Solid electrolytic capacitor and method for manufacturing the same

Abstract

To provide a solid electrolytic capacitor in which a cathode portion is reliably insulated from an anode portion, and a method of manufacturing the same.SOLUTION: A solid electrolytic capacitor 1 includes: an anode plate 11 made of a valve action metal; a porous layer 12 provided on at least one principal surface of the anode plate 11; a dielectric layer 13 provided on a surface of the porous layer 12; an insulating layer 14 filled inside the porous layer 12 and provided on a surface of the porous layer 12 on a filled portion; and a cathode layer 15 including a solid electrolyte layer 15A provided on a surface of the dielectric layer 13. The cathode layer 15 is divided into two or more cathode portions 16. The insulating layer 14 includes a first insulating layer 14A surrounding at least one of the cathode portions 16 as viewed in a thickness direction. A first penetrating section 17A that penetrates through both of the porous layer 12 and the first insulating layer 14A in the thickness direction is formed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a solid electrolytic capacitor and a method for manufacturing a solid electrolytic capacitor. [Background technology]

[0002] The solid electrolytic capacitor includes an anode plate made of a valve metal such as aluminum, with a dielectric layer provided on the surface of a porous layer, and a cathode layer including a solid electrolyte layer provided on the surface of the dielectric layer.

[0003] In order to manufacture a high-performance solid electrolytic capacitor, it is important to ensure electrical insulation between the part of the anode plate where no solid electrolyte layer is provided (anode part) and the part of the cathode layer where a solid electrolyte layer is provided (cathode part).

[0004] Patent Document 1 discloses a method for manufacturing a solid electrolytic capacitor in which a solid electrolyte is formed at a desired position on a metal material having a dielectric film and valve action, the method comprising the step of applying a masking material solution that penetrates into the dielectric film and forms a masking layer on the penetrated portion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4623404 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the method for manufacturing a solid electrolytic capacitor described in Patent Document 1, the masking material penetrates into the dielectric film and is formed on the penetration portion, so that the solid electrolyte cannot penetrate into the dielectric film penetrated by the masking material, and the solid electrolyte is masked by the masking material formed on the penetration portion, thereby ensuring insulation between the cathode and anode portions.

[0007] Patent Document 1 describes that it is difficult to apply the masking material in a uniform line all around the periphery of the substrate with the following methods (1) to (3). (1) A method of applying a masking material in a thin string-like state, for example, by dropping the masking material directly onto the surface of the substrate (aluminum chemical foil) using a dispenser, etc. (2) Applying the paint to the surface of aluminum foil using a brush, a thin stick such as a bamboo skewer, etc. (3) A method of screen printing a masking material onto aluminum foil.

[0008] Furthermore, Patent Document 1 describes that the masking material was successfully applied in a uniform line around the entire circumference of a desired portion of a substrate by the following steps (1) to (5). (1) Fix one end of multiple chemical foils (substrates) in a strip shape to a table (metal guide) that moves linearly. (2) The smooth top surface (coating surface) of the rotating disc-shaped roll is arranged so as to come into contact with the back surface (lower side) of the substrate fixed to the metal guide with a constant force. (3) The supply of the masking material to the coating surface of the roll should be carried out in a closed system by storing a solution containing the masking material in a sealed container and using a fixed-volume coating liquid supplying device such as a constant-volume dispenser with little pulsation, via a resin tube, needle, etc. (4) Pressing a roll onto the chemical foil, the solution containing the masking material being evenly applied to the circumferential portion of the application surface, and applying the masking material to the underside and side surfaces of the chemical foil substrate by adjusting the running speed of the metal plate guide and the rotation speed of the rotating roll. (5) After the roll coated with the solution containing the masking material comes into contact with the chemical foil substrate, a means for removing and cleaning the masking material remaining on the coated surface of the roll until a new coating solution is applied is provided.

[0009] As mentioned above, Patent Document 1 describes a method in which a chemically processed foil cut into the shape of a capacitor element is fixed to a metal guide and a masking material is applied by roll transfer. However, when manufacturing an array-shaped solid electrolytic capacitor in which the cathode layer is divided into two or more cathode portions, the method of applying a masking material by roller transfer to separate the multiple capacitor element portions is inappropriate. Furthermore, depending on the shape of the capacitor element portion, the masking material may need to be applied discontinuously, but applying the masking material discontinuously using the roller transfer method is difficult.

[0010] An object of the present invention is to provide a solid electrolytic capacitor in which, when a cathode layer is divided into two or more cathode portions, each cathode portion is reliably insulated from an anode portion. Another object of the present invention is to provide a method for manufacturing a solid electrolytic capacitor in which, when a cathode layer is divided into two or more cathode portions, each cathode portion is reliably insulated from an anode portion. [Means for solving the problem]

[0011] The solid electrolytic capacitor of the present invention includes an anode plate made of a valve metal, a porous layer provided on at least one main surface of the anode plate, a dielectric layer provided on the surface of the porous layer, an insulating layer filled inside the porous layer and provided on the surface of the porous layer above the filled portion, and a cathode layer including a solid electrolyte layer provided on the surface of the dielectric layer. The cathode layer is divided into two or more cathode portions. The insulating layer includes a first insulating layer surrounding at least one of the cathode portions when viewed in the thickness direction. A first penetrating portion is formed so as to penetrate both the porous layer and the first insulating layer in the thickness direction.

[0012] A method for manufacturing a solid electrolytic capacitor according to the present invention includes the steps of: forming an insulating layer on an anode plate made of a valve metal, the anode plate having a porous layer on at least one main surface thereof and a dielectric layer on the surface of the porous layer, so as to fill the interior of the porous layer and on the surface of the porous layer above the filled portion; and forming a cathode layer including a solid electrolyte layer on the surface of the dielectric layer. The step of forming the insulating layer includes the step of forming a first insulating layer surrounding at least one of the element regions in the thickness direction so as to divide the anode plate into two or more element regions. The cathode layer is formed within each of the element regions so as to divide the anode plate into two or more cathode portions. The method for manufacturing a solid electrolytic capacitor according to the present invention further includes the step of forming a first penetrating portion penetrating both the porous layer and the first insulating layer in the thickness direction. [Effects of the Invention]

[0013] According to the present invention, when a cathode layer is divided into two or more cathode portions, it is possible to provide a solid electrolytic capacitor in which each cathode portion is reliably insulated from an anode portion.Furthermore, when a cathode layer is divided into two or more cathode portions, it is possible to provide a method for manufacturing a solid electrolytic capacitor in which each cathode portion is reliably insulated from an anode portion. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view schematically illustrating an example of a solid electrolytic capacitor of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 1 taken along line II-II. [Figure 3] FIG. 3 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 1 taken along line III-III. [Figure 4] FIG. 4 is a perspective view schematically showing a capacitor layer that constitutes the solid electrolytic capacitor shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV of the capacitor layer shown in FIG. [Figure 6]FIG. 6 is a cross-sectional view taken along line VI-VI of the capacitor layer shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a first through-hole conductor and its periphery in another example of the solid electrolytic capacitor of the present invention. [Figure 8] FIG. 8 is a cross-sectional view schematically showing the second through-hole conductor and its periphery in the solid electrolytic capacitor shown in FIG. [Figure 9] FIG. 9 is a perspective view schematically showing an example of a step of forming an insulating layer on an anode plate. [Figure 10] FIG. 10 is a perspective view schematically illustrating an example of a step of forming a cathode layer. [Figure 11] FIG. 11 is a perspective view schematically illustrating an example of a step of forming a first penetrating portion. [Figure 12] FIG. 12 is a perspective view schematically illustrating an example of a step of forming a second through hole, among the steps of forming the second penetrating portion. [Figure 13] FIG. 13 is a perspective view schematically illustrating an example of a step of forming a sealing layer. [Figure 14] FIG. 14 is a perspective view schematically illustrating an example of a step of forming a first through hole, among the steps of forming a second through portion. [Figure 15] FIG. 15 is a perspective view schematically showing an example of a step of forming a through-hole conductor. DETAILED DESCRIPTION OF THE INVENTION

[0015] The solid electrolytic capacitor and the method for manufacturing the solid electrolytic capacitor of the present invention will be described below. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied within the scope of the present invention. Note that the present invention also includes a combination of two or more of the individual desirable configurations of the present invention described below.

[0016] [Solid electrolytic capacitor] Fig. 1 is a perspective view schematically showing an example of a solid electrolytic capacitor of the present invention. Fig. 2 is a cross-sectional view taken along line II-II of the solid electrolytic capacitor shown in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III of the solid electrolytic capacitor shown in Fig. 1.

[0017] 1, 2, and 3 includes a capacitor layer 10. The solid electrolytic capacitor 1 may further include a sealing layer 20, as shown in FIGS.

[0018] Fig. 4 is a perspective view schematically showing a capacitor layer constituting the solid electrolytic capacitor shown in Fig. 1. Fig. 5 is a cross-sectional view taken along line VV of the capacitor layer shown in Fig. 4. Fig. 6 is a cross-sectional view taken along line VI-VI of the capacitor layer shown in Fig. 4.

[0019] 1, 2, and 3, the capacitor layer 10 includes an anode plate 11, a porous layer 12 provided on at least one main surface of the anode plate 11, a dielectric layer 13 provided on the surface of the porous layer 12, an insulating layer 14 filled inside the porous layer 12 and provided on the surface of the porous layer 12 above the filled portion, and a cathode layer 15 provided on the surface of the dielectric layer 13, as shown in FIGS. 4, 5, and 6. The cathode layer 15 includes, for example, a solid electrolyte layer 15A provided on the surface of the dielectric layer 13 and a conductor layer 15B provided on the surface of the solid electrolyte layer 15A. The solid electrolytic capacitor 1 may include only the capacitor layer 10 without the sealing layer 20.

[0020] The cathode layer 15 is divided into two or more cathode portions 16. Of the cathode portions 16, one pair of adjacent first and second cathode portions 16A and 16B is shown in Figures 1, 2, 4, and 5.

[0021] The insulating layer 14 includes a first insulating layer 14A that surrounds at least one cathode portion 16 when viewed in the thickness direction. In Figures 1 and 4, the first insulating layer 14A is provided so as to surround the first cathode portion 16A and the second cathode portion 16B.

[0022] In the solid electrolytic capacitor 1 or the capacitor layer 10, a first penetration portion 17A is formed to penetrate both the porous layer 12 and the first insulating layer 14A in the thickness direction. As shown in Fig. 2 or 5, the first penetration portion 17A may penetrate the anode plate 11 in the thickness direction. That is, the first penetration portion 17A may penetrate the capacitor layer 10 in the thickness direction.

[0023] The anode plate 11 may be divided between at least one pair of adjacent first and second cathode portions 16A and 16B in the cathode portion 16. Specifically, the anode plate 11 may be physically divided or electrically divided between at least one pair of adjacent first and second cathode portions 16A and 16B in the cathode portion 16. For example, as shown in FIG. 2 or 5, the anode plate 11 may be divided between the first and second cathode portions 16A and 16B by a first penetrating portion 17A penetrating the anode plate 11 in the thickness direction.

[0024] The insulating layer 14 may further include a second insulating layer 14B provided in the cathode portion 16 surrounded by the first insulating layer 14A. In this case, the second insulating layer 14B needs to be provided in at least one cathode portion 16. In FIGS. 1 and 4, the second insulating layer 14B is provided in the first cathode portion 16A and the second cathode portion 16B.

[0025] When the insulating layer 14 includes the second insulating layer 14B, the second penetrating portion 17B may be formed so as to penetrate both the porous layer 12 and the second insulating layer 14B in the thickness direction. As shown in Fig. 3 or 6, the second penetrating portion 17B may penetrate the anode plate 11 in the thickness direction. That is, the second penetrating portion 17B may penetrate the capacitor layer 10 in the thickness direction.

[0026] A through-hole conductor 18 extending in the thickness direction is preferably formed inside the second penetrating portion 17B. As shown in Fig. 3, the through-hole conductor 18 is preferably provided so as to penetrate the capacitor layer 10 and the sealing layer 20 in the thickness direction.

[0027] As shown in Figures 1, 3, 4 and 6, the second through portion 17B may be formed as a first through hole 17Ba and a second through hole 17Bb having a larger diameter than the first through hole 17Ba.

[0028] It is preferable that a first through-hole conductor 18A extending in the thickness direction is formed inside first through hole 17Ba. In Fig. 3, first through-hole conductor 18A is provided so as to penetrate capacitor layer 10 and sealing layer 20 in the thickness direction. As shown in Fig. 3, first through-hole conductor 18A is preferably electrically connected to anode plate 11 on the inner wall of first through hole 17Ba. In Fig. 3, first through-hole conductor 18A is provided so as to fill first through hole 17Ba, but it is sufficient that first through-hole conductor 18A is provided at least on the inner wall surface of first through hole 17Ba.

[0029] A second through-hole conductor 18B extending in the thickness direction is preferably formed inside the second through-hole 17Bb. In FIG. 3, the second through-hole conductor 18B is provided so as to penetrate the capacitor layer 10 and the sealing layer 20 in the thickness direction. As shown in FIG. 3, the second through-hole conductor 18B is preferably electrically insulated from the anode plate 11 by the inner wall of the second through-hole 17Bb. In FIG. 3, the second through-hole conductor 18B is provided so as to fill the third through-hole 17C, which has a smaller diameter than the second through-hole 17Bb. However, it is sufficient that the second through-hole conductor 18B is provided at least on the inner wall surface of the third through-hole 17C. The diameter of the third through-hole 17C may be the same as, larger than, or smaller than the diameter of the first through-hole 17Ba.

[0030] The anode plate 11 is made of a valve metal that exhibits so-called valve action. Examples of the valve metal include simple metals such as aluminum, tantalum, niobium, titanium, and zirconium, as well as alloys containing at least one of these metals. Among these, aluminum or an aluminum alloy is preferred.

[0031] The anode plate 11 is preferably in the form of a flat plate, and more preferably in the form of a foil. The anode plate 11 may have a porous layer 12 on at least one of its main surfaces, or may have a porous layer 12 on both of its main surfaces. The porous layer 12 is preferably an etching layer formed on the surface of the anode plate 11.

[0032] The thickness of the anode plate 11 before etching is preferably 60 μm or more and 200 μm or less. The thickness of the unetched core portion after etching 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 the combined thickness of the porous layers 12 on both sides of the core portion is preferably 10 μm or more and 180 μm or less.

[0033] The pore size of the porous layer 12 is preferably 10 nm or more and 600 nm or less. The pore size of the porous layer 12 refers to the median diameter D50 measured with a mercury porosimeter. The pore size of the porous layer 12 can be controlled, for example, by adjusting various etching conditions.

[0034] The dielectric layer 13 is porous, reflecting the surface state of the porous layer 12, and has a finely uneven surface shape. The dielectric layer 13 is preferably made of an oxide film of the valve metal. For example, when an aluminum foil is used as the anode plate 11, a dielectric layer made of an oxide film can be formed by anodizing the surface of the aluminum foil in an aqueous solution containing ammonium adipate or the like (also called chemical conversion treatment).

[0035] The thickness of the dielectric layer 13 is designed according to the required withstand voltage and capacitance, but is preferably 10 nm or more and 100 nm or less.

[0036] The insulating layers 14, such as the first insulating layer 14A and the second insulating layer 14B, are preferably made of resin. Examples of resins that can be used to form the insulating layers include insulating resins such as polyphenylsulfone resin, polyethersulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinylether copolymer, etc.), polyimide resin, polyamideimide resin, epoxy resin, and derivatives or precursors thereof. The first insulating layer 14A and the second insulating layer 14B may be made of the same resin or different resins.

[0037] The insulating layer 14 may be made of the same resin as the sealing layer 20. Unlike the sealing layer 20, if the insulating layer 14 contains an inorganic filler, it may adversely affect the active portion of the solid electrolytic capacitor, and therefore the insulating layer 14 is preferably made of a resin alone.

[0038] The insulating layer 14 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 application, or inkjet printing.

[0039] The thickness of the insulating layer 14 from the surface of the porous layer 12 is preferably 20 μm or less. The thickness of the insulating layer 14 from the surface of the porous layer 12 may be 0 μm, but is preferably 2 μm or more.

[0040] Cathode layer 15 includes a solid electrolyte layer 15A provided on the surface of dielectric layer 13. Cathode layer 15 preferably further includes a conductor layer 15B provided on the surface of solid electrolyte layer 15A.

[0041] Examples of materials constituting the solid electrolyte layer 15A include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene), also known as PEDOT, is particularly preferred. The conductive polymer may also contain a dopant such as polystyrene sulfonate (PSS). The solid electrolyte layer 15A preferably includes an inner layer that fills the pores (recesses) of the dielectric layer 13 and an outer layer that covers the dielectric layer 13.

[0042] The thickness of the solid electrolyte layer 15A from the surface of the porous layer 12 is preferably 2 μm or more and 20 μm or less.

[0043] The solid electrolyte layer 15A is formed, for example, by a method of forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 13 using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion liquid of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric layer 13 and drying it.

[0044] The solid electrolyte layer 15A can be formed in a predetermined region by applying the above-mentioned treatment liquid or dispersion onto the dielectric layer 13 by a method such as sponge transfer, screen printing, dispenser application, or inkjet printing.

[0045] The conductor layer 15B includes at least one of a conductive resin layer and a metal layer. The conductor layer 15B may be only a conductive resin layer or only a metal layer. It is preferable that the conductor layer 15B covers the entire surface of the solid electrolyte layer 15A.

[0046] The conductive resin layer may be, for example, a conductive adhesive layer containing at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler.

[0047] Examples of the metal layer include a metal plating film and a metal foil. The metal layer is preferably made of at least one metal selected from the group consisting of nickel, copper, silver, and alloys containing these metals as the main component. The term "main component" refers to the elemental component with the largest weight ratio.

[0048] Conductor layer 15B includes, for example, a carbon layer provided on the surface of solid electrolyte layer 15A and a copper layer provided on the surface of the carbon layer.

[0049] The carbon layer is provided to electrically and mechanically connect the solid electrolyte layer 15A and the copper layer. The carbon layer can be formed in a predetermined area by applying a carbon paste to the solid electrolyte layer 15A by sponge transfer, screen printing, dispenser application, inkjet printing, or other methods. Note that the carbon layer is preferably laminated with the copper layer in the next step while it is still viscous before drying. The thickness of the carbon layer is preferably 2 μm or more and 20 μm or less.

[0050] The copper layer can be formed by printing a copper paste onto the carbon layer by sponge transfer, screen printing, spray coating, dispenser coating, inkjet printing, etc. The thickness of the copper layer is preferably 2 μm or more and 20 μm or less.

[0051] The number of cathode portions 16, such as first cathode portion 16A and second cathode portion 16B, is not particularly limited as long as it is two or more. The cathode portions 16 may be arranged linearly or in a planar manner. Furthermore, the cathode portions 16 may be arranged regularly or irregularly. The size, planar shape, etc. of the cathode portions 16 as viewed in the thickness direction may be the same, or some or all of them may be different. Two or more types of cathode portions 16 having different areas as viewed in the thickness direction may be included.

[0052] A cathode portion 16 having a non-rectangular planar shape as viewed in the thickness direction may be included. In this specification, "rectangle" means a square or a rectangle. Therefore, for example, a cathode portion 16 having a planar shape other than a rectangle, such as a quadrangle, a triangle, a pentagon, or a hexagon, a shape including a curved portion, a circle, an ellipse, or the like may be included. In this case, two or more types of cathode portions 16 having different planar shapes may be included. Furthermore, in addition to a cathode portion 16 having a non-rectangular planar shape, a cathode portion 16 having a rectangular planar shape may or may not be included.

[0053] Of the two or more cathode portions 16, all of the cathode portions 16 may be surrounded by the first insulating layer 14A, or there may be a cathode portion 16 that is not surrounded by the first insulating layer 14A. In the cathode portion 16 surrounded by the first insulating layer 14A, the entire cathode portion 16 may be surrounded by the first insulating layer 14A, or only a part of the cathode portion 16 may be surrounded by the first insulating layer 14A.

[0054] The first through portion 17A is preferably formed in a slit shape. The width of the first through portion 17A 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 first through portion 17A is preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less.

[0055] At least a portion of the first penetrating portion 17A may be arranged so as not to overlap the entire solid electrolytic capacitor 1. In this case, at least one cathode portion 16 may be arranged on an extension of the first penetrating portion 17A.

[0056] First penetration portion 17A may have a taper that narrows in the thickness direction. When first penetration portion 17A penetrates capacitor layer 10 in the thickness direction, it is preferable that the taper of first penetration portion 17A does not reach anode plate 11.

[0057] The second through portion 17B is preferably a through hole such as a first through hole 17Ba or a second through hole 17Bb. The cross-sectional shape of the second through portion 17B as viewed in the thickness direction is not particularly limited, and examples include a polygon such as a square, a circle, and an ellipse. The hole diameter refers to the diameter when the cross-sectional shape is circular, and refers to the maximum length passing through the center of the cross section when the cross-sectional shape is other than circular. The second through portion 17B may have a taper in which the hole diameter decreases in the thickness direction.

[0058] Through-hole conductors 18, such as first through-hole conductor 18A and second through-hole conductor 18B, are provided to penetrate capacitor layer 10 in the thickness direction. It is sufficient that through-hole conductor 18 is 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. Because of ease of processing, metallization can be performed by, for example, electroless copper plating or electrolytic copper plating. Metallization of through-hole conductor 18 is not limited to metallizing only the inner wall surface of the through-hole; the through-hole may also be filled with a metal or a composite material of metal and resin.

[0059] The through-hole conductors 18 are classified into A. for the anode of the capacitor, and B. for the cathode of the capacitor, ground, and C / O lines. A. The through-hole conductors 18 for the anode of the capacitor are electrically connected to the anode plate 11 of the capacitor layer 10, B. The through-hole conductors 18 for the cathode of the capacitor and ground are electrically connected to the cathode layer 15 of the capacitor layer 10, and the through-hole conductors for the C / O lines are electrically connected to neither the anode plate 11 nor the cathode layer 15 of the capacitor layer 10.

[0060] A. The through-hole conductors 18 for the anodes of the capacitors may or may not have an insulating material filled between the through holes that penetrate the capacitor layer 10 and the through-hole conductors 18. In the latter case, the anode plate 11 and the through-hole conductors 18 are directly connected. B. The through-hole conductors 18 for the cathodes and ground of the capacitors and the through-hole conductors 18 for the C1 / O lines have an insulating material filled between the through holes that penetrate the capacitor layer 10 and the through-hole conductors 18.

[0061] For example, the first through-hole conductor 18A can be used as the through-hole conductor 18 for the anode of the A. capacitor, and the second through-hole conductor 18B can be used as the through-hole conductor 18 for the cathode of the B. capacitor and ground.

[0062] 1, 2, and 3, when the solid electrolytic capacitor 1 includes the sealing layer 20, the sealing layer 20 is provided so as to cover the insulating layer 14 and the cathode layer 15. The sealing layer 20 may be provided so as to cover the capacitor layer 10 from both main surface sides, or may be provided so as to cover the capacitor layer 10 from either one of the main surface sides.

[0063] When the solid electrolytic capacitor 1 includes a sealing layer 20, the first through portion 17A may be filled with the sealing layer 20. When the anode plate 11 is divided between the first cathode portion 16A and the second cathode portion 16B by the first through portion 17A penetrating the anode plate 11 in the thickness direction as shown in Fig. 2, the first through portion 17A between the anode plate 11 of the first cathode portion 16A and the anode plate 11 of the second cathode portion 16B may be filled with the sealing layer 20. The sealing layer 20 reliably divides the anode plate 11 of the first cathode portion 16A from the anode plate 11 of the second cathode portion 16B.

[0064] 3, when second through-hole conductor 18B is formed inside second through hole 17Bb, sealing layer 20 may be filled between second through-hole conductor 18B and anode plate 11. Sealing layer 20 reliably insulates second through-hole conductor 18B from anode plate 11 at the inner wall of second through hole 17Bb.

[0065] The sealing layer 20 is preferably made of a resin. Examples of the resin constituting the sealing layer 20 include epoxy resin and phenol resin. Furthermore, the sealing layer 20 preferably contains a filler. Examples of the filler contained in the sealing layer 20 include inorganic fillers such as silica particles, alumina particles, and metal particles.

[0066] Sealing layer 20 may be composed of only one layer or two or more layers. When sealing layer 20 is composed of two or more layers, the materials constituting each sealing layer may be the same or different.

[0067] Between the capacitor layer 10 and the sealing layer 20, for example, a stress relaxation layer, a moisture-proof film, or other layer may be provided.

[0068] For example, when the solid electrolytic capacitor 1 includes a stress relaxation layer, the stress relaxation layer may be filled in the first penetration portion 17A. When the anode plate 11 is divided between the first cathode portion 16A and the second cathode portion 16B by the first penetration portion 17A penetrating the anode plate 11 in the thickness direction as shown in Fig. 2, the stress relaxation layer may be filled in the first penetration portion 17A between the anode plate 11 of the first cathode portion 16A and the anode plate 11 of the second cathode portion 16B.

[0069] The stress relaxation layer is preferably made of an insulating resin. Examples of insulating resins that make up the stress relaxation layer include epoxy resin, phenolic resin, and silicone resin. Furthermore, the stress relaxation layer preferably contains a filler. Examples of fillers contained in the stress relaxation layer include inorganic fillers such as silica particles, alumina particles, and metal particles. The insulating resin that makes up the stress relaxation layer is preferably different from the resin that makes up the sealing layer 20.

[0070] Because sealing layer 20 is required to have properties such as adhesion to the external electrodes as an exterior body, it is difficult to simply match the linear expansion coefficient with that of capacitor layer 10 or to 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 functions of capacitor layer 10 and sealing layer 20.

[0071] The stress relaxation layer preferably has lower moisture permeability than the sealing layer 20. In this case, in addition to adjusting the stress, it is possible to reduce the penetration of moisture into the capacitor layer 10. The moisture permeability of the stress relaxation layer can be adjusted by the type of insulating resin that constitutes the stress relaxation layer, the amount of filler contained in the stress relaxation layer, etc.

[0072] FIG. 7 is a cross-sectional view schematically showing a first through-hole conductor and its periphery in another example of the solid electrolytic capacitor of the present invention.

[0073] 7, first through-hole conductors 18A are provided so as to penetrate capacitor layer 10 in the thickness direction. Specifically, first through-hole conductors 18A are provided on at least the inner wall surfaces of first through holes 17Ba that penetrate capacitor layer 10 in the thickness direction. In the example shown in FIG. 7, sealing layer 20 includes a first sealing layer 20A provided on the surface of capacitor layer 10 and a second sealing layer 20B provided on the surface of first sealing layer 20A.

[0074] As shown in FIG. 7, the first through-hole conductor 18A is preferably electrically connected to the end surface of the anode plate 11.

[0075] 7, it is preferable that porous layer 12 is exposed on the end surface of anode plate 11 that is electrically connected to first through-hole conductor 18A. In this case, the contact area between first through-hole conductor 18A and porous layer 12 is increased, which improves adhesion and makes it less likely for problems such as peeling of first through-hole conductor 18A to occur.

[0076] 7, an insulating material is filled in the porous layer 12 exposed on the edge surface of the anode plate 11 electrically connected to the first through-hole conductor 18A, thereby providing a second insulating layer 14B around the first through-hole conductor 18A. Filling the porous layer 12 around the first through-hole conductor 18A with an insulating material ensures insulation between the anode plate 11 and the cathode layer 15, thereby preventing short circuits. Furthermore, suppressing dissolution of the edge surface of the anode plate 11 during chemical treatment to form the conductive portion 30, etc., described below, prevents the chemical from penetrating into the capacitor layer 10, thereby improving the reliability of the capacitor.

[0077] The second insulating layer 14B is filled inside the porous layer 12 and is provided on the surface of the porous layer 12 above the filled portion. As such, the thickness of the second insulating layer 14B is preferably greater than the thickness of the porous layer 12.

[0078] The first through-hole conductor 18A is formed, for example, as follows. First, a first through hole 17Ba is formed by drilling, laser processing, or the like in the area where the first through-hole conductor 18A is to be formed. Then, the inner wall surface of the first through hole 17Ba is metallized with a low-resistance metal such as copper, gold, or silver, thereby forming the first through-hole conductor 18A. When forming the first through-hole conductor 18A, for example, metallizing the inner wall surface of the first through hole 17Ba with electroless copper plating, electrolytic copper plating, or the like makes processing easier. Note that the method of forming the first through-hole conductor 18A may be a method of filling the first through hole 17Ba with a metal, a composite material of metal and resin, or the like, in addition to a method of metallizing the inner wall surface of the first through hole 17Ba.

[0079] 7, it is preferable that an anode connection layer 19 is provided between the first through-hole conductor 18A and the end face of the anode plate 11, and that the first through-hole conductor 18A is electrically connected to the end face of the anode plate 11 via the anode connection layer 19. By providing the anode connection layer 19 between the first through-hole conductor 18A and the end face of the anode plate 11, the anode connection layer 19 functions as a barrier layer against the anode plate 11 and the porous layer 12. As a result, dissolution of the anode plate 11 that occurs during chemical treatment to form the conductive portion 30, etc., described below, can be suppressed, and therefore the chemical solution can be prevented from penetrating into the capacitor layer 10, improving the reliability of the capacitor.

[0080] When the anode connection layer 19 is provided between the first through-hole conductor 18A and the end surface of the anode plate 11, the anode connection layer 19 includes, for example, a first anode connection layer 19A primarily made of zinc and a second anode connection layer 19B primarily made of nickel or copper, in that order from the anode plate 11, as shown in FIG. 7 . For example, the first anode connection layer 19A is formed on the end surface of the anode plate 11 by displacement deposition of zinc using a zincate treatment, and then the second anode connection layer 19B is formed on the first anode connection layer 19A by electroless nickel plating or electroless copper plating. Note that the first anode connection layer 19A may disappear, in which case the anode connection layer 19 may include only the second anode connection layer 19B.

[0081] In particular, it is preferable that the anode connecting layer 19 includes a layer mainly made of nickel. By using nickel for the anode connecting layer 19, damage to metals such as aluminum that constitute the anode plate 11 can be reduced, thereby improving the barrier properties.

[0082] When the anode connecting layer 19 is provided between the first through-hole conductor 18A and the end face of the anode plate 11, the dimension of the anode connecting layer 19 in the thickness direction is preferably larger than the dimension of the anode plate 11 in the thickness direction. In this case, the end faces of the anode plate 11 and the porous layer 12 are entirely covered with the anode connecting layer 19, which further suppresses the dissolution of the anode plate 11 described above.

[0083] The dimension of the anode connecting layer 19 in the thickness direction is preferably greater than 100% and less than 200% of the dimension of the anode plate 11 in the thickness direction. The dimension of the anode connecting layer 19 in the thickness direction may be the same as or smaller than the dimension of the anode plate 11 in the thickness direction.

[0084] The anode connecting layer 19 does not have to be provided between the first through-hole conductor 18A and the end surface of the anode plate 11. In this case, the first through-hole conductor 18A is directly connected to the end surface of the anode plate 11.

[0085] 1, first through-hole conductor 18A is preferably electrically connected to the end face of anode plate 11 around the entire periphery of first through hole 17Ba. In this case, the contact area between first through-hole conductor 18A and anode plate 11 is increased, thereby reducing the connection resistance with first through-hole conductor 18A and lowering the equivalent series resistance (ESR) of the capacitor. Furthermore, the increased adhesion between first through-hole conductor 18A and anode plate 11 reduces the likelihood of problems such as peeling at the connection surface due to thermal stress.

[0086] It is preferable that first through hole 17Ba be filled with a material containing resin. That is, as shown in Fig. 7, it is preferable that first resin filling portion 21A is provided inside first through hole 17Ba. By filling first through hole 17Ba with a resin material to eliminate voids, it is possible to prevent delamination of first through-hole conductor 18A formed on the inner wall surface of first through hole 17Ba.

[0087] The material filled in first through hole 17Ba preferably has a higher thermal expansion coefficient than the material (e.g., copper) constituting first through-hole conductor 18A. In this case, the material filled in first through hole 17Ba expands in a high-temperature environment, pressing first through-hole conductor 18A from the inside to the outside of first through hole 17Ba, further preventing delamination of first through-hole conductor 18A.

[0088] The thermal expansion coefficient of the material filled in the first through hole 17Ba may be the same as the thermal expansion coefficient of the material constituting the first through-hole conductor 18A, or may be smaller than the thermal expansion coefficient of the material constituting the first through-hole conductor 18A.

[0089] First through hole 17Ba does not have to be filled with a material containing resin. In this case, first through-hole conductor 18A is preferably provided not only on the inner wall surface of first through hole 17Ba but also throughout the interior of first through hole 17Ba.

[0090] As shown in Fig. 7, the solid electrolytic capacitor 1A preferably further includes a conductive portion 30 electrically connected to the first through-hole conductor 18A. In the example shown in Fig. 7, the conductive portion 30 is provided on the surface of the first through-hole conductor 18A. The conductive portion 30 can function as a connection terminal of the solid electrolytic capacitor 1A (capacitor layer 10).

[0091] Examples of materials that can be used to form the conductive portions 30 include low-resistance metals such as silver, gold, copper, etc. In this case, the conductive portions 30 are formed by, for example, plating the surfaces of the first through-hole conductors 18A.

[0092] In order to improve the adhesion between the conductive portion 30 and other components, in this case, the adhesion between the conductive portion 30 and the first through-hole conductor 18A, a mixed material of at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler and resin may be used as the constituent material of the conductive portion 30.

[0093] FIG. 8 is a cross-sectional view schematically showing the second through-hole conductor and its periphery in the solid electrolytic capacitor shown in FIG.

[0094] In solid electrolytic capacitor 1A shown in Fig. 8, second through-hole conductor 18B is provided so as to penetrate capacitor layer 10 in the thickness direction. Specifically, second through-hole conductor 18B is formed on at least the inner wall surface of third through hole 17C that penetrates capacitor layer 10 in the thickness direction. In the example shown in Fig. 8, sealing layer 20 includes first sealing layer 20A provided on the surface of capacitor layer 10 and second sealing layer 20B provided on the surface of first sealing layer 20A.

[0095] As shown in Fig. 8, the second through-hole conductor 18B is preferably electrically connected to the cathode layer 15. Here, in the example shown in Fig. 8, a conductive portion 40 is provided on the surface of the second through-hole conductor 18B and can function as a connection terminal of the solid electrolytic capacitor 1A (capacitor layer 10). Also, in the example shown in Fig. 8, a via conductor 42 is provided so as to penetrate the sealing layer 20 in the thickness direction and connect to the conductive portion 40 and the cathode layer 15. Therefore, in the example shown in Fig. 8, the second through-hole conductor 18B is electrically connected to the cathode layer 15 via the conductive portion 40 and the via conductor 42. In this case, the solid electrolytic capacitor 1A can be made smaller.

[0096] The second through-hole conductor 18B is formed, for example, as follows. First, a second through hole 17Bb is formed by drilling, laser processing, or the like in the area where the second through-hole conductor 18B is to be formed. Next, an insulating layer is formed by filling the second through hole 17Bb with a constituent material of the second sealing layer 20B (e.g., a resin material). The formed insulating layer is then formed by drilling, laser processing, or the like. At this time, the diameter of the third through hole 17C is made smaller than the diameter of the second through hole 17Bb, so that the constituent material of the second sealing layer 20B is present between the second through hole 17Bb and the third through hole 17C. Then, the inner wall surface of the third through hole 17C is metallized with a low-resistance metal such as copper, gold, or silver, to form the second through-hole conductor 18B. When forming second through-hole conductor 18B, for example, metallizing the inner wall surface of third through hole 17C by electroless copper plating, electrolytic copper plating, etc. As a method for forming second through-hole conductor 18B, in addition to the method of metallizing the inner wall surface of third through hole 17C, a method of filling third through hole 17C with a metal, a composite material of metal and resin, etc. may also be used.

[0097] Examples of materials that can be used to form the conductive portions 40 include low-resistance metals such as silver, gold, copper, etc. In this case, the conductive portions 40 are formed by plating the surfaces of the second through-hole conductors 18B, for example.

[0098] In order to improve the adhesion between the conductive portion 40 and other components, in this case, the adhesion between the conductive portion 40 and the second through-hole conductor 18B, a mixed material of at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler and resin may be used as the constituent material of the conductive portion 40.

[0099] Examples of materials that can be used to form the via conductors 42 include materials similar to those that can be used to form the conductive portions 40 .

[0100] The via conductor 42 is formed, for example, by plating the inner wall surface of a through hole that is provided to penetrate the sealing layer 20 in the thickness direction, or by filling it with a conductive paste and then performing a heat treatment.

[0101] Third through hole 17C is preferably filled with a material containing resin. That is, as shown in Fig. 8, second resin filling portion 21B is preferably provided in third through hole 17C. Filling third through hole 17C with a resin material to eliminate voids can prevent delamination of second through-hole conductor 18B formed on the inner wall surface of third through hole 17C.

[0102] The material filled in third through hole 17C preferably has a higher thermal expansion coefficient than the material (e.g., copper) constituting second through-hole conductor 18B. In this case, the material filled in third through hole 17C expands in a high-temperature environment, pressing second through-hole conductor 18B from the inside to the outside of third through hole 17C, further preventing delamination of second through-hole conductor 18B.

[0103] The thermal expansion coefficient of the material filled in the third through hole 17C may be the same as the thermal expansion coefficient of the material constituting the second through-hole conductor 18B, or may be smaller than the thermal expansion coefficient of the material constituting the second through-hole conductor 18B.

[0104] Third through hole 17C does not have to be filled with a material containing resin. In this case, second through-hole conductor 18B is preferably provided not only on the inner wall surface of third through hole 17C but also throughout the interior of third through hole 17C.

[0105] 8, when sealing layer 20 includes first sealing layer 20A and second sealing layer 20B, second sealing layer 20B preferably extends between second through-hole conductor 18B and anode plate 11. The presence of second sealing layer 20B between second through-hole conductor 18B and anode plate 11 ensures insulation between second through-hole conductor 18B and anode plate 11.

[0106] When second sealing layer 20B extends between second through-hole conductor 18B and anode plate 11, porous layer 12 is preferably exposed at the end face of anode plate 11 that contacts second sealing layer 20B, as shown in Fig. 8. In this case, the contact area between second sealing layer 20B and porous layer 12 is increased, improving adhesion and reducing the likelihood of problems such as peeling.

[0107] 8, an insulating material is filled into porous layer 12 exposed on the end surface of anode plate 11 in contact with second sealing layer 20B, thereby providing second insulating layer 14B around second through-hole conductor 18B. By filling porous layer 12 around a certain portion of second through-hole conductor 18B with an insulating material, insulation between second through-hole conductor 18B and anode plate 11 can be ensured, thereby preventing short circuits.

[0108] The second insulating layer 14B is filled inside the porous layer 12 and is provided on the surface of the porous layer 12 above the filled portion. As such, the thickness of the second insulating layer 14B is preferably greater than the thickness of the porous layer 12.

[0109] When second sealing layer 20B extends between second through-hole conductor 18B and anode plate 11, it is preferable that the insulating material constituting second sealing layer 20B penetrates into the hollow portion of porous layer 12. This improves the mechanical strength of porous layer 12. It also prevents delamination due to voids in porous layer 12.

[0110] The insulating material constituting second sealing layer 20B preferably has a higher thermal expansion coefficient than the material (e.g., copper) constituting second through-hole conductor 18B. In this case, the insulating material constituting second sealing layer 20B expands in a high-temperature environment, thereby pressing down porous layer 12 and second through-hole conductor 18B, further reducing the occurrence of delamination.

[0111] The thermal expansion coefficient of the insulating material constituting the second sealing layer 20B may be the same as the thermal expansion coefficient of the material constituting the second through-hole conductor 18B, or may be smaller than the thermal expansion coefficient of the material constituting the second through-hole conductor 18B.

[0112] [Solid electrolytic capacitor manufacturing method] The method for manufacturing a solid electrolytic capacitor of the present invention includes the steps of forming an insulating layer on an anode plate, forming a cathode layer, and forming a first penetrating portion.

[0113] An example of a method for manufacturing the solid electrolytic capacitor 1 shown in FIG. 1 will now be described step by step with reference to the drawings.

[0114] FIG. 9 is a perspective view schematically showing an example of a step of forming an insulating layer on an anode plate.

[0115] First, an anode plate 11 made of a valve metal is prepared. Although not shown in Fig. 9, a porous layer 12 (see Fig. 5, etc.) is provided on at least one main surface of the anode plate 11, and a dielectric layer 13 (see Fig. 5, etc.) is provided on the surface of the porous layer 12.

[0116] For example, the dielectric layer 13 is formed on the surface of the porous layer 12 by anodizing the anode plate 11 having the porous layer 12 on at least one of its main surfaces.

[0117] Alternatively, a chemically formed foil may be prepared as the anode plate 11 having the dielectric layer 13 provided on the surface of the porous layer 12 .

[0118] Next, the insulating layer 14 is formed so as to fill the inside of the porous layer 12 and on the surface of the porous layer 12 above the filled portion.

[0119] The step of forming the insulating layer 14 includes a step of forming a first insulating layer 14A surrounding at least one element region 16′ when viewed in the thickness direction so as to divide the anode plate 11 into two or more element regions 16′. Fig. 9 shows a pair of adjacent first and second element regions 16a and 16b among the element regions 16′, and the first insulating layer 14A is formed so as to surround the first and second element regions 16a and 16b.

[0120] The step of forming the insulating layer 14 may further include a step of forming a second insulating layer 14B in the element region 16' surrounded by the first insulating layer 14A. In this case, the second insulating layer 14B only needs to be formed in at least one element region 16'. In FIG. 9, the second insulating layer 14B is formed in the first element region 16a and the second element region 16b.

[0121] The insulating layers 14, such as the first insulating layer 14A and the second insulating layer 14B, are preferably formed by applying, transferring, or printing a solution or dispersion containing an insulating resin (hereinafter referred to as insulating ink) onto the surface of the porous layer 12. By allowing the insulating ink to soak into the porous layer 12, the insulating layer 14 can be formed so as to fill the inside of the porous layer 12 and on the surface of the porous layer 12 above the filled portion.

[0122] In the process of forming the insulating layer 14, it is preferable that the surface tension of the insulating ink is 20 mN / m or more and 50 mN / m or less, the static contact angle between the insulating ink and the porous layer is 50° or more and 90° or less, and the viscosity of the insulating ink is 1.5 Pa·s or more and 25 Pa·s or less.

[0123] The penetration of insulating ink into the anode plate 11 provided with the porous layer 12 is generally explained by the following Lucas-Washburn equation: L=(r·γ·t·cosθ / 2η) 1 / 2 (In the formula, L represents the penetration depth, r represents the capillary radius, γ represents the surface tension, η represents the viscosity, θ represents the contact angle, and t represents the penetration time.)

[0124] Assuming that the capillary radius r, which is due to the pore diameter of the anode plate 11 provided with the porous layer 12, and the penetration time t, which is due to the application method, are constant, the penetration depth L of the insulating ink into the anode plate 11 provided with the porous layer 12, can be considered to be dominated by the surface tension γ of the insulating ink, the contact angle θ between the insulating ink and the porous layer, and the viscosity η of the insulating ink.

[0125] By setting the surface tension of the insulating ink to 20 mN / m or more and 50 mN / m or less, the static contact angle between the insulating ink and the porous layer to 50° or more and 90° or less, and the viscosity of the insulating ink to 1.5 Pa·s or more and 25 Pa·s or less, it is possible to control the penetration of the insulating ink into the porous layer 12. This makes it difficult for the insulating ink to penetrate into unnecessary areas of the porous layer 12, allowing the insulating ink to penetrate into necessary areas of the porous layer 12. Specifically, the insulating ink can be penetrated perpendicular to the thickness direction of the area where the insulating ink is applied. In other words, the insulating layer 14 can be formed perpendicular to the thickness direction of the area where the insulating ink is applied. As a result, in the obtained solid electrolytic capacitor, variation in the capacitance expected from the projected area defined by the insulating ink can be reduced.

[0126] The surface tension of the insulating ink and the static contact angle between the insulating ink and the porous layer refer to values ​​measured at 25°C using an interfacial tensiometer (for example, the fully automatic interfacial tensiometer PD-W manufactured by Kyowa Interface Science Co., Ltd.).

[0127] The viscosity of the insulating ink is a value measured using a rotational viscometer at 25° C. Specifically, it is a value measured using an E-type viscometer at a speed of 10 rpm.

[0128] FIG. 10 is a perspective view schematically illustrating an example of a step of forming a cathode layer.

[0129] A cathode layer 15 is formed on the surface of the dielectric layer 13. The cathode layer 15 is formed in each element region 16'. This divides the cathode layer 15 into two or more cathode portions 16 (see FIG. 4, etc.).

[0130] As the cathode layer 15, a solid electrolyte layer 15A (see FIG. 5, etc.) is formed on the surface of the dielectric layer 13 in the element region 16′. As the cathode layer 15, it is preferable that a conductor layer 15B (see FIG. 5, etc.) is further formed on the surface of the solid electrolyte layer 15A.

[0131] As a result of the above, a capacitor layer 10 is produced, which includes an anode plate 11, a porous layer 12 provided on at least one main surface of the anode plate 11, a dielectric layer 13 provided on the surface of the porous layer 12, an insulating layer 14 filled inside the porous layer 12 and provided on the surface of the porous layer 12 above the filled portion, and a cathode layer 15 provided on the surface of the dielectric layer 13, as shown in Figures 4, 5, and 6.

[0132] FIG. 11 is a perspective view schematically illustrating an example of a step of forming a first penetrating portion.

[0133] The first penetrating portion 17A is formed so as to penetrate both the porous layer 12 and the first insulating layer 14A in the thickness direction. The first penetrating portion 17A may also penetrate the anode plate 11 in the thickness direction. In other words, the first penetrating portion 17A may also penetrate the capacitor layer 10 in the thickness direction.

[0134] Examples of methods for forming the first penetrating portion 17A include laser processing and dicing.

[0135] The anode plate 11 may be divided between at least one pair of adjacent first and second cathode portions 16A and 16B of the cathode portion 16. Specifically, the anode plate 11 may be physically divided between at least one pair of adjacent first and second cathode portions 16A and 16B of the cathode portion 16, or the anode plate 11 may be electrically divided. For example, the anode plate 11 may be divided between the first and second cathode portions 16A and 16B by a first penetration portion 17A penetrating the anode plate 11 in the thickness direction.

[0136] When the step of forming the insulating layer further includes the step of forming a second insulating layer, the method for manufacturing a solid electrolytic capacitor of the present invention may further include the step of forming a second penetrating portion.

[0137] 9, when a second insulating layer 14B is formed as the insulating layer 14, a second penetrating portion 17B (see FIG. 4, etc.) may be formed to penetrate both the porous layer 12 and the second insulating layer 14B in the thickness direction. The second penetrating portion 17B may also penetrate the anode plate 11 in the thickness direction. In other words, the second penetrating portion 17B may also penetrate the capacitor layer 10 in the thickness direction.

[0138] Examples of methods for forming the second through portion 17B include laser processing and drilling.

[0139] The step of forming the second through portion may include the steps of forming a first through hole and forming a second through hole having a larger diameter than the first through hole.

[0140] FIG. 12 is a perspective view schematically illustrating an example of a step of forming a second through hole, among the steps of forming the second penetrating portion.

[0141] In FIG. 12, a second through hole 17Bb is formed as the second through portion 17B.

[0142] The method for manufacturing a solid electrolytic capacitor of the present invention may further include a step of forming a sealing layer so as to cover the insulating layer and the cathode layer.

[0143] FIG. 13 is a perspective view schematically illustrating an example of a step of forming a sealing layer.

[0144] For example, the sealing layer 20 is formed by applying an insulating material by press working so as to cover the capacitor layer 10 from both or either of the main surface sides.

[0145] 13 , the sealing layer 20 may be filled in the first through portion 17A. When the anode plate 11 is divided between the first cathode portion 16A and the second cathode portion 16B by the first through portion 17A penetrating the anode plate 11 in the thickness direction, the sealing layer 20 may be filled in the first through portion 17A between the anode plate 11 of the first cathode portion 16A and the anode plate 11 of the second cathode portion 16B. The sealing layer 20 reliably divides the anode plate 11 of the first cathode portion 16A from the anode plate 11 of the second cathode portion 16B.

[0146] When the second through-holes 17Bb are formed, the second through-holes 17Bb may be filled with a sealing layer 20 as shown in FIG.

[0147] FIG. 14 is a perspective view schematically illustrating an example of a step of forming a first through hole, among the steps of forming a second through portion.

[0148] 14, a first through hole 17Ba having a smaller diameter than second through hole 17Bb is formed as second through portion 17B. In FIG. 14, a third through hole 17C having a smaller diameter than second through hole 17Bb is also formed. The diameter of third through hole 17C may be the same as, larger than, or smaller than the diameter of first through hole 17Ba.

[0149] The method for manufacturing a solid electrolytic capacitor of the present invention preferably further comprises the step of forming a through-hole conductor extending in the thickness direction inside the second penetrating portion.

[0150] FIG. 15 is a perspective view schematically showing an example of a step of forming a through-hole conductor.

[0151] 15, it is preferable that through-hole conductors 18 extending in the thickness direction are formed inside second penetrating portions 17B. In this case, it is preferable that through-hole conductors 18 are formed so as to penetrate capacitor layer 10 and sealing layer 20 in the thickness direction.

[0152] A first through-hole conductor 18A extending in the thickness direction is formed inside first through hole 17Ba. First through-hole conductor 18A is preferably formed so as to penetrate capacitor layer 10 and sealing layer 20 in the thickness direction. First through-hole conductor 18A is preferably electrically connected to anode plate 11 on the inner wall of first through hole 17Ba. In FIG. 15, first through-hole conductor 18A is formed so as to fill first through hole 17Ba, but it is sufficient that first through-hole conductor 18A is formed on at least the inner wall surface of first through hole 17Ba.

[0153] A second through-hole conductor 18B extending in the thickness direction is formed inside second through hole 17Bb. Second through-hole conductor 18B is preferably formed so as to penetrate capacitor layer 10 and sealing layer 20 in the thickness direction. Second through-hole conductor 18B is preferably electrically insulated from anode plate 11 by the inner wall of second through hole 17Bb. In FIG. 15, second through-hole conductor 18B is formed so as to fill third through hole 17C, but second through-hole conductor 18B only needs to be formed on at least the inner wall surface of third through hole 17C.

[0154] 15, when second through-hole conductor 18B is formed inside second through hole 17Bb, sealing layer 20 may be filled between second through-hole conductor 18B and anode plate 11. Sealing layer 20 reliably insulates second through-hole conductor 18B from anode plate 11 at the inner wall of second through hole 17Bb.

[0155] By the above method, the solid electrolytic capacitor 1 shown in FIG. 1 can be manufactured.

[0156] As described above, when manufacturing the solid electrolytic capacitor of the present invention, methods for forming the first penetrating portion include laser processing, dicing, and the like. Among these, laser processing allows the cathode portion to be formed into any desired shape. This makes it possible to arrange two or more capacitor layers with different cathode portion areas in one solid electrolytic capacitor, to arrange the first penetrating portion so that it does not extend over the entire solid electrolytic capacitor, and to arrange capacitor layers whose cathode portion has a non-rectangular planar shape.

[0157] [Composite electronic components] The solid electrolytic capacitor 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 solid electrolytic capacitor of the present invention, external electrodes provided on the outside of the solid electrolytic capacitor (preferably on the outside of the sealing layer of the solid electrolytic capacitor) and connected to the anode plate and cathode layer of the solid electrolytic capacitor, and an electronic component connected to the external electrodes.

[0158] In a composite electronic component, the electronic component connected to the external electrode may be a passive element or an active element. Both the passive element and the active element may be connected to the external electrode, or either the passive element or the active element may be connected to the external electrode. Also, a composite of a passive element and an active element may be connected to the external electrode.

[0159] Examples of passive elements include inductors, etc. Examples of active elements include memories, GPUs (Graphical Processing Units), CPUs (Central Processing Units), MPUs (Micro Processing Units), and PMICs (Power Management ICs).

[0160] The solid electrolytic capacitor of the present invention has a sheet-like shape as a whole. Therefore, in a composite electronic component, the solid electrolytic capacitor can be treated like a mounting substrate, and electronic components can be mounted on the solid electrolytic capacitor. Furthermore, by making the electronic components mounted on the solid electrolytic capacitor sheet-like, it is possible to connect the solid electrolytic capacitor and the electronic components in the thickness direction via through-hole conductors that penetrate each electronic component in the thickness direction. As a result, active elements and passive elements can be configured like a single module.

[0161] For example, a switching regulator can be formed by electrically connecting the solid electrolytic capacitor of the present invention between a voltage regulator including a semiconductor active element and a load to which the converted DC voltage is supplied.

[0162] In a composite electronic component, a circuit layer may be formed on either side of a capacitor matrix sheet on which a plurality of solid electrolytic capacitors of the present invention are laid out, and the circuit layer may be connected to a passive element or an active element.

[0163] Alternatively, the solid electrolytic capacitor of the present invention may be placed in a cavity provided in a substrate, embedded in resin, and then a circuit layer may be formed on the resin. Another electronic component (a passive element or an active element) may be mounted in another cavity of the same substrate.

[0164] Alternatively, the solid electrolytic capacitor of the present invention may be mounted on a smooth carrier such as a wafer or glass, an outer layer made of resin may be formed, a circuit layer may be formed, and then the capacitor may be connected to a passive element or an active element. [Example]

[0165] EXAMPLES Hereinafter, examples will be given that more specifically disclose the solid electrolytic capacitor and the method for manufacturing the solid electrolytic capacitor of the present invention, but the present invention is not limited to these examples.

[0166] [Fabrication of capacitor elements] An etched aluminum foil was prepared as the anode plate.

[0167] An insulating layer was formed on the anode plate so as to partition the anode plate into rectangular element regions using insulating ink with the physical properties shown in Table 1. Depending on the viscosity of the insulating ink, a pattern surrounding the element region was formed by transferring or coating for low-viscosity insulating ink, or by printing for high-viscosity insulating ink, and then the insulating ink was cured and dried to form the insulating layer.

[0168] A solid electrolyte layer was formed in the element region. A dispersion of the conductive polymer poly(3,4-ethylenedioxythiophene) was used as the treatment liquid containing the solid electrolyte. After the solid electrolyte layer was formed, a carbon layer and a copper layer were formed.

[0169] Capacitor elements were fabricated through the above process. Ten levels of capacitor elements were fabricated under each condition.

[0170] [Capacitor element evaluation] (Appearance after application) After forming the insulating layer, when forming the cathode layer by dipping or printing, the insulating layer must have a certain height. Therefore, we checked whether the insulating layer remained on the surface of the porous layer. By observing the cross section of the capacitor element, if no insulating layer remained on the surface of the porous layer, it was judged as × (bad), if the height of the insulating layer from the surface of the porous layer was more than 0 μm but less than 5 μm, it was judged as △ (passable), and if the height of the insulating layer from the surface of the porous layer was 5 μm or more, it was judged as ○ (good). The results are shown in Table 1.

[0171] (porous layer penetration) To confirm whether the insulating ink had soaked into the required areas of the porous layer, the cross section of the capacitor element was observed to confirm whether an insulating layer had been formed perpendicular to the thickness direction in the area where the insulating ink had been applied. Specifically, the insulating layer was confirmed from a mapping image of the C element, and the solid electrolyte layer was confirmed from a mapping image of the S element. If the insulating layer was not formed perpendicularly, it was judged as × (bad), and if the insulating layer was formed perpendicularly, it was judged as ○ (good). The results are shown in Table 1.

[0172] (Capacitance design difference) As an indicator of whether the penetration of the insulating ink was controlled, we checked the degree of variation in the capacitance expected from the projected area defined by the insulating ink. If the variation in capacitance is large, it can be determined that there is also a large variation in the formation of the insulating layer. The results are shown in Table 1.

[0173] [Table 1]

[0174] In Samples 1 to 3, in which the static contact angle between the insulating ink and the porous layer was less than 50°, no insulating layer remained on the surface of the porous layer.

[0175] In Sample 10, in which the viscosity of the insulating ink was greater than 25 Pa·s, an insulating layer was not formed perpendicular to the thickness direction in the area where the insulating ink was applied.

[0176] In sample 14, in which the surface tension of the insulating ink was greater than 50 mN / m and the static contact angle between the insulating ink and the porous layer was greater than 90°, no insulating layer remained on the surface of the porous layer, and no insulating layer was formed perpendicular to the thickness direction in the area where the insulating ink was applied.

[0177] On the other hand, in samples 4 to 9 and 11 to 13, in which the surface tension of the insulating ink was 20 mN / m or more and 50 mN / m or less, the static contact angle between the insulating ink and the porous layer was 50° or more and 90° or less, and the viscosity of the insulating ink was 1.5 Pa·s or more and 25 Pa·s or less, an insulating layer remained on the surface of the porous layer, and an insulating layer was formed perpendicular to the thickness direction of the area where the insulating ink was applied. [Explanation of symbols]

[0178] 1. 1A solid electrolytic capacitor 10 Capacitor Layer 11 Anode plate 12 Porous layer 13 Dielectric layer 14 Insulating layer 14A First insulating layer 14B Second insulating layer 15 Cathode layer 15A solid electrolyte layer 15B Conductor layer 16 Cathode 16A 1st cathode section 16B 2nd cathode section 16' element area 16a First element region 16b Second element region 17A 1st penetration part 17B 2nd penetration part 17Ba 1st through hole 17Bb 2nd through hole 17C 3rd through hole 18 through-hole conductor 18A First through-hole conductor 18B Second through-hole conductor 19 Anode connection layer 20 Sealing layer 20A 1st sealing layer 20B 2nd sealing layer 21A 1st resin filling section 21B 2nd resin filling section 30, 40 Conductive part 42 via conductor

Claims

1. a step of forming an insulating layer on an anode plate made of a valve metal, the anode plate having a porous layer on at least one main surface thereof and a dielectric layer on the surface of the porous layer, so as to fill the inside of the porous layer and on the surface of the porous layer above the filled portion; forming a cathode layer including a solid electrolyte layer provided on a surface of the dielectric layer; Equipped with the insulating layer is formed using an insulating ink having a viscosity of 1.5 Pa·s or more and 25 Pa·s or less; the cathode layer is formed in an element region of the anode plate so as to be divided into at least one cathode portion; The method for manufacturing a solid electrolytic capacitor further comprises the step of forming a through portion so as to penetrate both the porous layer and the insulating layer in the thickness direction.

2. A method for manufacturing a solid electrolytic capacitor as described in claim 1, wherein the surface tension of the insulating ink is 20 mN / m or more and 50 mN / m or less.

3. A method for manufacturing a solid electrolytic capacitor as described in claim 1, wherein the static contact angle between the insulating ink and the porous layer is 50° or more and 90° or less.

4. 4. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the step of forming the insulating layer includes the steps of: forming a first insulating layer that surrounds the element region when viewed from the thickness direction; and forming a second insulating layer within the element region surrounded by the first insulating layer.

5. A method for manufacturing a solid electrolytic capacitor as described in claim 4, wherein the process of forming the penetration portion includes a process of forming a first penetration portion so as to penetrate both the porous layer and the first insulating layer in the thickness direction, and a process of forming a second penetration portion so as to penetrate both the porous layer and the second insulating layer in the thickness direction.

6. 6. The method for manufacturing a solid electrolytic capacitor according to claim 5, further comprising the step of forming a through-hole conductor extending in the thickness direction inside the second penetrating portion.

7. 6. The method for manufacturing a solid electrolytic capacitor according to claim 5, wherein the step of forming the second through portion includes the steps of forming a first through hole and forming a second through hole having a larger diameter than the first through hole.

8. forming a first through-hole conductor extending in the thickness direction inside the first through hole; 8. The method for manufacturing a solid electrolytic capacitor according to claim 7, wherein the first through-hole conductor is electrically connected to the anode plate on an inner wall of the first through hole.

9. forming a second through-hole conductor extending in the thickness direction inside the second through hole; 8. The method for manufacturing a solid electrolytic capacitor according to claim 7, wherein the second through-hole conductor is electrically insulated from the anode plate by an inner wall of the second through hole.

10. forming a sealing layer to cover the insulating layer and the cathode layer; The method for manufacturing a solid electrolytic capacitor according to claim 9 , wherein the sealing layer is filled between the second through-hole conductor and the anode plate.

11. 4. The method for manufacturing a solid electrolytic capacitor according to claim 1, further comprising the step of forming a sealing layer so as to cover the insulating layer and the cathode layer.

12. 4. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the anode plate is divided between at least one pair of adjacent first and second cathode portions among the cathode portions.

13. The method for manufacturing a solid electrolytic capacitor according to claim 12 , wherein the through portion penetrates the anode plate in the thickness direction between the first cathode portion and the second cathode portion, thereby dividing the anode plate.

14. forming a sealing layer to cover the insulating layer and the cathode layer; The method for manufacturing a solid electrolytic capacitor according to claim 13 , wherein the sealing layer fills the through portion between the anode plate of the first cathode portion and the anode plate of the second cathode portion.

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