JPH0974050A - Capacitor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a high-capacity accomplishment rate, a low loss, a low impedance, a high breakdown strength, and a high heat resistance regarding a capacitor with a conductive macromolecular layer containing pyrrole or its derivative and its manufacturing method. SOLUTION: A method for manufacturing a capacitor has a chemical polymerization process for forming a capacitor which has a pair of electrodes being provided while they oppose each other, a dielectric layer being provided between the electrodes, and a conductive macromolecular layer which contains pyrrole or its derivative as a repetition unit and contains polyvalent anion and monohydric anion as dopants in at least one of the electrodes and its conductive macromolecular layer in the mixed medium of water and alcohol by chemical polymerization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized large-capacity capacitor having excellent capacitor characteristics such as frequency characteristics and withstand voltage characteristics, and a method for manufacturing the same, in which at least one electrode is made of a mixed dopant composed of a polyvalent anion and a monovalent anion. The present invention relates to a capacitor composed of a doped conductive polymer or additionally manganese dioxide, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, with the digitization of electric equipment,
As for the capacitor, a capacitor having a small size, a large capacity, and a low impedance in a high frequency region is required.

Conventionally, capacitors used in the high frequency region include plastic capacitors, mica capacitors, and laminated ceramic capacitors, but these capacitors have a large shape and it is difficult to increase the capacity.

On the other hand, as a large-capacity capacitor, there is an aluminum dry electrolytic capacitor or an electrolytic capacitor such as an aluminum or tantalum solid electrolytic capacitor.

In these capacitors, since the oxide film serving as a dielectric is extremely thin, a large capacity can be realized. On the other hand, since the oxide film is easily damaged, it is a true cathode for repairing it. It is necessary to provide an electrolyte that also serves as the.

[0006] For example, in an aluminum dry capacitor, an etched anode and cathode aluminum foil is wound around a separator, and a liquid electrolyte is impregnated into the separator for use.

Since this liquid electrolyte has ionic conductivity and a large specific resistance, it has a problem that the loss is large and the frequency characteristic and temperature characteristic of impedance are remarkably inferior.

In addition, there is a problem that liquid leakage and evaporation are unavoidable, and the capacity decreases and the loss increases with the passage of time.

Further, in the tantalum solid electrolytic capacitor,
Since manganese oxide is used as an electrolyte, problems with temperature characteristics and changes with time such as capacity and loss are improved, but since the specific resistance of manganese oxide is relatively high, the frequency characteristics of loss and impedance are It was inferior to ceramic capacitors or film capacitors.

In addition, in the tantalum solid electrolytic capacitor, when forming an electrolyte composed of manganese oxide,
The step of thermally decomposing at a temperature of about 300 ° C. after immersion in a manganese nitrate solution needs to be repeated several times to ten times, and the forming step is complicated.

Therefore, in recent years, after forming a conductive polymer such as a metal, a metal oxide having conductivity, or polypyrrole on the dielectric film, the conductive polymer such as polypyrrole is formed by electrolytic polymerization through the conductive layers. A solid electrolytic capacitor formed of a conductive polymer has been proposed (JP-A-63-1).
58829, JP-A-63-173313, JP-A-1-253226 and the like.

Furthermore, a large-capacity film capacitor in which a conductive polymer layer is sequentially formed by chemical polymerization and electrolytic polymerization after forming a dielectric made of an electrodeposited polyimide thin film on an etched aluminum foil to form an electrode. Has been proposed (Abstracts of the 58th Conference of the Electrochemical Society of Japan, pp. 251-252 (1991)).

[0013]

However, when an electrolytically polymerized polymer is formed via a conductive pyrolyzed metal oxide such as manganese oxide, the dielectric film is damaged by heat, resulting in a high temperature. In order to obtain a withstand voltage capacitor, it is necessary to perform chemical conversion again before electrolytic polymerization and to repair it, which causes a problem that the process becomes complicated.

Furthermore, in a tantalum solid electrolytic capacitor, an electrolyte made of manganese oxide is repeatedly formed by thermal decomposition, and chemical conversion is required each time to repair the film damage that has occurred, which complicates the process. Had challenges.

Further, as described above, in the method of forming an appropriate conductive layer in advance and then forming the electropolymerized conductive polymer layer via the appropriate conductive layer, there is a problem that the process becomes complicated. Was there.

In addition, when forming a conductive polymer layer by chemical polymerization, it is difficult to form a conductive polymer layer having a high filling rate up to the deep portion of the pores of the etched aluminum foil and the tantalum sintered body. there were.

Further, when a highly conductive electrolyte is used, there is a concern that the withstand voltage characteristic may be deteriorated.

The present invention solves the above-mentioned problems in the prior art. It is possible to easily obtain a solid electrolytic capacitor having a high capacity achievement rate and high heat resistance and moisture resistance, and a small capacity with a high capacity achievement rate and a high heat resistance. The purpose is to easily obtain a film capacitor having high moisture resistance.

[0019]

DISCLOSURE OF THE INVENTION According to the present invention, at least one of a pair of electrodes facing each other, a dielectric layer provided between the electrodes, and at least one of the electrodes is a repeating unit containing pyrrole or a derivative thereof. And a conductive polymer layer containing a polyvalent anion and a monovalent anion as dopants.

A conductive layer made of polypyrrole containing a polyvalent anion and a monovalent anion as a dopant is preferably produced by chemical polymerization.

Further, the chemical polymerization is preferably carried out by a production method which is carried out in a medium containing water and alcohol.

With the above structure, it is possible to easily obtain a solid electrolytic capacitor having a high capacity achievement rate and high heat and humidity resistance.
Further, it is possible to easily obtain a small-sized and large-capacity film capacitor having a high capacity achievement rate and high heat and humidity resistance.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention according to claim 1, wherein at least one of a pair of electrodes provided facing each other, a dielectric layer provided between the electrodes, and the electrode is pyrrole or a derivative thereof. Is a repeating unit, and a conductive polymer layer containing a polyvalent anion and a monovalent anion as dopants.

Thus, in the capacitor whose dielectric is composed of the oxide film of the valve metal, polypyrrole functions as an electrolyte which also functions as a true cathode, while in the capacitor which is composed of a polymer thin film, a simple electrode is used. Function as.

Further, the conductive polymer layer contains a polyvalent anion and a monovalent anion as dopants. For example, when an anionic surfactant is used as the surfactant, the monovalent anion dissociated from the anionic surfactant is, for example, an oxidizing agent. This is because it was incorporated into the polymerized polypyrrole in a competitive manner with the polyvalent anion of the transition metal polyvalent acid salt used as.

The polyvalent anion is supplied from a polyvalent acid salt of a transition metal which acts as an oxidizing agent, and examples of the transition metal include iron (III), copper (II), chromium (VI) and cerium (IV). , Ruthenium (III) and manganese (VII) can be used.

As the polyvalent acid, sulfuric acid, phosphoric acid, permanganic acid, chromic acid, dichromic acid or the like can be used.

Here, it is preferable that the polyvalent anion is a sulfate group.

Further, as described in claim 3, the monovalent anion is preferably a sulfonic acid group, and further,
It is preferably an aromatic sulfonic acid group.

Further, as described in claim 4, it is preferable that the sulfonic acid group is dissociated from the anionic surfactant.

Further, as described in claim 5, the dielectric layer may be an oxide of a valve metal forming one of the electrodes.

In this case, as described in claim 6, it is preferable that the valve metal is aluminum or tantalum.

Further, as described in claim 7, the dielectric layer may be a polymer film. In this case, as described in claim 8, the polymer film is preferably a polyimide film. is there.

Further, as described in claim 9, a manganese dioxide layer may be further provided between the dielectric and the conductive polymer layer.

With the above structure, a capacitor having a high capacity achievement rate and high heat and humidity resistance can be obtained.

On the other hand, as a concrete manufacturing method of the capacitor, as described in claim 10, a step of disposing a pair of electrodes facing each other, and a dielectric layer forming step of forming a dielectric layer between the electrodes. , At least one of the electrodes,
Of a capacitor having a chemical polymerization step of forming a conductive polymer layer of a capacitor having a repeating unit of pyrrole or a derivative thereof and having a polyvalent anion and a monovalent anion as a dopant by chemical polymerization It is a manufacturing method.

As described above, since polypyrrole is formed by chemical polymerization in a solution at room temperature, damage to the dielectric layer due to heat is prevented.

When the dielectric layer is composed of an oxide film of a valve metal, it is necessary for each treatment of thermal decomposition to be repeated when forming a manganese oxide layer by conventional thermal decomposition. Even if the repair chemical treatment is omitted, a solid electrolytic capacitor with low leakage current can be easily obtained.

In addition, as another basic method of manufacturing a capacitor, which is basically the same, a step of disposing a pair of electrodes facing each other as described in claim 11 and a dielectric material between the electrodes. Conductivity of a capacitor having a dielectric layer forming step of forming a layer, and a conductive polymer layer containing a polyvalent anion and a monovalent anion as a dopant, in at least one of the electrodes, a repeating unit of pyrrole or a derivative thereof. A method for producing a capacitor, which comprises a chemical polymerization step of forming a conductive polymer layer by chemical polymerization in a medium containing water and alcohol.

Thus, when the polymerization medium contains alcohol, a water-insoluble salt composed of the transition metal cation of the transition metal polyvalent acid salt acting as an oxidizing agent and the anion of the anionic surfactant is formed. Even in this case, it becomes possible to dissolve it, and the polymerization solution phase is kept uniform without causing precipitation.

This prevents the insoluble component from etching the surface of the electrode having the dielectric coating or blocking the pores of the sintered body from lowering the coverage of the conductive polymer.

It is also possible to control the polymerization reaction rate of polypyrrole to be small depending on the amount of alcohol added.

Therefore, the conductive polymer layer is mainly and reliably formed in the vicinity of the electrode surface layer, and it is difficult to form it in the etching pits or in the deep portions of the sintered body pores, which is a problem in the aqueous medium. Non-uniformity can be improved.

When an aqueous medium is used, in order to prevent the non-uniformity of the conductive polymer, the concentration of the monomer and the oxidizing agent should be lowered and the number of repetitions for forming the conductive polymer layer should be increased. However, by using a mixed solvent of water and alcohol, it is possible to avoid non-uniformity due to the site of the electrode of polypyrrole generation even if the concentration is increased, so that the high capacity achievement rate can be achieved with a small number of polymerization repetitions. To realize the capacitor.

Here, as described in claim 12, it is preferable that the alcohol is one selected from methanol, ethanol, propanol, ethylene glycol, propylene glycol or glycerin or a mixture thereof.

Further, as described in claim 13, in the chemical polymerization step, the conductive polymer layer may be formed using a solution containing pyrrole or a derivative thereof, ferric sulfate and an anionic surfactant. It is suitable.

By thus including the surfactant in the polymerization solution, the polypyrrole layer can be formed even in the fine pores deep on the surface enlarged by etching or sintering, so that the coverage can be increased. A high-capacity capacitor is realized.

Furthermore, since an anionic surfactant is used as the surfactant, the monovalent anion dissociated from the anionic surfactant is used as an oxidant in the polymerized polypyrrole. And will be taken competitively.

The anion of the anionic surfactant contains a hydrophobic group and has a large ionic size. Due to this large ionic size dopant, dedoping due to diffusion at high temperature or high humidity is suppressed. As a result, a polypyrrole with less deteriorated conductivity is formed, and a capacitor having excellent heat resistance and humidity resistance can be obtained.

Since the anion of the surfactant is monovalent, it is more likely to be incorporated as a dopant in polypyrrole than the polyvalent anion generated from the oxidizing agent.

Therefore, the ratio of the monovalent anion to the total dopant depends more strongly on the surfactant concentration than on the oxidant concentration, and the ratio can be adjusted by changing this concentration.

The electric conductivity of the polypyrrole and its stability tend to be improved as the doping ratio of the monovalent anion having a large molecular size based on the surfactant is increased.

Therefore, as compared with the case of using polypyrrole polymerized with a transition metal polyvalent acid salt and the case of using manganese dioxide, a capacitor having greatly improved high frequency characteristics and loss characteristics can be easily obtained. .

As described in claim 14, it is preferable to use an anionic surfactant containing an anion having a sulfonic acid group, and further it is preferable to use an aromatic sulfonic acid group. .

Further, as in the fifteenth aspect, the dielectric forming step may form the dielectric by anodic oxidation of the valve metal.

In this case, as described in claim 16, the valve metal forming one of the electrodes may be aluminum or tantalum.

Alternatively, as in the seventeenth aspect, the dielectric forming step may form the dielectric by using a polymer thin film.

In this case, it is preferable that the polymer is polyimide.

Further, as described in claim 19, in the chemical polymerization step, the chemical polymerization may be further carried out using a solution containing phenol or a derivative thereof.

As described above, the addition of phenol or its derivative further improves the electric conductivity and stability of the obtained polypyrrole.

It is considered that this is because the phenolic compound is not incorporated as a dopant in the polypyrrole, but it produces polypyrrole having a high regularity and therefore a conjugation length. As a result, the phenolic derivative is produced. The initial characteristics and stability of the capacitor using the polypyrrole obtained from the polymerization system to which is added are further improved.

Here, as described in claim 20, the phenol derivative is nitrophenol, cyanophenol,
It is preferably hydroxybenzoic acid, hydroxyphenol or acetophenol, or a combination thereof.

Further, as described in claim 21, the method may further include a manganese dioxide layer forming step of forming a manganese dioxide layer between the dielectric and the conductive polymer layer by thermal decomposition. .

In this way, at the interface between the dielectric and the conductive polymer synthesized from polypyrrole or its derivative,
The inclusion of thin manganese dioxide reduces the rate of increase in leakage current that increases with applied voltage due to its relatively low electrical conductivity.

Further, as described in claim 22, in the manganese dioxide layer forming step, the manganese dioxide layer may be formed by reduction of permanganate.

Each embodiment of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) In the present embodiment, first, a solution of a 2 × 1.4 × 0.9 mm tantalum sintered body in which 5 ml of phosphoric acid is dissolved in 1000 ml of water is used and the temperature is about 90 ° C. 40 V was applied to form an oxide film dielectric layer by anodic oxidation.

When this structure was regarded as a capacitor and the capacity in the chemical conversion liquid was measured, it was 17 μF.

Further, by using this constitution, 0.75 mol / l of a pyrrole monomer and a surfactant of sodium alkylnaphthalene sulfonate (average molecular weight of 338) were added to 0.10 mol.
After dipping in a 75 wt% monomer aqueous solution, it was dipped in an oxidant solution containing ferric sulfate 0.75 mol / l and the above surfactant in an amount of 0.75 wt%.

This treatment was repeated to form a conductive layer made of polypyrrole doped with divalent sulfate ions and monovalent alkylnaphthalene sulfonate ions.

Here, FIG. 1 shows changes in the yield and electrical conductivity of polypyrrole obtained when the addition amount of sodium alkylnaphthalene sulfonate was changed.

As shown in FIG. 1, as compared with the case where no surfactant is added, the addition of the surfactant increases the yield and electrical conductivity of polypyrrole, so that the monovalent alkylnaphthalene sulfonate ion is added. You can see that it is doped.

From the elemental analysis, it was confirmed that iron was not substantially contained in this polymerization product, and that the sulfur / nitrogen ratio increased with an increase in weight.

Further, the monovalent sulfonate ion in the surfactant competes with the divalent sulfate ion and is incorporated as a dopant, and the respective doping ratios do not change depending on the polymerization conditions. It is possible to calculate from the sulfur / nitrogen ratio determined from elemental analysis under the assumption that the molar ratio of the sulfate ion of the dopant to the alkylnaphthalene sulfonate ion when polymerized with the composition used for the prototype capacitor is It was 1: 4.2.

Then, on the tantalum sintered body on which the polypyrrole was formed in this way, a cathode was formed with a carbon layer and a silver paint layer, and a cathode lead was attached thereon.
A total of 10 capacitor elements were obtained.

Further, the device was packaged with an epoxy resin and further subjected to an aging treatment at 125 ° C. with 13 V applied to complete a capacitor.

With respect to these 10 elements, the capacitance at 1 kHz, the loss coefficient, and the impedance at 400 kHz were measured, and the rate of change in capacitance and the loss coefficient after a load heat resistance test performed at 10 ° C. by applying 10 V were measured. However, the average value thereof is shown in (Table 1) below.

[0078]

[Table 1] Comparative Example 1 Next, for comparison, 10 capacitors were completed under the same conditions as in Embodiment 1 except that sodium alkylnaphthalene sulfonate was not added as Comparative Example 1.

The capacitance, loss factor, and impedance at 400 kHz of each of these 10 elements were measured, and their average values are shown in (Table 1) above.

(Embodiment 2) This embodiment has the same structure as that of Embodiment 1 except that sodium dodecylbenzene sulfonate is used in place of sodium alkylnaphthalene sulfonate in Embodiment 1. Completed 10 capacitors and measured the capacitance at 1 kHz, loss factor, and impedance at 400 kHz, and measured the rate of change in capacitance and loss factor after load heat resistance test performed by applying 10 V at 125 ° C. However, the average value thereof is shown in the above (Table 1).

As can be seen from Table 1, also in the present embodiment, the addition of the anionic surfactant to the polymerization solution improves the permeability into the sintered body and further A conductive layer made of polypyrrole doped with a monovalent anion, dodecylbenzenesulfonic acid, partially substituted with the divalent sulfate ion is formed.

The electrical conductivity and thermal stability of this polypyrrole are higher than those when doped with sulfate ions only.

As a result, it is possible to obtain a capacitor having a high capacity achievement rate, a low loss, a high frequency impedance characteristic, and a high heat resistance.

(Embodiment 3) In the present embodiment, 10 electrodes are used under the same conditions as in Embodiment 1 except that the following etched aluminum foil electrode is used in place of the tantalum sintered body of Embodiment 1. Capacitor was completed and the same characteristic evaluation was performed, and the results are shown in (Table 1) above.

A specific method for producing an aluminum electrode foil is as follows. First, a polyimide tape 7 having a width of 1 mm is attached to both sides of a 4 × 10 mm2 aluminum etched foil so as to be divided into 3 mm and 6 mm portions.

Next, 4 × 3 of aluminum etched foil 1
The anode lead of the portion of mm was attached, and the portion of 4 × 6 mm of the aluminum etched foil was applied with 50% V at about 70 ° C. using an aqueous solution of 3% ammonium adipate to form an oxide film dielectric layer by anodic oxidation.

When this structure was regarded as a capacitor and the capacity in the chemical conversion liquid was measured, it was 4.7 μF.

As is clear from (Table 1), also in the present embodiment, the addition of the anionic surfactant into the polymerization solution improves the permeability into the sintered body, and the monovalent An anion, dodecylbenzenesulfonic acid, is formed into a conductive layer made of polypyrrole doped with the divalent sulfate ion partially substituted.

The electrical conductivity and thermal stability of this polypyrrole are higher than those when doped with sulfate ions only.

As a result, it is possible to obtain a capacitor having a high capacity achievement rate, a low loss, a high frequency impedance characteristic, and a high heat resistance.

(Embodiment 4) In the present embodiment, in the structure of Embodiment 3, a thickness of 0.5 μm is formed by spin coating instead of forming an oxide film dielectric on an aluminum smooth foil of 20 mm × 20 mm. 10 is used under substantially the same conditions as those of the third embodiment except that the electrode having the polyimide dielectric layer made of the polyimide thin film is used.
Individual capacitors were produced.

The same evaluations as in the third embodiment were carried out on these, and the results are shown in (Table 1) above.

As can be understood from this (Table 1), also in the present embodiment, by adding the anionic surfactant to the polymerization solution, the monovalent anion, the alkylnaphthalene sulfonate ion, becomes 2 A conductive layer made of polypyrrole doped with valence sulfate ions partially substituted is formed.

The electrical conductivity of this polypyrrole is higher than that when it is doped with sulfate ions only.

As a result, it is possible to obtain a capacitor element having low loss and excellent high frequency impedance characteristics.

(Embodiment 5) In this embodiment, in the structure of Embodiment 1, 0.1% is added to the monomer solution.
except that mol / l p-nitrophenol was added.
Ten capacitor elements were completed in the same manner as in the first embodiment.

Capacity at 1 kHz, loss factor, and 4
The impedance at 00 kHz was measured, and the rate of change in capacity and loss coefficient after a load heat resistance test performed by applying 10 V at 125 ° C. were measured, and their average values are shown in (Table 1) above.

FIG. 2 shows the relationship between the electrical conductivity and the yield with respect to the amount of sodium alkylnaphthalene sulfonate added when p-nitrophenol was added to the composition of the first embodiment.

The electric conductivity at this time is obviously higher than that in the case where p-nitrophenol was not added.

From the elemental analysis, it was found that the composition of the polypyrrole obtained by adding p-nitrophenol was not changed, and it was not incorporated as a dopant.

As can be seen from (Table 1), the capacitor according to this example has a permeability to the sintered body by adding the anionic surfactant and p-nitrophenol to the polymerization solution. Further, the monovalent anion is further doped with the monovalent anion partially substituted with the divalent sulfate ion to form a conductive layer made of polypyrrole with further improved electric conductivity.

The electrical conductivity of this polypyrrole is higher than that when it is doped with only sulfate ions, and the thermal stability is high.

With these, it is possible to obtain a capacitor element having a high capacity achievement rate, a low loss, a high frequency impedance characteristic and a high heat resistance.

(Embodiment 6) In the present embodiment, p-nitrophenol in the fifth embodiment is replaced by p
10 capacitors were completed in the same manner as in Embodiment 5 except that cyanophenol (A), m-hydroxybenzoic acid (B), m-hydroxyphenol (C) and acetophenol (D) were added. It was

Capacity at 1 kHz, loss factor, and 4
The impedance at 00 kHz was measured, and the rate of change in capacity and the loss coefficient after a load heat resistance test performed by applying 10 V at 125 ° C. were measured, and their average values are shown in (Table 1) above.

As can be seen from Table 1, in the capacitor according to the present embodiment, the anionic surfactant and the phenol derivative are added to the polymerization solution to improve the permeability into the sintered body. Then, the monovalent anion is further doped with the divalent sulfate ion partially substituted to form a conductive layer made of polypyrrole having a further improved electric conductivity.

The electric conductivity of this polypyrrole is higher than that when it is doped with only sulfate ions, and the thermal stability is high.

As a result, it is possible to obtain a capacitor element having a high capacity achievement rate, a low loss, an excellent high frequency impedance characteristic, and a high heat resistance.

(Embodiment 7) This embodiment is the same as Embodiment 1 except that in Embodiment 1, cupric sulfate having the same concentration is used instead of ferric sulfate. Completing the configured 10 capacitor elements, 1k
Measure the capacitance at Hz, the loss factor, and the impedance at 400 kHz, and then measure at 125 ° C for 10
The rate of change in capacity and the loss coefficient after the load heat resistance test performed by applying V were measured, and their average values are shown in the above (Table 1).

As described above, also in this embodiment,
By adding an anionic surfactant to the polymerization solution, the permeability into the sintered body is improved, and the monovalent anion, dodecylbenzene sulfonic acid, is partially substituted with the divalent sulfate ion. A conductive layer of polypyrrole doped with is formed.

The electrical conductivity of this polypyrrole and its thermal stability are higher than those when doped with sulfate ions only.

As a result, it is possible to obtain a capacitor having a high capacity achievement rate, a low loss, a high frequency impedance characteristic, and a high heat resistance.

(Embodiment 8) In the present embodiment, the tantalum sintered body electrode in Embodiment 1 is immersed in a 30% aqueous solution of manganese nitrate at 250 ° C. after anodic oxidation.
Ten capacitors were completed in the same manner as in Embodiment 1 except that the manganese dioxide layer was formed by thermal decomposition in step 1.

Capacity at 1 kHz, loss factor, and 4
The impedance at 00 kHz was measured, and the average value thereof was shown in the above (Table 1).

The leakage current when a rated voltage of 10 V was applied was 2.8 nA. On the other hand, the leakage current of the capacitor under the same conditions obtained in the first embodiment is 3.1 n.
It was A, which showed extremely low leakage current characteristics almost equal to each other.

Further, when the leak current was measured by changing the applied voltage of both of them from 1 V to 16 V, it was shown that the logarithmic value of the leak current was proportional to the half power of the applied voltage.

However, the former one has the gradient,
The tendency was 0.93, which was smaller than the latter value of 1.13.

This is an effect due to the inclusion of a manganese dioxide layer having a relatively low electric conductivity, and it can be expected to suppress a short circuit when a high voltage is applied.

On the other hand, as is clear from (Table 1), the increase of the loss coefficient due to the inclusion of the manganese dioxide layer is extremely slight.

It is considered that this is because the thickness of the formed manganese dioxide layer was extremely thin.

(Embodiment 9) In this embodiment, after forming the anodic oxide film on the electrode foil in Embodiment 3, a 12% aqueous solution of sodium permanganate is used to contain a pyrrole monomer and sodium alkylnaphthalene sulfonate. A capacitor was produced in the same manner as in Embodiment 3 except that reduced manganese dioxide was formed in the solution.

Also in this case, similarly to the eighth embodiment, it was recognized that the rate of increase of the leakage current with respect to the applied voltage was lower than that of the polypyrrole layer alone.

(Embodiment 10) In the present embodiment, first, a solution of 2 × 1.4 × 0.9 mm tantalum sinter is dissolved at a temperature of about 90 ° C. using a solution of 5 ml of phosphoric acid dissolved in 1000 ml of water. 40 V was applied to form an oxide film dielectric layer by anodic oxidation.

When this structure was regarded as a capacitor and the capacity in the chemical conversion liquid was measured, it was 17 μF.

Further, by using this constitution, 5 g of a pyrrole monomer, 1.6 g of a sodium alkylnaphthalene sulfonate sulfonate (average molecular weight 338) and 90 g of water are used.
After dipping in a monomer solution containing 10 g of ethanol and ferric sulfate, 7.9 g of ferric sulfate hydrate (water content 74%), 1.6 g of the surfactant, 90 g of water, and 10 g of ethanol were dipped in an oxidizing agent solution.

This treatment was repeated to form a conductive layer made of polypyrrole doped with divalent sulfate ions and monovalent alkylnaphthalene sulfonate ions.

The number of repetitions required for forming the conductive layer was 15 times. Here, FIG. 3 shows changes in the yield and electrical conductivity of polypyrrole obtained by polymerizing at 25 ° C. for 15 minutes when the concentration of ethanol added to the entire solvent consisting of water and ethanol of this embodiment was changed. Indicates.

As shown in FIG. 3, it is clear that the yield of polypyrrole decreases depending on the concentration boundary of ethanol addition. On the other hand, it is also shown that there is almost no change in electrical conductivity.

FIG. 4 shows the yield of polypyrrole and the electric potential obtained when the polymerization was carried out for 1 hour by changing the addition amount of sodium alkylnaphthalene sulfonate in a medium containing water containing 10% ethanol and ethanol at 25 ° C. Shows the change in conductivity.

As shown in FIG. 4, as compared with the case where no surfactant is added, the addition of the surfactant increases the yield and electrical conductivity of polypyrrole, so that the monovalent alkylnaphthalene sulfonate ion is added. It is understood that it is doped.

FIG. 5 is a comparison of the effects of the presence or absence of addition of sodium alkylnaphthalene sulfonate on the stability of electrical conductivity when polypyrrole is held in air at 125 ° C.

As shown in FIG. 5, it can be understood that the stability of the electrical conductivity of polypyrrole is dramatically improved by the addition of the surfactant as compared with the case where the surfactant is not added.

From the elemental analysis, it was confirmed that iron was not substantially contained in this polymerization product, and that the sulfur / nitrogen ratio increased with the increase in weight.

Then, a carbon layer and a silver paint layer were used to form a cathode on the polypyrrole-formed tantalum sintered body, and a cathode lead was attached thereon to obtain a total of 10 capacitor elements. It was

Further, the element was packaged with an epoxy resin and further subjected to an aging treatment at 125 ° C. with 13 V applied to complete a capacitor.

For these 10 elements, the capacitance at 1 kHz, the loss factor, and the impedance at 400 kHz were measured, and the rate of change in capacitance and the loss factor after a load heat resistance test performed at 10 ° C. at 125 ° C. were measured. The average values are shown in (Table 2) below.

[0137]

[Table 2] (Comparative Example 2) Next, for comparison, 10 capacitors were completed under the same conditions as in Embodiment 1 except that the whole amount of the aqueous medium was used instead of the addition of ethanol in Comparative Example 2. The number of repeated treatments required for forming the polypyrrole conductive layer was 11
It was once.

The capacitance at 1 kHz, the loss factor, and the impedance at 400 kHz were measured for each of these 10 elements, and their average values are shown in Table 2 above.

Comparative Example 3 Further, for comparison, as Comparative Example 3, except that sodium alkylnaphthalene sulfonate was not added, the same conditions as in Embodiment 1 were used.
Completed individual capacitors.

The capacitance at 1 kHz, the loss factor, and the impedance at 400 kHz were measured for each of these 10 elements, and their average values are shown in (Table 2) above.

As can be seen from Table 2, in Embodiment 10, by adding ethanol to the polymerization solution medium, the polymerization rate was moderately delayed, and further, the action of the sulfonic acid type surfactant was observed. Since the permeability into the sintered body is improved, the formation of the polypyrrole layer is facilitated even in the etching pits or deep portions of the sintered body pores, and the monovalent anion, alkylnaphthalene sulfonic acid, is added to the divalent sulfuric acid. A conductive layer made of polypyrrole doped with some of the ions replaced is formed.

Therefore, a capacitor having a high capacity achievement rate can be obtained. Furthermore, it can be understood from FIGS. 4 and 5 that the electrical conductivity and thermal stability of the polypyrrole of the first embodiment are larger than those in the case where only the sulfate ions are doped.

Therefore, it is possible to obtain a capacitor having low loss, excellent high frequency impedance characteristics, and excellent heat resistance.

When water alone is used as the medium, it is considered that a capacitor having a high capacity achievement rate cannot be obtained because the polymerization reaction proceeds before the oxidant has sufficiently penetrated into the deep pores.

In order to avoid this, if the concentrations of the pyrrole monomer and the oxidant are halved, the number of repetitions of polymerization required for forming the polypyrrole layer is greatly increased from 2 to 3 times. In the form, such a situation does not occur.

(Embodiment 11) In this embodiment, instead of ethanol in Embodiment 10, methanol (A), n-propanol (B), ethylene glycol (C), propylene glycol (D), glycerin are used. Completing each of the 10 capacitor elements configured in the same manner as in Embodiment 10 except using (E),
The capacity at 1 kHz, the loss coefficient, and the impedance at 400 kHz were measured, and the rate of change in capacity and the loss coefficient after a load heat resistance test performed by applying 10 V at 125 ° C. were measured. (Table 2)
It was shown to.

As can be seen from Table 2, in the present embodiment as well, the polymerization rate was moderately delayed by adding methanol, n-propanol, ethylene glycol, propylene glycol and glycerin to the polymerization medium, Further, the action of the sulfonic acid type surfactant improves the permeability into the sintered body, which facilitates the formation of the polypyrrole layer even in the etching pits or in the deep pores of the sintered body. A conductive layer made of polypyrrole doped with alkylnaphthalene sulfonic acid partially substituted with divalent sulfate ions is formed.

The electrical conductivity and thermal stability of this polypyrrole are higher than those when doped with sulfate ions only.

As a result, it is possible to obtain a capacitor having a high capacity achievement rate, a low loss, a high frequency impedance characteristic, and a high heat resistance.

(Embodiment 12) This embodiment is the same as Embodiment 10 except that 1.7 g of sodium dodecylbenzene sulfonate is used instead of sodium alkylnaphthalene sulfonate in Embodiment 10. Completing the 10 capacitor elements configured as above, the capacitance at 1 kHz, loss factor, and 400 kH
Measure the impedance at z
The rate of change in capacity and the loss coefficient after the load heat resistance test conducted by applying 10 V at 0 ° C. were measured, and the average values thereof are shown in (Table 2) above.

As can be seen from Table 2, in the present embodiment as well, the addition of ethanol to the polymerization medium suppresses the polymerization reaction rate and the action of the surfactant sodium dodecylbenzenesulfone. In this way, the permeability into the sintered body is improved, and a conductive layer made of polypyrrole doped with the monovalent anion, dodecylbenzenesulfonic acid, partially substituted with the divalent sulfate ion is formed. .

The electrical conductivity and thermal stability of this polypyrrole are higher than those when doped with sulfate ions only.

As a result, a capacitor having a high capacity achievement rate, a low loss, a high frequency impedance characteristic, and a high heat resistance can be obtained.

(Embodiment 13) In this embodiment, ten tantalum sintered bodies of the tenth embodiment are used under the same conditions as the tenth embodiment except that the following etched aluminum foil electrodes are used. Capacitor was completed and the same characteristic evaluation was performed. The results are shown in (Table 2) above.

A specific method for producing an aluminum electrode foil is as follows. First, a polyimide tape having a width of 1 mm is applied to both sides of a 4 × 10 mm aluminum etched foil so as to be divided into 3 mm and 6 mm portions.

Next, aluminum etched foil 4 × 3 m
The anode lead of m part was attached, and the 4 × 6 mm part of the aluminum etched foil was applied with 50% V at about 70 ° C. using an aqueous 3% ammonium adipate solution to form an oxide film dielectric layer by anodic oxidation.

When this structure was regarded as a capacitor and the capacity of the chemical conversion liquid was measured, it was 4.7 μF.

As can be seen from Table 2, in this embodiment also, the polymerization rate was moderately delayed by adding alcohol to the polymerization medium, and the sintering was performed by the action of the sulfonic acid type surfactant. Since the permeability into the body is improved, the formation of the polypyrrole layer is facilitated even in the etching pits or the deep portion of the pores of the sintered body.
A conductive layer made of polypyrrole doped with valence sulfate ions partially substituted is formed.

The electrical conductivity and thermal stability of this polypyrrole are higher than those when doped with sulfate ions only.

As a result, a capacitor having a high capacity achievement rate, a low loss, a high frequency impedance characteristic and a high heat resistance can be obtained.

(Embodiment 14) In the present embodiment, in the structure of Embodiment 13, the thickness of the aluminum smooth foil of 20 mm × 20 mm is not coated with the oxide film dielectric but is formed by spin coating so that the thickness is reduced to 0. Ten capacitors in total were manufactured under substantially the same conditions as in the thirteenth embodiment except that an electrode having a polyimide dielectric layer made of a polyimide thin film of 0.5 μm was used.

The same evaluation as in the thirteenth embodiment was carried out on these, and the results are shown in (Table 2) above.

As can be understood from this (Table 2), also in the present embodiment, the addition of alcohol to the polymerization medium moderately retards the polymerization rate, and the anionic surfactant is added to the polymerization solution. When added, a conductive layer made of polypyrrole doped with the monovalent anion, alkylnaphthalene sulfonate ion partially substituted with the divalent sulfate ion is formed.

The electrical conductivity of this polypyrrole is higher than that when it is doped with sulfate ions only.

As a result, a capacitor element having a low loss and a high frequency impedance characteristic can be obtained.

(Embodiment 15) This embodiment is the same as Embodiment 10 except that 0.1 mol / l of p-nitrophenol was added to the monomer solution in the structure of Embodiment 10. As a result, 10 capacitor elements were completed.

Capacity at 1 kHz, loss factor, and 4
The impedance at 00 kHz was measured, and the rate of change in capacity and the loss coefficient after a load heat resistance test performed by applying 10 V at 125 ° C. were measured, and their average values are shown in (Table 2) above.

As can be seen from (Table 2), also in this example, by adding alcohol to the polymerization medium, the polymerization reaction rate was suppressed and at the same time the sulfonic acid type surfactant acted to sinter. Penetration into the body is improved, and the monovalent anion, alkylnaphthalene sulfonate anion, is doped in a form in which the divalent sulfate ion is partially replaced, and the conductivity and the conductivity thereof are improved by the action of p-nitrophenol. A conductive layer made of polypyrrole having further improved stability is formed.

The electrical conductivity of this polypyrrole is higher than that in the case where only the sulfate ion and the alkylnaphthalene sulfonate acid anion are present, and the thermal stability is high.

With these, it is possible to obtain a capacitor element having a high capacity achievement rate, a low loss, an excellent high frequency impedance characteristic, and a high heat resistance.

(Embodiment 16) In the present embodiment, p-nitrophenol of Embodiment 15 is replaced by
Same as Embodiment 15 except that m-nitrophenol (A), p-cyanophenol (B), m-hydroxybenzoic acid (C), m-hydroxyphenol (D) and acetophenol (E) were added. Then, 10 capacitors were completed.

Capacity at 1 kHz, loss factor, and 4
The impedance at 00 kHz was measured, and the rate of change in capacity and the loss coefficient after a load heat resistance test performed by applying 10 V at 125 ° C. were measured, and their average values are shown in (Table 2) above.

As can be seen from (Table 2), the capacitor according to the present embodiment is moderately retarded in the polymerization rate by adding alcohol to the polymerization medium, and is further burned by the action of the sulfonic acid type surfactant. Since the permeability into the bonded body is improved, the formation of the polypyrrole layer is facilitated even in the etching pits or the deep pores of the sintered body, and the monovalent anion, alkylnaphthalene sulfonic acid, is divalent sulfate ion. A conductive layer made of doped polypyrrole is formed in such a manner that a part of it is replaced.

The electric conductivity of this polypyrrole is higher than that when it is doped with only sulfate ions, and the thermal stability is high.

As a result, it is possible to obtain a capacitor element having a high capacity achievement rate, low loss, high frequency impedance characteristics, and high heat resistance.

(Embodiment 17) This embodiment is the same as Embodiment 10 except that in Embodiment 10, cupric sulfate having the same concentration is used instead of ferric sulfate. Complete the 10 capacitor elements configured,
The capacity at 1 kHz, the loss coefficient, and the impedance at 400 kHz were measured, and the rate of change in capacity and the loss coefficient after a load heat resistance test performed by applying 10 V at 125 ° C. were measured. (Table 2)
It was shown to.

As described above, also in this embodiment,
By adding alcohol to the polymerization medium, the polymerization rate is moderately delayed, and since the penetration into the sintered body is improved by the action of the sulfonic acid type surfactant, in the etching pits or the deep pores of the sintered body. Also facilitates the formation of a polypyrrole layer, where monovalent anions,
A conductive layer made of polypyrrole doped with alkylnaphthalene sulfonic acid partially substituted with divalent sulfate ions is formed.

The electrical conductivity and thermal stability of this polypyrrole are higher than those when doped with sulfate ions only.

As a result, a capacitor having a high capacity achievement rate, a low loss, a high frequency impedance characteristic and a high heat resistance can be obtained.

(Embodiment 18) In this embodiment, the tantalum sintered body electrode in Embodiment 10 is immersed in a 30% aqueous solution of manganese nitrate to form 250
Ten capacitors were completed in the same manner as in Embodiment 10 except that the manganese dioxide layer was formed by thermal decomposition at ℃.

Capacity at 1 kHz, loss factor, and 4
The impedance at 00 kHz was measured, and the average value thereof was shown in the above (Table 2).

The leakage current was 2.5 nA when a rated voltage of 10 V was applied. On the other hand, the tenth embodiment
The leakage current of the capacitor under the same conditions obtained in 2.
It was 9 nA and showed extremely low leakage current characteristics almost equal to each other.

Further, when the leak current was measured by changing the applied voltage of both of them from 1 V to 16 V, it was shown that the logarithmic value of the leak current was proportional to the half power of the applied voltage.

However, the former has the gradient,
The tendency was 0.95, which is smaller than the latter value of 1.14.

This is an effect due to the inclusion of a manganese dioxide layer having a relatively low electric conductivity, and it can be expected to suppress a short circuit when a high voltage is applied.

On the other hand, as is clear from (Table 2), the increase of the loss factor due to the inclusion of the manganese dioxide layer is extremely slight.

It is considered that this is because the thickness of the formed manganese dioxide layer was extremely thin.

(Embodiment 19) In this embodiment, after forming the anodic oxide film on the electrode foil in Embodiment 13, a 12% aqueous solution of sodium permanganate is used to contain a pyrrole monomer and sodium alkylnaphthalene sulfonate. A capacitor was produced in the same manner as in Example 3 except that reduced manganese dioxide was formed in the solution.

Also in this case, as in the eighteenth embodiment, it was recognized that the rate of increase of the leakage current with respect to the applied voltage was lower than that of the polypyrrole layer alone.

In the first to nineteenth embodiments described above,
Although the case where sodium aromatic sulfonate is used as the surfactant has been described, other sulfonic acid type surfactants may be used, and other anionic type surfactants containing monovalent anions other than the sulfonic acid type. Can also be used.

Further, in the first to nineteenth embodiments, only the case where the alcohol concentration is 10% has been described, but polymerization is performed in a medium of a higher concentration or a lower concentration than this unless there is a substantial difference in the capacitor characteristics. You can also

However, when the alcohol concentration is extremely low, the reaction rate is almost the same as when the aqueous medium is used, while when the concentration is higher than necessary, the polymerization reaction takes a long time, and also economically. Not desirable.

Further, in Embodiments 1 to 19, only the sulfate ion is described as the polyvalent anion, but a transition metal polyvalent acid salt other than the sulfate salt is used so that other polyvalent anions are doped. You can also

Further, in Embodiments 1 to 19, only the case where iron (III) and copper (II) are used as the transition metals has been described, but other transitions having a redox potential capable of oxidizing other pyrroles. Metals can be used as well and the invention is not limited to that type.

Further, in Embodiments 1 to 19, only the case where pyrrole was used as the polymerizable monomer was described, but a derivative having a substituent can also be used.

Further, in Examples 1 to 3, 5 to 7, 10 to 13, and 15 to 17, only the case where the valve metals are aluminum and tantalum was described, but other zirconium, niobium, hafnium and titanium, and further those. It is also possible to use an intermetallic compound or the like.

Further, in the fourth and fourteenth embodiments, the case where polyimide is used as the polymer serving as the dielectric has been described, but a polymer material other than polyimide may be used as long as it is a polymer material capable of forming a thin film, The present invention is not limited to that type.

In the fourth and fourteenth embodiments, the case where a polyimide film serving as a dielectric is formed on an aluminum smooth foil by spin coating has been described. However, for example, a polyimide film provided by electrodeposition on an etched aluminum foil surface is used. The present invention can be applied as one electrode of a film capacitor made of a dielectric material, and the present invention is not limited to the method for forming the same.

[0199]

INDUSTRIAL APPLICABILITY As described above, the present invention relating to a capacitor uses a conductive layer composed of a pyrrole polymer containing a polyvalent anion and a monovalent anion as dopants, and has at least a capacitor provided facing each other. By constructing one of the electrodes, by introducing a dopant with a large molecular size, the electrical conductivity and thermal stability of the polymer are improved, so that a capacitor with excellent loss coefficient and impedance characteristics can be obtained, and heat resistance can be improved. It has a unique effect of improving the property.

If an anionic surfactant is used,
By the action, the permeability is improved and the capacity achievement rate can be improved.

Furthermore, by interposing a manganese dioxide layer between the dielectric and the conductive polymer, it is possible to improve the leakage current characteristics while keeping the loss coefficient small.

Then, the method for producing a capacitor of the present invention comprises a conductive polymer layer of a capacitor comprising a repeating unit of pyrrole or a derivative thereof and a conductive polymer layer containing a polyvalent anion and a monovalent anion as dopants. Is a method for manufacturing a capacitor having a chemical polymerization step of forming by chemical polymerization. Since polypyrrole is formed by chemical polymerization in a solution at room temperature, damage to the dielectric layer due to heat is prevented.

In the case where the dielectric layer is composed of a valve metal oxide film, it is required for each repeated pyrolysis treatment when the manganese oxide layer is formed by the conventional pyrolysis. Even if the repair chemical treatment is omitted, a solid electrolytic capacitor with low leakage current can be easily obtained.

The present invention relating to a further method for producing a capacitor comprises a conductive polymer layer containing pyrrole or a derivative thereof as a repeating unit in a mixed medium of water and alcohol, preferably containing an anionic surfactant. With a polyvalent acid salt of a transition metal as an oxidant, it has a chemical polymerization step to form by chemical polymerization. Since the polymerization rate is moderately delayed by the addition of alcohol, it does not reach the etching pits or the deep pores of the sintered body. The polypyrrole layer can be easily formed, and a capacitor having a high capacity achievement rate can be obtained with a small number of times of repeating polymerization.

Further, since the action of the surfactant improves the permeability, the capacity achievement rate is improved, and the electric conductivity and thermal stability of the polymer are improved by introducing a dopant having a large molecular size. A unique effect is obtained in that a capacitor having an excellent loss coefficient and impedance characteristics can be obtained, and at the same time, heat resistance can be improved.

Furthermore, by adding phenol or a phenol derivative, the electrical conductivity and thermal stability of polypyrrole can be further improved, the loss coefficient and impedance characteristics can be further improved, and a capacitor with superior heat resistance can be obtained. realizable.

Furthermore, by interposing the manganese dioxide layer between the dielectric and the conductive polymer, there is a unique effect that leakage current characteristics are improved while keeping the loss coefficient small.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of surfactant added to polypyrrole, the electrical conductivity, and the yield in the first embodiment of the present invention.

FIG. 2 is a diagram showing another relationship between the amount of surfactant added to the polypyrrole, the electrical conductivity, and the yield in the first embodiment.

FIG. 3 is a graph showing the relationship between the amount of ethanol added to the polypyrrole, the electrical conductivity, and the yield in the tenth embodiment.

FIG. 4 is a diagram showing the relationship between the amount of surfactant added to the polypyrrole, the electrical conductivity, and the yield in the tenth embodiment.

FIG. 5 is a diagram showing the relationship between the presence or absence of a surfactant added to polypyrrole and the stability of electrical conductivity in the tenth embodiment.

Front page continued (72) Inventor Matsue Yasue 3-10-1 Higashisanda, Tama-ku, Kawasaki, Kanagawa Matsushita Giken Co., Ltd. (72) Inventor Hiroshi Shimada 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co. Inside the company (72) Inventor Chiharu Hayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (22)

[Claims] 1. A pair of electrodes provided facing each other, a dielectric layer provided between the electrodes, and at least one of the electrodes, wherein a pyrrole or a derivative thereof is used as a repeating unit, and a polyvalent anion and a monovalent anion are used. And a conductive polymer layer containing a valent anion as a dopant. 2. The capacitor according to claim 1, wherein the polyvalent anion is a sulfate group. 3. The capacitor according to claim 1, wherein the monovalent anion is a sulfonic acid group. 4. The capacitor according to claim 3, wherein the sulfonic acid group is dissociated from the anionic surfactant. 5. The capacitor according to claim 1, wherein the dielectric layer is an oxide of a valve metal forming one of the electrodes. 6. The capacitor according to claim 5, wherein the valve metal is aluminum or tantalum. 7. The capacitor according to claim 1, wherein the dielectric layer is a polymer film. 8. The polymer film is a polyimide film.
The listed capacitors. 9. The capacitor according to claim 1, further comprising a manganese dioxide layer provided between the dielectric and the conductive polymer layer. 10. A step of disposing a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a step of forming a dielectric layer between the electrodes, wherein pyrrole or a derivative thereof is used as a repeating unit, and A method for producing a capacitor, comprising a chemical polymerization step of forming a conductive polymer layer of a capacitor having a polyvalent anion and a conductive polymer layer containing a monovalent anion as a dopant by chemical polymerization. 11. A step of disposing a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a step of forming a dielectric layer between the electrodes, wherein at least one of the electrodes comprises pyrrole or a derivative thereof as a repeating unit, and Method for producing a capacitor having a chemical polymerization step of forming a conductive polymer layer of a capacitor having a polyvalent anion and a conductive polymer layer containing a monovalent anion as a dopant by chemical polymerization in a medium containing water and alcohol . 12. The method for producing a capacitor according to claim 11, wherein the alcohol is one selected from methanol, ethanol, propanol, ethylene glycol, propylene glycol or glycerin or a mixture thereof. 13. The chemical polymerization step forms a conductive polymer layer using a solution containing pyrrole or a derivative thereof, ferric sulfate and an anionic surfactant.
3. The method for manufacturing a capacitor as described in 2. 14. The method for producing a capacitor according to claim 10, wherein an anionic surfactant containing an anion having a sulfonic acid group is used. 15. The method of manufacturing a capacitor according to claim 10, wherein the dielectric forming step forms the dielectric by anodic oxidation of the valve metal. 16. The method of manufacturing a capacitor according to claim 15, wherein the valve metal forming one of the electrodes is aluminum or tantalum. 17. The method of manufacturing a capacitor according to claim 10, wherein in the dielectric forming step, the dielectric is formed using a polymer thin film. 18. The polymer as claimed in claim 17, which is a polyimide.
A method for manufacturing the described capacitor. 19. The method for producing a capacitor according to claim 10, wherein in the chemical polymerization step, the chemical polymerization is further performed using a solution containing phenol or a derivative thereof. 20. The method for producing a capacitor according to claim 19, wherein the phenol derivative is nitrophenol, cyanophenol, hydroxybenzoic acid, hydroxyphenol or acetophenol, or a combination thereof. 21. The method for producing a capacitor according to claim 10, further comprising a manganese dioxide layer forming step of thermally decomposing a manganese dioxide layer between the dielectric and the conductive polymer layer. . 22. The method for producing a capacitor according to claim 10, wherein the manganese dioxide layer forming step forms a manganese dioxide layer by reducing permanganate.