Capacitor element

Abstract

This capacitor element 1 is provided with: a capacitor part 10 which includes an anode plate 11 that has a porous part 11B on at least one main surface of a core part 11A, a dielectric layer 13 that is provided on the surface of the porous part 11B, and a cathode layer 12 that is provided on the surface of the dielectric layer 13; and a sealing layer 20 which is provided so as to cover at least one main surface of the capacitor part 10. A plurality of penetration parts 30 are provided so as to penetrate the capacitor part 10 and the sealing layer 20 in the thickness direction. A coating layer 40 which has a lower moisture permeability than the sealing layer 20 is provided on at least a part between an insulating material, with which the penetration parts 30 are filled, and a wall surface of the anode plate 11 exposed in the penetration parts 30 and / or at least a part of a side surface of the anode plate 11 exposed at an edge end of the capacitor part 10.

Description

Capacitor element

[0001] The present invention relates to a capacitor element.

[0002] Patent Document 1 discloses a solid electrolytic capacitor including an anode plate made of a valve metal, a porous layer provided on at least one main surface of the anode plate, a dielectric layer provided on the surface of the porous layer, an insulating layer filled inside the porous layer and provided on the surface of the porous layer above the filled portion, and a cathode layer including a solid electrolyte layer provided on the surface of the dielectric layer, wherein the cathode layer is divided into two or more cathode portions, the insulating layer includes a first insulating layer surrounding at least one of the cathode portions as viewed in the thickness direction, and a first penetrating portion is formed so as to penetrate both the porous layer and the first insulating layer in the thickness direction.

[0003] WO 2023 / 276695

[0004] Patent Document 1 describes that a sealing layer may be provided to cover the capacitor layer (hereinafter also referred to as the capacitor portion) from both main surface sides or one main surface side.

[0005] However, because the sealing layer covering the capacitor section contains a resin with high moisture permeability, moisture contained in the capacitor element is likely to penetrate into the porous portion of the anode plate at the exposed portion of the anode plate covered by the sealing layer. If heat is applied to the capacitor element in this state, the expansion of the evaporated moisture may cause a phenomenon known as delamination, such as peeling of the cathode layer from the anode plate.

[0006] The above problem is not limited to a structure in which the cathode layer is divided into two or more cathode portions, but is a problem common to capacitor elements in which the capacitor portion is covered with a sealing layer.

[0007] The present invention has been made to solve the above problems, and has an object to provide a capacitor element that can prevent delamination due to the intrusion of moisture into the anode plate.

[0008] The capacitor element of the present invention comprises an anode plate having a porous portion on at least one main surface of a core portion, a capacitor portion including a dielectric layer provided on the surface of the porous portion, and a cathode layer provided on the surface of the dielectric layer, and a sealing layer provided so as to cover at least one main surface of the capacitor portion, wherein a plurality of through-holes are provided so as to penetrate the capacitor portion and the sealing layer in the thickness direction, and a coating layer having a lower moisture permeability than the sealing layer is provided on at least a portion of the space between the insulating material filled in the through-holes and the wall surface of the anode plate exposed in the through-holes, or on at least a portion of the side surface of the anode plate exposed at the edge of the capacitor portion, or both.

[0009] According to the present invention, it is possible to provide a capacitor element that can prevent delamination due to the intrusion of moisture into the anode plate.

[0010] Fig. 1 is a cross-sectional view schematically showing an example of a capacitor element according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line A-A of the capacitor element shown in Fig. 1. Fig. 3A is a cross-sectional view schematically showing an example of a capacitor element according to a comparative example in which a coating layer is not provided. Fig. 3B is a cross-sectional view schematically showing an example of a capacitor element according to an example in which a coating layer is provided. Fig. 4 is a cross-sectional view schematically showing an example of a capacitor element according to a second embodiment of the present invention.

[0011] The capacitor element of the present invention will be described below. Note that the present invention is not limited to the following embodiments and may be modified as appropriate within the scope of the present invention. Furthermore, a combination of multiple individual preferred configurations described in the following embodiments also constitutes the present invention.

[0012] The following embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. From the second embodiment onwards, descriptions of matters common to the first embodiment will be omitted, and differences will be mainly described. In particular, similar effects resulting from similar configurations will not be mentioned one after the other for each embodiment.

[0013] In the following description, when no particular distinction is made between the embodiments, they will simply be referred to as "the capacitor element of the present invention."

[0014] In this specification, terms indicating the relationship between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms indicating the shapes of elements are not expressions that only express a strict meaning, but are expressions that mean that they are substantially equivalent, for example, including a difference of about a few percent. Furthermore, in this specification, "equivalent" is not an expression that means only complete equivalent, but is an expression that means that they are substantially equivalent, for example, including a difference of about a few percent.

[0015] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, and other scales may differ from those of the actual product. In the drawings, the same or equivalent parts will be designated by the same reference numerals. In addition, the same elements will be designated by the same reference numerals in each drawing, and duplicate explanations will be omitted.

[0016] First Embodiment In a capacitor element according to a first embodiment of the present invention, one capacitor portion is disposed inside a sealing layer.

[0017] Fig. 1 is a cross-sectional view schematically showing an example of a capacitor element according to a first embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along line AA of the capacitor element shown in Fig. 1.

[0018] The capacitor element 1 shown in FIG. 1 includes a capacitor section 10 and a sealing layer 20 provided so as to cover at least one main surface of the capacitor section 10 .

[0019] As shown in FIGS. 1 and 2, one capacitor section 10 is disposed inside the sealing layer 20 .

[0020] The capacitor section 10 includes an anode plate 11 having a porous portion 11B on at least one main surface of a core portion 11A, a dielectric layer 13 provided on the surface of the porous portion 11B, and a cathode layer 12 provided on the surface of the dielectric layer 13. This makes up an electrolytic capacitor. In the example shown in Fig. 1, the anode plate 11 has the porous portion 11B on both main surfaces of the core portion 11A, but the porous portion 11B may be provided on only one main surface of the core portion 11A.

[0021] The cathode layer 12 includes, for example, a solid electrolyte layer 12A provided on the surface of the dielectric layer 13. The cathode layer 12 preferably further includes a conductor layer 12B provided on the surface of the solid electrolyte layer 12A. When the cathode layer 12 includes the solid electrolyte layer 12A, the capacitor section 10 constitutes a solid electrolytic capacitor.

[0022] The sealing layer 20 may be composed of only one layer or two or more layers. When the sealing layer 20 is composed of two or more layers, the materials constituting the respective layers may be the same or different.

[0023] 1, the sealing layer 20 is preferably provided on both principal surfaces that face each other in the thickness direction (Z direction in FIG. 1) of the capacitor section 10. The sealing layer 20 protects the capacitor section 10.

[0024] The sealing layer 20 is formed so as to seal the capacitor portion 10 by, for example, a method of thermocompressing an insulating resin sheet, or a method of applying an insulating resin paste and then thermally curing it.

[0025] The capacitor element 1 is provided with a plurality of through-holes 30 that penetrate the capacitor section 10 and the sealing layer 20 in the thickness direction.

[0026] The through portion 30 may include, for example, a first through hole 31 having a cathode through conductor 35A electrically connected to the cathode layer 12 provided therein, a second through hole 32 having an anode through conductor 35B electrically connected to the anode plate 11 provided therein, or a through groove 33 dividing the anode plate 11. The through portion 30 may include any one or more of the first through hole 31, the second through hole 32, and the through groove 33. The numbers of the first through holes 31, the second through holes 32, and the through grooves 33 are not particularly limited. Although not shown, the through portion 30 may include, for example, a through hole having a through conductor provided therein that is not electrically connected to either the anode plate 11 or the cathode layer 12.

[0027] It is preferable that an insulating material such as a sealing layer 20 is filled between the wall surface of the anode plate 11 exposed in the first through hole 31 and the cathode through conductor 35A. In the example shown in Fig. 1 , the sealing layer 20 is inserted between the wall surface of the anode plate 11 exposed in the first through hole 31 and the cathode through conductor 35A.

[0028] It is preferable that an insulating material such as the sealing layer 20 is not filled between the wall surface of the anode plate 11 exposed in the second through-hole 32 and the anode through-conductor 35B.

[0029] The interior of the through groove 33 is preferably filled with an insulating material such as a sealing layer 20. In the example shown in FIG.

[0030] As shown in FIG. 1, an insulating mask layer 25 may be provided around the through-hole 30 on at least one main surface of the anode plate 11 .

[0031] When an insulating mask layer 25 is provided around the first through hole 31, it is preferable that the insulating mask layer 25 be provided between the insulating material (sealing layer 20 in Figure 1) filled between the cathode through conductor 35A and the capacitor section 10 and the cathode layer 12.

[0032] When the insulating mask layer 25 is provided around the second through-hole 32 , it is preferable that the insulating mask layer 25 be provided between the anode through-conductor 35 B and the cathode layer 12 .

[0033] 1 , an insulating mask layer 25 may be provided on at least one main surface of the anode plate 11 so as to surround the periphery of the cathode layer 12. By surrounding the periphery of the cathode layer 12 with the insulating mask layer 25, insulation between the anode plate 11 and the cathode layer 12 is ensured, and short-circuiting between them is prevented. The insulating mask layer 25 may be provided so as to surround a portion of the periphery of the cathode layer 12, or may be provided so as to surround the entire periphery of the cathode layer 12.

[0034] In the capacitor element 1, a coating layer 40 having a lower moisture permeability than the sealing layer 20 is provided on at least a portion of the space between the insulating material filled in the through portion 30 (in FIG. 1 , the sealing layer 20 that penetrates into the through portion 30) and the wall surface of the anode plate 11 exposed in the through portion 30, or on at least a portion of the side surface of the anode plate 11 exposed at the edge of the capacitor portion 10, or both.

[0035] 3A and 3B are cross-sectional views schematically illustrating an example of a capacitor element according to a comparative example in which a coating layer is not provided, and an example of a capacitor element according to an example in which a coating layer is provided.

[0036] 3A and 3B, an example of a moisture penetration path is shown by an arrow. Note that the moisture penetration path shown in FIGS. 3A and 3B is merely an example, and is not limited to the path shown by the arrow. As shown in FIGS. 3A and 3B, moisture penetrates into the interior through the sealing layer 20, but the upper and lower surfaces of the anode plate 11 are provided with insulating mask layers 25, etc., which make it difficult for moisture to penetrate.

[0037] In the capacitor element 1a according to the comparative example shown in Fig. 3A, moisture is likely to penetrate, for example, from the location indicated by the arrow, into the exposed portion of the anode plate 11. In contrast, in the capacitor element 1 according to the example shown in Fig. 3B, by providing a coating layer 40 on the exposed portion of the anode plate 11, it is possible to suppress moisture penetration into the anode plate 11, for example, from the location indicated by the arrow. As a result, it is possible to prevent delamination due to moisture penetration into the anode plate 11.

[0038] Furthermore, in the capacitor element 1 according to the embodiment shown in FIG. 3B, a coating layer 40 is provided on the exposed portion of the anode plate 11 to suppress the penetration of moisture into the anode plate 11, thereby preventing deterioration of the electrical characteristics due to moisture.

[0039] The coating layer 40 may include only a coating layer 41 provided on at least a portion between the insulating material such as the sealing layer 20 filled in the through-hole 30 and the wall surface of the anode plate 11 exposed in the through-hole 30, or may include only a coating layer 42 provided on at least a portion of the side surface of the anode plate 11 exposed at the edge of the capacitor section 10, or may include both the coating layer 41 and the coating layer 42.

[0040] When the coating layer 41 is provided between the insulating material such as the sealing layer 20 filled in the through portion 30 and the wall surface of the anode plate 11 exposed in the through portion 30, the coating layer 41 may be provided over the entire area between the insulating material filled in the through portion 30 and the wall surface of the anode plate 11 exposed in the through portion 30, or may be provided over a portion of the area between the insulating material filled in the through portion 30 and the wall surface of the anode plate 11 exposed in the through portion 30. Furthermore, there may be a wall surface of the anode plate 11 on which the coating layer 41 is not provided.

[0041] When the through portion 30 includes the first through hole 31, it is preferable that a coating layer 41 is provided on at least a part of the wall surface of the anode plate 11 exposed in the first through hole 31. In this case, it is preferable that an insulating material such as a sealing layer 20 is filled between the coating layer 41 and the cathode through conductor 35A.

[0042] When the through portion 30 includes a through groove 33, it is preferable that a coating layer 41 is provided on at least a part of the wall surface of the anode plate 11 exposed in the through groove 33. In this case, it is preferable that the through groove 33 is filled with an insulating material such as a sealing layer 20.

[0043] When the coating layer 42 is provided on the side surface of the anode plate 11 exposed at the edge of the capacitor section 10, the coating layer 42 may be provided on the entire side surface of the anode plate 11 exposed at the edge of the capacitor section 10, or may be provided on a part of the side surface of the anode plate 11 exposed at the edge of the capacitor section 10. Furthermore, there may be a side surface of the anode plate 11 on which the coating layer 42 is not provided.

[0044] 1 , the edge of the capacitor unit 10 is preferably covered with a sealing layer 20. In this case, a covering layer 42 is preferably provided on at least a portion between the sealing layer 20 covering the edge of the capacitor unit 10 and the side surface of the anode plate 11. In other words, the covering layer 42 provided on at least a portion of the side surface of the anode plate 11 is preferably covered with the sealing layer 20.

[0045] The edge of the capacitor section 10 does not have to be covered with the sealing layer 20. That is, the covering layer 42 provided on at least a part of the side surface of the anode plate 11 may be exposed.

[0046] The coating layer 40 may be composed of only one layer, or may be composed of two or more layers. When the coating layer 40 is composed of two or more layers, the materials constituting each layer may be the same or different. Furthermore, coating layers 40 with different numbers of layers may be mixed.

[0047] From the viewpoint of suppressing the intrusion of moisture into the anode plate 11, it is preferable that the coating layer 40 has a lower moisture permeability than the insulating mask layer 25 provided in the porous portion 11B. In particular, it is preferable that the coating layer 40 has gaps smaller than the size of a water molecule.

[0048] In this specification, the moisture permeability refers to the water vapor permeability measured in accordance with JIS K7129-C (ISO 15106-4).

[0049] Examples of the coating layer 40 include a metal layer, a glass layer, and a ceramic layer. Among these, the coating layer 40 is preferably a metal layer. When the coating layer 40 is a metal layer, the moisture permeability of the coating layer 40 can be made lower than that of the sealing layer 20. This makes it possible to suppress moisture penetration into the anode plate 11 including the porous portion 11B.

[0050] For example, the anode plate 11 is preferably made of aluminum or an aluminum alloy, and the coating layer 40 preferably includes a metal layer containing nickel as a main component. Note that the "main component" refers to the element component with the largest weight ratio.

[0051] For example, the coating layer 40 including a metal layer mainly composed of nickel can be formed by performing a zincate treatment on the wall surface and / or side surface of the anode plate 11 made of aluminum or an aluminum alloy, followed by electroless nickel plating. The coating layer 40 may include, in order from the anode plate 11, a metal layer mainly composed of zinc and a metal layer mainly composed of nickel.

[0052] The dimension of the coating layer 40 in the thickness direction of the anode plate 11 (Z direction in Figure 1) may be equal to the dimension of the anode plate 11 in the thickness direction, may be smaller than the dimension of the anode plate 11 in the thickness direction, or may be larger than the dimension of the anode plate 11 in the thickness direction.

[0053] In the example shown in FIG. 1, the insulating material filled in the through portion 30 is the sealing layer 20 that has entered the through portion 30 , but it may be an insulating material other than the sealing layer 20 .

[0054] The planar shape of the first through-hole 31 (e.g., the cross-sectional shape perpendicular to the thickness direction of the anode plate 11) is not particularly limited and may be, for example, a circular shape. Similarly, the planar shape of the second through-hole 32 is not particularly limited and may be, for example, a circular shape.

[0055] The first through-hole 31 is preferably present in the cathode layer 12 when viewed in plan in the thickness direction of the anode plate 11. Similarly, the second through-hole 32 is preferably present in the cathode layer 12 when viewed in plan in the thickness direction of the anode plate 11.

[0056] The number of first through holes 31 may be the same as the number of second through holes 32 , may be less than the number of second through holes 32 , or may be more than the number of second through holes 32 .

[0057] The diameter of the first through hole 31 may be equal to the diameter of the second through hole 32 , may be smaller than the diameter of the second through hole 32 , or may be larger than the diameter of the second through hole 32 .

[0058] In this specification, the diameter of a through hole means the diameter when the planar shape is circular, and means the equivalent circle diameter when the planar shape is other than circular.

[0059] The diameter of the first through holes 31 may be constant or may vary in the thickness direction. Similarly, the diameter of the second through holes 32 may be constant or may vary in the thickness direction.

[0060] The extending direction of the through grooves 33 is not particularly limited. For example, the through grooves 33 may extend in the X direction, the Y direction, or a direction intersecting the X direction or the Y direction in Figures 1 and 2. The number of through grooves 33 is not particularly limited and may be one, or two or more. The through grooves 33 may be linear, curved, or bent.

[0061] The width of the through groove 33 may be constant or may vary in the thickness direction. The through groove 33 may be arranged so as to cross the anode plate 11, or may be arranged so as not to cross the anode plate 11.

[0062] The cathode through conductor 35A is electrically connected to the cathode layer 12 .

[0063] When viewed in the thickness direction of the anode plate 11, the cathode through conductor 35A is preferably provided around the entire periphery of the through hole as shown in FIG.

[0064] A first resin filling portion 45A filled with a resin material may be provided inside the cathode through conductor 35A. In this case, the first resin filling portion 45A is provided in the space surrounded by the cathode through conductor 35A inside the first through hole 31. When the space inside the first through hole 31 is eliminated by providing the first resin filling portion 45A, the occurrence of delamination of the cathode through conductor 35A is suppressed. Note that the first resin filling portion 45A may be a conductor or an insulator.

[0065] The anode through conductor 35B is electrically connected to the anode plate 11 .

[0066] 1 , the anode penetrating conductor 35B is preferably electrically connected to the wall surface of the anode plate 11 exposed in the second through hole 32. In other words, the anode penetrating conductor 35B is preferably electrically connected to the anode plate 11 on the inner wall surface of the second through hole 32.

[0067] 2, the anode through conductor 35B is preferably provided around the entire periphery of the through hole when viewed from the thickness direction of the anode plate 11. The material constituting the anode through conductor 35B may be the same as or different from the material constituting the cathode through conductor 35A.

[0068] The anode through conductor 35B may be electrically connected to the wall surface of the anode plate 11 via the anode connection layer 43. In this case, the anode connection layer 43 functions as a barrier layer for the anode plate 11, more specifically, as a barrier layer for the core portion 11A and the porous portion 11B. When the anode connection layer 43 functions as a barrier layer for the anode plate 11, dissolution of the anode plate 11 that occurs during chemical treatment for forming a wiring layer (described later) is suppressed, and therefore penetration of the chemical solution into the capacitor portion 10 is suppressed, which tends to improve reliability.

[0069] The anode connection layer 43 preferably includes a metal layer containing nickel as a main component. In this case, damage to the metal (e.g., aluminum) constituting the anode plate 11 is reduced, and the barrier properties of the anode connection layer 43 against the anode plate 11 are likely to be improved.

[0070] For example, the anode connecting layer 43 including a metal layer mainly composed of nickel can be formed by performing a zincate treatment on the wall surface of the anode plate 11 made of aluminum or an aluminum alloy, followed by electroless nickel plating. The anode connecting layer 43 may include, in order from the anode plate 11, a metal layer mainly composed of zinc and a metal layer mainly composed of nickel.

[0071] The dimension of the anode connection layer 43 in the thickness direction of the anode plate 11 (Z direction in Figure 1) may be equal to the dimension of the anode plate 11 in the thickness direction, may be smaller than the dimension of the anode plate 11 in the thickness direction, or may be larger than the dimension of the anode plate 11 in the thickness direction.

[0072] The anode through conductor 35B may be connected directly to the wall surface of the anode plate 11 without the anode connection layer 43 therebetween.

[0073] A second resin filling portion 45B filled with a resin material may be provided inside the anode penetrating conductor 35B. In this case, the second resin filling portion 45B is provided in the space surrounded by the anode penetrating conductor 35B inside the second through hole 32. When the space inside the second through hole 32 is eliminated by providing the second resin filling portion 45B, delamination of the anode penetrating conductor 35B is suppressed. The second resin filling portion 45B may be a conductor or an insulator.

[0074] 1, a first wiring layer 50A and a second wiring layer 50B are provided on the surface of the sealing layer 20. In Fig. 1, the first wiring layer 50A and the second wiring layer 50B are provided on both the upper and lower sides of the capacitor element 1, but they may be provided on only one side.

[0075] The first wiring layer 50A is electrically connected to the cathode through conductor 35A. In the example shown in FIG. 1 , the first wiring layer 50A is electrically connected to the cathode layer 12 through a via conductor 55 that penetrates the sealing layer 20.

[0076] The second wiring layer 50B is electrically connected to the anode penetrating conductor 35B. In the example shown in Fig. 1, the second wiring layer 50B is electrically connected to the anode plate 11 via the anode penetrating conductor 35B.

[0077] Second Embodiment In a capacitor element according to a second embodiment of the present invention, a plurality of capacitor portions are arranged inside a sealing layer.

[0078] FIG. 4 is a cross-sectional view schematically showing an example of a capacitor element according to a second embodiment of the present invention.

[0079] The capacitor element 2 shown in FIG. 4 includes a capacitor section 10 and a sealing layer 20 provided so as to cover at least one main surface of the capacitor section 10 .

[0080] 4, a plurality of capacitor sections 10 are arranged inside sealing layer 20. In the example shown in FIG. 4, two capacitor sections 10 are arranged inside sealing layer 20.

[0081] Adjacent capacitor sections 10 are preferably separated by through grooves 33. In this case, through grooves 33 are preferably filled with an insulating material such as sealing layer 20.

[0082] When adjacent capacitor sections 10 are separated by through groove 33, it is sufficient that adjacent capacitor sections 10 are physically separated by through groove 33. Therefore, adjacent capacitor sections 10 may be electrically separated or electrically connected to each other.

[0083] When multiple capacitor sections 10 are arranged inside sealing layer 20, the multiple capacitor sections 10 may be arranged side by side in a plane direction (i.e., a plane direction parallel to the X-axis and Y-axis) perpendicular to the thickness direction (Z-direction in FIG. 4 ), or may be arranged so as to be stacked in the thickness direction, or a combination of both. The multiple capacitor sections 10 may be arranged regularly or irregularly. The size, shape, etc. of the capacitor sections 10 may be the same, or some or all of them may be different. It is preferable that the configuration of each capacitor section 10 is the same, but capacitor sections 10 with different configurations may be included.

[0084] The number of capacitor sections 10 is not particularly limited as long as it is at least 2. The sizes, shapes, etc. of the capacitor sections 10 may be the same, or some or all of them may be different.

[0085] It is preferable that the capacitor sections 10 have the same configuration, but capacitor sections 10 with different configurations may be included.

[0086] The other configurations are the same as those of the first embodiment.

[0087] The detailed configuration of capacitor elements 1 and 2 will be described below.

[0088] Examples of the planar shape of the capacitor section 10 when viewed from the thickness direction include a rectangle (square or oblong), a quadrangle other than a rectangle, a polygon such as a triangle, a pentagon, or a hexagon, a circle, an ellipse, a combination of these, etc. The planar shape of the capacitor section 10 may also be an L-shape, a C-shape, a stepped shape, etc.

[0089] The anode plate 11 is preferably made of a valve metal that exhibits so-called valve action. Examples of the valve metal include simple metals such as aluminum, tantalum, niobium, titanium, and zirconium, and alloys containing at least one of these metals. Among these, aluminum or an aluminum alloy is preferred.

[0090] The shape of the anode plate 11 is preferably a flat plate, and more preferably a foil. Thus, in this specification, the term "plate-like" includes "foil-like".

[0091] The anode plate 11 may have the porous portion 11B on at least one main surface of the core portion 11A. That is, the anode plate 11 may have the porous portion 11B on only one main surface of the core portion 11A, or may have the porous portion 11B on both main surfaces of the core portion 11A. The porous portion 11B is preferably a porous layer formed on the surface of the core portion 11A, and more preferably an etched layer.

[0092] The thickness of the anode plate 11 before etching is preferably 60 μm or more and 200 μm or less. The thickness of the unetched core portion 11A after etching is preferably 15 μm or more and 70 μm or less. The thickness of the porous portion 11B is designed according to the required withstand voltage and electrostatic capacitance, but the combined thickness of the porous portions 11B on both sides of the core portion 11A is preferably 10 μm or more and 180 μm or less.

[0093] The pore diameter of the porous portion 11B is preferably 10 nm or more and 600 nm or less. The pore diameter of the porous portion 11B refers to the median diameter D50 measured with a mercury porosimeter. The pore diameter of the porous portion 11B can be controlled, for example, by adjusting various etching conditions.

[0094] The dielectric layer 13 provided on the surface of the porous portion 11B is porous, reflecting the surface condition of the porous portion 11B, and has a finely uneven surface shape. The dielectric layer 13 is preferably made of an oxide film of the valve metal. For example, when aluminum foil is used as the anode plate 11, the dielectric layer 13 made of an oxide film can be formed by anodizing the surface of the aluminum foil in an aqueous solution containing ammonium adipate or the like (also called chemical conversion treatment).

[0095] The thickness of the dielectric layer 13 is designed according to the required withstand voltage and capacitance, but is preferably 10 nm or more and 100 nm or less.

[0096] When the cathode layer 12 includes a solid electrolyte layer 12A, examples of materials constituting the solid electrolyte layer 12A include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene), also known as PEDOT, is particularly preferred. The conductive polymer may also contain a dopant such as polystyrene sulfonate (PSS). The solid electrolyte layer 12A preferably includes an inner layer that fills the pores (recesses) of the dielectric layer 13 and an outer layer that covers the dielectric layer 13.

[0097] The thickness of the solid electrolyte layer 12A from the surface of the porous portion 11B is preferably 2 μm or more and 20 μm or less.

[0098] The solid electrolyte layer 12A is formed, for example, by a method of forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 13 using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion liquid of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric layer 13 and drying it.

[0099] The solid electrolyte layer 12A can be formed in a predetermined region by applying the above-mentioned treatment liquid or dispersion liquid to the surface of the dielectric layer 13 by a method such as sponge transfer, screen printing, dispenser application, or inkjet printing.

[0100] When the cathode layer 12 includes the conductor layer 12B, the conductor layer 12B includes at least one layer selected from a conductive resin layer and a metal layer. The conductor layer 12B may be composed of only a conductive resin layer or only a metal layer. The conductor layer 12B preferably covers the entire surface of the solid electrolyte layer 12A.

[0101] The conductive resin layer may be, for example, a conductive adhesive layer containing at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler.

[0102] Examples of the metal layer include a metal plating film and a metal foil. The metal layer is preferably made of at least one metal selected from the group consisting of nickel, copper, silver, and alloys containing these metals as the main component. The term "main component" refers to the elemental component with the largest weight ratio.

[0103] The conductor layer 12B includes, for example, a carbon layer provided on the surface of the solid electrolyte layer 12A and a copper layer provided on the surface of the carbon layer.

[0104] The carbon layer is provided to electrically and mechanically connect the solid electrolyte layer 12A and the copper layer. The carbon layer can be formed in a predetermined region by applying a carbon paste to the surface of the solid electrolyte layer 12A by sponge transfer, screen printing, dispenser application, inkjet printing, or other methods. The thickness of the carbon layer is preferably 2 μm or more and 20 μm or less.

[0105] The copper layer can be formed in a predetermined region by applying a copper paste to the surface of the carbon layer by sponge transfer, screen printing, spray coating, dispenser coating, inkjet printing, etc. The thickness of the copper layer is preferably 2 μm or more and 20 μm or less.

[0106] The cathode through conductor 35A is formed, for example, as follows. First, a first through hole 31 penetrating the capacitor unit 10 in the thickness direction is formed by processing such as drilling or laser processing. Next, an insulating material such as a sealing layer 20 is filled into the first through hole 31. A through hole is formed by processing such as drilling or laser processing in the portion filled with the insulating material. At this time, a through hole having a smaller diameter than the first through hole 31 filled with the insulating material is formed, so that the insulating material is present in the planar direction between the inner wall surface of the subsequently formed through hole and the inner wall surface of the first through hole 31. Then, the inner wall surface of the subsequently formed through hole is metallized with a metal material containing a low-resistance metal such as copper, gold, or silver, thereby forming the cathode through conductor 35A. When forming the cathode through conductor 35A, for example, metallizing the inner wall surface of the through hole by processing such as electroless copper plating or electrolytic copper plating facilitates processing. The cathode through conductor 35A may be formed by filling the through hole with a metal material, a composite material of metal and resin, or the like, in addition to metallizing the inner wall surface of the through hole.

[0107] The anode through conductor 35B is formed, for example, as follows. First, a second through hole 32 penetrating the sealing layer 20 and the capacitor unit 10 in the thickness direction is formed by processing such as drilling or laser processing. Then, the inner wall surface of the second through hole 32 is metallized with a metal material containing a low-resistance metal such as copper, gold, or silver, thereby forming the anode through conductor 35B. When forming the anode through conductor 35B, for example, metallizing the inner wall surface of the second through hole 32 by processing such as electroless copper plating or electrolytic copper plating facilitates processing. Note that the method of forming the anode through conductor 35B may be a method of filling the second through hole 32 with a metal material, a composite material of metal and resin, or the like, in addition to a method of metallizing the inner wall surface of the second through hole 32.

[0108] The sealing layer 20 is made of an insulating material. In this case, the sealing layer 20 preferably contains an insulating resin.

[0109] Examples of the insulating resin contained in the sealing layer 20 include epoxy resin and phenol resin.

[0110] Preferably, the sealing layer 20 further contains a filler.

[0111] Examples of the filler contained in the sealing layer 20 include inorganic fillers such as silica particles and alumina particles.

[0112] Between the capacitor section 10 and the sealing layer 20, for example, a stress relaxation layer, a moisture-proof film, or the like may be provided.

[0113] The insulating mask layer 25 is made of an insulating material, and in this case, the insulating mask layer 25 preferably contains an insulating resin.

[0114] Examples of insulating resins contained in the insulating mask layer 25 include polyphenylsulfone resin, polyethersulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), polyimide resin, polyamideimide resin, epoxy resin, and derivatives or precursors thereof.

[0115] The insulating mask layer 25 may be made of the same resin as the sealing layer 20. Unlike the sealing layer 20, if the insulating mask layer 25 contains an inorganic filler, it may adversely affect the effective capacitance portion of the capacitor section 10. Therefore, it is preferable that the insulating mask layer 25 be made of a resin alone.

[0116] The insulating mask layer 25 can be formed in a predetermined area by applying a mask material, such as a composition containing an insulating resin, to the surface of the porous portion 11B by a method such as sponge transfer, screen printing, dispenser application, or inkjet printing.

[0117] The insulating mask layer 25 may be formed on the porous portion 11B either before or after the dielectric layer 13 is formed.

[0118] Examples of the constituent material of the first wiring layer 50A include a metal material containing a low-resistance metal such as silver, gold, copper, etc. In this case, the first wiring layer 50A is formed by, for example, plating the surface of the cathode through conductor 35A.

[0119] In order to improve the adhesion between the first wiring layer 50A and other members, in this case, the adhesion between the first wiring layer 50A and the cathode through conductor 35A, a mixed material of at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler and a resin may be used as a constituent material of the first wiring layer 50A.

[0120] Examples of the constituent material of the second wiring layer 50B include a metal material containing a low-resistance metal such as silver, gold, copper, etc. In this case, the second wiring layer 50B is formed by, for example, plating the surface of the anode through conductor 35B.

[0121] In order to improve the adhesion between the second wiring layer 50B and other members, in this case, the adhesion between the second wiring layer 50B and the anode penetrating conductor 35B, a mixed material of at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler and a resin may be used as the constituent material of the second wiring layer 50B.

[0122] The constituent materials of the first wiring layer 50A and the second wiring layer 50B are preferably the same at least in terms of type, but may be different from each other.

[0123] When multiple capacitor sections 10 are arranged inside the sealing layer 20, each of the capacitor sections 10 may be provided with a first wiring layer 50A electrically connected to the cathode layer 12 and a second wiring layer 50B electrically connected to the anode plate 11, or at least one of the first wiring layer 50A and the second wiring layer 50B may be provided in common among the multiple capacitor sections 10.

[0124] Examples of materials that can be used to form the via conductors 55 include metal materials containing low-resistance metals such as silver, gold, and copper.

[0125] The via conductor 55 is formed, for example, by plating the inner wall surface of a through hole that penetrates the sealing layer 20 in the thickness direction with the above-mentioned metal material, or by filling it with a conductive paste and then performing a heat treatment.

[0126] The capacitor element of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention with respect to the configuration of the capacitor element, the manufacturing conditions of the capacitor element, and the like.

[0127] The capacitor element of the present invention can be suitably used as a constituent material of a composite electronic component. Such a composite electronic component includes, for example, the capacitor element of the present invention, external electrodes provided on the outer side of the sealing layer of the capacitor element and electrically connected to the anode plate and cathode layer of the capacitor element, and an electronic component connected to the external electrodes.

[0128] In a composite electronic component, the electronic component connected to the external electrode may be a passive element or an active element. Both the passive element and the active element may be connected to the external electrode, or either the passive element or the active element may be connected to the external electrode. Also, a composite of a passive element and an active element may be connected to the external electrode.

[0129] Examples of passive elements include inductors, etc. Examples of active elements include memories, GPUs (Graphical Processing Units), CPUs (Central Processing Units), MPUs (Micro Processing Units), and PMICs (Power Management ICs).

[0130] The capacitor element of the present invention has a sheet-like shape as a whole. Therefore, in a composite electronic component, the capacitor element can be treated like a mounting substrate, and electronic components can be mounted on the capacitor element. Furthermore, by making the electronic components mounted on the capacitor element sheet-like, it is also possible to connect the capacitor element and the electronic components in the thickness direction via through-hole conductors that penetrate each electronic component in the thickness direction. As a result, active elements and passive elements can be configured like a single module.

[0131] For example, a switching regulator can be formed by electrically connecting the capacitor element of the present invention between a voltage regulator including a semiconductor active element and a load to which the converted DC voltage is supplied.

[0132] In a composite electronic component, a circuit layer may be formed on either side of a capacitor matrix sheet on which a plurality of capacitor elements of the present invention are laid out, and the circuit layer may be connected to a passive element or an active element.

[0133] Alternatively, the capacitor element of the present invention may be placed in a cavity provided in a substrate, embedded in resin, and then a circuit layer may be formed on the resin. Another electronic component (a passive element or an active element) may be mounted in another cavity of the same substrate.

[0134] Alternatively, the capacitor element of the present invention may be mounted on a smooth carrier such as a wafer or glass, an outer layer made of resin may be formed, a circuit layer may be formed, and then the capacitor element may be connected to a passive or active element.

[0135] The present specification discloses the following:

[0136] <1> A capacitor element comprising: an anode plate having a porous portion on at least one main surface of a core portion; a dielectric layer provided on a surface of the porous portion; and a cathode layer provided on a surface of the dielectric layer; and a sealing layer provided so as to cover at least one main surface of the capacitor portion, wherein a plurality of through holes are provided so as to penetrate the capacitor portion and the sealing layer in a thickness direction, and a coating layer having a lower moisture permeability than the sealing layer is provided on at least a portion between an insulating material filled in the through holes and a wall surface of the anode plate exposed in the through holes, or on at least a portion of a side surface of the anode plate exposed at an edge of the capacitor portion, or both.

[0137] <2> The capacitor element according to <1>, wherein the through portion includes a first through hole having a cathode through conductor provided therein and electrically connected to the cathode layer, the coating layer is provided on at least a part of the wall surface of the anode plate exposed in the first through hole, and the insulating material is filled between the coating layer and the cathode through conductor.

[0138] <3> The capacitor element according to <1> or <2>, wherein the through portion includes a through groove dividing the anode plate, the coating layer is provided on at least a portion of the wall surface of the anode plate exposed in the through groove, and the through groove is filled with the insulating material.

[0139] <4> The capacitor element according to any one of <1> to <3>, wherein the edge of the capacitor section is covered with the sealing layer, and the covering layer is provided in at least a portion between the sealing layer covering the edge of the capacitor section and the side surface of the anode plate.

[0140] <5> The capacitor element according to any one of <1> to <4>, wherein the coating layer is a metal layer.

[0141] <6> The capacitor element according to any one of <1> to <5>, wherein the anode plate is made of aluminum or an aluminum alloy, and the coating layer includes a metal layer containing nickel as a main component.

[0142] <7> The capacitor element according to any one of <1> to <6>, wherein the through portion includes a second through hole having an anode through conductor provided therein and electrically connected to the anode plate, and the anode through conductor is electrically connected to the wall surface of the anode plate exposed in the second through hole.

[0143] <8> The capacitor element according to any one of <1> to <7>, wherein a plurality of the capacitor units are arranged inside the sealing layer.

[0144] <9> The capacitor element according to any one of <1> to <8>, wherein the insulating material filled in the through portion is the sealing layer that penetrates into the through portion.

[0145] <10> The capacitor element according to any one of <1> to <9>, wherein the cathode layer includes a solid electrolyte layer provided on a surface of the dielectric layer.

[0146] REFERENCE SIGNS LIST 1, 1a, 2 Capacitor element 10 Capacitor portion 11 Anode plate 11A Core portion 11B Porous portion 12 Cathode layer 12A Solid electrolyte layer 12B Conductor layer 13 Dielectric layer 20 Sealing layer 25 Insulating mask layer 30 Penetration portion 31 First through hole 32 Second through hole 33 Through groove 35A Cathode through conductor 35B Anode through conductor 40, 41, 42 Covering layer 43 Anode connection layer 45A First resin filled portion 45B Second resin filled portion 50A First wiring layer 50B Second wiring layer 55 Via conductor

Claims

1. A capacitor element comprising: an anode plate having a porous portion on at least one main surface of a core portion, a dielectric layer provided on the surface of the porous portion, and a cathode layer provided on the surface of the dielectric layer; and a sealing layer provided so as to cover at least one main surface of the capacitor portion, wherein a plurality of through holes are provided so as to penetrate the capacitor portion and the sealing layer in the thickness direction, and a coating layer having a lower moisture permeability than the sealing layer is provided on at least a portion of the space between an insulating material filled in the through holes and a wall surface of the anode plate exposed in the through holes, or on at least a portion of the side surface of the anode plate exposed at an edge of the capacitor portion, or on both.

2. A capacitor element as described in claim 1, wherein the through portion includes a first through hole having a cathode through conductor provided therein and electrically connected to the cathode layer, the coating layer is provided on at least a portion of the wall surface of the anode plate exposed in the first through hole, and the insulating material is filled between the coating layer and the cathode through conductor.

3. A capacitor element as described in claim 1 or 2, wherein the through portion includes a through groove dividing the anode plate, the coating layer is provided on at least a portion of the wall surface of the anode plate exposed in the through groove, and the through groove is filled with the insulating material.

4. A capacitor element according to any one of claims 1 to 3, wherein the edge of the capacitor portion is covered with the sealing layer, and the covering layer is provided in at least a portion between the sealing layer covering the edge of the capacitor portion and the side surface of the anode plate.

5. The capacitor element according to any one of claims 1 to 4, wherein the covering layer is a metal layer.

6. The capacitor element according to any one of claims 1 to 5, wherein the anode plate is made of aluminum or an aluminum alloy, and the coating layer includes a metal layer containing nickel as a main component.

7. A capacitor element as claimed in any one of claims 1 to 6, wherein the through portion includes a second through hole having an anode through conductor provided therein and electrically connected to the anode plate, and the anode through conductor is electrically connected to the wall surface of the anode plate exposed in the second through hole.

8. The capacitor element according to any one of claims 1 to 7, wherein a plurality of the capacitor portions are disposed inside the sealing layer.

9. The capacitor element according to claim 1, wherein the insulating material filled in the through portion is the sealing layer that penetrates into the through portion.

10. The capacitor element according to any one of claims 1 to 9, wherein the cathode layer includes a solid electrolyte layer provided on a surface of the dielectric layer.

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