JP4811708B2 - Method for forming conductive polymer layer - Google Patents

Description

  The present invention relates to a method for forming a conductive polymer layer, a plate-like or foil-like member having a conductive polymer layer using the conductive polymer layer, particularly a method for producing a solid electrolytic capacitor including the conductive polymer layer, and a solid electrolytic capacitor .

  In recent years, with the digitization of electrical equipment and the speeding up of personal computers, small and large-capacity capacitors and low-impedance capacitors in the high-frequency region have been demanded. Recently, such capacitors have electronic conductivity. A solid electrolytic capacitor using a polymer as a solid electrolyte has been proposed.

  A basic element of a solid electrolytic capacitor is generally formed by forming a dielectric layer (oxide film) 2 on an anode substrate 1 made of a metal foil having a large specific surface area that has been etched, as shown in a sectional view in FIG. The masking layer 3 is partially formed, a solid semiconductor layer (hereinafter referred to as a solid electrolyte) 4 is formed as a cathode in one of the regions separated by the masking layer 3, and the other is used as an anode. . Usually, a conductor layer (not shown) such as a conductive paste is further formed on the solid electrolyte 4, and electrodes are appropriately added to the anode side and the cathode side, respectively. Here, the masking layer 3 is for ensuring insulation between the solid electrolyte (cathode portion) and the anode substrate.

  In general, electrolytic oxidation polymerization and chemical oxidation polymerization are known as methods for forming a solid electrolyte layer on a dielectric oxide film. Since the chemical oxidative polymerization method is easy to form a solid electrolyte and can be mass-produced in a short time, various methods have been proposed. For example, a method of forming a solid electrolyte having a layered structure by alternately repeating a step of immersing an anode substrate in a monomer-containing solution and a step of immersing in an oxidant-containing solution, without forming a solid electrolyte layer having a layered structure, As a method for forming a solid electrolyte in the pores and on the outer surface of a capacitor element, a method in which an anode substrate is immersed in a monomer compound-containing solution, polymerized in an oxidant solution, the oxidant is washed and then dried is repeated. It has been known.

In any of the above methods, since the solid electrolytic capacitor element conductor (anode base) includes an operation of immersing and pulling up in the monomer-containing solution or the oxidant-containing solution, it is necessary to efficiently perform the immersing and pulling-up operations. For this reason, normally, in the manufacture of a solid electrolytic capacitor element, a plurality of elements are processed simultaneously using a support member called a temporary bar. That is, as shown in Fig. 2, the support member (temporary bar) 11 may include a plurality of anode substrates 12 (dielectric coating layers), and the same applies to the following unless it is particularly necessary to distinguish the dielectric coating layers. ) Is attached by welding or the like (FIG. 2 (a)), the masking material 3 is applied to the upper part of the anode base body (FIG. 2 (b)), and is immersed in the treatment liquid tank 13 by the vertical movement of the temporary bar ( 2 (c)) and a pulling operation are performed to form a solid electrolyte layer having a required thickness, and then the anode substrate 12 is cut and separated from the remaining pieces 15 remaining on the temporary bar (FIG. 2 (d)). Element 14 is obtained.
As schematically shown in FIG. 3, a plurality of temporary bars are further processed together to improve efficiency. In FIG. 3, the capacitor element 12 fixed to the temporary bar at the back of the page is not visible, but a plurality of anode bases 12 are fixed to each temporary bar in the same manner as the temporary bar at the front of FIG. The surfaces of the anode substrate 12 thus formed are substantially parallel (see FIG. 4; FIG. 4 is a cross section of the adjacent anode substrate 12 present on AA ′ in FIG. 3).

  Although the above method is advantageous in that a large number of capacitor elements can be manufactured at once, a product with an abnormal electrical characteristic (for example, leakage current) of the capacitor may be generated, and there is a limit to improving the product yield. There was a problem that there was.

  The present invention provides a method for forming a conductive polymer layer that solves the above-described problems of the prior art and forms a conductive polymer layer with improved stability, thereby stabilizing the quality of the solid electrolytic capacitor. An object of the present invention is to provide a method of manufacturing a solid electrolytic capacitor that can be improved in productivity.

  As a result of intensive studies in view of the above problems, the present inventors have found that the element spacing (d in FIG. 4) is an important factor in forming the conductive polymer layer, and by limiting this to a certain range. The inventors have found that various characteristics of the capacitor are improved, and have completed the present invention. That is, this invention provides the formation method of the following conductive polymer layers, the manufacturing method of a solid electrolytic capacitor using the same, and a solid electrolytic capacitor.

1. In the method of arranging a plurality of plate-like or foil-like substrates in parallel and immersing them in a raw material liquid for forming a conductive polymer layer to form a conductive polymer layer on the substrate surface, A method for forming a conductive polymer layer, characterized in that the surface spacing is 20 times or more the thickness of the plate or foil.
2. 2. The method for forming a conductive polymer layer according to 1 above, wherein the plane interval of the plate or foil is in the range of 30 to 60 times the thickness of the plate or foil.
3. The raw material liquid for forming the conductive polymer layer is (i) a conductive polymer monomer-containing liquid, (ii) a conductive polymer monomer-containing liquid and an oxidizing agent-containing liquid, or (iii) a conductive polymer monomer. 3. The method for forming a conductive polymer layer according to 1 or 2 above, which is a combination of a containing liquid, an oxidizing agent-containing liquid and a counter anion-containing liquid having a dopant ability.
4). 4. The method for forming a conductive polymer layer according to any one of 1 to 3 above, wherein the base material is a valve action metal material having fine pores having a dielectric film formed on the surface.
5. 5. The method for forming a conductive polymer layer according to any one of 1 to 4, wherein the valve action metal material contains at least one metal selected from aluminum, tantalum, niobium, titanium, and zirconium.
6). The plate-like or foil-like base material is fixed to the lower side of the support member, and the plurality of support members to which the base material is fixed are held so that the base materials are parallel to be immersed in the raw material liquid. The formation method of the conductive polymer layer in any one of -5.
7). The manufacturing method of a solid electrolytic capacitor including the process of forming a conductive polymer layer on the surface using the method in any one of said 1-6.
8). The plate-shaped or foil-shaped member by which the conductive polymer layer was formed in the surface using the method in any one of said 1-6.
9. A solid electrolytic capacitor produced by the method described in 7 above, wherein the base material is a valve metal material having a fine hole having a dielectric film formed on the surface thereof.

  According to the method for forming a conductive polymer layer of the present invention, the polymerization reaction is appropriately controlled, and the shape and stability of the formed conductive polymer layer are improved. For this reason, if the method for forming a conductive polymer layer of the present invention is applied to a method for manufacturing a solid electrolytic capacitor, the stability of the conductive polymer layer functioning as the cathode of the solid electrolytic capacitor is increased, and the leakage current characteristic is deteriorated. Is prevented, and the shape, yield and reliability are improved.

Hereafter, each element and process which comprise the method of this invention are demonstrated.
As described above, when the conductive polymer layers are collectively formed on the surfaces of a plurality of base materials, these base materials are fixed to a support member, and a plurality of support members are processed together (for example, FIG. 3). ). Here, the support member 11 and the base material 12 are usually flat and have the same shape and dimensions. For this reason, as shown in FIG. 4 as a partial cross-sectional view, the surfaces of the base material 12 fixed to the adjacent support members 11 are substantially parallel.

In the present invention, the surface separation (d) is 20 times or more the thickness (t), whereby the concentration of the raw material liquid necessary for polymerization proceeds at an appropriate rate, and a stable polymerization reaction is realized. If the ratio d / t is less than the above value, that is, if the interplanar spacing is too wide compared to the substrate dimensions, the dry state necessary for concentration of the raw material solution will not be reached, and the conductive polymer layer will not be satisfactory in its shape and degree of polymerization. Become stable.
The plane spacing of the plate or foil may be 20 times or more the thickness of the plate or foil. However, when the ratio d / t is extremely large, the number of substrates that can be processed at the same time decreases, so that the production efficiency is improved. descend. 100 or less is preferable, and a range of 30 to 60 times is more preferable as a range in which drying proceeds stably. For example, when the thickness t of the substrate is about 100 μm, about 3 to 6 mm is a suitable range.

  The object to which the method for forming a conductive polymer layer of the present invention is applied is not particularly limited as long as it is a material capable of forming a conductive polymer on the surface thereof. However, since the method for forming the conductive polymer layer of the present invention is defined by the spacing between the plurality of base materials on which the conductive polymer layer is formed and the thickness of each base material, it is usually a plate and foil. Applied to the shaped member. However, as long as the spacing between the surfaces and the thickness of each substrate can be conceived, it can also be applied to columnar members and the like. The plate may be a sintered body or the like.

  In addition, the method for forming a conductive polymer layer of the present invention is particularly suitable as a method for producing a solid electrolytic capacitor. From this viewpoint, a base material for a solid electrolytic capacitor, typically a valve action having fine pores. Metal materials are preferred. The valve action metal is preferably selected from aluminum, tantalum, niobium, titanium, zirconium or alloys containing one or more thereof. In the method of manufacturing a solid electrolytic capacitor, these metals are subjected to an etching process or the like by a known method in advance to form fine holes on the surface.

  The dimensions are not limited as long as the above conditions are satisfied. For example, in the manufacturing process of a solid electrolytic capacitor, the material is cut into a size that matches the product shape, and generally has a thickness of about 40 to A foil having a thickness of 150 μm is used, and a foil in this range can be preferably used in the present invention. Similarly, although the size and shape vary depending on the application, a rectangular metal foil 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 for a solid electrolytic capacitor, and more preferably a width of about 2 -20 mm, length of about 2-20 mm, more preferably width of about 2-5 mm, and length of about 2-6 mm. However, the present invention is not limited to the production of a solid electrolytic capacitor, and can be widely applied when a polymerizable conductor layer is formed on the surface thereof.

  In order to adjust the ratio d / t within the above range, the substrate is fixed to the support member, and the distance between the plurality of support members may be controlled. As such a control method, for a base material having a predetermined thickness t, there is a method of inserting or fixing a support member into a frame body provided with grooves or fixing means so as to have a surface interval of 20 × t or more. . In order to make the parallelism between the substrates more reliable, a frame body having a space for accommodating the support member inside and having a groove for inserting the support member in the opposite wall surface of the space is preferable. Alternatively, an ear may be provided on the support member, and the ear portion may be gripped at a predetermined interval. Any method can be used as long as it is a method of holding a plurality of support members while maintaining them substantially in parallel. For example, a spacer having an appropriate size is inserted between the support members, and the whole is clamped. It may be fixed.

The present invention can be applied to both chemical oxidation polymerization and electrolytic oxidation polymerization. Therefore, the raw material liquid for forming the conductive polymer layer is
(i) a conductive polymer monomer-containing liquid (electrolytic oxidation polymerization),
(ii) a conductive polymer monomer-containing liquid and an oxidizing agent-containing liquid (chemical oxidative polymerization), or
(iii) Combination of a conductive polymer monomer-containing liquid, an oxidizing agent-containing liquid and a counter-anion-containing liquid having a dopant ability (chemical oxidative polymerization)
Either of these can be used.
As the material for forming the solid electrolyte layer, for example, a structure 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, etc. is repeated. Examples thereof include a conductive polymer contained as a unit. Although the conductive polymer which forms a solid electrolyte is not specifically limited, The polymer which contains the following compounds as a monomer as a suitable thing is mentioned.

  Examples of the compound 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, 3 , 4-methylenedioxythiophene, 3,4-ethylenedioxythiophene and the like. These compounds can be prepared by generally commercially available compounds or by known methods (for example, Synthetic Metals, 1986, Vol. 15, 169), but the present invention is not limited thereto.

  For example, as a compound having a polycyclic sulfide skeleton, specifically, a compound having a 1,3-dihydropolycyclic sulfide (also known as 1,3-dihydrobenzo [c] thiophene) skeleton, 1,3-dihydro A compound having a naphtho [2,3-c] 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-dihydronaphthaceno [2,3-c] thiophene skeleton can be exemplified, and a known method, For example, it can be prepared by the method described in JP-A-8-3156.

  In addition, for example, 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. The compound having a [2,3-c] thiophene skeleton may be a 1,3-dihydrobenzo [a] anthraceno [7,8-c] thiophene derivative.

  The condensed ring may optionally contain nitrogen or N-oxide, such as 1,3-dihydrothieno [3,4-b] quinoxaline or 1,3-dihydrothieno [3,4-b] quinoxaline-4-oxide 1,3-dihydrothieno [3,4-b] quinoxaline-4,9-dioxide, and the like, but are not limited thereto.

  Examples of the compound 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, but are not limited to these in the present invention.

  Examples of the compound having a furan skeleton include 3-methyl furan, 3-ethyl furan, 3-propyl furan, 3-butyl furan, 3-pentyl furan, 3-hexyl furan, 3-heptyl furan, 3-octyl furan, 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, but are not limited to these in the present invention.

  Examples of the compound 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, 3,4-butyleneaniline , Derivatives of 3,4-methylenedioxyaniline, 3,4-ethylenedioxyaniline, and the like. These compounds can be prepared commercially or by known methods, but are not limited to these in the present invention.

  A compound selected from the above compound group may be used in combination and used as a ternary copolymer. In this case, the composition ratio of the polymerizable monomer depends on the polymerization conditions and the like, and the preferred composition ratio and polymerization conditions can be confirmed by a simple test.

In this invention, the oxidizing agent used for manufacture of the conductive polymer used as a solid electrolyte should just be an oxidizing agent which can fully perform the oxidation reaction of a dehydrogenative four-electron oxidation reaction. Specifically, a compound that is industrially inexpensive and easy to handle in production is preferred. Specifically, for example, FeCl ₃ , FeClO ₄ , Fe (III) -based compounds such as Fe (organic acid anion) salt, anhydrous aluminum chloride / cuprous chloride, alkali metal persulfates, ammonium persulfates, peroxidation Products, manganese such as potassium permanganate, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetrachloro-1,4-benzoquinone, tetracyano-1,4-benzoquinone, etc. Quinones, halogens such as iodine and bromine, peracid, sulfuric acid, fuming sulfuric acid, sulfur trioxide, sulfonic acid such as chlorosulfuric acid, fluorosulfuric acid and amidosulfuric acid, ozone and the like, and combinations of these oxidizing agents. .

  Among these, the basic compound of the organic acid anion that forms the Fe (organic acid anion) salt includes organic sulfonic acid, organic carboxylic acid, organic phosphoric acid, and organic boric acid. Specific examples of the organic sulfonic acid include benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, α-sulfo-naphthalene, β-sulfo-naphthalene, naphthalene disulfonic acid, alkylnaphthalenesulfonic acid (alkyl group). As butyl, triisopropyl, di-t-butyl, etc.).

On the other hand, specific examples of the organic carboxylic acid include acetic acid, propionic acid, benzoic acid, and succinic acid. Furthermore, in the present invention, polyelectrolyte anions such as polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polyvinyl sulfonic acid, polyvinyl sulfuric acid, poly-α-methyl sulfonic acid, polyethylene sulfonic acid and polyphosphoric acid are also used. Examples of these organic sulfonic acids or organic carboxylic acids are merely examples and are not limited thereto. The counter cation of the anion is an alkali metal ion such as H ⁺ , Na ⁺ , K ⁺ , or an ammonium ion substituted with a hydrogen atom, a tetramethyl group, a tetraethyl group, a tetrabutyl group, a tetraphenyl group, etc. The present invention is not particularly limited. Among the oxidizing agents described above, particularly preferably, a trivalent Fe-based compound, or an oxidizing agent containing cuprous chloride, alkali persulfate, ammonium persulfate, manganic acid, and quinones can be suitably used.

In the present invention, in the production of a conductive polymer used as a solid electrolyte, a counter anion having a dopant ability that coexists as necessary is an oxidant anion (reduced form of an oxidant) produced from the oxidant. Examples thereof include electrolyte compounds possessed by ions or other anionic electrolytes. Specifically, for example, a halogenated anion of a group 5B element such as PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , a halogenated anion of a group 3B element such as BF ₄ ⁻ , I ⁻ (I ₃ ⁻ ), Br ⁻ Halogen anions such as Cl ⁻ , halogen acid anions such as ClO ₄ ⁻ , Lewis acid anions such as AlCl ₄ ⁻ , FeCl ₄ ⁻ and SnCl ₅ ⁻ , or inorganic acid anions such as NO ₃ ⁻ and SO ₄ ²⁻ , Or p-toluenesulfonic acid, naphthalenesulfonic acid, alkyl-substituted sulfonic acid having 1 to 5 carbon atoms, organic sulfonate anions such as CH ₃ SO ₃ ⁻ and CF ₃ SO ₃ ^— , or CF ₃ COO ⁻ , C ₆ H ₅ Mention may be made of protonic acid anions such as carboxylic acid anions such as COO ⁻ . Similarly, polymer electrolyte anions such as polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polyvinyl sulfonic acid, polyvinyl sulfuric acid, poly-α-methyl sulfonic acid, polyethylene sulfonic acid, and polyphosphoric acid can be cited. It is not necessarily limited.

  However, a high molecular or low molecular organic sulfonic acid compound or polyphosphoric acid is preferable, and an aryl sulfonate dopant is preferably used. For example, salts such as benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, anthracenesulfonic acid, anthraquinonesulfonic acid and derivatives thereof can be used.

The concentration of the monomer that forms the conductive polymer used in the solid electrolyte used in the present invention varies depending on the type of substituent of the compound, the type of solvent, etc., but is generally 10 ⁻³ to 10 mol / liter. A range is desirable, and a range of 10 ^{−2 to} 5 mol / liter is more preferable. The reaction temperature is determined by the reaction method and is not particularly limited, but is generally selected within a temperature range of -70 ° C to 250 ° C. Desirably, it is -30 degreeC-150 degreeC, and also it is desirable to carry out in the temperature range of -10 degreeC-30 degreeC.

  In the present invention, the reaction solvent used may be any solvent that can dissolve the monomer, the oxidizing agent, the counter-anion having the dopant ability, or each of them independently, for example, ethers such as tetrahydrofuran, dioxane, diethyl ether, or dimethyl Aprotic polar solvents such as formamide, acetonitrile, benzonitrile, N-methylpyrrolidone, dimethyl sulfoxide, esters such as ethyl acetate and butyl acetate, non-aromatic chlorinated solvents such as chloroform and methylene chloride, nitromethane and nitroethane Nitro compounds such as nitrobenzene, alcohols such as methanol, ethanol and propanol, organic acids such as formic acid, acetic acid and propionic acid or acid anhydrides of the organic acids (eg acetic anhydride), water, alcohols or Ton class or may be used a mixed solvent thereof. Further, the counter anion and / or monomer having the oxidizing agent and / or dopant ability may be handled in a solvent system dissolved independently, that is, a two-component system or a three-component system.

  The electric conductivity of the solid electrolyte thus produced is 1 S / cm or more, but it is 5 S / cm or more, more preferably 10 S / cm or more under desirable conditions.

  Further, a carbon paste layer and a metal powder-containing conductive layer are provided on the surface of the solid electrolyte layer to form the cathode portion of the capacitor. The metal powder-containing conductive layer is in close contact with the solid electrolyte layer and acts as a cathode, and at the same time serves as an adhesive layer for bonding the cathode lead terminal of the final capacitor product. The thickness of the metal-containing conductive layer is limited However, it is generally about 1 to 100 μm, preferably about 5 to 50 μm.

  The solid electrolytic capacitor has a lead terminal joined to a lead frame joined to the anode part, a lead wire joined to a cathode part made of a solid electrolyte layer, a carbon paste layer, and a metal powder-containing conductive layer, and the whole is made of an epoxy resin or the like. Obtained by sealing with an insulating resin.

  The capacitor element formed by the method of the present invention is usually used as a multilayer capacitor element. A multilayer solid electrolytic capacitor can be formed, for example, by stacking capacitor elements on a lead frame.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples.
(Example 1)
A 110 μm-thick chemical aluminum foil (3V chemical product) cut to 3.5 mm width was cut to a length of 13 mm, and one short side of this foil piece was fixed to a metal support by welding. The cut surface when cut from the formed aluminum foil was formed, and a polyimide resin for separating the anode part and the cathode part was applied linearly to a width of 0.8 mm centering on a part 5 mm from the tip of the aluminum foil and dried. Then, the solid electrolyte which is a cathode layer was formed as follows.
That is, using a jig in which 150 metal supports were arranged and fixed in parallel at intervals of 40 times the thickness of the porous element, the cathode part (3.5 mm × 4.6 mm) of the foil was connected to 3,4-ethylene diethylene. It was immersed in an isopropanol solution (solution 1) containing oxythiophene, pulled up and left standing. Next, it was immersed in an aqueous solution containing ammonium persulfate (solution 2), dried, and subjected to oxidative polymerization. The operation of immersing in solution 1 and then immersing in solution 2 and performing oxidative polymerization was repeated. The solid electrolyte layer was formed by washing with warm water at 50 ° C. and drying at 100 ° C. Further, an electrode was formed with a carbon paste and a silver paste at the cathode portion, thereby completing a capacitor element.

Two parts, including the applied masking material, are stacked on the lead frame while being joined with silver paste, and the anode lead terminal is connected to the part without the solid electrolyte by welding, and the whole is sealed with epoxy resin, at 135 ° C. A total of 30 chip-type solid electrolytic capacitors were produced by applying a voltage of 2 V and aging.
For these 30 capacitors, the initial characteristics were measured for capacity and loss factor (tan δ) at 120 Hz, equivalent series resistance (hereinafter referred to as ESR) at 100 kHz, and leakage current. The leakage current was measured 1 minute after applying the rated voltage of 2V. The measurement results were as follows.

Capacity (average value): 94.2 μF
tan δ (average value): 1.2%
ESR (average value): 11.4 mΩ
Leakage current (average value): 0.27 μA
The defective rate when a leakage current of 1 μA (0.005 CV) or more was regarded as a defective product was 5%.
Further, the results of a reflow test and a subsequent moisture resistance test are shown. The reflow test (also called solder heat resistance test) was evaluated by the following method. That is, 20 capacitor elements were prepared, and the elements were passed for 10 seconds at a temperature of 255 ° C., this operation was repeated three times, the leakage current after 1 minute application of the rated voltage was measured, and the value was 8 μA ( 0.04 CV) or higher was regarded as defective. The moisture resistance test was left for 500 hours in a high temperature and high humidity environment of 60 ° C. and 90% RH, and a leakage current value of 80 μA (0.4 CV) or higher after 1 minute application of the rated voltage was regarded as a defective product.

Leakage current after reflow test: 0.35 μA
Leakage current after moisture resistance test: 12.6 μA
In all cases, the defect rate was zero.
These results are shown in Tables 1-2 together with other examples.

(Example 2)
A capacitor element was manufactured and tested in the same manner as in Example 1 except that a jig in which 150 metal supports were arranged and fixed in parallel at intervals of a width 25 times the thickness of the porous element was used. The results are shown in Tables 1-2.

(Comparative Example 1)
A capacitor element was manufactured and tested in the same manner as in Example 1 except that a jig in which 150 metal supports were arranged and fixed in parallel at intervals of 10 times the thickness of the porous element was used. The results are shown in Tables 1-2.

  The present invention provides a method for forming a conductive polymer layer that forms a conductive polymer layer with improved stability. Therefore, although it is useful in various articles having a conductive polymer layer on the surface, the stability of the conductive polymer layer functioning as a cathode of the solid electrolytic capacitor is particularly applied by applying it to a method of manufacturing a solid electrolytic capacitor. This is useful because it prevents the deterioration of leakage current characteristics and contributes to the improvement of yield and reliability.

Sectional drawing which shows the outline of the structure of a solid electrolytic capacitor. The schematic diagram which shows the outline of the manufacturing process of a solid electrolytic capacitor. The schematic diagram which shows the outline of the manufacturing process in one embodiment of this invention. FIG. 4 is a view partially cut along A-A ′ in FIG. 3, and is a schematic diagram showing a surface interval (d) and a substrate thickness (t) of a substrate in the present invention.

Explanation of symbols

1 Anode substrate 2 Dielectric layer (oxide film)
3 Masking Layer 4 Solid Electrolyte Layer 5 Solid Electrolytic Capacitor Element 10 Support Member (Temporary Bar)
11 Treatment liquid

Claims (9)

In the method of arranging a plurality of plate-like or foil-like substrates in parallel and immersing them in a raw material liquid for forming a conductive polymer layer to form a conductive polymer layer on the substrate surface, A method for forming a conductive polymer layer, characterized in that the face spacing is 20 to 100 times the thickness of the plate or foil.

  The method for forming a conductive polymer layer according to claim 1, wherein an interval between the plates or the foils is in a range of 30 to 60 times the thickness of the plates or the foils.   The raw material liquid for forming the conductive polymer layer is (i) a conductive polymer monomer-containing liquid, (ii) a conductive polymer monomer-containing liquid and an oxidizing agent-containing liquid, or (iii) a conductive polymer monomer. The method for forming a conductive polymer layer according to claim 1 or 2, which is a combination of a containing liquid, an oxidizing agent-containing liquid and a counter anion-containing liquid having a dopant ability.   The method for forming a conductive polymer layer according to any one of claims 1 to 3, wherein the base material is a valve metal material having fine pores having a dielectric film formed on a surface thereof.   The method for forming a conductive polymer layer according to any one of claims 1 to 4, wherein the valve metal material includes at least one metal selected from aluminum, tantalum, niobium, titanium, and zirconium.   A plurality of plate-like or foil-like base materials are fixed to a lower side of a support member, and the plurality of support members to which the base materials are fixed are held so that the base materials are parallel to be immersed in the raw material liquid. The formation method of the conductive polymer layer in any one of 1-5.   The manufacturing method of a solid electrolytic capacitor including the process of forming a conductive polymer layer on the surface using the method in any one of Claims 1-6.   The plate-shaped or foil-shaped member in which the conductive polymer layer was formed on the surface using the method in any one of Claims 1-6. The solid electrolytic capacitor manufactured by the method according to claim 7, wherein the base material is a valve action metal material having fine pores having a dielectric film formed on a surface thereof.

Images