JP2007109722A - Process for fabricating solid electrolytic capacitor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for fabricating a solid electrolytic capacitor excellent in electric characteristics and having a masking structure which can prevent chemical conversion treatment liquid from oozing up to the positive electrode of the solid electrolytic capacitor during chemical conversion treatment, and can insulate solid electrolyte (negative electrode portion) formed in a subsequent process from the positive electrode certainly. <P>SOLUTION: In the process for fabricating a solid electrolytic capacitor element comprising a step for forming a masking on a part of a positive electrode substrate having a dielectric film on the surface to section that surface, and forming a solid electrolyte layer in at least a partial region on the surface of the positive electrode substrate sectioned by masking, a step performing formation processing in a region including the fringe of masking after forming the masking is included. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a solid electrolytic capacitor element, a solid electrolytic capacitor element produced by this method, and a solid electrolytic capacitor using this element. More specifically, when a solid electrolyte layer is formed on a valve action metal substrate having a dielectric film, the metal substrate portion (anode portion) where the solid electrolyte layer is not provided and the solid electrolyte layer or further a conductive paste or the like thereon A method for producing a solid electrolytic capacitor element having a masking structure that can reliably insulate the conductor layer (cathode part) formed by the above-mentioned method and having excellent electrical characteristics, a solid electrolytic capacitor element produced by this method, and this element The present invention relates to a solid electrolytic capacitor used.

As shown in FIG. 1, a solid electrolytic capacitor using a conductive polymer is formed by forming a dielectric oxide film 2 on an anode substrate 1 and forming a conductive polymer on the dielectric oxide film 2 to form a solid electrolyte. The layer 4 has a basic structure (solid electrolytic capacitor element) in which a conductive paste or the like is further attached as necessary. Masking 4 is provided between the anode part (anode base part having no solid electrolyte) and the cathode part (conductor layer containing a conductive polymer) to insulate the negative and positive electrode parts.
The solid electrolytic capacitor element can be used as it is or after a plurality of layers are laminated, and the anode lead wire is connected to the anode portion, the cathode lead wire is connected to the cathode portion, and the whole is sealed with an insulating resin such as epoxy resin. Produced. Such a solid electrolytic capacitor using a conductive polymer as a solid electrolyte can reduce the equivalent series resistance and leakage current compared to a solid electrolytic capacitor using manganese dioxide or the like as a solid electrolyte, thereby improving the performance and size of electronic equipment. It is useful as a capacitor that can cope with the manufacturing process, and many manufacturing methods have been proposed.

  In order to produce a high-performance solid electrolytic capacitor using a conductive polymer, the anode part serving as the anode terminal and the cathode part formed of the conductive layer containing the conductive polymer must be electrically insulated reliably. Is essential. As a masking means for insulating the anode part and the cathode part of the solid electrolytic capacitor, for example, a method of preventing conduction by applying epoxy, phenol resin, etc. to an unformed part, printing or spotting, and curing it (Japanese Patent Laid-Open No. 3-95910) Publication: Patent Document 1), a polyamic acid film is formed by electrodeposition of a solution containing a polyamic acid salt on at least part of a portion of a valve metal that does not form a solid electrolyte, and then dehydrated and cured by heating to form a polyimide. A method of forming a film (Japanese Patent Laid-Open No. 5-47611; Patent Document 2), forming a tape or a resin-coated film portion made of polypropylene, polyester, silicon-based resin or fluorine-based resin to prevent the solid electrolyte from creeping up A method (Japanese Patent Laid-Open No. 5-166681; Patent Document 3), a portion serving as an anode terminal of a metal substrate, A method in which an insulating resin layer is formed on the surface of a boundary portion with a portion where a capacitor is formed, and then a portion of the insulating resin layer other than the capacitor is removed to expose the metal substrate (Japanese Patent Laid-Open No. 9-36003; Patent Document 4) ) Etc. have been proposed.

  In addition, in the international publication 00/67267 pamphlet (Patent Document 5), the applicant of the present invention has a metal substrate portion (anode portion) not provided with a solid electrolyte layer and a conductor layer provided with a solid electrolyte layer or a conductive paste on the solid electrolyte layer (anode portion). The present invention provides a solid electrolytic capacitor having a masking structure capable of reliably insulating the cathode portion) and a method for manufacturing the same, and a masking material capable of efficiently performing masking capable of reliably insulating the anode portion and the cathode portion of the solid electrolytic capacitor A coating method and apparatus therefor were provided.

  In these conventional techniques, masking for insulating a metal substrate portion (anode portion) not provided with a solid electrolyte layer and a conductor layer (cathode portion) provided with a solid electrolyte layer or a conductive paste on the solid electrolyte layer is a valve action metal. In this method, a non-formed part or a formed part is applied by coating or the like, and then a solid electrolyte such as a conductive polymer is formed on the cathode part. However, when the masking layer is formed, especially when the masking layer is formed on the chemical conversion part, the oxide film is damaged during the process of applying the masking material, applying the tape, or subsequent heat treatment, and the electrical characteristics, particularly the reflow. The problem of affecting the leakage current later has not been completely solved, and further improvements have been demanded.

Japanese Patent Laid-Open No. 3-95910 JP-A-5-47611 JP-A-5-166681 Japanese Patent Laid-Open No. 9-36003 International Publication No. 00/67267 Pamphlet

  An object of the present invention is to provide a solid electrolytic capacitor manufacturing method in which a solid electrolyte layer is formed on a valve-acting metal substrate having a dielectric film, and a metal substrate portion (anode portion) not provided with a solid electrolyte layer and a solid electrolyte layer An object of the present invention is to provide a method for manufacturing a solid electrolytic capacitor having a masking structure capable of reliably insulating a conductive layer (cathode portion) provided with a conductive paste or the like on top and having excellent electrical characteristics.

  The present inventor forms a mask that insulates a metal substrate portion (anode portion) not provided with a solid electrolyte layer and a solid electrolyte layer or a conductor layer (cathode portion) provided with a conductive paste or the like thereon, and then performs the masking. It has been found that a capacitor element excellent in leakage current and reflow characteristics can be formed by subjecting the peripheral portion to chemical conversion, and the present invention has been completed. That is, the present invention provides the following method for producing a solid electrolytic capacitor element, a solid electrolytic capacitor element produced by this method, and a solid electrolytic capacitor using this element.

1. Forming a mask on a part of the anode base material having a dielectric film on the surface so as to partition the surface, and forming a solid electrolyte layer in at least a part of the surface of the anode base material defined by the masking. A method for manufacturing a solid electrolytic capacitor element, comprising: performing a chemical conversion treatment on a region including a masking edge after the masking is formed.
2. A first masking is formed on a part of the anode base material having a dielectric film on the surface so as to partition the surface, and a solid electrolyte layer is formed on a part of the surface of the anode base material defined by the first masking. In the method of manufacturing a solid electrolytic capacitor element including the step of: forming a second mask so as to partition a region where a solid electrolyte layer is to be formed, and after forming the first and second masks, at least an edge of the second masking The manufacturing method of the solid electrolytic capacitor element characterized by including the process of performing a chemical conversion treatment to the area | region containing a part.
3. 3. The method for producing a solid electrolytic capacitor element as described in 2 above, wherein after the first masking is formed, a chemical conversion treatment is applied to the region including the edge of the first masking.
4). 4. The method for producing a solid electrolytic capacitor element as described in 2 or 3 above, wherein after the second masking is formed, a chemical conversion treatment is applied to the entire region including the second masking and the edge of the first masking.
5. In a region between the first masking and the second masking, the chemical conversion treatment is performed on the region including the edge of the second masking, and then a solid electrolyte layer is formed in the region partitioned by the second masking. The manufacturing method of the solid electrolytic capacitor element in any one of said 2-4 including the process of cut | disconnecting.
6). 6. The method for producing a solid electrolytic capacitor element according to any one of 1 to 5, wherein masking is formed by applying a masking material solution.
7). 7. The method for producing a solid electrolytic capacitor element as described in 6 above, wherein the masking material solution penetrates into the dielectric film and forms a masking layer on the penetration part.
8). 8. The method for producing a solid electrolytic capacitor element as described in 7 above, wherein the masking material solution is a solution of a heat resistant resin or a precursor thereof.
9. 9. The method for producing a solid electrolytic capacitor element as described in 8 above, wherein the solution of the heat resistant resin or precursor thereof is a low molecular weight polyimide solution or a polyamic acid solution which is solidified by heating.
10. 10. The method for producing a solid electrolytic capacitor as described in 9 above, wherein the masking material solution further contains silicone oil, a silane coupling agent or polyimide siloxane.
11. 11. The method for producing a solid electrolytic capacitor element as described in any one of 1 to 10 above, wherein the anode substrate is a valve metal having a porous layer on the surface.
12 12. The method for producing a solid electrolytic capacitor element as described in 11 above, wherein the metal material having a valve action is a material selected from aluminum, tantalum, niobium, titanium, zirconium and alloys thereof.
13. 13. The solid electrolysis according to any one of 1 to 12, wherein the solid electrolyte is a polymer solid electrolyte containing at least one of a divalent group containing pyrrole, thiophene, aniline, and furan skeleton or a substituted derivative thereof as a repeating unit. A method for manufacturing a capacitor element.
14 14. The method for producing a solid electrolytic capacitor element as described in 13 above, wherein the polymer solid electrolyte contains a polymer of 3,4-ethylenedioxythiophene.
15. 15. The method for producing a solid electrolytic capacitor element according to any one of 1 to 14, wherein the solid electrolyte further contains an aryl sulfonate dopant.
16. The solid electrolytic capacitor element manufactured by the manufacturing method of the solid electrolytic capacitor element in any one of said 1-15.
17. 17. A solid electrolytic capacitor comprising the solid electrolytic capacitor element as described in 16 above.

  According to the present invention, after masking formation, the periphery of the masking is subjected to chemical treatment, thereby repairing the damage to the dielectric film due to the masking formation, reducing leakage current, and improving leakage current characteristics after reflow. it can.

Hereinafter, the present invention will be described in detail.
In the present invention, a mask is formed on a part of the anode base material having a dielectric film on the surface so as to partition the surface, and the solid electrolyte layer is formed on at least a part of the anode base material surface partitioned by the masking. In the method of manufacturing a solid electrolytic capacitor element including the step of forming, the method includes a step of performing a chemical conversion treatment on a region including an edge portion of the masking after the masking is formed. For example, in the case of the solid electrolytic capacitor element having the cross-sectional structure of FIG. 1, after the masking 3 is formed, the region including the edge thereof, preferably the region including the entire masking 3 is subjected to chemical conversion treatment to form the dielectric film 2 by masking formation. The solid electrolyte layer 4 is formed after repairing the damage that has occurred.

The present invention can be particularly suitably applied to a method of manufacturing a solid electrolytic capacitor element in which the masking process is performed twice.
As an example of such a method, the manufacturing method of the solid electrolytic capacitor element of the rectangular foil shape which this applicant disclosed in patent document 5 is mentioned. An outline of this method is shown in FIG.
In this method, the first masking 3a is formed on the upper part of the strip-shaped base material 1 obtained by cutting the tape-shaped base material, and then the chemical conversion layer 2 is formed in order to form the cut surface at the time of cutting. Further, the second masking 3b is formed below the first masking 3a. Next, the solid electrolyte layer 4 is formed in the lower part of the region partitioned by the second masking 3b, and cutting is performed between the first masking 3a and the second masking 3b. The rectangular portion including the second masking 3b has a cross section (cross section cut in the vertical direction in the drawing) shown in FIG. 1, and the solid electrolytic capacitor element is formed by the above operation.

When the present invention is applied to this method, it is characteristic that a chemical conversion treatment is further performed after the second masking.
That is, as shown in FIG. 3, the first masking 3a is formed on the upper surface of the strip-shaped base material 1 obtained by cutting the tape-shaped base material in a circumferential shape across the front and back of the base material, and then, at the time of cutting The chemical conversion layer 2 is formed in order to form the cut surface, and further, the second masking 3b is formed in a circumferential shape across the front and back surfaces of the base material below the first masking 3a. Up to this point, it may be the same as the method described in Patent Document 5 (however, in order to distinguish it from the chemical conversion of the present invention described later, the formation stage of the chemical conversion layer 2 is shown as chemical conversion treatment I), but in the present invention the second masking is performed. Chemical conversion treatment (chemical conversion treatment) is performed on the region including the edge of 3b, preferably the region covering the entire second masking 3b, more preferably the entire region including the second masking 3b among the regions partitioned by the first masking 3a. Perform II). Next, the solid electrolyte layer 4 is formed in the lower part of the region partitioned by the second masking 3b, and cutting is performed between the first masking 3a and the second masking 3b. The rectangular portion including the second masking 3b has a cross section (cross section cut in the vertical direction in the figure) as shown in FIG. 1, and a solid electrolytic capacitor element is formed by the above operation.

  In the example shown in FIG. 3, the chemical conversion treatment II is performed over the entire surface from the second masking 3 b to the edge of the base material. However, the chemical conversion treatment II may be performed on a region including the edge portion of the second masking. Preferably, the second masking is performed on a region covering the entire second masking. Therefore, preferably, as shown in FIG. 4, the chemical conversion treatment II is performed including the region 6 from the upper edge of the second masking to the vicinity of the lower edge of the first masking (or the vicinity thereof).

As described above, the masking that insulates the cathode portion from the anode portion is the second masking. In the present invention, it is important to perform the chemical conversion treatment II after the second masking. Therefore, as shown in FIG. 3 or 4, it is preferable to form the second masking after performing the chemical conversion treatment I before the chemical conversion treatment II, but even if the masking is performed twice, the chemical conversion treatment I Is an optional process. That is, as shown in FIG. 5, after the first masking 3a is formed, the second masking 3b is formed without performing the chemical conversion treatment I, or the first masking 3a and the second masking 3b are simultaneously formed (second masking). The first masking may be formed after the formation of), and a chemical conversion treatment (shown as chemical conversion treatment II but not chemical conversion treatment I) may be performed. The chemical conversion treatment II in this case may also be performed on the region including the edge of the second masking, but preferably in the region covering the entire second masking, more preferably, as shown in FIG. The chemical conversion treatment II is performed including the region 6 from the upper edge to the vicinity of the lower edge of the first masking (or the vicinity thereof). According to this aspect, the chemical conversion treatment I step is omitted, and two masking forming steps ((b) and (c) in the figure) can be simultaneously performed.
Although the masking is linear in the examples shown in FIGS. 3 to 5, the masking may be any shape, for example, a curve, as long as the yin and yang bipolar portions can be insulated.

  The present invention can be applied to the manufacture of any solid electrolytic capacitor element as long as it includes the above features. For example, the masking in the present invention can be performed by any method that realizes insulation between the anode portion and the negative anode, such as application of a masking material, application of a tape, and the like. The chemical conversion treatment and the solid electrolyte layer may be any conventional method. Preferred embodiments thereof will be described below.

[Valve action metal]
The base material of the solid electrolytic capacitor is a valve metal having a dielectric oxide film on the surface. The valve metal is selected from aluminum, tantalum, niobium, titanium, zirconium, or an alloy-based metal foil, rod, or sintered body containing these as a main component.

  These metals have a dielectric oxide film whose surface is oxidized by oxygen in the air, but are roughened by an etching process or the like by a known method in advance. Next, it is preferable to form a dielectric oxide film reliably by chemical conversion according to a conventional method. As the valve action metal, an aluminum foil having an alumina oxide layer is preferably used. It is preferable to use a valve action metal that has been roughened and cut in advance to a size that matches the shape of the solid electrolytic capacitor.

  In the case of a metal foil, a thickness suitable for the purpose of use can be used, but generally a foil having a thickness of about 40 to 150 μm is used. In addition, although the size and shape of the foil vary depending on the application, a rectangular element having a width of about 1 to 50 mm and a length of about 1 to 50 mm is preferable as a flat element unit, and more preferably a width of about 2 to 20 mm and a length of about The width is 2 to 20 mm, more preferably about 2 to 5 mm in width and about 2 to 6 mm in length.

[Chemical conversion treatment]
The chemical conversion treatment of the valve action metal cut into a predetermined shape can be performed by various methods. By performing the chemical conversion treatment in advance, even if a defect occurs in the masking layer, an increase in leakage current is prevented.

The conditions for the chemical conversion treatment are not particularly limited. For example, an electrolytic solution containing at least one of oxalic acid, adipic acid, boric acid, phosphoric acid and the like is used, and the electrolytic solution concentration is 0.05 to 20% by mass. The temperature is 0 to 90 ° C., the current density is 0.1 to 200 mA / cm ² , and the voltage is a numerical value corresponding to the conversion voltage of the film already formed on the conversion foil to be processed, and the conversion time is within 60 minutes. Perform formation. More preferably, the conditions are selected within a range where the electrolytic solution concentration is 0.1 to 15% by mass, the temperature is 20 to 70 ° C., the current density is 1 to 100 mA / cm ² , and the formation time is within 30 minutes.

The conditions of the chemical conversion treatment are suitable as an industrial method, but unless the dielectric oxide film already formed on the surface of the valve metal material is destroyed or deteriorated, the type of electrolyte, concentration of electrolyte, temperature Various conditions such as current density and formation time can be arbitrarily selected.
Before and after the chemical conversion treatment, for example, a phosphoric acid immersion treatment for improving water resistance, a heat treatment for strengthening the film, or an immersion treatment in boiling water can be performed.
The chemical conversion treatment is performed after the masking layer is formed using the following masking material, but may be performed before masking depending on circumstances.

[Masking material]
The masking layer is provided in order to prevent the chemical conversion liquid from spreading into the portion that becomes the anode of the solid electrolytic capacitor during the chemical conversion treatment, and to ensure insulation from the solid electrolyte (cathode portion) formed in a later step. It is As a masking material, a general heat resistant resin, preferably a heat resistant resin which can be dissolved or swelled in a solvent or a precursor thereof, a composition comprising inorganic fine powder and a cellulose resin (Japanese Patent Laid-Open No. 11-80596), etc. Can be used but is not limited to materials. Specific examples include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), low molecular weight polyimides and their Derivatives and the like. Particularly preferred are low molecular weight polyimides, polyethersulfones, fluororesins and their precursors.

  When the masking process is performed twice, the first masking layer is provided to prevent the chemical conversion liquid from spreading to the solid electrolytic capacitor anode portion during the chemical conversion treatment. Therefore, the first masking material is not particularly limited, and the general heat resistant resin described above can be used. As the second masking layer, the same material as the first masking material can be used, but in particular, it has sufficient adhesion and filling properties to the valve action metal and can withstand heat treatment up to about 450 ° C. A polyimide excellent in the thickness is preferable.

  As polyimide, there is conventionally used a solution obtained by dissolving a precursor polyamic acid in a solvent, and after coating, heat treatment is performed at a high temperature to imidize, but heat treatment at 250 to 350 ° C. is required, and anode foil There was a problem such as damage to the dielectric layer on the surface of the substrate due to heat. In the present invention, curing is sufficiently possible by heat treatment at a low temperature of 200 ° C. or less, preferably 100 to 200 ° C., and there is little external impact such as damage or destruction due to heat of the dielectric layer on the surface of the anode foil. Use polyimide.

  Polyimide is a compound having an imide structure in the main chain. In the present invention, a compound having a flexible structure in which intramolecular rotation easily occurs in the skeleton of the diamine component, for example, a compound having an ether bond having no steric hindrance in the molecule. Is mentioned. Examples of such compounds include ULTEM (registered trademark; manufactured by GE Plastics), VESPEL (registered trademark) SP (manufactured by DuPont), Iupimol (registered trademark) R (manufactured by Ube Industries), TORLON (registered trademark; Solvay Advanced). Polymers)). In addition, polyimides obtained by polycondensation reaction of 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride and aromatic diamines can be preferably used. The average molecular weight is preferably about 1,000 to 1,000,000, more preferably about 2,000 to 200,000.

  These can be dissolved or dispersed in an organic solvent, and a solution or dispersion having an arbitrary solid content concentration (and therefore viscosity) suitable for coating operation can be easily prepared. A preferable concentration is about 10 to 60% by mass, and a more preferable concentration is about 15 to 40% by mass. The preferred viscosity is about 50 to 30,000 cP, and the more preferred viscosity is about 500 to 15,000 cP. On the low concentration and low viscosity side, the masking line is blurred, and on the high concentration and high viscosity side, stringing occurs and the line width becomes unstable.

  The masking layer formed by the masking material solution may be subjected to treatments such as drying, heating, and light irradiation as necessary after application of the masking material solution. As a specific example of the polyimide solution, a solution (for example, from Ube Industries, Ltd.) in which a low molecular weight polyimide cured by heat treatment after coating is dissolved in a solvent having low hygroscopicity such as 2-methoxyethyl ether or triethylene glycol dimethyl ether. "Iupicoat (trademark) FS-100L"), or a solution in which the polyimide resin having the sulfonyl group is dissolved in NMP (N-methyl-2-pyrrolidone) or DMAc (dimethylacetamide) (for example, new (Available from Nippon Rika Co., Ltd. as “Rika Coat TM”).

The former is heat-denatured by application of heat treatment at 160 to 180 ° C. after application, is polymerized and cured, and gives a film having flexibility and high heat resistance and insulation. This polyimide film has a tensile strength of 2.0 kg / mm ² , an elongation rate of the cured film of 65%, an initial elastic modulus of 40.6 kg / mm ² , retains rubber-like properties, and has a high thermal decomposition temperature of 461 ° C. have. Even under humidification, the volume resistance is as high as 1016 Ω · cm, the dielectric constant is as low as 3.2, and it retains excellent electrical properties as an insulating coating.

The latter also provides a film having excellent heat resistance, mechanical properties, electrical properties, and chemical resistance simply by removing the solvent at a temperature of 200 ° C. or lower. This film has a heat resistance with a tensile strength of about 11.8 kg / mm ² , an elongation of the cured film of 14.2%, an initial elastic modulus of 274 kg / mm ² or more, a 5% mass reduction temperature of 515 ° C., and a volume resistance Has a dielectric constant of 3.1 (25 ° C.) and 2.8 (200 ° C.), and has excellent electrical characteristics.

  In the present invention, the masking material solution contains an antifoaming agent (lower alcohol, mineral oil, silicone resin, oleic acid, polypropylene glycol, etc.), thixotropic agent (silica fine powder, mica, talc, calcium carbonate, etc.), Resin-modifying silicone agents (such as silane coupling agents, silicone oils, silicone surfactants, silicone synthetic lubricating oils, etc.) can be added. For example, by adding silicone oil (polysiloxane) and a silane coupling agent, defoaming (suppresses foaming during curing), releasability (preventing adhesion of conductive polymer), lubricity (into pores) Penetrability), electrical insulation (leakage current prevention), water repellency (prevention of solution intrusion (liquid rise) during polymerization of conductive polymer), braking / vibration resistance (opposing pressure when capacitor elements are stacked) Improvement of heat resistance and weather resistance of resin (introduction of crosslinking mechanism) can be expected.

  Further, in the present invention, by using a composition comprising a soluble polyimide siloxane and an epoxy resin (Japanese Patent Laid-Open No. 8-253777 (US Pat. No. 5,643,986)), the same effect as the addition of the silicone oil (polysiloxane) is obtained. Can be obtained.

[Method for forming masking layer]
Various methods are known for forming a masking layer, such as application of a masking material and application of a masking tape, and any method can be used in the present invention. Examples of the application of the masking material include a method in which the masking material is applied and transferred to a blade or the like, a method in which the masking material is applied to a roll and transferred (for example, see Patent Document 5), and the like.

[Solid electrolyte]
In the present invention, as the solid electrolyte, a conductive polymer having as a repeating unit at least one divalent group of pyrrole, thiophene, furan or aniline structure, or a substituted derivative thereof can be preferably used. Conventionally known materials can be used without particular limitation.

  For example, a method in which a 3,4-ethylenedioxythiophene monomer and an oxidizing agent are preferably applied in the form of a solution, separately or together, and applied to an oxide film layer of a metal foil (JP-A-2-15611). Gazette (U.S. Pat. No. 4,910,645) and JP-A-10-32145 (European Patent Publication No. 820076 (A2))) can be used.

  The conductive polymer may include an aryl sulfonate dopant. For example, salts such as benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, anthracenesulfonic acid, anthraquinonesulfonic acid, and the like can be used.

  The present invention includes a solid electrolytic capacitor element obtained by the above method. The present invention also includes a solid electrolytic capacitor in which the solid electrolytic capacitor element thus manufactured is laminated as it is, and a cathode lead portion and an anode lead portion are attached and sealed with an epoxy resin or the like.

  The present invention will be described in more detail below with typical examples. Note that these are merely illustrative examples, and the present invention is not limited thereto.

Example 1:
First masking step: 100 μm thick chemically formed aluminum foil cut into 3 mm width (slit) is cut into 18 mm lengths, and one short side of this foil piece is fixed to a metal guide by welding and fixed. A polyimide resin solution (manufactured by Shin Nippon Rika Co., Ltd .; Rika Coat (trademark)) adjusted to a viscosity of 900 cp is supplied to a disc-shaped coating device having a coating surface width of 0.4 mm and coated at a position 7 mm away from the end. The coated surface of the device was in contact with and pressed against the entire circumference of the aluminum formed foil, drawn into a line with a width of 0.8 mm, and dried at about 180 ° C. to form a first masking (polyimide film).

Chemical conversion treatment process I
The aluminum film fixed to the metal guide removed from the coating device and the first masking are immersed in an aqueous solution of ammonium adipate and a voltage of 15 V is applied to form an unformed portion of the cut portion, thereby forming a dielectric film. Formed.

Second masking step Next, the aluminum foil fixed to the metal guide is again attached to the coating apparatus, and a polyimide resin solution (manufactured by Shin Nippon Rika Co., Ltd.) is applied in the same manner as above at a position 4 mm from the unfixed tip. ; Rika Coat (trademark)) was drawn linearly to a width of 0.8 mm and dried at about 180 ° C. to form a second masking (polyimide film).

Chemical conversion process II
The region from the tip of the aluminum foil fixed to the metal guide to the second masking was immersed in an aqueous solution of ammonium adipate and a voltage of 15 V was applied to form a region including the lower edge of the second masking.

Solid electrolyte forming step A solid electrolyte was formed in the chemical conversion treatment layer region excluding the space between the first masking layer and the second masking layer as follows.
That is, the portion (3 mm × 4 mm) opposite to the first masking with the 4 mm second masking from the tip of the aluminum foil as a boundary is an isopropanol solution (solution 1) containing 20% by mass of 3,4-ethylenedioxythiophene. It was immersed, pulled up and left at 25 ° C. for 10 minutes. Next, the aluminum foil part treated with the monomer solution was immersed in an aqueous solution (solution 2) containing 25% by mass of an aqueous ammonium persulfate solution, which was dried at 40 ° C. for 10 minutes, and subjected to oxidative polymerization. The operation of immersing in solution 1 and then immersing in solution 2 and conducting oxidative polymerization was repeated 20 times to form a solid electrolyte layer.

Cutting Step After the carbon paste and the silver paste were attached to the portion where the solid electrolyte layer was formed, the aluminum foil was cut between the first masking and the second masking.

Construction and testing of a chip-type solid electrolytic capacitor element Three layers of the cut portion including the second masking layer are joined on the lead frame while being joined with silver paste, and the anode lead terminal is connected to the portion without the conductive polymer by welding. The whole was sealed with an epoxy resin, and a rated voltage was applied at 130 ° C. and aged for 2 hours to produce a total of 100 chip-type solid electrolytic capacitors. The capacitor element was subjected to a reflow test by passing it through a temperature range of 250 ° C. for 10 seconds, the leakage current was measured 1 minute after application of the rated voltage, and the average value was obtained for the measured value of 1 CV or less. The reflow defect rate was determined with a defective product of .01 CV or higher. These results are shown in Table 1.

Example 2:
In Example 1, chemical conversion treatment step II, the portion from the tip of the aluminum foil fixed to the metal guide to the first masking beyond the second masking was further immersed in an aqueous solution of ammonium adipate and a voltage of 15 V was applied. A solid electrolytic capacitor element was formed in the same manner as in Example 1 except that the entire peripheral portion including the entire second masking portion was formed.
Using the obtained solid electrolytic capacitor element, 100 chip-type solid electrolytic capacitors were produced in the same manner as in Example 1, and the leakage current characteristics were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 3:
100 chip-type solid electrolytic capacitors were produced in the same manner as in Example 1 except that the chemical conversion treatment step I was not performed. The results of measuring leakage current characteristics in the same manner as in Example 1 are shown in Table 1.

Example 4:
100 chip-type solid electrolytic capacitors were produced by the same method as in Example 2 except that the chemical conversion treatment step I was not performed. The results of measuring leakage current characteristics in the same manner as in Example 1 are shown in Table 1.

Comparative Example 1:
100 chip-type solid electrolytic capacitors were produced in exactly the same manner as in Example 1 except that the chemical conversion treatment step II was not performed. The results of measuring leakage current characteristics in the same manner as in Example 1 are shown in Table 1.

Examples 5-8:
In Examples 1 to 4, instead of an aqueous solution containing 25% by mass of ammonium persulfate, p-toluenesulfonic acid ferric iron 40% by mass ethyl alcohol solution (solution 2) and 3,4-ethylenedioxythiophene 20% by mass 100 capacitors were completed in the same manner as in Examples 1 to 4 except that 20% by mass of pyrrole ethyl alcohol (solution 1) was used instead of the isopropanol solution containing. The characteristics of these capacitor elements were evaluated in the same manner as in Examples 1 to 4, and the results are shown in Table 2.

Comparative Example 2:
In Comparative Example 1, instead of an aqueous solution containing 25% by mass of ammonium persulfate, it was replaced with a 40% by mass of ferric p-toluenesulfonic acid ethyl alcohol solution, and an isopropanol solution containing 20% by mass of 3,4-ethylenedioxythiophene. 100 capacitors were completed in the same manner as Comparative Example 1 except that 20% by mass of pyrrole ethyl alcohol was used. The characteristics of these capacitor elements were evaluated in the same manner as in Comparative Example 1, and the results are shown in Table 2.

  As shown in the above example, when the chemical conversion treatment is performed on the periphery after masking (second masking) according to the method of the present invention (Example), the characteristics are remarkably compared with the case where the chemical conversion treatment is not performed. It has been improved. In addition, when the chemical conversion treatment is performed on the area covering the entire masking (second masking), the characteristics superior to those obtained when the chemical conversion treatment is performed only on the area up to the lower edge of the masking (second masking) are shown. (In contrast to Examples 1, 3, 5 and 7, Examples 2, 4, 6 and 8 respectively). On the other hand, when the chemical conversion process I is not performed after the first masking and the chemical conversion process of the region including the periphery is performed only after the second masking (Examples 1, 2, 5, and 6), the second unexpectedly. There is no significant difference from the case of performing the chemical conversion treatment I and the chemical conversion treatment II before and after masking (examples 3, 4, 7, and 8 with respect to the examples 1, 2, 5, and 6, respectively), and the chemical conversion treatment I is omitted. It has been shown that an advantageous process can be employed.

  The method of the present invention realizes repair of damage to the dielectric layer by masking, and can be widely applied to the production of solid electrolytic capacitors having a masking layer on the dielectric layer.

It is sectional drawing which shows the basic structure of a solid electrolytic capacitor element. It is explanatory drawing which shows the relationship between the masking at the time of applying a prior art to a solid electrolytic capacitor element, and chemical conversion treatment. It is explanatory drawing which shows the outline of the one aspect | mode of the manufacturing method of the solid electrolytic capacitor element by this invention. It is explanatory drawing which shows the outline of another aspect of the manufacturing method of the solid electrolytic capacitor element by this invention. It is explanatory drawing which shows the outline of another aspect of the manufacturing method of the solid electrolytic capacitor element by this invention.

Explanation of symbols

1 Anode substrate 2 Dielectric oxide film (chemical conversion layer)
DESCRIPTION OF SYMBOLS 3 Masking 3a 1st masking 3b 2nd masking 4 Solid electrolyte layer 5 2nd chemical conversion treatment layer 6 2nd chemical conversion treatment layer (area | region between 1st masking-2nd masking)

Claims (17)

  Forming a mask on a part of the anode base material having a dielectric film on the surface so as to partition the surface, and forming a solid electrolyte layer in at least a part of the surface of the anode base material defined by the masking. A method for manufacturing a solid electrolytic capacitor element, comprising: performing a chemical conversion treatment on a region including a masking edge after the masking is formed.   A first masking is formed on a part of the anode base material having a dielectric film on the surface so as to partition the surface, and a solid electrolyte layer is formed on a part of the surface of the anode base material defined by the first masking. In the method of manufacturing a solid electrolytic capacitor element including the step of: forming a second mask so as to partition a region where a solid electrolyte layer is to be formed, and after forming the first and second masks, at least an edge of the second masking The manufacturing method of the solid electrolytic capacitor element characterized by including the process of performing a chemical conversion treatment to the area | region containing a part.   The manufacturing method of the solid electrolytic capacitor element of Claim 2 which performs a chemical conversion process to the area | region containing the edge part of a 1st masking after formation of a 1st masking.   4. The method for manufacturing a solid electrolytic capacitor element according to claim 2, wherein after the second masking is formed, a chemical conversion treatment is applied to a region including the entire second masking and the edge of the first masking. 5.   In a region between the first masking and the second masking, the chemical conversion treatment is performed on the region including the edge of the second masking, and then a solid electrolyte layer is formed in the region partitioned by the second masking. The manufacturing method of the solid electrolytic capacitor element in any one of Claims 2-4 including the process of cut | disconnecting.   The method for producing a solid electrolytic capacitor element according to claim 1, wherein masking is formed by applying a masking material solution.   The method for producing a solid electrolytic capacitor element according to claim 6, wherein the masking material solution is a solution that penetrates into the dielectric film and forms a masking layer on the penetration portion.   The method for producing a solid electrolytic capacitor element according to claim 7, wherein the masking material solution is a solution of a heat resistant resin or a precursor thereof.   9. The method for producing a solid electrolytic capacitor element according to claim 8, wherein the solution of the heat resistant resin or a precursor thereof is a low molecular weight polyimide solution or a polyamic acid solution that is solidified by heating.   The method for producing a solid electrolytic capacitor according to claim 9, wherein the masking material solution further contains silicone oil, a silane coupling agent, or polyimidesiloxane.   The method for producing a solid electrolytic capacitor element according to claim 1, wherein the anode base material is a valve metal having a porous layer on the surface.   The method of manufacturing a solid electrolytic capacitor element according to claim 11, wherein the metal material having a valve action is a material selected from aluminum, tantalum, niobium, titanium, zirconium, and alloys thereof.   The solid electrolyte according to claim 1, wherein the solid electrolyte is a polymer solid electrolyte containing at least one of a divalent group containing pyrrole, thiophene, aniline, and furan skeleton or a substituted derivative thereof as a repeating unit. Manufacturing method of electrolytic capacitor element.   The method for producing a solid electrolytic capacitor element according to claim 13, wherein the polymer solid electrolyte contains a polymer of 3,4-ethylenedioxythiophene.   The method for producing a solid electrolytic capacitor element according to claim 1, wherein the solid electrolyte further contains an aryl sulfonate dopant.   The solid electrolytic capacitor element manufactured by the manufacturing method of the solid electrolytic capacitor element in any one of Claims 1-15. A solid electrolytic capacitor comprising the solid electrolytic capacitor element according to claim 16.

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