JP4049804B2 - Reaction vessel for manufacturing capacitor element, method for manufacturing capacitor element, and method for manufacturing capacitor - Google Patents

Description

  The present invention relates to a reaction container for manufacturing a capacitor element that achieves a stable capacity appearance rate, a method for manufacturing a capacitor element, and a method for manufacturing a capacitor.

  Capacitors used in CPU (Central Processing Unit) circuits used in personal computers, etc. have high capacity and low ESR (equivalent) to suppress voltage fluctuation and reduce heat generation when passing through high ripple. Series resistance).

Generally, a plurality of aluminum solid electrolytic capacitors and tantalum solid electrolytic capacitors are used as capacitors used in the CPU circuit.
In such a solid electrolytic capacitor, an aluminum foil having fine pores in the surface layer or a sintered body of tantalum powder having fine pores inside is used as one electrode (conductor), and the surface layer of the electrode is The dielectric layer is formed and the other electrode (usually a semiconductor layer) provided on the dielectric layer.

  As a method for forming a semiconductor layer of a capacitor using the semiconductor layer as the other electrode, for example, Japanese Patent No. 1868722 (Patent Document 1), Japanese Patent No. 1985056 (Patent Document 2) and Japanese Patent No. 2054506 There is a method of forming by an energization method described in (Patent Document 3). In each case, a conductor provided with a dielectric layer on the surface is dipped in a semiconductor layer forming solution, and a voltage is applied between the external electrode (cathode) prepared in the semiconductor layer forming solution with the conductor side as an anode (current is applied). This is a method of forming a semiconductor layer by flowing.

  Japanese Patent Laid-Open No. 3-22516 (Patent Document 4; related application US501727) discloses a method of forming a semiconductor layer by flowing a current obtained by superimposing a DC bias current on an alternating current through a conductor provided with a dielectric layer. Are listed. In Japanese Patent Laid-Open No. 3-163816 (Patent Document 5), a conductor is brought into contact with a chemical polymerization layer provided on a dielectric layer, and a semiconductor layer is formed on the chemical polymerization layer by electrolytic polymerization using the conductor as an anode. How to do is described. These methods have a problem when a semiconductor layer is formed on a plurality of conductors at the same time. That is, the method described in Patent Document 4 has a problem in that a semiconductor layer is formed on the cathode side, and the degree of formation of the semiconductor layer changes as the energization time elapses. There was no guarantee that current would flow. Further, in the method described in Patent Document 5, since a current is applied using a conductor provided outside as an anode, there is no guarantee that a uniform semiconductor layer is formed inside each conductor. In particular, in the case of a conductor having a small internal pore and a large shape, it was a big problem.

Japanese Patent No. 1868722 Japanese Patent No. 1985056 Japanese Patent No. 2054506 JP-A-3-22516 JP-A-3-163816

  When the semiconductor layer is formed on the conductor formed with the dielectric layer by the energization method, there was no problem when the semiconductor layer was formed on several conductors, but at an industrial level, for example, once. When forming a semiconductor layer on more than 100 conductors, each conductor is not necessarily homogeneous, and the formation speed of the semiconductor may vary depending on the conductor, so the semiconductor layers are formed on many conductors at the same time. In this case, the value of the current flowing through each conductor is not constant, and there are cases where it is difficult to fabricate a capacitor having a stable capacity due to uneven formation of the semiconductor layer of the fabricated capacitor.

Thus, the present inventors have previously proposed a reaction vessel in which small reaction vessels corresponding to individual conductors are assembled (see WO2006 / 028286 pamphlet). In this collective reaction vessel, Since the reaction liquid is consumed and adhesion to the conductor, drying, and the like proceed, changes in the liquid level of each small reaction vessel over time are not necessarily uniform. For this reason, it has been difficult to use repeatedly without adjusting the liquid level of the solution in each small reaction vessel.
Accordingly, it is an object of the present invention to propose a reaction vessel for manufacturing a capacitor element that can easily ensure the uniformity of the liquid surface level and can supply electricity more stably.

  In order to solve the above problems, the present inventors have made a plurality of electrodes and rooms corresponding to individual conductors in the reaction vessel (with cathodes and other rooms electrically connected to individual constant current sources, respectively). The above problem has been solved by a reaction vessel in which a chamber provided with at least one passage through which an electrolytic solution can move is provided, and current flowing to another chamber can be reduced during energization for forming a semiconductor layer.

That is, the present invention provides the following reaction container for manufacturing a capacitor element, a method for manufacturing a capacitor element, a capacitor element, and a capacitor.
1. A reaction vessel for forming a semiconductor layer by an energization method by simultaneously immersing a plurality of conductors having a dielectric layer formed on the surface thereof in an electrolytic solution in a reaction vessel, wherein each conductor is formed in the reaction vessel. A corresponding plurality of cathodes and chambers are provided, each cathode being electrically connected to an individual constant current source, and each chamber having at least one electrolyte moveable between the other chambers A reaction vessel for producing a capacitor element, characterized in that a passage is provided.
2. 2. The reactor for producing a capacitor element as described in 1 above, wherein the passage is a hole opened in the wall surface of the room, and the size (diameter) thereof is 0.1 to 10 mm.
3. 3. The reaction container for producing a capacitor element according to 1 or 2, wherein the passage is opened in a slit shape on the wall surface of the room, and the slit gap is 0.1 mm to 10 mm.
4). 4. The reaction container for producing a capacitor element according to any one of 1 to 3, wherein a cathode is provided on the bottom surface of each room.
5. 5. The reaction container for producing a capacitor element according to any one of 1 to 4, wherein a cathode is provided on a wall surface of each room.
6). 2. The reaction container for manufacturing a capacitor element according to 1 above, wherein the plurality of constant current sources are composed of a plurality of constant current diodes, each cathode is electrically connected, and each anode is connected to the cathode.
7). 7. Each said cathode is arrange | positioned inside the bottom part of reaction container, each constant current diode is arrange | positioned outside the reaction container, and the cathodes of each constant current diode are electrically connected to each other and are collected by the terminal. Reaction vessel for manufacturing capacitor elements.
8). The bottom of the reaction vessel for capacitor element production is made of an insulating substrate, each cathode is provided on the inner surface of the reaction vessel of the insulating substrate, and a constant current source corresponding to each cathode is provided on the outer surface thereof, 8. The reaction container for producing a capacitor element according to any one of 1 to 7, wherein both are electrically connected.
9. 9. The reaction container for producing a capacitor element according to any one of 1 to 8 above, wherein the cathode is a film metal material.
10. 10. A method for producing a capacitor element, comprising using the reaction container for producing a capacitor element according to any one of 1 to 9 above.
11. A plurality of conductors having a dielectric layer are immersed in the electrolytic solution in a reaction vessel for manufacturing a capacitor element filled with the electrolytic solution, and each cathode provided in the reaction vessel with the conductive material side as an anode serves as a cathode. When the step of forming the semiconductor layer on the dielectric layer by a current application method is performed a plurality of times, the step is repeatedly performed without adjusting the liquid level of each chamber of the reaction container for manufacturing the capacitor element. Manufacturing method of capacitor element.
12 A method for producing a capacitor for sealing the capacitor element obtained by the method of 10 or 11.

  Examples of the conductor used in the present invention include metals, inorganic semiconductors, organic semiconductors, carbon, a mixture of at least one of these, and a laminate in which these conductors are stacked on the surface layer.

  Examples of inorganic semiconductors include metal oxides such as lead dioxide, molybdenum dioxide, tungsten dioxide, niobium monoxide, tin dioxide, and zirconium monoxide, and organic semiconductors include polypyrrole, polythiophene, polyaniline, and polymer skeletons Examples thereof include conductive polymers such as substitution products and copolymers, complexes of tetracyanoquinodimethane (TCNQ) and tetrathiotetracene, and low-molecular complexes such as TCNQ salts. Moreover, as an example of the laminated body which laminated | stacked the conductor on the surface layer, the laminated body which laminated | stacked the said conductor on paper, insulating polymer, glass, etc. is mentioned.

  When a metal is used as the conductor, a part of the metal may be used after being subjected to at least one treatment selected from carbonization, phosphation, boronation, nitridation, and sulfidation.

  The shape of the conductor is not particularly limited, and may be used as a foil shape, a plate shape, a rod shape, a shape in which the conductor itself is powdered, molded, or sintered after molding. The conductor surface may be processed by etching or the like to have fine pores. When the conductor is powdered to form a molded body or a sintered shape after molding, fine pores should be provided in the interior after molding or sintering by appropriately selecting the pressure during molding. Can do.

  The lead can be directly connected to the conductor. However, if the conductor is powdered and formed into a molded body shape or a shape that is sintered after molding, the lead wire (or lead) prepared separately at the time of molding is used. It is also possible to form a part of the foil) together with the conductor, and to place the lead-out lead wire (or lead foil) outside the molding as a lead-out lead for one electrode of the capacitor.

  Alternatively, a semiconductor layer which will be described later may be left without forming a part of the conductor to form an anode part. In order to prevent the semiconductor layer from creeping up at the boundary between the anode portion and the semiconductor layer forming portion, an insulating resin may be adhered and cured in a headband shape.

  Preferred examples of the conductor used in the present invention include an aluminum foil whose surface is etched, tantalum powder, niobium powder, alloy powder mainly containing tantalum, alloy powder mainly containing niobium, and niobium monoxide powder. An example is a sintered body in which a large number of fine pores are present inside a powder obtained by sintering after molding.

As a dielectric layer formed on the surface of the conductor used in the present invention, the main component is at least one selected from metal oxides such as Ta ₂ O ₅ , Al ₂ O ₃ , TiO ₂ , and Nb ₂ O _5. Conventionally known dielectric layers in the field of dielectric layers, ceramic capacitors, and film capacitors. In the case of a dielectric layer mainly composed of at least one selected from the former metal oxides, a capacitor obtained by forming the dielectric layer by forming the conductor having the metal element of the metal oxide has a polarity. Electrolytic capacitor with Examples of conventionally known dielectric layers for ceramic capacitors and film capacitors include dielectric layers described in Japanese Patent Application Laid-Open Nos. 63-29919 and 63-34917 by the present applicant. A plurality of conventionally known dielectric layers may be laminated and used with a dielectric layer mainly composed of at least one selected from metal oxides, ceramic capacitors, and film capacitors. Alternatively, a dielectric layer containing at least one selected from metal oxides as a main component, or a dielectric layer obtained by mixing a conventionally known dielectric with a ceramic capacitor or a film capacitor may be used.

A specific example for forming a dielectric layer by chemical conversion will be described.
A plurality of long metal plates with a plurality of conductors connected at equal intervals are arranged in a metal frame with the direction aligned in parallel, and conductive with the anode part or part of the lead wire (lead foil) in a separately prepared chemical bath A dielectric layer is formed on the surface layer of the conductor by immersing the body in a chemical conversion solution, applying a voltage between the metal frame side to the anode and a cathode plate in the chemical conversion tank for a predetermined time, lifting, washing and drying. .

  On the other hand, the other electrode of the capacitor obtained in the present invention includes at least one compound selected from an organic semiconductor and an inorganic semiconductor. However, it is important to form the compound by an energization method described later. is there.

  Specific examples of the organic semiconductor include an organic semiconductor composed of benzopyrroline tetramer and chloranil, an organic semiconductor mainly composed of tetrathiotetracene, an organic semiconductor mainly composed of tetracyanoquinodimethane, and the following general formula (1) Or the organic semiconductor which has as a main component the conductive polymer which doped the dopant to the polymer containing the repeating unit shown by (2) is mentioned.

In the formulas (1) and (2), R ^{1 to} R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and X is oxygen, sulfur or Represents a nitrogen atom, 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 It may be.

  Furthermore, in the present invention, the polymer containing a 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, R ⁶ and R ⁷ are each independently a hydrogen atom, a linear or branched saturated or unsaturated alkyl group having 1 to 6 carbon atoms, or an alkyl group thereof bonded to each other at an arbitrary position. And a substituent that forms 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. A dopant is not specifically limited, A well-known dopant can be used.

  Preferable examples of the dopant include compounds having a sulfonic acid group. Examples of such compounds include benzene sulfonic acid, toluene sulfonic acid, naphthalene sulfonic acid, anthracene sulfonic acid, benzoquinone sulfonic acid, naphthoquinone sulfonic acid and anthraquinone sulfonic acid having sulfonic acid having a aryl group, butyl sulfonic acid, hexyl sulfonic acid and Various polymers (polymerization degree 2 to 200) sulfonic acid such as sulfonic acid having alkyl group such as cyclohexyl sulfonic acid, polyvinyl sulfonic acid, salts of these sulfonic acids (ammonium salt, alkali metal salt, alkaline earth metal salt, etc.) Can be cited as a representative example. These compounds may have various substituents, and a plurality of sulfonic acid groups may exist. A plurality of dopants may be used simultaneously.

  Examples of the polymer containing the repeating unit represented by the formulas (1) to (3) include polyaniline, polyoxyphenylene, polyphenylene sulfide, polythiophene, polyfuran, polypyrrole, polymethylpyrrole, and substituted derivatives and copolymers thereof. Etc. Of these, polypyrrole, polythiophene, and substituted derivatives thereof (for example, poly (3,4-ethylenedioxythiophene)) are preferable.

Specific examples of the inorganic semiconductor include at least one compound selected from molybdenum dioxide, tungsten dioxide, lead dioxide, manganese dioxide and the like.
When the organic semiconductor and the inorganic semiconductor have a conductivity in the range of 10 ⁻² to 10 ³ S / cm, the ESR value of the manufactured capacitor is preferably reduced.

  The semiconductor layer described above is formed by a pure chemical reaction (solution reaction, gas phase reaction, solid-liquid reaction, and combinations thereof), formed by an energization method, or a combination of these methods. In the invention, the energization method is adopted at least once in the semiconductor layer forming step. Further, when the semiconductor layer is formed by the energization method, the object of the present invention is achieved by performing energization at least once by a constant current power source (constant current source) during energization.

  As the constant current source, it is only necessary to achieve a constant current circuit capable of energizing the conductor having the dielectric layer on the surface with a constant current. For example, it is preferable to use a constant current diode with a simple circuit and a reduced number of parts. The constant current diode may be composed of a field effect transistor as well as a commercially available constant current diode. Examples of other constant current sources include transistors using transistors, ICs, and three-terminal regulators.

  Hereinafter, an example using a constant current diode as a constant current source will be described, but the constant current source is not limited to this example.

  The reaction vessel for simultaneously producing a plurality of capacitor elements according to the present invention is provided with a cathode plate inside each room of the reaction vessel, and each cathode plate and a current sink type constant current source are connected. It consists of a structure, The channel | path which can move a solution is provided in the other room, It is characterized by the above-mentioned. A metal frame in which a plurality of conductors on which the dielectric layer is formed as described above is formed is arranged on the upper part of the reaction container for manufacturing the capacitor element of the present invention filled with the electrolyte for forming the semiconductor layer. A plurality of connected conductors are installed in individual rooms in the reaction vessel, and a constant current is applied to the metal frame and the cathode. This current forms a semiconductor layer on the dielectric layer of the conductor. The current value may be adjusted according to a desired value of the size of the conductor and the amount of semiconductor to be formed.

  When the constant current source is composed of a constant current diode, each constant current diode is arranged outside the individual chamber of the reaction vessel, and there is no crossing with the cathode plate arranged inside the bottom of the reaction vessel. This is preferable because it can be downsized. In this case, the hole of the reaction vessel by the connection wiring between the cathode plate inside and outside the reaction vessel and the constant current diode can be closed (sealed) with resin or the like.

Hereinafter, an example of a specific embodiment of the present invention will be described with reference to the accompanying drawings.
In the following example, the shape of each room is described as a rectangular cylindrical body, but each room may be provided in a shape and position that can accommodate each of a plurality of conductors connected to a metal frame. (For example, a cylindrical body having a hexagonal bottom surface). Moreover, you may provide a space | gap between each room.
FIG. 1 shows a schematic side sectional view of a reaction vessel (1) for producing a capacitor element, FIG. 2 shows a plan view (surface view) of a preferred arrangement example of a cathode plate and a constant current diode of the reaction vessel, and FIG. Similarly, a back view is shown.
A film-like metal material formed on one side of an insulating substrate by a printing technique is used as a cathode plate (circular in the example shown), and a constant current diode (3) is placed at a predetermined place printed on the back surface through a through hole of the insulating substrate. And a structure in which the through-hole portion is closed with an insulating resin such as an epoxy resin. The through-hole structure is preferable because printed wiring is provided inside the through-hole, so that electrical connection between the front and back sides can be easily performed. The insulating substrate on which the plurality of cathode plates (2) and the constant current diodes (3) are arranged in this way is used as the bottom of the reaction vessel, and a frame is formed from the insulating resin so as to surround the insulating substrate. The reaction vessel (1) thus prepared can be used.

  Further, in the present invention, a frame (6) having a predetermined height is provided at a predetermined position of the insulating substrate so as to be perpendicular to the substrate, and a plurality of chambers in which each cathode plate is placed in the reaction vessel are prepared. The structure is filled with the electrolyte for forming the layer, and at least one hole is provided for communicating each room. Therefore, in a room surrounded on four sides by another room, it is preferable to provide at least four holes on the wall surface. However, it is not necessary to provide holes between all adjacent rooms as long as the liquid can move substantially between the rooms. The hole may be located below the uppermost surface of the solution to be put in the reaction vessel. The size of the hole is larger than the size that the solution can move to make the liquid level uniform within the practical time range, and smaller than the size that allows the amount of current flowing to other rooms when energized. And The specific hole size varies depending on the size of the reaction vessel, the size of each room, and the range of variation in the desired capacitor characteristic value, and thus is determined by preliminary experiments. Usually, a hole having a size of 0.1 mm to 10 mmφ, preferably 1 mm to 5 mmφ is selected. Within this range, the liquid level in each room becomes uniform in a few seconds to a few minutes, and variations in capacitor characteristics do not increase.

It is preferable that the wall surface of each room be an electrical conductor (electrically connected to the cathode provided at the bottom) so that the electric field in each room does not affect other rooms as much as possible. The shape of the hole is not limited to a round shape as long as the solution can move. For example, a slit shape may be used, and for the same reason as the hole diameter, the gap is preferably 0.1 to 10 mm, and more preferably 1 to 5 mm.
It is preferable that each conductor formed with the above-described dielectric layer is designed to be immersed in a reaction solution having a uniform liquid level, so that a desired current can be reliably supplied to each conductor. Become. A cathode plate that is electrically connected only to the cathode plate on the bottom surface of each room on a part or all of the frame having a predetermined height may be prepared in advance.

  The size of the reaction vessel of the present invention can be appropriately determined according to the volume and number of conductors produced at one time and the size of the cathode plate.

  The individual cathode plates provided in the reaction vessel are electrically insulated from each other, and each cathode plate is designed so that one conductor faces each other. For this reason, it is desirable to make the size of the cathode plate larger than the corresponding surface of the conductor to be used. However, if it is too large, the size of the reaction vessel also becomes large. For this reason, it is preferable that the size of the cathode plate is determined to be a minimum size capable of supplying a current for forming a sufficient semiconductor layer on the conductor by a preliminary experiment. For example, when the lower surface of the conductor is rectangular, the size of the cathode plate is about 1.01 to 3 times, preferably about 1.01 to 1.5 times the rectangular area.

  As the material of the cathode plate, a non-corrosive conductor can be used for the electrolyte for forming the semiconductor layer. For example, iron alloy, copper alloy, tantalum, platinum or the like is used. The cathode plate surface may be plated with at least one layer of a non-corrosive conductor such as nickel, gold, silver, or solder. When such a plating layer is laminated on the surface, corrosive conductors such as copper and aluminum can also be used.

  A plurality of cathode plates can be provided in one room. In this case, for example, two cathode plates may be provided in one room, and both of them may be connected to one constant current source, and two constant current sources are not used. It is preferable to provide one cathode plate having a size capable of entering one room.

  When the constant current source is configured using a constant current diode, for example, each cathode of a plurality of constant current diodes is electrically connected, and the cathode plate is electrically connected in series to the anode of each constant current diode. The thing of the structure connected to is mentioned.

  This will be described in more detail based on the example of the reactor for producing a capacitor element shown in FIG. A plurality of cathode plates (2) exist independently in each room at the bottom of the reaction vessel (1), and the anode of the constant current diode (3) outside the bottom of the reaction vessel is connected to each cathode plate in series. Yes. Each room is provided with a hole through which the solution can freely enter and exit the frame wall that constitutes the room, and the electrolyte for forming the semiconductor layer (not shown) is of equal height so as not to exceed the height of the room. Filled with.

  FIG. 3 is a schematic view of the bottom of the reaction vessel as seen from the outside. A plurality of constant current diodes (3) are arranged in parallel at equal intervals, and the cathode side of each constant current diode is electrically connected to the current collecting terminal (4) on the upper left in the figure. FIG. 2 is a schematic view of the reaction container as viewed from above. A plurality of cathode plates (2) are arranged at equal intervals. The individual cathode plates are insulated from each other and connected to the anodes of the respective constant current diodes of FIG. 3 through through holes (not shown) provided in the same number as the cathode plates at the bottom of the reaction vessel. Each through hole is sealed with an insulating resin or ceramic so that the electrolytic solution in the reaction vessel does not ooze out. In the upper part of the reaction vessel, a metal frame in which a plurality of metal plates having conductors (5) having a dielectric layer formed on the surface are connected at equal intervals and arranged at equal intervals is arranged. Each conductor is immersed one by one in an electrolyte solution that is put in a predetermined amount in each room provided in the reaction vessel.

Next, a method for forming a semiconductor layer by an energization method using the above reaction container for manufacturing a capacitor element will be described.
Each chamber of the reaction vessel is filled with an electrolyte for forming a semiconductor layer so that it does not exceed the height of the chamber, and then placed in a metal frame at equal intervals to form a dielectric layer on the surface. One body is immersed in each room, a metal frame is connected to the anode, a current collecting terminal arranged outside the bottom of the reaction vessel is connected to the cathode of the power source, and a semiconductor layer is formed by an energization method.

Formation of a semiconductor layer in which a raw material that becomes a semiconductor when energized or, in some cases, known dopants (eg, known dopants such as aryl sulfonic acid or salt, alkyl sulfonic acid or salt, various polymer sulfonic acid or salt) are dissolved A semiconductor layer is formed on the dielectric layer by energizing the solution. Since the energization time, the concentration of the semiconductor layer forming solution, pH, temperature, energization current value, and energization voltage value vary depending on the type, size, and mass of the conductor used, the desired thickness of the semiconductor layer, etc. The conditions are determined by It is also possible to energize a plurality of times by changing energization conditions. In addition, in order to repair defects in the dielectric layer formed on the surface of the conductor, a conventionally known re-formation operation is performed at any time during the course (can be performed once or multiple times) and / or finally. Also good.
In addition, a semiconductor layer may be formed by the method of the present invention after an electrical minute defect is formed in a dielectric layer formed on the surface of the conductor layer.

  In the capacitor of the present invention, an electrode layer may be provided on the semiconductor layer formed by the above-described method or the like in order to improve electrical contact with an external lead (for example, a lead frame) of the capacitor.

  The electrode layer can be formed, for example, by solidification of a conductive paste, plating, metal deposition, adhesion of a heat-resistant conductive resin film, or the like. As the conductive paste, silver paste, copper paste, aluminum paste, carbon paste, nickel paste and the like are preferable. These may be used alone or in combination of two or more. When using 2 or more types, they may be mixed or laminated as separate layers. After applying the conductive paste, it is left in the air or heated to solidify. The thickness of the conductive paste after solidification is usually about 0.1 to about 200 μm per layer.

The conductive paste contains conductive powder such as resin and metal as main components, and may contain a solvent for dissolving the resin, a curing agent for the resin, or the like depending on the case. The solvent is scattered when the paste is solidified.
As the resin in the conductive paste, various known resins such as alkyd resin, acrylic resin, epoxy resin, phenol resin, imide resin, fluorine resin, ester resin, imidoamide resin, amide resin, styrene resin, and urethane resin are used. . As the conductive powder, at least one of silver, copper, aluminum, gold, carbon, nickel and alloy powders mainly composed of these metals, coat powders having these metals on the surface layer, and mixed powders thereof are used. The

  The conductive powder is usually contained in an amount of 40 to 97% by mass. When the content is less than 40% by mass, the conductivity of the produced conductive paste is small, and when it exceeds 97% by mass, the adhesion of the conductive paste decreases. You may mix and use the conductive polymer and metal oxide powder which form the semiconductor layer mentioned above in the electrically conductive paste.

Examples of the plating include nickel plating, copper plating, silver plating, gold plating, and aluminum plating. Examples of the deposited metal include aluminum, nickel, copper, gold, and silver.
Specifically, for example, a carbon paste and a silver paste are sequentially laminated on a conductor on which a semiconductor layer is formed and sealed with a material such as an epoxy resin to form a capacitor. The capacitor may have a lead made of a metal wire or a metal foil connected to the conductor in advance or connected later.

The capacitor of the present invention having the above-described configuration can be made into a capacitor product for various uses by using, for example, a resin mold, a resin case, a metallic outer case, a resin dipping, or an outer case using a laminate film.
Among these, a chip-shaped capacitor with a resin mold is particularly preferable because it can be reduced in size and cost.

  Specifically, in the case of the resin mold exterior, the capacitor according to the present invention includes a part of the conductor layer of the capacitor element, and a lead frame having a pair of opposed tip portions separately prepared. It is placed on the tip, and a part of the anode lead (the tip of the anode lead may be cut and used for matching the dimensions) is placed on the other tip of the lead frame. The conductive paste is solidified, and the latter is electrically and mechanically joined by welding, and then the resin is sealed by leaving a part of the tip of the lead frame, and the lead frame is cut at a predetermined portion outside the resin seal. It is manufactured by bending (when the lead frame is on the lower surface of the resin seal and is sealed leaving only the lower surface or the lower surface and side surfaces of the lead frame, it may be cut only).

  The lead frame is cut as described above and finally becomes an external terminal of the capacitor. The shape of the lead frame is foil or flat plate, and the material is iron, copper, aluminum, or these metals as a main component. An alloy is used. Part or all of the lead frame may be plated with solder, tin, titanium, gold, nickel, or the like. There may be a base plating such as nickel or copper between the lead frame and the plating.

  These various platings can also be performed on the lead frame after or before the cutting and bending process. It is also possible to perform re-plating at any time after sealing after plating before placing and connecting the capacitor element.

  The lead frame has a pair of opposed tip portions, and a gap between the tip portions insulates the anode portion and the cathode portion of each capacitor element.

  As the type of resin used for the resin mold exterior, known resins used for sealing of solid electrolytic capacitors such as epoxy resin, phenol resin, alkyd resin, etc. can be adopted, but each resin preferably uses a low stress resin. It is preferable because generation of sealing stress to the capacitor element that occurs during sealing can be reduced. Further, a transfer machine is preferably used as a manufacturing machine for sealing the resin.

The capacitor thus produced may be subjected to an aging treatment in order to repair the deterioration of the thermal and / or physical dielectric layer when the electrode layer is formed or when it is packaged.
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 by experiments because optimum values differ depending on the type, capacity, and rated voltage of the capacitor.Normally, the time is several minutes to several days, and the temperature is determined by taking into account the thermal deterioration of the voltage application jig. At 300 ° C. or lower. Aging may be performed under any conditions of reduced pressure, normal pressure, and increased pressure, and the aging atmosphere may be air, a gas such as argon, nitrogen, or helium, but is preferably water vapor. For example, when aging is performed in an atmosphere containing water vapor and then in a gas such as air, argon, nitrogen, or helium, the dielectric layer may be stabilized. It is possible to return to normal pressure and room temperature after supplying water vapor, or to leave at a high temperature of 150 to 250 ° C. for several minutes to several hours after supplying water vapor to remove excess water and perform the aging. One example of a method for supplying water vapor is a method for supplying water vapor by heat from a water reservoir placed in an aging furnace.

  As a voltage application method, it can be designed to flow an arbitrary current such as a direct current, an alternating current having an arbitrary waveform, an alternating current superimposed on the direct current, or a pulse current. It is also possible to stop the voltage application once during the aging and apply the voltage again.

  The capacitor manufactured according to the present invention has a stable capacitance because the semiconductor layer can be formed under the same stable conditions. For this reason, the capacitance distribution (variation) of the capacitor group (a large number of capacitors manufactured at the same time) is narrower than that of the conventional product. For this reason, the yield in the case of obtaining a capacitor having a specific capacitance range is improved.

  In addition, the capacitor group manufactured by the present invention can be used for digital devices such as personal computers, servers, cameras, game machines, DVDs, AV devices, mobile phones, and electronic devices such as various power sources.

  Hereinafter, specific examples of the present invention will be described in more detail, but the present invention is not limited to the following examples.

Example 1:
1. Preparation of reaction vessel for manufacturing capacitor element Gold plating is applied on a copper material having a diameter of 7 mm as shown in FIG. 3 on one side (front surface) of a copper-clad glass epoxy plate having a length of 322 mm, a width of 202 mm, and a thickness of 2 mm. A total of 640 cathode plates were prepared with 32 intervals in the length direction and 20 intervals in the width direction. Further, the other surface (back surface) was printed and wired so that the anode side of the constant current diode as shown in FIG. 2 and each cathode plate on the surface were connected in series via a through hole. The cathode portion of each constant current diode was soldered to the land of the printed wiring, and finally connected by wiring reaching the current collecting terminal. A constant current diode was selected from F-101 manufactured by Ishizuka Electronics Co., Ltd., having a density of 120 to 160 μA. The through hole was filled with epoxy resin. Next, as schematically shown in FIG. 4, a glass epoxy plate (6) having a height of 20 mm and a width of 2 mm is set up perpendicular to the surface so that each cathode plate (2) on the surface enters the room one by one. 640 small chambers (planar 8 × 8 mm) having substantially the same dimensions were produced by fastening with an adhesive resin, and holes (7) each having a diameter of 2 mm were formed at a location 5 mm from the lower center of the wall of each of the 640 chambers of the reaction vessel. . However, no hole is provided in the outermost wall. FIG. 4 (A) shows an overview of the entire reaction vessel (1), and FIG. 4 (B) schematically shows three arbitrarily connected chambers in the reaction vessel (1). The solution for forming the conductor layer was 15 mm in height, and the liquid level in each room was kept constant.

2. Production of Capacitor A tantalum sintered body having a CV of 100,000 μF · V / g (size 4.5 × 3.0 × 1.0 mm, mass 84 mg, lead wire 0.40 mmφ on the surface of 10 mm) was 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 step. The upper 2 mm of the lead wire of the conductor thus made was connected to a stainless steel plate having a length of 360 mm, a width of 20 mm, and a thickness of 2 mm by welding at 32 mm from the end with the direction aligned at 10 mm intervals. Similarly, 20 stainless steel plates to which 32 conductors were connected were prepared, and each stainless steel plate was attached to a metal frame in which 640 conductors could be arranged in the same direction with their tips aligned in parallel at intervals of 10 mm. A frame is placed on a chemical conversion tank containing a 0.1% phosphoric acid aqueous solution prepared separately, and the conductor and a part of the lead wire are immersed in the aqueous solution. The plate is used as a cathode, 10V is applied, the aqueous solution is formed at 80 ° C. for 6 hours, pulled up from the tank, washed with water and dried to form Ta ₂ O _{5 on the} inside of the pores of the conductor and on the surface of the lead wire. A dielectric layer consisting of Next, only the conductor of the frame was immersed in a 1% aqueous iron benzenesulfonate solution, pulled up, washed with water and dried seven times. A reaction vessel for producing a capacitor element was filled with a 30% ethylene glycol aqueous solution containing 3% anthraquinone-2-sulfonic acid and ethylenedioxythiophene having a saturation concentration or higher. Place the 640 conductors of the frame in the 640 chambers of the reaction vessel so that they are immersed in the chamber. Use the frame as the anode and the current collector terminal at the outer bottom of the reaction vessel as the cathode. Then, a semiconductor layer was formed. The frame was pulled up, washed with water, washed with alcohol, and dried. Then, it arrange | positioned so that a conductor and a part of lead wire might be immersed in the above-mentioned chemical conversion tank which made the chemical conversion solution 0.1% acetic acid, and re-chemical-ized at 7V, 15 minutes and 80 degreeC. The frame was pulled up, washed with water, washed with alcohol, and dried. Such semiconductor layer formation and re-chemical formation were repeated five times to obtain a final semiconductor layer. Furthermore, the electrode layer was laminated | stacked on the semiconductor layer by installing so that a conductor part might be immersed in a carbon paste tank and a silver paste tank in order, and drying.

Remove the conductors on which the electrode layers are formed from the frame, and place the conductors with the conductor wires partially cut off and placed on the anode side of both ends of the lead frame made of a copper alloy tin-plated on a separately prepared surface. The silver paste side of the conductor was placed on the cathode side, the former was connected by spot welding and the latter was connected by silver paste. Then, after sealing with an epoxy resin, the lead frame was cut and bent to produce a chip capacitor having a size of 7.3 × 4.3 × 1.8 mm. Next, aging was performed at 115 ° C. and a voltage applied to the capacitor of 3.5 V for 5 hours. The obtained capacitors have a rated 2.5 V capacity of 680 μF, the number of 525 of 720 to 645 μF, 61 of 720 to 750 μF, 49 of 645 to 610 μF, 5 of 610 to 580 μF, 5 of 580 to 550 μF, It had a capacity distribution of 0 pieces.
Further, the capacitor was manufactured for the second time in the same manner without replenishing the solution in the reaction container for manufacturing the capacitor element (liquid level adjustment). The capacitance distribution of the obtained capacitor was almost the same between the first time and the second time. The results are shown in Table 1.

Example 2:
A chip capacitor was produced in the same manner as in Example 1 except that the size of the hole in the wall was changed to 0.7 mmφ. The obtained capacitors have a rated 2.5 V capacity of 680 μF, the number of 720 to 645 μF is 556, the number of 720 to 750 μF is 28, the number of 645 to 610 μF is 56, the number of 610 to 580 μF is 0, the number of 580 to 550 μF is It had a capacity distribution of 0 pieces.
Further, the capacitor was manufactured for the second time in the same manner without replenishing the solution in the reaction container for manufacturing the capacitor element (liquid level adjustment). The capacitance distribution of the obtained capacitor was almost the same between the first time and the second time. The results are shown in Table 1.

Example 3:
A chip capacitor was manufactured in the same manner as in Example 1 except that the size of the hole in the wall was set to 0.2 mmφ. The obtained capacitors have a rated 2.5 V capacity of 680 μF, the number of 577 of 720 to 645 μF, the number of 21 of 720 to 750 μF, the number of 42 of 645 to 610 μF, the number of 0 of 610 to 580 μF, the number of 0 of 580 to 550 μF. It had a capacity distribution of 0 pieces.
Further, the capacitor was manufactured for the second time in the same manner without replenishing the solution in the reaction container for manufacturing the capacitor element (liquid level adjustment). The capacitance distribution of the obtained capacitor was almost the same between the first time and the second time. The results are shown in Table 1.

Example 4:
A chip capacitor was produced in the same manner as in Example 1 except that the size of the hole in the wall was 20 mmφ in Example 1. The obtained capacitors have a rated 2.5V capacity of 680 μF, the number of 455 of 720 to 645 μF, the number of 29 of 720 to 750 μF, the number of 108 of 645 to 610 μF, the number of 30 of 610 to 580 μF, the number of 30 of 580 to 550 μF. It had a capacity distribution of 18 pieces.
Further, the capacitor was manufactured for the second time in the same manner without replenishing the solution in the reaction container for manufacturing the capacitor element (liquid level adjustment). The capacitance distribution of the obtained capacitor was almost the same between the first time and the second time. The results are shown in Table 1.

Example 5:
1. Preparation of reaction vessel for manufacturing capacitor element In Example 1, 93 masses of silver powder was prepared from the bottom of each small chamber and the bottom of the side surface to a height of 14 mm without producing the cathode plate of each small chamber of the reaction vessel by printing technology. %, A solid paste part with a thickness of about 0.3 mm was drawn with silver paste of 7% by mass of epoxy resin, and a cathode plate was selected, and a constant current diode was selected from F-101L made by Ishizuka Electronics Co., Ltd. 60-100 μA In the same wall position as in Example 1, two slits having a length of 7 mm and a width of 1 mm were provided as holes at 5 mm and 9 mm from the bottom of each room. The solution for forming the semiconductor layer was 15 mm in height, and the liquid level in each room was constant.

2. Capacitor production Niobium primary powder (average particle size 0.32μm) ground using the hydrogen embrittlement of niobium ingots is granulated, and niobium powder with an average particle size of 110μm (because it is a fine powder, the surface is naturally oxidized and oxygen is 95,000. ppm present.). Next, it was left in a nitrogen atmosphere at 450 ° C. and then in argon at 700 ° C. to obtain a partially nitrided niobium powder (CV 298000 μF · V / g) having a nitriding amount of 9600 ppm. This niobium powder is molded with a 0.37mmφ niobium wire and then sintered at 1280 ° C to obtain a size of 4.0 x 3.5 x 1.7mm (mass 0.08g. The niobium wire becomes the lead wire, 3.7mm inside the sintered body, external A plurality of sintered bodies (conductors) having a thickness of 10 mm were prepared. Next, the same number of conductors were connected to the same stainless steel plate as in Example 1, and then the same number of conductors were disposed on the metal frame. A dielectric layer containing Nb ₂ O ₅ as a main component was formed on the surface of the conductor and part of the lead wire by forming only the voltage at 20V.

Next, after placing the reactor for producing the capacitor element in a low-temperature chamber controlled at 12 ° C., the anthraquinone-2-sulfonic acid of Example 1 was replaced with pyrrole, and the energization voltage and re-forming voltage were set to 23 V and 14 V, respectively. Further, a semiconductor layer and an electrode layer were formed and sealed in the same manner as in Example 1 except that the energization time was 90 minutes and the number of reactions was 11, and a chip-like solid having a size of 7.3 × 4.3 × 2.8 mm was formed. An electrolytic capacitor was produced. The obtained capacitor has a rated 4V capacity of 1000 μF, and has a capacity distribution of 526 of 950 to 1050 μF, 16 of 1050 to 1100 μF, 81 of 950 to 900 μF, and 17 of 900 to 850 μF. It was.
Further, the capacitor was manufactured for the second time in the same manner without replenishing the solution in the reaction container for manufacturing the capacitor element (liquid level adjustment). The capacitance distribution of the obtained capacitor was almost the same between the first time and the second time. The results are shown in Table 2.

Comparative Example 1:
1. Preparation of reaction vessel for manufacturing capacitor element Gold plating is applied on a copper material having a diameter of 7 mm as shown in FIG. 3 on one side (front surface) of a copper-clad glass epoxy plate having a length of 322 mm, a width of 202 mm, and a thickness of 2 mm. A total of 640 cathode plates were prepared with 32 intervals in the length direction and 20 intervals in the width direction. Furthermore, the other surface (back surface) was printed and wired so that the anode side of the constant current diode as shown in FIG. 2 and each cathode plate on the surface were connected in series via a through hole. The cathode portion of each constant current diode was soldered to the land of the printed wiring, and finally connected by wiring reaching the current collecting terminal. A constant current diode was selected from F-101 manufactured by Ishizuka Electronics Co., Ltd., having a density of 120 to 160 μA. The through hole was filled with epoxy resin. Next, a glass epoxy plate with a height of 20 mm and a width of 2 mm is vertically placed on the surface so that each cathode plate on the surface enters into the room, and is fastened with an adhesive resin. 640 were produced, and a reaction vessel for producing a capacitor element was produced in which the cross section of each room was as shown in FIG.

2. Production of Capacitor A CV 100,000 μF · V / g tantalum sintered body (size 4.5 × 3.0 × 1.0 mm, mass 84 mg, lead wire 0.40 mmφ is exposed on the surface of 7 mm) was 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 step. The top 2 mm of the conductor lead wire thus made was connected to a stainless steel plate having a length of 360 mm, a width of 20 mm, and a thickness of 2 mm by welding 32 pieces with the direction aligned at intervals of 10 mm from a position 25 mm from the end. Similarly, 20 stainless steel plates to which 32 conductors were connected were prepared, and each stainless steel plate was attached to a metal frame in which 640 conductors could be arranged in the same direction with their tips aligned in parallel at intervals of 10 mm. A frame is placed on a chemical conversion tank containing a 0.1% phosphoric acid aqueous solution prepared separately, and the conductor and a part of the lead wire are immersed in the aqueous solution. The plate is used as a cathode, 10V is applied, the aqueous solution is formed at 80 ° C. for 6 hours, pulled up from the tank, washed with water and dried to form Ta ₂ O _{5 on the} inside of the pores of the conductor and on the surface of the lead wire. A dielectric layer consisting of Next, the frame conductor alone was dipped in a 10% ethylbenzene-2-sulfonic acid aqueous solution, pulled up, washed with water and dried seven times, and then 3% anthraquinone-2-sulfonic acid and ethylene at a saturated concentration or higher. Arranged so that 640 conductors of the frame are immersed in 640 chambers of a reaction vessel for manufacturing a capacitor element in which 30% ethylene glycol aqueous solution containing dioxythiophene is distributed at the same height in each chamber, Using the frame as the anode and the current collecting terminal at the outer bottom of the reaction vessel as the cathode, current was passed at 13.5 V for 1 hour at room temperature to form a semiconductor layer. After raising the frame, washing with water, washing with alcohol, and drying, place the conductor and the lead wire in the above-mentioned chemical conversion bath with 0.1% acetic acid so that the conductor and part of the lead wire are immersed in 7V, 15 minutes, 80 ° C. Re-formed in The frame was pulled up, washed with water, washed with alcohol, and dried. Such semiconductor layer formation and re-chemical formation were repeated five times to obtain a final semiconductor layer. Furthermore, the electrode layer was laminated | stacked on the semiconductor layer by installing so that a conductor part might be immersed in a carbon paste tank and a silver paste tank in order, and drying.

Remove the conductors on which the electrode layers are formed from the frame, and place the conductors with the conductor wires partially cut off and placed on the anode side of both ends of the lead frame made of a copper alloy tin-plated on a separately prepared surface. The silver paste side of the conductor was placed on the cathode side, the former was connected by spot welding and the latter was connected by silver paste. Then, after sealing with an epoxy resin, the lead frame was cut and bent to produce a chip capacitor having a size of 7.3 × 4.3 × 1.8 mm. Next, aging was performed at 115 ° C. and a voltage applied to the capacitor of 3.5 V for 5 hours. The appearance capacity distribution of the obtained capacitor was within a range of ± 10% of the average capacity. Specifically, the obtained capacitors had a rated 2.5 V capacity of 680 μF, and had a capacitance distribution of 594 from 720 to 645 μF, 17 from 720 to 750 μF, and 29 from 645 to 610 μF.
Further, the capacitor was manufactured for the second time in the same manner without replenishing the solution in the reaction container for manufacturing the capacitor element (liquid level adjustment). The capacity distribution of the obtained capacitors was widened, and the appearance capacity distribution appeared to exceed ± 20% of the set capacity (first average capacity).
The number of capacitors obtained is 565 of 720 to 645 μF, 18 of 720 to 750 μF, 38 of 645 to 610 μF, 11 of 610 to 575 μF, 2 of 575 to 540 μF, and 540 to 510 μF. It had 5 capacity distributions. The results are shown in Table 3.
From each Example and Comparative Example 1, it can be seen that the capacitance distribution of the capacitor group obtained in each Example is clearly more stable than the capacitor group obtained in Comparative Example 1.

Comparative Example 2:
In Example 1, the reaction vessel for manufacturing the capacitor element of the present invention was not used, but a conventional reaction vessel, that is, the same size, but each room had individual cathode plates and a current sink type current source. In the reaction vessel provided with a cathode plate plated with gold on copper having the same size as the bottom area inside the lower surface of the vessel, except that the semiconductor layer was formed by energizing the cathode plate as a cathode. In the same manner as in Example 1, a chip capacitor was produced. The appearance capacity distribution of the obtained capacitor was more than ± 20% of the average capacity. Specifically, the obtained capacitors have a rated 2.5 V capacity of 680 μF, the number of 359 of 720 to 645 μF, the number of 15 of 720 to 750 μF, the number of 2 of 750 to 780 μF, the number of 150 of 645 to 610 μF. , 610-575 μF number 93, 575-540 μF number 17, 540-510 μF number 4 capacitance distribution. The results are shown in Table 3.
From each Example and Comparative Example 2, it can be seen that the capacitance distribution of the capacitor group obtained in each Example is clearly narrower than that of the capacitor group obtained in Comparative Example 2.

  The present invention provides a reaction container for manufacturing a capacitor element that forms a semiconductor layer by energization through a current sink type constant current source and a method for manufacturing the capacitor element. It is possible to obtain a capacitor group having a narrow distribution and a capacitance distribution in which the appearance capacitance is in the range of the average capacitance ± 20%.

The schematic cross section which shows the structure of 1 form of the reaction container for capacitor element manufacture of this invention. The schematic diagram which shows the structure of the container bottom part inner surface (surface) of 1 form of the reaction container for capacitor element manufacture of this invention. The schematic diagram which shows the structure of the container bottom part back surface of 1 form of the reaction container for capacitor element manufacture of this invention. (A) The schematic diagram which shows the general view of the whole reaction container for capacitor element manufacture in Example 1, (B) The expansion schematic diagram of 3 rooms of a part in FIG. 4 (A).

Explanation of symbols

1 Reaction vessel 2 Cathode plate 3 Constant current diode 4 Current collector terminal 5 Conductor 6 Frame (wall)
7 holes 8 rooms

Claims (12)

  A reaction vessel for forming a semiconductor layer by an energization method by simultaneously immersing a plurality of conductors having a dielectric layer formed on the surface thereof in an electrolytic solution in a reaction vessel, wherein each conductor is formed in the reaction vessel. A corresponding plurality of cathodes and chambers are provided, each cathode being electrically connected to an individual constant current source, and each chamber having at least one electrolyte moveable between the other chambers A reaction vessel for producing a capacitor element, characterized in that a passage is provided.   The reaction vessel for manufacturing a capacitor element according to claim 1, wherein the passage is a hole opened in the wall surface of the room, and the size (diameter) thereof is 0.1 to 10 mm.   The reaction container for manufacturing a capacitor element according to claim 1 or 2, wherein the passage is opened in a slit shape on the wall surface of the room, and the gap between the slits is 0.1 to 10 mm.   The reaction container for manufacturing a capacitor element according to claim 1, wherein a cathode is provided on a bottom surface of each room.   The reaction container for manufacturing a capacitor element according to any one of claims 1 to 4, wherein a cathode is provided on a wall surface of each room.   The reaction container for manufacturing a capacitor element according to claim 1, wherein the plurality of constant current sources are composed of a plurality of constant current diodes, each cathode is electrically connected, and each anode is connected to the cathode.   7. Each cathode is arrange | positioned inside the bottom part of reaction container, each constant current diode is arrange | positioned outside the reaction container, and the cathodes of each constant current diode are electrically connected, and it collects in a terminal. Reaction vessel for manufacturing capacitor elements.   The bottom of the reaction vessel for capacitor element production is made of an insulating substrate, each cathode is provided on the inner surface of the reaction vessel of the insulating substrate, and a constant current source corresponding to each cathode is provided on the outer surface thereof, Both are electrically connected. The reaction container for capacitor element manufacture in any one of Claims 1-7.   The reaction vessel for manufacturing a capacitor element according to claim 1, wherein the cathode is a film metal material.   A method for producing a capacitor element, comprising using the reaction container for producing a capacitor element according to claim 1.   A plurality of conductors having a dielectric layer are immersed in the electrolytic solution in a reaction vessel for manufacturing a capacitor element filled with the electrolytic solution, and each cathode provided in the reaction vessel with the conductive material side as an anode serves as a cathode. When the step of forming the semiconductor layer on the dielectric layer by a current application method is performed a plurality of times, the step is repeatedly performed without adjusting the liquid level of each chamber of the reaction container for manufacturing the capacitor element. Manufacturing method of capacitor element.   The manufacturing method of the capacitor | condenser which seals the capacitor | condenser element obtained by the method of Claim 10 or 11.

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