JP2007165700A - Solid electrolytic capacitor and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a solid electrolytic capacitor that reduces leakage current defects of the surface-mounted solid electrolytic capacitor, by repairing defects during the manufacture of the solid electrolytic capacitor, and removing defectives. <P>SOLUTION: The manufacturing method for the solid electrolytic capacitor includes the steps of forming an anode body of metal having a valve operation, forming a dielectric film at least in a portion of its surface through a conversion treatment, forming a conductive polymer layer and a conductive paste layer as a cathode body, in this order, and sealing the capacitor element obtained with resin. The capacitor element is heated above 180°C prior to resin sealing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid electrolytic capacitor and a manufacturing method thereof, and more particularly to a solid electrolytic capacitor having improved electrical characteristics and a manufacturing method thereof.

  The basic element of a solid electrolytic capacitor is generally formed by forming a dielectric oxide film layer on an anode substrate made of a metal foil that has been etched and having a large specific surface area, and a solid semiconductor layer (hereinafter referred to as a solid electrolyte) as an electrode facing the outside. And a conductive layer such as a conductive paste is preferably formed. Then, such an element is used alone or in a laminated manner to join lead wires, and the whole is completely sealed with an epoxy resin or the like, and is widely used as a capacitor part in electric products.

  As a method for producing such a solid electrolytic capacitor, after covering a capacitor element using a conductive polymer as a solid electrolyte with a thermosetting resin, the resin is heated at a temperature higher than the glass transition point of the thermosetting resin. Post-cure process for post-cure treatment of the exterior, moisture-absorption process for allowing the capacitor element to absorb moisture by keeping it constant temperature / humidity for a certain period of time, and aging process process for applying voltage at high temperature to perform aging process And a method in which a drying process for drying moisture absorbed by the capacitor element is sequentially provided (Patent Document 1: Japanese Patent Laid-Open No. 9-246114), after the resin sheathing, a rated voltage of 1.5-2. Aging process by applying a voltage of 0 times (Patent Document 2: Japanese Patent Laid-Open No. 2000-331889), before or after resin exterior, ambient temperature 20 to 90 ° C. How to aging in an atmosphere of RH humidity 50% to 95% (Patent Document 3: JP 2005-079334 publication) or the like is disclosed. In any case, the leakage current is reduced, but the leakage current characteristics of the solid electrolytic capacitors produced by these manufacturing methods are insufficient. In particular, a high voltage capacitor having a rated voltage of 10 V or higher is required to have high reliability because it is used at a high voltage.

JP-A-9-246114 JP 2000-331889 A JP-A-2005-079334

As a cause of the leakage current, defects due to mechanical and chemical stress in various processes at the time of manufacturing the capacitor can be considered. Therefore, in order to manufacture a highly reliable capacitor, it is necessary to repair these defects and remove defective products that cannot withstand a high temperature / humidity environment.
An object of the present invention is to provide a method of manufacturing a solid electrolytic capacitor that repairs such defects and removes defective products and reduces the leakage current of the surface-mounted solid electrolytic capacitor.

  In order to solve the above-mentioned problems, the present inventors use a metal having a valve action as an anode body, form a dielectric film by chemical conversion treatment on at least a part of the surface, and form a conductive polymer layer as a cathode body, In a method of manufacturing a solid electrolytic capacitor including a step of sequentially forming a conductive paste layer and resin-sealing the obtained capacitor element, after sealing the capacitor element by heating at 180 ° C. or higher before resin sealing A step of performing a humidification treatment in an atmosphere having a relative humidity of 60% or higher by performing a curing treatment of the sealing resin at a temperature lower than the glass transition point of the sealing resin, and a rated voltage in an atmosphere of 50 ° C. or higher. A step of aging by applying a voltage of 1 to 5 times the above, a step of heating at 180 ° C. or higher, a step of applying a voltage of 0.5 to 4 times the rated voltage at least once in an atmosphere of 0 ° C. or higher, Leakage current failure is reduced by applying one or more steps of applying a voltage 1.1 to 4 times the rated voltage and removing those with a leakage current of 1 CV or more, or a combination of these steps. It was confirmed that it was possible to complete the present invention.

That is, this invention relates to the manufacturing method and solid electrolytic capacitor of a solid electrolytic capacitor shown below.
1. Capacitor element obtained by using a metal having a valve action as an anode body, forming a dielectric film by chemical conversion treatment on at least a part of the surface, and sequentially forming a conductive polymer layer and a conductive paste layer as a cathode body A process for producing a solid electrolytic capacitor comprising a step of resin-sealing a capacitor element, wherein the capacitor element is heated at 180 ° C. or higher before resin-sealing.
2. 2. The method for producing a solid electrolytic capacitor as described in 1 above, which comprises a step of curing the resin at a temperature not higher than the glass transition point of the resin after resin sealing.
3. 3. The method for producing a solid electrolytic capacitor as described in 1 or 2 above, comprising a step of performing a humidification treatment in an atmosphere having a relative humidity of 60% or more after the resin curing treatment.
4). 4. The method for producing a solid electrolytic capacitor according to any one of 1 to 3, further comprising a step of aging by applying a voltage 1 to 5 times the rated voltage in an atmosphere of 50 ° C. or higher after the resin curing treatment.
5. 5. The method for producing a solid electrolytic capacitor as described in 4 above, comprising a step of performing a heat treatment at 180 ° C. or higher after the aging.
6). 6. The solid electrolytic capacitor according to 5 above, comprising a step of re-aging by applying a voltage of 0.5 to 5 times the rated voltage at least once in an atmosphere at 0 ° C. or higher after the heat treatment at 180 ° C. or higher. Production method.
7). 7. The method for producing a solid electrolytic capacitor according to any one of 1 to 6, further comprising a step of applying a voltage 1 to 5 times a rated voltage after the re-aging to remove a leakage current of 1 CV or more.
8). The solid electrolytic capacitor manufactured by the manufacturing method of the solid electrolytic capacitor in any one of said 1-7.

  According to the preferred embodiment of the present invention, it is possible to repair defects and remove defective products that occur during the production of the solid electrolytic capacitor, and to reduce the leakage current failure of the surface mounted solid electrolytic capacitor.

Hereafter, the manufacturing method of the solid electrolytic capacitor of the preferable embodiment in this invention is demonstrated in detail.
In the present invention, a metal having a valve action is used as an anode body, a dielectric film is formed on at least a part of the surface by chemical conversion treatment, and a conductive polymer layer and a conductive paste layer are sequentially formed as a cathode body. In the method for producing a solid electrolytic capacitor including the step of resin-sealing the obtained capacitor element, the capacitor element is heated at 180 ° C. or higher before resin sealing.

  By heating the capacitor element at 180 ° C. or higher before resin sealing, physical deformation such as expansion of the laminated element is reduced even if reflow at 200 ° C. or higher after resin sealing is performed, and the manufactured capacitor The leakage current characteristic of the is improved. The upper limit of the heating temperature is preferably about 250 ° C. Even at higher temperatures, there is no noticeable improvement in effect. Although it depends on required electrical characteristics, heating in the range of 190 to 220 ° C. is usually more preferable.

  The heat treatment may be performed before or after the capacitor elements are stacked. In the case of a winding type, it may be performed before winding and after winding. The heating time is preferably about 30 seconds to 10 hours, more preferably about 1 minute to 2 hours. However, the heating time may be shorter as the heating temperature is higher. For example, the heating may be performed at 250 ° C. for several tens of seconds.

  As the resin used at the time of sealing the capacitor element, a general thermosetting resin is used, and an epoxy resin is preferably used because water resistance, chemical resistance, and electrical insulation are particularly high.

  In this invention, after resin sealing, resin hardening is performed at the temperature below the glass transition point of the sealing resin. For example, when an epoxy resin having a glass transition point of about 160 to 170 ° C. is used as the sealing resin, the resin is cured by heating at 145 to 155 ° C., for example. The heating time may be a time required for curing.

  In the present invention, after the resin curing treatment, it is preferable to perform the humidification treatment by leaving the capacitor in an atmosphere having a relative humidity of 60% or more. The temperature is preferably 50 to 95 ° C. Higher humidity and higher temperature are preferable because they can be processed in a shorter time.

  In addition, aging is performed by applying a voltage 1 to 5 times the rated voltage in order to repair the deterioration of the thermal and / or physical dielectric layer during electrode layer formation or exterior. Aging is preferably performed after the humidification treatment. By applying a high voltage, potential defective products can be removed more reliably, but even if a high voltage of 5 times or more is applied, no significant improvement in effect is observed. A voltage application of 1.25 to 4 times the rated voltage is more preferable. For example, a voltage application of 50 V can be performed at a rated voltage of 12.5 V. If heating is performed at the same time, the aging time can be shortened. As heating conditions, 100-140 degreeC is preferable. As the aging is performed at a higher temperature, the withstand voltage of the capacitor is lowered, and even at the same voltage, a capacitor with a low withstand voltage fails due to aging, so that the effect of removing defective products is enhanced.

  After aging, heat treatment may be further performed at 180 ° C. or higher. Thereafter, re-aging may be performed as desired for the purpose of further repairing the withstand voltage test and degradation of the thermal and / or physical dielectric layer during electrode layer formation and exterior. As conditions, it is preferable to repeat the voltage application at 0.5 to 5 times, preferably 0.5 to 4 times the rated voltage at 20 ° C. or more once or more. Although the withstand voltage of the capacitor is lowered due to the above-described heating at 180 ° C. and a failure occurs, the leakage current increases rapidly, but those with a high withstand voltage are repaired by this aging. By repeating the operation one or more times, failure during ON / OFF during actual use can be avoided.

  Here, the heat treatment at 180 ° C. or more and 3 seconds or more may be repeated a plurality of times. By performing this heating, potential defective products can be removed.

  A capacitor manufactured by the above procedure is selected for defective products by measuring leakage current. The leakage current is measured by applying a voltage 1 to 5 times, preferably 1.1 to 4 times the rated voltage. A leakage current of 1 CV or more, preferably 0.5 CV or more, more preferably 0.04 CV or more is removed as a defective product. Here, C represents a rated capacity, and V represents a rated voltage. By applying a voltage higher than the rated voltage, a more reliable mounted product can be provided.

The dielectric coating on the surface of the anode substrate used in the present invention is usually formed by subjecting a metal porous molded body having a valve action to chemical conversion treatment or the like.
Examples of the metal having a valve action that can be used in the present invention include simple metals such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, silicon, and alloys thereof. The porous form may be any form as long as it is a form of a porous molded body such as an etched product of rolled foil or a fine powder sintered body.

  As the anode base material, porous sintered bodies of these metals, plates (including ribbons, foils, etc.) surface-treated by etching, etc., wires, etc. can be used, but preferably in the form of a flat plate or foil. is there. Furthermore, a known method can be used as a method of forming a dielectric oxide film on the surface of the porous metal body. For example, when an aluminum foil is used, an oxide film can be formed by anodizing in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or a sodium salt or an ammonium salt thereof. Moreover, when using the sintered compact of a tantalum powder, it can anodize in phosphoric acid aqueous solution and can form an oxide film in a sintered compact.

  For example, the thickness of the valve action metal foil varies depending on the purpose of use, but a foil having a thickness of about 40 to 300 μm is used. In order to obtain a thin solid electrolytic capacitor, for example, an aluminum foil having a thickness of 80 to 250 μm is preferably used, and the maximum height of the element provided with the solid electrolytic capacitor is preferably 250 μm or less. Although the size and shape of the metal 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, more preferably about 2 to 15 mm in width and about 2 in length. ~ 25 mm.

  Chemical conversion conditions such as chemical conversion liquid and chemical conversion voltage used for chemical conversion are confirmed in advance by experiments and set to appropriate values according to the capacity, withstand voltage, etc. required for the solid electrolytic capacitor to be produced. In addition, in the chemical conversion treatment, the chemical conversion liquid is prevented from spreading to the portion that becomes the anode of the solid electrolytic capacitor, and the insulation from the solid electrolyte (cathode portion) formed in the solid electrolyte layer forming step is ensured. Generally, masking is provided.

  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, etc. can be used, but the material is not limited. . Specific examples include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), low molecular weight polyimides and their Examples thereof include derivatives and precursors thereof, and low molecular weight polyimides, polyethersulfones, fluororesins and their precursors are particularly preferable.

  According to the present invention, an aluminum foil having a dielectric oxide film is impregnated, for example, in an isopropyl alcohol (IPA) solution of 3,4-ethylenedioxythiophene (EDT), as shown in the following examples. After substantially drying IPA to remove IPA, impregnation with about 20% by mass of an oxidizing agent (ammonium persulfate) aqueous solution, followed by heating at about 40 ° C. for 10 minutes, and by repeating this step, poly (3 , 4-ethylenedioxythiophene) polymer can be obtained.

  The conductive polymer forming the solid electrolyte used in the present invention is a polymer of an organic polymer monomer having a π-electron conjugated structure, and the degree of polymerization is 2 or more and 2000 or less, more preferably 3 or more and 1000 or less, and still more preferably 5 It is 200 or less. As specific examples, a conductive polymer containing a structure represented by a compound having a thiophene skeleton, a compound having a polycyclic sulfide skeleton, a compound having a pyrrole skeleton, a compound having a furan skeleton, a compound having an aniline skeleton, or the like as a repeating unit. Is mentioned.

  Examples of the monomer having a thiophene skeleton include 3-methylthiophene, 3-ethyloffene, 3-propylthiophene, 3-butylthiophene, 3-pentylthiophene, 3-hexylthiophene, 3-heptylthiophene, 3-octylthiophene, 3-nonylthiophene, 3-decylthiophene, 3-fluorothiophene, 3-chlorothiophene, 3-bromothiophene, 3-cyanothiophene, 3,4-dimethylthiophene, 3,4-diethylthiophene, 3,4-butylenethiophene , Derivatives of 3,4-methylenedioxythiophene, 3,4-ethylenedioxythiophene, and the like. These compounds can be prepared by commercially available compounds or by known methods (for example, Synthetic Metals, 1986, Vol. 15, p. 169).

  Specific examples of the monomer having a polycyclic sulfide skeleton include compounds having a 1,3-dihydropolycyclic sulfide (also known as 1,3-dihydrobenzo [c] thiophene) skeleton, 1,3-dihydronaphtho [2,3 -C] A compound having a thiophene skeleton can be used. Furthermore, a compound having a 1,3-dihydroanthra [2,3-c] thiophene skeleton and a compound having a 1,3-dihydronaphthaseno [2,3-c] thiophene skeleton can be given. These can be prepared by a known method, for example, the method described in JP-A-8-3156.

  A compound having a 1,3-dihydronaphtho [1,2-c] thiophene skeleton is a 1,3-dihydrophenanthra [2,3-c] thiophene derivative or 1,3-dihydrotriphenylo [2]. , 3-c] thiophene skeleton, 1,3-dihydrobenzo [a] anthraceno [7,8-c] thiophene derivatives and the like can also be used.

  A compound optionally containing nitrogen or N-oxide in the condensed ring can also be used, for example, 1,3-dihydrothieno [3,4-b] quinoxaline, 1,3-dihydrothieno [3,4-b] quinoxaline- 4-oxide, 1,3-dihydrothieno [3,4-b] quinoxaline-4,9-dioxide and the like can be mentioned.

  Examples of the monomer having a pyrrole skeleton include 3-methylpyrrole, 3-ethylpyrrole, 3-propylpyrrole, 3-butylpyrrole, 3-pentylpyrrole, 3-hexylpyrrole, 3-heptylpyrrole, 3-octylpyrrole, 3-nonylpyrrole, 3-decylpyrrole, 3-fluoropyrrole, 3-chloropyrrole, 3-bromopyrrole, 3-cyanopyrrole, 3,4-dimethylpyrrole, 3,4-diethylpyrrole, 3,4-butylenepyrrole , Derivatives of 3,4-methylenedioxypyrrole, 3,4-ethylenedioxypyrrole, and the like. These compounds can be prepared commercially or by known methods.

  Examples of the monomer having a furan skeleton include 3-methylfuran, 3-ethylfuran, 3-propylfuran, 3-butylfuran, 3-pentylfuran, 3-hexylfuran, 3-heptylfuran, 3-octylfuran, 3-nonylfuran, 3-decylfuran, 3-fluorofuran, 3-chlorofuran, 3-bromofuran, 3-cyanofuran, 3,4-dimethylfuran, 3,4-diethylfuran, 3,4-butylenefuran, 3,4 -Derivatives such as methylenedioxyfuran and 3,4-ethylenedioxyfuran can be mentioned. These compounds can be prepared commercially or by known methods.

  Examples of the monomer having an aniline skeleton include 2-methylaniline, 2-ethylaniline, 2-propylaniline, 2-butylaniline, 2-pentylaniline, 2-hexylaniline, 2-heptylaniline, 2-octylaniline, 2-nonylaniline, 2-decylaniline, 2-fluoroaniline, 2-chloroaniline, 2-bromoaniline, 2-cyanoaniline, 2,5-dimethylaniline, 2,5-diethylaniline, 2,3-butyleneaniline , Derivatives of 2,3-methylenedioxyaniline, 2,3-ethylenedioxyaniline, and the like. These compounds can be prepared commercially or by known methods.

Among these, compounds having a thiophene skeleton or a polycyclic sulfide skeleton are preferable, and 3,4-ethylenedioxythiophene (EDT) and 1,3-dihydroisothianaphthene are particularly preferable.
There is no restriction | limiting in particular in the polymerization conditions etc. of the compound selected from the said compound group, It can implement easily, after confirming preferable conditions beforehand by simple experiment.

In addition, a compound selected from the above monomer group may be used in combination to form a solid electrolyte as a copolymer. The composition ratio of the polymerizable monomer at that time depends on the polymerization conditions and the like, and the preferred composition ratio and polymerization conditions can be confirmed by a simple test.
For example, a method in which the EDT monomer and the oxidizing agent are preferably applied in the form of a solution and applied separately or together to the oxide film layer of the metal foil can be used (Patent No. 3040113, US Pat. 6229689).

  3,4-ethylenedioxythiophene (EDT) preferably used in the present invention dissolves well in the above monohydric alcohol, but is not well-suited with water, so when brought into contact with a high concentration aqueous oxidant solution, In the EDT, polymerization proceeds satisfactorily at the interface, and a conductive polymer solid electrolyte layer having a fibril structure or a lamellar (thin layered) structure is formed.

  In the production method of the present invention, as a solvent for washing after formation of the solid electrolyte, for example, ethers such as tetrahydrofuran (THF), dioxane, and diethyl ether; ketones such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, benzonitrile, N -Aprotic polar solvents such as methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO); esters such as ethyl acetate and butyl acetate; non-aromatic chlorinated solvents such as chloroform and methylene chloride; nitromethane, nitroethane, and nitrobenzene Nitro compounds such as: alcohols such as methanol, ethanol, propanol, etc .; organic acids such as formic acid, acetic acid, propionic acid; acid anhydrides of the organic acids (eg, acetic anhydride, etc.) or water or mixed solvents thereof Can do. Preferably, water, alcohols or ketones or a mixed system thereof is desirable.

  The electrical conductivity of the solid electrolyte thus produced is in the range of about 0.1 to about 200 S / cm, preferably about 1 to about 150 S / cm, more preferably about 10 to about 100 S / cm. Range.

  On the conductive polymer composition layer thus formed, it is preferable to provide a conductor layer in order to improve electrical contact with the cathode lead terminal. The conductor layer is formed by, for example, a conductive paste, plating, vapor deposition, or a conductive resin film.

  The solid electrolytic capacitor element thus obtained is usually made into a capacitor product for various applications by connecting lead terminals and applying an exterior such as a resin mold, a resin case, a metal outer case, or a resin dipping.

  Further, in the present invention, after forming the conductor layer, these are bonded and laminated with a conductive paste or the like, and a lead terminal is connected to the obtained laminate and sealed to form a multilayer solid electrolytic capacitor. Alternatively, a known method may be adopted to form a wound type solid electrolytic capacitor.

  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:
An aluminum conversion foil (thickness: about 100 μm) having a porous surface was cut out in a minor axis direction of 3 mm × a major axis direction of 10 mm, and 30 aluminum foils were spot welded to a metal support of about 20 cm × 2 cm × 0.1 cm. A masking material solution having a width of 1 mm was applied on both sides in a circumferential manner so that the major axis direction of these aluminum conversion foils was divided into 4 mm and 5 mm portions, and dried to form a masking layer. A 3 mm × 4 mm portion of these chemical conversion foils was immersed in an aqueous solution of ammonium adipate and a voltage was applied to form a cut end portion to form a dielectric oxide film.
Separately, an isopropanol solution containing 3,4-ethylenedioxythiophene (hereinafter referred to as “monomer solution”) and an aqueous ammonium persulfate solution of sodium 2-anthraquinonesulfonate (hereinafter referred to as “oxidant solution”). Prepared, (1) a step of immersing the aluminum conversion foil in the monomer solution, (2) a step of removing isopropanol attached to the aluminum conversion foil, (3) a step of immersing the aluminum conversion foil in the oxidant solution, (4) The step of removing moisture from the oxidant solution adhering to the aluminum conversion foil was repeated to form a solid electrolyte layer made of a conductive polymer on the outer surface of the aluminum foil.

  Next, after washing and drying, a carbon paste and a silver paste were sequentially applied to a portion of the aluminum foil where the conductive polymer composition layer was formed, two aluminum foils were laminated, and a cathode lead terminal was connected. Moreover, the anode lead terminal was connected to the part in which the conductive polymer composition layer was not formed by welding, and the solid electrolytic capacitor element was obtained.

  The obtained capacitor element was heated at 200 ° C. for 10 minutes, sealed with an epoxy resin having a glass transition point of 170 ° C., and then heated at 150 ° C. for 30 minutes to perform a resin curing treatment. Next, aging was performed by applying a voltage of 25 V at 105 ° C., and baking was further performed at 120 ° C. for 5 hours to complete a total of 50,000 solid electrolytic capacitors having a rated voltage of 10 V.

Example 2:
In Example 1, the rating was the same as in Example 1 except that the humidification treatment was performed by leaving it in an atmosphere of 60% relative humidity and 60 ° C. for 3 hours before aging after curing after epoxy resin sealing. A total of 50,000 solid electrolytic capacitors with a voltage of 10 V were completed.

Example 3:
In Example 1, after curing after epoxy resin sealing and before aging, humidification is performed by leaving it in an atmosphere of 60% relative humidity and 60 ° C. for 3 hours, and heat treatment is performed at 210 ° C. for 10 seconds after firing. A total of 50,000 solid electrolytic capacitors with a rated voltage of 10 V were completed in the same manner as in Example 1 except for the above.

Example 4:
In Example 1, before curing after epoxy resin sealing and before aging, humidification treatment was performed by leaving it in an atmosphere of 60% relative humidity and 60 ° C. for 3 hours, followed by heat treatment at 210 ° C. for 10 seconds after firing, and then 105 A total of 50,000 solid electrolytic capacitors with a rated voltage of 10 V were completed in the same manner as in Example 1 except that re-aging was performed by repeating the voltage application at 25 ° C. 100 times.

Example 5:
In Example 1, before curing after epoxy resin sealing and before aging, humidification treatment was performed by leaving it in an atmosphere of 60% relative humidity and 60 ° C. for 3 hours, followed by heat treatment at 210 ° C. for 10 seconds after firing, and then 105 A total of 50,000 solid electrolytic capacitors with a rated voltage of 10 V were completed in the same manner as in Example 1 except that 100 ° C. and 25 V voltage application was repeated 100 times, and re-aging and 200 ° C. for 5 seconds were performed twice. It was.

Comparative Example 1:
In Example 1, a total of 5 solid electrolytic capacitors having a rated voltage of 10 V were obtained in the same manner as in Example 1 except that the resin was sealed without sealing before the epoxy resin was sealed and the aging condition was changed to a voltage of 18 V at 105 ° C. Completed 10,000 pieces.

Comparative Example 2:
In Example 1, before aging after epoxy resin sealing and after curing after epoxy resin sealing, the sample was left in an atmosphere of 60% relative humidity and 60 ° C. for 3 hours, and a voltage of 18 V was applied at 105 ° C. In the same manner as in Example 1 except that after baking, a heat treatment was performed at 210 ° C. for 10 seconds, a voltage application of 105 ° C. and 25 V was repeated 100 times, and then re-aging and a heat treatment at 200 ° C. for 5 seconds were performed twice. A total of 50,000 solid electrolytic capacitors with a rated voltage of 10 V were completed.

Test Method: Measurement of Leakage Current of Solid Electrolytic Capacitor The non-defective product of each capacitor prepared in Examples 1 to 5 and Comparative Examples 1 and 2 was fixed to a test glass epoxy substrate using a lead-free solder paste and reflowed. After passing through the furnace five times and cooling the substrate to room temperature, the leakage current was measured, and a capacitor having a leakage current value of 0.04 CV or more was determined as a defective product. In Examples 1 to 5, the leakage current was measured 1 minute after applying a voltage of 10 V, and in Comparative Examples 1 and 2 after 1 minute of applying a voltage of 10 V. The defect rate results are shown in Table 1.

  From Table 1, in Examples 1-5, compared with the case where the rated voltage is applied in Comparative Examples 1 and 2, although the leakage current was measured by applying a voltage 1.5 times the rated voltage or higher, It can be clearly seen that the leakage current failure rate is reduced.

Claims (8)

  Capacitor element obtained by using a metal having a valve action as an anode body, forming a dielectric film by chemical conversion treatment on at least a part of the surface, and sequentially forming a conductive polymer layer and a conductive paste layer as a cathode body A process for producing a solid electrolytic capacitor comprising a step of resin-sealing a capacitor element, wherein the capacitor element is heated at 180 ° C. or higher before resin-sealing.   The manufacturing method of the solid electrolytic capacitor of Claim 1 including the process of performing the hardening process of resin at the temperature below the glass transition point of the said resin after resin sealing.   The method for producing a solid electrolytic capacitor according to claim 1, further comprising a humidification process in an atmosphere having a relative humidity of 60% or more after the resin curing process.   The manufacturing method of the solid electrolytic capacitor in any one of Claims 1-3 including the process of applying the voltage of 1-5 times the rated voltage in the atmosphere of 50 degreeC or more after the hardening process of resin.   The manufacturing method of the solid electrolytic capacitor of Claim 4 including the process of heat-processing 180 degreeC or more after the said aging.   6. The solid electrolytic capacitor according to claim 5, further comprising a step of re-aging after applying the heat treatment at 180 ° C. or higher and applying a voltage 0.5 to 5 times the rated voltage at least once in an atmosphere at 0 ° C. or higher. Manufacturing method.   The manufacturing method of the solid electrolytic capacitor in any one of Claims 1-6 including the process of applying the voltage 1-5 times the rated voltage after the said re-aging, and removing the thing whose leakage current is 1 CV or more.   The solid electrolytic capacitor manufactured by the manufacturing method of the solid electrolytic capacitor in any one of Claims 1-7.