Multilayer ceramic capacitor

Abstract

The present disclosure provides a multilayer ceramic capacitor. The multilayer ceramic capacitor includes: a body including a plurality of internal electrodes and a plurality of dielectric layers alternately stacked in a first direction with each dielectric layer interposed between adjacent ones of the plurality of internal electrodes, and having a first surface and a second surface opposite to each other in the first direction; an external electrode disposed on an outer side of the main body; 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, in which the inner electrode in the first outer region and the inner electrode in the second outer region are thinner than the inner electrode in the inner region, and the dielectric layer in the first outer region and the dielectric layer in the second outer region are thicker than the dielectric layer in the inner region.

Description

Technical Field

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

[0002] Electronic components using ceramic materials include capacitors, inductors, piezoelectric devices, rheostats, and thermistors. Among these ceramic electronic components, multilayer ceramic capacitors (MLCCs) have the advantages of small size, guaranteed high capacitance, and ease of installation, and therefore can be used in a variety of electronic devices.

[0003] A multilayer ceramic capacitor may include a body and an outer electrode. The body includes multiple dielectric layers and multiple inner electrodes, and the outer electrodes are disposed on the outer side of the body and connected to the inner electrodes. A multilayer ceramic capacitor may fail when cracks form in the dielectric layers or when electrical breakdown occurs. Summary of the Invention

[0004] This disclosure attempts to provide a multilayer ceramic capacitor capable of preventing cracking and electrical breakdown in the dielectric layer.

[0005] A multilayer ceramic capacitor according to some embodiments of the present disclosure may include: a body comprising a plurality of internal electrodes and a plurality of dielectric layers alternately stacked in a first direction, each dielectric layer being between adjacent internal electrodes among the plurality of internal electrodes, and the body having a first surface and a second surface opposite to each other in the first direction; and an external electrode disposed on the outer side of the body, and the body may include: 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, wherein the internal electrodes in the first outer region and the internal electrodes in the second outer region are thinner than the internal electrodes in the inner region, and the dielectric layers in the first outer region and the second outer region may be thicker than the dielectric layers in 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 can 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 can be greater than 1 and less than or equal to 3.

[0008] The first outer region may include a first inner electrode, a second inner electrode facing the first inner electrode, and a first dielectric layer between the first inner electrode and the second inner electrode, wherein the first inner electrode is the inner electrode closest to the first surface among the plurality of inner electrodes, and the first dielectric layer may be thicker than the dielectric layer in the inner region.

[0009] The second outer region may include a third inner electrode, a fourth inner electrode facing the third inner electrode, and a second dielectric layer between the third inner electrode and the fourth inner electrode, wherein the third inner electrode is the inner electrode closest to the second surface among the plurality of inner electrodes, and the second dielectric layer may be thicker than the dielectric layer in the inner region.

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

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

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

[0013] The main body may further include: a first covering layer disposed on the outer surface of the first outer region in the first direction; and a second covering layer disposed on the outer surface of the second outer region in the first direction.

[0014] The multilayer ceramic capacitor may further include: a plating layer covering the outer electrode.

[0015] The coating 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).

[0017] According to the embodiment of the multilayer ceramic capacitor, the thickness of the dielectric layer in the outer region of the body in the stacking direction can be set to be greater than the thickness of the dielectric layer in the inner region of the body in the stacking direction, thereby preventing crack formation and electrical breakdown. Attached Figure Description

[0018] Figure 1 This is a schematic perspective view of a multilayer ceramic capacitor according to an embodiment.

[0019] Figure 2 It is along Figure 1 The cross-sectional view taken from line I-I'.

[0020] Figure 3 It is along Figure 1 The cross-sectional view taken from line II-II'.

[0021] Figure 4 It is shown Figure 2A magnified view of region A.

[0022] Figure 5 It is shown Figure 2 A magnified view of region B.

[0023] Figure 6 It is shown Figure 2 A magnified view of region C.

[0024] <Explanation of reference numerals in the attached drawings> 1000: Multilayer ceramic capacitor 110: Main Body 120: First external electrode 130: Second external electrode 140, 140a, 140b, 140c: Dielectric layers 143: First Covering Layer 145: Second Covering Layer 150, 150a, 150b, 150c: First internal electrode 160, 160a, 160b, 160c: Second internal electrode 180: First coating 190: Second coating 181, 191: First floor 183, 193: Second floor 185, 195: Third floor. Detailed Implementation

[0025] In the following, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, enabling those skilled in the art to readily implement them. The drawings and description are to be regarded as illustrative in nature, not restrictive. Throughout the specification, the same reference numerals designate the same elements. Furthermore, in the drawings, some constituent elements may be exaggerated, omitted, or shown schematically, and the dimensions of each constituent element do not perfectly reflect the actual dimensions.

[0026] The accompanying drawings are provided to facilitate understanding of the embodiments disclosed in this specification. The technical concepts disclosed in this specification are not limited to the drawings, and it will be understood that this disclosure includes all variations, equivalents, and alternatives included within the technical concepts and scope of this disclosure.

[0027] Ordinal terms such as "first" and "second" are used to describe various constituent elements, but these constituent elements are not limited by the terms. The terms are only used to distinguish one constituent element from other constituent elements.

[0028] Furthermore, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it may be directly on said other element, or there may be other elements in between. In contrast, when an element is referred to as being "directly on" another element, there are no other elements in between. Additionally, when an element is referred to as being "on" a reference portion, the element is located above or below the reference portion, and does not necessarily mean that the element is located above or below the reference portion in a direction opposite to the direction of gravity.

[0029] It will be understood that, in this application, the terms “comprising” and “having” are intended to specify the presence of the features, quantities, steps, operations, constituent elements, and components described herein, or combinations thereof, and do not preclude the presence or addition of one or more other features, quantities, steps, operations, constituent elements, components, or combinations thereof. Therefore, unless expressly stated otherwise, the words “comprising” and variations such as “including” or “containing” will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.

[0030] In addition, throughout the instruction manual, when "on a plane" is mentioned, it means the target part is viewed from above; when "on a cross section" is mentioned, it means the cross section obtained by vertically cutting the target part is viewed from the side.

[0031] Furthermore, throughout the specification, when the term "connection" is used, it not only means that two or more components are directly connected, but also that two or more components are indirectly connected through other components, physically connected, electrically connected, or that even if two or more components are called by different names according to their location or function, the two or more components are a single unit.

[0032] Figure 1 This is a schematic perspective view of a multilayer ceramic capacitor according to an embodiment. Figure 2 It is along Figure 1 The cross-sectional view taken by line I-I', and Figure 3 It is along Figure 1 The cross-sectional view taken from line II-II'.

[0033] Reference Figure 1 , Figure 2 and Figure 3 According to this embodiment, the multilayer ceramic capacitor 1000 includes a body 110, a first external electrode 120 and a second external electrode 130. The body 110 includes a plurality of dielectric layers 140, a plurality of first internal electrodes 150 and a plurality of second internal electrodes 160.

[0034] First, in order to clearly describe this embodiment, the directions are defined as follows: The L-axis, W-axis and T-axis shown in the figure represent axes that indicate the length direction, width direction and thickness direction of the multilayer ceramic capacitor 1000, respectively.

[0035] The thickness direction (T-axis direction) can be a direction perpendicular to the wide surface (main surface) of the sheet-like constituent element. For example, the thickness direction (T-axis direction) can be used as the same concept as the stacking direction of dielectric layer 140.

[0036] The length direction (L-axis direction) can be a direction parallel to the wide surface (main surface) of the sheet-like constituent element, and can be a direction intersecting (e.g., orthogonal) the thickness direction (T-axis direction). For example, the length direction (L-axis direction) can be the direction in which the first external electrode 120 and the second external electrode 130 face each other.

[0037] The width direction (W-axis direction) can be a direction parallel to the wide surface (main surface) of the sheet-like component, and can be a direction that intersects (e.g., orthogonal) both the thickness direction (T-axis direction) and the length direction (L-axis direction).

[0038] The body 110 may have a generally hexahedral shape, but this embodiment is not limited to this. Due to shrinkage during sintering, although the body 110 is not a perfect hexahedral shape, it may have a substantially hexahedral shape. For example, the body 110 may have a substantially cuboid shape (with rounded edges or vertices).

[0039] In this embodiment, for ease of explanation, the surfaces that are opposite to each other in the length direction (L-axis direction) are defined as the first surface S1 and the second surface S2, and the surfaces that are opposite to each other in the width direction (W-axis direction) and connect the first surface S1 and the second surface S2 are defined as the third surface S3 and the fourth surface S4, and the surfaces that are opposite to each other in the thickness direction (T-axis direction) and connect the first surface S1 and the second surface S2 are defined as the fifth surface S5 and the sixth surface S6.

[0040] Therefore, the first direction along which the first surface S1 and the second surface S2 are opposite to each other can be the length direction (L-axis direction), and the second and third directions perpendicular to the first direction and perpendicular to each other can be the thickness direction (T-axis direction) and the width direction (W-axis direction), or they can be the width direction (W-axis direction) and the thickness direction (T-axis direction), respectively.

[0041] In optical micrographs or scanning electron micrographs of cross-sections taken at the center of the main body 110 in the width direction (W-axis direction) and in the length direction (L-axis direction) and thickness direction (T-axis direction), the length of the main body 110 may refer to the maximum value of the lengths of multiple line segments, each of which connects to the two outermost boundary lines of the main body 110 shown in the cross-sectional photograph in the length direction (L-axis direction) and is parallel to the length direction (L-axis direction). Alternatively, the length of the main body 110 may refer to the minimum value of the lengths of multiple line segments, each of which connects to the two outermost boundary lines of the main body 110 shown in the cross-sectional photograph in the length direction (L-axis direction) and is parallel to the length direction (L-axis direction). Alternatively, the length of the body 110 may refer to the arithmetic average of the lengths of at least two of a plurality of line segments, each of which connects the two outermost boundary lines of the body 110 shown in the cross-sectional photograph above that are opposite each other in the length direction (L-axis direction) and are parallel to the length direction (L-axis direction).

[0042] In optical microscopy or scanning electron microscopy (SEM) images of cross-sections of the main body 110 at its center in the width direction (W-axis direction) and along its length direction (L-axis direction) and thickness direction (T-axis direction), the thickness of the main body 110 may refer to the maximum value of the lengths of multiple line segments, each of which connects to the two outermost boundary lines of the main body 110 shown in the cross-sectional image in the thickness direction (T-axis direction) and is parallel to the thickness direction (T-axis direction). Alternatively, the thickness of the main body 110 may refer to the minimum value of the lengths of multiple line segments, each of which connects to the two outermost boundary lines of the main body 110 shown in the cross-sectional image in the thickness direction (T-axis direction) and is parallel to the thickness direction (T-axis direction). Optionally, the thickness of the body 110 may refer to the arithmetic average of the lengths of at least two of the multiple line segments, each of which connects the two outermost boundary lines of the body 110 shown in the cross-sectional photograph above that are opposite each other in the thickness direction (T-axis direction) and is parallel to the thickness direction (T-axis direction).

[0043] In optical microscope or scanning electron microscope (SEM) images of cross-sections of the main body 110 at its center in the thickness direction (T-axis direction) and along its length direction (L-axis direction) and width direction (W-axis direction), the width of the main body 110 may refer to the maximum value of the lengths of multiple line segments, each of which connects to the two outermost boundary lines of the main body 110 shown in the cross-sectional image in the width direction (W-axis direction) and is parallel to the width direction (W-axis direction). Alternatively, the width of the main body 110 may refer to the minimum value of the lengths of multiple line segments, each of which connects to the two outermost boundary lines of the main body 110 shown in the cross-sectional image in the width direction (W-axis direction) and is parallel to the width direction (W-axis direction). Optionally, the width of the body 110 may refer to the arithmetic average of the lengths of at least two of a plurality of line segments, each of which connects the two outermost boundary lines of the body 110 shown in the cross-sectional photograph above that are opposite each other in the width direction (W-axis direction) and are parallel to the width direction (W-axis direction).

[0044] The body 110 may include multiple dielectric layers 140 stacked in the thickness direction (T-axis direction). The boundaries between the dielectric layers 140 may be unclear. For example, the boundaries between the dielectric layers 140 may be very unclear, making them difficult to see without the use of a scanning electron microscope (SEM), and the multiple dielectric layers 140 may appear as a single structure.

[0045] The first inner electrode 150 and the second inner electrode 160 may be stacked alternately, with a dielectric layer 140 situated between the first inner electrode 150 and the second inner electrode 160. This stacking structure may be repeated within the body 110, and the inner electrode closest to the fifth surface S5 of the body 110 may be either the first inner electrode 150 or the second inner electrode 160. Similarly, the inner electrode closest to the sixth surface S6 of the body 110 may be either the first inner electrode 150 or the second inner electrode 160.

[0046] The first inner electrode 150 and the second inner electrode 160 have different polarities and can be electrically insulated from each other by a dielectric layer 140 disposed therebetween.

[0047] The first inner electrode 150 and the second inner electrode 160 can be formed on the surface of the dielectric layer 140 by printing using a conductive paste containing metal. For example, the inner electrodes can be formed on the surface of the dielectric layer by screen printing or gravure printing using a conductive paste containing nickel (Ni) or a nickel (Ni) alloy. However, this embodiment is not limited to this.

[0048] When a voltage is applied between 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 electrically connected to the first external electrode 120 and the second internal electrode 160 electrically connected to the second external electrode 130. The capacitance of the multilayer ceramic capacitor 1000 is proportional to the overlap area of ​​the first internal electrode 150 and the second internal electrode 160 in the thickness direction (T-axis direction).

[0049] In other words, the multilayer ceramic capacitor 1000 may include an effective region and an edge region. The effective region may refer to the area where the first inner electrode 150 and the second inner electrode 160 overlap along the thickness direction (T-axis direction), and the edge region may refer to the area between the effective region and the first surface S1 of the body 110 and the area between the effective region and the second surface S2 of the body 110. In addition, the areas between the effective region and the third surface S3 of the body 110 and the areas between the effective region and the fourth surface S4 of the body 110 may also be referred to as edge regions.

[0050] A first cover layer 143 and a second cover layer 145 may be provided on the outer side of the effective area in the thickness direction (T-axis direction).

[0051] The first cover layer 143 is disposed between the fifth surface S5 of the main body 110 and the inner electrode closest to the fifth surface S5. The second cover layer 145 is disposed between the sixth surface S6 of the main body 110 and the inner electrode closest to the sixth surface S6.

[0052] In other words, inside the body 110, a first cover layer 143 may be disposed on the uppermost inner electrode, and a second cover layer 145 may be disposed below the lowermost inner electrode. The first cover layer 143 and the second cover layer 145 may have the same composition as the dielectric layer 140. The first cover layer 143 and the second cover layer 145 may be formed by stacking one or more dielectric layers on the outer surfaces of the uppermost and lowermost inner electrodes, respectively. Alternatively, the first cover layer 143 and the second cover layer 145 may have a different composition than the dielectric layer 140.

[0053] The first cover layer 143 and the second cover layer 145 can be used to prevent the first inner electrode 150 and the second inner electrode 160 from being damaged by physical or chemical stress.

[0054] The dielectric layer 140 may comprise a ceramic material having a high dielectric constant. For example, the ceramic material may comprise a dielectric ceramic, which includes at least one selected from the group consisting of BaTiO3, CaTiO3, SrTiO3, and CaZrO3. Furthermore, in addition to the ceramic material, the dielectric layer may also comprise auxiliary components, which include at least one selected from the group consisting of manganese (Mn) compounds, iron (Fe) compounds, chromium (Cr) compounds, cobalt (Co) compounds, and nickel (Ni) compounds. For example, the dielectric layer may comprise a ceramic material having a high dielectric constant. 1-x Ca x TiO3 (where 0 < x < 1), Ba(Ti 1-y Ca y )O3 (where, 0<y<1), (Ba 1-x Ca x (Ti) 1-y Zr y O3 (where 0 < x < 1 and 0 < y < 1) and Ba(Ti) 1-y Zr y It is selected from the group consisting of O3 (where 0 < y < 1) and others (i.e., BaTiO3 doped with calcium (Ca), zirconium (Zr) and others), but this disclosure is not limited thereto.

[0055] In addition, dielectric layer 140 may also contain one or more of ceramic additives, organic solvents, plasticizers, binders, and dispersants. Examples of ceramic additives may include transition metal oxides or transition metal carbides, rare earth elements, magnesium (Mg), aluminum (Al), etc.

[0056] The first external electrode 120 and the second external electrode 130 are disposed on the outer side of the main body 110.

[0057] The first external electrode 120 may be disposed on the first surface S1 of the body 110 and extend to the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6. The second external electrode 130 may be disposed on the second surface S2 of the body 110 and extend to the third surface S3, the fourth surface S4, the fifth surface S5, and the 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 the sixth surface S6.

[0058] The first external electrode 120 may include a first contact portion 121, a first strip portion 123, and a first edge portion 125.

[0059] The first contact portion 121 may be the portion that covers the first surface S1 of the main body 110 and contacts the plurality of first internal electrodes 150 for electrical connection thereto.

[0060] In other embodiments, the first contact portion 121 may cover a portion of the first surface S1 of the body 110.

[0061] The first strip 123 extends from the first contact portion 121 to cover 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 strip 123 can help to more securely fix the first external electrode 120 to the body 110.

[0062] The first edge portion 125 may be the portion connecting the first contact portion 121 and the first strip portion 123.

[0063] The second external electrode 130 may include a second contact portion 131, a second strip portion 133, and a second edge portion 135.

[0064] The second contact portion 131 may be the portion that covers the second surface S2 of the main body 110 and contacts the plurality of second internal electrodes 160 for electrical connection thereto.

[0065] In other embodiments, the second contact portion 131 may cover a portion of the second surface S2 of the body 110.

[0066] The second strip 133 extends from the second contact portion 131 to cover 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 strip 133 can help to more firmly fix the second external electrode 130 to the body 110.

[0067] The second edge portion 135 may be the portion connecting the second contact portion 131 and the second strip portion 133.

[0068] As seen in optical microscope or scanning electron microscope (SEM) photographs of the cross-section of the multilayer ceramic capacitor 1000 at its center in the width direction (W-axis direction) along the length direction (L-axis direction) and thickness direction (T-axis direction), the first contact portion 121 and the second contact portion 131 in the multilayer ceramic capacitor 1000 shown in the photographs may have a shape that is substantially parallel to the thickness direction (T-axis direction), the first strip portion 123 and the second strip portion 133 may have a shape that is substantially parallel to the length direction (L-axis direction), and the first edge portion 125 and the second edge portion 135 may have a curved shape. The aforementioned curved shape may be a curved shape in which the tangent changes from a direction parallel to the thickness direction (T-axis direction) to a direction parallel to the length direction (L-axis direction) (or vice versa) (i.e., the inclination angle of the tangent changes from π / 2 to 0 (or vice versa)).

[0069] The first external electrode 120 and the second external electrode 130 may include a conductive material, which includes, but is not limited to, at least one selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), chromium (Cr), titanium (Ti) and alloys thereof.

[0070] As another example, the first external electrode 120 and the second external electrode 130 may comprise metal and glass. The metal may comprise at least one selected from the group consisting of conductive metals, such as copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), and alloys thereof. The glass component included in the external electrodes may comprise a composition containing oxides. The glass component may comprise at least one selected from the group consisting of, for example, silicon oxides, boron oxides, aluminum oxides, transition metal oxides, alkali metal oxides, alkaline earth metal oxides, and combinations thereof. Here, transition metals may comprise at least one selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), and alkali metals may comprise at least one selected from the group consisting of lithium (Li), sodium (Na), and potassium (K), and alkaline earth metals may be selected from magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). There are no particular limitations on the methods for forming these external electrodes. For example, external electrodes can be formed by immersing the substrate in a conductive paste containing metal and glass, or by printing the conductive paste onto the surface of the substrate using screen printing, gravure printing, or similar methods. Alternatively, various methods can be used to form external electrodes, such as applying conductive paste to the surface of the substrate or transferring a dry film made from dried conductive paste onto the substrate.

[0071] In addition, 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.

[0072] Both of the first plating layer 180 and the second plating layer 190 may include 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 181 may contain nickel (Ni), the second layer 183 may contain copper (Cu), and the third layer 185 may contain tin (Sn); however, this embodiment is not limited thereto.

[0073] 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); however, this embodiment is not limited thereto.

[0074] Figure 4 It is shown Figure 2 A magnified view of region A. Figure 5 It is shown Figure 2 A magnified view of region B. Figure 6 It is shown Figure 2 A magnified view of region C.

[0075] Reference Figure 2 , Figure 4 , Figure 5 and Figure 6 In the thickness direction (T-axis direction), the main body 110 may include a first outer region 111, a second outer region 112 and an inner region 113.

[0076] The first outer region 111 may be the region facing the fifth surface S5 of the body 110 and may be in contact with the first covering layer 143.

[0077] The first outer region 111 may include a first inner electrode 150a, a second inner electrode 160a and a dielectric layer 140a (i.e., the first dielectric layer).

[0078] The second inner electrode 160a can be the inner electrode closest to the fifth surface S5 of the main body 110, and the second inner electrode 160a can be the inner electrode facing the first inner electrode 150a. The dielectric layer 140a can be disposed between the first inner electrode 150a and the second inner electrode 160a.

[0079] exist Figure 2 and Figure 3 The diagram shows that the first outer region 111 includes three inner electrodes and three dielectric layers; however, this embodiment is not limited thereto.

[0080] The second outer region 112 may be the region facing the sixth surface S6 of the body 110 and may be in contact with the second cover layer 145.

[0081] The second outer region 112 may include a first inner electrode 150b, a second inner electrode 160b, and a dielectric layer 140b (i.e., the second dielectric layer).

[0082] The first inner electrode 150b may be the inner electrode closest to the sixth surface S6 of the body 110, and the second inner electrode 160b may be the inner electrode facing the first inner electrode 150b. The dielectric layer 140b may be disposed between the first inner electrode 150b and the second inner electrode 160b.

[0083] exist Figure 2 and Figure 3 The second outer region 112 is shown to include three inner electrodes and three dielectric layers; however, this embodiment is not limited thereto.

[0084] The inner region 113 may be the region between the first outer region 111 and the second outer region 112. The inner region 113 may include a first inner electrode 150c, a second inner electrode 160c and a dielectric layer 140c (i.e., a third dielectric layer).

[0085] exist Figure 2 and Figure 3 The diagram shows that the inner region 113 may include four inner electrodes and three dielectric layers; however, this embodiment is not limited thereto.

[0086] 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. Further, although not shown, 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.

[0087] The thickness t1 of the inner electrodes 150a and 160a in the first outer region 111 may be less than the thickness t3 of the inner electrodes 150c and 160c in the inner region 113. The thickness t2 of the inner electrodes 150b and 160b in the second outer region 112 may be less than the thickness t3 of the inner electrodes 150c and 160c in the inner region 113.

[0088] Here, the thickness of the inner electrode can refer to the average thickness of an inner electrode disposed between two dielectric layers. The average thickness of an inner electrode in a 10,000x magnified scanning electron microscope (SEM) image of a cross-section of the body 110 at its center in the width direction (W-axis direction) and along its length direction (L-axis direction) and thickness direction (T-axis direction) can be the arithmetic mean of the thicknesses of the inner electrodes measured from 30 equally spaced points along the length direction (L-axis direction) of the inner electrode in the aforementioned cross-sectional image. These 30 points can be specified in the aforementioned effective area. The average thickness of the inner electrode can be further generalized by measuring the average thickness of each of ten (10) (or fewer) inner electrodes in this way and obtaining the arithmetic mean of the measured values.

[0089] The dielectric layer 140a in the first outer region 111 is thicker than the dielectric layer 140c in the inner region 113.

[0090] The ratio (i.e., d1 / d3) of the thickness d1 of the dielectric layer 140a in the first outer region 111 to the thickness d3 of the dielectric layer 140c in the inner region 113 can be greater than 1 and less than or equal to 3, for example, it can be 3, 2.5, 2 or 1.5. For example, the thickness d3 of the dielectric layer 140c in the inner region 113 can be 0.88 μm, and the thickness d1 of the dielectric layer 140a in the first outer region 111 can be 0.93 μm. As an example, the thickness d3 of the dielectric layer 140c in the inner region 113 can be in the range of 0.85 μm to 0.90 μm, and the thickness d1 of the dielectric layer 140a in the first outer region 111 can be in the range of 0.91 μm to 0.96 μm.

[0091] The dielectric layer 140b in the second outer region 112 may be thicker than the dielectric layer 140c in the inner region 113.

[0092] The thickness ratio (i.e., d2 / d3) of the dielectric layer 140b in the second outer region 112 to the dielectric layer 140c in the inner region 113 can be greater than 1 and less than or equal to 3, for example, it can be 3, 2.5, 2 or 1.5. For example, the thickness d3 of the dielectric layer 140c in the inner region 113 can be 0.88 μm, and the thickness d2 of the dielectric layer 140b in the second outer region 112 can be 0.93 μm. As an example, the thickness d3 of the dielectric layer 140c in the inner region 113 can be in the range of 0.85 μm to 0.90 μm, and the thickness d2 of the dielectric layer 140b in the second outer region 112 can be in the range of 0.91 μm to 0.96 μm. The thickness d3 of the dielectric layer 140c in the inner region 113, the thickness d2 of the dielectric layer 140b in the second outer region 112, and the thickness d1 of the dielectric layer 140a in the first outer region 111 are not limited to these. The thickness d2 of the dielectric layer 140b in the second outer region 112 and the thickness d1 of the dielectric layer 140a in the first outer region 111 may be the same.

[0093] Here, the thickness of the dielectric layer may refer to the average thickness of a dielectric layer disposed between the two inner electrodes. The average thickness of a dielectric layer in a 10,000x magnified scanning electron microscope (SEM) image of a cross-section of the body 110 at its center in the width direction (W-axis direction) and along its length direction (L-axis direction) and thickness direction (T-axis direction) can be the arithmetic mean of the thicknesses of the dielectric layer measured from 30 equally spaced points along the length direction (L-axis direction) in the aforementioned cross-sectional image. These 30 points may be specified in the aforementioned effective area. The average thickness of the dielectric layer can be further generalized by measuring the average thickness of each of ten (10) (or fewer) dielectric layers in this manner and obtaining the arithmetic mean of the measured values.

[0094] Furthermore, the dielectric layer 140a in the first outer region 111 may be thicker than the dielectric layer 140c in the inner region 113, and the thickness t1 of the inner electrodes 150a and 160a in the first outer region 111 may be less than the thickness t3 of the inner electrodes 150c and 160c in the inner region 113. The dielectric layer 140b in the second outer region 112 may be thicker than the dielectric layer 140c in the inner region 113, and the thickness t2 of the inner electrodes 150b and 160b in the second outer region 112 may be less than the thickness t3 of the inner electrodes 150c and 160c in the inner region 113. Specifically, the thickness of the inner electrodes 150a and 160a in the first outer region 111 can be reduced by increasing the thickness of the dielectric layer 140a in the first outer region 111, and the thickness of the inner electrodes 150b and 160b in the second outer region 112 can be reduced by increasing the thickness of the dielectric layer 140b in the second outer region 112. In other words, the increase in the thickness of the dielectric layer and the decrease in the thickness of the inner electrodes can be offset. Thus, the overall thickness of the multilayer ceramic capacitor can be maintained within a certain range.

[0095] Typically, cracks or electrical breakdowns may occur primarily in the dielectric layer closest to the outer surface of the multilayer ceramic capacitor in the thickness direction (T-axis direction). As an example, the thickness of the dielectric layer in each of the first outer region 111 and the second outer region 112 may decrease with increasing distance from the corresponding outer surface. Furthermore, the thicknesses of the multiple dielectric layers in each of the first outer region 111, the second outer region 112, and the inner region 113 may be substantially the same.

[0096] According to this embodiment, since the thickness of the dielectric layer in the first outer region 111, which is closest to the fifth surface S5 of the body 110, and the second outer region 112, which is closest to the sixth surface S6 of the body 110, is greater than the thickness of the dielectric layer in the inner region 113, cracks or electrical breakdowns in 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 has improved reliability.

[0097] [Experimental Example: Insulation Resistance of Multilayer Ceramic Capacitors] Fifty multilayer ceramic capacitors were manufactured for each of the example and comparative examples and then mounted on a substrate. High-temperature load tests were then conducted at 125°C, 1.2 atm, 95% RH, and the applied rated voltage, and failure was determined when the insulation resistance decreased to 10 kΩ or less. The mean time to failure (MTTF) was calculated based on these failure times. The results are summarized in Table 1.

[0098] (Table 1)

[0099] Referring to Table 1, the mean time to failure (MTBF) of the multilayer ceramic capacitor according to the example is 11.83 hours, while the MTBF of the multilayer ceramic capacitor according to the comparative example is 8.2 hours. In other words, the MTBF of the multilayer ceramic capacitor according to the example is longer than that of the multilayer ceramic capacitor according to the comparative example. This appears to be because the dielectric layers in the first and second outer regions are thicker than those in the inner regions, thus preventing cracks or electrical breakdown in the dielectric layers.

[0100] While this disclosure has been described in conjunction with what is now considered to be actual embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. Instead, it is intended to cover various modifications and equivalents included within the spirit and scope of the appended claims.

Claims

1. A multilayer ceramic capacitor, comprising: The body includes a plurality of internal electrodes and a plurality of dielectric layers alternately stacked in a first direction, with each dielectric layer located between adjacent internal electrodes among the plurality of internal electrodes, and the body has a first surface and a second surface opposite to each other in the first direction; as well as The external electrode is disposed on the outer side of the main body. The main body includes: The first outer region faces the first surface; The second outer region faces the second surface; and The inner region, located between the first outer region and the second outer region, The plurality of inner electrodes includes an inner electrode in the first outer region, an inner electrode in the second outer region, and an inner electrode in the inner region. Wherein, the inner electrode in the first outer region and the inner electrode in the second outer region are thinner than the inner electrode in the inner region, and The plurality of dielectric layers include a dielectric layer in the first outer region, a dielectric layer in the second outer region, and a dielectric layer in the inner region. The dielectric layer in the first outer region and the dielectric layer in the second outer region are thicker than the dielectric layer in 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 1 or 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 multilayer ceramic capacitor according to claim 1, wherein: The first outer region includes a first inner electrode, a second inner electrode facing the first inner electrode, and a first dielectric layer between the first inner electrode and the second inner electrode. The first inner electrode is the inner electrode closest to the first surface among the plurality of inner electrodes. The first dielectric layer is thicker than the dielectric layer in the inner region.

5. The multilayer ceramic capacitor according to claim 1 or 4, wherein: The second outer region includes a third inner electrode, a fourth inner electrode facing the third inner electrode, and a second dielectric layer between the third inner electrode and the fourth inner electrode. The third inner electrode is the inner electrode closest to the second surface among the plurality of inner electrodes. The second dielectric layer is thicker than the dielectric layer in the inner region.

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

7. The multilayer ceramic capacitor according to claim 1 or 6, wherein: The number of inner electrodes in the second outer region is less than the number of inner electrodes in the inner region.

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

9. The multilayer ceramic capacitor according to claim 1, wherein: The subject also includes: A first covering layer is disposed on the outer surface of the first outer region in the first direction; and A second covering layer is disposed on the outer surface of the second outer region in the first direction.

10. The multilayer ceramic capacitor according to claim 1, wherein the multilayer ceramic capacitor further comprises: A coating is applied to cover the outer electrode.

11. The multilayer ceramic capacitor according to claim 10, wherein: The coating includes: The first layer covers the outer electrode; The second layer covers the first layer; and The third layer covers the second layer.

12. The multilayer ceramic capacitor according to claim 11, wherein: The first layer contains nickel. The second layer contains copper, and The third layer contains tin.

13. The multilayer ceramic capacitor according to claim 2, wherein, The thickness of the dielectric layer in the inner region is 0.88 μm, and the thickness of the dielectric layer in the first outer region is 0.93 μm.

14. The multilayer ceramic capacitor according to claim 3, wherein, The thickness of the dielectric layer in the inner region is 0.88 μm, and the thickness of the dielectric layer in the second outer region is 0.93 μm.

15. The multilayer ceramic capacitor according to claim 1, wherein, The thickness of the dielectric layer in the inner region is in the range of 0.85 μm to 0.90 μm, and the thickness of the dielectric layer in the first outer region or the second outer region is in the range of 0.91 μm to 0.96 μm.

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