Method for manufacturing solid electrolytic capacitors, method for manufacturing capacitor arrays, solid electrolytic capacitors and capacitor arrays

Abstract

To provide a solid electrolytic capacitor and a capacitor array, which are suppressed in increase of equivalent series resistance during long-term use in a high-temperature environment and also high in capacitance, and methods of manufacturing the same.SOLUTION: In a method of manufacturing a solid electrolytic capacitor, a process for forming a cathode layer 20 on a surface of a dielectric layer 13 on an anode plate 10 includes the steps of: forming a first conductive polymer layer 21A containing a first conductive polymer, by using a liquid containing the first conductive polymer; forming a second conductive polymer layer 21B in which a second conductive polymer and an insulating material are mixed, by using a liquid in which the second conductive polymer having a larger particle size than the first conductive polymer is dispersed and a liquid containing an insulating material that suppresses deterioration due to heat and oxidization of a conductive polymer contained in a solid electrolyte layer 21; and forming a third conductive polymer layer 21C containing a third conductive polymer and a binder and covering the second conductive polymer layer.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a solid electrolytic capacitor, a method for manufacturing a capacitor array, 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 an electrolytic capacitor including an anode body, a dielectric layer formed on the anode body, and a solid electrolyte layer formed on the dielectric layer, the solid electrolyte layer including a conductive polymer, and the conductive polymer including self-doped poly(3,4-ethylenedioxythiophene) compounds.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the electrolytic capacitor described in Patent Document 1, it is possible to suppress the increase in equivalent series resistance (ESR) in high-temperature environments by using self-doped poly(3,4-ethylenedioxythiophene) compounds as conductive polymers. This is thought to be because the skeleton of the above conductive polymer has higher heat resistance compared to polyaniline compounds, and the conductive polymer is less likely to deteriorate in high-temperature environments. By using the above conductive polymer, deterioration of the solid electrolyte layer is suppressed even in high-temperature environments, and the occurrence of cracks or fractures in the solid electrolyte layer is suppressed. As a result, the increase in resistance in the solid electrolyte layer is suppressed, and high electrical conductivity can be maintained, thus suppressing the increase in ESR in high-temperature environments.

[0006] Thus, Patent Document 1 proposes a solid electrolytic capacitor that ensures high capacitance while maintaining low ESR even in high-temperature environments, thus providing high heat resistance. However, when considering long-term operation in high-temperature environments such as 105°C or 125°C, there is a risk that the ESR may increase.

[0007] The present invention aims to provide a method for manufacturing a solid electrolytic capacitor that suppresses the increase in equivalent series resistance during long-term use in high-temperature environments and has high capacitance. Furthermore, the present invention aims to provide a method for manufacturing a capacitor array comprising the above-mentioned solid electrolytic capacitor as a capacitor element, the above-mentioned solid electrolytic capacitor, and the above-mentioned capacitor array. [Means for solving the problem]

[0008] The present invention provides a method for manufacturing a solid electrolytic capacitor, comprising the steps of: preparing an anode plate having a core, a porous layer provided on at least one main surface of the core, and a dielectric layer provided on the surface of the porous layer; and forming a cathode layer on the surface of the dielectric layer. The step of forming the cathode layer includes forming a solid electrolyte layer containing a conductive polymer on the surface of the dielectric layer. The step of forming the solid electrolyte layer includes forming a first conductive polymer layer inside the pores of the dielectric layer; forming a second conductive polymer layer covering the first conductive polymer layer inside the pores of the dielectric layer; and forming a third conductive polymer layer on the surface of the anode plate, covering at least the second conductive polymer layer. In the step of forming the first conductive polymer layer, a liquid containing the first conductive polymer is used to form the layer containing the first conductive polymer. In the step of forming the second conductive polymer layer described above, a liquid in which the second conductive polymer, which has a larger particle size than the first conductive polymer, is dispersed, and a liquid containing an insulating material that suppresses the deterioration of the conductive polymer contained in the solid electrolyte layer due to heat and oxidation, are used to form a layer in which the second conductive polymer and the insulating material are mixed.

[0009] The present invention provides a method for manufacturing a capacitor array, comprising the steps of: preparing an anode plate having a core, a porous layer provided on at least one main surface of the core, and a dielectric layer provided on the surface of the porous layer; forming a mask layer on the surface of the porous layer to divide the anode plate into a plurality of element regions; forming a cathode layer on the surface of the dielectric layer within the element regions divided by the mask layer; separating the anode plate on which the cathode layer is formed into a plurality of capacitor elements by dividing the element regions; and forming a sealing layer to cover the plurality of capacitor elements. The step of forming the cathode layer includes forming a solid electrolyte layer containing a conductive polymer on the surface of the dielectric layer. The step of forming the solid electrolyte layer includes forming a first conductive polymer layer inside the pores of the dielectric layer; forming a second conductive polymer layer inside the pores of the dielectric layer that covers the first conductive polymer layer; and forming a third conductive polymer layer on the surface of the anode plate that covers at least the second conductive polymer layer. In the step of forming the first conductive polymer layer, a layer containing the first conductive polymer is formed using a liquid containing the first conductive polymer. In the step of forming the second conductive polymer layer, a layer containing a mixture of the second conductive polymer and the insulating material is 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 containing an insulating material that suppresses thermal and oxidative degradation of the conductive polymer contained in the solid electrolyte layer.

[0010] The solid electrolytic capacitor of the present invention comprises a core portion, an anode plate having 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 is provided on the surface of the dielectric layer and includes a solid electrolyte layer containing a conductive polymer. The solid electrolyte layer includes a first conductive polymer layer provided inside the pores of the dielectric layer, a second conductive polymer layer provided inside the pores of the dielectric layer and covering the first conductive polymer layer, and a third conductive polymer layer provided on the surface of the anode plate and covering at least the second conductive polymer layer. The first conductive polymer layer is a layer containing a self-doped first conductive polymer. The second conductive polymer layer is a layer in which a non-self-doped second conductive polymer and an insulating material that suppresses thermal and oxidative degradation of the conductive polymer contained in the solid electrolyte layer are mixed.

[0011] The capacitor array of the present invention comprises a plurality of capacitor elements and a sealing layer provided so as to cover the plurality of capacitor elements. Each of the plurality of capacitor elements is a solid electrolytic capacitor of the present invention. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a method for manufacturing a solid electrolytic capacitor that suppresses the increase in equivalent series resistance during long-term use in high-temperature environments and has high capacitance. Furthermore, according to the present invention, it is possible to provide a method for manufacturing a capacitor array comprising the above-mentioned solid electrolytic capacitor as a capacitor element, the above-mentioned solid electrolytic capacitor, and the above-mentioned capacitor array. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of the solid electrolytic capacitor of the present invention. [Figure 2] Figure 2 is a perspective view of the solid electrolytic capacitor shown in Figure 1. [Figure 3]FIG. 3 is an enlarged cross-sectional view of the portion surrounded by the dashed line in the solid electrolytic capacitor shown in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view schematically showing another example of the solid electrolytic capacitor of the present invention. [Figure 5] FIG. 5 is a perspective view of the state where the third conductive polymer layer, the first conductor layer, and the second conductor layer are removed from the solid electrolytic capacitor shown in FIG. 4. [Figure 6] FIG. 6 is a cross-sectional view schematically showing still another example of the solid electrolytic capacitor of the present invention. [Figure 7] FIG. 7 is a perspective view schematically showing an example of the process of preparing an anode plate. [Figure 8] FIG. 8 is an enlarged cross-sectional view of the portion surrounded by the dashed line in the anode plate shown in FIG. 7. [Figure 9] FIG. 9 is a cross-sectional view schematically showing an example of the process of forming the first conductive polymer layer. [Figure 10] FIG. 10 is a cross-sectional view schematically showing an example of the process of forming the second conductive polymer layer. [Figure 11] FIG. 11 is a perspective view schematically showing an example of the process of forming the third conductive polymer layer. [Figure 12] FIG. 12 is an enlarged cross-sectional view of the portion surrounded by the dashed line in the anode plate shown in FIG. 11. [Figure 13] FIG. 13 is a perspective view schematically showing an example of the process of forming the first conductor layer. [Figure 14] FIG. 14 is an enlarged cross-sectional view of the portion surrounded by the dashed line in the anode plate shown in FIG. 13. [Figure 15] FIG. 15 is a perspective view schematically showing an example of the process of forming the second conductor layer. [Figure 16] FIG. 16 is an enlarged cross-sectional view of the portion surrounded by the dashed line in the anode plate shown in FIG. 15. [Figure 17] FIG. 17 is a cross-sectional view schematically showing an example of the capacitor array of the present invention. [Figure 18]Figure 18 is a perspective view of the capacitor array shown in Figure 17. [Figure 19] Figure 19 is an enlarged cross-sectional view of the portion surrounded by the dashed line in the capacitor array shown in Figure 18. [Figure 20] Figure 20 is a perspective view schematically showing an example of the process of preparing the anode plate. [Figure 21] Figure 21 is a perspective view schematically showing an example of the process of forming the solid electrolyte layer. [Figure 22] Figure 22 is an enlarged cross-sectional view of the portion surrounded by the dashed line in the anode plate shown in Figure 21. [Figure 23] Figure 23 is a perspective view schematically showing an example of the process of forming the first conductor layer. [Figure 24] Figure 24 is a perspective view schematically showing an example of the process of forming the second conductor layer. [Figure 25] Figure 25 is a perspective view schematically showing an example of the process of dividing the anode plate on which the cathode layer is formed. [Figure 26] Figure 26 is a perspective view schematically showing an example of the process of forming the second through hole. [Figure 27] Figure 27 is a perspective view schematically showing an example of the process of forming the sealing layer. [Figure 28] Figure 28 is a perspective view schematically showing an example of the process of forming the first through hole. [Figure 29] Figure 29 is a perspective view schematically showing an example of the process of forming the through hole conductor. [Figure 30] Figure 30 is a perspective view schematically showing an example of the process of forming the via conductor. [Figure 31] Figure 31 is a cross-sectional view schematically showing a part of the solid electrolyte layer constituting the solid electrolytic capacitor of Example 1. [Figure 32] Figure 32 is a cross-sectional view schematically showing a part of the solid electrolyte layer constituting the solid electrolytic capacitor of Comparative Example 1. [Figure 33] Figure 33 is a cross-sectional view schematically showing a part of the solid electrolyte layer constituting the solid electrolytic capacitor of Comparative Example 2. [Figure 34] Figure 34 is a graph showing the ESR of the solid electrolytic capacitors in Example 1 and Comparative Example 1. [Figure 35] Figure 35 is a graph showing the ESR change rate of solid electrolytic capacitors in Example 1 and Comparative Example 2. [Figure 36] Figure 36 is a graph showing the capacitance of the solid electrolytic capacitors in Example 1 and Comparative Example 2. [Modes for carrying out the invention]

[0014] The following describes the method for manufacturing a solid electrolytic capacitor, the method for manufacturing a capacitor array, the solid electrolytic capacitor, and the capacitor array of the present invention. However, the present invention is not limited to the following configurations and can be modified and applied as appropriate without altering the essence of the invention. Furthermore, a combination of two or more of the individual desirable configurations of the present invention described below also constitutes the present invention.

[0015] The drawings shown below are schematic representations, and their dimensions, aspect ratios, and scales may differ from those of the actual product.

[0016] [Solid electrolytic capacitors] Figure 1 is a schematic cross-sectional view showing an example of the solid electrolytic capacitor of the present invention. Figure 2 is a perspective view of the solid electrolytic capacitor shown in Figure 1. Note that Figure 1 is a cross-sectional view of the solid electrolytic capacitor shown in Figure 2 along line AA. Figure 3 is an enlarged cross-sectional view of the portion enclosed by the dashed line in the solid electrolytic capacitor shown in Figure 2.

[0017] The solid electrolytic capacitor 1 shown in Figures 1 and 2 comprises an anode plate 10 and a cathode layer 20. As shown in Figures 1 and 2, the solid electrolytic capacitor 1 may further include a mask layer 30 provided in the region surrounding the cathode layer 20.

[0018] The anode plate 10 has a core portion 11, a porous layer 12 provided on at least one main surface of the core portion 11, and a dielectric layer 13 (see Figure 3) provided on the surface of the porous layer 12. In Figure 1, the porous layer 12 of the anode plate 10 is shown alone, but in reality, as will be described later, a part of the solid electrolyte layer 21 that constitutes the cathode layer 20 is provided inside the pores (recesses) of the dielectric layer 13. The same applies to Figures 4, 6 and 17.

[0019] The anode plate 10 is made of a valve metal that exhibits a so-called valve action. Examples of valve metals include elemental metals such as aluminum, tantalum, niobium, titanium, and zirconium, or alloys containing at least one of these metals. Among these, aluminum or aluminum alloys are preferred.

[0020] The anode plate 10 is preferably flat, and more preferably foil-shaped. In the anode plate 10, a porous layer 12 may be provided on at least one main surface of the core portion 11, or both main surfaces of the core portion 11 may be provided with the porous layer 12. The porous layer 12 is preferably an etched layer formed on the surface of the anode plate 10.

[0021] The thickness of the anode plate 10 before etching is preferably 60 μm or more and 200 μm or less. The thickness of the unetched core portion 11 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 11 is preferably 10 μm or more and 180 μm or less.

[0022] The pore size of the porous layer 12 is preferably between 10 nm and 600 nm. The pore size of the porous layer 12 refers to the median diameter D50 measured by a mercury porosimeter. The pore size of the porous layer 12 can be controlled, for example, by adjusting various conditions during 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 Figure 3). Preferably, the dielectric layer 13 is made of an oxide film of the valve metal. For example, when aluminum foil is used as the anode plate 10, the dielectric layer 13 made of an oxide film can be formed by performing an anodic oxidation treatment (also called chemical conversion 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 to match the required voltage 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 a mask layer 30 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 mask layer 30 (hereinafter also referred to as the element region). The cathode layer 20 may also be provided so as to extend to the surface of the mask layer 30.

[0026] The cathode layer 20 includes a solid electrolyte layer 21 provided on the surface of the dielectric layer 13. Preferably, the cathode layer 20 further includes a conductive layer 22 provided on the surface of the solid electrolyte layer 21. In Figure 1, the solid electrolyte layer 21 is shown completely separated from the porous layer 12 of the anode plate 10, but in reality, as shown in Figure 3, the first conductive polymer layer 21A and the second conductive polymer layer 21B constituting the solid electrolyte layer 21 are provided inside the pores (recesses) of the dielectric layer 13, and the third conductive polymer layer 21C constituting the solid electrolyte layer 21 is provided on the surface of the anode plate 10.

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

[0028] Examples of materials constituting the solid electrolyte layer 21 include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene) called PEDOT is particularly preferred. Furthermore, the conductive polymer may contain dopants 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 microscope image of the cross-section in the thickness direction of the anode plate 10, as shown in Figure 3. The method for measuring the thickness of each layer constituting the solid electrolyte layer 21, which will be described later, is similar.

[0031] As shown in Figure 3, 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.

[0032] 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 it may cover only a portion of the pores of the dielectric layer 13.

[0033] The first conductive polymer layer 21A is a layer containing a self-doped first conductive polymer. The self-doped first conductive polymer may be one type or two or more types. The first conductive polymer layer 21A may be one layer or two or more layers.

[0034] Self-doped conductive polymers refer to conductive polymers that have anionic groups directly or indirectly bonded to their backbone (e.g., poly(3,4-ethylenedioxythiophene) backbone) via covalent bonds. These polymers are called self-doped because the anionic groups inherent in the conductive polymer itself function as dopants for the conductive polymer. Anionic groups include, for example, acidic groups (acid type) or their conjugated anionic groups (salt type).

[0035] Examples of anionic groups include sulfonic acid groups, carboxyl groups, phosphate groups, phosphonic acid groups, or salts thereof (salts with inorganic bases, salts with organic bases). There may be only one anionic group or two or more. Sulfonic acid groups or salts thereof are preferred as anionic groups, and combinations of sulfonic acid groups or salts thereof with anionic groups other than sulfonic acid groups or salts thereof are also acceptable.

[0036] The first conductive polymer layer 21A may contain conductive polymers other than the first conductive polymer (for example, a second non-self-doped conductive polymer as described later), but the ratio of the first conductive polymer to the total conductive polymers contained in the first conductive polymer layer 21A is, for example, 90% by mass or more, and may be 100% by mass.

[0037] The first conductive polymer may optionally contain a dopant.

[0038] The first conductive polymer layer 21A is formed, for example, by 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. Specifically, the first conductive polymer layer 21A can be formed in a predetermined area by applying the above liquid to the surface of the anode plate 10 by immersion (dip method), sponge transfer, screen printing, dispenser, inkjet printing, etc.

[0039] 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 it may cover a part of the first conductive polymer layer 21A. The second conductive polymer layer 21B may also fill the pores (recesses) of the dielectric layer 13.

[0040] The second conductive polymer layer 21B is a layer in which a non-self-doped second conductive polymer and an insulating material that suppresses thermal and oxidative degradation of the conductive polymer contained in the solid electrolyte layer 21 are mixed. The non-self-doped second conductive polymer may be of one type or two or more types. Similarly, the insulating material may be of one type or two or more types. The second conductive polymer layer 21B may be one layer or two or more layers.

[0041] In the solid electrolytic capacitor 1, the capacitance can be increased because the conductive polymer penetrates deep into the pores of the dielectric layer 13 by covering most of the interior of the pores of the dielectric layer 13 with a first conductive polymer layer 21A containing a self-doped first conductive polymer. On the other hand, the non-self-doped second conductive polymer has lower penetration than the self-doped first conductive polymer, but has high heat resistance. However, in this state, the heat resistance is insufficient, and the ESR increases when used in a high-temperature environment. To suppress this increase in ESR, an insulating material is used to suppress the deterioration of the conductive polymer contained in the solid electrolyte layer 21 due to heat and oxidation. However, the addition of an insulating material to the solid electrolyte layer 21 creates a trade-off with the initial ESR. Therefore, by forming the second conductive polymer layer 21B in a state where the second conductive polymer and the insulating material are mixed, it is possible to achieve both a reduction in the initial ESR and suppression of the increase in ESR.

[0042] As a result, a solid electrolytic capacitor 1 can be obtained in which the increase in ESR during long-term use in high-temperature environments is suppressed and the capacitance is high.

[0043] A non-self-doped conductive polymer refers to a conductive polymer that does not have anionic groups (specifically, sulfonic acid groups, carboxyl groups, phosphate groups, phosphonic acid groups, and salts thereof) directly or indirectly bonded to the conductive polymer backbone by covalent bonds.

[0044] The second conductive polymer may optionally contain a dopant.

[0045] The insulating material is not particularly limited as long as it has the function of suppressing the degradation of the conductive polymer due to heat and oxidation. Examples of such insulating materials include materials that have the function of supplying hydrogen radicals (H·) to radicals (R·) generated in the molecular chain of the conductive polymer as a starting point due to heat, and to peroxy radicals (ROO·) generated when the above radicals (R·) react with oxygen, such as phenolic materials or phosphorus-based materials. Alternatively, the insulating material may be a material that reacts with oxygen at an activation energy lower than the activation energy in the reaction between the conductive polymer and oxygen (for example, a hydrocarbon material having an unsaturated group in the molecule), activated carbon, or a material with excellent gas adsorption properties such as zeolite.

[0046] From the viewpoint of lowering the ESR, it is preferable that the insulating material is not unevenly distributed within the second conductive polymer layer 21B, and it is more preferable that the insulating material is uniformly dispersed within the second conductive polymer layer 21B. For example, it is preferable that at least one of the conductive polymers contained in the solid electrolyte layer 21 is present in the region within 5 μm where the insulating material is present, and it is more preferable that at least one of the conductive polymers contained in the solid electrolyte layer 21 is present in the region within 2 μm where the insulating material is present.

[0047] 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 greater than the thickness of the first conductive polymer layer 21A, or may be less than the thickness of the first conductive polymer layer 21A.

[0048] The second conductive polymer layer 21B is formed, for example, by simultaneously applying 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, to the surface of the anode plate 10 on which the first conductive polymer layer 21A is formed, and then drying them. Specifically, the second conductive polymer layer 21B can be formed in a predetermined area by simultaneously applying these liquids to the surface of the anode plate 10 on which the first conductive polymer layer 21A is formed by immersion (dip method), sponge transfer, screen printing, dispenser, inkjet printing, etc.

[0049] 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.

[0050] The third conductive polymer layer 21C is a layer containing the third conductive polymer. Preferably, the third conductive polymer layer 21C further contains a binder. The third conductive polymer layer 21C may be one layer or two or more layers.

[0051] The third conductive polymer may be self-doped or unself-doped. The third conductive polymer may be one type or two or more types. The third conductive polymer may contain a dopant as needed.

[0052] 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.

[0053] The third conductive polymer layer 21C is formed, for example, by 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 then drying it. Specifically, the third conductive polymer layer 21C can be formed in a predetermined area by applying the above-mentioned liquid 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, using methods such as dipping, sponge transfer, screen printing, a dispenser, or inkjet printing.

[0054] Alternatively, a third conductive polymer layer 21C may be formed by using a liquid containing a monomer such as 3,4-ethylenedioxythiophene to form a polymerized film of a 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. In this case as well, the third conductive polymer layer 21C can be formed in a predetermined area by applying the above liquid 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 immersion (dip method), sponge transfer, screen printing, dispenser, inkjet printing, etc.

[0055] The conductive layer 22 includes at least one layer from among a conductive resin layer and a metal layer. The conductive layer 22 may consist only of a conductive resin layer or only of a metal layer. The conductive layer 22 may cover the entire solid electrolyte layer 21 or cover only a part of the solid electrolyte layer 21.

[0056] Examples of conductive resin layers include conductive adhesive layers containing at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler.

[0057] Examples of the metal layer include metal plating films and metal foils. Preferably, the metal layer consists of at least one metal selected from the group consisting of nickel, copper, silver, and alloys mainly composed of these metals. "Main component" refers to the element with the largest weight proportion.

[0058] The conductive layer 22 includes, for example, a first conductive layer 22A provided on the surface of the solid electrolyte layer 21 and a second conductive layer 22B provided on the surface of the first conductive layer 22A. Thus, it is preferable that the conductive layer 22 includes multiple types of conductive layers.

[0059] The first conductive 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 silver filler, copper filler, nickel filler, and carbon filler.

[0060] The second conductive 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 silver filler, copper filler, and nickel filler.

[0061] As an example, the conductive layer 22 includes a carbon layer as the first conductive layer 22A and a copper layer as the second conductive layer 22B.

[0062] 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 area on the solid electrolyte layer 21 by applying carbon paste using a dipping method, sponge transfer, screen printing, dispenser, inkjet printing, or the like. It is preferable to laminate the copper layer in the next step while the carbon layer is still viscous before drying. The thickness of the carbon layer is preferably 2 μm or more and 20 μm or less.

[0063] The copper layer can be formed by printing copper paste onto the carbon layer using methods such as dipping, sponge transfer, screen printing, spray coating, dispensing, or inkjet printing. The thickness of the copper layer is preferably 2 μm or more and 20 μm or less.

[0064] The mask layer 30 is provided on the surface of the porous layer 12. The mask layer 30 may also be provided on the surface of the dielectric layer 13 on the porous layer 12. Preferably, the mask layer 30 is provided so as to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0065] The mask layer 30 contains an insulating material.

[0066] The mask layer 30 is preferably made of a resin. Examples of resins that make up the mask layer 30 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 derivatives or precursors thereof.

[0067] Since the inclusion of inorganic fillers in the mask layer 30 may adversely affect the effective portion of the solid electrolytic capacitor 1, it is preferable that the mask layer 30 be made of a resin-only system.

[0068] The mask layer 30 can be formed, for example, by applying a mask material, such as a composition containing an insulating resin, onto the porous layer 12 using methods such as sponge transfer, screen printing, dispensing, or inkjet printing.

[0069] The thickness of the mask layer 30 from the surface of the anode plate 10 is preferably 20 μm or less. The thickness of the mask layer 30 from the surface of the anode plate 10 may be 0 μm, but it is preferably 2 μm or more.

[0070] The thickness of the mask layer 30 can be measured by electron microscope images of the cross-section in the thickness direction of the anode plate 10.

[0071] Figure 4 is a schematic cross-sectional view showing another example of the solid electrolytic capacitor of the present invention. Figure 5 is a perspective view of the solid electrolytic capacitor shown in Figure 4 with the third conductive polymer layer, the first conductive layer, and the second conductive layer removed.

[0072] In the solid electrolytic capacitor 1A shown in Figure 4, a portion of the first conductive polymer layer 21A and / or a portion of the second conductive polymer layer 21B are exposed on the surface of the anode plate 10. As shown in Figure 5, the area of ​​the region on the surface of the anode plate 10 where the first conductive polymer layer 21A and the second conductive polymer layer 21B are present is larger than the area of ​​the region on the surface of the anode plate 10 where the first conductive polymer layer 21A and the second conductive polymer layer 21B are present. Note that on the surface of the anode plate 10, only a portion of the first conductive polymer layer 21A may be exposed, only a portion of the second conductive polymer layer 21B may be exposed, or both a portion of the first conductive polymer layer 21A and a portion of the second conductive polymer layer 21B may be exposed.

[0073] As shown in Figure 5, it is preferable that the portion of the first conductive polymer layer 21A and / or the second conductive polymer layer 21B exposed on the surface of the anode plate 10 is in contact with the mask layer 30. In particular, it is preferable that a portion of the first conductive polymer layer 21A and / or a portion of the second conductive polymer layer 21B is exposed along the inner edge of the mask layer 30. In this case, a portion of the first conductive polymer layer 21A and / or a portion of the second conductive polymer layer 21B may be exposed along the entire inner edge of the mask layer 30, or they may be exposed along a portion of the inner edge of the mask layer 30.

[0074] In the solid electrolytic capacitor 1A shown in Figure 4, a portion of the third conductive polymer layer 21C further penetrates into the pores of the dielectric layer 13 (see Figure 3). When the third conductive polymer layer 21C covers the pores of the dielectric layer 13 and penetrates into the pores of the dielectric layer 13, the anchoring effect of the third conductive polymer layer 21C makes it easier to suppress the occurrence of delamination between the porous layer 12 and the solid electrolyte layer 21.

[0075] The depth to which the third conductive polymer layer 21C penetrates is not particularly limited; it is sufficient that a portion of the third conductive polymer layer 21C penetrates into the pores of the dielectric layer 13 when observing a cross-section in the thickness direction of the anode plate 10 as shown in Figure 3.

[0076] In the solid electrolytic capacitor 1A shown in Figure 4, if the cathode layer 20 includes a conductive layer 22, the conductive layer 22 may include a conductive resin layer containing a metal filler. For example, if the second conductive layer 22B is a conductive resin layer containing a metal filler, the difference in thermal properties such as the coefficient of linear expansion between the solid electrolyte layer 21 and the conductive layer 22 becomes large, making delamination between the solid electrolyte layer 21 and the conductive layer 22 more likely. Even in such a case, the occurrence of delamination between the solid electrolyte layer 21 and the conductive layer 22 can be suppressed by a portion of the third conductive polymer layer 21C entering the pores of the dielectric layer 13.

[0077] Figure 6 is a schematic cross-sectional view showing yet another example of the solid electrolytic capacitor of the present invention.

[0078] In the solid electrolytic capacitor 1B shown in Figure 6, a sealing layer 40 is provided so as to cover the cathode layer 20. The sealing layer 40 covers not only the cathode layer 20 but also the mask layer 30. The sealing layer 40 may be provided so as to cover both main surfaces of the anode plate 10, or it may be provided so as to cover either one of the main surfaces of the anode plate 10.

[0079] In the example shown in Figure 6, a sealing layer 40 is provided to cover a capacitor element having the same configuration as the solid electrolytic capacitor 1 shown in Figures 1 and 2. However, the capacitor element covered by the sealing layer 40 may be a solid electrolytic capacitor such as the solid electrolytic capacitor 1A shown in Figure 4. Furthermore, two or more types of capacitor elements may be covered by the sealing layer 40.

[0080] The sealing layer 40 contains an insulating material.

[0081] The sealing layer 40 is preferably made of a resin. Examples of resins that make up the sealing layer 40 include epoxy resin and phenolic resin. The sealing layer 40 may also be made of the same resin as the mask layer 30.

[0082] The sealing layer 40 preferably further contains fillers. Examples of fillers included in the sealing layer 40 include inorganic fillers such as silica particles, alumina particles, and metal particles.

[0083] The sealing layer 40 may consist of only one layer or of two or more layers. If the sealing layer 40 consists of two or more layers, the materials constituting each sealing layer may be the same or different.

[0084] A layer such as a stress-relieving layer or a moisture-proof film may be provided between the sealing layer 40 and the cathode layer 20, or between the sealing layer 40 and the mask layer 30.

[0085] The stress relaxation layer is preferably composed of an insulating resin. Examples of insulating resins that constitute the stress relaxation layer include epoxy resin, phenolic resin, and silicone resin. Furthermore, the stress relaxation layer is preferably composed of a filler. Examples of fillers that constitute the stress relaxation layer include inorganic fillers such as silica particles, alumina particles, and metal particles. The insulating resin that constitutes the stress relaxation layer is preferably different from the resin that constitutes the sealing layer 40.

[0086] Since the sealing layer 40 is required to have properties such as adhesion to the external electrodes as an outer casing, it is difficult to simply match its coefficient of thermal expansion with that of a capacitor element such as a solid electrolytic capacitor 1 or to select a resin with an arbitrary modulus of elasticity. In contrast, by providing a stress relaxation layer, it is possible to adjust the thermal stress design without losing the functions of both the capacitor element and the sealing layer 40.

[0087] The stress relaxation layer is preferably less permeable to moisture than the sealing layer 40. In this case, in addition to adjusting the stress, the intrusion of moisture into the capacitor element can be reduced. The permeability of the stress relaxation layer can be adjusted by the type of insulating resin that makes up the stress relaxation layer, the amount of filler contained in the stress relaxation layer, and so on.

[0088] As shown in Figure 6, via conductors 50 may be provided in the sealing layer 40.

[0089] The via conductor 50 is provided so as to extend in the thickness direction from the surface of the sealing layer 40 to the cathode layer 20 (the second conductive layer 22B in the example shown in Figure 6). As a result, the cathode layer 20 is electrically led out to the outside of the sealing layer 40 via the via conductor 50, making it electrically connectable to the outside of the sealing layer 40.

[0090] Examples of materials that make up the via conductor 50 include low-resistance metals such as silver, gold, and copper.

[0091] The via conductor 50 is formed, for example, as follows. First, holes are formed in the sealing layer 40 in the thickness direction, reaching from the surface of the sealing layer 40 to the cathode layer 20 (for example, the second conductive layer 22B) by drilling, laser processing, etc. Then, the via conductor 50 is formed in the holes formed in the sealing layer 40 by plating the inner wall surface or by filling it with conductive paste and then performing heat treatment.

[0092] Although not shown in Figure 6, the solid electrolytic capacitor 1B may be provided with through-hole conductors 60 such as the first through-hole conductor 61 and the second through-hole conductor 62, which will be described later.

[0093] [Manufacturing method for solid electrolytic capacitors] Hereinafter, as an example of a method for manufacturing the solid electrolytic capacitor of the present invention, an example of a method for manufacturing the solid electrolytic capacitor 1 shown in Figures 1 and 2 will be described step by step with reference to the drawings.

[0094] Figure 7 is a schematic perspective view showing an example of the process for preparing an anode plate. Figure 8 is an enlarged cross-sectional view of the portion of the anode plate shown in Figure 7 that is enclosed by a dashed line.

[0095] For example, an anode plate 10 made of valve metal is prepared. The anode plate 10 has a core portion 11 (see Figure 1), a porous layer 12 (see Figures 1 and 8) provided on at least one main surface of the core portion 11, and a dielectric layer 13 (see Figure 8) provided on the surface of the porous layer 12.

[0096] For example, by performing an anodic oxidation treatment on an anode plate 10 having a porous layer 12 provided on at least one main surface of the core portion 11, a dielectric layer 13 can be formed on the surface of the porous layer 12.

[0097] Alternatively, a chemical conversion foil may be prepared as the anode plate 10, in which a dielectric layer 13 is provided on the surface of a porous layer 12.

[0098] As shown in Figure 7, a mask layer 30 may be formed on the surface of the porous layer 12 so as to surround the region on the anode plate 10 where the cathode layer 20 is to be formed. The mask layer 30 may also be formed on the surface of the dielectric layer 13 on the porous layer 12. Preferably, the mask layer 30 is formed to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0099] Next, a cathode layer 20 is formed on the surface of the dielectric layer 13. When a mask layer 30 is formed on the anode plate 10, it is preferable to form the cathode layer 20 on the surface of the dielectric layer 13 within the element region surrounded by the mask layer 30. Alternatively, the cathode layer 20 may be formed so as to extend to the surface of the mask layer 30.

[0100] The step of forming the cathode layer 20 includes the step of forming a solid electrolyte layer 21 containing a conductive polymer on the surface of the dielectric layer 13.

[0101] The process of forming the solid electrolyte layer 21 includes the steps of forming a first conductive polymer layer 21A, forming a second conductive polymer layer 21B, and forming a third conductive polymer layer 21C.

[0102] Figure 9 is a schematic cross-sectional view showing an example of the process for forming the first conductive polymer layer.

[0103] As shown in Figure 9, 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 to cover the entire pores of the dielectric layer 13, or it may be formed to cover only a portion of the pores of the dielectric layer 13.

[0104] 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. Preferably, the first conductive polymer layer 21A is formed using a liquid in which the first conductive polymer is dissolved.

[0105] The first conductive polymer is, for example, a self-doped conductive polymer. The first conductive polymer may optionally contain a dopant.

[0106] 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 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 can be repeated any number of times depending on the required properties, but considering resistance to delamination, cost minimization, etc., it is preferable to repeat it one to three times.

[0107] Figure 10 is a schematic cross-sectional view showing an example of the process for forming the second conductive polymer layer.

[0108] As shown in Figure 10, a second conductive polymer layer 21B is formed inside the pores (recesses) of the dielectric layer 13, covering the first conductive polymer layer 21A. The second conductive polymer layer 21B may be formed to cover the entire first conductive polymer layer 21A, or it may be formed to cover a part of the first conductive polymer layer 21A. The second conductive polymer layer 21B may also be formed to fill the pores (recesses) of the dielectric layer 13.

[0109] 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 in which the second conductive polymer, which has a larger particle size than the first conductive polymer, is dispersed, and a liquid containing an insulating material that suppresses thermal and oxidative degradation of the conductive polymer contained in the solid electrolyte layer 21. Preferably, the second conductive polymer layer 21B is formed using a liquid in which the second conductive polymer is dispersed and a liquid in which the insulating material is dissolved.

[0110] By covering most of the interior of the pores in the dielectric layer 13 with a first conductive polymer layer 21A containing a first conductive polymer with relatively small particle size, the conductive polymer penetrates deep into the pores of the dielectric layer 13, thereby increasing the capacitance. On the other hand, a second conductive polymer with relatively large particle size has lower permeability than the first conductive polymer, but has high heat resistance. However, in this state, the heat resistance is insufficient, and the ESR increases when used in a high-temperature environment. To suppress this increase in ESR, an insulating material is used to suppress the deterioration of the conductive polymer contained in the solid electrolyte layer 21 due to heat and oxidation. However, the addition of an insulating material to the solid electrolyte layer 21 creates a trade-off with the initial ESR. Therefore, by forming a second conductive polymer layer 21B in a state where the second conductive polymer and the insulating material are mixed, it is possible to achieve both a reduction in the initial ESR and suppression of the increase in ESR.

[0111] The particle size of conductive polymers can be measured by dynamic light scattering (DLS).

[0112] The second conductive polymer is, for example, a non-self-doped conductive polymer. The second conductive polymer may optionally contain a dopant.

[0113] The second conductive polymer layer 21B is preferably formed by simultaneously applying a liquid in which the second conductive polymer is dispersed and a liquid containing an insulating material. Specifically, the second conductive polymer layer 21B is formed by simultaneously applying 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, to the surface of the anode plate 10 on which the first conductive polymer layer 21A is formed, and then drying the mixture. The application and drying can be repeated any number of times depending on the required properties, but for example, when forming a cathode layer containing a metal or a sealing layer, it is preferable to repeat the process one to five times from the viewpoint of improving resistance to delamination.

[0114] Furthermore, simultaneously applying the liquid containing the second conductive polymer and the liquid containing the insulating material means applying the other liquid before the first liquid dries, and the method of doing so is not particularly limited.

[0115] In a method of simultaneously applying a liquid containing a dispersed second conductive polymer and a liquid containing an insulating material, even in combinations of materials where the dispersion stability of the second conductive polymer deteriorates due to the influence of the insulating material, drying and fixing can be carried out before the materials aggregate, compared to a method in which the materials are mixed beforehand.

[0116] From the viewpoint of suppressing an increase in ESR, it is preferable that the solid content weight ratio of the insulating material to the second conductive polymer is 1 / 10 or more and 10 / 1 or less.

[0117] Figure 11 is a schematic perspective view showing an example of the process for forming the third conductive polymer layer. Figure 12 is an enlarged cross-sectional view of the portion enclosed by the dashed line in the anode plate shown in Figure 11.

[0118] As shown in Figures 11 and 12, a third conductive polymer layer 21C is formed on the surface of the anode plate 10, covering at least the second conductive polymer layer 21B. The third conductive polymer layer 21C may be formed 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.

[0119] In the step of forming the third conductive polymer layer 21C, a liquid containing the third conductive polymer is used to form the layer containing the third conductive polymer. It is preferable to use a liquid containing a binder in addition to the third conductive polymer.

[0120] The third conductive polymer may be self-doped or unself-doped. The third conductive polymer may optionally contain a dopant.

[0121] The third conductive polymer layer 21C is formed, for example, by 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 then drying it. Alternatively, the third conductive polymer layer 21C may be formed by using a liquid containing a monomer such as 3,4-ethylenedioxythiophene to form 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.

[0122] The step of forming the cathode layer 20 preferably further includes the step of forming a conductive layer 22 on the surface of the solid electrolyte layer 21.

[0123] The step of forming the conductive layer 22 includes, for example, the step of forming a first conductive layer 22A on the surface of the solid electrolyte layer 21, and the step of forming a second conductive layer 22B on the surface of the first conductive layer 22A.

[0124] Figure 13 is a schematic perspective view showing an example of the process for forming the first conductive layer. Figure 14 is an enlarged cross-sectional view of the portion enclosed by the dashed line in the anode plate shown in Figure 13.

[0125] As shown in Figures 13 and 14, a first conductive layer 22A is formed on the surface of the solid electrolyte layer 21. The first conductive layer 22A is, for example, a conductive resin layer containing a conductive filler.

[0126] Figure 15 is a schematic perspective view showing an example of the process for forming the second conductive layer. Figure 16 is an enlarged cross-sectional view of the portion enclosed by the dashed line in the anode plate shown in Figure 15.

[0127] As shown in Figures 15 and 16, a second conductive layer 22B is formed on the surface of the first conductive layer 22A. This forms the conductive layer 22. The second conductive layer 22B is, for example, a conductive resin layer containing a metal filler. Thus, the step of forming the conductive layer 22 may include the step of forming a conductive resin layer containing a metal filler.

[0128] As an example, the conductive layer 22 includes a carbon layer as the first conductive layer 22A and a copper layer as the second conductive layer 22B.

[0129] Through the above process, the solid electrolytic capacitor 1 shown in Figures 1 and 2 can be manufactured.

[0130] [Capacitor Array] Figure 17 is a schematic cross-sectional view showing an example of the capacitor array of the present invention. Figure 18 is a perspective view of the capacitor array shown in Figure 17. Note that Figure 17 is a cross-sectional view of the capacitor array shown in Figure 18 along line BB. Figure 19 is an enlarged cross-sectional view of the portion enclosed by the dashed line in the capacitor array shown in Figure 18.

[0131] The capacitor array 100 shown in Figures 17 and 18 comprises a plurality of capacitor elements 110 and a sealing layer 40 provided to cover the plurality of capacitor elements 110. Via conductors 50 may be provided in the sealing layer 40. Since the sealing layer 40 and via conductors 50 were explained in the solid electrolytic capacitor 1B shown in Figure 6, a detailed explanation is omitted.

[0132] Each of the multiple capacitor elements 110 is a solid electrolytic capacitor of the present invention. Therefore, details of the capacitor elements 110 are omitted. In the examples shown in Figures 17, 18, and 19, the solid electrolytic capacitor 1 shown in Figures 1 and 2 is used as the capacitor element 110, but other solid electrolytic capacitors such as the solid electrolytic capacitor 1A shown in Figure 4 may also be used.

[0133] The capacitor element 110 comprises an anode plate 10 and a cathode layer 20.

[0134] The anode plate 10 has a core portion 11, a porous layer 12 provided on at least one main surface of the core portion 11, and a dielectric layer 13 (see Figure 19) provided on the surface of the porous layer 12.

[0135] The cathode layer 20 includes a solid electrolyte layer 21 provided on the surface of the dielectric layer 13. Preferably, the cathode layer 20 further includes a conductive layer 22 provided on the surface of the solid electrolyte layer 21.

[0136] As shown in Figure 19, 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.

[0137] The conductive layer 22 includes, for example, a first conductive layer 22A provided on the surface of the solid electrolyte layer 21 and a second conductive layer 22B provided on the surface of the first conductive layer 22A.

[0138] The number of capacitor elements 110 is not particularly limited, as long as there are two or more. The capacitor elements 110 may be arranged in a straight line or in a planar manner. Also, the capacitor elements 110 may be arranged regularly or irregularly. The size and planar shape of the capacitor elements 110 as viewed from the thickness direction may be the same, or some or all of them may be different. Two or more types of capacitor elements 110 with different areas as viewed from the thickness direction may be included.

[0139] Capacitor elements 110 whose planar shape, as viewed from the thickness direction, is not rectangular may be included. In this specification, "rectangle" means a square or rectangle. Therefore, for example, capacitor elements 110 whose planar shape is not a rectangle but a polygon such as a quadrilateral, triangle, pentagon, hexagon, or a shape including a curved portion, or a circle or ellipse may be included. In this case, two or more types of capacitor elements 110 with different planar shapes may be included. In addition to capacitor elements 110 whose planar shape is not rectangular, capacitor elements 110 whose planar shape is rectangular may or may not be included.

[0140] In the capacitor array 100, it is preferable that the mask layer 30 divides it into element regions corresponding to multiple capacitor elements 110.

[0141] Among the multiple capacitor elements 110, all capacitor elements 110 may be surrounded by the mask layer 30, or there may be capacitor elements 110 that are not surrounded by the mask layer 30. In the case of capacitor elements 110 that are surrounded by the mask layer 30, the entire capacitor element 110 may be surrounded by the mask layer 30, or only a part of the capacitor element 110 may be surrounded by the mask layer 30.

[0142] As shown in Figures 17 and 18, it is preferable that the anode plate 10 is electrically separated by a slit between at least one pair of adjacent capacitor elements 110. That is, it is preferable that the slit between at least one pair of adjacent capacitor elements 110 penetrates the anode plate 10 in the thickness direction.

[0143] The width of the slit between adjacent capacitor elements 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 capacitor elements 110 is preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less.

[0144] The slits between adjacent capacitor elements 110 may have a taper that decreases in width in the thickness direction. In that case, the taper of the slits between adjacent capacitor elements 110 may or may not reach the anode plate 10.

[0145] As shown in Figures 17 and 18, at least one insulating layer 35 may be provided within at least one element region. In this case, it is preferable that the insulating layer 35 is provided away from the mask layer 30. In the example shown in Figure 18, two insulating layers 35 are provided within each element region.

[0146] The insulating layer 35 is provided on the surface of the porous layer 12. The insulating layer 35 may also be provided on the surface of the dielectric layer 13 on the porous layer 12. Preferably, the insulating layer 35 is provided so as to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0147] The insulating layer 35 contains insulating material.

[0148] The insulating layer 35 is preferably made of a resin. Examples of resins that make up the mask layer 30 include 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 insulating layer 35 may be made of the same resin as the mask layer 30, or it may be made of a different resin.

[0149] The insulating layer 35 may be made of the same resin as the sealing layer 40. However, unlike the sealing layer 40, if the insulating layer 35 contains an inorganic filler, it may adversely affect the effective portion of the capacitor element 110, so it is preferable that the insulating layer 35 be made of a resin-only system.

[0150] The insulating layer 35 can be formed, for example, by applying a masking material, such as a composition containing an insulating resin, onto the porous layer 12 using methods such as sponge transfer, screen printing, dispensing, or inkjet printing.

[0151] The thickness of the insulating layer 35 from the surface of the anode plate 10 is preferably 20 μm or less. The thickness of the insulating layer 35 from the surface of the anode plate 10 may be 0 μm, but it is preferably 2 μm or more.

[0152] The thickness of the insulating layer 35 can be measured by electron microscope images of the cross-section in the thickness direction of the anode plate 10.

[0153] The planar shape of the insulating layer 35 as viewed from the thickness direction is not particularly limited, and examples include polygons such as squares, circles, ellipses, etc. When two or more insulating layers 35 are provided within the element region, the size and planar shape of the insulating layers 35 as viewed from the thickness direction may be the same, or they may be partially or entirely different.

[0154] The position in which the insulating layer 35 is provided within the element region is not particularly limited. If two or more insulating layers 35 are provided within the element region, the positions in which the insulating layers 35 are provided may be the same, or they may be partially or entirely different.

[0155] If an insulating layer 35 is provided within the element region of the capacitor element 110, a through-hole conductor 60 that penetrates the insulating layer 35 in the thickness direction may be provided, as shown in Figures 17 and 18. In the examples shown in Figures 17 and 18, a first through-hole conductor 61 and a second through-hole conductor 62 are provided as the through-hole conductor 60, but only one of them may be provided.

[0156] The first through-hole conductor 61 is provided inside a first through-hole 71 that penetrates the insulating layer 35 in the thickness direction. In the examples shown in Figures 17 and 18, the first through-hole conductor 61 is provided so as to penetrate the capacitor element 110 and the sealing layer 40 in the thickness direction. As shown in Figure 17, it is preferable that the first through-hole conductor 61 is electrically connected to the anode plate 10 at the inner wall of the first through-hole 71. In the examples shown in Figures 17 and 18, the first through-hole conductor 61 is provided so as to fill the first through-hole 71, but it is sufficient that the first through-hole conductor 61 is provided at least on the inner wall surface of the first through-hole 71.

[0157] The second through-hole conductor 62 is provided inside a second through-hole 72 that penetrates the insulating layer 35 in the thickness direction. Preferably, the diameter of the second through-hole 72 is larger than the diameter of the first through-hole 71. In the examples shown in Figures 17 and 18, the second through-hole conductor 62 is provided so as to penetrate the capacitor element 110 and the sealing layer 40 in the thickness direction. As shown in Figure 17, preferably, the second through-hole conductor 62 is electrically insulated from the anode plate 10 by the inner wall of the second through-hole 72. In the examples shown in Figures 17 and 18, the second through-hole conductor 62 is provided to fill a third through-hole 73 which has a smaller diameter than the second through-hole 72, but the second through-hole conductor 62 only needs to be provided on at least the inner wall surface of the third through-hole 73. The diameter of the third through-hole 73 may be the same as the diameter of the first through-hole 71, may be larger than the diameter of the first through-hole 71, or may be smaller than the diameter of the first through-hole 71.

[0158] The cross-sectional shapes of the first through-hole 71, second through-hole 72, and third through-hole 73, as viewed from the thickness direction, are not particularly limited and can include, for example, polygons such as squares, circles, ellipses, etc. Note that the hole diameter refers to the diameter when the cross-sectional shape is circular, and the maximum length passing through the center of the cross-section when the cross-sectional shape is not circular. These through-holes may have a taper in which the hole diameter decreases in the thickness direction.

[0159] The through-hole conductors 60, such as the first through-hole conductor 61 and the second through-hole conductor 62, are provided so as to penetrate the insulating layer 35 in the thickness direction. The through-hole conductors 60 only need to 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. Due to the ease of processing, metallization can be done, for example, by electroless copper plating or electrolytic copper plating. Note that the metallization of the through-hole conductor 60 is not limited to metallizing only the inner wall surface of the through-hole; the through-hole may also be filled with metal or a composite material of metal and resin.

[0160] The through-hole conductors 60 are classified into A. for the anode of the capacitor, B. for the cathode and ground of the capacitor, and B. for the CI / O line. The through-hole conductor 60 for the anode of the capacitor is electrically connected to the anode plate 10 of the capacitor element 110, the through-hole conductor 60 for the cathode and ground of the capacitor is electrically connected to the cathode layer 20 of the capacitor element 110, and the through-hole conductor 60 for the CI / O line is not electrically connected to either the anode plate 10 or the cathode layer 20 of the capacitor element 110.

[0161] A. The through-hole conductor 60 for the anode of the capacitor may or may not have insulating material filled between the through-hole that penetrates the capacitor element 110 and the through-hole conductor 60. In the latter case, the anode plate 10 and the through-hole conductor 60 are directly connected. B. The through-hole conductors 60 for the cathode and ground of the capacitor, and the through-hole conductors 60 for the CI / O lines, have insulating material filled between the through-hole that penetrates the capacitor element 110 and the through-hole conductor 60.

[0162] For example, the first through-hole conductor 61 can be used as a through-hole conductor 60 for the anode of capacitor A, and the second through-hole conductor 62 can be used as a through-hole conductor 60 for the cathode and ground of capacitor B.

[0163] [Manufacturing method for capacitor arrays] 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 Figures 17 and 18 will be described step by step with reference to the drawings.

[0164] Figure 20 is a schematic perspective view showing an example of the process for preparing an anode plate.

[0165] For example, an anode plate 10 made of valve metal is prepared. The anode plate 10 has a core portion 11 (see Figure 17), a porous layer 12 provided on at least one main surface of the core portion 11 (see Figures 17 and 19), and a dielectric layer 13 provided on the surface of the porous layer 12 (see Figure 19).

[0166] For example, by performing an anodic oxidation treatment on an anode plate 10 having a porous layer 12 provided on at least one main surface of the core portion 11, a dielectric layer 13 can be formed on the surface of the porous layer 12.

[0167] Alternatively, a chemical conversion foil may be prepared as the anode plate 10, in which a dielectric layer 13 is provided on the surface of a porous layer 12.

[0168] As shown in Figure 20, a mask layer 30 is formed on the surface of the porous layer 12 in order to divide the anode plate 10 into multiple element regions. The mask layer 30 may also be formed on the surface of the dielectric layer 13 on the porous layer 12. Preferably, the mask layer 30 is formed to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0169] Furthermore, an insulating layer 35 may be formed on the surface of the porous layer 12 within at least one element region. In this case, it is preferable that the insulating layer 35 be formed away from the mask layer 30. The insulating layer 35 may also be formed on the surface of the dielectric layer 13 on the porous layer 12. It is preferable that the insulating layer 35 be formed to fill the pores (recesses) of the porous layer 12 or the dielectric layer 13.

[0170] Next, a cathode layer 20 is formed on the surface of the dielectric layer 13 within the element region separated by the mask layer 30. The cathode layer 20 may also be formed to extend to the surface of the mask layer 30.

[0171] The step of forming the cathode layer 20 includes the step of forming a solid electrolyte layer 21 containing a conductive polymer on the surface of the dielectric layer 13.

[0172] Figure 21 is a schematic perspective view showing an example of the process for forming a solid electrolyte layer. Figure 22 is an enlarged cross-sectional view of the portion enclosed by the dashed line in the anode plate shown in Figure 21.

[0173] As shown in Figure 21, a solid electrolyte layer 21 is formed on the surface of the dielectric layer 13 within the element region separated by the mask layer 30.

[0174] The process of forming the solid electrolyte layer 21 includes the steps of forming a first conductive polymer layer 21A (see Figure 9), forming a second conductive polymer layer 21B (see Figure 10), and forming a third conductive polymer layer 21C (see Figures 11 and 12). The process of forming the solid electrolyte layer 21 is common to the method for manufacturing a solid electrolytic capacitor of the present invention, so details are omitted.

[0175] In sheet-like capacitor arrays with many interfaces between dissimilar materials and where the thickness dimension is smaller than the plane dimension, delamination due to stress is likely to occur. Therefore, in order to enhance the anchoring effect in the pore areas, it is preferable to minimize the amount of conductive polymer coated in the solid electrolyte layer 21.

[0176] The step of forming the cathode layer 20 preferably further includes the step of forming a conductive layer 22 on the surface of the solid electrolyte layer 21.

[0177] The step of forming the conductive layer 22 includes, for example, the step of forming a first conductive layer 22A on the surface of the solid electrolyte layer 21, and the step of forming a second conductive layer 22B on the surface of the first conductive layer 22A.

[0178] Figure 23 is a schematic perspective view showing an example of the process for forming the first conductive layer.

[0179] As shown in Figure 23, a first conductive layer 22A is formed on the surface of the solid electrolyte layer 21. The first conductive layer 22A is, for example, a conductive resin layer containing a conductive filler.

[0180] Figure 24 is a schematic perspective view showing an example of the process for forming the second conductive layer.

[0181] As shown in Figure 24, a second conductive layer 22B is formed on the surface of the first conductive layer 22A. This forms the conductive layer 22. The second conductive layer 22B is, for example, a conductive resin layer containing a metal filler. Thus, the step of forming the conductive layer 22 may include the step of forming a conductive resin layer containing a metal filler.

[0182] As an example, the conductive layer 22 includes a carbon layer as the first conductive layer 22A and a copper layer as the second conductive layer 22B.

[0183] Figure 25 is a schematic perspective view showing an example of the process of dividing an anode plate on which a cathode layer has been formed.

[0184] As shown in Figure 25, the anode plate 10 on which the cathode layer 20 is formed is divided into element regions, thereby separating it into multiple capacitor elements 110.

[0185] Methods for dividing the anode plate 10 on which the cathode layer 20 is formed include, for example, laser processing and dicing.

[0186] As shown in Figure 25, it is preferable to electrically separate the anode plate 10 between at least one pair of adjacent capacitor elements 110. That is, it is preferable to separate the anode plate 10 between at least one pair of adjacent capacitor elements 110 so as to penetrate through in the thickness direction.

[0187] When forming the insulating layer 35, a through-hole conductor 60 may be formed that penetrates the insulating layer 35 in the thickness direction. As the through-hole conductor 60, for example, a first through-hole conductor 61 may be formed inside the first through-hole 71, or a second through-hole conductor 62 may be formed inside the second through-hole 72.

[0188] Figure 26 is a schematic perspective view showing an example of the process for forming the second through-hole.

[0189] As shown in Figure 26, a second through-hole 72 is formed in the insulating layer 35 in the thickness direction, if necessary.

[0190] Methods for forming the second through-hole 72 include, for example, laser processing and drilling.

[0191] Figure 27 is a schematic perspective view showing an example of the process for forming a sealing layer.

[0192] As shown in Figure 27, for example, an insulating material is provided by press forming or the like to form a sealing layer 40 so as to cover a plurality of capacitor elements 110. The sealing layer 40 is formed so as to cover the cathode layer 20, the mask layer 30 and the insulating layer 35. The sealing layer 40 may be formed to cover both main surfaces of the anode plate 10, or to cover either one of the main surfaces of the anode plate 10.

[0193] The sealing layer 40 may be formed so that it fills the space between adjacent capacitor elements 110. The sealing layer 40 ensures that the anode plates 10 are securely separated from each other.

[0194] Furthermore, if a second through-hole 72 is formed, the sealing layer 40 may be filled into the second through-hole 72.

[0195] Figure 28 is a schematic perspective view showing an example of the process of forming the first through-hole.

[0196] As shown in Figure 28, a first through-hole 71 is formed in the insulating layer 35 in the thickness direction, if necessary. The diameter of the first through-hole 71 is smaller than the diameter of the second through-hole 72.

[0197] Methods for forming the first through-hole 71 include, for example, laser processing and drilling.

[0198] As shown in Figure 28, a third through-hole 73 may be formed, having a smaller diameter than the second through-hole 72. The diameter of the third through-hole 73 may be the same as the diameter of the first through-hole 71, larger than the diameter of the first through-hole 71, or smaller than the diameter of the first through-hole 71.

[0199] Methods for forming the third through-hole 73 include, for example, laser processing and drilling.

[0200] Figure 29 is a schematic perspective view showing an example of the process for forming a through-hole conductor.

[0201] As shown in Figure 29, a first through-hole conductor 61 is formed inside the first through-hole 71, and a second through-hole conductor 62 is formed inside the second through-hole 72.

[0202] The first through-hole conductor 61 is formed to penetrate the capacitor element 110 and the sealing layer 40 in the thickness direction. Preferably, the first through-hole conductor 61 is electrically connected to the anode plate 10 at the inner wall of the first through-hole 71. In the example shown in Figure 29, the first through-hole conductor 61 is formed to fill the first through-hole 71, but it is sufficient that the first through-hole conductor 61 is formed at least on the inner wall surface of the first through-hole 71.

[0203] The second through-hole conductor 62 is formed to penetrate the capacitor element 110 and the sealing layer 40 in the thickness direction. Preferably, the second through-hole conductor 62 is electrically insulated from the anode plate 10 by the inner wall of the second through-hole 72. In the example shown in Figure 29, the second through-hole conductor 62 is formed to fill the third through-hole 73, but it is sufficient that the second through-hole conductor 62 is formed on at least the inner wall surface of the third through-hole 73.

[0204] As shown in Figure 29, a sealing layer 40 may be filled between the second through-hole conductor 62 and the anode plate 10. The sealing layer 40 ensures that the second through-hole conductor 62 is reliably insulated from the anode plate 10 at the inner wall of the second through-hole 72.

[0205] Figure 30 is a schematic perspective view showing an example of the process of forming a via conductor.

[0206] As shown in Figure 30, via conductors 50 may be formed in the sealing layer 40.

[0207] Through the above process, the capacitor array 100 shown in Figures 17 and 18 can be manufactured.

[0208] As described above, when manufacturing the capacitor array of the present invention, methods for dividing the anode plate 10 on which the cathode layer 20 is formed include laser processing and dicing. In particular, by using laser processing, the element region can be formed into any shape. Therefore, it becomes possible to arrange two or more capacitor elements with different element region areas in one capacitor array, to arrange slits so as not to cover the entire capacitor array, and to arrange capacitor elements whose cathode layer planar shape is not rectangular.

[0209] [Composite Electronic Components] The capacitor array of the present invention can be suitably used as a component material for a composite electronic component. Such a composite electronic component comprises, for example, the capacitor array of the present invention, external electrodes provided outside the capacitor array and connected to the anode plate and cathode layer of the capacitor element, respectively, and an electronic component connected to the external electrodes.

[0210] In a composite electronic component, the electronic component connected to the external electrode may be a passive element or an active element. Both passive and active elements may be connected to the external electrode, or either one of the passive or active elements may be connected to the external electrode. Furthermore, a composite of passive and active elements may be connected to the external electrode.

[0211] Examples of passive components include inductors. Examples of active components include memory, GPUs (Graphical Processing Units), CPUs (Central Processing Units), MPUs (Micro Processing Units), and PMICs (Power Management ICs).

[0212] The capacitor array of the present invention has a sheet-like shape as a whole. Therefore, in a composite electronic component, the capacitor array can be treated like a mounting substrate, and electronic components can be mounted on the capacitor array. Furthermore, by making the shape of the electronic components mounted on the capacitor array a sheet shape, it is also possible to connect the capacitor array and the electronic components in the thickness direction via through-hole conductors that penetrate through each electronic component in the thickness direction. As a result, active and passive elements can be configured as a single module.

[0213] For example, a switching regulator can be formed by electrically connecting the capacitor array of the present invention between a voltage regulator including semiconductor active elements and a load to which the converted DC voltage is supplied.

[0214] In a composite electronic component, a circuit layer may be formed on one side of a capacitor matrix sheet on which multiple capacitor arrays of the present invention are further laid out, and then connected to a passive element or an active element.

[0215] Alternatively, the capacitor array of the present invention may be placed in a cavity pre-formed on the substrate, embedded in resin, and then a circuit layer may be formed on the resin. Another electronic component (passive or active element) may be mounted in another cavity on the same substrate.

[0216] Alternatively, the capacitor array 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 it may be connected to a passive or active element. [Examples]

[0217] The following are examples that more specifically disclose the solid electrolytic capacitor and the method for manufacturing the solid electrolytic capacitor of the present invention. However, the present invention is not limited to these examples.

[0218] (Example 1) An aluminum sheet having a porous layer and an oxide film on both sides was prepared, and an insulating resin was used to form a mask layer surrounding the effective portion (element region) which would become the capacitance portion of the capacitor element, and an insulating layer for forming through-hole conductors within the effective portion by coating. A conductive polymer ink containing a self-doped first conductive polymer, represented as poly(3,4-ethylenedioxythiophene) and soluble in a solvent, was applied to the formed effective portion, and the drying process was repeated multiple times to form a first conductive polymer layer on the surface of the dielectric layer.

[0219] Next, a second conductive polymer layer was formed by simultaneously applying a dispersion containing a non-self-doped second conductive polymer and a solution containing an insulating material that suppresses thermal and oxidative degradation of the conductive polymer, followed by drying, multiple times. This process formed a second conductive polymer layer in which insulating material was interspersed within continuous conductive regions. The second conductive polymer used was represented as poly(3,4-ethylenedioxythiophene), which had a larger particle size than the first conductive polymer, was insoluble in solvents, but possessed high heat resistance. As the insulating material, a phenolic material was used that supplied hydrogen radicals (H·) to stabilize radicals (R·) generated in the molecular chain of the conductive polymer due to heat, and peroxy radicals (ROO·) generated by the reaction of the above radicals (R·) with oxygen.

[0220] Next, a third conductive polymer layer was formed by applying a third conductive polymer to the effective portion, thereby forming a solid electrolyte layer. Subsequently, a first conductive layer and a second conductive layer were formed as conductive layers by coating. A carbon layer was formed as the first conductive layer, and a copper layer was formed as the second conductive layer. A solid electrolytic capacitor sheet was thus obtained.

[0221] By attaching resin sheets to the top and bottom surfaces of the obtained solid electrolytic capacitor sheet and pressing them together, a capacitor array sheet with a smooth surface was obtained.

[0222] After cutting the capacitor array sheet so that each capacitor element was independent, the resulting grooves (slits) were filled by pressing a resin sheet onto them again.

[0223] A hole was formed from a sealing layer made of a resin sheet toward a second conductive layer, and the inside of the formed hole was filled with a conductive material to form a via conductor.

[0224] The capacitor array sheet obtained as described above was cut into individual pieces to obtain the solid electrolytic capacitor of Example 1.

[0225] Figure 31 is a schematic cross-sectional view showing a portion of the solid electrolyte layer constituting the solid electrolytic capacitor of Example 1.

[0226] As shown in Figure 31, in the solid electrolytic capacitor of Example 1, a first conductive polymer layer 21A is provided inside the pores of the dielectric layer 13, and a second conductive polymer layer 21B is provided inside the pores of the dielectric layer 13, covering the first conductive polymer layer 21A. The first conductive polymer layer 21A is a layer containing a self-doped first conductive polymer, and the second conductive polymer layer 21B is a layer in which a non-self-doped second conductive polymer and an insulating material are mixed.

[0227] (Comparative Example 1) An aluminum sheet having a porous layer and an oxide film on both sides was prepared, and a mask layer surrounding the effective portion (element region) which would become the capacitance portion of the capacitor element was formed by coating with an insulating resin. A conductive polymer ink containing a self-doped first conductive polymer was applied to the formed effective portion, and the drying process was repeated multiple times to form a first conductive polymer layer on the surface of the dielectric layer.

[0228] Next, a dispersion of a non-self-doped second conductive polymer was applied and dried multiple times to form a second conductive polymer layer on the surface of the dielectric layer. Subsequently, an insulating material layer was formed on the surface of the second conductive polymer layer, where the conductive regions were continuous, by applying a solution containing a dissolved insulating material that suppresses thermal and oxidative degradation of the conductive polymer and drying multiple times.

[0229] Subsequently, a third conductive polymer layer, a first conductive layer, and a second conductive layer were formed in the same manner as in Example 1 to produce a solid electrolytic capacitor sheet, and a capacitor array was fabricated using the solid electrolytic capacitor sheet. The obtained capacitor array sheet was cut into individual pieces to obtain the solid electrolytic capacitor of Comparative Example 1.

[0230] Figure 32 is a schematic cross-sectional view showing a portion of the solid electrolyte layer constituting the solid electrolytic capacitor of Comparative Example 1.

[0231] As shown in Figure 32, in the solid electrolytic capacitor of Comparative Example 1, a first conductive polymer layer 21A is provided inside the pores of the dielectric layer 13, and a second conductive polymer layer 21B is provided inside the pores of the dielectric layer 13, covering the first conductive polymer layer 21A. The first conductive polymer layer 21A is a layer containing a self-doped first conductive polymer, and the second conductive polymer layer 21B is a layer containing a non-self-doped second conductive polymer. In addition, in the solid electrolytic capacitor of Comparative Example 1, an insulating material layer 25 is provided so as to cover the second conductive polymer layer 21B. The insulating material layer 25 is a layer containing an insulating material.

[0232] (Comparative Example 2) An aluminum sheet having a porous layer and an oxide film on both sides was prepared, and a mask layer surrounding the effective portion (element region) which would become the capacitance part of the capacitor element was formed by coating with an insulating resin. A dispersion liquid containing a non-self-doped second conductive polymer was applied to the formed effective portion, and the drying process was repeated multiple times to form a second conductive polymer layer on the surface of the dielectric layer.

[0233] Subsequently, a third conductive polymer layer, a first conductive layer, and a second conductive layer were formed in the same manner as in Example 1 to produce a solid electrolytic capacitor sheet, and a capacitor array was fabricated using the solid electrolytic capacitor sheet. The obtained capacitor array sheet was cut into individual pieces to obtain the solid electrolytic capacitor of Comparative Example 2.

[0234] Figure 33 is a schematic cross-sectional view showing a portion of the solid electrolyte layer constituting the solid electrolytic capacitor of Comparative Example 2.

[0235] As shown in Figure 33, in the solid electrolytic capacitor of Comparative Example 2, a second conductive polymer layer 21B is provided inside the pores of the dielectric layer 13. The second conductive polymer layer 21B is a layer containing a non-self-doped second conductive polymer.

[0236] The ESR of the solid electrolytic capacitors in Example 1, Comparative Example 1, and Comparative Example 2 was measured at room temperature and 100 kHz using an LCR meter.

[0237] Figure 34 is a graph showing the ESR of the solid electrolytic capacitors in Example 1 and Comparative Example 1.

[0238] As shown in Figure 34, the solid electrolytic capacitor of Example 1 has a lower ESR than the solid electrolytic capacitor of Comparative Example 1.

[0239] The ESR change rate at 100kHz was measured for the solid electrolytic capacitors of Example 1, Comparative Example 1, and Comparative Example 2 when left in air at 150°C.

[0240] Figure 35 is a graph showing the ESR change rate of solid electrolytic capacitors in Example 1 and Comparative Example 2.

[0241] As shown in Figure 35, the ESR change rate of the solid electrolytic capacitor in Example 1 is smaller than that of the solid electrolytic capacitor in Comparative Example 2.

[0242] The capacitance of the solid electrolytic capacitors in Example 1, Comparative Example 1, and Comparative Example 2 was measured at room temperature and 120 Hz using an LCR meter.

[0243] Figure 36 is a graph showing the capacitance of the solid electrolytic capacitors in Example 1 and Comparative Example 2.

[0244] As shown in Figure 36, the solid electrolytic capacitor of Example 1 has a higher capacitance than the solid electrolytic capacitor of Comparative Example 2. [Explanation of Symbols]

[0245] 1, 1A, 1B Solid electrolytic capacitors 10 Anode plate 11 Core 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 Conductive layer 22A First conductive layer 22B Second conductive layer 25 Insulating material layer 30 mask layers 35 Insulating layer 40 sealing layer 50 via conductors 60 Through-hole conductors 61 First through-hole conductor 62 Second through-hole conductor 71 First through hole 72 Second through hole 73 Third through hole 100 Capacitor Array 110 Capacitor element

Claims

1. A step of preparing an anode plate having a core, a porous layer provided on at least one main surface of the core, and a dielectric layer provided on the surface of the porous layer, The process includes forming a cathode layer on the surface of the dielectric layer, The step of forming the cathode layer includes the step of forming a solid electrolyte layer containing a conductive polymer on the surface of the dielectric layer, The step of forming the solid electrolyte layer includes the steps of forming a first conductive polymer layer inside the pores of the dielectric layer, forming a second conductive polymer layer inside the pores of the dielectric layer that covers the first conductive polymer layer, and forming a third conductive polymer layer on the surface of the anode plate that covers at least the second conductive polymer layer. In the step of forming the first conductive polymer layer, a liquid containing the first conductive polymer is used to form the layer containing the first conductive polymer. A method for manufacturing a solid electrolytic capacitor, wherein in the step of forming the second conductive polymer layer, a liquid in which a second conductive polymer having a larger particle size than the first conductive polymer is dispersed, and a liquid containing an insulating material that suppresses thermal and oxidative degradation of the conductive polymer contained in the solid electrolyte layer are used to form a layer in which the second conductive polymer and the insulating material are mixed.

2. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the second conductive polymer layer is formed by simultaneously applying a liquid in which the second conductive polymer is dispersed and a liquid containing the insulating material.

3. The method for manufacturing a solid electrolytic capacitor according to claim 2, wherein the first conductive polymer layer is formed by applying a liquid containing the first conductive polymer.

4. The method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 3, wherein the first conductive polymer layer is formed using a liquid in which the first conductive polymer is dissolved.

5. A method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 4, wherein the first conductive polymer is self-doped and the second conductive polymer is unself-doped.

6. A method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 5, wherein the weight ratio of the solid content of the insulating material to the second conductive polymer is 1 / 10 or more and 10 / 1 or less.

7. The method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 6, wherein the step of forming the cathode layer further includes the step of forming a conductive layer on the surface of the solid electrolyte layer.

8. The method for manufacturing a solid electrolytic capacitor according to claim 7, wherein the step of forming the conductive layer includes the step of forming a conductive resin layer containing a metal filler.

9. A method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 8, further comprising the step of forming a mask layer on the surface of the porous layer so as to surround the region on the anode plate where the cathode layer is to be formed.

10. A step of preparing an anode plate having a core, a porous layer provided on at least one main surface of the core, and a dielectric layer provided on the surface of the porous layer, The anode plate is divided into multiple element regions by forming a mask layer on the surface of the porous layer, A step of forming a cathode layer on the surface of the dielectric layer within the element region separated by the mask layer, The process of separating the anode plate on which the cathode layer is formed into a plurality of capacitor elements by dividing the element region, The process includes a step of forming a sealing layer so as to cover the plurality of capacitor elements, The step of forming the cathode layer includes the step of forming a solid electrolyte layer containing a conductive polymer on the surface of the dielectric layer, The step of forming the solid electrolyte layer includes the steps of forming a first conductive polymer layer inside the pores of the dielectric layer, forming a second conductive polymer layer inside the pores of the dielectric layer that covers the first conductive polymer layer, and forming a third conductive polymer layer on the surface of the anode plate that covers at least the second conductive polymer layer. In the step of forming the first conductive polymer layer, a liquid containing the first conductive polymer is used to form the layer containing the first conductive polymer. A method for manufacturing a capacitor array, wherein in the step of forming the second conductive polymer layer, a liquid in which a second conductive polymer having a larger particle size than the first conductive polymer is dispersed, and a liquid containing an insulating material that suppresses thermal and oxidative degradation of the conductive polymer contained in the solid electrolyte layer are used to form a layer in which the second conductive polymer and the insulating material are mixed.

11. A step of forming an insulating layer on the surface of the porous layer within the element region, A method for manufacturing a capacitor array according to claim 10, further comprising the step of forming a through-hole conductor that penetrates the insulating layer in the thickness direction.

12. The step of forming the through-hole conductor includes the steps of forming a first through-hole that penetrates the insulating layer in the thickness direction, and forming a first through-hole conductor inside the first through-hole. The method for manufacturing a capacitor array according to claim 11, wherein the first through-hole conductor is electrically connected to the anode plate at the inner wall of the first through-hole.

13. The step of forming the through-hole conductor includes the steps of forming a second through-hole that penetrates the insulating layer in the thickness direction, and forming a second through-hole conductor inside the second through-hole. The method for manufacturing a capacitor array according to claim 11 or 12, wherein the second through-hole conductor is electrically insulated from the anode plate by the inner wall of the second through-hole.

14. an anode plate having a core, a porous layer provided on at least one main surface of the core, and a dielectric layer provided on the surface of the porous layer, The dielectric layer comprises a cathode layer provided on the surface of the dielectric layer, The cathode layer is provided on the surface of the dielectric layer and includes a solid electrolyte layer containing a conductive polymer. The solid electrolyte layer includes a first conductive polymer layer provided inside the pores of the dielectric layer, a second conductive polymer layer provided inside the pores of the dielectric layer and covering the first conductive polymer layer, and a third conductive polymer layer provided on the surface of the anode plate and covering at least the second conductive polymer layer. The first conductive polymer layer is a layer containing a self-doped first conductive polymer, The solid electrolytic capacitor is a layer in which a non-self-doped second conductive polymer and an insulating material that suppresses thermal and oxidative degradation of the conductive polymer contained in the solid electrolyte layer are mixed.

15. The solid electrolytic capacitor according to claim 14, wherein at least one of the conductive polymers contained in the solid electrolyte layer is present in a region within 5 μm where the insulating material is present.

16. A portion of the first conductive polymer layer and / or a portion of the second conductive polymer layer are exposed on the surface of the anode plate. The solid electrolytic capacitor according to claim 14 or 15, wherein the area of ​​the region on the surface of the anode plate in which the first conductive polymer layer and the second conductive polymer layer are not present is larger than the area of ​​the region on the surface of the anode plate in which the first conductive polymer layer and the second conductive polymer layer are present.

17. A solid electrolytic capacitor according to any one of claims 14 to 16, wherein a portion of the third conductive polymer layer is embedded inside the pores of the dielectric layer.

18. The solid electrolytic capacitor according to any one of claims 14 to 17, wherein the cathode layer further comprises a conductive layer provided on the surface of the solid electrolyte layer.

19. The solid electrolytic capacitor according to claim 18, wherein the conductive layer includes a conductive resin layer containing a metal filler.

20. Multiple capacitor elements, The system comprises a sealing layer provided to cover the plurality of capacitor elements, A capacitor array in which each of the plurality of capacitor elements is a solid electrolytic capacitor according to any one of claims 14 to 19.

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