JP2000021687A - Capacitor and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve high-frequency characteristics of a capacitor which uses a conductive composition (PEDTT) obtained by polymerizing 3,4-ethylene- dithiathiophene for at least one of facing electrodes for facilitating fabrication of such a capacitor easy. SOLUTION: This method for manufacturing a capacitor, where a conductive high molecule layer made by repeating a thiophene derivative as a unit, is formed by applying a solution dissolved with conductive high molecues or polymerization. Further superior characteristics can be obtained for the capacitor, by complexing the PEDTT with polypyrrole(PPy) or polyethylene dioxythiophene (PEDOT). If another PEDTT layer is formed by applying a solution of PEDTT on the composite conductive layer, the number of repeated polymerizations required for the formation of the electrolyte can be reduced, thus simplifying a process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor and a method of manufacturing the same, and more particularly, to a small and large-capacity capacitor excellent in capacitor characteristics such as frequency characteristics and withstand voltage characteristics and a method of manufacturing the same.

[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 range include plastic capacitors, mica capacitors, and multilayer ceramic capacitors. However, these capacitors have a large shape and are difficult to increase in capacitance.

On the other hand, as capacitors having a large capacity, there are electrolytic capacitors such as an aluminum dry electrolytic capacitor and an aluminum or tantalum solid electrolytic capacitor.

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

For example, in an aluminum dry capacitor, an etched anode and cathode aluminum foil are wound through a separator, and the separator is impregnated with a liquid electrolyte for use.

[0007] This liquid electrolyte has a problem that loss is large and impedance frequency characteristics and temperature characteristics are remarkably inferior due to ionic conductivity and large specific resistance.

In addition, there is a problem that liquid leakage, evaporation, and the like are inevitable, and the capacity is reduced and the loss is increased with time.

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

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

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

Further, there has been proposed a solid electrolytic capacitor formed by forming a conductive polymer having a substituent at the 3- and 4-positions, polythiophene, by chemical polymerization (Japanese Patent Publication No. 2-15 / 1990).
611).

Further, after forming a dielectric comprising an electrodeposited polyimide thin film on an etched aluminum foil, a conductive polymer layer is sequentially formed by chemical polymerization and electrolytic polymerization to form a large-capacity film capacitor serving as an electrode. (Proceedings of the 58th Annual Meeting of the Institute of Electrical Chemistry, pp. 251-252 (1991)).

[0014]

However, when an electropolymerized polymer is formed via a conductive pyrolytic metal oxide such as manganese oxide, the dielectric film is damaged by heat. In order to obtain a capacitor with a high withstand voltage, it is necessary to carry out chemical formation again before electrolytic polymerization and to repair the same, which has a problem that the process is further complicated.

Further, in a tantalum solid electrolytic capacitor, an electrolyte composed of manganese oxide is formed by repeating thermal decomposition, and a chemical conversion is required each time to repair the generated film damage, and the process becomes more complicated. There was a problem that.

In addition, when a conductive polymer layer is formed by chemical polymerization using polypyrrole, the polymerization rate is high at around room temperature, so that the polymer is polymerized while penetrating deep into the etched aluminum foil and the pores of the tantalum sintered body. As a result, the etch pits and pores of the sintered body were partially blocked, and it was difficult to form a conductive polymer layer having a high filling factor.

This problem can be solved by lowering the polymerization temperature. However, when water is used as a medium, there is a limit because water freezes at around 0 degrees Celsius.

This problem can be solved by lowering the concentration of the pyrrole monomer, but on the other hand, a new problem arises in that the number of times of polymerization required for coating increases.

Further, when the polypyrrole layer and the polymer layer of 3,4-ethylenedioxythiophene (polyethylenedioxythiophene) are formed by chemical polymerization, a powdery polymer is obtained, and the surface of the capacitor electrode, Above all, there was also a problem that the coatability of the edge portion was poor, and that a long time was required for polymerization for complete coating.

In the case of electrolytically polymerized polypyrrole, such a problem does not occur because a film-like polymer is obtained, but a film having a high coverage cannot be formed unless conductivity is imparted to the dielectric surface. There were challenges.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and provides a simple method for obtaining a solid electrolytic capacitor having a high capacity and a high heat and moisture resistance. Another object of the present invention is to easily obtain a film capacitor having high heat, humidity and resistance.

[0022]

According to the present invention, a pair of electrodes provided to face each other, a dielectric layer provided between the electrodes, and at least one of the electrodes, 3,4-ethylenedithia The capacitor has a conductive polymer single layer containing thiophene as a repeating unit or a laminated conductive polymer layer with pyrrole or a conductive polymer layer containing 3,4-ethylenedioxythiophene as a repeating unit.

C. Wang et al., `` Poly (3,4-ethylenedithi
athiophen). A New Soluble Condutive Polythiophen D
erivative ", Chem. Mater., 7 (1995) 58-6.
On page 8, it is disclosed that polyethylene dithiathiophene having 3,4 ethylenedithiathiophene as a repeating unit can be synthesized from the above monomers by chemical polymerization or electrolytic polymerization.

Furthermore, it is described that this conductive polymer is soluble in solvents such as N-methylpyrrolidone, tetrahydrofuran and chloroform.

The conductive polymer layer containing 3,4 ethylenedithiathiophene as a repeating unit can be formed by applying a solution containing the conductive polymer or by in-situ polymerization using chemical polymerization or electrolytic polymerization. The forming method for forming is preferable.

Further, according to the present invention, a pair of electrodes provided to face each other, a dielectric layer provided between the electrodes, and at least one of the electrodes comprising 3,4-ethylenedithiathiophene as a repeating unit A conductive polymer layer comprising:
A laminated conductive polymer layer composed of a conductive polymer layer containing pyrrole or a derivative thereof as a repeating unit, or a laminated conductive layer composed of a conductive polymer layer further containing a 3,4-ethylenedithiathiophene derivative as a repeating unit. It has a capacitor.

Further, the polymerization of polypyrrole or polyethylenedioxythiophene is carried out by using P-nitrophenol, P-cyanophenol, m-hydroxybenzoic acid,
It can also be carried out in an aqueous medium containing phenol derivatives such as m-hydroxyphenol and m-nitrophenol.

In the thiophene derivative, this promotes the polymerization reaction, while in the case of a conductive polymer containing pyrrole and its derivative, an improvement in electric conductivity is observed.

The outermost conductive polymer layer containing a 3,4 ethylenedithiathiophene derivative as a repeating unit is:
In particular, when polypyrrole or polyethylenedioxythiophene in the inner layer is formed by chemical polymerization, a production method using solution impregnation is preferable.

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

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1, wherein a pair of electrodes provided to face each other, a dielectric layer provided between the electrodes, and at least one of the electrodes has three or four electrodes.
This is a capacitor having a conductive polymer layer composed of a conductive polymer layer containing ethylenedithiathiophene as a repeating unit.

As described above, in the capacitor in which the dielectric is composed of the valve metal oxide film, the conductive polymer functions as an electrolyte also serving as a true cathode, while in the capacitor in which it is composed of a polymer thin film, It functions as a simple electrode.

Furthermore, the invention of claim 2 provides a laminated conductive high layer comprising a conductive polymer layer containing 3,4 ethylenedithiathiophene as a repeating unit and a conductive polymer layer containing pyrrole or a derivative thereof as a repeating unit. This is a capacitor having a molecular layer.

Here, the laminated conductive polymer layer is provided so as to be adjacent to the second conductive polymer layer on the side opposite to the first conductive polymer layer. And a configuration including a third conductive polymer layer containing 3,4 ethylenedithiathiophene as a repeating unit.

Further, the dielectric layer may be an oxide of a valve metal constituting one of the electrodes.

In this case, it is preferable that the valve metal is aluminum or tantalum.

Further, as described in claim 6, the dielectric layer may be a polymer film, and in this case, as in claim 7, the polymer film is preferably a polyimide film. is there.

On the other hand, as an example of a specific method of manufacturing a capacitor, a step of arranging a pair of electrodes facing each other and a step of forming a dielectric layer between the electrodes are described. Forming a conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit in at least one of the electrodes by applying a solution obtained by dissolving the polymer. is there.

As described above, since the conductive polymer layer is formed by the coating method, damage to the dielectric layer due to heat can be prevented.

The method of manufacturing a capacitor, which is basically the same as that of the first embodiment, includes a step of arranging a pair of electrodes facing each other, and a step of arranging a dielectric between the electrodes. Production of a capacitor having a dielectric layer forming step of forming a layer and a chemical polymerization step of forming, by chemical polymerization, a conductive polymer layer containing 3,4 ethylenedithiothiophene as a repeating unit in at least one of the electrodes. Is the way.

Further, as described in claim 11, an electrolytic polymerization step can be used instead of the chemical polymerization step.

In another specific method for manufacturing a capacitor, a step of arranging a pair of electrodes facing each other and a step of forming a dielectric layer between the electrodes are described. Forming a conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit on at least one of the electrodes by coating, and further containing pyrrole or 3,4-ethylenedioxythiophene as a repeating unit This is a method for manufacturing a capacitor having a chemical polymerization step of forming a conductive polymer layer made of a conductive polymer layer by chemical polymerization.

The conductive polymer containing 3,4-ethylenedithiathiophene as a repeating unit has an electric conductivity of 10
Although it is on the order of -1 Scm-1, the electric conductivity of the conductive polymer composed of a conductive polymer layer containing pyrrole or 3,4-ethylenedioxythiophene as a repeating unit is on the order of 101 Scm-1. The frequency characteristics can be expected to be improved as compared with the case where the former is used in a single layer.

Further, a conductive polymer layer comprising a conductive polymer layer further containing pyrrole or 3,4-ethylenedioxythiophene as a repeating unit can be formed by electrolytic polymerization. .

In the case of electrolytic polymerization, since a conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit exists, the conductive polymer layer can be formed smoothly through the conductive polymer layer.

As described later, non-toxic and non-flammable water can be used as a medium for forming a conductive polymer layer containing pyrrole or 3,4-ethylenedioxythiophene as a repeating unit. Can be easily constructed and mass production can be facilitated.

Further, as described in claim 14, a conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit may be formed by chemical polymerization. It can also be carried out by polymerization.

In this case, it is necessary to form a thermally decomposed manganese dioxide or reduced manganese dioxide layer on the surface of the dielectric material and to provide conductivity in advance.

Furthermore, as described in claim 17, 3, 4
A capacitor can also be manufactured by forming a conductive polymer layer containing ethylene-dithiathiophene as a repeating unit and forming a third conductive polymer layer on the second conductive polymer.

For example, in the case of chemical polymerization, a powdery polymer film is formed, and short-circuit failure due to penetration of colloidal graphite, which is a cathode constituent material, is likely to occur.
It is important to prevent this.

For this reason, it has often been carried out to form a thick polymer layer by increasing the number of forming treatments.
As described above, the process can be simplified.

Further, in the chemical polymerization step of the second conductive polymer layer, a medium to which a phenol derivative or a nitrobenzene derivative is added can be used.

By adding a phenol derivative or a nitrobenzene derivative, the electric conductivity and the stability of the conductive polymer obtained from the thiophene derivative and pyrrole are further improved.

This is because the phenolic compound is not incorporated as a dopant in the amphoteric conductive polymer,
This is thought to be due to the formation of a conductive polymer with a high degree of regularity and therefore a conjugated length.As a result, the initial characteristics and stability of capacitors using polypyrrole obtained from a polymerization system to which a phenolic derivative has been added Sex is further improved.

In the case of 3,4-ethylenedioxythiophene, the mechanism is unknown, but these additives can improve the environmental stability and are effective for improving the heat and moisture resistance of the capacitor. It is.

Here, as described in claim 19, the phenol derivative is nitrophenol, cyanophenol,
Suitably, it is hydroxybenzoic acid, hydroxyphenol or acetophenol, or a combination thereof.

In this case, it is preferable that the nitrobenzene derivative is nitrobenzoic acid, nitrobenzyl alcohol or a combination thereof. Phenol, cyanophenol, hydroxybenzoic acid, hydroxyphenol or acetophenol,
Or a combination thereof.

Further, in the electrolytic polymerization step of the second conductive polymer layer, a medium to which a phenol derivative or a nitrobenzene derivative has been added can be used.

Here, as described in claim 22, the phenol derivative is nitrophenol, cyanophenol,
Suitably, it is hydroxybenzoic acid, hydroxyphenol or acetophenol, or a combination thereof.

In this case, it is preferable that the nitrobenzene derivative is nitrobenzoic acid, nitrobenzyl alcohol or a combination thereof.

Further, as described in claim 24, the dielectric formation step can be performed by anodizing the valve metal.

Here, aluminum or tantalum can be used as the valve metal.

Further, as described in claim 26, polymer spin coating can be used in the dielectric formation step.

Here, as the polymer material, polyimide is preferably used as the polymer material.

Each embodiment of the present invention will be described below in detail with reference to the drawings. (Embodiment 1) FIG. 1 is a conceptual diagram of a capacitor according to the present embodiment.

In this embodiment, first, 2 × 1.
A 4 × 0.9 mm ³ tantalum sintered body (anode valve metal 1) was used by applying a solution of 5 ml of phosphoric acid in 1000 ml of water at 40 ° C. at about 90 ° C., and anodized to form an oxide dielectric film. (Dielectric 3) was formed.

This configuration was regarded as a capacitor, and the capacity in the chemical conversion solution was measured to be 18.0 μF.

Further, using this configuration, the poly (3, 4)
-Ethylenedithiathiophene) (PEDTT) was immersed in an N-methylpyrrolidone solution for 5 minutes, and then immersed in a 0.1 M tetrabutylammonium perchlorate solution for 10 minutes. This operation was repeated until the surface was coated with PEDTT. The number of repetitions required for coating was 11 times.

Here, PEDDT conforms to C.I. Wang and others,
"Poly (3,4-ethylenedithiathiophen). A New Soluble
Condutive Polythiophen Derivative ", Chem. Mater.,
7 (1995), pp. 58-68.

Next, on the tantalum sintered body having the PEDTT layer (conductive polymer layer 4) formed thereon, a cathode 5 is formed with a carbon layer and a silver paint layer, and a cathode lead is mounted thereon. Thus, a total of 10 capacitor elements were obtained.

The number of coating repetitions required for coating was 12 times. Further, the element was packaged using an epoxy resin, and an aging treatment at 13 ° C. was applied at 125 ° C. to complete a capacitor.

With respect to these ten devices, the capacitance at 1 kHz, the loss coefficient, and the impedance at 400 kHz were measured, and the average values were shown in the following (Table 1).

[0073]

[Table 1]

(Comparative Example 1) Next, for comparison, Comparative Example 1
In place of PEDTT, immersion in a 30% aqueous solution of manganese nitrate and pyrolysis at 250 ° C. to form manganese dioxide as an electrolyte were performed under the same conditions as in the first embodiment.
Completed capacitors.

As with the first embodiment, the capacity, the loss coefficient, and the
The impedance at 00 kHz was measured, and the average value was shown in the above (Table 1).

Examination of the results of the first embodiment and this comparative example shows that the loss coefficient and the impedance are improved when the PEDTT is used.

In this comparative example, in order to reduce the leakage current, a chemical conversion treatment for repairing the dielectric film was required every time the manganese nitrate was thermally decomposed. According to this, since a heat treatment step was not performed, a leakage current equivalent to that of a capacitor using manganese dioxide as an electrolyte could be obtained without repair formation.

From the above, it has been found that a capacitor excellent in capacitor characteristics can be easily manufactured by employing PEDTT as an electrolyte.

(Embodiment 2) In this embodiment, the same conditions as in Embodiment 1 are used except that an etched aluminum foil electrode is used instead of the tantalum sintered body of Embodiment 1.
Completed 0 capacitors and evaluated the same characteristics.
The results are shown in the above (Table 1).

Here, a specific fabrication of an etched aluminum electrode foil was performed as follows. First, 4 × 10mm
A 1 mm wide polyimide tape was stuck on both sides so as to partition the aluminum-etched foil of No. ² into portions of 3 mm and 6 mm.

Next, 4 × 3 m of aluminum etched foil
Install the anode lead of m ² parts (anode valve metal 1),
3% of 4x6mm ² part of aluminum etched foil
Using an aqueous solution of ammonium adipate, at about 70 ° C., 50
V was applied to form an oxide film dielectric layer (dielectric 3) by anodic oxidation.

Here, this configuration is regarded as a capacitor,
When the volume in the chemical conversion solution was measured, it was 4.92 μF.

The number of repetitions of the immersion treatment required for coating with PEDTT was 12 times. With respect to these ten devices, the capacitance at 1 kHz, the loss coefficient, and the impedance at 400 kHz were measured in the same manner as in the first embodiment, and their average values were shown in Table 1 above.

The reason why the capacitor has a higher loss coefficient and a smaller impedance than that estimated from the capacitance ratio as compared with the capacitor of the first embodiment is based on the difference between the electrode structures of the sintered body and the etched foil. I can say.

Also in the present embodiment, a high capacity achievement rate,
A capacitor excellent in low loss and high frequency impedance characteristics could be obtained efficiently.

(Embodiment 3) FIG. 2 is a conceptual diagram of a capacitor according to the present embodiment. In the present embodiment, in the configuration of the second embodiment, instead of the etched aluminum foil, a 20 mm × 20 mm aluminum smooth foil (electrode 2
a), an electrode having a polyimide dielectric layer (dielectric layer 3) formed of a 0.5 μm-thick polyimide thin film formed on one surface by spin coating instead of additionally forming an oxide film dielectric is used. A total of ten capacitors were manufactured under substantially the same conditions as in Embodiment 2 except for the above.

The number of repetitions of the immersion treatment required for coating with PEDTT was 12 times. These were evaluated in the same manner as in Embodiment 2, and the results are shown in the above (Table 1).

By forming the PEDTT layer (conductive polymer layer 4) on the smooth foil side on which the dielectric film has been formed, the PEDTT layer is in good contact with the smooth foil on which the dielectric film has been formed, and the capacity achievement rate is reduced. A high capacitor could be obtained.

Although the description has been given of the case where polyimide is used as the polymer serving as the dielectric, any material other than polyimide can be used as long as it is a polymer material of the dielectric capable of forming a thin film.

Although the case where the polyimide film serving as a dielectric is formed on the smooth aluminum foil by spin coating has been described, the polyimide film may be formed on the surface of the etched aluminum foil by, for example, electrodeposition.

(Embodiment 4) This embodiment is the same as Embodiment 1 except that PEDTT is formed by chemical polymerization instead of applying the PEDTT solution to form an electrolyte. Thus, ten capacitor elements configured as described above were completed.

In the chemical polymerization, the capacitor element is alternately immersed in a 100 ml solution of acetonitrile containing 0.005 mol of 3,4-ethylenedioxythiophene (EDTT) and a 100 ml solution of acetonitrile containing 0.005 mol of ferric chloride. And a PEDTT layer.

The number of repetitions of the immersion treatment required for coating with PEDTT was 13 times. With respect to these ten devices, the capacitance at 1 kHz, the loss coefficient, and the impedance at 400 kHz were measured in the same manner as in the first embodiment, and their average values were shown in Table 1 above.

As understood from Table 1, it was found that the same capacitor characteristics as in the first embodiment can be realized in the present embodiment.

As described above, also in the present embodiment, a capacitor having excellent high capacity achievement ratio, low loss, and excellent high-frequency impedance characteristics can be efficiently obtained.

(Embodiment 5) This embodiment is the same as Embodiment 2 except that PEDTT is formed by electrolytic polymerization instead of applying the PEDTT solution to form an electrolyte. Thus, ten capacitor elements configured as described above were completed.

The electrolytic polymerization was carried out by using an acetonitrile solution containing 0.1 M of EDTT and 0.1 M of tetrabutylammonium perchlorate and applying 3 V.

After forming the dielectric film, the etched aluminum foil was immersed in a 5% manganese nitrate solution and heated to 250 ° C. to form a thin manganese dioxide layer.

The polymerization was carried out by generating an electric power from a polymerization initiating electrode provided near the surface through the conductive layer.

As in the first embodiment, the capacitance, the loss coefficient, and the
The impedance at 00 kHz was measured, and the average value was shown in the above (Table 1).

As can be understood from Table 1, it is understood that the present embodiment can also realize the same capacitor characteristics as in the second embodiment.

As described above, also in this embodiment, a capacitor having a high capacity achievement ratio, a low loss and excellent high-frequency impedance characteristics can be efficiently obtained.

(Embodiment 6) FIG. 3 is a conceptual diagram of a capacitor according to the present embodiment.

In the present embodiment, the structure of the first embodiment is different from that of the first embodiment in that a laminated conductive layer made of PEDTT and polypyrrole (PPy) is formed instead of forming an electrolyte only with PEDTT. 1 in the same way as
Zero capacitor elements were completed.

The PEDTT is formed by a single immersion treatment in the same manner as described in Embodiment 1, and then the tantalum on which the PEDTT layer (the first conductive polymer layer 4) is formed as described above. 0.75m of pyrrole monomer on the sintered body
ol / l and 0.75% by weight of sodium alkylnaphthalenesulfonate (average molecular weight: 338) in a monomer aqueous solution at 25 ° C. for 2 minutes, and then ferric sulfate 0.1 mol
It was immersed in an oxidizing agent solution containing 1 / l at room temperature for 10 minutes.

This process is repeated until the surface is covered with PPy, and a carbon layer and a silver paint are formed on the tantalum sintered body (anode valve metal 1) on which PPy (second conductive polymer layer 6) is formed. The cathode 5 was formed as a layer in the same manner as in the first embodiment to obtain a total of 10 capacitor elements.

The number of repetitions of the immersion treatment required for coating with PPy was nine. For these ten elements, the capacitance at 1 kHz, the loss factor, and 400 kHz
The impedance at each z was measured, and their average values are shown in the following (Table 1).

When a PPy layer is formed in situ by chemical polymerization, it is extremely difficult to fill the pore structure of the sintered body because the polymerization rate is high.

This can be realized, for example, by lowering the monomer concentration and the oxidizing agent concentration, or by lowering the polymerization temperature. However, the capacitor can be easily formed because the required number of repetitions of the treatment increases or the process control becomes difficult. There is a problem that can not be obtained.

First, by forming a conductive polymer layer deep in the pore structure using a PEDTT solution,
Even if the process for forming the Py layer was simplified, a capacitor with a high capacity achievement rate could be obtained.

Furthermore, by laminating a PPy layer having an electric conductivity two orders of magnitude higher than that of PEDTT, the resistance of the electrolyte could be reduced, and the loss coefficient and the impedance could be further reduced.

Although an aqueous medium was used for forming the PPy layer, other organic solvents can be used, and oxidizing agents and additives other than those used in the present embodiment can also be used.

(Embodiment 7) In this embodiment, in the configuration of Embodiment 6, PEDTT is used instead of PPy.
And poly (3,4-ethylenedioxythiophene) (PE
Ten capacitor elements were completed in the same manner as in Embodiment 6, except that a laminated conductive layer made of DOT) was formed.

The PEDTT is formed by a single immersion process in the same manner as described in Embodiment 1, and then the tantalum having the PEDTT layer (first conductive polymer layer 4) formed thereon On the sintered body (anode valve metal 1), 3,4-ethylenedioxythiophene monomer (EDOT) 0.1
mol / l and 4% by weight of sodium triisopropylnaphthalenesulfonate (average molecular weight: 338) at 65 ° C.
Immersed in a monomer aqueous solution for 2 minutes, then ferric sulfate 0.1m
It was immersed in an oxidizing agent solution containing 65 ol / l at 65 ° C. for 100 minutes.

This process is repeated until the surface is covered with PPy, and the carbon layer and the silver paint are placed on the tantalum sintered body (anode valve metal 1) on which PPy (second conductive polymer layer 6) is formed. The cathode 5 was formed as a layer in the same manner as in the first embodiment to obtain a total of 10 capacitor elements.

The number of repetitions of the immersion treatment required for coating with PEDOT was 10 times. For these 10 elements, the capacitance at 1 kHz, the loss factor, and 40
The impedance at 0 kHz was measured, and the average value was shown in the following (Table 1).

When a PEDOT layer is formed in situ by chemical polymerization, it is extremely difficult to fill the pore structure of the sintered body.

This can be realized, for example, by lowering the monomer concentration and the oxidizing agent concentration, or by lowering the polymerization temperature. There is a problem that can not be obtained.

First, by forming a conductive polymer layer deep in the pore structure using a PEDTT solution,
Even if the process for forming the Py layer was simplified, a capacitor with a high capacity achievement rate could be obtained.

Furthermore, by laminating a PEDOT layer having an electric conductivity two orders of magnitude higher than that of PEDTT, the resistance of the electrolyte could be reduced, and the loss coefficient and the impedance could be further reduced.

Although an aqueous medium was used for forming the PEDOT layer,
Other organic solvents can be used, and oxidizing agents,
Additives other than those used in the present embodiment can also be used.

(Embodiment 8) In this embodiment, PEDTT is replaced with PED in the configuration of Embodiment 2.
Ten capacitor elements were completed in the same manner as in Embodiment 2, except that a laminated conductive layer made of TT and electrolytic polymerization PPy was formed.

The electrolytic polymerization was carried out by using an aqueous solution containing 0.25 M of a pyrrole monomer and 0.1 M of a supporting electrolyte, sodium triisopropylnaphthalenesulfonate, at a voltage of 3 V.

The same evaluation as in Embodiment 2 was performed for these, and the results are shown in the above (Table 1).

As can be understood from Table 1, it is understood that a capacitor having excellent characteristics can be realized also in the present embodiment.

The advantages of the loss coefficient and the impedance characteristic over those obtained in the second embodiment are due to the fact that electrolytic polymerization PPy having two orders of magnitude higher electric conductivity is used as an electrolyte.

According to the present embodiment, since the conductive layer that mediates the growth of the electrolytically polymerized film can be formed of PEDTT,
The heat treatment step required for the formation of the pyrolytic manganese dioxide layer is not required, and there is an advantage that the step can be simplified.

As described above, also in this embodiment, a capacitor having a high capacity achievement ratio, a low loss and an excellent high-frequency impedance characteristic can be efficiently obtained.

Similar results were obtained when PEDOT was used after electrolytic polymerization instead of PPy.

(Embodiment 9) FIG. 4 is a conceptual diagram of a capacitor according to the present embodiment. In the present embodiment, in the configuration of the sixth embodiment, PEDTT, PPy, and PED
Ten capacitor elements were completed in the same manner as in Embodiment 6, except that a laminated conductive layer made of TT was formed.

PEDTT (first conductive polymer layer 4)
Is formed by one dipping treatment in the same manner as described in the first embodiment, and then the chemically polymerized PPy (the second conductive polymer layer 6) is formed in the same manner as described in the sixth embodiment. Formed.

The number of immersion treatments required for forming PPy is 5
It was times. In this state, the surface was not completely covered with PPy.

Thereafter, a PEDTT layer (third conductive polymer layer 7) was formed on the surface in the same manner as in the first embodiment.

The number of applications required for this formation was one. With respect to these ten devices, the capacitance at 1 kHz, the loss factor, and the impedance at 400 kHz were measured, and the average values thereof were shown in the following (Table 1). When the PPy layer is formed in situ by chemical polymerization, there is a problem in coverage of the surface, particularly the edge portion,
In order to compensate for this, there has been a problem that the number of immersion treatments required for forming the conductive polymer layer increases.

According to the present embodiment, by forming the outermost conductive polymer layer by applying the PEDTT solution, the number of times of immersion treatment for forming the electrolyte can be reduced.

As described above, also in the present embodiment, it was possible to efficiently obtain a capacitor having a high capacity achievement ratio, low loss, and excellent high-frequency impedance characteristics.

In this embodiment, only the case where the chemically polymerized PPy is used for the second conductive layer has been described. However, the same effect was obtained when the chemically polymerized PEDOT was used.

(Embodiment 10) In this embodiment, the electrolytic polymerization solution described in Embodiment 8 is further added with 0.075 M
Ten capacitors were completed in the same manner as in Embodiment 8, except that an electrolytic polymerization solution having a composition to which p-nitrophenol (pNPh) was added was used.

For each of these ten devices, the capacitance at 1 kHz, the loss coefficient, and the impedance at 400 kHz were measured, and the average values were shown in Table 1 below.

The inventors have found that PPy obtained by electrolytic polymerization or chemical polymerization in a system in which pNPh coexists has improved electric conductivity and environmental stability.

It is considered that this is due to the formation of PPy having a highly regular skeleton structure by the action of the nitro group of the electron donating substituent.

And, as understood from (Table 1),
It has been found that the capacitor of the present embodiment is more excellent in loss count and impedance than the capacitor of the eighth embodiment.

Since the environmental stability of PPy thus obtained is high, it was easily expected that this capacitor was excellent also in heat resistance and moisture resistance.

(Embodiment 11) This embodiment is different from the oxidizing agent solution described in Embodiment 7 in that an oxidizing agent solution having a composition obtained by further adding 0.075 M p-nitrophenol (pNPh) is used. , 10 in the same manner as in the seventh embodiment.
Completed capacitors.

With respect to these ten devices, the capacitance at 1 kHz, the loss factor, and the impedance at 400 kHz were measured, and the average values were shown in the following (Table 1).

The number of repetitions of the immersion treatment required for coating with PEDOT was seven. The present inventors have found that in a system in which pNPh coexists, the chemical polymerization rate increases, and it is considered that the effect of the completion of coating with a smaller number of times of immersion repetition treatment as compared to the case without pNPh addition is considered. .

The present inventors have also found that the environmental stability of the PEDOT thus obtained is improved as compared with the case where no PEDOT is added.

Although the mechanism is unknown, it is thought that this is also due to the action of the nitro group of the electron donating substituent.

Then, as understood from (Table 1),
It has been found that the capacitor of the present embodiment has the same characteristics in loss coefficient and impedance, although the number of times of forming the electrolyte is smaller than that of the capacitor according to the seventh embodiment.

Since the environmental stability of PPy thus obtained was high, it was easily expected that this capacitor was excellent also in heat resistance and humidity resistance.

(Embodiment 12) In this embodiment, instead of p-nitrophenol of Embodiment 10,
p-cyanophenol (A), m-hydroxybenzoic acid (B), m-hydroxyphenol (C), acetophenol (D), nitrobenzoic acid (E), nitrobenzyl alcohol (F) Tenth embodiment
In the same manner as described above, ten capacitors were completed.

The same evaluation as in the first embodiment was performed on these, and the results are shown in the above (Table 1).

As can be understood from Table 1, the capacitor according to the present embodiment also exhibited the capacitor characteristics of the tenth embodiment.

Therefore, also in the present embodiment, it can be said that a capacitor element having a high capacity achievement ratio, a low loss, and an excellent high-frequency impedance characteristic can be efficiently obtained.

[0155]

As described above, the present invention relates to a capacitor comprising a conductive polymer monolayer containing EDTT as a repeating unit or a composite conductive layer comprising a conductive polymer containing pyrrole or EDOT as a repeating unit, Alternatively, at least one electrode provided opposite to the capacitor is formed by using a conductive layer obtained by combining a conductive polymer containing EDTT as a repeating unit in addition to the composite conductive layer. .

Since the PEDTT layer can be formed by applying a solution, it is possible to easily form the conductive polymer layer also on the deep portion of the capacitor electrode made of an etching pit or a porous sintered body.

[0157] Compared to conventional electrolytes, PEDTT is
Although the electrical conductivity is high, since it is lower than PPy or PEDOT, by using it as an electrolyte in combination with these, it is possible to realize a capacitor having an excellent loss coefficient and high-frequency characteristics as compared with the case of using alone. .

In the case of chemical polymerization, a problem arises.
Since PPy and PEDOT obtained by in-situ polymerization have low edge coverage, the number of processing repetitions for forming the polymer layer must be increased, but the outermost layer is added in addition to the composite conductive layer described above. The use of the PEDTT solution has a specific effect that the process can be simplified.

In the method of manufacturing a capacitor according to the present invention, the PEDTT layer is desirably formed by solution coating, but may be formed by other chemical polymerization or electrolytic polymerization.

Further, PPy and PEDOT, which are complexed with PEDTT, can be formed by chemical polymerization or electrolytic polymerization.

Furthermore, by conducting polymerization of PPy and PEDOT in a system in which a phenol derivative or a nitrobenzene derivative is present, the former can increase the electric conductivity, and the latter can increase the polymerization rate.
This has the effect of improving the capacitor characteristics or facilitating the manufacture of the capacitor.

When the composite conductive layer is formed by electrolytic polymerization, the PEDTT layer functions as a mediating conductive layer for growing the electrolytic polymerization film.

As the mediating conductive layer for the growth of the electrolytic polymer film,
Unlike the case of forming pyrolytic manganese dioxide, which has been conventionally used, no heat treatment is required, so that there is an effect that the deterioration of the dielectric film is small and the process can be simplified.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a capacitor according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a capacitor according to a third embodiment of the present invention.

FIG. 3 is a conceptual diagram of a capacitor according to a sixth embodiment of the present invention.

FIG. 4 is a conceptual diagram of a capacitor according to a ninth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode valve metal 2a, 2b Electrode 3 Dielectric 4, 6, 7 Conductive polymer layer 5 Cathode

Claims (27)

[Claims] 1. A capacitor comprising a conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit in at least one of a pair of electrodes provided to face each other with a dielectric layer interposed therebetween. . 2. A first conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit, at least one of a pair of electrodes provided to face each other with a dielectric layer interposed therebetween. A capacitor comprising a second conductive polymer layer containing pyrrole or 3,4 ethylenedioxythiophene as a repeating unit. 3. The laminated conductive polymer layer is provided so as to be adjacent to the second conductive polymer layer on the side opposite to the first conductive polymer layer, and the 3,4-ethylenedithia The capacitor according to claim 1, further comprising a third conductive polymer layer containing thiophene as a repeating unit. 4. The capacitor according to claim 1, wherein the dielectric layer is an oxide film of a valve metal constituting one of the electrodes. 5. The capacitor according to claim 4, wherein the valve metal is aluminum or tantalum. 6. The capacitor according to claim 1, wherein the dielectric layer is a polymer dielectric. 7. The capacitor according to claim 6, wherein the polymer is a polyimide. 8. The capacitor according to claim 1, wherein the first conductive polymer layer is adjacent to the dielectric layer. 9. A step of arranging a pair of electrodes facing each other,
A dielectric layer forming step of forming a dielectric layer between the electrodes,
A step of preparing a conductive polymer solution containing 3,4-ethylenedithiathiophene as a repeating unit; and a step of applying the conductive polymer solution between the electrodes to form a conductive polymer layer. Manufacturing method of the provided capacitor. 10. A step of arranging a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a step of using 3,4-ethylenedithiathiophene as a repeating unit between the electrodes. A conductive polymer layer forming step of forming a conductive polymer layer containing the conductive polymer layer by chemical polymerization. 11. A step of arranging a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a step of forming a conductive layer on at least one of the dielectric surfaces. Forming a conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit by electrolytic polymerization between the electrodes. 12. A step of disposing a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a conductive polymer containing 3,4-ethylenedithiathiophene as a repeating unit. A step of preparing a solution, a first conductive polymer layer forming step of forming a first conductive polymer layer by applying the solution between the electrodes, and repeating pyrrole or 3,4-ethylenedioxythiophene A method for manufacturing a capacitor, comprising: a laminated conductive polymer layer forming step having a second conductive polymer layer forming step of forming a second conductive polymer layer containing as a unit by chemical polymerization. 13. A step of disposing a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a conductive polymer containing 3,4-ethylenedithiathiophene as a repeating unit. A step of preparing a solution, a first conductive polymer layer forming step of forming a first conductive polymer layer by applying the solution between the electrodes, and repeating pyrrole or 3,4-ethylenedioxythiophene A method for manufacturing a capacitor, comprising: a laminated conductive polymer layer forming step including a second conductive polymer layer forming step of forming a second conductive polymer layer containing as a unit by electrolytic polymerization. 14. A step of arranging a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a step of using 3,4-ethylenedithiathiophene as a repeating unit between the electrodes. A first conductive polymer layer forming step of forming a first conductive polymer layer comprising forming a first conductive polymer layer by chemical polymerization;
-Forming a second conductive polymer layer containing ethylenedioxythiophene as a repeating unit by chemical polymerization;
A method of manufacturing a capacitor, comprising: a step of forming a laminated conductive polymer layer having the step of forming a conductive polymer layer. 15. A step of arranging a pair of electrodes facing each other, a step of forming a dielectric layer between the electrodes, and a step of using 3,4-ethylenedithiathiophene as a repeating unit between the electrodes. A first conductive polymer layer forming step of forming a first conductive polymer layer by forming a conductive polymer layer containing the same by chemical polymerization;
-Forming a second conductive polymer layer containing ethylenedioxythiophene as a repeating unit by electrolytic polymerization;
A method of manufacturing a capacitor, comprising: a step of forming a laminated conductive polymer layer having the step of forming a conductive polymer layer. 16. The laminated conductive polymer layer forming step includes forming a third conductive polymer layer containing 3,4-ethylenedithiathiophene as a repeating unit, opposite to the first conductive polymer layer. The method of manufacturing a capacitor according to claim 12, further comprising a third conductive polymer layer forming step of forming a third conductive polymer layer adjacent to the second conductive polymer layer on the side. 17. The method according to claim 16, wherein the third conductive polymer layer forming step is a step of forming the conductive polymer layer by applying a solution in which the conductive polymer is dissolved. 18. The method according to claim 1, wherein in the chemical polymerization step for forming the second conductive polymer, chemical polymerization is further performed using a solution containing a phenol derivative or a nitrobenzene derivative.
18. The method for manufacturing a capacitor according to any one of 2, 14, 16, and 17. 19. The method according to claim 18, wherein the phenol derivative is nitrophenol, cyanophenol, hydroxybenzoic acid, hydroxyphenol or acetophenol, or a combination thereof. 20. The method according to claim 18, wherein the nitrobenzene derivative is nitrobenzoic acid, nitrobenzyl alcohol, or a combination thereof. 21. The method according to claim 1, wherein in the electrolytic polymerization step for forming the second conductive polymer, electrolytic polymerization is further performed using a solution containing a phenol derivative or a nitrobenzene derivative.
A method for manufacturing a capacitor according to any one of 3, 15 to 17, above. 22. The method according to claim 21, wherein the phenol derivative is nitrophenol, cyanophenol, hydroxybenzoic acid, hydroxyphenol or acetophenol, or a combination thereof. 23. The method according to claim 21, wherein the nitrobenzene derivative is nitrobenzoic acid, nitrobenzyl alcohol, or a combination thereof. 24. The method of manufacturing a capacitor according to claim 9, wherein in the step of forming a dielectric, the dielectric is formed by anodic oxidation of a valve metal. 25. The method of manufacturing a capacitor according to claim 9, wherein the valve metal forming one of the electrodes is aluminum or tantalum. 26. The method of manufacturing a capacitor according to claim 20, wherein the dielectric forming step is a spin coating step of forming a dielectric using a polymer. 27. The polymer according to claim 37, wherein the polymer is a polyimide.
A method for manufacturing the capacitor as described in the above.