 112 is the region that faces the sixth surface S6 of the body 110 and is in contact with the second cover layer 145.

[0075] The second outer region 112 includes the first internal electrode 150b, the second internal electrode 160b, and the dielectric layer 140b.

[0076] The first internal electrode 150b may be the internal electrode closest to the sixth surface S6 of the body 110, and the second internal electrode 160b may be the internal electrode facing the first internal electrode 150b. The dielectric layer 140b may be placed between the first internal electrode 150b and the second internal electrode 160b.

[0077] Figures 2 and 3 show that the second outer region 112 includes three internal electrodes and three dielectric layers, but this embodiment is not limited to this.

[0078] The inner region 113 is the region between the first outer region 111 and the second outer region 112. The inner region 113 includes the first internal electrode 150c, the second internal electrode 160c, and the dielectric layer 140c.

[0079] Figures 2 and 3 show that the inner region 113 includes four internal electrodes and three dielectric layers, but this embodiment is not limited to this.

[0080] The number of internal electrodes in the first outer region 111 may be less than the number of internal electrodes in the inner region 113. The number of internal electrodes in the second outer region 112 may be less than the number of internal electrodes in the inner region 113. Furthermore, the sum of the number of internal electrodes in the first outer region 111 and the number of internal electrodes in the second outer region 112 may be less than the number of internal electrodes in the inner region 113.

[0081] The thickness t1 of the internal electrodes 150a and 160a in the first outer region 111 is thinner than the thickness t3 of the internal electrodes 150c and 160c in the inner region 113. The thickness t2 of the internal electrodes 150b and 160b in the second outer region 112 is thinner than the thickness t3 of the internal electrodes 150c and 160c in the inner region 113.

[0082] Here, the thickness of the internal electrode may refer to the average thickness of a single internal electrode placed between two dielectric layers. The average thickness of the internal electrode may also be the arithmetic mean of the thickness of a single internal electrode shown in the aforementioned cross-sectional photograph, measured at 30 points evenly spaced in the length direction (L-axis direction), based on a 10,000x magnification scanning electron microscope (SEM) photograph of the length direction (L-axis direction) - thickness direction (T-axis direction) cross-section at the center of the width direction (W-axis direction) of the body 110. These 30 points can be designated as the aforementioned active region. The average thickness of the internal electrode can be further generalized by deriving the arithmetic mean of the measured values ​​after measuring the average thickness of 10 (or fewer) internal electrodes in this manner.

[0083] The dielectric layer 140a of the first outer region 111 is thicker than the dielectric layer 140c of the inner region 113.

[0084] The ratio d1 / d3 of the thickness d1 of the dielectric layer 140a of the first outer region 111 to the thickness d3 of the dielectric layer 140c of the inner region 113 may be greater than 1 and less than or equal to 3. For example, the thickness d3 of the dielectric layer 140c of the inner region 113 may be 0.88 μm, and the thickness d1 of the dielectric layer 140a of the first outer region 111 may be 0.93 μm.

[0085] The dielectric layer 140b of the second outer region 112 is thicker than the dielectric layer 140c of the inner region 113.

[0086] The ratio d2 / d3 of the thickness d3 of the dielectric layer 140c in the inner region 113 to the thickness d2 of the dielectric layer 140b in the second outer region 112 may be greater than 1 and less than or equal to 3. For example, the thickness d3 of the dielectric layer 140c in the inner region 113 may be 0.88 μm, and the thickness d2 of the dielectric layer 140b in the second outer region 112 may be 0.93 μm.

[0087] Here, the thickness of the dielectric layer may refer to the average thickness of a single dielectric layer placed between two internal electrodes. The average thickness of the dielectric layer may also be the arithmetic mean of the thickness of a single dielectric layer shown in the aforementioned cross-sectional photograph, measured at 30 points evenly spaced in the length direction (L-axis direction), based on a 10,000x magnification scanning electron microscope (SEM) photograph of the length direction (L-axis direction) - thickness direction (T-axis direction) cross-section at the center of the width direction (W-axis direction) of the body 110. These 30 points can be designated as the aforementioned active region. The average thickness of the dielectric layer can be further generalized by deriving the arithmetic mean of the measured values ​​after measuring the average thickness of 10 (or fewer) dielectric layers in this manner.

[0088] On the other hand, the dielectric layer 140a of the first outer region 111 can be made thicker than the dielectric layer 140c of the inner region 113, and the thickness t1 of the internal electrodes 150a and 160a of the first outer region 111 can be made thinner than the thickness t3 of the internal electrodes 150c and 160c of the inner region 113. The dielectric layer 140b of the second outer region 112 can be made thicker than the dielectric layer 140c of the inner region 113, and the thickness t2 of the internal electrodes 150b and 160b of the second outer region 112 can be made thinner than the thickness t3 of the internal electrodes 150c and 160c of the inner region 113. In particular, the thickness of the internal electrodes 150a and 160a of the first outer region 111 can be decreased by the amount by which the thickness of the dielectric layer 140a of the first outer region 111 has increased, and the thickness of the internal electrodes 150b and 160b of the second outer region 112 can be decreased by the amount by which the thickness of the dielectric layer 140b of the second outer region 112 has increased. In other words, the increase in the thickness of the dielectric layer and the decrease in the thickness of the internal electrodes can be offset. Therefore, the overall thickness of the multilayer ceramic capacitor can be maintained within a certain range.

[0089] Generally, cracks are most likely to form or dielectric breakdown may occur in the dielectric layer closest to the outer surface in the thickness direction (T-axis direction) of a multilayer ceramic capacitor.

[0090] According to this embodiment, the thickness of the dielectric layer in the first outer region 111 near the fifth surface S5 of the body 110 and the second outer region 112 near the sixth surface S6 of the body 110 is greater than the thickness of the dielectric layer in the inner region 113. Therefore, crack formation and dielectric breakdown of the dielectric layers in the first outer region 111 and the second outer region 112 can be prevented. As a result, the multilayer ceramic capacitor according to this embodiment can have improved reliability.

[0091] [Experimental Example: Insulation Resistance of Multilayer Ceramic Capacitors] Fifty multilayer ceramic capacitors were manufactured for both the examples and comparative examples. These were then mounted on substrates and subjected to high-temperature load testing under conditions of 125°C, 1.2 atm, 95% RH, and rated voltage. Failure was defined as a capacitor where the insulation resistance fell below 10 kΩ. The mean time to failure (MTTF) was calculated from this failure time. The results are summarized in Table 1.

[0092] [Table 1]

[0093] Referring to Table 1, the mean time to failure of the multilayer ceramic capacitor according to the embodiment was 11.83 hours, while the mean time to failure of the multilayer ceramic capacitor according to the comparative example was 8.2 hours. In other words, the mean time to failure of the multilayer ceramic capacitor according to the embodiment was longer than that of the multilayer ceramic capacitor according to the comparative example. This is thought to be because the dielectric layers in the first outer region and the second outer region are thicker than the dielectric layer in the inner region, thus preventing crack formation and dielectric breakdown of the dielectric layer.

[0094] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, description of the invention, and attached drawings, and these also naturally fall within the scope of the present invention. [Explanation of symbols]

[0095] 1000: Multilayer ceramic capacitor 110: Body 120: 1st external electrode 130: 2nd external electrode 140, 140a, 140b, 140c: Dielectric layer 143: First Cover Layer 145: Second Cover Layer 150, 150a, 150b, 150c: 1st internal electrode 160, 160a, 160b, 160c: 2nd internal electrode 180: First plating layer 190: Second plating layer 181, 191: 1st layer 183, 193: 2nd layer 185, 195: 3rd layer

Claims

1. A body having a first surface and a second surface that are opposite to each other in a first direction, and including a plurality of internal electrodes stacked in the first direction with a dielectric layer interposed between them, The external electrode is located outside the body, and includes The aforementioned body is The first outer region facing the first surface, The second outer region facing the second surface, and The inner region between the first outer region and the second outer region Includes, The internal electrodes of the first outer region and the internal electrodes of the second outer region are thinner than the internal electrodes of the inner region. A multilayer ceramic capacitor in which the dielectric layer of the first outer region and the dielectric layer of the second outer region are thicker than the dielectric layer of the inner region.

2. The multilayer ceramic capacitor according to claim 1, wherein the ratio of the thickness of the dielectric layer in the first outer region to the thickness of the dielectric layer in the inner region is greater than 1 and less than or equal to 3.

3. The multilayer ceramic capacitor according to claim 2, wherein the ratio of the thickness of the dielectric layer in the second outer region to the thickness of the dielectric layer in the inner region is greater than 1 and less than or equal to 3.

4. The first outer region includes a first internal electrode closest to the first surface, a second internal electrode facing the first internal electrode, and a first dielectric layer between the first internal electrode and the second internal electrode. The multilayer ceramic capacitor according to claim 1, wherein the thickness of the first dielectric layer is greater than that of the dielectric layer in the inner region.

5. The second outer region includes a third internal electrode closest to the second surface, a fourth internal electrode facing the third internal electrode, and a second dielectric layer between the third internal electrode and the fourth internal electrode. The multilayer ceramic capacitor according to claim 4, wherein the thickness of the second dielectric layer is greater than that of the dielectric layer in the inner region.

6. The multilayer ceramic capacitor according to claim 1, wherein the number of internal electrodes in the first outer region is less than the number of internal electrodes in the inner region.

7. The multilayer ceramic capacitor according to claim 6, wherein the number of internal electrodes in the second outer region is less than the number of internal electrodes in the inner region.

8. The multilayer ceramic capacitor according to claim 7, wherein the sum of the number of internal electrodes in the first outer region and the number of internal electrodes in the second outer region is less than the number of internal electrodes in the inner region.

9. The aforementioned body is A first cover layer positioned outside the first outer region in the first direction, and The second cover layer is located outside the second outer region in the first direction. The multilayer ceramic capacitor according to claim 1, further comprising:

10. The multilayer ceramic capacitor according to claim 1, further comprising a plating layer covering the external electrode.

11. The aforementioned plating layer is The first layer covering the external electrode, A second layer covering the first layer, and A third layer covering the aforementioned second layer A multilayer ceramic capacitor according to claim 10, including the above.

12. The first layer contains nickel (Ni), The second layer contains copper (Cu), The multilayer ceramic capacitor according to claim 11, wherein the third layer contains tin (Sn).

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