Capacitor element

Abstract

A capacitor element 1 comprises: a capacitor part 10 that includes a first capacitor layer 10A and a second capacitor layer 10B which face each other in the thickness direction; and a sealing layer 20 that is provided so as to cover at least one main surface of the capacitor part 10. Each of the first capacitor layer 10A and the second capacitor layer 10B includes: a positive electrode plate 11 which has a porous part 11B on at least one main surface of a core part 11A; a dielectric layer 13 which is provided on the surface of the porous part 11B; and a negative electrode layer 12 which is provided on the surface of the dielectric layer 13. The negative electrode layer 12 includes: a solid electrolyte layer 12A which is provided on the surface of the dielectric layer 13; and a conductor layer 12B which is provided on the surface of the solid electrolyte layer 12A. The conductor layer 12B included in the first capacitor layer 10A and facing the second capacitor layer 10B is the same as the conductor layer 12B included in the second capacitor layer 10B and facing the first capacitor layer 10A.

Description

Capacitor element

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

[0002] Patent Document 1 discloses a capacitor array including multiple solid electrolytic capacitor elements formed by dividing a single solid electrolytic capacitor sheet, a sheet-like first sealing layer, and a sheet-like second sealing layer. The solid electrolytic capacitor sheet includes an anode plate made of a valve metal, a porous layer provided on at least one major surface of the anode plate, a dielectric layer provided on the surface of the porous layer, and a cathode layer including a solid electrolyte layer provided on the surface of the dielectric layer, and has first and second major surfaces opposing each other in the thickness direction. The first major surface side of each of the multiple solid electrolytic capacitor elements is disposed on the first sealing layer. The second sealing layer is disposed so as to cover the multiple solid electrolytic capacitor elements on the first sealing layer from the second major surface side. The solid electrolytic capacitor elements are separated by slit-shaped sheet removal portions.

[0003] Japanese Patent Application Laid-Open No. 2020-167361

[0004] In the capacitor array described in Patent Document 1, there is a demand for both a larger capacity and a thinner design than ever before.

[0005] The above problem is not limited to a structure in which a plurality of capacitor sections are arranged in the surface direction, but also occurs in a structure in which a single capacitor section is arranged in the surface direction.

[0006] The present invention has been made to solve the above problems, and has an object to provide a capacitor element that can achieve both large capacitance and thinness.

[0007] The capacitor element of the present invention comprises a capacitor section including a first capacitor layer and a second capacitor layer facing each other in the thickness direction, and a sealing layer provided to cover at least one main surface of the capacitor section. The first capacitor layer and the second capacitor layer each include an anode plate having a porous portion on at least one main surface of a core, a dielectric layer provided on the surface of the porous portion, and a cathode layer provided on the surface of the dielectric layer. The cathode layer includes a solid electrolyte layer provided on the surface of the dielectric layer and a conductor layer provided on the surface of the solid electrolyte layer. The conductor layer in the first capacitor layer facing the second capacitor layer is the same as the conductor layer in the second capacitor layer facing the first capacitor layer.

[0008] According to the present invention, it is possible to provide a capacitor element that can achieve both high capacitance and thinness.

[0009] FIG. 1 is a cross-sectional view schematically illustrating an example of a capacitor element according to a first embodiment of the present invention. FIG. 2 is a plan view taken along line A-A of the capacitor element shown in FIG. 1. FIG. 3 is a cross-sectional view schematically illustrating an example of a capacitor element according to a second embodiment of the present invention. FIG. 4 is a plan view taken along line A-A of the capacitor element shown in FIG. 3. FIG. 5 is a cross-sectional view schematically illustrating an example of a step of preparing an anode plate. FIG. 6 is a cross-sectional view schematically illustrating an example of a step of filling an insulating resin into a porous portion. FIG. 7 is a cross-sectional view schematically illustrating an example of a step of forming a through-hole. FIG. 8 is a cross-sectional view schematically illustrating an example of a step of forming an inner layer of a solid electrolyte layer. FIG. 9 is a cross-sectional view schematically illustrating an example of a step of forming an outer layer of a solid electrolyte layer. FIG. 10 is a cross-sectional view schematically illustrating an example of a step of forming a carbon layer of a conductor layer. FIG. 11 is a cross-sectional view schematically illustrating an example of a step of forming a copper layer of a conductor layer. FIG. 12 is a cross-sectional view schematically illustrating an example of a step of stacking a first capacitor layer and a second capacitor layer. FIG. 13 is a cross-sectional view schematically showing an example of a step of forming a first through hole and a second through hole. FIG. 14 is a cross-sectional view schematically showing an example of a step of forming a first through-hole conductor and a second through-hole conductor. FIG. 15 is a cross-sectional view schematically showing an example of a step of forming a first resin-filled portion and a second resin-filled portion. FIGS. 16A and 16B are cross-sectional views schematically showing an example of a step of forming a first external electrode layer and a second external electrode layer. FIG. 17A is a cross-sectional view schematically showing an example of a step of preparing an anode plate in a first capacitor layer. FIG. 17B is a cross-sectional view schematically showing an example of a step of preparing an anode plate in a second capacitor layer. FIG. 18A is a cross-sectional view schematically showing an example of a step of filling an insulating resin into a porous portion in a first capacitor layer. FIG. 18B is a cross-sectional view schematically showing an example of a step of filling an insulating resin into a porous portion in a second capacitor layer. FIG. 19A is a cross-sectional view schematically showing an example of a step of forming a through groove and a through hole in a first capacitor layer. 19B is a cross-sectional view schematically illustrating an example of a process for forming a through groove in the second capacitor layer, and FIG. 20A is a cross-sectional view schematically illustrating an example of a process for forming an inner layer of the solid electrolyte layer in the first capacitor layer.FIG. 20B is a cross-sectional view schematically showing an example of a process for forming an inner layer of a solid electrolyte layer in a second capacitor layer. FIG. 21A is a cross-sectional view schematically showing an example of a process for forming an outer layer of a solid electrolyte layer in a first capacitor layer. FIG. 21B is a cross-sectional view schematically showing an example of a process for forming an outer layer of a solid electrolyte layer in a second capacitor layer. FIG. 22A is a cross-sectional view schematically showing an example of a process for forming a carbon layer of a conductor layer in a first capacitor layer. FIG. 22B is a cross-sectional view schematically showing an example of a process for forming a carbon layer of a conductor layer in a second capacitor layer. FIG. 23A is a cross-sectional view schematically showing an example of a process for forming a copper layer of a conductor layer in a first capacitor layer. FIG. 23B is a cross-sectional view schematically showing an example of a process for forming a copper layer of a conductor layer in a second capacitor layer. FIG. 24 is a cross-sectional view schematically showing an example of a process for stacking a first capacitor layer and a second capacitor layer. FIG. 25 is a cross-sectional view schematically showing an example of a process for forming a via hole. Fig. 26 is a cross-sectional view schematically showing an example of a process for forming a first through-hole conductor, a second through-hole conductor, and a via conductor. Fig. 27 is a cross-sectional view schematically showing an example of a process for forming a first resin filling portion and a second resin filling portion. Figs. 28A and 28B are cross-sectional views schematically showing an example of a process for forming a first external electrode layer and a second external electrode layer.

[0010] The capacitor element of the present invention will be described below. Note that the present invention is not limited to the following configurations and may be modified as appropriate within the scope of the present invention. In addition, a combination of multiple individual preferred configurations described below also constitutes the present invention.

[0011] 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.

[0012] 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."

[0013] In this specification, terms indicating the relationship between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms indicating the shape of elements are not expressions that only express a strict meaning, but are expressions that also include a range of substantial equivalence, for example, a difference of about a few percent.

[0014] 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.

[0015] [First embodiment] 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 plan view taken along line AA of the capacitor element shown in Fig. 1.

[0016] The capacitor element 1 shown in FIGS. 1 and 2 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 .

[0017] The capacitor section 10 includes a first capacitor layer 10A and a second capacitor layer 10B that face each other in the thickness direction (Z direction).

[0018] In the example shown in FIGS. 1 and 2, one capacitor section 10 is disposed inside the sealing layer 20.

[0019] The number of capacitor units arranged inside sealing layer 20 is not particularly limited, and may be one or more. For example, inside sealing layer 20, a plurality of capacitor units may be arranged in a plane direction (i.e., a plane direction parallel to the X-axis and Y-axis) perpendicular to the thickness direction (Z-direction).

[0020] 1, the sealing layer 20 is preferably provided on both opposing main surfaces (top and bottom surfaces in FIG. 1) of the capacitor section 10 in the thickness direction. The sealing layer 20 protects the capacitor section 10.

[0021] 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.

[0022] 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.

[0023] Each of the first capacitor layer 10A and the second capacitor layer 10B 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. 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 anode plate 11 may have the porous portion 11B on only one main surface of the core portion 11A.

[0024] Cathode layer 12 includes solid electrolyte layer 12A provided on the surface of dielectric layer 13, and conductor layer 12B provided on the surface of solid electrolyte layer 12A. Since cathode layer 12 includes solid electrolyte layer 12A, capacitor section 10 constitutes a solid electrolytic capacitor.

[0025] Examples of materials constituting the solid electrolyte layer 12A include conductive polymers such as poly(3,4-ethylenedioxythiophene) known as PEDOT. 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.

[0026] The conductor layer 12B includes, for example, a carbon layer 12Ba provided on the surface of the solid electrolyte layer 12A, and a copper layer 12Bb provided on the surface of the carbon layer 12Ba.

[0027] The conductive layer 12B in the first capacitor layer 10A that faces the second capacitor layer 10B is the same as the conductive layer 12B in the second capacitor layer 10B that faces the first capacitor layer 10A. Note that if the conductive layer 12B is composed of two or more layers, it is sufficient that at least one layer is the same. In other words, the first capacitor layer 10A and the second capacitor layer 10B share the same conductive layer 12B disposed between them.

[0028] 1, the copper layer 12Bb in the first capacitor layer 10A that faces the second capacitor layer 10B is the same as the copper layer 12Bb in the second capacitor layer 10B that faces the first capacitor layer 10A. In other words, the first capacitor layer 10A and the second capacitor layer 10B share the same copper layer 12Bb disposed between them.

[0029] By stacking the first capacitor layer 10A and the second capacitor layer 10B in the thickness direction, it is possible to increase the capacitance per area of ​​the capacitor section 10. Furthermore, by making the conductive layer 12B in the first capacitor layer 10A that faces the second capacitor layer 10B the same as the conductive layer 12B in the second capacitor layer 10B that faces the first capacitor layer 10A, it is possible to reduce the thickness of the entire element. Therefore, it is possible to achieve both large capacitance and thinness.

[0030] Furthermore, since the conductive layer 12B in the first capacitor layer 10A facing the second capacitor layer 10B is the same as the conductive layer 12B in the second capacitor layer 10B facing the first capacitor layer 10A, the element can be made of a material with high thermal conductivity without disposing a thermal insulating material between the first capacitor layer 10A and the second capacitor layer 10B, thereby improving the heat dissipation of the element.

[0031] If the conductive layer 12B in the first capacitor layer 10A facing the second capacitor layer 10B is different from the conductive layer 12B in the second capacitor layer 10B facing the first capacitor layer 10A, wiring is required to electrically connect the first capacitor layer 10A and the second capacitor layer 10B, which increases contact resistance. In contrast, if the conductive layer 12B in the first capacitor layer 10A facing the second capacitor layer 10B is the same as the conductive layer 12B in the second capacitor layer 10B facing the first capacitor layer 10A, there are fewer contact points with different materials, which reduces the series resistance component and allows for a lower equivalent series resistance (ESR).

[0032] Furthermore, if the conductive layer 12B in the first capacitor layer 10A facing the second capacitor layer 10B is different from the conductive layer 12B in the second capacitor layer 10B facing the first capacitor layer 10A, wiring is required to electrically connect the first capacitor layer 10A and the second capacitor layer 10B, which increases the inductance component. In contrast, if the conductive layer 12B in the first capacitor layer 10A facing the second capacitor layer 10B is the same as the conductive layer 12B in the second capacitor layer 10B facing the first capacitor layer 10A, the inductance component is reduced, thereby suppressing noise generation.

[0033] As shown in FIGS. 1 and 2, the capacitor element 1 may further include a first external electrode layer 31 electrically connected to the cathode layer 12 of the first capacitor layer 10A and the cathode layer 12 of the second capacitor layer 10B.

[0034] The first external electrode layer 31 is provided on at least one of the main surfaces of the sealing layer 20. In the example shown in Fig. 1 , the first external electrode layer 31 is provided on both main surfaces of the sealing layer 20 (top and bottom surfaces in Fig. 1 ), but it may be provided on either one of the main surfaces of the sealing layer 20 (top or bottom surface in Fig. 1 ).

[0035] One first external electrode layer 31 may be provided for one capacitor section 10, or a plurality of first external electrode layers 31 may be provided.

[0036] The planar shape of the first external electrode layer 31 when viewed from the thickness direction is not particularly limited, and examples thereof 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. Furthermore, the planar shape of the first external electrode layer 31 may be an L-shape, a C-shape, a stepped shape, etc.

[0037] As shown in FIGS. 1 and 2, the capacitor element 1 may further include a second external electrode layer 32 electrically connected to the anode plate 11 of the first capacitor layer 10A and the anode plate 11 of the second capacitor layer 10B.

[0038] The second external electrode layer 32 is provided on at least one of the main surfaces of the sealing layer 20. In the example shown in Fig. 1 , the second external electrode layer 32 is provided on both main surfaces of the sealing layer 20 (top and bottom surfaces in Fig. 1 ), but it may be provided on either one of the main surfaces of the sealing layer 20 (top or bottom surface in Fig. 1 ).

[0039] One or more second external electrode layers 32 may be provided for one capacitor section 10. The number of second external electrode layers 32 for one capacitor section 10 may be the same as or different from the number of first external electrode layers 31.

[0040] The planar shape of the second external electrode layer 32 when viewed from the thickness direction is not particularly limited, and examples thereof 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, or a combination of these. The planar shape of the second external electrode layer 32 may also be an L-shape, a C-shape, a stepped shape, or the like. The planar shape of the second external electrode layer 32 when viewed from the thickness direction may be the same as or different from the planar shape of the first external electrode layer 31 when viewed from the thickness direction.

[0041] When viewed in a plane from the thickness direction, it is preferable that the first external electrode layer 31 is arranged so that it at least partially overlaps with the same conductor layer 12B (in Figure 1, the same copper layer 12Bb shared by the first capacitor layer 10A and the second capacitor layer 10B).

[0042] By arranging the first external electrode layer 31 so that at least a portion thereof overlaps with the same conductor layer 12B, moisture is less likely to penetrate into the inside of the element, and therefore peeling called delamination, which occurs due to rapid evaporation of moisture, can be suppressed.

[0043] Furthermore, by arranging at least a portion of the first external electrode layer 31 so as to overlap the same conductor layer 12B, the permeation of moisture, oxygen, etc. into the inside of the element is suppressed, thereby suppressing deterioration of the conductive polymer contained in the solid electrolyte layer 12A.

[0044] Furthermore, when at least a portion of the first external electrode layer 31 is arranged to overlap with the same conductor layer 12B, the area of ​​the first external electrode layer 31 is increased and a cathode layer 12 is also formed inside the element, thereby reducing the generation or emission of noise.

[0045] From the viewpoint of suppressing the intrusion of moisture and the like into the interior of the element, it is preferable that the area of ​​the portion of the first external electrode layer 31 overlapping with the same conductor layer 12B be large. For example, in a plan view from the thickness direction, of the area of ​​the first external electrode layer 31 provided on either main surface of the sealing layer 20, the area of ​​the portion of the first external electrode layer 31 overlapping with the same conductor layer 12B is preferably 50% or more of the area of ​​the same conductor layer 12B. For example, of the area of ​​the first external electrode layer 31 provided on the upper surface of the sealing layer 20, the area of ​​the portion of the first external electrode layer 31 overlapping with the same conductor layer 12B may be 50% or more of the area of ​​the same conductor layer 12B. Alternatively, of the area of ​​the first external electrode layer 31 provided on the lower surface of the sealing layer 20, the area of ​​the portion of the first external electrode layer 31 overlapping with the same conductor layer 12B may be 50% or more of the area of ​​the same conductor layer 12B. On the other hand, when viewed in a plane from the thickness direction, the area of ​​the first external electrode layer 31 provided on either main surface of the sealing layer 20, of the portion overlapping with the same conductor layer 12B, is not particularly limited to an upper limit, as long as it is 100% or less of the area of ​​the same conductor layer 12B.

[0046] 1 , when the first external electrode layers 31 are provided on both main surfaces of the sealing layer 20, the above-mentioned area ratios may be the same or different between one main surface side and the other main surface side of the sealing layer 20. Therefore, even if the area of ​​the first external electrode layers 31 provided on either main surface of the sealing layer 20, that is, the area of ​​the portions of the first external electrode layers 31 that overlap with the same conductor layers 12B, is 50% or more of the area of ​​the same conductor layers 12B, the area of ​​the first external electrode layers 31 provided on the other main surface of the sealing layer 20, that is, the area of ​​the portions of the first external electrode layers 31 that overlap with the same conductor layers 12B may be less than 50% of the area of ​​the same conductor layers 12B. However, it is preferable that, among the area of ​​the first external electrode layer 31 provided on either main surface of the sealing layer 20, the area of ​​the portion of the first external electrode layer 31 that overlaps with the same conductor layer 12B is 50% or more of the area of ​​the same conductor layer 12B, and that, among the area of ​​the first external electrode layer 31 provided on the other main surface of the sealing layer 20, the area of ​​the portion of the first external electrode layer 31 that overlaps with the same conductor layer 12B is 50% or more of the area of ​​the same conductor layer 12B.

[0047] Alternatively, in a plan view from the thickness direction, at least one of the first external electrode layer 31 and the second external electrode layer 32 may be disposed so as to at least partially overlap the same conductor layer 12B (the same copper layer 12Bb shared by the first capacitor layer 10A and the second capacitor layer 10B in FIG. 1 ). In this case as well, the permeation of moisture, oxygen, etc. into the interior of the element is suppressed.

[0048] From the viewpoint of suppressing the intrusion of moisture and the like into the interior of the element, it is preferable that the total area of ​​all of the first external electrode layers 31 and second external electrode layers 32 provided on either main surface of the sealing layer 20 in a plan view from the thickness direction be 50% or more of the area surrounded by the outer peripheral edge of the sealing layer 20. For example, the total area of ​​all of the first external electrode layers 31 and second external electrode layers 32 provided on the upper surface of the sealing layer 20 may be 50% or more of the area surrounded by the outer peripheral edge of the sealing layer 20, or the total area of ​​all of the first external electrode layers 31 and second external electrode layers 32 provided on the lower surface of the sealing layer 20 may be 50% or more of the area surrounded by the outer peripheral edge of the sealing layer 20. On the other hand, the total area of ​​all of the first external electrode layers 31 and second external electrode layers 32 provided on either main surface of the sealing layer 20 in a plan view from the thickness direction is, for example, 80% or less of the area surrounded by the outer peripheral edge of the sealing layer 20.

[0049] The "total area of ​​all the first external electrode layers 31 and second external electrode layers 32 provided on either main surface of the sealing layer 20" also includes the area of ​​the first external electrode layers 31 and second external electrode layers 32 that do not overlap with the same conductor layer 12B on the target main surface. Also, the "area surrounded by the outer periphery of the sealing layer 20" does not refer to the area of ​​the sealing layer 20 itself, but rather refers to the total area surrounded by the outer periphery of the sealing layer 20.

[0050] 1 , when the first external electrode layers 31 and / or the second external electrode layers 32 are provided on both main surfaces of the sealing layer 20, the above-mentioned area ratios may be the same or different between one main surface side and the other main surface side of the sealing layer 20. Therefore, even if the total area of ​​all of the first external electrode layers 31 and second external electrode layers 32 provided on one main surface of the sealing layer 20 is 50% or more of the area surrounded by the outer peripheral edge of the sealing layer 20, the total area of ​​all of the first external electrode layers 31 and second external electrode layers 32 provided on the other main surface of the sealing layer 20 may be less than 50% of the area surrounded by the outer peripheral edge of the sealing layer 20. However, it is preferable that the total area of ​​all first external electrode layers 31 and second external electrode layers 32 provided on either main surface of the sealing layer 20 is 50% or more of the area surrounded by the outer peripheral edge of the sealing layer 20, and that the total area of ​​all first external electrode layers 31 and second external electrode layers 32 provided on the other main surface of the sealing layer 20 is 50% or more of the area surrounded by the outer peripheral edge of the sealing layer 20.

[0051] As shown in FIG. 1 , the capacitor element 1 may further include a first through-hole conductor 41 electrically connected to the first external electrode layer 31 .

[0052] The first through-hole conductor 41 may be provided on at least the inner wall surface of the first through hole 51 that penetrates the capacitor section 10 and the sealing layer 20 in the thickness direction. The first through-hole conductor 41 may be provided only on the inner wall surface of the first through hole 51, or may be provided throughout the entire interior of the first through hole 51.

[0053] In plan view from the thickness direction, one first through-hole conductor 41 may be provided inside the cathode layer 12, or two or more first through-hole conductors 41 may be provided inside the cathode layer 12.

[0054] As shown in FIG. 1, the end face of the anode plate 11 and the first through-hole conductor 41 are preferably insulated from each other by an insulating material.

[0055] As shown in FIG. 1, the first through-hole conductor 41 is preferably electrically connected to the cathode layer 12 of the first capacitor layer 10A and the cathode layer 12 of the second capacitor layer 10B on the inner wall surface of the first through hole 51.

[0056] 1 , when the first through-hole conductor 41 is provided only on the inner wall surface of the first through hole 51, a first resin filling portion 61 formed by filling a resin material may be provided inside the first through-hole conductor 41. In this case, the first resin filling portion 61 is provided in the space surrounded by the first through-hole conductor 41 inside the first through hole 51. When the space inside the first through hole 51 is eliminated by providing the first resin filling portion 61, the occurrence of delamination of the first through-hole conductor 41 is suppressed. Note that the first resin filling portion 61 may be a conductor or an insulator.

[0057] As shown in FIG. 1 , the capacitor element 1 may further include a second through-hole conductor 42 electrically connected to the second external electrode layer 32 .

[0058] The second through-hole conductor 42 may be provided on at least the inner wall surface of the second through hole 52 that penetrates the capacitor section 10 and the sealing layer 20 in the thickness direction. The second through-hole conductor 42 may be provided only on the inner wall surface of the second through hole 52, or may be provided throughout the entire interior of the second through hole 52.

[0059] In plan view from the thickness direction, one second through-hole conductor 42 may be provided inside the cathode layer 12, or two or more second through-hole conductors 42 may be provided.

[0060] As shown in FIG. 1, the end face of the cathode layer 12 and the second through-hole conductor 42 are preferably insulated from each other by an insulating material.

[0061] As shown in FIG. 1, the second through-hole conductor 42 is preferably electrically connected to the anode plate 11 of the first capacitor layer 10A and the anode plate 11 of the second capacitor layer 10B on the inner wall surface of the second through hole 52.

[0062] 1 , when the second through-hole conductor 42 is provided only on the inner wall surface of the second through hole 52, a second resin filling portion 62 formed by filling a resin material may be provided inside the second through-hole conductor 42. In this case, the second resin filling portion 62 is provided in the space surrounded by the second through-hole conductor 42 inside the second through hole 52. When the space inside the second through hole 52 is eliminated by providing the second resin filling portion 62, the occurrence of delamination of the second through-hole conductor 42 is suppressed. Note that the second resin filling portion 62 may be a conductor or an insulator.

[0063] Although not shown in FIG. 1, the capacitor element 1 may further include a third through-hole conductor that is not electrically connected to the anode plate 11 and the cathode layer 12 .

[0064] Although not shown in FIG. 1 , capacitor element 1 may further include a via conductor that penetrates sealing layer 20 in the thickness direction and has one end extending to the surface of sealing layer 20 .

[0065] For example, the capacitor element 1 may include a via conductor electrically connected to the anode plate 11. In this case, the anode plate 11 is electrically led out to the outside of the sealing layer 20 through the via conductor, and can be electrically connected to the outside of the sealing layer 20. The number of via conductors electrically connected to the anode plate 11 may be one, or two or more.

[0066] Alternatively, capacitor element 1 may include a via conductor electrically connected to cathode layer 12. In this case, cathode layer 12 is electrically led out of sealing layer 20 through the via conductor, and can be electrically connected to the outside of sealing layer 20. The number of via conductors electrically connected to cathode layer 12 may be one, or two or more.

[0067] When a first through-hole conductor 41 or a second through-hole conductor 42 is provided inside the sealing layer 20, the capacitor section 10 may further include an insulating mask layer provided around the first through-hole conductor 41 or the second through-hole conductor 42 on at least one main surface of the anode plate 11.

[0068] The capacitor section 10 may further include an insulating mask layer 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, insulation between the anode plate 11 and the cathode layer 12 is ensured, and short-circuiting between them is prevented. The insulating mask layer may be provided so as to surround a portion of the periphery of the cathode layer 12, but is preferably provided so as to surround the entire periphery of the cathode layer 12.

[0069] Second Embodiment In a capacitor element according to a second embodiment of the present invention, the areas of the capacitance portions of the first and second capacitor layers are different. When a plurality of capacitor layers are arranged in the planar direction, it is sufficient that the areas of the capacitance portions of at least one capacitor layer are different between the first and second capacitor layers.

[0070] Fig. 3 is a cross-sectional view schematically showing an example of a capacitor element according to a second embodiment of the present invention, and Fig. 4 is a plan view taken along line AA of the capacitor element shown in Fig. 3.

[0071] In the capacitor element 2 shown in FIGS. 3 and 4, two capacitor sections 10 and 10 ′ are arranged inside the sealing layer 20 .

[0072] As shown in Fig. 3, the sealing layer 20 is preferably provided on both opposing main surfaces (top and bottom surfaces in Fig. 3) of the capacitor unit 10 and the capacitor unit 10' in the thickness direction. The sealing layer 20 protects the capacitor unit 10 and the capacitor unit 10'.

[0073] The capacitor section 10 includes a first capacitor layer 10A and a second capacitor layer 10B that face each other in the thickness direction (Z direction).

[0074] Similarly, the capacitor section 10' includes a first capacitor layer 10A and a second capacitor layer 10B that face each other in the thickness direction (Z direction).

[0075] In the capacitor unit 10, the first capacitor layer 10A and the second capacitor layer 10B each include 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. 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 core portion 11A may have the porous portion 11B on only one main surface of the core portion 11A. The same applies to the capacitor unit 10'.

[0076] In the capacitor unit 10, the cathode layer 12 includes a solid electrolyte layer 12A provided on the surface of the dielectric layer 13 and a conductor layer 12B provided on the surface of the solid electrolyte layer 12A. The cathode layer 12 includes the solid electrolyte layer 12A, so that the capacitor unit 10 constitutes a solid electrolytic capacitor. The same applies to the capacitor unit 10′.

[0077] In the capacitor section 10, the conductive layer 12B in the first capacitor layer 10A that faces the second capacitor layer 10B is the same as the conductive layer 12B in the second capacitor layer 10B that faces the first capacitor layer 10A. Note that if the conductive layer 12B is composed of two or more layers, it is sufficient that at least one layer is the same. In other words, it can be said that the first capacitor layer 10A and the second capacitor layer 10B share the same conductive layer 12B disposed between them.

[0078] 3, in the capacitor section 10, the copper layer 12Bb in the first capacitor layer 10A that faces the second capacitor layer 10B is the same as the copper layer 12Bb in the second capacitor layer 10B that faces the first capacitor layer 10A. In other words, it can be said that the first capacitor layer 10A and the second capacitor layer 10B share the same copper layer 12Bb disposed between them.

[0079] In the capacitor section 10', the conductive layer 12B in the first capacitor layer 10A that faces the second capacitor layer 10B is the same as the conductive layer 12B in the second capacitor layer 10B that faces the first capacitor layer 10A. Note that if the conductive layer 12B is composed of two or more layers, it is sufficient that at least one of the layers is the same. In other words, it can be said that the first capacitor layer 10A and the second capacitor layer 10B share the same conductive layer 12B disposed between them.

[0080] 3, in the capacitor section 10′, the copper layer 12Bb in the first capacitor layer 10A that faces the second capacitor layer 10B is the same as the copper layer 12Bb in the second capacitor layer 10B that faces the first capacitor layer 10A. In other words, the first capacitor layer 10A and the second capacitor layer 10B share the same copper layer 12Bb disposed between them.

[0081] In the capacitor section 10', the areas of the capacitance sections of the first capacitor layer 10A and the second capacitor layer 10B are different.

[0082] By making the areas of the capacitance sections of the first capacitor layer 10A and the second capacitor layer 10B different, as in the capacitor section 10', it is possible to meet complex requirements for capacitor capacitance, thereby increasing the degree of freedom in designing the capacitor element.

[0083] In the capacitor section 10, the areas of the capacitance sections of the first capacitor layer 10A and the second capacitor layer 10B may be the same or different.

[0084] The number of capacitor units arranged inside sealing layer 20 is not particularly limited, and may be one or more. For example, inside sealing layer 20, a plurality of capacitor units may be arranged in a plane direction (i.e., a plane direction parallel to the X-axis and Y-axis) perpendicular to the thickness direction (Z-direction).

[0085] When a plurality of capacitor portions are arranged in the planar direction, it is preferable that adjacent capacitor portions in the planar direction are separated by a through groove 80. In this case, it is preferable that the through groove 80 is filled with an insulating material such as a sealing layer 20.

[0086] When capacitor sections 10 adjacent to each other in the planar direction are separated by a through groove 80, it is sufficient that capacitor sections 10 adjacent to each other in the planar direction are physically separated by the through groove 80. Therefore, capacitor sections 10 adjacent to each other in the planar direction may be electrically separated or electrically connected. The width of the through groove 80, i.e., the distance between capacitor sections adjacent to each other in the planar direction, may be constant in the thickness direction (Z direction) or may decrease in the thickness direction.

[0087] When a plurality of capacitor parts are arranged in the plane direction, the capacitor parts may be arranged regularly or irregularly. The size, shape, etc. of the capacitor parts may be the same, or some or all of them may be different. The configuration of each capacitor part is preferably the same, but capacitor parts with different configurations may be included.

[0088] As shown in FIG. 3, the first capacitor layer 10A of the capacitor section 10' may be provided with a first through-hole conductor 41 that reaches the same conductive layer 12B.

[0089] The first through-hole conductor 41 of the capacitor section 10′ may be provided at least on the inner wall surface of the first via hole 81. The first through-hole conductor 41 may be provided only on the inner wall surface of the first via hole 81, or may be provided throughout the entire interior of the first via hole 81.

[0090] In plan view from the thickness direction, one first through-hole conductor 41 may be provided inside the cathode layer 12 of the capacitor section 10', or two or more first through-hole conductors 41 may be provided.

[0091] As shown in FIG. 3, it is preferable that the end face of the anode plate 11 of the capacitor section 10' and the first through-hole conductor 41 are insulated from each other by an insulating material.

[0092] As shown in Figure 3, when the first through-hole conductor 41 of the capacitor section 10' is provided only on the inner wall surface of the first via hole 81, a first resin filling section 61 filled with a resin material may be provided inside the first through-hole conductor 41.

[0093] Furthermore, the first capacitor layer 10A of the capacitor section 10' may be provided with a via conductor 70 that reaches the conductive layer 12B on the opposite side to the same conductive layer 12B.

[0094] In plan view from the thickness direction, one via conductor 70 may be provided inside the cathode layer 12 of the capacitor section 10', or two or more via conductors 70 may be provided.

[0095] Furthermore, a second through-hole conductor 42 reaching the core 11A of the anode plate 11 may be provided in the first capacitor layer 10A of the capacitor section 10'.

[0096] The second through-hole conductor 42 of the capacitor section 10′ may be provided at least on the inner wall surface of the second via hole 82. The second through-hole conductor 42 may be provided only on the inner wall surface of the second via hole 82, or may be provided throughout the entire interior of the second via hole 82.

[0097] In plan view from the thickness direction, one second through-hole conductor 42 may be provided inside the cathode layer 12 of the capacitor section 10', or two or more second through-hole conductors 42 may be provided.

[0098] As shown in FIG. 3, it is preferable that the end face of the cathode layer 12 of the capacitor section 10' and the second through-hole conductor 42 are insulated from each other by an insulating material.

[0099] As shown in Figure 3, when the second through-hole conductor 42 of the capacitor section 10' is provided only on the inner wall surface of the second via hole 82, a second resin filling section 62 filled with a resin material may be provided inside the second through-hole conductor 42.

[0100] The method for producing the capacitor element of the present invention will be described below.

[0101] First, an example of a method for manufacturing the capacitor element 1 shown in FIG. 1 will be described as an example of a method for manufacturing the capacitor element according to the first embodiment of the present invention.

[0102] FIG. 5 is a cross-sectional view schematically showing an example of a step of preparing an anode plate.

[0103] In the step shown in FIG. 5, an anode plate 11 made of a valve metal is prepared.

[0104] For example, an anode plate 11 having a core portion 11A and porous portions 11B provided on both main surfaces thereof is anodized to form a dielectric layer (not shown) on the surface of the porous portions 11B.

[0105] Alternatively, a chemically formed foil may be prepared as the anode plate 11 having a dielectric layer (not shown) provided on the surface of the porous portion 11B.

[0106] FIG. 6 is a cross-sectional view schematically showing an example of a process for filling the inside of the porous portion with insulating resin.

[0107] In the step shown in FIG. 6, an insulating resin such as polyimide resin is applied to a predetermined position on the upper surface of the porous portion 11B, and the insulating resin is allowed to permeate into the interior of the porous portion 11B.

[0108] FIG. 7 is a cross-sectional view schematically showing an example of a step of forming a through hole.

[0109] 7, a through hole 50A is formed by a laser or the like in a portion where the first through-hole conductor is to be formed, and a through hole 50B is formed in a portion where the second through-hole conductor is to be formed. As shown in FIG. 7, the diameter of the through hole 50A is preferably larger than the diameter of the through hole 50B.

[0110] FIG. 8 is a cross-sectional view schematically illustrating an example of a process for forming an inner layer of a solid electrolyte layer.

[0111] 8, a dispersion of PEDOT / PSS, an example of a conductive polymer, is applied to the porous portion 11B surrounded by the insulating resin, allowed to penetrate, and then dried and solidified. This process is repeated until the porous portion 11B is filled with PEDOT / PSS. This forms the inner layer 12Aa of the solid electrolyte layer.

[0112] FIG. 9 is a cross-sectional view schematically illustrating an example of a step of forming an outer layer of a solid electrolyte layer.

[0113] 9, a highly viscous PEDOT / PSS dispersion is applied and then dried and solidified. This forms the outer layer 12Ab of the solid electrolyte layer. The solid electrolyte layer 12A is formed by the inner layer 12Aa and the outer layer 12Ab.

[0114] Furthermore, as shown in FIG. 9, insulating resin is applied to the surface of the insulating resin that has permeated the porous portion 11B, the inside of the through-holes 50A, and the inside of the through-holes 50B, and is then solidified.

[0115] FIG. 10 is a cross-sectional view schematically showing an example of a process for forming a carbon layer of a conductive layer.

[0116] 10, a conductive resin containing a carbon filler is applied to the surface of the solid electrolyte layer 12A and then solidified, thereby forming a carbon layer 12Ba.

[0117] Furthermore, as shown in FIG. 10, an insulating resin is applied to the periphery of the carbon layer 12Ba and is then solidified.

[0118] FIG. 11 is a cross-sectional view schematically showing an example of a step of forming a copper layer of a conductor layer.

[0119] 11, a conductive resin containing copper filler is applied to the surface of the carbon layer 12Ba and then solidified. This forms the copper layer 12Bb. The carbon layer 12Ba and the copper layer 12Bb form the conductor layer 12B.

[0120] 11, an insulating resin is applied around the copper layer 12Bb and then solidified. At this time, it is preferable to adjust the height so that the copper layer 12Bb and the insulating resin are as flat as possible.

[0121] Two substrates having the structure shown in Fig. 11 are prepared. One substrate constitutes the first capacitor layer, and the other substrate constitutes the second capacitor layer.

[0122] FIG. 12 is a cross-sectional view schematically illustrating an example of a process for laminating the first capacitor layer and the second capacitor layer.

[0123] In the step shown in FIG. 12, the first capacitor layer 10A and the second capacitor layer 10B are stacked together with the front and rear conductive layers 12B aligned.

[0124] 12, an insulating resin sheet such as Ajinomoto Build-up Film (ABF) is laminated on the surface of the laminate. After lamination, the laminate is placed in a mold, vacuum degassed, and then thermocompressed and cured. This forms the sealing layer 20.

[0125] FIG. 13 is a cross-sectional view schematically illustrating an example of a step of forming the first through hole and the second through hole.

[0126] 13, a first through hole 51 having a diameter of about 100 μm is formed at a predetermined position where the insulating resin has been formed using a laser such as a UV laser. The copper layer 12Bb is exposed on the side surface of the first through hole 51.

[0127] Separately, a second through-hole 52 having a diameter of about 100 μm is formed at a predetermined position on the insulating resin using a laser such as a UV laser. The anode plate 11 is exposed to the side surface of the second through-hole 52.

[0128] FIG. 14 is a cross-sectional view schematically showing an example of a step of forming the first through-hole conductor and the second through-hole conductor.

[0129] 14, the inner circumferential surface of the first through hole 51 is subjected to, for example, electroless copper plating, followed by electrolytic copper plating, thereby forming the first through-hole conductor 41.

[0130] On the other hand, the second through-hole 52 is subjected to, for example, a zincate treatment, followed by nickel plating and electroless copper plating, and then electrolytic copper plating, thereby forming the second through-hole conductor 42.

[0131] FIG. 15 is a cross-sectional view schematically illustrating an example of a step of forming the first resin filling portion and the second resin filling portion.

[0132] In the process shown in Figure 15, a first resin filling portion 61 is formed by filling an insulating resin into a first through hole 51 in which a first through hole conductor 41 is formed, and a second resin filling portion 62 is formed by filling an insulating resin into a second through hole 52 in which a second through hole conductor 42 is formed.

[0133] 16A and 16B are cross-sectional views schematically showing an example of a step of forming a first external electrode layer and a second external electrode layer.

[0134] 16A , a plating layer 30 is formed by, for example, performing electrolytic copper plating on the surface of the sealing layer 20. Then, in the step shown in Fig. 16B , the plating layer 30 is etched so as to separate the cathode portion and the anode portion, thereby forming a first external electrode layer 31 and a second external electrode layer 32.

[0135] Through the above steps, the capacitor element 1 shown in FIG. 1 is obtained.

[0136] If through holes are previously formed in the anode plate 11 using a laser or the like and filled with insulating resin, the copper layer 12Bb may be formed on the entire surface except for the areas where the second through holes 52 are to be formed. In this case, the outer peripheral and inner conductive layers 12B can be connected by a single through-hole conductor.

[0137] Next, an example of a method for manufacturing the capacitor element 2 shown in FIG. 3 will be described as an example of a method for manufacturing the capacitor element according to the second embodiment of the present invention.

[0138] In the following, an example of a method for forming the capacitor portion 10' of the capacitor element 2 will be described, and a description of a method for forming the capacitor portion 10 will be omitted.

[0139] Although the second capacitor layer 10B of the capacitor section 10' appears not to be functional in Figure 3, by forming via conductors or through-hole conductors similar to those of the first capacitor layer 10A, it is possible to form a capacitor of a different size from the first capacitor layer 10A, or to form a second capacitor layer 10B independent of the first capacitor layer 10A.

[0140] 17A and 17B are cross-sectional views schematically illustrating an example of a step of preparing an anode plate in a first capacitor layer and a second capacitor layer, respectively.

[0141] In the steps shown in FIGS. 17A and 17B, an anode plate 11 made of a valve metal is prepared, similarly to the step shown in FIG.

[0142] 18A and 18B are cross-sectional views schematically illustrating an example of a process for filling the porous portion of a first capacitor layer with an insulating resin, respectively, and are cross-sectional views schematically illustrating an example of a process for filling the porous portion of a second capacitor layer with an insulating resin.

[0143] In the process shown in Figures 18A and 18B, similar to the process shown in Figure 6, an insulating resin such as polyimide resin is applied to a predetermined position on the top surface of the porous portion 11B, and the insulating resin is allowed to penetrate into the interior of the porous portion 11B.

[0144] 19A and 19B are cross-sectional views schematically illustrating an example of a process for forming a through groove and a through hole in a first capacitor layer and a second capacitor layer, respectively.

[0145] In the step shown in FIGS. 19A and 19B, a through groove 80 for separating the capacitor section 10 and the capacitor section 10' is formed by a laser or the like.

[0146] 19A, a through hole 50A is formed by a laser or the like in the portion where the first through-hole conductor is to be formed, and a through hole 50B is formed in the portion where the second through-hole conductor is to be formed. As shown in Fig. 19, the diameter of the through hole 50A is preferably larger than the diameter of the through hole 50B. Although the through hole 50B shown in Fig. 19 does not penetrate the anode plate 11, it is referred to as a "through hole" for convenience.

[0147] 20A and 20B are cross-sectional views schematically illustrating an example of a process for forming an inner layer of a solid electrolyte layer in a first capacitor layer and a second capacitor layer, respectively.

[0148] In the steps shown in FIGS. 20A and 20B, the inner layer 12Aa of the solid electrolyte layer is formed in the same manner as in the step shown in FIG.

[0149] 21A and 21B are cross-sectional views schematically illustrating an example of a process for forming an outer layer of a solid electrolyte layer in a first capacitor layer and a second capacitor layer, respectively.

[0150] 21A and 21B, an outer layer 12Ab of the solid electrolyte layer is formed, similarly to the step shown in Fig. 9. The inner layer 12Aa and the outer layer 12Ab form the solid electrolyte layer 12A.

[0151] Furthermore, as shown in Figures 21A and 21B, insulating resin is applied to the surface of the insulating resin that has permeated the porous portion 11B, the inside of the through groove 80, the inside of the through hole 50A, and the inside of the through hole 50B, and is then solidified.

[0152] 22A and 22B are cross-sectional views schematically illustrating an example of a process for forming a carbon layer of a conductive layer in a first capacitor layer and a second capacitor layer, respectively.

[0153] In the process shown in FIGS. 22A and 22B, a carbon layer 12Ba is formed in the same manner as in the process shown in FIG.

[0154] Furthermore, as shown in FIGS. 22A and 22B, an insulating resin is applied to the periphery of the carbon layer 12Ba and is then solidified.

[0155] 23A and 23B are cross-sectional views schematically illustrating an example of a process for forming a copper layer of a conductor layer in a first capacitor tier and a second capacitor tier, respectively.

[0156] 23A and 23B, a copper layer 12Bb is formed in the same manner as in the step shown in Fig. 11. The carbon layer 12Ba and the copper layer 12Bb form the conductor layer 12B.

[0157] 23A and 23B, an insulating resin is applied around the copper layer 12Bb and then solidified. At this time, it is preferable to adjust the height so that the copper layer 12Bb and the insulating resin are as flat as possible.

[0158] The substrate having the configuration shown in FIG. 23A constitutes the first capacitor layer 10A, and the substrate having the configuration shown in FIG. 23B constitutes the second capacitor layer 10B.

[0159] FIG. 24 is a cross-sectional view schematically illustrating an example of a process for stacking the first capacitor layer and the second capacitor layer.

[0160] In the step shown in FIG. 24, the first capacitor layer 10A and the second capacitor layer 10B are stacked together with the front and rear conductive layers 12B aligned.

[0161] 24, an insulating resin sheet such as Ajinomoto Build-up Film (ABF) is laminated on the surface of the laminate. After lamination, the laminate is placed in a mold, vacuum degassed, and then thermocompressed and cured. This forms the sealing layer 20.

[0162] FIG. 25 is a cross-sectional view schematically showing an example of a process for forming a via hole.

[0163] In the step shown in FIG. 25, the laser output is adjusted to form a first via hole 81 at a predetermined position where the insulating resin has been formed, extending to the center of the substrate where the conductive layer 12B is exposed.

[0164] Separately, a second via hole 82 is formed at a predetermined position where the insulating resin has been formed, by adjusting the laser output, up to the portion where the core portion 11A of the anode plate 11 is exposed.

[0165] Furthermore, if necessary, a third via hole 83 is formed that does not penetrate the conductive layer 12B on the front surface side of the substrate.

[0166] FIG. 26 is a cross-sectional view schematically showing an example of a process for forming first through-hole conductors, second through-hole conductors, and via conductors.

[0167] 26, the inner circumferential surface of the first via hole 81 is subjected to, for example, electroless copper plating, followed by electrolytic copper plating, thereby forming the first through-hole conductor 41.

[0168] On the other hand, the second via hole 82 is subjected to, for example, a zincate treatment, followed by nickel plating and electroless copper plating, and then electrolytic copper plating, thereby forming the second through-hole conductor 42.

[0169] Furthermore, for example, electroless copper plating is performed on the third via hole 83, and then electrolytic copper plating is performed on the third via hole 83. As a result, the via conductor 70 is formed.

[0170] FIG. 27 is a cross-sectional view schematically illustrating an example of a step of forming the first resin filling portion and the second resin filling portion.

[0171] In the process shown in Figure 27, a first resin filling portion 61 is formed by filling an insulating resin into a first via hole 81 in which a first through-hole conductor 41 is formed, and a second resin filling portion 62 is formed by filling an insulating resin into a second via hole 82 in which a second through-hole conductor 42 is formed.

[0172] 28A and 28B are cross-sectional views schematically showing an example of a step of forming a first external electrode layer and a second external electrode layer.

[0173] 28A , a plating layer 30 is formed by, for example, performing electrolytic copper plating on the surface of the sealing layer 20. Then, in the step shown in Fig. 28B , the plating layer 30 is etched so as to separate the cathode portion and the anode portion, thereby forming a first external electrode layer 31 and a second external electrode layer 32.

[0174] Through the above steps, the capacitor element 2 shown in FIG. 3 is obtained.

[0175] It is preferable that the capacitor section be cut in such a way that it is not completely cut, for example, by cutting it in the X direction and filling it with resin, and then cutting it in the Y direction and filling it with resin.

[0176] The detailed configuration of capacitor elements 1 and 2 will be described below.

[0177] 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, or a combination of these. The planar shape of the capacitor section 10 may also be an L-shape, a C-shape, a stepped shape, or the like. The same applies to the capacitor section 10′ below.

[0178] 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.

[0179] 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".

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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).

[0184] 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.

[0185] Examples of materials constituting the solid electrolyte layer 12A included in the cathode layer 12 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] The sealing layer 20 preferably contains an insulating resin.

[0196] Examples of the insulating resin contained in the sealing layer 20 include epoxy resin and phenol resin.

[0197] The sealing layer 20 preferably further contains an inorganic filler.

[0198] Examples of the inorganic filler contained in the sealing layer 20 include silica particles and alumina particles.

[0199] 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.

[0200] An insulating mask layer may be provided around the first through-hole conductor 41 or the second through-hole conductor 42 on at least one main surface of the anode plate 11. Also, an insulating mask layer 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.

[0201] The insulating mask layer is made of an insulating material, and in this case, the insulating mask layer is preferably made of an insulating resin.

[0202] Examples of insulating resins that constitute the insulating mask layer include polyphenylsulfone resins, polyethersulfone resins, cyanate ester resins, fluororesins (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, etc.), polyimide resins, polyamideimide resins, epoxy resins, and derivatives or precursors thereof.

[0203] The insulating mask layer may be made of the same resin as the sealing layer 20. Unlike the sealing layer 20, if the insulating mask layer 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 be made of a resin alone.

[0204] The insulating mask layer 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.

[0205] The insulating mask layer may be formed on the porous portion 11B either before or after the dielectric layer 13 is formed.

[0206] The first external electrode layer 31 is electrically connected to the cathode layer 12. In the example shown in Fig. 1, the first external electrode layer 31 is provided on the surface of the first through-hole conductor 41, and functions as a connection terminal of the capacitor section 10.

[0207] Examples of materials constituting the first external electrode layer 31 include metal materials containing low-resistance metals such as silver, gold, copper, etc. In this case, the first external electrode layer 31 is formed by, for example, plating the surfaces of the first through-hole conductors 41.

[0208] In order to improve the adhesion between the first external electrode layer 31 and other components, in this case, the adhesion between the first external electrode layer 31 and the first through-hole conductor 41, 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 resin may be used as the constituent material of the first external electrode layer 31.

[0209] The second external electrode layer 32 is electrically connected to the anode plate 11. In the example shown in Fig. 1 , the second external electrode layer 32 is provided on the surface of the second through-hole conductor 42, and functions as a connection terminal for the capacitor section 10. In the example shown in Fig. 1 , the second external electrode layer 32 is electrically connected to the anode plate 11 via the second through-hole conductor 42, and functions as a connection terminal for the anode plate 11.

[0210] Examples of materials constituting the second external electrode layer 32 include metal materials containing low-resistance metals such as silver, gold, copper, etc. In this case, the second external electrode layer 32 is formed by, for example, plating the surfaces of the second through-hole conductors 42.

[0211] In order to improve the adhesion between the second external electrode layer 32 and other components, in this case, the adhesion between the second external electrode layer 32 and the second through-hole conductor 42, 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 resin may be used as the constituent material of the second external electrode layer 32.

[0212] The constituent materials of the first external electrode layer 31 and the second external electrode layer 32 are preferably the same at least in terms of type, but may be different from each other.

[0213] When multiple capacitor sections are arranged in the surface direction, each of the capacitor sections may be provided with a first external electrode layer 31 electrically connected to the cathode layer 12 and a second external electrode layer 32 electrically connected to the anode plate 11, and at least one of the first external electrode layer 31 and the second external electrode layer 32 may be provided in common among the multiple capacitor sections.

[0214] The first external electrode layer 31 may be provided on both main surfaces of the sealing layer 20, or may be provided on only one main surface of the sealing layer 20. Similarly, the second external electrode layer 32 may be provided on both main surfaces of the sealing layer 20, or may be provided on only one main surface of the sealing layer 20. The first external electrode layer 31 and the second external electrode layer 32 may be provided on the same main surface of the sealing layer 20, or may be provided on different main surfaces. For example, one of the first external electrode layer 31 and the second external electrode layer 32 may be provided on both main surfaces of the sealing layer 20, and the other may be provided on only one main surface of the sealing layer 20.

[0215] When first through-hole conductor 41 is electrically connected to cathode layer 12 on the inner wall surface of first through hole 51, first through-hole conductor 41 is preferably electrically connected to the end surface of conductor layer 12B that faces the inner wall surface of first through hole 51 in the planar direction. This allows cathode layer 12 to be electrically led out via first through-hole conductor 41.

[0216] When viewed in the thickness direction, it is preferable that the first through-hole conductor 41 is electrically connected to the conductive layer 12B around the entire circumference of the first through hole 51. In this case, the connection resistance between the conductive layer 12B and the first through-hole conductor 41 is likely to decrease, and therefore the equivalent series resistance (ESR) is likely to decrease.

[0217] When the second through-hole conductor 42 is electrically connected to the anode plate 11 on the inner wall surface of the second through hole 52, the second through-hole conductor 42 is preferably electrically connected to the end surface of the anode plate 11 that faces the inner wall surface of the second through hole 52 in the planar direction. This allows the anode plate 11 to be electrically led out to the outside via the second through-hole conductor 42.

[0218] It is preferable that the core portion 11A and the porous portion 11B are exposed on the end surface of the anode plate 11 that is electrically connected to the second through-hole conductor 42. In this case, the porous portion 11B as well as the core portion 11A are electrically connected to the second through-hole conductor 42.

[0219] When viewed in the thickness direction, the second through-hole conductor 42 is preferably electrically connected to the anode plate 11 around the entire periphery of the second through hole 52. In this case, the connection resistance between the anode plate 11 and the second through-hole conductor 42 is likely to decrease, and therefore the equivalent series resistance (ESR) is likely to decrease.

[0220] The first through-hole conductor 41 is formed, for example, as follows. First, a through hole penetrating the capacitor unit 10 in the thickness direction is formed by drilling, laser processing, or the like. Next, an insulating material is filled into the through hole. The portion filled with the insulating material is then drilled, laser processing, or the like to form the first through hole 51. At this time, the diameter of the first through hole 51 is made smaller than the diameter of the through hole filled with the insulating material, thereby creating a state in the planar direction where the insulating material is present between the inner wall surface of the previously formed through hole and the inner wall surface of the first through hole 51. Then, the inner wall surface of the first through hole 51 is metallized with a metal material containing a low-resistance metal such as copper, gold, or silver, thereby forming the first through-hole conductor 41. When forming the first through-hole conductor 41, for example, metallizing the inner wall surface of the first through hole 51 by electroless copper plating, electrolytic copper plating, or the like can facilitate processing. As for the method of forming the first through-hole conductor 41, in addition to the method of metallizing the inner wall surface of the first through hole 51, a method of filling the first through hole 51 with a metal material, a composite material of metal and resin, etc. may also be used.

[0221] The second through-hole conductors 42 are formed, for example, as follows. First, second through holes 52 are formed by drilling, laser processing, or the like, penetrating the capacitor section 10 and the sealing layer 20 in the thickness direction. Then, the inner wall surfaces of the second through holes 52 are metallized with a metal material containing a low-resistance metal such as copper, gold, or silver, thereby forming the second through-hole conductors 42. When forming the second through-hole conductors 42, for example, metallizing the inner wall surfaces of the second through holes 52 with an electroless copper plating process, an electrolytic copper plating process, or the like facilitates processing. Regarding the method of forming the second through-hole conductors 42, in addition to the method of metallizing the inner wall surfaces of the second through holes 52, a method of filling the second through holes 52 with a metal material, a composite material of metal and resin, or the like may also be used.

[0222] An anode connection layer may be provided between the anode plate 11 and the second through-hole conductor 42 in the surface direction. That is, the anode plate 11 and the second through-hole conductor 42 may be electrically connected via the anode connection layer.

[0223] By providing the anode connection layer between the anode plate 11 and the second through-hole conductor 42 in the surface direction, the anode connection layer 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 functions as a barrier layer for the anode plate 11, dissolution of the anode plate 11 that occurs during chemical treatment to form external electrode layers such as the second external electrode layer 32 is suppressed, and therefore penetration of chemicals into the capacitor portion 10 is suppressed, which tends to improve reliability.

[0224] The anode connecting layer preferably includes a layer containing nickel as a main component, which reduces damage to the metal (e.g., aluminum) constituting the anode plate 11, and therefore improves the barrier properties of the anode connecting layer against the anode plate 11.

[0225] In the planar direction, an anode connection layer does not have to be provided between the anode plate 11 and the second through-hole conductor 42. In this case, the second through-hole conductor 42 may be directly connected to the end surface of the anode plate 11.

[0226] Examples of materials that can be used to form the via conductors 70 include metal materials containing low-resistance metals such as silver, gold, and copper.

[0227] The via conductor 70 is formed, for example, by plating the inner wall surface of a via 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.

[0228] 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, manufacturing conditions, and the like.

[0229] In the capacitor element of the present invention, when multiple capacitor sections are arranged in the planar direction, in at least one capacitor section, the conductive layer in the first capacitor layer that faces the second capacitor layer may be the same as the conductive layer in the second capacitor layer that faces the first capacitor layer.

[0230] In the capacitor element of the present invention, the capacitor section may include three or more capacitor layers. For example, the capacitor section may further include, in addition to the first and second capacitor layers, a third capacitor layer that faces the first capacitor layer in the thickness direction on the side opposite the second capacitor layer. In this case, the conductive layer in the first capacitor layer that faces the third capacitor layer is preferably the same as the conductive layer in the third capacitor layer that faces the first capacitor layer. Similarly, the capacitor section may further include, in addition to the first and second capacitor layers, a fourth capacitor layer that faces the second capacitor layer in the thickness direction on the side opposite the first capacitor layer. In this case, the conductive layer in the second capacitor layer that faces the fourth capacitor layer is preferably the same as the conductive layer in the fourth capacitor layer that faces the second capacitor layer.

[0231] In the capacitor element of the present invention, when a plurality of capacitor sections are arranged in the planar direction, a capacitor section including only one of the first capacitor layer and the second capacitor layer may be included.

[0232] 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 electrode layers provided on the surface of the sealing layer of the capacitor element and electrically connected to the anode plate and cathode layer of the capacitor element, respectively, and an electronic component connected to the external electrode layers.

[0233] In a composite electronic component, the electronic component connected to the external electrode layer may be a passive element or an active element. Both a passive element and an active element may be connected to the external electrode layer, or either a passive element or an active element may be connected to the external electrode layer. Also, a composite of a passive element and an active element may be connected to the external electrode layer.

[0234] 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).

[0235] 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.

[0236] 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.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] The present specification discloses the following:

[0241] <1> A capacitor element comprising: a capacitor section including a first capacitor layer and a second capacitor layer opposed to each other in a thickness direction; and a sealing layer provided so as to cover at least one main surface of the capacitor section, wherein the first capacitor layer and the second capacitor layer each include 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 the surface of the dielectric layer, wherein the cathode layer includes a solid electrolyte layer provided on the surface of the dielectric layer and a conductor layer provided on the surface of the solid electrolyte layer, and the conductor layer in the first capacitor layer opposed to the second capacitor layer is the same as the conductor layer in the second capacitor layer opposed to the first capacitor layer.

[0242] <2> The capacitor element according to <1>, further comprising a first external electrode layer provided on at least one main surface of the sealing layer so as to be electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer, wherein the first external electrode layer is arranged so as to at least partially overlap with the same conductor layer in a plan view in the thickness direction.

[0243] <3> The capacitor element described in <2>, wherein, in a planar view from the thickness direction, of the area of ​​the first external electrode layer provided on one of the main surfaces of the sealing layer, the area of ​​the first external electrode layer in a portion overlapping with the same conductor layer is 50% or more of the area of ​​the same conductor layer.

[0244] <4> The capacitor element according to <2> or <3>, further comprising a first through-hole conductor provided on at least an inner wall surface of a first through hole penetrating the capacitor portion and the sealing layer in the thickness direction, and electrically connected to the first external electrode layer, wherein the first through-hole conductor is electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer on the inner wall surface of the first through hole.

[0245] <5> The capacitor element according to <1>, further comprising: a first external electrode layer provided on at least one main surface of the sealing layer so as to be electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer; and a second external electrode layer provided on at least one main surface of the sealing layer so as to be electrically connected to the anode plate of the first capacitor layer and the anode plate of the second capacitor layer, wherein at least one of the first external electrode layer and the second external electrode layer is arranged to at least partially overlap with the same conductor layer in a planar view in the thickness direction.

[0246] <6> The capacitor element described in <5>, wherein, in a planar view from the thickness direction, the total area of ​​all of the first external electrode layers and the second external electrode layers provided on either main surface of the sealing layer is 50% or more of the area surrounded by the outer peripheral edge of the sealing layer.

[0247] <7> The capacitor element according to <5> or <6>, further comprising: a first through-hole conductor provided on at least an inner wall surface of a first through hole penetrating the capacitor portion and the sealing layer in the thickness direction, and electrically connected to the first external electrode layer; and a second through-hole conductor provided on at least an inner wall surface of a second through hole penetrating the capacitor portion and the sealing layer in the thickness direction, and electrically connected to the second external electrode layer, wherein the first through-hole conductor is electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer on the inner wall surface of the first through hole, and the second through-hole conductor is electrically connected to the anode plate of the first capacitor layer and the anode plate of the second capacitor layer on the inner wall surface of the second through hole.

[0248] <8> The capacitor element according to any one of <1> to <7>, wherein the areas of the capacitance parts of the first capacitor layer and the second capacitor layer are different.

[0249] REFERENCE SIGNS LIST 1, 2 Capacitor element 10, 10' Capacitor portion 10A First capacitor layer 10B Second capacitor layer 11 Anode plate 11A Core portion 11B Porous portion 12 Cathode layer 12A Solid electrolyte layer 12Aa Inner layer of solid electrolyte layer 12Ab Outer layer of solid electrolyte layer 12B Conductor layer 12Ba Carbon layer 12Bb Copper layer 13 Dielectric layer 20 Sealing layer 30 Plating layer 31 First external electrode layer 32 Second external electrode layer 41 First through-hole conductor 42 Second through-hole conductor 50A, 50B Through hole 51 First through-hole 52 Second through-hole 61 First resin-filled portion 62 Second resin-filled portion 70 Via conductor 80 Through groove 81 First via hole 82 Second via hole 83 Third via hole

Claims

1. A capacitor element comprising: a capacitor section including a first capacitor layer and a second capacitor layer opposed to each other in a thickness direction; and a sealing layer provided so as to cover at least one main surface of the capacitor section, wherein the first capacitor layer and the second capacitor layer each include 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, wherein the cathode layer includes a solid electrolyte layer provided on the surface of the dielectric layer and a conductor layer provided on the surface of the solid electrolyte layer, and the conductor layer in the first capacitor layer opposed to the second capacitor layer is the same as the conductor layer in the second capacitor layer opposed to the first capacitor layer.

2. A capacitor element as described in claim 1, further comprising a first external electrode layer provided on at least one main surface of the sealing layer so as to be electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer, wherein, when viewed in a plan view from the thickness direction, the first external electrode layer is arranged so as to overlap at least a portion of the same conductor layer.

3. A capacitor element as described in claim 2, wherein, when viewed in a plane from the thickness direction, the area of ​​the first external electrode layer provided on either one of the main surfaces of the sealing layer, of the portion overlapping with the same conductive layer, is 50% or more of the area of ​​the same conductive layer.

4. A capacitor element as described in claim 2 or 3, further comprising a first through-hole conductor provided on at least the inner wall surface of a first through hole penetrating the capacitor portion and the sealing layer in the thickness direction and electrically connected to the first external electrode layer, wherein the first through-hole conductor is electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer on the inner wall surface of the first through hole.

5. A capacitor element as described in claim 1, further comprising: a first external electrode layer provided on at least one main surface of the sealing layer so as to be electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer; and a second external electrode layer provided on at least one main surface of the sealing layer so as to be electrically connected to the anode plate of the first capacitor layer and the anode plate of the second capacitor layer, wherein at least one of the first external electrode layer and the second external electrode layer is arranged to at least partially overlap the same conductor layer when viewed in a planar view in the thickness direction.

6. A capacitor element as described in claim 5, wherein, when viewed in a plane from the thickness direction, the total area of ​​all of the first external electrode layers and the second external electrode layers provided on either one of the main surfaces of the sealing layer is 50% or more of the area surrounded by the outer peripheral edge of the sealing layer.

7. A capacitor element as described in claim 5 or 6, further comprising: a first through-hole conductor provided on at least the inner wall surface of a first through hole penetrating the capacitor portion and the sealing layer in the thickness direction, and electrically connected to the first external electrode layer; and a second through-hole conductor provided on at least the inner wall surface of a second through hole penetrating the capacitor portion and the sealing layer in the thickness direction, and electrically connected to the second external electrode layer, wherein the first through-hole conductor is electrically connected to the cathode layer of the first capacitor layer and the cathode layer of the second capacitor layer at the inner wall surface of the first through hole, and the second through-hole conductor is electrically connected to the anode plate of the first capacitor layer and the anode plate of the second capacitor layer at the inner wall surface of the second through hole.

8. The capacitor element according to any one of claims 1 to 7, wherein the areas of the capacitive portions of the first capacitor layer and the second capacitor layer are different.

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