JP2002373834A - Method for manufacturing niobium capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor which has excellent LC characteristics and a small decrease in capacity due to DC bias application, and to provide its manufacturing method. SOLUTION: By this manufacturing method for the niobium capacitor, the niobium capacitor is manufactured by exposing a dielectric oxide film to 100 to 140 deg.C in its some process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel capacitor having a good high-temperature life characteristic and a small bias change, particularly a large capacitor per unit mass and a leakage current value (hereinafter referred to as "L").
C (may be abbreviated as C).

[0002]

2. Description of the Related Art Capacitors used in electronic devices such as cellular phones and personal computers are desired to be small in size and large in capacity. Among such capacitors, tantalum capacitors are preferably used because of their large capacity for their size and good performance. Normally, tantalum oxide is used as a dielectric of a tantalum electrolytic capacitor. To further increase the capacity, a niobium solid electrolytic capacitor using a niobium oxide having a higher dielectric constant as a dielectric has been considered. The present inventor has found that among niobium electrolytic capacitors, an electrolytic capacitor using a niobium sintered body partially nitrided as an electrode has a particularly large capacity and a large capacitance.
It has been suggested that the C characteristics are good (Japanese Patent Laid-Open No. 10-24).
2004). The capacitor manufactured using a niobium sintered body partially nitrided in the publication has a large capacity and a large capacitance.
Although the C characteristics are good, the capacitance is greatly reduced by the application of DC bias, and in order to obtain a capacitor having the desired capacitance, use a large amount of sintered body or sinter using niobium powder with a smaller particle size. The body needed to be made.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a capacitor having good LC characteristics and a small decrease in capacitance due to application of a DC bias, and a method of manufacturing the same.

[0004]

The decrease in capacitance due to the application of a DC bias is a characteristic peculiar to niobium, and is presumed to be due to the instability of niobium oxide, which is a main component of the dielectric layer.

The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, have found that niobium oxide, which is a main component of the dielectric layer, is stabilized by exposure to heat, leading to the completion of the present invention. Was. That is, the present invention relates to the following method for manufacturing a niobium capacitor, a capacitor obtained by the method, an electronic circuit using the capacitor, and an electronic device. (1) A method for manufacturing a niobium capacitor in which an oxide film is formed on a surface of a niobium sintered body, a semiconductor layer is formed on the oxide film, and a conductor layer is formed on the semiconductor layer, and the package is packaged and sealed. A method for manufacturing a niobium capacitor, comprising exposing a sintered body having an oxide film formed on a surface thereof and having no semiconductor layer formed thereon to a temperature in a range of 100 ° C. to 1400 ° C. (2) In a method for manufacturing a niobium capacitor, an oxide film is formed on a surface of a niobium sintered body, an organic semiconductor layer is formed on the oxide film, and a conductor layer is formed on the organic semiconductor layer, and the package is packaged and sealed. A niobium capacitor characterized in that an oxide film is formed on the surface of the sintered body and an organic semiconductor layer is formed on the oxide film, and the sintered body on which the conductor layer is not formed is exposed to a temperature in the range of 100C to 350C. Manufacturing method. (3) A method for manufacturing a niobium capacitor in which an oxide film is formed on the surface of a niobium sintered body, an organic semiconductor layer is formed on the oxide film, and a conductor layer is formed on the organic semiconductor layer, and the package is covered with a resin and sealed. An oxide film, a semiconductor layer, and a conductor layer are formed on the surface of the niobium sintered body, and the sintered body that is not sealed with resin is exposed to a temperature in a range of 100 ° C to 300 ° C. Manufacturing method for niobium capacitors. (4) The method for manufacturing a niobium capacitor according to any one of the above items 1 to 3, wherein the niobium sintered body contains 50 mass ppm to 400,000 mass ppm of one or more elements other than niobium. (5) The niobium sintered body is a niobium alloy sintered body, and lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, radium, scandium, yttrium, Lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, titanium, zirconium, hafnium, vanadium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, Ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium,
Platinum, copper, silver, gold, zinc, cadmium, mercury, boron,
Aluminum, gallium, indium, thallium, carbon, silicon, germanium, tin, lead, phosphorus, arsenic, antimony, bismuth, selenium, tellurium, polonium, as the sum of the content of at least one element selected from the group consisting of astatine The method for manufacturing a niobium capacitor according to any one of claims 1 to 4, wherein the niobium capacitor includes 50 mass ppm to 400,000 mass ppm. (6) The niobium sintered body contains at least one element selected from the group consisting of boron, nitrogen, carbon and sulfur elements,
The method for producing a niobium capacitor according to any one of claims 1 to 5, comprising 50 ppm to 200,000 ppm. (7) A method for manufacturing a niobium capacitor, comprising exposing a dielectric oxide film to a temperature in the range of 100 ° C. to 1400 ° C. in any one of the steps, followed by sealing. (8) A capacitor obtained by the manufacturing method according to any one of the above items 1 to 7. (9) An electronic circuit using the capacitor described in (8). (10) An electronic device using the capacitor described in (8).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a niobium capacitor according to the present invention will be described. In general, a niobium capacitor is manufactured by providing a dielectric oxide film layer containing niobium oxide as a main component on a first electrode and further providing a second electrode (counter electrode) on the dielectric oxide film layer. You. As the first electrode, niobium or an alloy thereof is preferably used because a niobium oxide layer is easily formed, and a sintered body thereof is preferably used to obtain a higher capacity.

For example, a niobium sintered body or a sintered body of a niobium alloy (hereinafter, unless otherwise specified, these sintered bodies are referred to as “niobium sintered body”) have an oxide film containing niobium oxide as a main component. A layer is formed by electrolytic formation or the like, and an inorganic semiconductor layer such as lead dioxide, manganese dioxide or the like, or polypyrrole, polythiophene, or poly (3,4-ethylenedioxythiophene) containing a dopant is formed outside the oxide film layer as a counter electrode. An organic semiconductor layer is formed. further,
On top of that, to reduce the contact resistance, carbon paste,
A niobium capacitor element is manufactured by forming a conductive layer of a conductive paste such as a silver paste. In order to impart heat resistance and moisture resistance, the element of this niobium capacitor is generally formed with a polymer sealing material such as an epoxy resin or a phenol resin, sealed, and put to practical use.

In the method for manufacturing a niobium capacitor according to the present invention, the dielectric oxide film layer is formed at a temperature of 100 ° C. to 1400 ° C.
It is characterized by exposure to high temperature of ℃. The process of exposing to high temperature
The temperature and temperature may vary depending on the stability of the other materials constituting the niobium capacitor, for example, the materials used for the semiconductor layer, the conductor layer, and the like, to the heat after forming the dielectric oxide film layer. In a niobium capacitor, an organic semiconductor layer such as polypyrrole is preferably used. In this case, it is particularly preferable to expose the sintered body having the oxide film formed thereon to heat after the oxide film is formed and before the organic semiconductor layer is formed. The temperature at which the dielectric oxide film layer is exposed is preferably equal to or higher than the formation temperature and equal to or lower than the melting point of the oxide film. For example, a temperature of 100 ° C to 1400 ° C is preferable, 150 ° C to 1200 ° C is more preferable,
1000 ° C. is particularly preferred. When heating after forming the organic semiconductor layer (before forming the conductor layer), the temperature is preferably from 100C to 350C, particularly preferably from 150C to 300C.
When heating after forming the conductor layer (before encapsulation), 10
The temperature is preferably from 0 ° C. to 300 ° C., particularly preferably higher than the curing temperature of the resin used for the exterior, and not higher than 270 ° C. For example, when using a resin having a curing temperature of 140 ° C., 150 ° C. to 270
C is particularly preferred. The reason for setting the temperature higher than the curing temperature of the resin used for the exterior is to reduce the influence of thermal stress at the time of sealing the resin, to prevent the occurrence of cracks inside the semiconductor layer, and to prevent the leakage current value from increasing. it is conceivable that.

The atmosphere exposed to the high temperature may be in the air or in an atmosphere of an inert gas such as He, Ne, or Ar. Further, there is no problem if the reaction is performed under any of reduced pressure, normal pressure, and increased pressure. In particular, when a temperature of 350 ° C. or higher is used, it is preferable that the pressure be reduced in the inert gas atmosphere. In any case, the holding time at a high temperature is several seconds to several tens of hours. After exposing the dielectric oxide film layer to heat, electrolytic oxidation can be further performed to stabilize the dielectric oxide film layer.

The niobium sintered body used in the present invention will be described. The niobium sintered body may be a niobium alloy sintered body, as long as the dielectric oxide film layer mainly composed of niobium oxide is formed. In the present invention, the niobium alloy includes a solid solution of an alloy component other than niobium.

For example, as the niobium sintered body, a niobium simple sintered body can of course be preferably used, but a niobium sintered body is obtained by treating a part of the niobium sintered body by at least one of nitriding, boriding, carbonizing and sulfurizing. It may be. The amount of the bond, that is, the sum of the contents of nitrogen, boron, carbon, and sulfur varies depending on the particle size of the fine powder used for producing the sintered body, the specific surface area of the sintered body, the shape of the sintered body, and the like, but is 50 mass ppm. ~ 20
0000 mass ppm, preferably 200 mass ppm
２０20,000 ppm by mass.

The other alloy components of the niobium alloy sintered body include lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, radium, scandium, yttrium, lanthanum, cerium, praseodymium, Neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, titanium, zirconium, hafnium, vanadium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, Rhodium, iridium, nickel, palladium, platinum, copper,
Selected from the group consisting of silver, gold, zinc, cadmium, mercury, boron, aluminum, gallium, indium, thallium, carbon, silicon, germanium, tin, lead, phosphorus, arsenic, antimony, bismuth, selenium, tellurium, polonium, and astatine At least one of them. The sum of the contents is 50 mass pp, although it depends on the contained elements.
m to 400,000 ppm by mass is preferred, and from the LC characteristics thereof, 100 ppm to 50,000 ppm by mass is particularly preferred. Furthermore, a part of these niobium alloy sintered bodies was
It may be nitrided, borated, carbonized, or sulfurized. The amount of the bond, that is, the sum of the contents of nitrogen, boron, carbon, and sulfur varies depending on the other alloy component and the content thereof, but is from 50 mass ppm to 20,000 mass ppm, preferably from 200 mass ppm to 5 mass ppm. 2,000 mass ppm.

The dielectric oxide film layer formed on the surface of the niobium sintered body may be an oxide layer of the sintered body itself provided on the surface layer portion of the sintered body, or may be formed on the surface of the sintered body. May be used, but it is particularly preferable that the layer contains a niobium sintered body oxide.
In particular, an oxide layer containing niobium oxide as a main component is preferable. In any case, a conventionally known method can be used as a method for providing an oxide layer. For example, when a dielectric mainly composed of niobium oxide is formed by electrolytic oxidation (also referred to as electrolytic formation or simply formation), Japanese Patent Application Laid-Open No. 2000-2000
As shown in Japanese Patent No. 182899, chemical conversion may be performed in a 0.1% phosphoric acid aqueous solution.

The composition of the semiconductor layer used in the present invention and the method of forming it are not particularly limited, but at least one compound selected from an electrolytic solution, an organic semiconductor and an inorganic semiconductor known in the aluminum electrolytic capacitor industry. can give.

Specific examples of the electrolyte include a mixture of dimethylformamide and ethylene glycol in which 5% by mass of an isobutyltripropylammonium borotetrafluorolide electrolyte is dissolved, and propylene carbonate in which 7% by mass of tetraethylammonium borotetrafluorolide is dissolved. A mixed solution of ethylene glycol and the like can be mentioned.

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, and the following general formula: (1) or (2)

[0017]

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[0018]

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(Wherein, R ^{1 to} R ⁴ may be the same or different from each other, and each represents a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 10 carbon atoms,
A monovalent group selected from the group consisting of an alkoxy group or an alkyl ester group, a halogen atom, a nitro group, a cyano group, a primary, secondary or tertiary amino group, a CF ₃ group, a phenyl group and a substituted phenyl group. The hydrocarbon chains of R ¹ and R ² and R ³ and R ⁴ may be bonded to each other at any position to form a saturated or unsaturated at least one or more 3- to 7-membered ring together with the carbon atom substituted by such a group. A divalent chain forming a cyclic structure of a saturated hydrocarbon may be formed. The cyclic bond chain includes carbonyl, ether, ester, amide,
Sulfide, sulfcarbonyl, ether, ester,
An amide, sulfide, sulfinyl, sulfonyl, or imino bond may be included at any position. X represents an oxygen, sulfur or nitrogen atom, R ⁵ is present only when X is a nitrogen atom, and independently represents hydrogen or a linear or branched saturated or unsaturated alkyl group having 1 to 10 carbon atoms. Represent. Examples of the polymer containing a repeating unit represented by the formula (1) include an organic semiconductor mainly composed of a conductive polymer doped with a dopant. Among them, polypyrrole and poly (3,4-ethylenedioxythiophene) are particularly preferred.

Examples of the inorganic semiconductor include an inorganic semiconductor containing lead dioxide or manganese dioxide as a main component, and an inorganic semiconductor made of triiron tetroxide. Such semiconductors may be used alone or in combination of two or more.

When the other electrode is solid, for example, a conductive paste such as a carbon paste and a silver paste is sequentially laminated on the other electrode to form a conductive layer. As the conductive paste in the present invention, one or more conventionally known conductive pastes can be used.

The exterior to be performed next is, for example, an epoxy resin,
Resin exterior with known polymer resin such as phenolic resin, dipping, casting, molding,
It is performed by a known method such as potting and powder coating.

As described above, after forming the dielectric oxide film layer on the niobium sintered body and the niobium alloy sintered body, 100 ° C. to 1 ° C.
The capacitor manufactured using the operation of exposing the dielectric oxide film layer to a temperature of 400 ° C. has a stable dielectric oxide film layer, a small change in capacitance due to DC bias application, a small LC value, and a high heat resistance. It is a highly reliable capacitor. Further, when the capacitor of the present invention is used, a smaller capacitor product can be obtained as compared with a conventional capacitor having the same capacity.

The capacitor of the present invention having such characteristics can be applied to, for example, a bypass capacitor and a coupling capacitor which are frequently used in analog circuits and digital circuits, and also to a conventional tantalum capacitor.

In general, such a capacitor is frequently used in an electronic circuit. Therefore, if the capacitor of the present invention is used,
Restrictions on the arrangement of electronic components and exhaust heat are relaxed, and a highly reliable electronic circuit can be accommodated in a smaller space than before.

Further, by using the capacitor of the present invention,
It is possible to obtain smaller and more reliable electronic devices than before, such as computer peripheral devices such as computers and PC cards, mobile devices such as mobile phones, home appliances, in-vehicle devices, artificial satellites, and communication devices.

[0027]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In each example, the capacitance and leakage current value of the chip-processed capacitor were measured by the following methods.

(1) Measurement of Capacitance of Capacitor At room temperature, an LCR measuring device (precision LCR meter HP4284A type) was connected between terminals of the manufactured chip, and DC was measured at 120 Hz.
The capacity when a bias of 1.5 V was applied was taken as the capacity of the capacitor processed by the chip. Further, in order to further clarify the improvement of the performance with respect to the application of the DC bias, the change in CV represented by the following equation was defined as “CV residual rate”. CV residual ratio (%) = (CV with 1.5 V DC bias applied)
Value / No applied CV value) × 100

(2) Measurement of leakage current of capacitor At room temperature, the rated voltage value (2.5 V, 4 V, 6.3)
V, 10 V, 16 V, 25 V, etc.), a DC voltage (6.3 V) close to about 1/3 to about 1/4 of the formation voltage (DC, 20 V) at the time of producing the dielectric material, The current value measured after the application was continued for one minute in between was defined as the leakage current value of the capacitor processed into the chip.

Example 1: 100 g of niobium ingot was added to S
The vessel was placed in a container made of US304, and hydrogen was continuously introduced at 400 ° C. for 10 hours. After cooling, the hydrogenated niobium mass is
Put in an SUS304 pot containing S balls and put 10
Crushed for hours. Next, a 20 volume% slurry of this hydride and water and a zirconia ball were put into a SUS304 spike mill and wet-pulverized at 10 ° C. or lower for 7 hours. After centrifugal sedimentation of this slurry, decantation was performed to obtain a pulverized product. 1.33 × 1 crushed material
Drying was performed under the conditions of 0 ² Pa and 50 ° C. Subsequently, the niobium hydride powder was dehydrogenated by heating at 1.33 × 10 ⁻² Pa and 400 ° C. for 1 hour. The average particle size of the prepared niobium powder is 0.8
μm. The obtained niobium powder was granulated at 1000 ° C. under a reduced pressure of 4 × 10 ⁻³ Pa. Thereafter, the granulated mass was pulverized to obtain a niobium granulated powder having an average particle size of 100 μm, and was heated at 300 ° C. for 4 hours in a nitrogen stream to be nitrided.

The niobium granulated powder thus obtained was molded together with a 0.3 mmφ niobium wire to obtain a powder of about 0.3 c.
m × 0.18 cm × 0.45 cm (approximately 0.1
g) was prepared.

Next, these compacts were left under a reduced pressure of 4 × 10 ⁻³ Pa at 1200 ° C. for 30 minutes to obtain sintered compacts. The obtained sintered body is placed in a 0.1% phosphoric acid aqueous solution,
A dielectric oxide film layer was formed on the surface by forming at a temperature of 80 ° C. for 1000 minutes at a voltage of 20 V.

Next, the sintered body having the dielectric layer formed on the surface was exposed to a temperature of 285 ° C. for 30 minutes under atmospheric pressure at atmospheric pressure. After cooling to room temperature, formation was further carried out in a 0.1% phosphoric acid aqueous solution at a temperature of 80 ° C. for 200 minutes at a voltage of 20 V. Subsequently, a 10% aqueous solution of ammonium persulfate and 0.1 ml of anthraquinonesulfonic acid were placed on the dielectric oxide film layer.
After an equal amount of a 5% aqueous solution was brought into contact with the mixture, an operation of contacting with pyrrole vapor was performed at least five times to form an organic semiconductor layer made of polypyrrole.

Subsequently, a carbon layer and a silver paste layer were sequentially laminated thereon. Next, after mounting the lead frame, Nitto Pernox Co., Ltd. powder epoxy resin PCE
Powder coating was performed five times at 273 ° C. at 155 ° C.
The composition was cured at a temperature of 2 ° C. for 2 hours and sealed with an exterior to produce a chip-type capacitor. Average of capacitance and LC value of this capacitor (n =
100 each) are shown in Table 1. The LC value was 6.3 V,
This is the value when applying for 1 minute.

Examples 2 to 5 In the same manner as in Example 1, niobium alloy sintered bodies were obtained from niobium alloy ingots of the respective alloy types shown in Table 1 as starting materials. After the dielectric oxide film is formed, it is exposed to the temperature shown in Table 1,
After forming the organic semiconductor layer and the conductor layer, a chip capacitor was manufactured. Table 1 shows the average of the capacitance and the LC value of this capacitor (n = 100 each). In addition, LC value is 6.
It is a value when 3 V is applied for one minute.

Example 6 A niobium zinc alloy powder having an average particle diameter of 0.8 μm was obtained from a niobium zinc alloy containing 1000 mass ppm of zinc as a starting material by hydrogenation, pulverization and dehydrogenation in the same manner as in Example 1. . The obtained niobium zinc alloy powder was dried under reduced pressure of 4 × 10 ⁻³ Pa,
Granulated at 50 ° C. Thereafter, the granulated mass was crushed to obtain a niobium granulated powder having an average particle size of 120 μm.

The niobium zinc granulated powder obtained in this manner was molded together with a 0.3 mmφ niobium wire to obtain a powder of about 0.1 mm.
A 3 cm x 0.18 cm x 0.45 cm molded body (approximately
1g) was prepared.

Next, these compacts were left under a reduced pressure of 4 × 10 ⁻³ Pa at 1250 ° C. for 30 minutes to obtain sintered compacts. The obtained sintered body is placed in a 0.1% phosphoric acid aqueous solution,
A dielectric oxide film layer was formed on the surface by forming at a temperature of 80 ° C. for 1000 minutes at a voltage of 20 V.

Subsequently, the sintered body having the dielectric layer formed on the surface was exposed to a temperature of 500 ° C. for 30 minutes under a reduced pressure of 4 × 10 ⁻³ Pa. After cooling to room temperature, the sintered body was immersed in an aqueous solution (solution 1) containing 25% by mass of ammonium persulfate, pulled up, dried at 80 ° C. for 30 minutes, and then sintered with 3,4-ethylenedioxy. After being immersed in an isopropanol solution (solution 2) containing 18% by mass of thiophene, it was pulled up and left in an atmosphere of 100 ° C. for 10 minutes to carry out oxidative polymerization. This was immersed again in solution 1 and further treated as described above. The operation from immersion in the solution 1 to oxidative polymerization was repeated eight times, and then repeated with 50 ° C. warm water.
After washing for 0 minutes and drying at 100 ° C. for 30 minutes, an organic semiconductor layer made of poly (3,4-ethylenedioxythiophene) was formed.

Subsequently, a carbon layer and a silver paste layer were sequentially laminated thereon. Next, after mounting a lead frame, an epoxy resin XNR12 manufactured by Ciba-Geigy Japan
13, dipping was performed once, curing was performed at 150 ° C. for 2 hours, and sealing was performed to prepare a chip capacitor. Average of the capacitance and LC value of this chip type capacitor (n
= 50 each) are shown in Table 1. The LC value was 6.
It is a value when 3 V is applied for one minute.

Examples 7 and 8 In the same manner as in Example 6, niobium alloy sintered bodies were obtained from niobium alloy ingots of the respective alloy types shown in Table 1 as starting materials. This was exposed to the temperatures shown in Table 1 after the formation of the dielectric oxide film, and after forming the organic semiconductor layer and the conductor layer, a chip capacitor was produced. The capacitance of this capacitor and LC
Table 1 shows the average of the values (n = 100 each). In addition, LC
The value is a value when 6.3 V is applied for 1 minute.

Example 9 A niobium-antimony alloy powder having an average particle diameter of 0.8 μm was obtained from a niobium-antimony alloy containing 10000 mass ppm of antimony as a starting material in the same manner as in Example 1. . The obtained niobium antimony alloy powder was
Granulation was performed at 1100 ° C. under a reduced pressure of × 10 ⁻³ Pa. Thereafter, the granulated mass was pulverized to obtain a niobium antimony granulated powder having an average particle size of 95 μm.

The niobium-antimony granulated powder thus obtained is molded together with a niobium wire having a diameter of 0.3 mm to form a compact (about 0.1 g) of about 0.3 cm × 0.18 cm × 0.45 cm. Then, these compacts were reduced to 4 × 10 ^-3
It was left at 1250 ° C. for 30 minutes under a reduced pressure of Pa to obtain a sintered body. The obtained sintered body was formed in a 0.1% aqueous solution of phosphoric acid at a temperature of 80 ° C. for 1000 minutes at a voltage of 20 V to form a dielectric oxide film layer on the surface.

Next, immersion in a 60% aqueous manganese nitrate solution and subsequent heating at 190 ° C. for 120 minutes were repeated to form a manganese dioxide layer as a semiconductor layer on the dielectric oxide film. Subsequently, the substrate was exposed to a temperature of 400 ° C. for 30 minutes in an Ar atmosphere. After cooling to room temperature, a carbon layer,
Silver paste layers were sequentially laminated. Next, after mounting a lead frame, transfer molding was performed with an epoxy resin MP series manufactured by Nitto Denko Corporation, and the package was cured at 190 ° C. for 30 minutes to seal the exterior, thereby producing a chip-type capacitor. Table 1 shows the average of the capacitance and the LC value (n = 100 each) of the chip type capacitor. The LC value is a value when 6.3 V is applied at room temperature for 1 minute.

Examples 10 to 11 In Example 10, a niobium sintered body and a niobium zirconium gallium alloy sintered body were obtained in the same manner as in Example 1 and Example 11 in Example 2. After the formation of the dielectric oxide film, a semiconductor layer was formed in the same manner as in Example 9, and then exposed to the temperature shown in Table 1, and a conductor layer was formed. The average of the capacitance and LC value of this capacitor (n
= 100 each) are shown in Table 1. The LC value was 6.3.
V is a value when one minute is applied.

Comparative Examples 1 to 3 Comparative Example 1 is Example 1, Comparative Example 2 is Example 6, and Comparative Example 3 is that the sintered body formed with the dielectric oxide film layer obtained in Example 9 is exposed to heat. Instead, the semiconductor layer, the conductor layer, and the exterior sealing with an epoxy resin were sequentially performed in the same manner as in each example, to produce a chip-type capacitor. The capacitance of this capacitor and L
Table 1 shows the average of the C values (n = 100 each). Note that L
The C value is a value when 6.3 V is applied for one minute.

[0047]

[Table 1]

[0048]

According to the present invention, there is provided a capacitor having good high-temperature life characteristics and a small bias change, particularly a niobium solid electrolytic capacitor having a large capacity per unit mass and a small leakage current value.

Continued on the front page (72) Inventor Hiroshi Fukunaga 5-1 Okawacho, Kawasaki City, Kanagawa Prefecture Showa Denko R & D Center

Claims (10)

[Claims] In a method for manufacturing a niobium capacitor, an oxide film is formed on a surface of a niobium sintered body, a semiconductor layer is formed on the oxide film, and a conductor layer is formed on the semiconductor layer. A sintered body in which an oxide film is formed on the surface of the sintered body and no semiconductor layer is formed is heated at 100 ° C. to 1400 ° C.
A method for producing a niobium capacitor, characterized by exposing to a temperature in the range of: 2. A method for manufacturing a niobium capacitor, comprising: forming an oxide film on a surface of a niobium sintered body, an organic semiconductor layer on the oxide film, and a conductor layer on the organic semiconductor layer, and packaging and sealing the niobium capacitor. An oxide film is formed on the surface of the niobium sintered body, and an organic semiconductor layer is formed on the oxide film, and the sintered body without the conductor layer is exposed to a temperature in the range of 100 ° C to 350 ° C. Manufacturing method for niobium capacitors. 3. A method for manufacturing a niobium capacitor in which an oxide film is formed on a surface of a niobium sintered body, an organic semiconductor layer is formed on the oxide film, and a conductor layer is formed on the organic semiconductor layer, and the package is covered with a resin and sealed. Wherein an oxide film, a semiconductor layer, and a conductor layer are formed on the surface of a niobium sintered body, and the sintered body that is not sealed with a resin is exposed to a temperature in a range of 100 ° C to 300 ° C. Manufacturing method for a niobium capacitor. 4. The method for producing a niobium capacitor according to claim 1, wherein the niobium sintered body contains 50 mass ppm to 400,000 mass ppm of one or more elements other than niobium. 5. The niobium sintered body is a niobium alloy sintered body, wherein lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, radium, scandium, Yttrium, lantern, cerium, praseodymium, neodymium, samarium,
Europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, titanium, zirconium, hafnium, vanadium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel,
Palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, boron, aluminum, gallium, indium, thallium, carbon, silicon, germanium, tin, lead, phosphorus,
At least one selected from the group consisting of arsenic, antimony, bismuth, selenium, tellurium, polonium, and astatine
50 mass ppm to 40 as a total of the contents of the seed elements
The method for producing a niobium capacitor according to any one of claims 1 to 4, wherein the niobium capacitor includes 0000 mass ppm. 6. The niobium sintered body according to claim 1, wherein said niobium sintered body contains at least one element selected from the group consisting of boron, nitrogen, carbon and sulfur in an amount of 50 ppm to 200,000 ppm. 4. The method for producing a niobium capacitor according to claim 1. 7. A method for manufacturing a niobium capacitor, wherein a dielectric oxide film is formed at a temperature of 100.degree.
A method for manufacturing a niobium capacitor, comprising sealing after exposing to a temperature in the range of 0 ° C. 8. A capacitor obtained by the manufacturing method according to claim 1. 9. An electronic circuit using the capacitor according to claim 8. 10. An electronic device using the capacitor according to claim 8.