Solid electrolytic capacitor and capacitor array

Abstract

A solid electrolytic capacitor 110 includes: an anode plate 10 including a core part 11, porous layers 12 provided on at least one main surface of the core part 11, and dielectric layers 13 provided on a surface of the porous layers 12; and cathode layers 20 provided on a surface of the dielectric layers 13. Each cathode layer 20 includes a solid electrolyte layer 21 provided on the surface of the dielectric layer 13. The solid electrolyte layer 21 includes, in the inside of pores of the dielectric layer 13, a conductive polymer layer in which both an electrically conductive polymer and an insulating material exist. The insulating material is a material that includes an OH group, a COOH group, a CO group, or an NH2 group in the molecule, is hygroscopic, and does not have a dopant function for the conductive polymer.

Description

Technical Field

[0001] The present invention relates to a solid electrolytic capacitor and a capacitor array.

Background Art

[0002] A solid electrolytic capacitor includes, for example, a dielectric layer provided on the surface of a porous layer provided on at least one main surface of a core portion, an anode plate made of a valve metal such as aluminum, and a cathode layer including a solid electrolyte layer provided on the surface of the dielectric layer.

[0003] Patent Document 1 discloses a solid electrolytic capacitor in which a moisture absorbent is disposed in the vicinity of a solid electrolyte provided on a dielectric. Patent Document 1 describes, as examples of the moisture absorbent, silica gel, calcium oxide, anhydrous calcium chloride, anhydrous sodium sulfate, and anhydrous copper sulfate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to Patent Document 1, since the moisture absorbent disposed in the vicinity of the solid electrolyte effectively adsorbs the intruding moisture that has permeated through the exterior, characteristic deterioration under high temperature and high humidity is said to be small.

[0006] However, when considering comprehensively covering the moisture intrusion paths into the solid electrolytic capacitor, in the method of disposing a layer of a moisture absorbent (hereinafter referred to as a hygroscopic layer) outside the solid electrolytic capacitor as shown in the drawings of Patent Document 1, it is difficult to dispose the hygroscopic layer around the entire circumference of the solid electrolytic capacitor. In particular, when manufacturing a capacitor array in which a plurality of solid electrolytic capacitors are present inside a sealing layer, and a single capacitor sheet is cut and divided into individual solid electrolytic capacitors, it is difficult to dispose the hygroscopic layer around the entire circumference of each solid electrolytic capacitor.

[0007] An object of the present invention is to provide a solid electrolytic capacitor capable of suppressing fluctuations in capacitance associated with moisture absorption. Further, an object of the present invention is to provide a capacitor array in which two or more of the above solid electrolytic capacitors are present inside a sealing layer.

Means for Solving the Problems

[0008] The solid electrolytic capacitor of the present invention includes an anode plate having a core portion, a porous layer provided on at least one main surface of the core portion, and a dielectric layer provided on the surface of the porous layer, 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. The solid electrolyte layer includes a conductive polymer layer in which a conductive polymer and an insulating material are mixed inside the pores of the dielectric layer. The insulating material is a material having hygroscopicity and containing an OH group, a COOH group, a CO group, or an NH2 group in the molecule, and having no dopant function with respect to the conductive polymer.

[0009] The capacitor array of the present invention includes a solid electrolytic capacitor of the present invention, a sealing layer provided so as to cover the solid electrolytic capacitor, a first external electrode and a second external electrode provided outside the sealing layer, a via conductor provided inside the sealing layer, and a through-hole conductor provided so as to penetrate the sealing layer in the thickness direction. Two or more of the solid electrolytic capacitors are present inside the sealing layer. The side wall of the through-hole conductor is electrically connected to the end face of the anode plate of the solid electrolytic capacitor. The first external electrode is electrically connected to the anode plate of the solid electrolytic capacitor through the through-hole conductor. The second external electrode is electrically connected to the cathode layer of the solid electrolytic capacitor through the via conductor.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a solid electrolytic capacitor capable of suppressing fluctuations in capacitance due to moisture absorption. Furthermore, according to the present invention, it is possible to provide a capacitor array in which two or more of the solid electrolytic capacitors are present inside the sealing layer.

Brief Description of the Drawings

[0011]

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Best Mode for Carrying Out the Invention

[0012] Hereinafter, the solid electrolytic capacitor and capacitor array of the present invention will be described. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without changing the gist of the present invention. In addition, combinations of two or more of the individual desirable configurations of the present invention described below are also within the scope of the present invention.

[0013] In the examples shown below, the capacitor array of the present invention will be described with reference to the drawings. The solid electrolytic capacitor included in such a capacitor array is also one of the present inventions. The solid electrolytic capacitor of the present invention may be present in two or more within the sealing layer, or may be present only one.

[0014] The drawings shown below are schematic diagrams, and their dimensions, scales of aspect ratios, etc. may be different from those of actual products.

[0015] FIG. 1 is a cross-sectional view schematically showing an example of the capacitor array of the present invention. FIG. 2 is an enlarged cross-sectional view of the portion surrounded by the broken line in the capacitor array shown in FIG. 1. FIG. 3 is a perspective view schematically showing the internal structure of the capacitor array shown in FIG. 1. In FIG. 3, the first external electrode and the second external electrode are omitted. Note that FIG. 1 is a cross-sectional view along the line A-A of the capacitor array shown in FIG. 3.

[0016] The capacitor array 100 shown in FIG. 1 includes a plurality of solid electrolytic capacitors 110 and a sealing layer 120 provided so as to cover the solid electrolytic capacitors.

[0017] The solid electrolytic capacitor 110 includes an anode plate 10 and a cathode layer 20.

[0018] The anode plate 10 has a core part 11, a porous layer 12 provided on at least one main surface of the core part 11, and a dielectric layer 13 (see Fig. 2) provided on the surface of the porous layer 12. In Fig. 1, the porous layer 12 of the anode plate 10 is shown alone, but actually, as shown in Fig. 2, a part of the solid electrolyte layer 21 constituting the cathode layer 20 is provided inside the pores (recesses) of the dielectric layer 13. The same applies to the following cross-sectional views.

[0019] The anode plate 10 is made of a valve-acting metal that exhibits a so-called valve action. Examples of the valve-acting metal include a single metal such as aluminum, tantalum, niobium, titanium, zirconium, or an alloy containing at least one of these metals. Among these, aluminum or an aluminum alloy is preferable.

[0020] The shape of the anode plate 10 is preferably flat, and more preferably in the form of a foil. In the anode plate 10, it is sufficient that the porous layer 12 is provided on at least one main surface of the core part 11, and the porous layer 12 may be provided on both main surfaces of the core part 11. The porous layer 12 is preferably an etching layer formed on the surface of the anode plate 10.

[0021] The thickness of the anode plate 10 before the etching treatment is preferably 60 μm or more and 200 μm or less. The thickness of the core part 11 that is not etched after the etching treatment is preferably 15 μm or more and 70 μm or less. The thickness of the porous layer 12 is designed according to the required withstand voltage and capacitance, but it is preferably 10 μm or more and 180 μm or less for the porous layers 12 on both sides of the core part 11 combined.

[0022] The pore diameter of the porous layer 12 is preferably 10 nm or more and 600 nm or less. The pore diameter of the porous layer 12 means the median diameter D50 measured by a mercury porosimeter. The pore diameter of the porous layer 12 can be controlled, for example, by adjusting various conditions in the etching.

[0023] The dielectric layer 13 is porous, reflecting the surface state of the porous layer 12, and has a fine uneven surface shape (see Fig. 2). The dielectric layer 13 is preferably made of the oxide film of the valve action metal. For example, when an aluminum foil is used as the anode plate 10, a dielectric layer 13 made of an oxide film can be formed by performing an anodic oxidation treatment (also called a forming treatment) on the surface of the aluminum foil in an aqueous solution containing ammonium adipate or the like.

[0024] The thickness of the dielectric layer 13 is designed according to the required withstand voltage and capacitance, but it is preferably 10 nm or more and 100 nm or less.

[0025] The cathode layer 20 is provided on the surface of the dielectric layer 13. When the first insulating layer 30 described later is provided on the anode plate 10, it is preferable that the cathode layer 20 is provided on the surface of the dielectric layer 13 within the region surrounded by the first insulating layer 30 (hereinafter also referred to as the element region). Note that the cathode layer 20 may be provided so as to extend to the surface of the first insulating layer 30.

[0026] The cathode layer 20 includes a solid electrolyte layer 21 provided on the surface of the dielectric layer 13. The cathode layer 20 preferably further includes a conductor layer 22 provided on the surface of the solid electrolyte layer 21. In Fig. 1, the solid electrolyte layer 21 is shown in a state completely separated from the porous layer 12 of the anode plate 10, but actually, as shown in Fig. 2, a part of the solid electrolyte layer 21 is provided inside the pores (recesses) of the dielectric layer 13.

[0027] The solid electrolyte layer 21 contains a conductive polymer.

[0028] Examples of the material constituting the solid electrolyte layer 21 include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferable, and poly(3,4-ethylenedioxythiophene) called PEDOT is particularly preferable. Further, the conductive polymer may contain a dopant such as polystyrene sulfonic acid (PSS).

[0029] The thickness of the solid electrolyte layer 21 from the surface of the anode plate 10 is preferably 2 μm or more and 20 μm or less.

[0030] The thickness of the solid electrolyte layer 21 can be measured by an electron micrograph of a cross-section in the thickness direction of the anode plate 10 as shown in FIG. 2. The method for measuring the thickness of each layer constituting the solid electrolyte layer 21 described later is the same.

[0031] The solid electrolyte layer 21 includes a conductive polymer layer in which a conductive polymer and an insulating material are mixed inside the pores of the dielectric layer 13. The insulating material is a material that contains an OH group, a COOH group, a CO group, or an NH2 group in the molecule, has hygroscopicity, and does not have a doping function with respect to the conductive polymer.

[0032] In the solid electrolytic capacitor 110, a hygroscopic insulating material is included in a portion of the solid electrolyte layer 21 provided inside the pores of the dielectric layer 13. Therefore, the change in capacitance due to the moisture absorption of the conductive polymer can be suppressed by the expansion of the insulating material.

[0033] For example, when manufacturing the solid electrolytic capacitor 110 by cutting a single capacitor sheet, particularly when manufacturing a capacitor array 100 in which a plurality of solid electrolytic capacitors 110 are present inside the sealing layer 120 and cutting a single capacitor sheet into individual solid electrolytic capacitors 110, unlike Patent Document 1, it is not necessary to dispose a moisture absorption layer around the entire circumference of the solid electrolytic capacitor 110 after cutting, so the change in capacitance due to moisture absorption can be easily suppressed.

[0034] Also, in the capacitor array 100, when the via conductor 50, through-hole conductor 61, or through-hole conductor 62, which will be described later, is provided, in the method of disposing the moisture absorption layer around the entire circumference of the solid electrolytic capacitor 110, since through-holes for forming the via conductor 50 or the like have to be formed in the moisture absorption layer, it becomes difficult to obtain a sufficient moisture-proof effect. From this aspect as well, it is preferable that the solid electrolyte layer 21 contains an insulating material having hygroscopicity. Note that this is the same not only when a plurality of solid electrolytic capacitors 110 are present inside the sealing layer 120, but also when one solid electrolytic capacitor 110 is present inside the sealing layer 120.

[0035] As described above, the effect of the solid electrolyte layer 21 containing an insulating material having hygroscopicity can be said to be an effect of the capacitor array 100 as well as an effect of the solid electrolytic capacitor 110.

[0036] Examples of the insulating material contained in the conductive polymer layer include phenolic materials and the like. The insulating material contained in the conductive polymer layer may have a function of supplying hydrogen radicals (H·) to radicals (R·) generated starting from heat in the molecular chain of the conductive polymer and peroxy radicals (ROO·) generated by the reaction of the above radicals (R·) with oxygen to stabilize them.

[0037] In the example shown in FIG. 2, the solid electrolyte layer 21 includes a first conductive polymer layer 21A, a second conductive polymer layer 21B, and a third conductive polymer layer 21C. In this example, the first conductive polymer layer 21A and the second conductive polymer layer 21B are provided inside the pores of the dielectric layer 13, and the second conductive polymer layer 21B contains an insulating material. However, only a conductive polymer layer containing an insulating material may be provided inside the pores of the dielectric layer 13.

[0038] In addition, it is preferable that the insulating material contained in the conductive polymer layer does not have a dopant function with respect to the conductive polymer contained in the solid electrolyte layer 21. For example, when the solid electrolyte layer 21 includes a first conductive polymer layer 21A containing a first conductive polymer, a second conductive polymer layer 21B containing a second conductive polymer, and a third conductive polymer layer 21C containing a third conductive polymer, it is preferable that the insulating material does not have a dopant function with respect to the first conductive polymer, the second conductive polymer, and the third conductive polymer.

[0039] The first conductive polymer layer 21A is provided inside the pores (recesses) of the dielectric layer 13. The first conductive polymer layer 21A may cover the entire pores of the dielectric layer 13 or may cover a part of the pores of the dielectric layer 13.

[0040] The first conductive polymer layer 21A is a layer containing a first conductive polymer. The first conductive polymer may be only one kind or two or more kinds. The first conductive polymer layer 21A may be one layer or two or more layers.

[0041] The first conductive polymer is, for example, a conductive polymer represented by poly(3,4-ethylenedioxythiophene) and is a material soluble in a solvent.

[0042] The first conductive polymer may contain a dopant as required.

[0043] The first conductive polymer layer 21A is formed, for example, by a method of applying a liquid containing a first conductive polymer, preferably a liquid in which the first conductive polymer is dissolved, to the surface of the anode plate 10 and drying it. Specifically, the first conductive polymer layer 21A can be formed in a predetermined region by applying the above liquid to the surface of the anode plate 10 by methods such as an immersion method (dip method), sponge transfer, screen printing, dispenser coating, inkjet printing, etc.

[0044] The second conductive polymer layer 21B is provided inside the pores (recesses) of the dielectric layer 13 and covers the first conductive polymer layer 21A. The second conductive polymer layer 21B may cover the entire first conductive polymer layer 21A or may cover a part of the first conductive polymer layer 21A. The second conductive polymer layer 21B may fill the pores (recesses) of the dielectric layer 13.

[0045] The second conductive polymer layer 21B is a layer in which a second conductive polymer and an insulating material are mixed. The second conductive polymer may be only one type or two or more types. Similarly, the insulating material may be only one type or two or more types. The second conductive polymer layer 21B may be one layer or two or more layers.

[0046] The second conductive polymer is preferably a conductive polymer different from the first conductive polymer. The second conductive polymer is, for example, a conductive polymer represented by poly(3,4-ethylenedioxythiophene), which has a larger particle size than the first conductive polymer, is insoluble in a solvent, but has high heat resistance.

[0047] The second conductive polymer may contain a dopant as necessary.

[0048] It is preferable that the insulating material is not unevenly distributed inside the second conductive polymer layer 21B, and it is more preferable that the insulating material is uniformly dispersed inside the second conductive polymer layer 21B.

[0049] The thickness of the second conductive polymer layer 21B may be the same as the thickness of the first conductive polymer layer 21A, may be larger than the thickness of the first conductive polymer layer 21A, or may be smaller than the thickness of the first conductive polymer layer 21A.

[0050] The second conductive polymer layer 21B is formed, for example, by a method of simultaneously applying a liquid containing a second conductive polymer, preferably a liquid in which the second conductive polymer is dispersed, and a liquid containing an insulating material, preferably a liquid in which the insulating material is dissolved, onto the surface of the anode plate 10 on which the first conductive polymer layer 21A is formed, and then drying them. Specifically, these liquids can be simultaneously applied onto the surface of the anode plate 10 on which the first conductive polymer layer 21A is formed by methods such as dipping method (dip coating), sponge transfer, screen printing, dispenser coating, inkjet printing, etc., so that the second conductive polymer layer 21B can be formed in a predetermined region.

[0051] The third conductive polymer layer 21C is provided on the surface of the anode plate 10 and covers at least the second conductive polymer layer 21B. The third conductive polymer layer 21C may cover not only the second conductive polymer layer 21B but also the first conductive polymer layer 21A.

[0052] The third conductive polymer layer 21C is a layer containing a third conductive polymer. The third conductive polymer layer 21C preferably further contains a binder. The third conductive polymer layer 21C may be a single layer or two or more layers.

[0053] The third conductive polymer may be the same conductive polymer as the first conductive polymer or the same conductive polymer as the second conductive polymer. The third conductive polymer may be only one type or two or more types. The third conductive polymer may contain a dopant as required.

[0054] The thickness of the third conductive polymer layer 21C is preferably greater than the thickness of the first conductive polymer layer 21A and preferably greater than the thickness of the second conductive polymer layer 21B.

[0055] The third conductive polymer layer 21C is formed, for example, by applying a liquid containing a third conductive polymer to the surface of the anode plate 10 on which the first conductive polymer layer 21A and the second conductive polymer layer 21B are formed and then drying it. Specifically, the above liquid is applied to the surface of the anode plate 10 on which the first conductive polymer layer 21A and the second conductive polymer layer 21B are formed by methods such as dipping method, sponge transfer, screen printing, dispenser coating, inkjet printing, etc., so that the third conductive polymer layer 21C can be formed in a predetermined region.

[0056] Alternatively, a polymerization film of the third conductive polymer may be formed on the surface of the anode plate 10 on which the first conductive polymer layer 21A and the second conductive polymer layer 21B are formed by using a liquid containing a monomer such as 3,4-ethylenedioxythiophene. Also in this case, the above liquid is applied to the surface of the anode plate 10 on which the first conductive polymer layer 21A and the second conductive polymer layer 21B are formed by methods such as dipping method, sponge transfer, screen printing, dispenser coating, inkjet printing, etc., so that the third conductive polymer layer 21C can be formed in a predetermined region.

[0057] In order to suppress the risk of short circuit caused by direct contact between the core part 11 of the anode plate 10 and the conductor layer 22, the third conductive polymer layer 21C is preferably formed using a liquid having a higher viscosity than the liquid used to form the first conductive polymer layer 21A and the second conductive polymer layer 21B so that the core part 11 of the anode plate 10 is not exposed on the surface.

[0058] The conductor layer 22 includes at least one of a conductive resin layer and a metal layer. The conductor layer 22 may be only a conductive resin layer or only a metal layer. The conductor layer 22 may cover the entire solid electrolyte layer 21 or may cover a part of the solid electrolyte layer 21.

[0059] Examples of the conductive resin layer include a conductive adhesive layer containing at least one conductive filler selected from the group consisting of a silver filler, a copper filler, a nickel filler, and a carbon filler.

[0060] 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 mainly composed of these metals. Here, the "main component" refers to the elemental component with the largest weight ratio.

[0061] The conductor layer 22 includes, for example, a first conductor layer 22A provided on the surface of the solid electrolyte layer 21 and a second conductor layer 22B provided on the surface of the first conductor layer 22A. Thus, the conductor layer 22 preferably includes a plurality of types of conductor layers.

[0062] The first conductor layer 22A is, for example, a conductive resin layer containing a conductive filler. The conductive filler is preferably at least one selected from the group consisting of a silver filler, a copper filler, a nickel filler, and a carbon filler.

[0063] The second conductor layer 22B is, for example, a conductive resin layer containing a metal filler. The metal filler is preferably at least one selected from the group consisting of a silver filler, a copper filler, and a nickel filler.

[0064] As an example, the conductor layer 22 includes a carbon layer as the first conductor layer 22A and a copper layer as the second conductor layer 22B.

[0065] The carbon layer is provided to electrically and mechanically connect the solid electrolyte layer 21 and the copper layer. The carbon layer can be formed in a predetermined region by applying a carbon paste onto the solid electrolyte layer 21 by methods such as dipping method, sponge transfer, screen printing, dispenser coating, inkjet printing, etc. Note that it is preferable that the copper layer of the next process is laminated while the carbon layer is in a viscous state before drying. The thickness of the carbon layer is preferably 2 μm or more and 20 μm or less.

[0066] The copper layer can be formed by printing a copper paste onto the carbon layer by methods such as dipping method, 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.

[0067] As shown in FIGS. 1 and 3, it is preferable that a first insulating layer 30 is provided in a region where the cathode layer 20 is not formed on the surface of the porous layer 12. The first insulating layer 30 is provided so as to surround the cathode layer 20 when viewed in the thickness direction. The first insulating layer 30 divides the element region of the solid electrolytic capacitor 110.

[0068] Among the plurality of solid electrolytic capacitors 110, the peripheries of all the solid electrolytic capacitors 110 may be surrounded by the first insulating layer 30, or there may be a solid electrolytic capacitor 110 not surrounded by the first insulating layer 30. In the solid electrolytic capacitor 110 surrounded by the first insulating layer 30, the entire periphery of the solid electrolytic capacitor 110 may be surrounded by the first insulating layer 30, or a part of the periphery of the solid electrolytic capacitor 110 may be surrounded by the first insulating layer 30.

[0069] Furthermore, a first insulating layer 31 may be provided in a region where the cathode layer 20 is not formed on the surface of the porous layer 12. The first insulating layer 31 is provided inside the cathode layer 20 when viewed in the thickness direction. In other words, the first insulating layer 31 is provided within the element region of the solid electrolytic capacitor 110. The first insulating layer 31 is preferably provided away from the first insulating layer 30.

[0070] At least one first insulating layer 31 may be provided in at least one of the plurality of element regions. In the example shown in FIG. 3, two first insulating layers 31 are provided in each element region.

[0071] Both the first insulating layers 30 and 31 may be provided on the surface of the porous layer 12, or only one of them may be provided.

[0072] The first insulating layers 30 and 31 may be provided on the surface of the dielectric layer 13 on the porous layer 12. The first insulating layers 30 and 31 are preferably provided so as to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0073] The first insulating layers 30 and 31 contain an insulating material.

[0074] The first insulating layers 30 and 31 are preferably made of resin. Examples of the resin constituting the first insulating layers 30 and 31 include insulating resins such as polyphenylsulfone resin, polyethersulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene·perfluoroalkyl vinyl ether copolymer, etc.), polyimide resin, polyamideimide resin, epoxy resin, and their derivatives or precursors. The first insulating layers 30 and 31 may be composed of the same resin or different resins.

[0075] Since the inclusion of inorganic fillers in the first insulating layers 30 and 31 may have an adverse effect on the active part of the solid electrolytic capacitor 110, the first insulating layers 30 and 31 preferably consist of a resin-only system.

[0076] The first insulating layers 30 and 31 can be formed, for example, by applying a mask material such as a composition containing an insulating resin onto the porous layer 12 by a method such as sponge transfer, screen printing, dispenser coating, inkjet printing, or the like.

[0077] The thickness of the first insulating layers 30 and 31 from the surface of the anode plate 10 is preferably 20 μm or less. The thickness of the first insulating layers 30 and 31 from the surface of the anode plate 10 may be 0 μm, but is preferably 2 μm or more. The thicknesses of the first insulating layers 30 and 31 may be the same or different.

[0078] The thickness of the first insulating layers 30 and 31 can be measured by an electron micrograph of a cross section in the thickness direction of the anode plate 10.

[0079] The planar shape of the first insulating layer 31 viewed from the thickness direction is not particularly limited, and examples include polygons such as quadrilaterals, circles, ellipses, and the like. When two or more first insulating layers 31 are provided in the element region, the sizes and planar shapes of the first insulating layers 31 viewed from the thickness direction may be the same, or some or all of them may be different.

[0080] The position where the first insulating layer 31 is provided in the element region is not particularly limited. When two or more first insulating layers 31 are provided in the element region, the positions where the first insulating layers 31 are provided may be the same, or some or all of them may be different.

[0081] Although not shown, a part of the first conductive polymer layer 21A and / or a part of the second conductive polymer layer 21B may be exposed on the surface of the anode plate 10. In that case, it is preferable that the area of the region where the first conductive polymer layer 21A and the second conductive polymer layer 21B are present on the surface of the anode plate 10 is larger than the area of the region where the first conductive polymer layer 21A and the second conductive polymer layer 21B are not present on the surface of the anode plate 10. Note that, on the surface of the anode plate 10, only a part of the first conductive polymer layer 21A may be exposed, only a part of the second conductive polymer layer 21B may be exposed, or both a part of the first conductive polymer layer 21A and a part of the second conductive polymer layer 21B may be exposed.

[0082] The first conductive polymer layer 21A and / or the second conductive polymer layer 21B of the portion exposed on the surface of the anode plate 10 preferably contacts the first insulating layer 30. In particular, it is preferable that a part of the first conductive polymer layer 21A and / or a part of the second conductive polymer layer 21B is exposed along the inner edge of the first insulating layer 30. In that case, a part of the first conductive polymer layer 21A and / or a part of the second conductive polymer layer 21B may be exposed along the entire inner edge of the first insulating layer 30, or may be exposed along a part of the inner edge of the first insulating layer 30.

[0083] A part of the third conductive polymer layer 21C may enter into the pores of the dielectric layer 13. When the third conductive polymer layer 21C covers the pores of the dielectric layer 13 and enters into the pores of the dielectric layer 13, the occurrence of delamination between the porous layer 12 and the solid electrolyte layer 21 is likely to be suppressed due to the anchor effect of the third conductive polymer layer 21C.

[0084] The depth at which the third conductive polymer layer 21C enters is not particularly limited, and when observing the cross-section in the thickness direction of the anode plate 10 as shown in FIG. 2, it is sufficient that a part of the third conductive polymer layer 21C enters into the pores of the dielectric layer 13.

[0085] When a part of the third conductive polymer layer 21C enters into the pores of the dielectric layer 13, the cathode layer 20 may include a conductor layer 22, and the conductor layer 22 may include a conductive resin layer containing a metal filler. For example, when the second conductor layer 22B is a conductive resin layer containing a metal filler, the difference in thermal properties such as the linear expansion coefficient becomes large between the solid electrolyte layer 21 and the conductor layer 22, so delamination is likely to occur between the solid electrolyte layer 21 and the conductor layer 22. Even in such a case, by allowing a part of the third conductive polymer layer 21C to enter into the pores of the dielectric layer 13, the occurrence of delamination between the solid electrolyte layer 21 and the conductor layer 22 can be suppressed.

[0086] The sealing layer 120 is preferably provided so as to cover all of the outer peripheral portion of the solid electrolytic capacitor 110, that is, so as to cover the top, bottom, left, and right of the solid electrolytic capacitor 110.

[0087] The sealing layer 120 contains an insulating material.

[0088] The sealing layer 120 is preferably made of resin. Examples of the resin constituting the sealing layer 120 include epoxy resin, phenolic resin, etc. The sealing layer 120 may be made of the same resin as the first insulating layer 30 or 31.

[0089] The sealing layer 120 preferably further includes a filler. Examples of the filler contained in the sealing layer 120 include inorganic fillers such as silica particles, alumina particles, and metal particles.

[0090] The sealing layer 120 may be composed of only one layer or may be composed of two or more layers. When the sealing layer 120 is composed of two or more layers, the materials constituting each layer may be the same or different from each other.

[0091] Between the sealing layer 120 and the cathode layer 20, between the sealing layer 120 and the first insulating layer 30, or between the sealing layer 120 and the first insulating layer 31, layers such as a stress relaxation layer and a moisture-proof film may be provided.

[0092] The stress relaxation layer is preferably composed of an insulating resin. Examples of the insulating resin constituting the stress relaxation layer include epoxy resin, phenolic resin, silicone resin, and the like. Further, the stress relaxation layer preferably contains a filler. Examples of the filler contained in the stress relaxation layer include inorganic fillers such as silica particles, alumina particles, and metal particles. The insulating resin constituting the stress relaxation layer is preferably different from the resin constituting the sealing layer 120.

[0093] Since the sealing layer 120 is required to have characteristics such as adhesion to the external electrode as an exterior body, it is difficult to simply match the linear expansion coefficient with the solid electrolytic capacitor 110 or select a resin with an arbitrary elastic modulus. In contrast, by providing a stress relaxation layer, it is possible to adjust the thermal stress design without losing the respective functions of the solid electrolytic capacitor 110 and the sealing layer 120.

[0094] The stress relaxation layer preferably has lower moisture permeability than the sealing layer 120. In this case, in addition to adjusting the stress, it is possible to reduce the intrusion of moisture into the solid electrolytic capacitor 110. The moisture permeability of the stress relaxation layer can be adjusted by factors such as the type of insulating resin constituting the stress relaxation layer and the amount of filler contained in the stress relaxation layer.

[0095] As shown in FIG. 1, the capacitor array 100 may further include a first external electrode 41 and a second external electrode 42 provided outside the sealing layer 120. In the example shown in FIG. 1, the first external electrode 41 and the second external electrode 42 are provided on both main surface sides of the sealing layer 120, but they may be provided on only one of the main surface sides.

[0096] The first external electrode 41 is electrically connected to the anode plate 10 of the solid electrolytic capacitor 110. The second external electrode 42 is electrically connected to the cathode layer 20 of the solid electrolytic capacitor 110. The first external electrode 41 and the second external electrode 42 can function as connection terminals of the solid electrolytic capacitor 110.

[0097] Examples of materials constituting the first external electrode 41 and the second external electrode 42 include low-resistance metals such as silver, gold, and copper. The material constituting the first external electrode 41 may be the same as or different from the material constituting the second external electrode 42. The first external electrode 41 and the second external electrode 42 are formed, for example, by a method such as plating treatment.

[0098] In order to improve the adhesion between the first external electrode 41 and other members or between the second external electrode 42 and other members, as the material constituting the first external electrode 41 and the second external electrode 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.

[0099] As shown in FIGS. 1 and 3, the capacitor array 100 may further include a via conductor 50 provided inside the sealing layer 120. In the example shown in FIG. 1, the via conductor 50 is provided on both main surface sides of the sealing layer 120, but it may be provided on only one of the main surface sides.

[0100] The via conductor 50 is provided so as to reach the cathode layer 20 (the second conductor layer 22B in the example shown in FIG. 1) from the surface of the sealing layer 120 in the thickness direction. Thereby, the second external electrode 42 is electrically connected to the cathode layer 20 of the solid electrolytic capacitor 110 via the via conductor 50.

[0101] Examples of materials constituting the via conductor 50 include low-resistance metals such as silver, gold, and copper.

[0102] The via conductor 50 is formed, for example, as follows. First, the sealing layer 120 is drilled, laser processed, etc. to form a hole reaching the cathode layer 20 (for example, the second conductor layer 22B) from the surface of the sealing layer 120 in the thickness direction. Then, the via conductor 50 is formed by performing plating treatment on the inner wall surface of the hole formed in the sealing layer 120 or by filling a conductive paste and then performing heat treatment.

[0103] As shown in FIGS. 1 and 3, the capacitor array 100 may further include through-hole conductors 61 and 62 provided so as to penetrate the sealing layer 120 in the thickness direction. The through-hole conductors 61 and 62 are provided so as to penetrate the first insulating layer 31 in the thickness direction. In the example shown in FIGS. 1 and 3, both the through-hole conductors 61 and 62 are provided, but only one of them may be provided.

[0104] The through-hole conductor 61 is provided inside a first through-hole 71 that penetrates the first insulating layer 31 in the thickness direction. In the example shown in FIGS. 1 and 3, the through-hole conductor 61 is provided so as to penetrate the solid electrolytic capacitor 110 and the sealing layer 120 in the thickness direction. Through the through-hole conductor 61, the first external electrode 41 is electrically connected to the anode plate 10 of the solid electrolytic capacitor 110. As shown in FIG. 1, it is preferable that the through-hole conductor 61 is electrically connected to the end face of the anode plate 10 of the solid electrolytic capacitor 110 at the inner wall of the first through-hole 71 (that is, the side wall of the through-hole conductor 61). In the example shown in FIGS. 1 and 3, the through-hole conductor 61 is provided so as to fill the first through-hole 71, but the through-hole conductor 61 may be provided on at least the inner wall surface of the first through-hole 71. When the through-hole conductor 61 is provided on the inner wall surface of the first through-hole 71, the first through-hole 71 is preferably filled with a resin material. In this case, the resin material filling the first through-hole 71 may or may not have conductivity.

[0105] The through-hole conductor 62 is provided inside a second through-hole 72 that penetrates the first insulating layer 31 in the thickness direction. The aperture diameter of the second through-hole 72 is preferably larger than the aperture diameter of the first through-hole 71. In the examples shown in FIGS. 1 and 3, the through-hole conductor 62 is provided so as to penetrate the solid electrolytic capacitor 110 and the sealing layer 120 in the thickness direction. The through-hole conductor 62 is electrically connected to the cathode layer 20 of the solid electrolytic capacitor 110 via the second external electrode 42 and the via conductor 50. As shown in FIG. 1, the through-hole conductor 62 is preferably electrically insulated from the anode plate 10 of the solid electrolytic capacitor 110 at the inner wall of the second through-hole 72 (i.e., the side wall of the through-hole conductor 62). In the examples shown in FIGS. 1 and 3, the through-hole conductor 62 is provided so as to fill a third through-hole 73 having an aperture diameter smaller than that of the second through-hole 72, but the through-hole conductor 62 may be provided on at least the inner wall surface of the third through-hole 73. The aperture diameter of the third through-hole 73 may be the same as the aperture diameter of the first through-hole 71, may be larger than the aperture diameter of the first through-hole 71, or may be smaller than the aperture diameter of the first through-hole 71. When the through-hole conductor 62 is provided on the inner wall surface of the third through-hole 73, the third through-hole 73 is preferably filled with a resin material. In this case, the resin material filling the third through-hole 73 may or may not have conductivity.

[0106] The cross-sectional shapes of the first through-hole 71, the second through-hole 72, and the third through-hole 73 as viewed from the thickness direction are not particularly limited, and examples include polygons such as quadrilaterals, circles, ellipses, and the like. Note that the aperture diameter refers to the diameter when the cross-sectional shape is circular, and the maximum length passing through the center of the cross-section in other cases. These through-holes may have a taper in which the aperture diameter decreases in the thickness direction.

[0107] The through-hole conductors 61 and 62 may be formed on at least the inner wall surface of the through-hole. The inner wall surface of the through-hole is metallized with a low-resistance metal such as copper, gold, or silver. For ease of processing, for example, it can be metallized by electroless copper plating or electrolytic copper plating. Note that the metallization of the through-hole conductors 61 and 62 is not limited to the case of metallizing only the inner wall surface of the through-hole, and a metal or a composite material of metal and resin may be filled in the through-hole.

[0108] Although not shown in FIGS. 1 and 3, the capacitor array 100 may further include through-hole conductors other than the through-hole conductors 61 and 62. For example, the capacitor array 100 may further include a through-hole conductor that is not electrically connected to either the anode plate 10 or the cathode layer 20 of the solid electrolytic capacitor 110.

[0109] In the capacitor array 100, there may be two or more solid electrolytic capacitors 110 inside the sealing layer 120. The plurality of solid electrolytic capacitors 110 may be arranged linearly or planar when viewed in the thickness direction. Also, the plurality of solid electrolytic capacitors 110 may be arranged regularly or irregularly when viewed in the thickness direction. The size and planar shape of the solid electrolytic capacitor 110 when viewed in the thickness direction may be the same, or some or all of them may be different. Two or more types of solid electrolytic capacitors 110 having different areas when viewed in the thickness direction may be included.

[0110] The capacitor array 100 may include a solid electrolytic capacitor 110 whose planar shape as viewed from the thickness direction is not rectangular. In this specification, "rectangular" means a square or a rectangle. Therefore, for example, solid electrolytic capacitors 110 having a planar shape that is a polygon other than a rectangle, such as a quadrilateral, triangle, pentagon, hexagon, etc., a shape including a curved portion, a circular shape, an elliptical shape, etc. may be included in the capacitor array 100. In this case, two or more types of solid electrolytic capacitors 110 having different planar shapes may be included in the capacitor array 100. Further, in addition to the solid electrolytic capacitor 110 whose planar shape is not rectangular, a solid electrolytic capacitor 110 whose planar shape is rectangular may or may not be included in the capacitor array 100.

[0111] As shown in FIGS. 1 and 3, it is preferable that the anode plate 10 is divided by a slit between at least one pair of adjacent solid electrolytic capacitors 110 among the plurality of solid electrolytic capacitors 110. That is, the slit between at least one pair of adjacent solid electrolytic capacitors 110 preferably penetrates the anode plate 10 in the thickness direction. Between adjacent solid electrolytic capacitors 110, it is sufficient that the anode plate 10 is physically divided. Therefore, between adjacent solid electrolytic capacitors 110, the anode plate 10 may be electrically divided or may be electrically connected.

[0112] The width of the slit between adjacent solid electrolytic capacitors 110 is not particularly limited, but is preferably 15 μm or more, more preferably 30 μm or more, and even more preferably 50 μm or more. On the other hand, the width of the slit between adjacent solid electrolytic capacitors 110 is preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less.

[0113] The slit between adjacent solid electrolytic capacitors 110 may have a taper whose width decreases in the thickness direction. In that case, the taper of the slit between adjacent solid electrolytic capacitors 110 may or may not reach the anode plate 10.

[0114] It is preferable that the space between adjacent solid electrolytic capacitors 110 is filled with the same material as the sealing layer 120. For example, as shown in FIG. 1, the space between adjacent solid electrolytic capacitors 110 may be filled with the sealing layer 120.

[0115] Alternatively, the space between adjacent solid electrolytic capacitors 110 may be filled with the same material as the stress relaxation layer. For example, when the capacitor array 100 includes a stress relaxation layer, the space between adjacent solid electrolytic capacitors 110 may be filled with the stress relaxation layer.

[0116] Hereinafter, as an example of a method for manufacturing the capacitor array of the present invention, an example of a method for manufacturing the capacitor array 100 shown in FIG. 1 will be described step by step with reference to the drawings.

[0117] FIG. 4 is a perspective view schematically showing an example of a step of preparing an anode plate. FIG. 5 is an enlarged cross-sectional view of a portion surrounded by a broken line in the anode plate shown in FIG. 4.

[0118] For example, an anode plate 10 made of valve action metal is prepared. The anode plate 10 has a core portion 11 (see FIG. 1), a porous layer 12 (see FIGS. 1 and 5) provided on at least one main surface of the core portion 11, and a dielectric layer 13 (see FIG. 5) provided on the surface of the porous layer 12.

[0119] For example, by performing an anodization treatment on the anode plate 10 having the porous layer 12 provided on at least one main surface of the core portion 11, the dielectric layer 13 can be formed on the surface of the porous layer 12.

[0120] Alternatively, a formed foil may be prepared as the anode plate 10 having the dielectric layer 13 provided on the surface of the porous layer 12.

[0121] As shown in FIG. 4, a first insulating layer 30 is formed on the surface of the porous layer 12 in order to divide the anode plate 10 into a plurality of element regions. The first insulating layer 30 may be formed on the surface of the dielectric layer 13 on the porous layer 12. The first insulating layer 30 is preferably formed so as to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0122] Furthermore, a first insulating layer 31 may be formed on the surface of the porous layer 12 within at least one element region. In that case, the first insulating layer 31 is preferably formed away from the first insulating layer 30. The first insulating layer 31 may be formed on the surface of the dielectric layer 13 on the porous layer 12. The first insulating layer 31 is preferably formed so as to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0123] Next, a cathode layer 20 is formed on the surface of the dielectric layer 13 within the element region divided by the first insulating layer 30. Note that the cathode layer 20 may be formed so as to extend to the surface of the first insulating layer 30.

[0124] The step of forming the cathode layer 20 includes a step of forming a solid electrolyte layer 21 containing a conductive polymer on the surface of the dielectric layer 13.

[0125] The step of forming the solid electrolyte layer 21 includes, for example, a step of forming a first conductive polymer layer 21A, a step of forming a second conductive polymer layer 21B, and a step of forming a third conductive polymer layer 21C.

[0126] FIG. 6 is a cross-sectional view schematically showing an example of the step of forming the first conductive polymer layer.

[0127] As shown in FIG. 6, a first conductive polymer layer 21A is formed inside the pores (recesses) of the dielectric layer 13. The first conductive polymer layer 21A may be formed so as to cover the entire pores of the dielectric layer 13, or the first conductive polymer layer 21A may be formed so as to cover a part of the pores of the dielectric layer 13.

[0128] In the step of forming the first conductive polymer layer 21A, a layer containing the first conductive polymer is formed using a liquid containing the first conductive polymer. The first conductive polymer layer 21A is preferably formed using a liquid in which the first conductive polymer is dissolved.

[0129] The first conductive polymer layer 21A is preferably formed by applying a liquid containing the first conductive polymer. Specifically, the first conductive polymer layer 21A is formed by a method such as applying a liquid containing the first conductive polymer, preferably a liquid in which the first conductive polymer is dissolved, to the surface of the anode plate 10 and drying it. The application and drying may be repeated any number of times depending on the required characteristics, but it is preferably 1 or more and 3 or less times in consideration of resistance to delamination, cost minimization, etc.

[0130] FIG. 7 is a cross-sectional view schematically showing an example of the step of forming the second conductive polymer layer.

[0131] As shown in FIG. 7, a second conductive polymer layer 21B covering the first conductive polymer layer 21A is formed inside the pores (recesses) of the dielectric layer 13. The second conductive polymer layer 21B may be formed so as to cover the entire first conductive polymer layer 21A, or the second conductive polymer layer 21B may be formed so as to cover a part of the first conductive polymer layer 21A. The second conductive polymer layer 21B may be formed so as to fill the pores (recesses) of the dielectric layer 13.

[0132] In the step of forming the second conductive polymer layer 21B, a layer in which the second conductive polymer and the insulating material are mixed is formed using a liquid containing the second conductive polymer and a liquid containing an insulating material having hygroscopicity and containing an OH group, a COOH group, a CO group, or an NH2 group in the molecule and not having a dopant function with respect to the conductive polymer. The second conductive polymer layer 21B is preferably formed using a liquid in which a second conductive polymer having a larger particle size than the first conductive polymer is dispersed and a liquid in which the insulating material is dissolved.

[0133] The particle size of the conductive polymer can be measured by dynamic light scattering (DLS).

[0134] The second conductive polymer layer 21B is preferably formed by simultaneously applying a liquid containing a second conductive polymer and a liquid containing an insulating material. Specifically, the second conductive polymer layer 21B is formed by, for example, simultaneously applying a liquid containing a second conductive polymer, preferably a liquid in which the second conductive polymer is dispersed, and a liquid containing an insulating material, preferably a liquid in which the insulating material is dissolved, onto the surface of the anode plate 10 on which the first conductive polymer layer 21A is formed, and then drying. The coating and drying may be repeated any number of times depending on the required properties. For example, when forming a cathode layer containing a metal or a sealing layer, it is preferably performed 1 to 5 times from the viewpoint of improving the resistance to delamination.

[0135] Note that simultaneously applying a liquid containing a second conductive polymer and a liquid containing an insulating material means applying the other liquid before drying one liquid, and the method thereof is not particularly limited.

[0136] In the method of simultaneously applying a liquid containing a second conductive polymer and a liquid containing an insulating material, even in a combination of materials in which the dispersion stability of the second conductive polymer deteriorates due to the influence of the insulating material, drying and fixing can proceed before the materials aggregate, as compared with the method of mixing the materials in advance.

[0137] FIG. 8 is a perspective view schematically showing an example of the process of forming a third conductive polymer layer. FIG. 9 is an enlarged cross-sectional view of the portion surrounded by the broken line in the anode plate shown in FIG. 8.

[0138] As shown in FIGS. 8 and 9, a third conductive polymer layer 21C covering at least the second conductive polymer layer 21B is formed on the surface of the anode plate 10. The third conductive polymer layer 21C may be formed so as to cover not only the second conductive polymer layer 21B but also the first conductive polymer layer 21A. By forming the third conductive polymer layer 21C, a solid electrolyte layer 21 is formed. In the example shown in FIG. 8, the solid electrolyte layer 21 is formed on the surface of the dielectric layer 13 in the element region divided by the first insulating layer 30.

[0139] In the step of forming the third conductive polymer layer 21C, a layer containing the third conductive polymer is formed using a liquid containing the third conductive polymer. It is preferable to use a liquid containing a binder in addition to the third conductive polymer.

[0140] The third conductive polymer layer 21C is formed, for example, by a method of applying a liquid containing the third conductive polymer to the surface of the anode plate 10 on which the first conductive polymer layer 21A and the second conductive polymer layer 21B are formed and drying it. Alternatively, the third conductive polymer layer 21C may be formed by forming a polymerized film of the third conductive polymer on the surface of the anode plate 10 on which the first conductive polymer layer 21A and the second conductive polymer layer 21B are formed using a liquid containing a monomer such as 3,4-ethylenedioxythiophene.

[0141] In a sheet-like capacitor array having many interfaces of different materials and a thickness dimension smaller than the in-plane dimension, delamination due to stress is likely to occur. Therefore, in order to enhance the anchor effect in the pore portion, it is preferable to minimize the coating amount of the conductive polymer contained in the solid electrolyte layer 21.

[0142] The step of forming the cathode layer 20 preferably further includes a step of forming a conductor layer 22 on the surface of the solid electrolyte layer 21.

[0143] The step of forming the conductor layer 22 includes, for example, a step of forming a first conductor layer 22A on the surface of the solid electrolyte layer 21 and a step of forming a second conductor layer 22B on the surface of the first conductor layer 22A.

[0144] FIG. 10 is a perspective view schematically showing an example of the step of forming the first conductor layer.

[0145] As shown in FIG. 10, a first conductor layer 22A is formed on the surface of the solid electrolyte layer 21. The first conductor layer 22A is, for example, a conductive resin layer containing a conductive filler.

[0146] FIG. 11 is a perspective view schematically showing an example of the step of forming the second conductor layer.

[0147] As shown in FIG. 11, a second conductor layer 22B is formed on the surface of the first conductor layer 22A. Thereby, the conductor layer 22 is formed. The second conductor layer 22B is, for example, a conductive resin layer containing a metal filler. Thus, the step of forming the conductor layer 22 may include a step of forming a conductive resin layer containing a metal filler.

[0148] As an example, the conductor layer 22 includes a carbon layer as the first conductor layer 22A and a copper layer as the second conductor layer 22B.

[0149] FIG. 12 is a perspective view schematically showing an example of the step of dividing the anode plate on which the cathode layer is formed.

[0150] As shown in FIG. 12, the anode plate 10 on which the cathode layer 20 is formed is divided to separate the element regions, thereby separating into a plurality of solid electrolytic capacitors 110.

[0151] Examples of the method of dividing the anode plate 10 on which the cathode layer 20 is formed include laser processing, dicing processing, and the like.

[0152] As shown in FIG. 12, it is preferable to divide the anode plate 10 between at least one pair of adjacent solid electrolytic capacitors 110 among the plurality of solid electrolytic capacitors 110. That is, it is preferable to divide the anode plate 10 so as to penetrate in the thickness direction between at least one pair of adjacent solid electrolytic capacitors 110.

[0153] When forming the first insulating layer 31, through-hole conductors 61 and 62 penetrating in the thickness direction of the first insulating layer 31 may be formed. For example, the through-hole conductor 61 may be formed inside the first through-hole 71, and the through-hole conductor 62 may be formed inside the second through-hole 72.

[0154] FIG. 13 is a perspective view schematically showing an example of the process of forming the second through-hole.

[0155] As shown in FIG. 13, if necessary, a second through-hole 72 penetrating in the thickness direction of the first insulating layer 31 is formed.

[0156] Examples of the method of forming the second through-hole 72 include laser processing and drill processing.

[0157] FIG. 14 is a perspective view schematically showing an example of the process of forming the sealing layer.

[0158] As shown in FIG. 14, for example, by providing an insulating material by pressing or the like, a sealing layer 120 is formed so as to cover the plurality of solid electrolytic capacitors 110. The sealing layer 120 is formed so as to cover the cathode layer 20, the first insulating layer 30, and the first insulating layer 31. The sealing layer 120 is preferably formed so as to cover all of the outer peripheral portions of the solid electrolytic capacitor 110, that is, so as to cover the top, bottom, left, and right of the solid electrolytic capacitor 110.

[0159] By forming the sealing layer 120, the sealing layer 120 may be filled between adjacent solid electrolytic capacitors 110. The sealing layer 120 surely divides the anode plates 10 from each other.

[0160] Also, when the second through hole 72 is formed, the second through hole 72 may be filled with the sealing layer 120.

[0161] FIG. 15 is a perspective view schematically showing an example of the process of forming the first through hole.

[0162] As shown in FIG. 15, if necessary, a first through hole 71 penetrating the first insulating layer 31 in the thickness direction is formed. The hole diameter of the first through hole 71 is smaller than the hole diameter of the second through hole 72.

[0163] Examples of the method for forming the first through hole 71 include laser processing and drilling.

[0164] As shown in FIG. 15, further, a third through hole 73 having a smaller hole diameter than the second through hole 72 may be formed. The hole diameter of the third through hole 73 may be the same as the hole diameter of the first through hole 71, may be larger than the hole diameter of the first through hole 71, or may be smaller than the hole diameter of the first through hole 71.

[0165] Examples of the method for forming the third through hole 73 include laser processing and drilling.

[0166] FIG. 16 is a perspective view schematically showing an example of the process of forming the through hole conductor.

[0167] As shown in FIG. 16, a through hole conductor 61 is formed inside the first through hole 71, and a through hole conductor 62 is formed inside the second through hole 72.

[0168] The through hole conductor 61 is formed so as to penetrate the solid electrolytic capacitor 110 and the sealing layer 120 in the thickness direction. The through hole conductor 61 is preferably electrically connected to the end face of the anode plate 10 of the solid electrolytic capacitor 110 at the inner wall of the first through hole 71 (that is, the side wall of the through hole conductor 61). In the example shown in FIG. 16, the through hole conductor 61 is formed so as to fill the first through hole 71, but the through hole conductor 61 only needs to be formed on at least the inner wall surface of the first through hole 71.

[0169] The through-hole conductor 62 is formed so as to penetrate the solid electrolytic capacitor 110 and the sealing layer 120 in the thickness direction. The through-hole conductor 62 is preferably electrically insulated from the anode plate 10 of the solid electrolytic capacitor 110 on the inner wall of the second through-hole 72 (that is, the side wall of the through-hole conductor 62). In the example shown in FIG. 16, the through-hole conductor 62 is formed so as to fill the third through-hole 73, but the through-hole conductor 62 may be formed on at least the inner wall surface of the third through-hole 73.

[0170] As shown in FIG. 16, the sealing layer 120 may be filled between the through-hole conductor 62 and the anode plate 10. The sealing layer 120 surely insulates the through-hole conductor 62 from the anode plate 10 on the inner wall of the second through-hole 72.

[0171] FIG. 17 is a perspective view schematically showing an example of a process for forming a via conductor.

[0172] As shown in FIG. 17, the via conductor 50 may be formed in the sealing layer 120.

[0173] Thereafter, by forming a first external electrode 41 and a second external electrode 42 (not shown), the capacitor array 100 shown in FIG. 1 can be manufactured.

[0174] As described above, when manufacturing the capacitor array 100, examples of the method for dividing the anode plate 10 on which the cathode layer 20 is formed include laser processing and dicing processing. Among them, by using laser processing, the element region can be formed in a free shape. Therefore, it is possible to arrange two or more types of solid electrolytic capacitors 110 having different element region areas in one capacitor array 100, to arrange slits so as not to cover the entire capacitor array 100, to arrange a solid electrolytic capacitor 110 in which the planar shape of the cathode layer 20 is not rectangular, and the like.

[0175] FIG. 18 is a cross-sectional view schematically showing another example of the capacitor array of the present invention. FIG. 19 is an enlarged cross-sectional view of a portion surrounded by a broken line in the capacitor array shown in FIG. 18.

[0176] The capacitor array 100A shown in FIG. 18 further includes a second insulating layer 32 provided inside the pores of the dielectric layer 13 so as to cover a part of the solid electrolyte layer 21. Except for this point, the capacitor array 100A shown in FIG. 18 has the same configuration as the capacitor array 100 shown in FIG. 1.

[0177] The second insulating layer 32 is preferably provided so as to cover a part of the solid electrolyte layer 21 located in the vicinity of the first insulating layer 30 or 31. That is, the second insulating layer 32 is preferably provided so as to cover the end of the solid electrolyte layer 21. When both the first insulating layers 30 and 31 are provided, the second insulating layer 32 may be provided so as to cover both a part of the solid electrolyte layer 21 located in the vicinity of the first insulating layer 30 and a part of the solid electrolyte layer 21 located in the vicinity of the first insulating layer 31, or the second insulating layer 32 may be provided so as to cover either one of them.

[0178] The second insulating layer 32 may be provided so as to extend from the solid electrolyte layer 21 and cover the whole or a part of the first insulating layer 30. Similarly, the second insulating layer 32 may be provided so as to extend from the solid electrolyte layer 21 and cover the whole or a part of the first insulating layer 31.

[0179] Around the first insulating layer 30, the wettability between the solid electrolyte layer 21 and the first insulating layer 30 is poor, so the formation rate of the solid electrolyte layer 21 tends to decrease. The same is true around the first insulating layer 31. The state where there is a conductive polymer but the solid electrolyte layer 21 is not formed is not a preferable state in mechanisms such as expansion due to moisture intrusion and capacitance fluctuation. Therefore, by forming the second insulating layer 32 inside the pores of the dielectric layer 13 so as to cover a part of the solid electrolyte layer 21, expansion can be physically suppressed.

[0180] In particular, when a plurality of solid electrolytic capacitors 110 are present inside the sealing layer 120, such as in the capacitor array 100A, the ratio of the surface areas of the first insulating layers 30 and 31 increases, so the influence of capacitance variation due to a decrease in the formation rate of the solid electrolyte layer 21 becomes significant. Therefore, forming the second insulating layer 32 is an effective means.

[0181] On the other hand, if the range where the second insulating layer 32 is provided is too wide, the conductive path itself is damaged, leading to an increase in resistance. Therefore, it is preferable that the second insulating layer 32 is provided in a range of 1 μm or more and 100 μm or less from the edge of the first insulating layer 30 or 31 toward the solid electrolyte layer 21.

[0182] The second insulating layer 32 contains an insulating material.

[0183] The second insulating layer 32 is preferably made of resin. Examples of the resin constituting the second insulating layer 32 include insulating resins such as polyphenylsulfone resin, polyethersulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene·perfluoroalkyl vinyl ether copolymer, etc.), polyimide resin, polyamideimide resin, epoxy resin, and their derivatives or precursors. The second insulating layer 32 may be composed of the same resin as the first insulating layer 30 or 31, or may be composed of a different resin.

[0184] Since including an inorganic filler in the second insulating layer 32 may have an adverse effect on the effective part of the solid electrolytic capacitor 110, the second insulating layer 32 preferably consists of a resin-only system.

[0185] The second insulating layer 32 can be formed, for example, by applying a mask material such as a composition containing an insulating resin to cover a part of the solid electrolyte layer 21 by methods such as sponge transfer, screen printing, dispenser coating, inkjet printing, etc.

[0186] The second insulating layer 32 is preferably filled inside the pores of the dielectric layer 13. The second insulating layer 32 may be provided on the surface of the anode plate 10.

[0187] The capacitor array 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 array of the present invention, external electrodes provided outside the capacitor array and connected to the anode plate and the cathode layer of the solid electrolytic capacitor, respectively, and an electronic component connected to the external electrodes.

[0188] In the composite electronic component, the electronic component connected to the external electrode may be a passive element or an active element. Both the passive element and the active element may be connected to the external electrode, or either the passive element or the active element may be connected to the external electrode. Further, a composite of the passive element and the active element may be connected to the external electrode.

[0189] Examples of the passive element include an inductor. Examples of the active element include a memory, a GPU (Graphical Processing Unit), a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a PMIC (Power Management IC), and the like.

[0190] The capacitor array of the present invention has a sheet-like shape as a whole. Therefore, in the composite electronic component, the capacitor array can be treated like a mounting substrate, and electronic components can be mounted on the capacitor array. Further, by forming the shape of the electronic component to be mounted on the capacitor array into a sheet shape, it is also possible to connect the capacitor array and the electronic component in the thickness direction through a through-hole conductor that penetrates each electronic component in the thickness direction. As a result, the active element and the passive element can be configured like an integrated module.

[0191] For example, the capacitor array of the present invention can be electrically connected between a voltage regulator including a semiconductor active element and a load to which a converted DC voltage is supplied to form a switching regulator.

[0192] In a composite electronic component, after forming a circuit layer on one surface of a capacitor matrix sheet in which a plurality of capacitor arrays of the present invention are further laid out, it may be connected to a passive element or an active element.

[0193] Alternatively, the capacitor array of the present invention may be disposed in a cavity portion provided in a substrate in advance, embedded with resin, and then a circuit layer may be formed on the resin. Another electronic component (passive element or active element) may be mounted in another cavity portion of the same substrate.

[0194] Or, the capacitor array of the present invention may be mounted on a smooth carrier such as a wafer or glass, an outer layer portion made of resin is formed, and then a circuit layer is formed and may be connected to a passive element or an active element.

[0195] The following contents are disclosed in this specification.

[0196] <1> An anode plate having a core portion, a porous layer provided on at least one main surface of the core portion, and a dielectric layer provided on the surface of the porous layer, 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, The solid electrolyte layer includes a conductive polymer layer in which a conductive polymer and an insulating material are mixed inside the pores of the dielectric layer, The insulating material is a material that contains an OH group, a COOH group, a CO group, or an NH2 group in the molecule, has hygroscopicity, and does not have a doping function with respect to the conductive polymer, a solid electrolytic capacitor.

[0197] <2> The solid electrolytic capacitor according to <1>, further comprising a first insulating layer provided in a region where the cathode layer is not formed on the surface of the porous layer.

[0198] <3> The solid electrolytic capacitor according to <2>, further comprising a second insulating layer provided inside the pores of the dielectric layer so as to cover a part of the solid electrolyte layer.

[0199] <4> The solid electrolytic capacitor according to <3>, wherein the second insulating layer is provided in a range of 1 μm or more and 100 μm or less from the end of the first insulating layer toward the solid electrolyte layer.

[0200] <5> The solid electrolytic capacitor according to any one of <2> to <4>, wherein the first insulating layer is provided so as to surround the cathode layer when viewed in the thickness direction.

[0201] <6> The solid electrolytic capacitor according to any one of <2> to <4>, wherein the first insulating layer is provided inside the cathode layer when viewed in the thickness direction.

[0202] <7> A sealing layer provided so as to cover the solid electrolytic capacitor, A first external electrode and a second external electrode provided outside the sealing layer, A via conductor provided inside the sealing layer, Further comprising a through-hole conductor provided so as to penetrate the sealing layer in the thickness direction, The side wall of the through-hole conductor is electrically connected to the end face of the anode plate of the solid electrolytic capacitor, The first external electrode is electrically connected to the anode plate of the solid electrolytic capacitor through the through-hole conductor, The second external electrode is electrically connected to the cathode layer of the solid electrolytic capacitor through the via conductor. The solid electrolytic capacitor according to any one of <1> to <6>.

[0203] <8> A solid electrolytic capacitor according to any one of <1> to <6>, and A sealing layer provided so as to cover the solid electrolytic capacitor, and A first external electrode and a second external electrode provided outside the sealing layer, and A via conductor provided inside the sealing layer, and A through-hole conductor provided so as to penetrate the sealing layer in the thickness direction, and Two or more of the solid electrolytic capacitors are present inside the sealing layer, The side wall of the through-hole conductor is electrically connected to the end face of the anode plate of the solid electrolytic capacitor, The first external electrode is electrically connected to the anode plate of the solid electrolytic capacitor through the through-hole conductor, The second external electrode is electrically connected to the cathode layer of the solid electrolytic capacitor through the via conductor. Capacitor array.

[0204] <9> The capacitor array according to <8>, wherein the space between adjacent solid electrolytic capacitors is filled with the same material as the sealing layer.

Example

[0205] Hereinafter, examples specifically disclosing the solid electrolytic capacitor and the capacitor array of the present invention will be shown. Note that the present invention is not limited only to these examples.

[0206] (Example 1) In Example 1, a capacitor array 100 shown in FIG. 1 was manufactured.

[0207] An aluminum sheet having a porous layer and an oxide film on both sides was prepared, and using an insulating resin, a mask layer (first insulating layer) surrounding the effective part (element region) that becomes the capacitance part of the solid electrolytic capacitor, and an insulating support layer (first insulating layer) for forming a through-hole conductor in the effective part were formed by coating. After applying a conductive polymer ink in which a conductive polymer represented by poly(3,4-ethylenedioxythiophene) and soluble in a solvent was dissolved to the formed effective part, a process of drying was performed a plurality of times to form a first conductive polymer layer on the surface of the dielectric layer.

[0208] Next, a process of simultaneously applying a dispersion in which a second conductive polymer different from the first conductive polymer was dispersed and a solution in which an insulating material having hygroscopicity and having no dopant function with respect to the conductive polymer contained in the solid electrolyte layer was dissolved, and then drying was performed a plurality of times to form a second conductive polymer layer in which the insulating material was mixed in the continuous conductive region. As the second conductive polymer, a conductive polymer represented by poly(3,4-ethylenedioxythiophene), having a larger particle size than the first conductive polymer, insoluble in a solvent but having high heat resistance was used. As the insulating material, a phenolic material having hygroscopicity was used.

[0209] Subsequently, a third conductive polymer layer was formed by applying a third conductive polymer to the effective part to form a solid electrolyte layer. Thereafter, as the conductor layer, a first conductor layer and a second conductor layer were each formed by coating. A carbon layer was formed as the first conductor layer, and a copper layer was formed as the second conductor layer. Thus, a solid electrolytic capacitor sheet was obtained.

[0210] Resin sheets were pasted on the upper and lower surfaces of the obtained solid electrolytic capacitor sheet and pressure-bonded at a temperature above the glass transition point to obtain a capacitor array sheet having a smooth surface.

[0211] After cutting the capacitor array sheet so that each solid electrolytic capacitor was independent, the formed grooves (slits) were filled by again pressure-bonding the resin sheet at a temperature above the glass transition point.

[0212] Holes were formed from the sealing layer composed of a resin sheet toward the second conductor layer, and the inside of the formed holes was filled with a conductive material, thereby forming via conductors serving as the cathode lead electrodes.

[0213] Also, through holes were formed in the insulating support layer (first insulating layer), and plating treatment was performed on the formed through holes and the wall surfaces of the exposed aluminum sheets, thereby forming through-hole conductors serving as the anode lead electrodes.

[0214] The capacitor array sheet obtained as described above was cut and separated into individual pieces, thereby obtaining the solid electrolytic capacitor of Example 1.

[0215] In the solid electrolytic capacitor of Example 1, it is possible to suppress the change in capacitance due to moisture absorption and swelling by the swelling of the insulating material.

[0216] (Example 2) In Example 2, a capacitor array 100A shown in FIG. 18 was fabricated.

[0217] An aluminum sheet having porous layers and oxide films on both sides was prepared, and using an insulating resin, a mask layer (first insulating layer) surrounding the effective portion (element region) serving as the capacitance portion of the solid electrolytic capacitor and an insulating support layer (first insulating layer) for forming through-hole conductors in the effective portion were formed by coating. A process in which a conductive polymer ink in which a conductive polymer represented by poly(3,4-ethylenedioxythiophene) and soluble in a solvent was dissolved was applied to the formed effective portion and then dried was performed a plurality of times to form a first conductive polymer layer on the surface of the dielectric layer.

[0218] Next, a process is repeatedly performed in which a dispersion liquid in which a second conductive polymer different from the first conductive polymer is dispersed and a solution in which an insulating material having hygroscopicity and having no dopant function with respect to the conductive polymer contained in the solid electrolyte layer is dissolved are simultaneously applied and then dried, to form a second conductive polymer layer in which the insulating material is mixed while the conductive regions are continuous. As the second conductive polymer, a conductive polymer represented by poly(3,4-ethylenedioxythiophene), which has a larger particle size than the first conductive polymer, is insoluble in a solvent, but has high heat resistance, was used. As the insulating material, a phenolic material having hygroscopicity was used.

[0219] Subsequently, a third conductive polymer layer was formed by applying a third conductive polymer to the active portion, thereby forming a solid electrolyte layer. When forming the solid electrolyte layer, in order to suppress the risk of short circuit due to direct contact between the aluminum sheet and the conductor layer described later, a liquid having a higher viscosity than the liquid used to form the first conductive polymer layer and the second conductive polymer layer was used, and the aluminum sheet was applied so as not to be exposed on the surface.

[0220] After forming the solid electrolyte layer, a second insulating layer was formed by expanding the coating area 50 μm toward the active portion side from the mask layer (first insulating layer) and the insulating support layer (first insulating layer) and applying an insulating resin.

[0221] Thereafter, as the conductor layer, a first conductor layer and a second conductor layer were each formed by coating. A carbon layer was formed as the first conductor layer, and a copper layer was formed as the second conductor layer. Thus, a solid electrolytic capacitor sheet was obtained.

[0222] Resin sheets were pasted on the upper and lower surfaces of the obtained solid electrolytic capacitor sheet and pressure-bonded at a temperature equal to or higher than the glass transition point, thereby obtaining a capacitor array sheet having a smooth surface.

[0223] After cutting the capacitor array sheet so that each solid electrolytic capacitor is independent, the formed grooves (slits) were filled by pressing the resin sheet again at a temperature above the glass transition point.

[0224] Holes were formed from the sealing layer composed of the resin sheet toward the second conductor layer, and the inside of the formed holes was filled with a conductive material to form via conductors serving as the cathode extraction electrodes.

[0225] Also, through holes were formed in the insulating support layer (first insulating layer), and plating treatment was performed on the formed through holes and the wall surfaces of the exposed aluminum sheets to form through-hole conductors serving as the anode extraction electrodes.

[0226] By cutting and fragmenting the capacitor array sheet obtained above, the solid electrolytic capacitor of Example 2 was obtained.

[0227] In the solid electrolytic capacitor of Example 2, in addition to Example 1, by filling the vicinity of the mask layer with an insulating resin, a state where physical swelling cannot occur can be created. However, if the entire surface is filled, the conductivity decreases, so it is preferable to selectively fill only the vicinity of the mask layer.

[0228] (Comparative Example 1) In Comparative Example 1, a capacitor array 100B shown in FIG. 20 was fabricated.

[0229] FIG. 20 is a cross-sectional view schematically showing an example of the capacitor array of Comparative Example 1. FIG. 21 is an enlarged cross-sectional view of the portion surrounded by the broken line in the capacitor array shown in FIG. 20.

[0230] An aluminum sheet having porous layers and an oxide film on both sides was prepared, and using an insulating resin, a mask layer (first insulating layer) surrounding the effective portion (element region) that becomes the capacitance portion of the solid electrolytic capacitor, and an insulating support layer (first insulating layer) for forming a through-hole conductor within the effective portion were formed by coating. A process of drying after applying a dispersion liquid in which a second conductive polymer was dispersed to the formed effective portion was performed a plurality of times to form a first conductive polymer layer on the surface of the dielectric layer.

[0231] Subsequently, a third conductive polymer layer was formed in the effective portion to form a solid electrolyte layer. Thereafter, as the conductor layers, a first conductor layer and a second conductor layer were each formed by coating. A carbon layer was formed as the first conductor layer, and a copper layer was formed as the second conductor layer. Thus, a solid electrolytic capacitor sheet was obtained.

[0232] Resin sheets were pasted on the upper and lower surfaces of the obtained solid electrolytic capacitor sheet and pressure-bonded at a temperature above the glass transition point to obtain a capacitor array sheet with a smooth surface.

[0233] After cutting the capacitor array sheet so that each solid electrolytic capacitor was independent, the formed grooves (slits) were filled by again pressure-bonding a resin sheet at a temperature above the glass transition point.

[0234] Holes were formed from the sealing layer composed of the resin sheet toward the second conductor layer, and the inside of the formed holes was filled with a conductive material to form via conductors that serve as the cathode extraction electrodes.

[0235] Also, through-holes were formed in the insulating support layer (first insulating layer), and a through-hole conductor that serves as the anode extraction electrode was formed by performing plating on the formed through-holes and the wall surfaces of the exposed aluminum sheet.

[0236] The capacitor array sheet obtained as described above was cut and fragmented to obtain the solid electrolytic capacitor of Comparative Example 1.

[0237] For the solid electrolytic capacitors of Example 2 and Comparative Example 1, with the measured values after leaving them standing in an atmosphere of 22°C and 60% humidity for 48 hours as a reference, the capacitance change rate (ΔCap) was measured when only the humidity was changed and they were left standing for 48 hours.

[0238] FIG. 22 is a graph showing the relationship between humidity and capacitance change rate in the solid electrolytic capacitors of Example 2 and Comparative Example 1.

[0239] From FIG. 22, it can be seen that in the solid electrolytic capacitor of Example 2, the capacitance change rate in a high-humidity environment is suppressed as compared with the solid electrolytic capacitor of Comparative Example 1.

Explanation of Reference Numerals

[0240] 10 Anode plate 11 Core part 12 Porous layer 13 Dielectric layer 20 Cathode layer 21 Solid electrolyte layer 21A First conductive polymer layer 21B Second conductive polymer layer 21C Third conductive polymer layer 22 Conductor layer 22A First conductor layer 22B Second conductor layer 30, 31 First insulating layer 32 Second insulating layer 41 First external electrode 42 Second external electrode 50 Via conductor 61, 62 Through-hole conductor 71 First through-hole 72 Second through-hole 73 Third through-hole 100, 100A, 100B Capacitor array 110 Solid electrolytic capacitor 120 Sealing layer

Claims

1. An anode plate having a core portion, a porous layer provided on at least one main surface of the core portion, and a dielectric layer provided on the surface of the porous layer, 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 the solid electrolyte layer includes a conductive polymer layer in which a conductive polymer and an insulating material are mixed inside the pores of the dielectric layer. The insulating material contains an OH group, a COOH group, a CO group or an NH group in the molecule, has hygroscopicity, and is a material that does not have a doping function with respect to the conductive polymer, a solid electrolytic capacitor. ２ A solid electrolytic capacitor which is a material that contains a group and has hygroscopicity and does not have a doping function with respect to the conductive polymer.

2. The solid electrolytic capacitor according to claim 1, further comprising a first insulating layer provided in a region where the cathode layer is not formed on the surface of the porous layer.

3. The solid electrolytic capacitor according to claim 2, further comprising a second insulating layer provided inside the pores of the dielectric layer so as to cover a part of the solid electrolyte layer.

4. The solid electrolytic capacitor according to claim 3, wherein the second insulating layer is provided in a range of 1 μm or more and 100 μm or less from the end of the first insulating layer toward the solid electrolyte layer.

5. The solid electrolytic capacitor according to any one of claims 2 to 4, wherein the first insulating layer is provided so as to surround the cathode layer when viewed from the thickness direction.

6. The solid electrolytic capacitor according to any one of claims 2 to 4, wherein the first insulating layer is provided inside the cathode layer when viewed from the thickness direction.

7. A sealing layer provided so as to cover the solid electrolytic capacitor, a first external electrode and a second external electrode provided outside the sealing layer, a via conductor provided inside the sealing layer, and a through-hole conductor provided so as to penetrate the sealing layer in the thickness direction, wherein the through-hole conductor is electrically connected to an end surface of the anode plate of the solid electrolytic capacitor at its side wall, the first external electrode is electrically connected to the anode plate of the solid electrolytic capacitor via the through-hole conductor, and the second external electrode is electrically connected to the cathode layer of the solid electrolytic capacitor via the via conductor. The solid electrolytic capacitor according to any one of claims 1 to 4.

8. A solid electrolytic capacitor according to any one of claims 1 to 4, a sealing layer provided so as to cover the solid electrolytic capacitor, a first external electrode and a second external electrode provided outside the sealing layer, a via conductor provided inside the sealing layer, and a through-hole conductor provided so as to penetrate the sealing layer in the thickness direction. Inside the sealing layer, there are two or more of the solid electrolytic capacitors. The through-hole conductor is electrically connected to an end face of the anode plate of the solid electrolytic capacitor at its side wall. The first external electrode is electrically connected to the anode plate of the solid electrolytic capacitor via the through-hole conductor. The second external electrode is electrically connected to the cathode layer of the solid electrolytic capacitor via the via conductor, capacitor array.

9. The capacitor array according to claim 8, wherein a space between adjacent ones of the solid electrolytic capacitors is filled with the same material as the sealing layer.

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