WO2006068302A1

WO2006068302A1 - Solid electrolytic capacitor element, solid electrolytic capacitor and method for manufacturing same

Info

Publication number: WO2006068302A1
Application number: PCT/JP2005/024155
Authority: WO
Inventors: Kazumi Naito; Katutoshi Tamura
Original assignee: Showa Denko K.K.
Priority date: 2004-12-24
Filing date: 2005-12-22
Publication date: 2006-06-29
Also published as: TW200636780A; TWI469163B

Abstract

Disclosed is a method for manufacturing a solid electrolytic capacitor element wherein a conductor having a dielectric layer in the surface is provided with a semiconductor layer containing a conductive polymer. Specifically, a solid electrolytic capacitor element is manufactured by impregnating a conductor having a dielectric layer in the surface with a dopant and then applying current thereto for forming a semiconductor layer. By using the thus-manufactured solid electrolytic capacitor element, there can be obtained a high-capacity solid electrolytic capacitor having good ESR.

Description

Description Solid electrolytic capacitor element, solid electrolytic capacitor and manufacturing method thereof Technical Field

The present invention relates to a method for manufacturing a solid electrolytic capacitor element having a low equivalent series resistance (ESR) value and a high capacity. Background art

Aluminum capacitors and tantalum solid electrolytic capacitors are known as high-capacitance and low-ESR capacitors used in various electronic devices.

The solid electrolytic capacitor was formed on the surface layer of an aluminum foil having fine pores on the surface layer and a sintered body of tantalum powder having fine pores inside as one electrode (conductor). It is produced by sealing a solid electrolytic capacitor element composed of a dielectric layer and the other electrode (usually a semiconductor layer) provided on the dielectric layer and an electrode layer laminated on the other electrode. ing.

As the semiconductor layer, an organic compound or an inorganic compound is used, but a conductive polymer is preferably used in consideration of the heat resistance and low ESR characteristics of the produced capacitor. This conductive polymer is a polymer having a high conductivity of ¹⁰ to ² to 10 ³ S · cm, and a polymer having a planar conjugated double bond (usually an insulator) High conductivity is exhibited by adding an electron donating compound called a dopant to a polymer having extremely low conductivity. As a specific example of the method for forming a conductive polymer as a semiconductor layer, a single molecule (monomer) that can become a conductive polymer in the pores of a conductor is used in the presence of a dopant, or an appropriate oxidizing agent or The method of superposing | polymerizing by supplying an electron can be mentioned. When a single molecule is polymerized, a dopant is taken in to obtain a conductive polymer. In Patent No. 1 9 4 5 3 5 8 and Patent No. 2 8 1 1 6 4 8, a semiconductor is formed by laminating an electropolymerization layer by an energization method after forming a chemical polymerization layer using an oxidizing agent. A method of forming a layer is described. Disclosure of the invention

Today's electronic devices tend to be designed to flow high current instantaneously with high power consumption and low operating voltage. Solid electrolytic capacitors used for this purpose are large-capacity capacitors that exhibit lower ESR values. Is in the direction of needing. However, if the volume of the conductor required for the large-capacity capacitor is constant, the pores inside the conductor must be made finer and the internal surface area must be increased, and as a result, the conductor dielectric There was a problem that the semiconductor layer formed on the layer was not sufficiently impregnated, and the resistance of the fabricated semiconductor layer was high. In other words, there has been a limit to making the conventional high-capacitance capacitors used at such high power consumption and low voltage further high-capacity and low ESR.

Accordingly, an object of the present invention is to provide a method for producing a high-capacity solid electrolytic capacitor having a good ESR value.

As a result of diligent studies to solve the above problems, the present inventors have supplied a sufficient amount of dopant to the conductor by forming a semiconductor layer by a current application method on the conductor impregnated with the dopant after forming the dielectric layer. At the same time, the semiconductor layer can be formed to a desired level, and it has been found that a high-capacity solid electrolytic capacitor element exhibiting a lower ESR value can be obtained, thereby completing the present invention. That is, the present invention provides the following method for producing a solid electrolytic capacitor element and a solid electrolytic capacitor produced using the method.

1. In a method for manufacturing a solid electrolytic capacitor element in which a semiconductor layer containing a conductive polymer is formed on a conductor having a dielectric layer on the surface, the conductor having a dielectric layer on the surface is impregnated with a dopant, A method for producing a solid electrolytic capacitor element, characterized in that a semiconductor layer is formed by an energization method. 2. dopant, the manufacture of the solid electrolytic capacitor element of the 1, wherein electric conductivity of an electron-donating compound providing 10 one ¹ ~ ¹ 0 ³ S · cm one ^first conductive polymer upon doping during electropolymerization Method.

3. The method for producing a solid electrolytic capacitor element as described in 1 or 2 above, wherein the dopant is at least one selected from a compound having a sulfonic acid group and a boron compound in which a carboxylic acid is coordinated to a boron atom.

4. The method for producing a solid electrolytic capacitor element as described in 1 above, wherein the conductor is a metal mainly composed of at least one selected from tantalum, niobium, titanium and aluminum, niobium oxide, or a mixture thereof. .

5. The semiconductor layer has the following general formula (1) or (2)

(1) (2)

(Wherein 1 ^ to 1 ⁴ are each independently a hydrogen atom, was or alkyl group having 1 to 6 carbon atoms an alkoxy group having 1 to 6 carbon atoms, X is oxygen, Iou or ChissoHara child R ⁵ is present only when X is a nitrogen atom and represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ¹ and R ² and R ³ and R ⁴ are bonded to each other to form a ring. May be.)

2. The method for producing a solid electrolytic capacitor element according to 1 above, which is at least one layer selected from a semiconductor mainly composed of a conductive polymer in which a dopant is added to a polymer containing a repeating unit represented by formula (1).

6. A polymer containing a repeating unit represented by the general formula (1) is represented by the following general formula (3)

(In the formula, each of ¹⁶ and ¹⁷ is independently a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms, or an alkyl group thereof. And a substituent which forms a cyclic structure of at least one 5- to 7-membered saturated hydrocarbon containing two oxygen atoms and is substituted with the cyclic structure. Those having a good vinylene bond and those having a phenylene structure which may be substituted are also included.

6. The method for producing a solid electrolytic capacitor element as described in 5 above, wherein the polymer is a polymer containing a structural unit represented by

7. The conductive polymer is described in 5 above, wherein the conductive polymer is selected from polyaniline, polyoxyphenylene, polyphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylpyrrole, and substituted derivatives and copolymers thereof. Manufacturing method of the solid electrolytic capacitor element.

8. The method for producing a solid electrolytic capacitor element as described in 7 above, wherein the conductive polymer is poly (3,4-ethylenedioxythiophene).

9. Semiconductors conductivity is 1 0 ^2-1 0 ³ manufacturing method of a solid electrolytic capacitor element of the mounting serial in S · cm- the 5 ¹ by weight.

10. A solid electrolytic capacitor element obtained by the production method according to any one of 1 to 9 above.

1 1. A solid electrolytic capacitor in which the solid electrolytic capacitor element described in 10 above is sealed.

1 2. An electronic circuit using the solid electrolytic capacitor described in 1 1 above.

1 3. Electronic equipment equipped with the solid electrolytic capacitor as described in 1 1 above. The present invention provides a method for producing a solid electrolytic capacitor element in which a conductor layer impregnated with a dopant after formation of a dielectric layer is formed by a current application method, and a solid electrolytic capacitor in which the capacitor element obtained by the method is sealed Therefore, according to the present invention, a solid electrolytic capacitor having a low initial ESR value and a high capacity can be produced. BEST MODE FOR CARRYING OUT THE INVENTION

A method for producing a solid electrolytic capacitor element of the present invention and one embodiment of a solid electrolytic capacitor using the solid electrolytic capacitor element will be described.

Examples of the conductor used in the present invention include a metal containing at least one selected from tantalum, niobium, titanium and aluminum as a main component (a component of 50% by mass or more), niobium monoxide, or a mixture thereof. Is mentioned. The metal may be an alloy.

When a metal is used as the conductor, a part of the metal may be used after at least one treatment selected from carbonization, phosphation, boronation, nitridation, and sulfidation. The shape of the conductor is not particularly limited, and may be a foil shape, a plate shape, or a rod shape. The conductor is obtained by molding a powdered conductor material or sintering after molding. You may sinter by attaching a powdery conductor to a part of foil-like or plate-like metal. The surface of the conductor may be processed by etching or the like to have fine pores. In the molded body or the sintered body, fine pores can be provided inside the molded or sintered body by appropriately selecting the pressure during molding.

The lead can be directly connected to the conductor. However, if the conductor is a molded or sintered body, a part of the lead wire (or lead foil) prepared separately at the time of molding together with the conductor. The part outside the molded lead wire (or lead foil) can be used as a lead for one electrode of the solid electrolytic capacitor element.

In addition, a semiconductor layer is not formed on a part of the conductor and left as an anode part. You can also. An insulating resin may be adhered and cured in a headband shape at the boundary between the anode part and the semiconductor layer forming part in order to prevent the semiconductor layer from creeping up.

Preferable examples of the conductor of the present invention include tantalum powder, niobium powder, alloy powder containing tantalum as a main component, alloy powder containing niobium as a main component, powder such as niobium monoxide powder, and the like. Examples thereof include a sintered body having a large number of pores and an aluminum foil whose surface is etched.

When a sintered body of a conductor is produced using powder having a small particle size, a sintered body having a large specific surface area per mass can be produced. In the present invention, the CV value (product of capacity and formation voltage described later) is 80,000 / F VZ g or more for tantalum powder, and 150,000 μ F VZ g or more for niobium powder or niobium monoxide powder. The mass can be 4 O mg or more. The solid electrolytic capacitor element produced in this way is preferable because it has a small volume and a large capacity.

The dielectric layer formed on the conductor surface of the present invention includes at least one selected from metal oxides such as T a ₂ 0 ₅ , A 1 ₂ O ₃ , T i 0 ₂ , and N b ₂ 0 _5. Examples thereof include a dielectric layer as a main component. These dielectric layers are formed in an electrolyte containing an organic acid or organic acid salt such as acetic acid, adipic acid, or benzoic acid, or a mineral acid or mineral acid salt such as phosphoric acid, sulfuric acid, boric acid, or silicic acid. It is formed by applying a voltage between the anode side of the conductor and the cathode plate separately arranged in the electrolyte (referred to as “chemical conversion”). The formation temperature, formation time, current density during formation, etc. are determined in consideration of the type, mass and size of the conductor, the capacity and operating voltage of the target solid electrolytic capacitor element, and the like. The formation temperature is usually from room temperature to 10 ° C or less, and the formation time is usually from several hours to several hours. After the formation, the electrolytic solution adhering to the conductor is washed with water or an appropriate organic solvent such as alcohol and then dried.

In the present invention, before providing a semiconductor layer on a conductor formed with a dielectric layer by an energization method, the conductor is impregnated with a dopant so that a dopant is contained in the pores inside the conductor. Is essential. Conductor with finer pores than before The reason is not clear by impregnating with a dopant after forming a dielectric layer on the semiconductor layer, but it is possible to provide a semiconductor layer uniformly deep inside the pores and supply sufficient dopant to the semiconductor layer. be able to. The solid electrolytic capacitor fabricated in this way has a lower ESR and a larger capacity than conventional capacitors with the same volume of conductor.

A conventionally known dopant is used as a dopant to be impregnated in a conductor. Particularly, pyrrole or 3,4-ethylenedioxythiophene is used as a representative monomer, and conductivity is 1 when doped simultaneously with polymerization by electrolytic polymerization. 0 - ¹ to 0 ³ gives the S · cm- ¹ conductive polymer de one dopant is preferable. For example, a compound having a sulfonic acid group as a dopant and a boron compound in which a rubonic acid is coordinated to a boron atom can be mentioned. Such compounds include benzene sulphonic acid, tonole senophonic acid, xylene sulphonic acid, ethenole benzene sulphonic acid, naphthalene / lefonic acid, anthracene sulphonic acid, benzoquinone sulphonic acid, naphthoquinone sulphonic acid and anthraquinone sulphonic acid Various oligomers or polymers such as sulfonic acid having an aryl group such as sulfonic acid having an alkyl group such as butyl sulfonic acid, hexeno sulfonic acid, and hexyl sulfonic acid, and polybulu sulfonic acid (degree of polymerization: 2 to As typical examples, sulfonic acids and salts of these sulfonic acids (ammonium salts, alkali metal salts, alkaline earth metal salts, transition metal salts such as iron, and other various metal salts) can be given. These compounds may have various substituents, and a plurality of sulfonic acid groups may exist. Examples thereof include 2,6-naphthalenedisulfonic acid, 1,2-ethanedisulfonic acid, and the like. Examples of boron compounds include ammonium borodisalicylate and its hydrate, boro-1,2-carboxybenzene ammonium, and the like. In addition, a dopant may be used in combination with a plurality of dopants.

One example of a method for impregnating a conductor with a dopant is to dissolve or partially suspend the dopant in at least one solvent selected from water or an organic solvent. A method of immersing the conductor in the solution and drying the solvent after pulling up can be mentioned. Part of the solvent used may remain in the conductor. When the dopant is liquid at room temperature, the conductor may be directly dipped in the dopant without using a solvent and pulled up. After pulling up, drying at a temperature higher than normal temperature or rinsing the conductor surface layer with an appropriate solvent to remove the dopant on the conductor surface and then forming the semiconductor layer in the next step Good. It is preferable to impregnate the conductor with the dopant and remove the solvent in multiple steps, since the dopant is uniformly introduced deep into the conductor.

Re-formation may be performed to repair minute defects in the dielectric layer caused by impregnation with the dopant. The re-chemical conversion method can be carried out in the same manner as chemical conversion using the reagent used for the chemical conversion described above. It is also possible to use the dopant used for the dopant impregnation of the conductor in the re-forming reagent. If a dopant is used in the re-formation reagent, the exudation of the dopant from the conductor due to the formation may be mitigated.

On the other hand, examples of the other electrode formed on the dielectric layer of the conductor impregnated with the dopant include at least one organic semiconductor selected from conductive polymers described later. In addition, these conductive polymers may be included in the first layer, and at least one compound selected from organic semiconductors and inorganic semiconductors may be included as the second layer, or both may be included as a mixture. Good.

Specific examples of the organic semiconductor include an organic semiconductor composed of a benzopyrroline tetramer and chloranil, an organic semiconductor composed mainly of tetrathiotetracene, an organic semiconductor composed mainly of tetracyanoquinodimethane, the following general formula (1) or ( Examples thereof include organic semiconductors mainly composed of a conductive polymer obtained by doping a polymer containing a repeating unit represented by 2) with a dopant.

(1) (2)

In the formulas (1) and (2), R to R ⁴ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and X represents oxygen, io or nitrogen R ⁵ is present only when X is a nitrogen atom and represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ¹ and R ² and R ³ and R ⁴ are bonded to each other. It may be annular.

Furthermore, in the present invention, the polymer containing the repeating unit represented by the general formula (1) is preferably a polymer containing a structural unit represented by the following general formula (3) as a repeating unit.

In the formula, each of ¹⁶ and ¹⁷ is independently a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms, or an alkyl group thereof. It represents a substituent that is bonded at a position to form a cyclic structure of at least one 5- to 7-membered saturated hydrocarbon containing two oxygen atoms. The cyclic structure includes those having a vinylene bond which may be substituted and those having a phenylene structure which may be substituted.

A conductive polymer containing such a chemical structure is charged and doped with a dopant. The dopant is not particularly limited, and the conductor is formed before the semiconductor layer is formed. The same materials as mentioned as the dopant to be impregnated can be used.

The dopant used in the present invention is described as an uncharged compound, but when it actually acts as a dopant, it is partially charged and ionized (mainly anion). (For example, in the case of benzenesulfonic acid, also includes benzenesulfonic acid anion). Examples of the polymer containing repeating units represented by the formulas (1) to (3) include polyaniline, polyoxyfurene, polyphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylvillol, And substituted derivatives and copolymers thereof. Of these, polypyrrole, polythiophene, and substituted derivatives thereof (for example, poly (3,4-ethylenedioxythiophene)) are preferable.

The semiconductor layer described above is formed in a layered form by chemical polymerization (solution reaction, gas phase reaction, solid-liquid reaction and a combination thereof), electrolytic polymerization, or a combination of these methods. If at least the first layer of the semiconductor layer (the first layer) is prepared using the electrolytic polymerization method, the conductive polymer chain is not branched, or the semiconductor layer thickness on the outer surface of the conductor is uniform. Therefore, it is preferable because the initial ESR value of the capacitor is lower than that of other methods.

Specific examples of the inorganic semiconductor include at least one compound selected from molybdenum dioxide, tungsten dioxide, diacid oxide, manganese diacid manganese, and the like. The organic semiconductor and an inorganic semiconductor, conductivity 1 0 one ² ~ 1 0 ³ S - The use of those cm ^"1 range, is small no longer preferred ESR values of the solid electrolytic capacitor was fabricated.

The conductive polymer of the first layer of the semiconductor layer (the entire semiconductor layer if there are no remaining layers) is formed by an energization technique called electrolytic polymerization. An electropolymerization method is known in which an external electrode placed near the outer periphery of a conductor is used as an anode. However, without using such a method, electricity is applied using the anode portion or anode lead of the conductor as the anode and the cathode plate disposed in the semiconductor layer forming solution in which the conductor is immersed as the cathode. In addition, since polymerization starts from the inside of the conductor, even a conductor having fine pores is preferably uniformly polymerized, and semiconductor deposition is improved.

In the present invention, re-formation may be performed to repair a minute defect in the dielectric layer caused by the formation of the semiconductor layer. Further, the energization and re-formation for forming the semiconductor layer may be repeated a plurality of times, or the energization conditions at the time of repetition may be changed. Normally, when stopping the energization, the conductor is pulled up from the semiconductor layer forming solution to perform cleaning / drying, but the energization / energization stop / cleaning / drying process is repeated several times before entering the re-forming process. Also good. The reason for this is not clear, but the mass of the semiconductor layer may increase if the total energization time is set to the same value, followed by energization, de-energization, cleaning, and drying.

Re-chemical conversion can be performed in the same manner as the above-described dielectric layer forming method. The re-forming voltage shall be below the forming voltage.

In addition, as a pretreatment for increasing the formation ratio of the semiconductor layer, after forming a microprojection on the dielectric layer formed on the surface of the conductor layer to produce an electrical microdefect, A semiconductor layer may be formed by a method.

When the semiconductor layer is formed in a plurality of times, re-formation may be performed any number of times at any time during the formation of the semiconductor layer, but it is desirable to perform re-formation after the final semiconductor layer is formed.

In the present invention, an electrode layer is provided on the semiconductor layer formed by the above-described method or the like. The electrode layer can be formed, for example, by solidifying a conductive paste, plating, metal vapor deposition, adhesion of a heat-resistant conductive resin film, or the like. As the conductive paste, a silver paste, a copper paste, an ano-reminium paste, a carbon paste, a nickel paste, etc. are preferable, but these may be used alone or in combination of two or more. If two or more types are used, they may be mixed or stacked as separate layers. After applying conductive paste, leave in air or heat to solidify. The main component of the conductive paste is conductive powder such as resin and metal, but a solvent for dissolving the resin and a curing agent for the resin are also used if desired. The solvent will scatter during the heat solidification. As the resin, various known resins such as alkyd resin, acrylic resin, epoxy resin, phenol resin, imide resin, fluororesin, ester resin, imidoamide resin, amide resin, and styrene resin are used. As the conductive powder, powders of silver, copper, aluminum, gold, rikibon, nickel, alloys containing these metals as main components, and mixed powders thereof are used. The conductive powder is usually contained in 40 to 97% by mass. If it is less than 40% by mass, the conductivity of the produced conductive paste is small, and if it exceeds 97% by mass, the adhesiveness of the conductive paste becomes poor. The conductive paste may be used by mixing the aforementioned conductive polymer or metal oxide powder forming the semiconductor layer.

Examples of plating include nickel plating, copper plating, silver plating, gold plating, aluminum plating, and the like. Examples of the deposited metal include aluminum, nickel, copper, gold, and silver.

Specifically, for example, an electrode layer is formed by sequentially laminating a carbon paste and a silver paste on the formed semiconductor layer. In this way, a solid electrolytic capacitor element is fabricated by stacking the conductor up to the electrode layer.

The solid electrolytic capacitor element of the present invention configured as described above is, for example, a resin module.

—Solid electrolytic capacitor products for various applications can be packaged with metal foil, resin case, metallic outer case, resin dating, and laminating film. Among these, a chip-shaped solid electrolytic capacitor with a resin mold is particularly preferable because it can be easily reduced in size and cost. The capacitor according to the present invention will be described in detail. The capacitor according to the present invention has a lead frame (a tip portion disposed so as to be opposed to a gap) with a part of the electrode layer of the capacitor element prepared separately. And a part of the conductor is placed on the other tip of the lead frame. In this case, if the conductor has a structure with an anode lead, the anode You can cut the tip of the card. Subsequently, the cathode and anode of the capacitor element are electrically and mechanically joined to the respective leading ends of the lead frame by solidifying or welding the conductive paste, and a part of the leading end of the lead frame is left. Seal the resin and cut and bend the lead frame at a predetermined part outside the resin seal to fabricate the capacitor chip. (Note that the lead frame is on the bottom surface of the resin seal and only the bottom surface or bottom and side surfaces of the lead frame. If it is sealed with leaving, it may be cut only).

As described above, the lead frame is finally cut and becomes the external terminals of the capacitor. The shape of the lead frame is foil or flat plate, and the material is mainly iron, copper, aluminum or these metals. The alloy used as a component is used. At least one plating layer of solder, tin, titanium, gold, silver, nickel, palladium, copper, or the like may be applied to a part or all of the lead frame.

Various markings can be applied to the lead frame before or after the cutting and bending process. In addition, it is possible to perform the measurement before mounting and connecting the solid electrolytic capacitor element and to perform the re-measurement at any time after the sealing. The lead frame has a pair of opposed tip portions, and the gap between the tip portions insulates the anode portion and the electrode layer portion of each capacitor element. As the type of resin used for the resin mold exterior, known resins used for sealing capacitors such as epoxy resins, phenol resins, alkyd resins, ester resins, and aryl ester resins can be employed. When using a low-stress resin (for example, a resin that usually contains 70% by volume or more of filler and has a thermal expansion coefficient α of 3 X 10 ⁵ ° or less) that is generally commercially available for each resin. This is preferable because the generation of sealing stress on the capacitor element at the time of stopping can be mitigated. In addition, a transfer machine is preferably used for sealing the resin. The solid electrolytic capacitor thus fabricated may be subjected to an aging treatment to repair the deterioration of the thermal and / or physical dielectric layer during electrode layer formation and exterior. The aging method is performed by applying a predetermined voltage (usually within twice the rated voltage) to the capacitor. Aging time and temperature are determined in advance by experiment because optimum values differ depending on the type, capacity, and rated voltage of the capacitor.Normally, the time is from several minutes to several 3, and the temperature is determined in consideration of the thermal deterioration of the voltage application jig. Performed at 300 ° C or lower.

The aging atmosphere may be performed under any conditions of reduced pressure, normal pressure, and increased pressure. Further, the aging atmosphere may be air, a gas such as argon, nitrogen, or helium, but is preferably water vapor. Aging may be performed in an atmosphere containing water vapor, and then in a gas such as air, argon, nitrogen, or helium, and stabilization of the dielectric layer may proceed. After supplying water vapor, return to normal pressure and room temperature, or after supplying water vapor, leave it at a high temperature of 15 to 25 ° C. for several minutes to several hours to remove excess water and perform the above aging Is also possible. One example of a water vapor supply method is a method of supplying water vapor by heat from a water reservoir placed in an aging furnace.

The voltage application method can be designed to allow direct current, alternating current with an arbitrary waveform, alternating current superimposed on direct current, and pulsed current. It is also possible to stop the voltage application in the middle of aging and apply the voltage again. Aging may be performed while increasing the voltage in order from the low voltage to the high voltage. The solid electrolytic capacitor manufactured by the present invention can be preferably used for a circuit using a high-capacitance capacitor such as a central processing circuit and a power supply circuit, and these circuits include a personal computer, a server, a camera, a game machine, It can be used for various digital devices such as DVDs, AV devices and mobile phones, and electronic devices such as various power supplies. The solid electrolytic capacitor manufactured by the present invention has a large capacity and a good initial ESR value. By using this solid electrolytic capacitor, a highly reliable electronic circuit and electronic device that generates little heat even when a large current flows are obtained. Can do. Example Hereinafter, specific examples of the present invention will be described in more detail. However, the present invention is not limited to the following examples.

Examples 1-3:

Niobium primary powder (average particle size 0.30 πι) pulverized using the hydrogen embrittlement of niobium ingot is granulated, and niobium powder with an average particle size of 1 30 μπι Oxygen is present at 105000 ppm). Next, it is left in a nitrogen atmosphere at 45 ° C. and then in argon at 70 ° C., so that it is partially nitrided niobium powder (C V297000 // F- V / g). This niobium powder was formed with a 0.48mm diameter niobium wire and sintered at 1270 ° C to produce multiple sintered bodies (conductors) of size 4.1 X 3.5 X 1.0mm (each mass 0.06 g The tube leads are 3.7 mm inside the sintered body and 8 mm outside.

Subsequently, by forming at 70 ° C., 20 V, 8 hours in a 0.5 mass% phosphoric acid aqueous solution, a dielectric mainly composed of niobium pentoxide is formed on the sintered body surface and part of the lead wire. A body layer was formed. The sintered body was subsequently immersed in an alcohol solution in which the compound described in Table 1 as a dopant was dissolved, and then dried to remove the alcohol. Such dopant impregnation and alcohol removal were repeated 10 times. Next, the surface of the conductor was washed with alcohol and dried.

Furthermore, the sintered body was prepared in a tank containing a mixed solution of 30% by mass ethylene glycol and water in which a small amount of pyrrole monomer and 4% anthraquinone-2-sulfonic acid were separately prepared. Electrode polymerization at 100 A for 60 minutes with the lead wire of the sintered body as the anode and the external electrode as the cathode for 60 minutes, withdrawn from the tank, and washed with water After alcohol washing and drying, re-formation was performed in 1% by weight phosphoric acid aqueous solution at 70 ° C and 13 V for 15 minutes. This electrolytic polymerization and re-formation were repeated 6 times to form a semiconductor layer made of polypyrrole on the dielectric layer.

Next, a carbon paste is laminated on the semiconductor layer and dried to form a carbon layer. Then, a silver paste mainly composed of 90% by mass of silver powder and 10% by mass of acrylic resin was laminated and then dried to form an electrode layer, thereby producing a plurality of solid electrolytic capacitor elements. The lead wire on the sintered body side and the electrode layer side on a pair of both ends of a lead frame (10 μΐη semi-bright nickel plating on both sides of the copper alloy), which is a separately prepared external terminal The former was spot welded, and the latter was connected electrically and mechanically with the same silver paste used for the electrode layer. After that, transfer mold with epoxy resin except for a part of the lead frame, cut the specified part of the lead frame outside the mold and then bend it along the exterior to make it an external terminal 7.3 X 4.3 X 1.8mm A chip-shaped solid electrolytic capacitor was fabricated. Subsequently, after aging for 3 hours at 125 ° C and 7V, the final temperature was increased by passing through a tunnel furnace with a peak temperature of 2700 ° C and 23 ° C at 35 ° C for 35 seconds. A chip-shaped solid electrolytic capacitor was obtained. Comparative Example 1:

A chip-shaped solid electrolytic capacitor was produced in the same manner as in Example 1 except that the conductor in which the dielectric layer was formed in Example 1 was not impregnated with the dopant. Example 4:

The electrolytic polymerization in Example 1, carried out at a bath 4% naphthalene one 2-sulfonic acid containing 3 0 mass ^_0/0 mixed solution of ethylene da recall and water dissolved in place of 4% anthraquinone one 2- sulfonic acid A chip-shaped solid electrolytic capacitor was produced in the same manner as in Example 1 except that. Comparative Example 2:

A chip-shaped solid electrolytic capacitor was produced in the same manner as in Example 4 except that the conductor in which the dielectric layer was formed in Example 4 was not impregnated with the dopant. Examples 5-8:

CV (product of capacitance and formation voltage) 1 Tantalum sintered body of 50,000 μF · VZ g (size 4.4X 1.0 X 3.0mm, mass 8 2 mg, tantalum lead wire 0.40m πι φ is 1 O mm) The surface is used as a conductor. A tetrafluoroethylene washer was attached to the lead wire to prevent the solution from splashing when the semiconductor layer was formed in the subsequent process.

Immerse the sintered body to be the anode in 1% by mass anthraquinone_2-sulfonic acid aqueous solution, excluding a part of the lead wire, apply 1 OV between the cathode and the tantalum plate electrode, and 65 ° C A dielectric oxide film layer made of Ta ₂ O ₅ was formed by chemical conversion for 7 hours. Except for the lead wire of this sintered body, it was immersed in an alcohol (ethanol) solution in which the compound described in Table 1 as a dopant was dissolved, and then dried to remove the alcohol. Such dopant impregnation and alcohol removal were repeated 5 times.

Next, a sufficient amount of 3,4-ethylenedioxythiophene monomer and 4% anthraquinone-2-sulfonic acid were prepared separately, except for the lead wires of the sintered body, so that insoluble portions were also present. dissolved 3 0 mass ^_0/0 ethylene da recall and mixed-solution vessel containing water (tantalum foil in a bath bottom of polypropylene becomes external electrodes have been attached.) immersed in, the sintered body of lead Electrolytic polymerization is conducted for 60 minutes at 120 μA with the wire as the anode and the external electrode as the cathode. After pulling out of the tank, water washing 'alcohol washing' and drying, 1% anthraquinone mono-2-sulfonic acid Re-formation was performed in an aqueous solution at 65 ° C and 7 at 15 minutes. This electrolytic polymerization and re-formation were repeated 6 times to form a semiconductor layer made of a polythiophene derivative on the dielectric layer.

Subsequently, an electrode layer was formed on the semiconductor layer in the same manner as in Example 1, and then an epoxy resin was sealed to produce a chip-shaped solid electrolytic capacitor. Subsequently, it was aged for 3 hours at 13.5 ° C. and 3 V, and was further left for 15 minutes in a furnace at 1850 ° C. to cure the exterior resin, resulting in a final chip-shaped solid electrolytic capacitor. Comparative Example 3:

A chip-shaped solid electrolytic capacitor was produced in the same manner as in Example 5 except that the conductor in which the dielectric layer was formed in Example 5 was not impregnated with the dopant. Example 9:

The capacitor was set in the same manner as in Example 5 except that the size of the sintered body was 4.4X3.0X3.0mm, the mass was 245 mg, and the size of the chip-shaped solid electrical square capacitor was 7.3X4.3X3.8mm. Produced. Comparative Example 4:

A chip-shaped solid electrolytic capacitor was produced in the same manner as in Example 9 except that the conductor on which the dielectric layer was formed in Example 9 was not impregnated with the dopant. The performances of the chip-shaped solid electrolytic capacitors produced in Examples 1 to 9 and Comparative Examples 1 to 4 were measured by the following method, and are summarized in Table 2. The data in Table 2 is the average value of 30 capacitors.

Capacity: Measured at 12 OHz at room temperature using an LCR measuring instrument manufactured by Huylet Packard.

E S R: The equivalent series resistance of the capacitor was measured at 100 kHz.

LC: Examples 1 to 4 and Comparative Examples 1 and 2 were measured at a rated voltage of 4 V. Examples 5 to 9 and Comparative Examples 3 to 4 were measured at a rated voltage of 2.5 V and a room temperature of 30 seconds. table 1

Table 2

By comparing Examples 1 to 9 and Comparative Examples 1 to 4, when a semiconductor layer was formed on a conductor impregnated with a dopant after forming a dielectric layer by a current application method, It can be seen that the body electrolytic capacitor has a high capacity and a good ESR value. In particular, even if the volume of the conductor is increased, these characteristics are good without deterioration.

Claims

The scope of the claims

1. In a method of manufacturing a solid electrolytic capacitor element in which a semiconductor layer containing a conductive polymer is formed on a conductor having a dielectric layer on the surface, a method of conducting electricity after impregnating a dopant in a conductor having a dielectric layer on the surface A method for producing a solid electrolytic capacitor element, wherein a semiconductor layer is formed by:

2. Dopants, electric conductivity of ^{^{1 0- 1 ~ 1 0 3 S}} · cm- 1 for providing a conductive polymer solid electrolytic capacitor element according to claim 1 wherein the electron donor compound when doped at the electrolytic polymerization Manufacturing method.

3. The method for producing a solid electrolytic capacitor element according to claim 1 or 2, wherein the dopant is at least one selected from a compound having a sulfonic acid group and a boron compound in which a carboxylic acid is coordinated to a boron atom.

4. The method for producing a solid electrolytic capacitor element according to claim 1, wherein the conductor is a metal mainly composed of at least one selected from tantalum, niobium, titanium, and aluminum, niobium oxide, or a mixture thereof. The semiconductor layer has the following general formula (1) or (2)

(2) are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Or an alkoxy group having 1 to 6 carbon atoms, X represents an oxygen atom, nitrogen atom or nitrogen atom, and R ⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which is present only when X is a nitrogen atom. R ¹ and R ² and R ³ and R ⁴ may be bonded to each other to form a ring. )

2. The method for producing a solid electrolytic capacitor element according to claim 1, wherein the polymer is a semiconductor containing at least one kind of a conductive polymer in which a dopant is doped in a polymer containing a repeating unit represented by formula (1).

6 —Polymer Power Containing Repeating Unit Represented by General Formula (1) General Formula (3)

(In the formula, 1 ⁶ and 1 ^ ⁷ are each independently a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms, or the alkyl group. It represents a substituent which is bonded at an arbitrary position to form a cyclic structure of at least one 5- to 7-membered saturated hydrocarbon containing two oxygen atoms, and the cyclic structure is substituted. Also included are those having a good vinylene bond and those having a phenylene structure which may be substituted.

The method for producing a solid electrolytic capacitor element according to claim 5, wherein the polymer comprises a structural unit represented by the formula: 7. The conductive polymer according to claim 5, wherein the conductive polymer is selected from polyaniline, polyoxyphenylene, polyphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylpyrrole, and substituted derivatives and copolymers thereof. The manufacturing method of the solid electrolytic capacitor element of description.

8. The method for producing a solid electrolytic capacitor element according to claim 7, wherein the conductive polymer is poly (3,4-ethylenedioxythiophene).

9. The semiconductor of conductivity is 1 0 ^2-1 0 ³ manufacturing method of a solid electrolytic capacitor element according to claim 5 is in a range of S · cm- ^1.

10. A solid electrolytic capacitor element obtained by the manufacturing method according to claim 1.

1 1. A solid electrolytic capacitor in which the solid electrolytic capacitor element according to claim 10 is sealed.

1 2. An electronic circuit using the solid electrolytic capacitor according to claim 1.

1 3. An electronic device on which the solid electrolytic capacitor according to claim 1 is mounted.