Multilayer ceramic capacitor
The multilayer ceramic capacitor design addresses the trade-off between ESR and bending strength by using thicker conductive resin layers on the mounting surface, enhancing flexibility and capacitance retention.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- SAMSUNG ELECTRO MECHANICS CO LTD
- Filing Date
- 2025-06-20
- Publication Date
- 2026-06-01
Smart Images
Figure 2026089645000001_ABST
Abstract
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] For example, multilayer ceramic capacitors can be used as chip-type capacitors mounted on the substrates of various electronic products such as liquid crystal displays (LCDs), plasma display panels (PDPs), organic light-emitting diodes (OLEDs), computers, personal portable devices, and smartphones, playing a role in charging or discharging electricity.
[0004] Multilayer ceramic capacitors can include internal electrodes located inside the body and external electrodes located outside the body but connected to the internal electrodes. The external electrodes may include an electrode layer and a conductive resin layer covering it, and an external electrode structure is required that can lower the equivalent series resistance (ESR) while increasing bending strength. [Overview of the project] [Problems that the invention aims to solve]
[0005] One embodiment of the present invention aims to provide a multilayer ceramic capacitor that can lower its equivalent series resistance while increasing its bending strength.
[0006] However, the problems that the embodiments of the present invention aim to solve are not limited to those described above, and can be broadly expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]
[0007] A multilayer ceramic capacitor according to one embodiment of the present invention includes a body having a plurality of internal electrodes stacked in a first direction with a dielectric layer interposed between them, a first surface and a second surface arranged on opposite sides in the first direction, and an external electrode disposed outside the body and connected to the plurality of internal electrodes, the external electrode including a connection portion connected to the plurality of internal electrodes in a second direction intersecting the first direction, a first band portion connected to the connection portion and covering a part of the first surface, a second band portion connected to the connection portion and covering a part of the second surface, a first conductive resin layer covering the first band portion and exposing the connection portion, and a second conductive resin layer covering the second band portion and exposing the connection portion, wherein the thickness of the second conductive resin layer may be greater than the thickness of the first conductive resin layer.
[0008] The average thickness of the second conductive resin layer may be at least twice the average thickness of the first conductive resin layer.
[0009] The first conductive resin layer may cover a portion of the first band portion, and the second conductive resin layer may cover a portion of the second band portion.
[0010] The first conductive resin layer may cover a portion of the first surface, and the second conductive resin layer may cover a portion of the second surface.
[0011] In the region where the first conductive resin layer covers the first surface, the length of the portion in contact between the first conductive resin layer and the first surface may be greater than the thickness of the first conductive resin layer.
[0012] In the region where the second conductive resin layer covers the second surface, the length of the portion in contact between the second conductive resin layer and the second surface may be greater than the thickness of the second conductive resin layer.
[0013] The outer surface of the first conductive resin layer may include a curved surface, and the outer surface of the second conductive resin layer may also include a curved surface.
[0014] The length of the first conductive resin layer may be greater than the length of the first band portion, and the length of the second conductive resin layer may be greater than the length of the second band portion.
[0015] The length of the first conductive resin layer may be greater than the thickness of the first conductive resin layer, and the length of the second conductive resin layer may be greater than the thickness of the second conductive resin layer.
[0016] If the length of the body is Lc, the thickness of the first conductive resin layer is t1, and the thickness of the second conductive resin layer is t2, then Lc / 500 ≤ t1 <t2≦Lc / 50であってもよい。
[0017] If the length of the body is Lc and the thickness of the connection part is Tz, then Lc / 250 ≤ Tz ≤ Lc / 25 is also acceptable.
[0018] The body includes a third surface and a fourth surface that are arranged on opposite sides of each other in a third direction that intersects the first and second directions simultaneously, and the external electrode further includes a third band portion connected to the connection portion and covering a portion of the third surface, a fourth band portion connected to the connection portion and covering a portion of the fourth surface, a third conductive resin layer covering the third band portion, and a fourth conductive resin layer covering the fourth band portion, wherein the first conductive resin layer, the third conductive resin layer, and the fourth conductive resin layer may have the same average thickness.
[0019] The same average thickness of the first conductive resin layer, the third conductive resin layer, and the fourth conductive resin layer may be smaller than the average thickness of the second conductive resin layer.
[0020] The body includes a third surface and a fourth surface that are arranged on opposite sides in a third direction that intersects the first direction and the second direction at the same time. The external electrode further includes a third band portion that is connected to the connection portion and covers a part of the third surface, a fourth band portion that is connected to the connection portion and covers a part of the fourth surface, a third conductive resin layer that covers the third band portion, and a fourth conductive resin layer that covers the fourth band portion. The average thickness of the first conductive resin layer, the average thickness of the third conductive resin layer, and the average thickness of the fourth conductive resin layer may all be smaller than the average thickness of the second conductive resin layer.
[0021] The body includes a third surface and a fourth surface that are arranged on opposite sides in a third direction that intersects the first direction and the second direction at the same time. The external electrode further includes a third band portion that is connected to the connection portion and covers a part of the third surface, a fourth band portion that is connected to the connection portion and covers a part of the fourth surface, a third conductive resin layer that covers the third band portion, and a fourth conductive resin layer that covers the fourth band portion. The average thickness of the first conductive resin layer is the same as the average thickness of the fourth conductive resin layer, and may be smaller than the average thickness of the second conductive resin layer and the average thickness of the third conductive resin layer.
[0022] The average thickness of the third conductive resin layer may be smaller than the average thickness of the second conductive resin layer.
[0023] The body includes a third surface and a fourth surface that are arranged on opposite sides in a third direction that intersects the first direction and the second direction at the same time. The external electrode further includes a third band portion that is connected to the connection portion and covers a part of the third surface, a fourth band portion that is connected to the connection portion and covers a part of the fourth surface, a third conductive resin layer that covers the third band portion, and a fourth conductive resin layer that covers the fourth band portion. The average thickness of the first conductive resin layer is the same as the average thickness of the third conductive resin layer, and may be smaller than the average thickness of the second conductive resin layer and the average thickness of the fourth conductive resin layer.
[0024] The average thickness of the fourth conductive resin layer may be less than the average thickness of the second conductive resin layer.
[0025] The first conductive resin layer and the second conductive resin layer may each contain a metal and a resin.
[0026] The multilayer ceramic capacitor may further include a plating layer covering the external electrodes.
[0027] According to an embodiment of the present invention, the multilayer ceramic capacitor can be made more flexible and its equivalent series resistance less flexible by further increasing the thickness of the conductive resin layer on the mounting surface side. [Brief explanation of the drawing]
[0028] [Figure 1] Figure 1 is a schematic perspective view showing a multilayer ceramic capacitor according to one embodiment. [Figure 2] Figure 2 is a separated perspective view schematically showing the layered structure of the internal electrodes in the multilayer ceramic capacitor shown in Figure 1. [Figure 3] Figure 3 is a schematic plan view showing the first internal electrode of the multilayer ceramic capacitor shown in Figure 1. [Figure 4] Figure 4 is a schematic plan view showing the second internal electrode of the multilayer ceramic capacitor shown in Figure 1. [Figure 5] Figure 5 is a cross-sectional view taken along the line I-I' in Figure 1. [Figure 6] Figure 6 is a cross-sectional view taken along the line II-II' in Figure 1. [Figure 7] Figure 7 is a cross-sectional view taken along the line III-III' in Figure 1. [Figure 8] Figure 8 is a schematic partial cross-sectional view showing area A in Figure 5. [Figure 9] Figure 9 is a schematic partial cross-sectional view showing area B in Figure 5. [Figure 10] Figure 10 is a graph showing the relative comparison of stress changes due to increasing thickness of the conductive resin layer. [Figure 11] Figure 11 is a schematic cross-sectional view showing the multilayer ceramic capacitor shown in Figure 1 mounted on a circuit board. [Modes for carrying out the invention]
[0029] Embodiments of the present invention will be described in detail below with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. In the drawings, unnecessary parts have been omitted in order to clearly illustrate the present invention, and the same or similar components are denoted by the same reference numerals throughout the specification. In addition, some components in the attached drawings are exaggerated, omitted, or shown schematically, and the size of each component does not fully reflect its actual size.
[0030] The accompanying drawings are provided solely to facilitate understanding of the embodiments disclosed herein, and should not be understood as limiting the technical ideas disclosed herein, and should be understood to include any modifications, equivalents, or substitutions that fall within the concept and scope of the invention.
[0031] Terms including ordinal numbers, such as "first," "second," etc., can be used to describe a variety of components, but the components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.
[0032] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on top of" another part, this includes not only the case where it is "directly above" the other part, but also the case where the other part is in between. Conversely, when we say that one part is "directly above" another part, it means that there is no other part in between. Also, being "on top of" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" in the opposite direction of gravity.
[0033] 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 be understood not 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.
[0034] 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 a cross-section obtained by cutting the part in question perpendicularly, as seen from the side.
[0035] 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.
[0036] Figure 1 is a schematic perspective view showing a multilayer ceramic capacitor according to one embodiment.
[0037] Referring to Figure 1, the multilayer ceramic capacitor 1000 according to an embodiment of the present invention includes a body 110, a first external electrode 200, and a second external electrode 300.
[0038] First, to clearly explain the embodiments of the present invention, directions are defined as follows: the T-axis, L-axis, and W-axis shown in the drawing represent the first, second, and third directions of the multilayer ceramic capacitor 1000, respectively.
[0039] The first direction (T-axis direction) may be perpendicular to the broad surface (main surface) of the sheet-shaped component. For example, the first direction (T-axis direction) can be used with the same concept as the direction in which the dielectric layer 140 is stacked. Hereinafter, the first direction will be referred to as the "thickness direction" when necessary.
[0040] The second direction (L-axis direction) may be a direction parallel to the broad surface (main surface) of the sheet-shaped component, intersecting (or perpendicular to) the thickness direction (T-axis direction). For example, the second direction (L-axis direction) may be the direction in which the first external electrode 200 and the second external electrode 300 face each other. Hereinafter, the second direction will be referred to as the "length direction" when necessary.
[0041] The third direction (W-axis direction) is a direction parallel to the wide surface (main surface) of the sheet-shaped component, and may intersect (or be perpendicular to) the first direction (T-axis direction) and the second direction (L-axis direction) simultaneously. Hereafter, the third direction will be referred to as the "width direction" when necessary.
[0042] The body 110 may be approximately hexahedral in shape, but the embodiments of the present invention are not limited thereto. 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.
[0043] In embodiments of the present invention, for the sake of explanation, the surfaces of the body 110 that face each other in the thickness direction (T-axis direction) are defined as the first surface S1 and the second surface S2, the surfaces of the body 110 that face each other in the length direction (L-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 of the body 110 that face each other in the width direction (W-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.
[0044] Therefore, the first direction in which the first surface S1 and the second surface S2 face each other may be the thickness direction (T-axis direction), and the second and third directions, which are perpendicular to the first direction and perpendicular to each other, may be the length direction (L-axis direction) and the width direction (W-axis direction) or the width direction (W-axis direction) and the length direction (L-axis direction), respectively.
[0045] The length of body 110 may represent the maximum length of a plurality of line segments parallel to the length direction (L-axis direction), obtained by connecting the two outermost boundary lines of body 110 facing each other in the length direction (L-axis direction) as shown in the aforementioned cross-sectional photograph of body 110 in the length direction (L-axis direction) - thickness direction (T-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the cross-sectional photograph of body 110 in the length direction (L-axis direction). On the other hand, the length of body 110 may represent the minimum length of a plurality of line segments parallel to the length direction (L-axis direction), obtained by connecting the two outermost boundary lines of body 110 facing each other in the length direction (L-axis direction), as shown in the aforementioned cross-sectional 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), obtained by connecting the two outermost boundary lines of body 110 facing each other in the length direction (L-axis direction), as shown in the aforementioned cross-sectional photograph.
[0046] The thickness of body 110 may represent the maximum length of a plurality of line segments parallel to the thickness direction (T-axis direction), obtained by connecting the two outermost boundary lines of body 110 that are opposite each other in the thickness direction (T-axis direction) as shown in the aforementioned cross-sectional photograph of body 110 in the length direction (L-axis direction) - thickness direction (T-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the cross-sectional photograph of body 110 in the width direction (W-axis direction). 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), obtained 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-sectional 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), obtained 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-sectional photograph.
[0047] The width of body 110 may represent the maximum length of a plurality of line segments parallel to the width direction (W-axis direction), obtained by connecting the two outermost boundary lines of body 110 facing each other in the width direction (W-axis direction) as shown in the aforementioned cross-sectional photograph of body 110 in the length direction (L-axis direction) - width direction (W-axis direction), based on an optical microscope or scanning electron microscope (SEM) photograph of the cross-section of body 110 in the length direction (L-axis direction) - width direction (W-axis direction), as shown in the aforementioned cross-sectional 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), obtained by connecting the two outermost boundary lines of body 110 facing each other in the width direction (W-axis direction), as shown in the aforementioned cross-sectional 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), obtained by connecting the two outermost boundary lines of body 110 facing each other in the width direction (W-axis direction), as shown in the aforementioned cross-sectional photograph.
[0048] FIG. 2 is a separated perspective view schematically showing the laminated structure of the internal electrodes in the multilayer ceramic capacitor of FIG. 1, FIG. 3 is a plan view schematically showing the first internal electrode of the multilayer ceramic capacitor of FIG. 1, and FIG. 4 is a plan view schematically showing the second internal electrode of the multilayer ceramic capacitor of FIG. 1. FIG. 5 is a cross-sectional view taken along the line I-I' of FIG. 1, FIG. 6 is a cross-sectional view taken along the line II-II' of FIG. 1, and FIG. 7 is a cross-sectional view taken along the line III-III' of FIG. 1.
[0049] Referring to FIGS. 2, 3, 4, 5, 6, and 7, the body 110 can include a plurality of dielectric layers 140, a first internal electrode 150, and a second internal electrode 160.
[0050] The plurality of dielectric layers 140 are laminated in the thickness direction (T-axis direction) of the body 110. The boundaries between the dielectric layers 140 may be unclear. For example, the boundaries between the dielectric layers 140 are difficult to confirm without using a scanning electron microscope (SEM), and the plurality of dielectric layers 140 may appear as an integral structure.
[0051] The dielectric layer 140 can include a 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 Zry ) There are O3 (0 < y < 1) etc., but the present invention is not limited thereto.
[0052] The dielectric layer 140 can further contain one or more of a ceramic additive, an organic solvent, a plasticizer, a binder, and a dispersant. The ceramic additive may be, for example, a transition metal oxide or carbide, a rare earth element, magnesium (Mg) or aluminum (Al), etc.
[0053] The first internal electrode 150 and the second internal electrode 160 may be alternately laminated with the dielectric layer 140 interposed therebetween. Such a laminated structure may be repeated within the body 110, and the internal electrode closest to the first surface S1 of the body 110 may be the first internal electrode 150 or the second internal electrode 160, and the internal electrode closest to the second surface S2 may be the first internal electrode 150 or the second internal electrode 160.
[0054] The first internal electrode 150 and the second internal electrode 160 have different polarities from each other, but can be electrically insulated from each other by the dielectric layer 140 disposed therebetween.
[0055] The first internal electrode 150 and the second internal electrode 160 may be arranged so as to be offset from each other in the length direction (L-axis direction) with the dielectric layer 140 interposed therebetween. One end portion of the first internal electrode 150 can be exposed through the third surface S3 of the body 110, and one end portion of the second internal electrode 160 can be exposed through the fourth surface S4 of the body 110. The end portion of the first internal electrode 150 exposed from the third surface S3 of the body 110 may be connected to the first external electrode 200. The end portion of the second internal electrode 160 exposed from the fourth surface S4 of the body 110 may be connected to the second external electrode 300.
[0056] 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, the embodiments of the present invention are not limited thereto.
[0057] When a voltage is applied to the first external electrode 200 and the second external electrode 300, 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 200, and the second internal electrode 160, which is electrically connected to the second external electrode 300. 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).
[0058] Referring to Figures 5 and 7, a first cover layer 143 and a second cover layer 145 may be arranged on the outermost part of the body 110 in the thickness direction (T-axis direction).
[0059] The first cover layer 143 is positioned between the first surface S1 of the body 110 and the internal electrode closest to it. The second cover layer 145 is positioned between the second surface S2 of the body 110 and the internal electrode closest to it.
[0060] In other words, the first cover layer 143 may be placed on top of the uppermost internal electrode within the body 110, and the second cover layer 145 may be placed on top of the lowermost internal 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 can be formed by laminating one or more dielectric layers on the outer surface of the uppermost internal electrode and the outer surface of the lowermost internal electrode, respectively. On the other hand, the first cover layer 143 and the second cover layer 145 may have a different composition from the dielectric layer 140.
[0061] 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.
[0062] The first external electrode 200 and the second external electrode 300 are positioned outside the body 110.
[0063] The first external electrode 200 is positioned on the third surface S3 of the body 110 and can extend to the first surface S1, the second surface S2, the fifth surface S5, and the sixth surface S6. The second external electrode 300 is positioned on the fourth surface S4 of the body 110 and can extend to the first surface S1, the second surface S2, the fifth surface S5, and the sixth surface S6.
[0064] The first external electrode 200 may include a first electrode layer 210, a first conductive resin layer 220, a second conductive resin layer 230, a third conductive resin layer 240, and a fourth conductive resin layer 250.
[0065] The first electrode layer 210 contains a metal. The first electrode layer 210 may include one or more of the following: silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and alloys thereof.
[0066] The first electrode layer 210 may include a first connection portion 211, a first band portion 212, a second band portion 213, a third band portion 214, and a fourth band portion 215.
[0067] The first connection portion 211 covers the third surface S3 of the body 110 and is connected to the exposed ends of the multiple first internal electrodes 150, thereby being electrically coupled.
[0068] The first band portion 212 extends from the first connecting portion 211 and covers a part of the first surface S1 of the body 110, and the second band portion 213 extends from the first connecting portion 211 and covers a part of the second surface S2 of the body 110.
[0069] The third band portion 214 extends from the first connecting portion 211 and covers a part of the fifth surface S5 of the body 110, and the fourth band portion 215 extends from the first connecting portion 211 and covers a part of the sixth surface S6 of the body 110.
[0070] The first conductive resin layer 220 covers the first band portion 212, exposing the first connection portion 211. In other words, the first conductive resin layer 220 is not placed on the first connection portion 211.
[0071] For example, the first conductive resin layer 220 can cover a part or all of the first band portion 212. Alternatively, the first conductive resin layer 220 can cover a part of the first surface S1 of the body 110.
[0072] The outer surface of the first conductive resin layer 220 may include a curved surface.
[0073] Referring to Figure 8, the length L1 of the first conductive resin layer 220 may be greater than the length Lb1 of the first band portion 212. The length L1 of the first conductive resin layer 220 may also be greater than its thickness t1.
[0074] Here, the length and thickness of the first conductive resin layer 220 and the length of the first band portion 212 are measured based on optical microscope or scanning electron microscope (SEM) images 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 length of the first conductive resin layer 220 may represent the maximum length of a plurality of line segments parallel to the length direction (L-axis direction) by connecting the two outermost boundary lines of the first conductive resin layer 220 that are opposite to each other in the length direction (L-axis direction) as shown in the aforementioned cross-sectional image. The thickness of the first conductive resin layer 220 may represent the maximum length of a plurality of line segments parallel to the thickness direction (T-axis direction) by connecting the two outermost boundary lines of the first conductive resin layer 220 that are opposite to each other in the thickness direction (T-axis direction) as shown in the aforementioned cross-sectional image. Furthermore, the length of the first band portion 212 may represent the maximum length among multiple line segments parallel to the length direction (L-axis direction) of the first band portion 212, which are formed by connecting the two outermost boundary lines that are opposite each other in the length direction (L-axis direction) of the first band portion 212 as shown in the aforementioned cross-sectional photograph.
[0075] The relationship between the length Lc of the body 110 and the thickness t1 of the first conductive resin layer 220 may be Lc / 500 ≤ t1 ≤ Lc / 50.
[0076] If Lc / 500 > t1, the thickness of the first conductive resin layer may be excessively thin and insufficient to ensure the moisture resistance reliability of the multilayer ceramic capacitor. If t1 > Lc / 50, the first conductive resin layer may be excessively thick compared to the thickness of the multilayer ceramic capacitor, making it difficult to secure sufficient capacitance relative to the size of the multilayer ceramic capacitor.
[0077] The thickness t1 of the first conductive resin layer 220 can be 1 μm or more.
[0078] On the other hand, in the region where the first conductive resin layer 220 covers the first surface S1 of the body 110, the length Ls1 of the first conductive resin layer 220 may be greater than the thickness ts1. In other words, the length Ls1 of the portion in which the first conductive resin layer 220 and the first surface S1 are in contact may be greater than the thickness ts1 of the first conductive resin layer 220 in that region.
[0079] The second conductive resin layer 230 covers the second band portion 213, exposing the first connection portion 211. In other words, the second conductive resin layer 230 is not placed on the first connection portion 211.
[0080] For example, the second conductive resin layer 230 can cover a part or all of the second band portion 213. Alternatively, the second conductive resin layer 230 can cover a part of the second surface S2 of the body 110.
[0081] The outer surface of the second conductive resin layer 230 may include a curved surface.
[0082] Referring to Figure 9, the length L2 of the second conductive resin layer 230 may be greater than the length Lb2 of the second band portion 213. The length L2 of the second conductive resin layer 230 may also be greater than its thickness t2.
[0083] Here, the length and thickness of the second conductive resin layer 230 and the length of the second band portion 213 are measured based on optical microscope or scanning electron microscope (SEM) images 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 specific measurement method is the same as the measurement method for the length and thickness of the first conductive resin layer 220 and the length of the first band portion 212 described above, so a repeated explanation of that method will be omitted.
[0084] The relationship between the length Lc of the body 110 and the thickness t2 of the second conductive resin layer 230 may be Lc / 500 ≤ t2 ≤ Lc / 50.
[0085] If Lc / 500 > t2, the thickness of the second conductive resin layer may be excessively thin and insufficient to ensure the moisture resistance reliability of the multilayer ceramic capacitor. If t2 > Lc / 50, the second conductive resin layer may be excessively thick compared to the thickness of the multilayer ceramic capacitor, making it difficult to secure sufficient capacitance relative to the size of the multilayer ceramic capacitor.
[0086] On the other hand, in the region where the second conductive resin layer 230 covers the second surface S2 of the body 110, the length Ls2 of the second conductive resin layer 230 may be greater than the thickness ts2. In other words, the length Ls2 of the portion in which the second conductive resin layer 230 and the second surface S2 are in contact may be greater than the thickness ts2 of the second conductive resin layer 230 in that region.
[0087] According to an embodiment of the present invention, when the multilayer ceramic capacitor 1000 is mounted on a substrate, the second conductive resin layer 230 is positioned on the mounting surface side.
[0088] Figure 10 is a graph showing the relative comparison of stress changes due to increasing thickness of the conductive resin layer.
[0089] Referring to Figure 10, it can be seen that, compared to existing POR (process of record), the stress decreases as the thickness of the conductive resin layer of the multilayer ceramic capacitor increases. Therefore, according to the embodiment of the present invention, the bending strength characteristics of the multilayer ceramic capacitor can be improved by increasing the thickness of the second conductive resin layer 230 located on the mounting surface side.
[0090] The third conductive resin layer 240 covers the third band portion 214, exposing the first connection portion 211. In other words, the third conductive resin layer 240 is not placed on the first connection portion 211. For example, the third conductive resin layer 240 can cover part or all of the third band portion 214. Also, the third conductive resin layer 240 can cover part of the fifth surface S5 of the body 110.
[0091] The fourth conductive resin layer 250 covers the fourth band portion 215, exposing the first connection portion 211. In other words, the fourth conductive resin layer 250 is not placed on the first connection portion 211. For example, the fourth conductive resin layer 250 can cover part or all of the fourth band portion 215. Also, the fourth conductive resin layer 250 can cover part of the sixth surface S6 of the body 110.
[0092] Referring to Figure 7, the first conductive resin layer 220 has a first average thickness ta1, the second conductive resin layer 230 has a second average thickness ta2, the third conductive resin layer 240 has a third average thickness ta3, and the fourth conductive resin layer 250 has a fourth average thickness ta4.
[0093] The second average thickness ta2 of the second conductive resin layer 230 may be greater than the first average thickness ta1 of the first conductive resin layer 220. For example, the second average thickness ta2 of the second conductive resin layer 230 may be at least twice the first average thickness ta1 of the first conductive resin layer 220.
[0094] In one embodiment of the present invention, the first average thickness ta1, the third average thickness ta3, and the fourth average thickness ta4 may all be smaller than the second average thickness ta2.
[0095] In other embodiments, the first average thickness ta1, the third average thickness ta3, and the fourth average thickness ta4 are the same and may all be smaller than the second average thickness ta2.
[0096] In other embodiments, the first average thickness ta1 and the fourth average thickness ta4 are the same and may both be smaller than the second average thickness ta2 and the third average thickness ta3. Here, the third average thickness ta3 may be smaller than the second average thickness ta2.
[0097] In other embodiments, the first average thickness ta1 and the third average thickness ta3 are the same and may both be smaller than the second average thickness ta2 and the fourth average thickness ta4. Here, the fourth average thickness ta4 may be smaller than the second average thickness ta2.
[0098] Here, the first average thickness ta1, the second average thickness ta2, the third average thickness ta3, and the fourth average thickness ta4 are measured based on an optical microscope or scanning electron microscope (SEM) image of the cross section in the width direction (W-axis direction) - thickness direction (T-axis direction) at the center of the length direction (L direction) of one external electrode of the multilayer ceramic capacitor 1000. The first average thickness ta1 may be the arithmetic mean of the thickness of the first conductive resin layer 220 shown in the aforementioned cross section image, measured at 10 points that are evenly spaced in the width direction (W-axis direction). The aforementioned 10 points may be specified within a range corresponding to 60% of the width Wc of the body 110. For example, referring to Figure 7, the first average thickness ta1 can be obtained by measuring the thickness of the first conductive resin layer 220 at 10 points spaced at the same interval within the range obtained by excluding the range corresponding to 20% of the width Wc of the body 110 on the left and right sides of the body 110, respectively, and then taking the arithmetic mean. The second average thickness ta2 can be obtained using a similar method.
[0099] On the other hand, the third average thickness ta3 may be the arithmetic mean of the thickness of the third conductive resin layer 240 shown in the aforementioned cross-sectional photograph, measured at 10 points spaced equally in the thickness direction (T-axis direction). The aforementioned 10 points may be specified within a range corresponding to 60% of the thickness Tc of the body 110. For example, referring to Figure 7, the third average thickness ta3 can be obtained by measuring the thickness of the second conductive resin layer 230 at 10 points spaced equally apart within the range obtained by excluding the range corresponding to 20% of the thickness Tc of the body 110 on the upper and lower sides of the body 110, respectively, and then taking the arithmetic mean. The fourth average thickness ta4 can be obtained in a similar manner.
[0100] Referring to Figure 6, the body 110 has a length Lc, and the first connecting portion 211 has a thickness Tz.
[0101] The relationship between the length Lc of the body 110 and the thickness Tz of the first connection portion 211 may be Lc / 250 ≤ Tz ≤ Lc / 25.
[0102] If Lc / 250 > Tz, the first connection may be excessively thin and insufficient to ensure the moisture resistance reliability of the multilayer ceramic capacitor. If Tz > Lc / 25, the first connection may be excessively thick compared to the length of the multilayer ceramic capacitor, potentially reducing its bending strength.
[0103] Here, the thickness of the first connection portion 211 is measured based on an optical microscope or scanning electron microscope (SEM) image 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 thickness of the first connection portion 211 may represent the maximum length of a plurality of line segments parallel to the length direction (L-axis direction) that connect the two outermost boundary lines of the first connection portion 211 that are opposite each other in the length direction (L-axis direction) as shown in the aforementioned cross-sectional image.
[0104] The first conductive resin layer 220 may contain a metal and a resin.
[0105] The metal contained in the first conductive resin layer 220 may include, for example, copper (Cu), silver (Ag), nickel (Ni), tin (Sn), or alloys thereof.
[0106] The resin contained in the first conductive resin layer 220 may be a variety of known thermosetting resins, such as epoxy resin, phenolic resin, urethane resin, silicone resin, or polyimide resin.
[0107] After the first electrode layer 210 is formed, a conductive resin composition containing metal powder and a thermosetting resin can be applied onto the first electrode layer 210. Here, the thermosetting resin may be, but is not limited to, bisphenol A resin, glycol epoxy resin, novolac epoxy resin, or derivatives thereof that have a small molecular weight and are liquid at room temperature. For example, the conductive resin composition can be produced by mixing silver (Ag) powder, copper (Cu) powder, silver (Ag) coated copper (Cu) powder, tin (Sn)-based solder powder, and a thermosetting resin, and then dispersing them using a 3-roll mill. The tin (Sn)-based solder powder is tin (Sn), Sn 96.5 Ag 3.0 Cu 0.5 Sn 42 Bi 58 and Sn 72 Bi 28 The present disclosure may include, but is not limited to, at least one of the above. Subsequently, after removing the conductive resin composition on the first connection portion 211, the first conductive resin layer 220 can be formed on the first band portion 212 by curing heat treatment. Therefore, the first connection portion 211 may be arranged on the third surface S3 of the body 110, and the first band portion 212 and the first conductive resin layer 220 may be arranged on the first surface S1.
[0108] Unlike embodiments of the present invention, when both the electrode layer and the resin layer covering it are arranged on the third surface S3 of the body 110, the resin layer has lower electrical connectivity than the electrode layer, which can lead to an increase in the equivalent series resistance (ESR) of the first external electrode. There is also a risk of floating occurring due to gas outflow from the resin layer during the high-temperature reflow process. Consequently, because the resin layer is present on the electrode layer, the thickness of the external electrode is greater than when only the electrode layer is present, and the relative volume of the ceramic body is smaller, which can lead to a decrease in the effective capacitance of the multilayer ceramic capacitor.
[0109] In contrast, according to the embodiment of the present invention, the first connecting portion 211 is arranged on the third surface S3 of the body 110, and the first conductive resin layer 220 is not arranged on the third surface S3, so the aforementioned problem may not occur.
[0110] The second conductive resin layer 230, the third conductive resin layer 240, and the fourth conductive resin layer 250 contain the same or similar components as the first conductive resin layer 220 described above, and may be formed in the same manner as the first conductive resin layer 220; therefore, repeated explanations regarding them will be omitted.
[0111] The multilayer ceramic capacitor 1000 may further include a first plating layer 280.
[0112] The first plating layer 280 covers the first external electrode 200. The first plating layer 280 may include a first layer 281 and a second layer 283. The first layer 281 may be placed on the first external electrode 200, and the second layer 283 may be placed on the first layer 281. The first layer 281 may contain nickel (Ni), and the second layer 283 may contain tin (Sn), but embodiments of the present invention are not limited thereto.
[0113] The second external electrode 300 includes a second electrode layer 310, a fifth conductive resin layer 320, a sixth conductive resin layer 330, a seventh conductive resin layer 340, and an eighth conductive resin layer 350.
[0114] The second electrode layer 310 contains a metal. The second electrode layer 310 may contain one or more of the following: silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and alloys thereof.
[0115] The second electrode layer 310 includes a second connecting portion 311, a fifth band portion 312, a sixth band portion 313, a seventh band portion 314, and an eighth band portion 315.
[0116] The second connection portion 311 covers the fourth surface S4 of the body 110 and is connected to the exposed ends of the multiple second internal electrodes 160, thereby being electrically coupled.
[0117] The fifth band section 312 extends from the second connecting section 311 and covers a portion of the first surface S1 of the body 110, and the sixth band section 313 extends from the second connecting section 311 and covers a portion of the second surface S2 of the body 110.
[0118] The seventh band section 314 extends from the second connecting section 311 and covers a portion of the fifth surface S5 of the body 110, and the eighth band section 315 extends from the second connecting section 311 and covers a portion of the sixth surface S6 of the body 110.
[0119] The fifth conductive resin layer 320 covers the fifth band portion 312, exposing the second connection portion 311. In other words, the fifth conductive resin layer 320 is not placed on the second connection portion 311.
[0120] For example, the fifth conductive resin layer 320 can cover a part or all of the fifth band portion 312. Alternatively, the fifth conductive resin layer 320 can cover a part of the first surface S1 of the body 110.
[0121] The sixth conductive resin layer 330 covers the sixth band portion 313, exposing the second connection portion 311. In other words, the sixth conductive resin layer 330 is not placed on the second connection portion 311.
[0122] For example, the sixth conductive resin layer 330 can cover a part or all of the sixth band portion 313. Alternatively, the sixth conductive resin layer 330 can cover a part of the second surface S2 of the body 110.
[0123] The outer surface of the fifth conductive resin layer 320 may include a curved surface, and the outer surface of the sixth conductive resin layer 330 may also include a curved surface.
[0124] The fifth conductive resin layer 320 may contain metal and resin.
[0125] The metal contained in the fifth conductive resin layer 320 may include, for example, copper (Cu), silver (Ag), nickel (Ni), tin (Sn), or alloys thereof.
[0126] The resin contained in the fifth conductive resin layer 320 may be a variety of known thermosetting resins, such as epoxy resin, phenolic resin, urethane resin, silicone resin, or polyimide resin.
[0127] The sixth conductive resin layer 330, the seventh conductive resin layer 340, and the eighth conductive resin layer 350 contain the same or similar components as the fifth conductive resin layer 320 described above, so repeated explanations regarding them will be omitted.
[0128] The multilayer ceramic capacitor 1000 may further include a second plating layer 380.
[0129] The second plating layer 380 covers the second external electrode 300. The second plating layer 380 may include a third layer 381 and a fourth layer 383. The third layer 381 may be placed on the second external electrode 300, and the fourth layer 383 may be placed on the third layer 381. The third layer 381 may contain nickel (Ni), and the fourth layer 383 may contain tin (Sn), but embodiments of the present invention are not limited thereto.
[0130] The second external electrode 300 corresponds to the first external electrode 200, except for its position, so repeated explanations regarding it will be omitted.
[0131] Figure 11 is a schematic cross-sectional view showing the multilayer ceramic capacitor shown in Figure 1 mounted on a circuit board.
[0132] Referring to Figure 11, the multilayer ceramic capacitor 1000 is connected to the first electrode pad 511 and the second electrode pad 513 provided on the upper surface of the circuit board 500 via a conductive bonding member 515.
[0133] Here, the second surface S2 of the body 110 becomes the mounting surface, so the multilayer ceramic capacitor 1000 can be electrically connected to the first electrode pad 511 and the second electrode pad 513 of the circuit board 500 with the second conductive resin layer 230 and the sixth conductive resin layer 330 facing the upper surface of the circuit board 500. The conductive bonding member 515 may include solder as an example.
[0134] As described above, embodiments of the present invention have been explained, but the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, the detailed description of the invention, and the attached drawings, and these also naturally fall within the scope of the present invention. [Explanation of Symbols]
[0135] 1000: Multilayer ceramic capacitor 110: Body 200: 1st external electrode 211: First connection section 212: First Band 220: First conductive resin layer 213: 2nd Band 230: Second conductive resin layer 300: 2nd external electrode 311: Second connection section 312: 5th Band 320: 5th conductive resin layer 313: 6th Band 330: 6th conductive resin layer 140: Dielectric layer 143: First Cover Layer 145: Second Cover Layer 150: 1st internal electrode 160:Second internal electrode
Claims
1. A body comprising a plurality of internal electrodes stacked in a first direction with a dielectric layer interposed therebetween, and having a first surface and a second surface arranged on opposite sides of each other in the first direction, External electrodes located outside the body and connected to the plurality of internal electrodes Includes, The aforementioned external electrode is A connecting portion connected to the plurality of internal electrodes in a second direction intersecting the first direction, A first band portion connected to the aforementioned connection portion and covering a part of the first surface, A second band portion connected to the aforementioned connection portion and covering a part of the second surface, A first conductive resin layer that covers the first band portion and exposes the connection portion, and A second conductive resin layer that covers the second band portion and exposes the connection portion. Includes, A multilayer ceramic capacitor in which the thickness of the second conductive resin layer is greater than the thickness of the first conductive resin layer.
2. The multilayer ceramic capacitor according to claim 1, wherein the average thickness of the second conductive resin layer is at least twice the average thickness of the first conductive resin layer.
3. The first conductive resin layer covers a portion of the first band portion, The multilayer ceramic capacitor according to claim 1, wherein the second conductive resin layer covers a portion of the second band portion.
4. The first conductive resin layer covers a portion of the first surface, The multilayer ceramic capacitor according to claim 1, wherein the second conductive resin layer covers a portion of the second surface.
5. In the region where the first conductive resin layer covers the first surface, The multilayer ceramic capacitor according to claim 4, wherein the length of the portion in contact between the first conductive resin layer and the first surface is greater than the thickness of the first conductive resin layer.
6. In the region where the second conductive resin layer covers the second surface, The multilayer ceramic capacitor according to claim 4, wherein the length of the portion in contact between the second conductive resin layer and the second surface is greater than the thickness of the second conductive resin layer.
7. The outer surface of the first conductive resin layer includes a curved surface. The multilayer ceramic capacitor according to claim 1, wherein the outer surface of the second conductive resin layer includes a curved surface.
8. The length of the first conductive resin layer is greater than the length of the first band portion. The multilayer ceramic capacitor according to claim 1, wherein the length of the second conductive resin layer is greater than the length of the second band portion.
9. The length of the first conductive resin layer is greater than the thickness of the first conductive resin layer. The multilayer ceramic capacitor according to claim 1, wherein the length of the second conductive resin layer is greater than the thickness of the second conductive resin layer.
10. If the length of the body is Lc, the thickness of the first conductive resin layer is t1, and the thickness of the second conductive resin layer is t2, The multilayer ceramic capacitor according to claim 1, wherein Lc / 500 ≤ t1 < t2 ≤ Lc / 50.
11. If the length of the body is Lc and the thickness of the connecting portion is Tz, The multilayer ceramic capacitor according to claim 1, wherein Lc / 250 ≤ Tz ≤ Lc / 25.
12. The body includes a third surface and a fourth surface which are arranged on opposite sides of each other in a third direction that intersects the first and second directions simultaneously, The aforementioned external electrode is A third band portion connected to the aforementioned connection portion and covering a part of the third surface, A fourth band portion connected to the aforementioned connection portion and covering a part of the fourth surface, A third conductive resin layer covering the third band portion, and The fourth conductive resin layer covering the fourth band portion It further includes, The multilayer ceramic capacitor according to claim 1, wherein the first conductive resin layer, the third conductive resin layer, and the fourth conductive resin layer have the same average thickness.
13. The multilayer ceramic capacitor according to claim 12, wherein the same average thickness of the first conductive resin layer, the third conductive resin layer, and the fourth conductive resin layer is smaller than the average thickness of the second conductive resin layer.
14. The body includes a third surface and a fourth surface which are arranged on opposite sides of each other in a third direction that intersects the first and second directions simultaneously, The aforementioned external electrode is A third band portion connected to the aforementioned connection portion and covering a part of the third surface, A fourth band portion connected to the aforementioned connection portion and covering a part of the fourth surface, A third conductive resin layer covering the third band portion, and The fourth conductive resin layer covering the fourth band portion It further includes, The multilayer ceramic capacitor according to claim 1, wherein the average thickness of the first conductive resin layer, the average thickness of the third conductive resin layer, and the average thickness of the fourth conductive resin layer are all smaller than the average thickness of the second conductive resin layer.
15. The body includes a third surface and a fourth surface which are arranged on opposite sides of each other in a third direction that intersects the first and second directions simultaneously, The aforementioned external electrode is A third band portion connected to the aforementioned connection portion and covering a part of the third surface, A fourth band portion connected to the aforementioned connection portion and covering a part of the fourth surface, A third conductive resin layer covering the third band portion, and The fourth conductive resin layer covering the fourth band portion It further includes, The multilayer ceramic capacitor according to claim 1, wherein the average thickness of the first conductive resin layer and the average thickness of the fourth conductive resin layer are the same, and are smaller than the average thickness of the second conductive resin layer and the average thickness of the third conductive resin layer.
16. The multilayer ceramic capacitor according to claim 15, wherein the average thickness of the third conductive resin layer is smaller than the average thickness of the second conductive resin layer.
17. The body includes a third surface and a fourth surface which are arranged on opposite sides of each other in a third direction that intersects the first and second directions simultaneously, The aforementioned external electrode is A third band portion connected to the aforementioned connection portion and covering a part of the third surface, A fourth band portion connected to the aforementioned connection portion and covering a part of the fourth surface, A third conductive resin layer covering the third band portion, and The fourth conductive resin layer covering the fourth band portion It further includes, The multilayer ceramic capacitor according to claim 1, wherein the average thickness of the first conductive resin layer and the average thickness of the third conductive resin layer are the same, and are smaller than the average thickness of the second conductive resin layer and the average thickness of the fourth conductive resin layer.
18. The multilayer ceramic capacitor according to claim 17, wherein the average thickness of the fourth conductive resin layer is smaller than the average thickness of the second conductive resin layer.
19. The multilayer ceramic capacitor according to claim 1, wherein the first conductive resin layer and the second conductive resin layer each contain a metal and a resin.
20. The multilayer ceramic capacitor according to claim 1, further comprising a plating layer covering the external electrode.