JP5641151B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solid electrolytic capacitor and a method for producing the same, and more particularly to an improvement for preventing undesired penetration of a cathode raw material solution into an anode part in a solid electrolytic capacitor.

  A solid electrolytic capacitor that is of interest to the present invention is described, for example, in WO 2006/137482 republished publication (Patent Document 1). The solid electrolytic capacitor described in Patent Document 1 includes a valve metal base 1 as shown in FIG.

  Referring to FIG. 15, valve metal base 1 is made of, for example, an aluminum foil, and has a core portion 2 and a rough surface portion 3 formed along the surface thereof. The rough surface portion 3 is generated by etching the surface of the aluminum foil.

  Although not shown in FIG. 15, a cathode layer made of a conductive polymer layer, a carbon paste layer, and a silver paste layer is formed on the surface of the valve action metal substrate 1 through a dielectric film. The cathode portion of the solid electrolytic capacitor is provided by the portion where the above-described cathode layer is formed on the valve action metal substrate 1, while the anode portion is provided by the portion where the cathode layer is not formed on the valve action metal substrate 1. .

  Each of the conductive polymer layer, the carbon paste layer, and the silver paste layer serving as the cathode layer has a liquid or paste-like raw material solution (“cathode raw material solution”) on one end side to serve as the cathode portion of the valve action metal substrate 1. And may be collectively referred to as “)”. Therefore, it is necessary to prevent the cathode raw material solution from creeping up to the other end side to be the anode part along the valve action metal substrate 1, and to prevent a short circuit failure that may occur due to this creeping.

  In order to prevent the cathode raw material solution from creeping up as described above, a blocking member is provided at the boundary position between the cathode portion and the anode portion in the valve metal substrate. In the solid electrolytic capacitor described in Patent Document 1, as shown in FIG. 15, a concave portion 4 is formed in the rough surface portion 3 of the valve metal base 1, and a blocking member 5 is provided in a state embedded in the concave portion 4. Yes.

  In the technique described in Patent Document 1, the blocking member 5 is made of a resin that is soluble in a solvent. This resin is not only filled in the concave portion 4 but also inside the wall surface that defines the concave portion 4 in the rough surface portion 3. I try to infiltrate it. Therefore, the resin constituting the blocking member 5 suppresses the penetration of the cathode raw material solution through the rough surface portion 3 and, as a result, suppresses the cathode raw material solution from entering the anode portion by permeating through the rough surface portion 3. Works.

WO2006 / 137482 republication gazette

  However, in the device described in Patent Document 1, the cathode through the rough surface portion 3 is formed by allowing the resin to penetrate into the wall surface defining the concave portion 4 in the rough surface portion 3 by forming the blocking member 5 as described above. Although the penetration of the raw material solution is prevented, the resin penetration behavior tends to vary, and the resin is allowed to penetrate to a state where the penetration of the cathode raw material solution can be completely prevented with 100% reproducibility. It is difficult. Therefore, the technique described in Patent Document 1 has room for further improvement in terms of reliability or certainty of the effect of blocking the cathode raw material solution from entering the anode part.

  Accordingly, an object of the present invention is to provide a solid electrolytic capacitor and a method for manufacturing the same that can solve the above-described problems, that is, the reliability or certainty of the blocking effect by the blocking member is enhanced. is there.

  In order to solve the technical problem described above, a solid electrolytic capacitor according to the present invention includes a valve metal base having a penetrating portion and a blocking member fitted to the penetrating portion. The valve action metal substrate is divided into a cathode part and an anode part by a blocking member. The solid electrolytic capacitor according to the present invention includes a dielectric film formed on the surface of the cathode portion of the valve action metal substrate, and a cathode layer formed by applying a cathode raw material solution on the dielectric film. It has more. And the interruption | blocking member electrically conducts the cathode part and anode part of a valve action metal base | substrate, and the surface exposed from a penetration part has electrical insulation.

  In the blocking member, the surface exposed from the penetrating portion preferably has water repellency.

  Preferably, the blocking member is made of a valve metal member, and is electrically insulated by an oxide film formed on the surface thereof. Thereby, the heat resistance of the blocking member can be increased, and the heat treatment can be carried out without any problem in the manufacturing method described later.

  The blocking member is preferably made of the same metal as the valve action metal substrate. Thereby, the bondability between the valve metal base and the blocking member can be enhanced. This can also contribute to suppressing an increase in ESR of the solid electrolytic capacitor.

  The present invention is also directed to a method for manufacturing a solid electrolytic capacitor.

A method for producing a solid electrolytic capacitor according to the present invention includes:
(1) A valve action metal substrate preparation step of preparing a valve action metal substrate on which a dielectric film is formed;
(2) a penetrating part forming step of forming a penetrating part at a boundary position that divides the cathode part and the anode part in the valve action metal substrate;
(3) a blocking member fitting step for fitting the blocking member to the penetrating portion;
(4) a cathode layer forming step of forming a cathode layer using a cathode raw material solution on the dielectric film in a state where the formation region is limited by the blocking member;
(5) The blocking member fitted in the through portion is electrically connected to the cathode portion and the anode portion of the valve metal base, and the surface exposed from the through portion has electrical insulation. It is said.

  The time point when the dielectric film is formed on the valve action metal substrate prepared in the above (1) valve action metal substrate preparation step may be after the (3) blocking member fitting step. Moreover, you may implement simultaneously said (2) penetration part formation process and (3) interruption | blocking member fitting process. In other words, the blocking member itself may be pushed into the valve action metal base so as to be fitted into the through portion while forming the through portion.

  Preferably, the blocking member is made of a conductive material, and further includes a step of imparting electrical insulation to the surface exposed from the penetrating portion of the blocking member after the blocking member fitting step. Accordingly, it is possible to easily obtain a blocking member in which the cathode portion and the anode portion of the valve action metal base are electrically connected and the surface exposed from the penetrating portion has electrical insulation.

  In the above preferred embodiment, the blocking member is made of a valve metal member, and the step of imparting electrical insulation preferably includes a step of forming an oxide film on the surface of the valve metal member. The blocking member made of the valve action metal member has high heat resistance. Moreover, since the oxide film has electrical insulation, electrical insulation can be efficiently imparted to the exposed surface of the blocking member. When the surface of the oxide film is smooth, water repellency, that is, a property of repelling the cathode raw material solution can be provided.

  In order to form the above-mentioned oxide film, it is preferable that an anodizing process is applied and a heat treatment process is further implemented after the anodizing process. The heat treatment process is effective in strengthening the oxide film. As described above, when the heat resistance of the blocking member is increased, the heat treatment for strengthening the oxide film formed on the surface of the blocking member by anodizing treatment can be performed without any problem.

  The blocking member is preferably made of the same metal as the valve action metal substrate. As a result, the bonding property between the valve metal base and the blocking member can be enhanced, which can contribute to the suppression of ESR rise. Further, when the above-described anodizing treatment step is performed, the oxidation conditions are the same between the valve action metal substrate and the blocking member, so that an oxide film is formed on the surface of the blocking member and at the same time the valve action metal An oxide film, that is, a dielectric film can also be formed on the surface of the substrate.

  According to this invention, first, since the surface exposed from the penetrating portion of the blocking member has electrical insulation, even if the cathode raw material solution adheres, the short circuit that can occur due to electrical insulation is prevented. You can avoid inviting them.

  In addition, according to the present invention, since the blocking member is provided in a state of penetrating the valve action metal substrate, it is possible to reliably and reliably block the cathode raw material solution from entering the anode part. Therefore, also in this respect, it is possible to reliably prevent a short circuit failure.

  When the surface exposed from the penetrating portion of the blocking member has water repellency, adhesion of the cathode raw material solution to the blocking member is advantageously prevented by this water repellency.

1 is a cross-sectional view showing a solid electrolytic capacitor 10 according to an embodiment of the present invention. It is sectional drawing which expands and shows the part C of FIG. It is sectional drawing which expands and shows the part D of FIG. FIG. 1 is a diagram for explaining a first example of a manufacturing method of the solid electrolytic capacitor 10 shown in FIG. 1, and shows a mother metal foil 35 from which a plurality of valve action metal bases 14 can be taken out. FIG. It is a figure and (B) is sectional drawing which follows the line BB of (A). The state which formed the penetration part 17 in the mother metal foil 35 shown in FIG. 4 is shown, (A) is a front view, (B) is sectional drawing in alignment with line BB of (A). The state which fitted the interruption | blocking member 18 to the penetration part 17 of the mother metal foil 35 shown in FIG. 5 is shown, (A) is a front view, (B) is the cross section in alignment with line BB of (A). FIG. It is a front view which shows the state which stamped the mother metal foil 35 shown in FIG. 6 in the comb shape which has the several comb-tooth-shaped part 36 which should become the valve action metal base | substrate 14. FIG. It is a front view which shows the state which is implementing the anodizing process process with respect to the comb-shaped mother metal foil 35 shown in FIG. It is a front view which shows the state which is implementing the process of forming a conductive polymer layer with respect to the comb-shaped mother metal foil 35 after the anodizing process shown in FIG. It is a front view which shows the state which is implementing the process of forming a carbon paste layer with respect to the comb-shaped mother metal foil 35 after formation of the conductive polymer layer shown in FIG. It is a front view which shows the state which is implementing the process of forming a silver paste layer with respect to the comb-shaped mother metal foil 35 after formation of the carbon paste layer shown in FIG. FIG. 12 is a front view showing a comb-shaped mother metal foil 35 in which a cathode layer 27 is formed after the process shown in FIG. 11 is completed. By separating the plurality of comb-like portions 36 from the comb-shaped mother metal foil 35 shown in FIG. 12, the capacitor unit 11 composed of the plurality of valve metal substrates 14 provided with the cathode layer 27 and the blocking member 18 was taken out. It is a front view which shows a state. FIG. 7 is a diagram for explaining a second example of the method for manufacturing the solid electrolytic capacitor 10 shown in FIG. 1 and corresponds to FIG. 5B or FIG. 6B. It is sectional drawing which expands and shows the valve action metal base | substrate 1 described in patent document 1. FIG.

  A solid electrolytic capacitor 10 according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the solid electrolytic capacitor 10 includes a laminated body 13 in which three capacitor units 11 are stacked and joined together by a bonding material 12. Each of the three capacitor units 11 has a common configuration.

  Each capacitor unit 11 includes a valve metal base 14. The valve metal base 14 is made of, for example, an aluminum foil, and has a surface roughened by performing an etching process, thereby having a core portion 15 and a rough surface portion 16 formed along the surface. . The valve action metal base 14 is provided with a through portion 17 penetrating in the thickness direction.

  A blocking member 18 is fitted into the through portion 17. The blocking member 18 is fixed to the valve metal base 14 by welding, for example. The valve metal base 14 is divided into a cathode portion 19 and an anode portion 20 by the blocking member 18.

  As is well shown in FIG. 3, the blocking member 18 has conductivity at a portion in contact with the valve metal base 14, and electrically connects the cathode portion 19 and the anode portion 20 of the valve metal base 14. Conducted to. Moreover, the surfaces 21-23 exposed from the penetration part 17 in the interruption | blocking member 18 have electrical insulation. As an example, the blocking member 18 is made of, for example, an aluminum foil, and the above-described electrical insulation is provided by an oxide film 25 such as an aluminum oxide film formed on the surface thereof. Instead of the oxide film 25, a film made of an electrically insulating resin may be formed. Further, when the surface of the oxide film 25 is smooth, water repellency is further provided.

  The above-described aluminum foil as an example of the material constituting the blocking member 18 is a valve metal member, and when the valve metal base 14 is made of an aluminum foil, the blocking member 18 and the valve metal base 14 are of the same type. It will be composed of metal. When such a configuration is adopted, the heat resistance of the blocking member 18 can be increased, and in the manufacturing method described later, the heat treatment can be carried out without any problem, and the blocking member 18 and the valve metal substrate are used. 14 can be improved, thereby contributing to suppression of ESR rise.

  A dielectric film 26 (shown by a thick line in FIG. 1) is formed on the surface of the cathode portion 19 of the valve metal base 14. The dielectric film 26 is formed, for example, by oxidizing the surface of the valve action metal substrate 14.

  A cathode layer 27 is formed on the dielectric film 26. As shown in FIG. 2, the cathode layer 27 includes a conductive polymer layer 28, a carbon paste layer 29 thereon, and a silver paste layer 30 thereon. These layers 25 to 27 are formed by applying a corresponding raw material solution, that is, a cathode raw material solution, as will be described in detail later. Here, since the blocking member 18 is provided so as to penetrate the valve metal base 14, the penetration of the cathode raw material solution through the rough surface portion 16 is completely blocked, and the negative electrode raw material solution passes through the rough surface portion 16 and the anode portion 20. Can be prevented from entering.

  The three valve action metal substrates 14 provided with the blocking member 15 and the cathode layer 27 as described above constitute the capacitor unit 11, respectively. These three capacitor units 11 are stacked and bonded to each other by the bonding material 12. The laminated body 13 is comprised by joining.

  A cathode external terminal 31 is connected to the cathode portion 20 in the laminate 13, more specifically, to the silver paste layer 30 in the cathode layer 27. On the other hand, in the anode part 20 in the laminated body 13, each end part of the three valve action metal base | substrates 14 is bent so that it may gather in one place. An anode external terminal 32 is connected to the end of the valve action metal base 14 on the anode 20 side. In addition, an exterior resin 33 made of, for example, an epoxy resin (the outline of which is shown by an imaginary line in FIG. 1) is molded so as to cover the laminate 13.

  Next, a method for manufacturing the above-described solid electrolytic capacitor 10 will be described. 4 to 13 show a first example of the manufacturing method. 4 to 13, elements corresponding to those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

  First, as shown in FIG. 4, a mother metal foil 35 is prepared. By cutting the mother metal foil 35 later, the plurality of valve action metal substrates 14 can be taken out. The mother metal foil 35 is made of, for example, an aluminum foil having a thickness of 100 μm, and as described above, the surface is roughened by performing an etching process, thereby forming the core portion 15 and the surface thereof. And a rough surface portion 16. Further, the surface of the mother metal foil 35 is oxidized, whereby a dielectric film 26 (see FIGS. 1 to 3) made of, for example, aluminum oxide is formed.

  Next, as shown in FIG. 5, a plurality of through portions 17 are formed in part of the mother metal foil 35. The penetrating part 17 is located at the boundary between the cathode part 19 and the anode part 20 in the valve metal base 14 taken out from the mother metal foil 35.

  Next, as shown in FIG. 6, the blocking member 18 is prepared, and the blocking member 18 is fixed to the mother metal foil 35 in a state where the blocking member 18 is fitted to the through portion 17. As the blocking member 18, an aluminum foil having a smooth surface (not etched) is used. Further, in order to fix the blocking member 18 to the mother metal foil 35, for example, welding is applied.

  When the blocking member 18 and the mother metal foil 35 are made of the same metal as in this embodiment, the bondability between the blocking member 18 and the mother metal foil 35 can be improved. Therefore, the bondability between the valve action metal substrate 14 and the blocking member 18 can be improved, and therefore, the increase in ESR of the solid electrolytic capacitor 10 can be suppressed.

  Next, as shown in FIG. 7, the mother metal foil 35 is punched into a comb shape having a plurality of comb-like portions 36 to be the valve metal base 14. The punched-out blocking member 18 is located in the comb-shaped portion 36. As a result of the punching process, a cut surface 37 on which no dielectric film (oxide film) is formed appears on the mother metal foil 35.

  Next, as shown in FIG. 8, an anodic oxidation process is performed. That is, the electrolytic solution 39 is accommodated in the electrolytic bath 38, the comb-like portion 36 is immersed in the electrolytic solution 39 to the extent that the blocking member 18 is immersed, and the cathode 40 is disposed. The blocking member 18 is anodized while being connected to the anode side through the comb-shaped mother metal foil 35. As a result of the anodizing treatment, an oxide film 25 is formed on the surfaces 21 to 23 of the blocking member 18 as shown in FIG.

  The oxide film 25 has electrical insulating properties, and particularly has good water repellency with respect to the cathode raw material solution when the surface is smooth. Therefore, it is possible to prevent the cathode raw material solution to be the cathode layer 27 from adhering to the surfaces 21 to 23 of the blocking member 18 in the step of forming the cathode layer 27 described later. Even if the cathode raw material solution crawls up to the surface 21 on the cathode portion 19 side of the blocking member 18 and further to the surface 22 following the surface 21, the worst electrical short circuit can be avoided.

  Since the cathode raw material solution hardly reaches the surface 23 of the blocking member 18 on the anode portion 20 side, it is sufficient that the oxide film 25 is formed only on the surfaces 21 and 22. Further, the oxide film 25 is not formed on the entire surface 22 of the surface 22, but may be formed only on a part on the surface 21 side or may not be formed.

  The region where the oxide film 25 is formed as described above can be changed by adjusting the position of the electrolytic solution 29 in the anodizing step shown in FIG.

  Further, when the mother metal foil 35 and the blocking member 18 are made of the same kind of metal, both have the same oxidation conditions. Therefore, as a result of the above-described anodizing treatment, the comb-shaped mother metal foil 35 that appears in the punching process described above. A dielectric film (oxide film) is also formed on the cut surface. As can be seen from this, the dielectric film 26 (see FIGS. 1 to 3) is not formed in advance on the surface of the mother metal foil 35 before the punching process, but in this anodizing process, the comb-shaped mother is used. The dielectric film 26 may be formed on the surface of the metal foil 35.

  As an example, when the mother metal foil 35 and the blocking member 18 are made of aluminum foil, a voltage of 3.5 V is applied between the mother metal foil 35 and the cathode 40 while using an ammonium adipate aqueous solution as the electrolyte 39. Thus, aluminum oxide is formed on each surface of the mother metal foil 35 and the blocking member 18 in the electrolytic solution 39.

  After finishing the anodizing treatment step, a heat treatment step is preferably performed. In the heat treatment step, for example, conditions of 300 ° C. and 30 minutes are applied. The heat treatment is effective to reinforce the anodized film, more specifically, to reduce defective portions of the anodized film. Reduction of the defective portion of the anodized film contributes to reduction of leakage current of the solid electrolytic capacitor 10. Such heat treatment condition setting is limited by the heat resistance of the heat treatment target component, but as a material constituting the blocking member 18, such as aluminum having higher heat resistance than conventionally used polyimide resin. By using a valve metal, the degree of freedom in setting heat treatment conditions can be increased.

  Next, as shown in FIG. 9, the comb-like portion 36 of the mother metal foil 35 is immersed in a conductive polymer raw material solution 42 accommodated in a conductive polymer solution tank 41. At this time, the application region of the conductive polymer raw material solution 42 is limited by the blocking member 18. Thereafter, the comb-like portion 36 is pulled up from the conductive polymer raw material solution 42 and dried as necessary. In this way, the conductive polymer layer 28 (see FIG. 2) is formed on the comb-like portion 36.

  A specific example of the process for forming the conductive polymer layer will be described below. As described above, the mother metal foil 35 and the blocking member 18 made of aluminum foil on which aluminum oxide is formed are connected to the conductive polymer raw material solution 42. After immersing in an isopropanol solution containing 3,4-ethylenedioxythiophene as a solution and then immersing in a mixed solution of ammonium persulfate and sodium anthraquinone disulfonate 20 times, polyethylene oxide A conductive polymer layer made of oxythiophene is formed.

  Next, as shown in FIG. 10, the comb-like portion 36 of the mother metal foil 35 on which the conductive polymer layer is formed is immersed in the carbon paste 44 accommodated in the carbon paste tank 43. At this time, the application region of the carbon paste 44 is limited by the blocking member 18. Thereafter, the comb-like portion 36 is pulled up from the carbon paste 44 and dried as necessary. In this way, the carbon paste layer 29 (see FIG. 2) is formed on the conductive polymer layer 28.

  Next, as shown in FIG. 11, the comb-like portion 36 of the mother metal foil 35 on which the conductive polymer layer and the carbon paste layer are formed is immersed in the silver paste 46 accommodated in the silver paste tank 45. The At this time, the application region of the silver paste 46 is limited by the blocking member 18. Thereafter, the comb-like portion 36 is pulled up from the silver paste 46 and dried as necessary. In this way, a silver paste layer 30 (see FIG. 2) is formed on the carbon paste layer 29.

  FIG. 12 shows the comb-shaped mother metal foil 35 pulled up from the silver paste 46 as described above. On the comb-like portion 36 of the mother metal foil 35, the cathode layer 27 composed of the above-described conductive polymer layer, carbon paste layer, and silver paste layer is formed in a state limited by the blocking member 18.

  Next, as shown in FIG. 13, the plurality of comb-like portions 36 are cut from the comb-shaped mother metal foil 35, and thereby the plurality of capacitor units 11 each including the valve metal base 14 are taken out.

  Referring again to FIG. 1, next, a step of stacking the plurality of valve action metal substrates 14 on which the cathode layer 27 is formed, that is, the plurality of capacitor units 11, through the bonding material 12 is performed. Here, it is preferable to use a low-stress resin as the bonding material 12. Note that the bonding material 12 may be conductive or non-conductive.

  After completing the stacking as described above, a heat treatment or the like for curing the bonding material 12 is performed, whereby the laminate 13 is obtained.

  Thereafter, as shown in FIG. 1, the cathode external terminal 31 is joined so as to be electrically connected to the cathode layer 27 in the laminate 13, while the anode portion 20 side of the valve metal substrate 14 in the laminate 13. The anode external terminal 32 is joined so as to be electrically connected to the end of the electrode.

  Then, the exterior resin 33 is molded, and the solid electrolytic capacitor 10 is completed.

  FIG. 14 shows a second example of the manufacturing method of the solid electrolytic capacitor 10 shown in FIG. In the first example described above, as shown in FIG. 5, the penetrating portion 17 is formed in advance in the mother metal foil 35, and then the blocking member 18 is fitted into the penetrating portion 17. On the other hand, in the second example shown in FIG. 14, the blocking member 18 is formed on the mother metal foil 35 while forming a penetrating portion by pressing toward the mother metal foil 35 as indicated by an arrow 48. A state as shown in FIG. Thereafter, the blocking member 18 is joined to the mother metal foil 35.

  Other steps in the second example are substantially the same as those in the first example.

DESCRIPTION OF SYMBOLS 10 Solid electrolytic capacitor 14 Valve action metal base | substrate 15 Core part 16 Rough surface part 17 Penetration part 18 Blocking member 19 Cathode part 20 Anode part 21-23 Surface 25 Oxide film 26 Dielectric film 27 Cathode layer 28 Conductive polymer layer 29 Carbon paste Layer 30 Silver paste layer 39 Electrolytic solution 42 Conductive polymer raw material solution 44 Carbon paste 46 Silver paste

Claims (9)

A valve-acting metal substrate having a penetrating portion;
A blocking member fitted to the penetrating portion,
The valve metal base is divided into a cathode part and an anode part by the blocking member,
A dielectric film formed on the surface of the cathode portion of the valve metal substrate;
A cathode layer formed by applying a cathode raw material solution on the dielectric film;
A solid electrolytic capacitor,
The blocking member electrically connects the cathode part and the anode part of the valve metal base, and the surface exposed from the through part has electrical insulation. Electrolytic capacitor.   The solid electrolytic capacitor according to claim 1, wherein a surface of the blocking member exposed from the penetrating portion has water repellency.   3. The solid electrolytic capacitor according to claim 1, wherein the blocking member is made of a valve metal member, and the electrical insulation is given by an oxide film formed on a surface thereof.   4. The solid electrolytic capacitor according to claim 1, wherein the blocking member is made of the same metal as the valve action metal base. 5. Preparing a valve action metal substrate on which a dielectric film is formed, and a valve action metal substrate preparation step;
A penetration part forming step of forming a penetration part at a boundary position separating the cathode part and the anode part in the valve action metal substrate;
A blocking member fitting step for fitting a blocking member to the penetrating portion;
A cathode layer forming step of forming a cathode layer using a cathode raw material solution on the dielectric film in a state where a formation region is limited by the blocking member;
The blocking member fitted in the through portion electrically connects the cathode portion and the anode portion of the valve metal base, and a surface exposed from the through portion has electrical insulation. ,
A method for producing a solid electrolytic capacitor.   6. The solid electrolysis according to claim 5, wherein the blocking member is made of a conductive material, and further includes a step of imparting the electrical insulation to a surface exposed from the penetrating portion of the blocking member after the blocking member fitting step. Capacitor manufacturing method.   The method for producing a solid electrolytic capacitor according to claim 6, wherein the blocking member is made of a valve metal member, and the step of imparting electrical insulation includes a step of forming an oxide film on a surface of the valve metal member. .   The method for producing a solid electrolytic capacitor according to claim 7, wherein the step of forming the oxide film includes an anodizing treatment step, and further comprising a heat treatment step after the anodizing treatment step.   The method for manufacturing a solid electrolytic capacitor according to claim 5, wherein the blocking member is made of the same metal as the valve action metal base.

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