Capacitor element

Abstract

A capacitor element 1 comprises a positive electrode plate 10 that has a porous layer 12 on at least one main surface, a dielectric layer 20 that is provided on the surface of the porous layer 12, a negative electrode layer 30 that is provided on the surface of the dielectric layer 20, and an insulation layer 40 that is provided on the surface of the dielectric layer 20 so as to partially overlap the negative electrode layer 30, the relationship d1≥0.2×d2 being satisfied, where d1 is the layer thickness of a portion 34 of the insulation layer 40 where the negative electrode layer 30 and the insulation layer 40 overlap at an end 40a that overlaps the negative electrode layer 30, and d2 is the layer thickness of the insulation layer.

Description

Capacitor element

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

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

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

[0004] For example, in Figure 27 of Patent Document 1, if there is a difference in layer thickness between the conductive layer portion (cathode layer 24) and the insulating layer portion (stress relaxation layer 13, insulating layer 30) and the transition portion between them, the pressure applied to each layer when a resin sheet is attached to form a sealing layer will be uneven, which may reduce the interfacial adhesion between the thin layer, i.e., the transition portion, and the sealing layer. As a result, peeling called delamination, for example, peeling of the sealing layer, may occur.

[0005] The present invention has been made to solve the above problems, and aims to provide a capacitor element that can improve the interfacial adhesion between the sealing layer and its underlying layer and suppress delamination.

[0006] The capacitor element of the present invention comprises an anode plate having a porous layer on at least one main surface thereof, a dielectric layer provided on the surface of the porous layer, a cathode layer provided on the surface of the dielectric layer, and an insulating layer provided on the surface of the dielectric layer so as to partially overlap the cathode layer, wherein d1 is the thickness of an overlapping portion of the cathode layer and the insulating layer at the end of the insulating layer overlapping the cathode layer, and d2 is the thickness of the insulating layer, and d1≧0.2×d2 is satisfied.

[0007] According to the present invention, it is possible to provide a capacitor element that can improve the interfacial adhesion between the sealing layer and its underlying layer and suppress delamination.

[0008] FIG. 1 is a cross-sectional schematic diagram showing an example of a capacitor element according to a first embodiment of the present invention. FIG. 2 is an enlarged schematic diagram showing an example of a region surrounded by a dashed line in the capacitor element shown in FIG. 1. FIG. 3 is an enlarged schematic diagram showing another example of a region surrounded by a dashed line in the capacitor element shown in FIG. 1. FIG. 4 is a plan view schematic diagram showing an example of a capacitor array according to a second embodiment of the present invention. FIG. 5 is a cross-sectional schematic diagram showing an example of a cross section taken along line A-A of the capacitor array shown in FIG. 4. FIG. 6 is a cross-sectional schematic diagram showing an example of a cross section taken along line B-B of the capacitor array shown in FIG. 4. FIG. 7 is a plan view schematic diagram showing an example of a capacitor array according to a third embodiment of the present invention. FIG. 8 is a cross-sectional schematic diagram showing an example of a cross section taken along line A-A of the capacitor array shown in FIG. 7. FIG. 9 is a cross-sectional schematic diagram showing an example of a cross section taken along line B-B of the capacitor array shown in FIG. 7.

[0009] 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.

[0010] 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.

[0011] 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."

[0012] 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.

[0013] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0014] [Embodiment 1]

[0015] FIG. 1 is a cross-sectional view schematically illustrating an example of a capacitor element according to a first embodiment of the present invention.

[0016] The capacitor element 1 shown in FIG. 1 includes an anode plate 10 , a dielectric layer 20 , a cathode layer 30 , and an insulating layer 40 .

[0017] The anode plate 10 has a core 11 and a porous layer 12 .

[0018] In this specification, the term "plate" also includes "sheet," "foil," "film," etc., and these are not distinguished by thickness.

[0019] The core 11 is made of a metal, and preferably made of a valve metal. When the core 11 is made of a valve metal, the anode plate 10 is also called a valve metal substrate.

[0020] Examples of valve metals include simple metals such as aluminum, tantalum, niobium, titanium, and zirconium, and alloys containing at least one of these simple metals. Among these, aluminum or an aluminum alloy is preferred.

[0021] The porous layer 12 is provided on at least one main surface of the core 11. That is, the porous layer 12 may be provided on only one main surface of the core 11, or may be provided on both main surfaces of the core 11 as shown in Fig. 1. In this way, the anode plate 10 has the porous layer 12 on at least one main surface. This increases the surface area of ​​the anode plate 10, which makes it easier to improve the capacitance of the capacitor element 1.

[0022] The porous layer 12 is preferably an etching layer formed by etching the surface of the anode plate 10 .

[0023] The shape of the anode plate 10 is preferably a flat plate, and more preferably a foil. Thus, in this specification, the term "plate" also includes "foil." Furthermore, in this specification, the term "plate" also includes "sheet," "film," and the like.

[0024] The dielectric layer 20 is provided on the surface of the porous layer 12. Although the drawing shows a simplified representation, more specifically, the dielectric layer 20 is provided along the surface (outline) of each pore present in the porous layer 12.

[0025] The dielectric layer 20 is preferably made of an oxide film of the valve metal described above. For example, when the anode plate 10 is made of aluminum foil, the oxide film that becomes the dielectric layer 20 is formed by anodizing the anode plate 10 in an aqueous solution containing ammonium adipate or the like (also called chemical conversion treatment). Since the dielectric layer 20 is formed along the surface of the porous layer 12, pores (recesses) are provided in the dielectric layer 20.

[0026] The cathode layer 30 is provided on the surface of the dielectric layer 20. More specifically, the cathode layer 30 is provided on the surface of the dielectric layer 20 in a region surrounded by the insulating layer 40.

[0027] 1, the cathode layer 30 includes a solid electrolyte layer 31 provided on the surface of the dielectric layer 20, and a conductor layer 32 provided on the surface of the solid electrolyte layer 31. When the cathode layer 30 includes the solid electrolyte layer 31, the capacitor element constitutes a solid electrolytic capacitor.

[0028] Examples of materials constituting the solid electrolyte layer 31 include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene) (PEDOT) is particularly preferred. The conductive polymer may also contain a dopant such as polystyrene sulfonate (PSS).

[0029] The solid electrolyte layer 31 is formed in a predetermined region including the inside of the pores of the dielectric layer 20 by, for example, a method of applying a dispersion of a conductive polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric layer 20 and drying it, or a method of forming a polymerized film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 20 using a treatment liquid containing a polymerizable monomer such as 3,4-ethylenedioxythiophene.

[0030] The conductive layer 32 preferably includes a metal layer containing a metal filler.

[0031] The metal filler is preferably at least one selected from the group consisting of a copper filler, a silver filler, and a nickel filler.

[0032] The metal layer may be, for example, a metal plating film, a metal foil, etc. In this case, the metal layer is preferably made of at least one metal selected from the group consisting of copper, silver, nickel, and alloys containing at least one of these metals as a main component.

[0033] In this specification, the term "major component" means the element component that occupies the largest weight ratio.

[0034] The conductive layer 32 preferably further includes a conductive resin layer in addition to the metal layer.

[0035] The conductive resin layer may be, for example, a conductive adhesive layer containing at least one conductive filler selected from the group consisting of copper filler, silver filler, nickel filler, and carbon filler.

[0036] The conductive layer 32 may include only a metal layer, may include only a conductive resin layer, or may include both a metal layer and a conductive resin layer.

[0037] 1 , the conductor layer 32 includes a first conductor layer 32A provided on the surface of the solid electrolyte layer 31 and a second conductor layer 32B provided on the surface of the first conductor layer 32A. In this way, the conductor layer 32 preferably includes a plurality of types of conductor layers.

[0038] In solid electrolytic capacitors, leakage current is likely to be a problem due to the small thickness of the dielectric layer. In contrast, since the conductive layer 32 includes multiple types of conductive layers, such as the first conductive layer 32A and the second conductive layer 32B, multiple bulk resistances and interface resistances exist in the cathode layer 30, making it easier to suppress leakage current.

[0039] The first conductive layer 32A is preferably a conductive resin layer containing a conductive filler.

[0040] The second conductive layer 32B is preferably a metal layer containing a metal filler.

[0041] The conductive layer 32 may include, for example, a carbon layer as the first conductive layer 32A and a copper layer as the second conductive layer 32B.

[0042] The carbon layer is formed in a predetermined region by, for example, applying a carbon paste containing a carbon filler to the surface of the solid electrolyte layer 31 by a sponge transfer method, a screen printing method, a dispenser coating method, an inkjet printing method, or the like.

[0043] The copper layer is formed in a predetermined region by applying a copper paste containing a copper filler to the surface of the carbon layer by a sponge transfer method, a screen printing method, a spray coating method, a dispenser coating method, an inkjet printing method, or the like.

[0044] The planar shape of the outer peripheral edge of each layer of the cathode layer 30 when viewed from the thickness direction is, for example, a quadrilateral (square), but the planar shape of the outer peripheral edge of each layer of the cathode layer 30 may be a rectangular shape that is a quadrilateral shape other than a square, or may be another shape such as a polygonal shape other than a quadrilateral, a circle, or an ellipse.

[0045] In this specification, the thickness direction means the thickness direction of the capacitor element, and is defined as the up-down direction in FIG. 1, for example.

[0046] In the capacitor element 1, the anode plate 10, the dielectric layer 20, and the cathode layer 30 form a capacitor section.

[0047] The insulating layer 40 is made of an insulating material.

[0048] Examples of insulating materials that can be used to form the insulating layer 40 include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinylether copolymer, etc.), a composition consisting of soluble polyimidesiloxane and epoxy resin, polyimide resin, polyamideimide resin, derivatives or precursors of these, etc.

[0049] The insulating layer 40 is provided on the surface of the dielectric layer 20. The insulating layer 40 is provided so as to partially overlap the cathode layer 30. The insulating layer 40 is also provided on the periphery of the cathode layer 30.

[0050] In FIG. 1 , the insulating layer 40 includes a first insulating layer 40A provided on the surface of the dielectric layer 20 in a region surrounding the solid electrolyte layer 31, and a second insulating layer 40B provided on the surface of the first insulating layer 40A, with the second insulating layer 40B being provided so as to partially overlap the solid electrolyte layer 31.

[0051] FIG. 2 is an enlarged schematic view of an example of the region surrounded by the dashed line of the capacitor element shown in FIG.

[0052] As shown in Figures 1 and 2, when the thickness of the overlapping portion 34 of the cathode layer 30 and the insulating layer 40 at the end 40a of the insulating layer 40 overlapping the cathode layer 30 is d1 and the thickness of the insulating layer 40 is d2, the capacitor element 1 satisfies d1 ≥ 0.2 × d2. This reduces the difference in thickness between the cathode layer 30 and the insulating layer 40 and their transition portion (overlapping portion 34). This allows for uniform pressure to be applied to each layer when forming the sealing layer 50, for example by attaching a resin sheet, thereby improving the interfacial adhesion between the sealing layer 50 and the underlying layers after formation. As a result, delamination, e.g., peeling of the sealing layer 50, can be suppressed.

[0053] 2 , the overlapping portion 34 at the end 40a of the insulating layer 40 is preferably composed of at least one of the solid electrolyte layer 31 and the carbon layer serving as the first conductor layer 32A, and the insulating layer 40. By overlapping the insulating layer 40 with at least one of the solid electrolyte layer 31 and the carbon layer serving as the first conductor layer 32A in the thinnest portion of the transition between the cathode layer 30 and the insulating layer 40, it is possible to effectively increase the film thickness of the overlapping portion 34, which tends to become thin during molding. This makes it possible to make the pressure applied during the formation of the sealing layer 50 more uniform, and to further improve the interfacial adhesion between the sealing layer 50 and each underlying layer after the sealing layer 50 is formed.

[0054] 2 , the overlapping portion 34 at the end 40 a of the insulating layer 40 may be composed of only the solid electrolyte layer 31 and the insulating layer 40. In this case, the layer thickness d1 corresponds to the thickness of the solid electrolyte layer 31 at the end 40 a of the insulating layer 40.

[0055] FIG. 3 is a schematic diagram showing an enlarged view of another example of the region surrounded by the dashed line of the capacitor element shown in FIG.

[0056] 3 , the overlapping portion 34 at the end 40 a of the insulating layer 40 may be composed of only the solid electrolyte layer 31, the carbon layer serving as the first conductor layer 32A, and the insulating layer 40. In this case, the layer thickness d1 corresponds to the combined layer thickness of the solid electrolyte layer 31 and the carbon layer (first conductor layer 32A) at the end 40 a of the insulating layer 40.

[0057] The end 40a of the insulating layer 40 may be the end of the first insulating layer 40A, or may be the end of the second insulating layer 40B as shown in Figures 2 and 3. Note that the "end of the insulating layer" refers to the point where the insulating layer almost disappears, as shown in Figures 2 and 3.

[0058] Capacitor element 1 preferably satisfies d1≧0.2×d2, and more preferably satisfies d1≧0.5×d2.

[0059] It is preferable that the capacitor element 1 satisfy d1≦d2. Conversely, if d1>d2, when the capacitor element 1 is sealed with the sealing layer 50, the insulating layer 40 will be lower than the cathode layer 30, which may cause the sealing material, which is the material of the sealing layer 50, to flow into the dividing portions 61 and 62 described below, thereby reducing the adhesion between the insulating layer 40 and the sealing layer 50 near the dividing portions 61 and 62. On the other hand, if d1≦d2 is satisfied, it is possible to reduce the amount of sealing material that flows into the dividing portions 61 and 62, thereby preventing a reduction in the adhesion between the insulating layer 40 and the sealing layer 50 near the dividing portions 61 and 62. Furthermore, the difference in height between d1 and d2 can increase the number of irregularities, thereby improving the mechanical anchoring effect.

[0060] Capacitor element 1 preferably satisfies d1 ≥ 2 μm, and more preferably d1 ≥ 5 μm. By satisfying d1 ≥ 2 μm, even when capacitor element 1 is miniaturized, it is possible to ensure a minimum layer thickness at overlapping portion 34 and ensure interfacial adhesion.

[0061] Capacitor element 1 preferably satisfies d1≦100 μm, and more preferably d1≦40 μm. By satisfying d1≦100 μm, it is possible to provide a structure that ensures adhesion between sealing layer 50 and the thinnest part of the transition portion between cathode layer 30 and insulating layer 40, even when capacitor element 1 is made smaller or larger.

[0062] From the same viewpoint, the insulating layer 40 preferably satisfies 10 μm≦d2≦500 μm, and more preferably satisfies 25 μm≦d2≦200 μm.

[0063] From the same viewpoint, when the thickness of the cathode layer 30 is d3, the cathode layer 30 preferably satisfies 10 μm≦d3≦500 μm, and more preferably satisfies 25 μm≦d3≦200 μm.

[0064] In the capacitor element of the present invention, the characteristics regarding the layer thicknesses d1, d2, and d3 described above need only be satisfied at at least one location in a cross section parallel to the thickness direction, but if there are multiple locations in the cross section that can satisfy the above characteristics, it is preferable that they be satisfied at all locations.

[0065] In the capacitor element of the present invention, the thickness d2 of the insulating layer means the thickness of the insulating layer itself constituting the overlapping portion that is the measurement target of the thickness d1 in a cross section parallel to the thickness direction. That is, in the cross section, the portion that is the measurement target of the thickness d1 is adjacent to the portion that is the measurement target of the thickness d2.

[0066] The insulating layer 40 is formed, for example, by applying an insulating material to the surface of the dielectric layer 20 that overlaps the periphery of the solid electrolyte layer 31, so that the periphery of the solid electrolyte layer 31 surrounds the formation area or planned formation area of ​​the conductor layer 32.

[0067] Examples of insulating materials constituting the first insulating layer 40A and the second insulating layer 40B include polyphenylsulfone, polyethersulfone, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), a composition consisting of soluble polyimide siloxane and epoxy resin, polyimide resin, polyamideimide resin, derivatives or precursors of these, etc.

[0068] The insulating material constituting the first insulating layer 40A may be the same as or different from the insulating material constituting the second insulating layer 40B.

[0069] The first insulating layer 40A may be made of the same resin as the sealing layer 50 described below. Unlike the sealing layer 50, if the first insulating layer 40A contains an inorganic filler, this may adversely affect the active portion of the capacitor element 1. Therefore, the first insulating layer 40A is preferably made of a resin alone.

[0070] The thickness of the first insulating layer 40A may be the same as the thickness of the second insulating layer 40B, may be greater than the thickness of the second insulating layer 40B, or may be smaller than the thickness of the second insulating layer 40B.

[0071] The thickness of the first insulating layer 40A may be the same as the thickness of the solid electrolyte layer 31, may be greater than the thickness of the solid electrolyte layer 31, or may be smaller than the thickness of the solid electrolyte layer 31.

[0072] The thickness of the second insulating layer 40B may be the same as the thickness of the conductive layer 32, may be greater than the thickness of the conductive layer 32, or may be smaller than the thickness of the conductive layer 32.

[0073] In the example shown in FIG. 1, the insulating layer 40 includes a first insulating layer 40A and a second insulating layer 40B, but the insulating layer 40 may include other layers in addition to the first insulating layer 40A and the second insulating layer 40B.

[0074] The capacitor element 1 preferably further includes a sealing layer 50 .

[0075] The sealing layer 50 contains a resin material.

[0076] Examples of the resin material contained in the sealing layer 50 include epoxy resin, phenol resin, and polyimide resin.

[0077] The sealing layer 50 may further contain an inorganic filler such as silica or alumina in addition to the resin material.

[0078] The sealing layer 50 may be made up of only one layer, or may be made up of two or more layers.

[0079] The sealing layer 50 covers the insulating layer 40 and the cathode layer 30 .

[0080] In capacitor element 1, deformation due to external forces is suppressed by providing sealing layer 50 that covers insulating layer 40 and cathode layer 30, and therefore, the occurrence of delamination is further suppressed. By providing a sealing layer that contains a resin material and covers the insulating layer and cathode layer in the capacitor element, deformation due to external forces is suppressed, and therefore, the occurrence of delamination is further suppressed.

[0081] The sealing layer 50 may be provided so that a part of the anode plate 10, in particular the end face of the core 11, is exposed from the sealing layer 50. In this case, even if the sealing layer 50 is provided, the anode plate 10 can be connected to the outside of the sealing layer 50.

[0082] The sealing layer 50 is formed in a predetermined region by, for example, attaching a resin sheet to cover the cathode layer 30, or applying a resin paste to cover the cathode layer 30, or the like.

[0083] The capacitor element 1 is manufactured, for example, by the following method.

[0084] First, an anode plate 10 having a porous layer 12 on both main surfaces of a core 11, i.e., an anode plate 10 having a porous layer 12 on both main surfaces, is prepared. Then, an anodization treatment is performed on the anode plate 10, thereby forming an oxide film that will become the dielectric layer 20 on the surface of the porous layer 12.

[0085] Next, an insulating material is applied to the surface of the dielectric layer 20 to form the first insulating layer 40A so as to surround the region where the solid electrolyte layer 31 is to be formed.

[0086] Then, in the region surrounded by the first insulating layer 40A, a dispersion liquid of a conductive polymer is applied to the surface of the dielectric layer 20 and dried, and this process is repeated multiple times to form the solid electrolyte layer 31.

[0087] Next, an insulating material is applied to the surface of the first insulating layer 40A to form the second insulating layer 40B so as to cover the entire end of the solid electrolyte layer 31 when viewed in a plan view from the thickness direction.

[0088] Next, a conductive paste containing a conductive filler is applied to the surface of the solid electrolyte layer 31 to form a first conductive layer 32A on the surface of the solid electrolyte layer 31. After that, a metal paste containing a metal filler is applied to the surface of the first conductive layer 32A to form a second conductive layer 32B on the surface of the first conductive layer 32A. In this manner, the conductive layer 32 including the first conductive layer 32A and the second conductive layer 32B is formed. In this manner, a solid electrolytic capacitor sheet is obtained.

[0089] Next, resin sheets are attached to both main surfaces of the solid electrolytic capacitor sheet to form sealing layers 50 that cover the conductive layers 32, thereby producing the capacitor element 1.

[0090] [Embodiment 2] Fig. 4 is a plan view schematic diagram showing an example of a capacitor array according to embodiment 2 of the present invention. Fig. 5 is a cross-sectional view schematic diagram showing an example of a cross section taken along line A-A of the capacitor array shown in Fig. 4. Fig. 6 is a cross-sectional view schematic diagram showing an example of a cross section taken along line B-B of the capacitor array shown in Fig. 4.

[0091] The capacitor array 101 shown in Figures 4 to 6 has a plurality of capacitor elements 1 shown in Figure 1. In the example shown in Figures 4 to 6, the capacitor array 101 has four capacitor elements 1.

[0092] In the capacitor array 101 in which multiple capacitor elements 1 are arranged in an array, deformation due to external forces is suppressed, and delamination between multiple layers of different materials, particularly delamination between the porous layer 12 and the solid electrolyte layer 31, is less likely to occur.

[0093] Furthermore, by arranging a plurality of capacitor elements 1 in an array to form the capacitor array 101, it is possible to provide a multi-channel capacitor array in which the capacitance and position are optimized to meet market demands.

[0094] Furthermore, by using the capacitor array 101 in which a plurality of capacitor elements 1 are arranged in an array, the plurality of capacitor elements 1 can be efficiently mounted on the substrate.

[0095] The plurality of capacitor elements 1 may be arranged in a plane or in a line.

[0096] The plurality of capacitor elements 1 may be arranged regularly or irregularly.

[0097] The areas of the plurality of capacitor elements 1 when viewed in the thickness direction may be the same as each other, may be different from each other, or may be partially different.

[0098] The planar shapes of the plurality of capacitor elements 1 when viewed in the thickness direction may be the same as each other, may be different from each other, or may be partially different from each other.

[0099] The capacitor array 101 preferably has a sealing portion 60 .

[0100] Sealing section 60 seals the plurality of capacitor sections from both main surfaces that face each other in the thickness direction of the plurality of capacitor sections, thereby protecting the plurality of capacitor sections with sealing section 60.

[0101] The sealing portion 60 is made of an insulating material, that is, the sealing portion 60 functions as an insulating portion.

[0102] The sealing portion 60 is formed by stacking a plurality of sealing layers in the thickness direction.

[0103] The multiple sealing layers constituting the sealing unit 60 include a first sealing layer 60A and a second sealing layer 60B. In the example shown in Fig. 5 etc., the sealing unit 60 is formed by stacking the first sealing layer 60A and the second sealing layer 60B in the thickness direction in that order from the capacitor unit side. That is, in the example shown in Fig. 5 etc., the second sealing layer 60B is adjacent to the first sealing layer 60A on the side opposite the capacitor unit.

[0104] The sealing portion 60 only needs to include at least the first sealing layer 60A and the second sealing layer 60B, and may further include at least one sealing layer between the first sealing layer 60A and the second sealing layer 60B.

[0105] The insulating material forming first sealing layer 60A may contain an insulating resin.

[0106] Examples of insulating resins contained in the insulating material that forms the first sealing layer 60A include epoxy resin, phenol resin, and polyimide resin.

[0107] The insulating material that forms first sealing layer 60A may further contain an inorganic filler.

[0108] Examples of inorganic fillers contained in the insulating material that forms first sealing layer 60A include silica fillers and alumina fillers.

[0109] The first sealing layer 60A is formed so as to seal the capacitor section from both main surfaces of the capacitor section, for example, by a method of thermocompressing an insulating resin sheet or a method of applying an insulating resin paste and then thermally curing it.

[0110] The insulating material forming second sealing layer 60B may contain an insulating resin.

[0111] Examples of insulating resins contained in the insulating material constituting the second sealing layer 60B include epoxy resin, phenol resin, and polyimide resin.

[0112] The insulating materials constituting the first sealing layer 60A and the second sealing layer 60B preferably contain different insulating resins.

[0113] The insulating materials constituting the first sealing layer 60A and the second sealing layer 60B may contain the same insulating resin.

[0114] The insulating material forming second sealing layer 60B may further contain an inorganic filler.

[0115] Examples of inorganic fillers contained in the insulating material that forms second sealing layer 60B include silica fillers and alumina fillers.

[0116] The inorganic fillers contained in the insulating materials constituting first sealing layer 60A and second sealing layer 60B may be the same or different from each other at least in terms of type.

[0117] In first sealing layer 60A and second sealing layer 60B, the proportion of the inorganic filler content relative to the total amount of insulating material may be the same as or different from each other.

[0118] For example, after the first sealing layer 60A is formed by the above-described method, the second sealing layer 60B is formed adjacent to the first sealing layer 60A on the side opposite the capacitor portion by thermocompression bonding an insulating resin sheet, applying an insulating resin paste and then thermally curing it, or the like. When the second sealing layer 60B is formed on the first sealing layer 60A by a build-up method in this manner, there is no need to soften the already formed first sealing layer 60A by heat treatment when forming the second sealing layer 60B. Therefore, when the second sealing layer 60B is formed, the first sealing layer 60A and the second sealing layer 60B are not integrated, and an interface exists between the first sealing layer 60A and the second sealing layer 60B.

[0119] The sealing portion 60 is filled between the plurality of capacitor elements 1, in this case, between the four capacitor elements 1 as well.

[0120] More specifically, first sealing layer 60A also fills dividing portions 61 that divide multiple capacitor elements 1 in the vertical direction in Fig. 4. First sealing layer 60A also fills through holes 80 for through-hole conductors that are electrically connected to cathode layer 30, which will be described later.

[0121] Second sealing layer 60B is also filled in dividing portions 62 that divide a plurality of capacitor elements 1 in the horizontal direction in FIG.

[0122] [Embodiment 3] Fig. 7 is a plan view schematic diagram showing an example of a capacitor array according to embodiment 3 of the present invention. Fig. 8 is a cross-sectional view schematic diagram showing an example of a cross section taken along line A-A of the capacitor array shown in Fig. 7. Fig. 9 is a cross-sectional view schematic diagram showing an example of a cross section taken along line B-B of the capacitor array shown in Fig. 7.

[0123] The capacitor array 102 shown in FIGS. 7 to 9 is different from the capacitor array 101 shown in FIGS. 4 to 6 in that it further includes via conductors 70, external electrode layers 71 and 72, and through-hole conductors 80A and 80B.

[0124] 8 and 9, thickness d2 is preferably the film thickness of insulating layer 40 around through-hole conductor 80A or 80B. The overlapping portions (thickness d1) of cathode layer 30 and insulating layer 40 may exist around through-hole conductors 80A and 80B or around dividing portions 61 and 62. However, by satisfying d1≧0.2×d2 in the areas around through-hole conductors 80A and 80B where delamination is more likely to occur, a greater delamination suppression effect can be achieved.

[0125] The via conductors 70 are provided in the thickness direction so as to extend from the surface of the sealing portion 60 to the cathode layer 30, more specifically, so as to extend from the surface of the sealing portion 60 to the second conductive layer 32B. This allows the cathode layer 30 to be electrically led out of the sealing portion 60 through the via conductors 70 and to be electrically connected to the outside of the sealing portion 60.

[0126] The via conductor 70 is connected to an external electrode layer 71 provided on the surface of the sealing portion 60 .

[0127] Examples of materials that can be used to form the via conductors 70 include low-resistance metals such as silver, gold, and copper.

[0128] The via conductors 70 are formed, for example, as follows: First, holes are formed in the sealing portion 60 by drilling, laser processing, or the like, so as to extend from the surface of the sealing portion 60 to the cathode layer 30 in the thickness direction, in this case extending from the surface of the sealing portion 60 to the second conductor layer 32B. Then, the via conductors 70 are formed by plating the inner wall surfaces of the holes formed in the sealing layer 50 or by filling the holes with a conductive paste and then performing a heat treatment.

[0129] The through-hole conductors 80A and 80B penetrate the sealing portion 60 in the thickness direction. In the example shown in Fig. 8 etc., the through-hole conductors 80A and 80B penetrate the sealing portion 60 as well as the anode plate 10 (core portion 11), the dielectric layer 20 and the insulating layer 40 in the thickness direction.

[0130] The through-hole conductors that penetrate the sealing portion 60 in the thickness direction are provided, thereby imparting electrical functionality to the sealing portion 60 .

[0131] The through-hole conductor 80A is preferably provided on at least the inner wall surface of the through hole 81A that penetrates the sealing portion 60 in the thickness direction. In the example shown in Fig. 8 etc., the through-hole conductor 80A is provided on the inner wall surface of the through hole 81A, rather than filling the entire interior of the through hole 81A.

[0132] The through-hole conductor 80A is electrically insulated from the anode plate 10. As shown in Figures 8 and 9, it is preferable that an insulating material such as a sealing portion 60 is filled between the through-hole conductor 80A and the anode plate 10.

[0133] The through-hole conductor 80A is connected to the external electrode layer 71 provided on the surface of the sealing portion 60. Therefore, the through-hole conductor 80A is electrically connected to the cathode layer 30 via the external electrode layer 71 and the via conductor 70.

[0134] The through-hole conductor 80B is preferably provided on at least the inner wall surface of the through hole 81B that penetrates the sealing portion 60 in the thickness direction. In the example shown in Fig. 8 etc., the through-hole conductor 80B is provided on the inner wall surface of the through hole 81B, rather than filling the entire interior of the through hole 81B.

[0135] The through-hole conductor 80B is electrically connected to the anode plate 10. As shown in FIGS. 8 and 9 , the through-hole conductor 80B is preferably electrically connected to the anode plate 10 at the inner wall surface of the through hole 81B. More specifically, the through-hole conductor 80B is preferably electrically connected to the end surface of the anode plate 10 that faces the inner wall surface of the through hole 81B in a direction perpendicular to the thickness direction. In the example shown in FIG. 8 and other figures, the through-hole conductor 80B is connected to the end surface of the anode plate 10, particularly the end surface of the core portion 11. This allows the anode plate 10 to be electrically led out via the through-hole conductor 80B. In other words, the sealing portion 60 is provided with the electrical function of electrically leading the anode plate 10 out. The through-hole conductor 80B is then connected to the external electrode layer 72 provided on the surface of the sealing portion 60.

[0136] When viewed from the thickness direction, it is preferable that through-hole conductor 80B is electrically connected to anode plate 10 along the entire periphery of through hole 81B. This tends to reduce the connection resistance between through-hole conductor 80B and anode plate 10, and therefore tends to reduce the equivalent series resistance of capacitor element 1.

[0137] The through-hole conductor 80A is formed, for example, as follows. First, a through-hole penetrating the anode plate 10 (core 11), the dielectric layer 20, and the insulating layer 40 in the thickness direction is formed by drilling, laser processing, or the like. Next, the sealing portion 60 is formed, and an insulating material is filled into the through-hole. The portion filled with the insulating material is then drilled, laser processed, or the like to form a through-hole 81A penetrating the sealing portion 60 in the thickness direction. At this time, the diameter of the through-hole 81A 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 exists between the inner wall surface of the previously formed through-hole and the inner wall surface of the through-hole 81A. The through-hole conductor 80A is then formed by metallizing the inner wall surface of the through-hole 81A with a low-resistance metal such as copper, gold, or silver. When forming the through-hole conductor 80A, for example, metallizing the inner wall surface of the through-hole 81A by electroless copper plating, electrolytic copper plating, or the like facilitates processing. As a method for forming the through-hole conductor 80A, in addition to a method of metallizing the inner wall surface of the through-hole 81A, a method of filling the through-hole 81A with a metal, a composite material of metal and resin, or the like may be used.

[0138] The through-hole conductor 80B is formed, for example, as follows. First, a through-hole 81B is formed by drilling, laser processing, or the like, penetrating the sealing portion 60, the anode plate 10 (core portion 11), the dielectric layer 20, and the insulating layer 40 in the thickness direction. The inner wall surface of the through-hole 81B is then metallized with a low-resistance metal such as copper, gold, or silver, thereby forming the through-hole conductor 80B. When forming the through-hole conductor 80B, for example, metallizing the inner wall surface of the through-hole 81B with an electroless copper plating process, an electrolytic copper plating process, or the like can facilitate processing. Regarding the method of forming the through-hole conductor 80B, in addition to the method of metallizing the inner wall surface of the through-hole 81B, a method of filling the through-hole 81B with a metal, a composite material of a metal and a resin, or the like may also be used.

[0139] The external electrode layer 71 is electrically connected to the cathode layer 30. In the example shown in Figure 8 etc., the external electrode layer 71 is provided on the surface of the through-hole conductor 80A and functions as a connection terminal of the capacitor array 102 (capacitor element 1). In the example shown in Figure 8 etc., the external electrode layer 71 is electrically connected to the cathode layer 30 through the via conductor 70 and functions as a connection terminal for the cathode layer 30.

[0140] Examples of materials constituting the external electrode layer 71 include metal materials containing low-resistance metals such as silver, gold, copper, etc. In this case, the external electrode layer 71 is formed by, for example, plating the surface of the through-hole conductor 80A.

[0141] In order to improve the adhesion between the external electrode layer 71 and other components, in this case, the adhesion between the external electrode layer 71 and the through-hole conductor 80A, 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 external electrode layer 71.

[0142] The external electrode layer 72 is electrically connected to the anode plate 10. In the example shown in Fig. 8 etc., the external electrode layer 72 is provided on the surface of the through-hole conductor 80B and functions as a connection terminal of the capacitor array 101 (capacitor element 1). In the example shown in Fig. 8 etc., the external electrode layer 72 is electrically connected to the anode plate 10 via the through-hole conductor 80B and functions as a connection terminal for the anode plate 10.

[0143] Examples of materials constituting the external electrode layer 72 include metal materials containing low-resistance metals such as silver, gold, copper, etc. In this case, the external electrode layer 72 is formed by, for example, plating the surface of the through-hole conductor 80B.

[0144] In order to improve the adhesion between the external electrode layer 72 and other components, in this case, the adhesion between the external electrode layer 72 and the through-hole conductor 80B, 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 external electrode layer 72.

[0145] The constituent materials of the external electrode layer 71 and the external electrode layer 72 are preferably the same at least in terms of type, but may be different from each other.

[0146] In the examples shown in Figures 7 to 9, each of the multiple capacitor elements 1 is provided with an external electrode layer 71 electrically connected to the cathode layer 30 and an external electrode layer 72 electrically connected to the anode plate 10, but at least one of the external electrode layer 71 and the external electrode layer 72 may be provided in common among the multiple capacitor elements 1.

[0147] In the example shown in FIGS. 7 to 9, the external electrode layers 71 and 72 are provided on both main surfaces of the sealing portion 60, but they may also be provided on only one main surface of the sealing portion 60.

[0148] Preferably, capacitor array 102 further includes resin-filled portions 90A formed by filling through holes 81A with a resin material. In the example shown in Fig. 8, resin-filled portions 90A are provided in spaces surrounded by through-hole conductors 80A on the inner wall surfaces of through holes 81A. By providing resin-filled portions 90A, the spaces within through holes 81A are eliminated, thereby suppressing delamination of through-hole conductors 80A.

[0149] It should be noted that capacitor array 102 does not necessarily have to have resin filling portion 90A. In this case, through-hole conductor 80A is preferably provided not only on the inner wall surface of through-hole 81A but also throughout the entire interior of through-hole 81A.

[0150] Preferably, the capacitor array 102 further includes a resin-filled portion 90B formed by filling the through-hole 81B with a resin material. In the example shown in Fig. 8, the resin-filled portion 90B is provided in a space surrounded by the through-hole conductors 80B on the inner wall surface of the through-hole 81B. The provision of the resin-filled portion 90B eliminates the space within the through-hole 81B, thereby suppressing delamination of the through-hole conductors 80B.

[0151] It should be noted that capacitor array 102 does not necessarily have to have resin filling portion 90B. In this case, it is preferable that through-hole conductor 80B is provided not only on the inner wall surface of through-hole 81B but also throughout the entire interior of through-hole 81B.

[0152] The capacitor element of the present invention is used, for example, in a composite electronic component, which includes, for example, the capacitor element of the present invention, external electrodes provided on the outside of the capacitor element of the present invention and electrically connected to the anode plate and the cathode layer, respectively, and an electronic component electrically connected to the external electrodes.

[0153] In a composite electronic component, the electronic component electrically connected to the external electrode may be a passive element, an active element, both a passive element and an active element, or a composite of a passive element and an active element.

[0154] An example of a passive element is an inductor.

[0155] Examples of active elements include a memory, a GPU (Graphical Processing Unit), a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and a PMIC (Power Management IC).

[0156] When the capacitor element of the present invention is used in a composite electronic component, the capacitor element of the present invention is treated as, for example, a substrate for mounting an electronic component, as described above. Therefore, by forming the capacitor element of the present invention as a whole into a sheet shape and further forming the electronic component to be mounted on the capacitor element of the present invention into a sheet shape, it is possible to electrically connect the capacitor element of the present invention and the electronic component in the thickness direction via through-hole conductors that penetrate the electronic component in the thickness direction. As a result, it is possible to configure passive and active elements as electronic components as a single module.

[0157] 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.

[0158] In a composite electronic component, a circuit layer may be formed on one main surface of a capacitor element sheet on which a plurality of capacitor elements of the present invention are laid out, and the circuit layer may then be electrically connected to a passive element or an active element as an electronic component.

[0159] Alternatively, the capacitor element of the present invention may be placed in a cavity pre-formed in a substrate, embedded in resin, and then a circuit layer may be formed on the resin. Another cavity of the same substrate may be equipped with a passive or active element as another electronic component.

[0160] 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 the circuit layer may then be electrically connected to a passive element or an active element as an electronic component.

[0161] The present specification discloses the following:

[0162] <1> A capacitor element comprising: an anode plate having a porous layer on at least one main surface; a dielectric layer provided on a surface of the porous layer; a cathode layer provided on the surface of the dielectric layer; and an insulating layer provided on the surface of the dielectric layer so as to partially overlap the cathode layer, wherein d1 is a thickness of an overlapping portion of the cathode layer and the insulating layer at an end of the insulating layer that overlaps the cathode layer, and d2 is a thickness of the insulating layer, and d1≧0.2×d2 is satisfied.

[0163] <2> The capacitor element according to <1>, wherein d1≦d2 is satisfied.

[0164] <3> The capacitor element according to <1> or <2>, wherein d1≧2 μm is satisfied.

[0165] <4> The capacitor element according to <3>, wherein d1≦100 μm is satisfied.

[0166] <5> The capacitor element according to any one of <1> to <4>, which satisfies 10 μm≦d2≦500 μm.

[0167] <6> The capacitor element according to any one of <1> to <5>, wherein, when the thickness of the cathode layer is d3, the following relationship is satisfied: 10 μm≦d3≦500 μm.

[0168] <7> The capacitor element according to any one of <1> to <6>, wherein the cathode layer includes a solid electrolyte layer provided on a surface of the dielectric layer and a carbon layer provided on the surface of the solid electrolyte layer, and the overlapping portion includes at least one of the solid electrolyte layer and the carbon layer, and the insulating layer.

[0169] <8> The capacitor element according to <7>, wherein the overlapping portion includes only the solid electrolyte layer and the insulating layer.

[0170] <9> The capacitor element according to <7>, wherein the overlapping portion includes only the solid electrolyte layer, the carbon layer, and the insulating layer.

[0171] <10> The capacitor element according to any one of <1> to <9>, further comprising a sealing layer that covers the insulating layer and the cathode layer.

[0172] REFERENCE SIGNS LIST 1 capacitor element 10 anode plate 11 core 12 porous layer 20 dielectric layer 30 cathode layer 31 solid electrolyte layer 32 conductor layer 32A first conductor layer 32B second conductor layer 34 portion where cathode layer and insulating layer overlap 40 insulating layer 40a end of insulating layer overlapping cathode layer 40A first insulating layer 40B second insulating layer 50 sealing layer 60 sealing portion 60A first sealing layer 60B second sealing layer 61, 62 dividing portion 70 via conductor 71, 72 external electrode layer 80A, 80B through-hole conductor 81A, 81B through hole 90A, 90B resin filled portion 101, 102 capacitor array

Claims

1. A capacitor element comprising: an anode plate having a porous layer on at least one principal surface; a dielectric layer provided on a surface of the porous layer; a cathode layer provided on the surface of the dielectric layer; and an insulating layer provided on the surface of the dielectric layer so as to partially overlap the cathode layer, wherein d1 is a thickness of an overlapping portion of the cathode layer and the insulating layer at an end of the insulating layer overlapping the cathode layer, and d2 is a thickness of the insulating layer, and d1 ≧ 0.2 × d2 is satisfied.

2. A capacitor element as described in claim 1, which satisfies d1≦d2.

3. A capacitor element according to claim 1 or 2, wherein d1≧2 μm is satisfied.

4. A capacitor element according to claim 3, wherein d1≦100 μm is satisfied.

5. A capacitor element according to any one of claims 1 to 4, which satisfies 10 μm≦d2≦500 μm.

6. The capacitor element according to any one of claims 1 to 5, wherein, when the thickness of the cathode layer is d3, the following relationship is satisfied: 10 µm≦d3≦500 µm.

7. A capacitor element according to any one of claims 1 to 6, wherein the cathode layer includes a solid electrolyte layer provided on a surface of the dielectric layer, and a carbon layer provided on the surface of the solid electrolyte layer, and the overlapping portion includes at least one of the solid electrolyte layer and the carbon layer, and the insulating layer.

8. The capacitor element of claim 7, wherein the overlapping portion includes only the solid electrolyte layer and the insulating layer.

9. The capacitor element of claim 7, wherein the overlapping portion includes only the solid electrolyte layer, the carbon layer, and the insulating layer.

10. The capacitor element according to claim 1, further comprising a sealing layer covering the insulating layer and the cathode layer.

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