JPH08130166A - Method for manufacturing solid electrolytic capacitor - Google Patents

Abstract

(57) [Summary] [Structure] A solid electrolyte and a cathode layer are sequentially formed on the valve action metal surface on which a dielectric oxide film is formed, leaving a part to be an anode extraction part, and an anode extraction part and an anode lead are formed. In the method of manufacturing a solid electrolytic capacitor in which a frame and a cathode layer and a cathode lead frame are respectively joined, the surface of the cathode layer and the cathode lead frame are joined by a metal wire using a wire bonder, or the cathode layer After joining the metal foil piece to at least a part of the surface, the surface of the metal foil piece and the cathode lead frame are joined with a metal wire using a wire bonder. is there. [Effect] A small-sized and large-capacity solid electrolytic capacitor can be easily manufactured without impairing the capacitor characteristics. Also,
Since the cathode layer and the cathode lead frame can be joined with a metal wire using a wire bonder, mass productivity is excellent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid electrolytic capacitor.

[0002]

2. Description of the Related Art There has been proposed a solid electrolytic capacitor having a structure in which a dielectric oxide film is formed on the surface of a valve metal and a conductive polymer film is formed on the dielectric oxide film to form a solid electrolyte.

In Japanese Unexamined Patent Publication (Kokai) No. 5-159983, a dielectric oxide film is formed on the surface of a valve metal, and a large number of grid patterns are formed by using an insulating resin, and a conductive pattern is formed in the grid. A method for producing a solid electrolytic capacitor is disclosed, in which a solid electrolyte made of a polymer is formed, a cathode layer made of a carbon layer and a silver layer is further formed, and then a foil is cut to obtain an element. This method can produce a small-sized and large-capacity solid electrolytic capacitor by a combination of simple steps and is excellent in mass productivity. However, the cathode layer and the cathode lead frame must be electrically connected to the cathode layer after insulating the cut surface of the foil and bonded to the cathode lead frame with silver paste, which is a complicated process and is obtained. There is a problem such as a large equivalent series resistance of the solid electrolytic capacitor.

Further, Japanese Unexamined Patent Publication (Kokai) No. 5-159982 discloses a method of manufacturing a solid electrolytic capacitor using a metal wire such as gold, nickel or platinum for joining a cathode layer and a cathode lead frame. This method can obtain excellent capacitor characteristics such as small equivalent series resistance of the obtained solid electrolytic capacitor, but metal wires must be joined one by one with conductive paste or solder, which is problematic in terms of mass productivity. There is.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a small-sized and large-capacity solid electrolytic capacitor which does not impair the capacitor characteristics. Further, the solid electrolytic capacitor can be manufactured in a simple process with good mass productivity. A method of manufacturing a capacitor is provided.

[0006]

As a result of intensive studies, the present inventors have completed a method of manufacturing a solid electrolytic capacitor capable of solving the above problems.

That is, according to the present invention, the solid electrolyte and the cathode layer are sequentially formed on the surface of the valve action metal on which the dielectric oxide film is formed, which is to be the anode lead portion, and the anode lead portion and the anode lead are formed. In a method for manufacturing a solid electrolytic capacitor, which joins a frame and a cathode layer to a cathode lead frame, the surface of the cathode layer and the cathode lead frame are joined together with a metal wire using a wire bonder. A method for manufacturing a capacitor, in which a solid electrolyte and a cathode layer are sequentially formed on the surface of a valve action metal on which a dielectric oxide film has been formed, which is to be an anode lead portion, and an anode lead portion and an anode lead are formed. In a method for manufacturing a solid electrolytic capacitor in which a frame and a cathode layer are joined to a cathode lead frame, a metal foil piece is provided on at least a part of the surface of the cathode layer. After bonding, the surface and the cathode lead frame of the metal foil piece, a manufacturing method of a solid electrolytic capacitor characterized in that it is joined by a metal wire using a wire bonder.

The method for manufacturing the solid electrolytic capacitor of the present invention will be described below with reference to the drawings.

The valve metal used in the present invention is aluminum, tantalum, titanium or an alloy thereof, and is in the form of foil or plate. Aluminum foil is used as the valve metal and a conductive polymer film is used as the solid electrolyte. The case of using will be described.

After etching the surface of the large area aluminum foil 1, anodization is performed in an aqueous solution of ammonium adipate or the like to form a dielectric oxide film 2.

As shown in FIG. 1, the anode lead-out portion 3 and the solid electrolyte forming portion 4 (first pattern) are left on both surfaces of the aluminum foil 1 on which the dielectric oxide film 2 is formed.
The first insulating coating film 5 is formed. Next, the second insulating coating film 6 is formed, leaving a pattern (second pattern) which is larger than the first insulating coating film 5 in part. Further, a conductive coating film 7 which becomes a power feeding electrode during electrolytic polymerization is formed on the second insulating coating film 6. At this time, the conductive coating film 7 is formed so as not to come into contact with the solid electrolyte forming portion 4 exposed in the second pattern.

Next, as shown in FIG. 2, a part 8 of the first insulating coating film and a part 9 of the conductive coating film formed on the second insulating coating film are left, and the third The insulating coating film 10 is formed and the conductive coating film 7 is masked. At this time, the end portion of the conductive coating film is not masked. FIG. 3 is a sectional view taken along the line ab of FIG.

The insulating coating film used in the present invention is made of silicone resin, fluorine resin, epoxy resin, phenol resin,
It is a heat-resistant polymer material such as a polyimide resin, a polyester resin, a polyphenylene sulfide resin, or a mixture or copolymer thereof.

The conductive coating film used in the present invention is
Conductive materials such as silver paste, carbon paste, nickel paste, and copper paste.

In order to form the insulating coating film and the conductive coating film, a printing method such as a roll coater, a reverse coater or screen printing is preferable in terms of mass productivity.

A foil similar to that shown in FIG. 1 can be obtained even if a pattern is formed in advance on an aluminum foil having a large area with an insulating coating film, followed by etching and chemical conversion.

Then, a conductive precoat layer 11 is formed on the solid electrolyte forming portion 4, the first insulating coating portion 8 and the conductive coating portion 9 which are exposed in the second pattern. To form. At this time, the conductive precoat layer is not formed on the anode lead-out portion 3 exposed in the first pattern.

The conductive precoat layer is formed by a method of forming a conductive polymer film by chemical oxidative polymerization of a conductive polymer monomer, or by forming a thin film of a conductive metal oxide such as conductive manganese dioxide by thermal decomposition of manganese salt. Or a method in which a solvent-soluble conductive polymer such as polyaniline or a tetracyanoquinodimethane complex solution is impregnated and dried to form a conductive film.

As an example of forming the conductive precoat layer,
Exposed solid electrolyte forming portion 4 in the second pattern, part 8 of the first insulating coating film and part 9 of the conductive coating film.
After a certain amount of an organic solvent solution of a pyrrole monomer was dropped onto the above, a certain amount of an aqueous solution of an oxidant was then added dropwise at room temperature.
A method of forming a conductive polypyrrole film by leaving it for 30 minutes, followed by washing and drying.

Then, the damaged portion of the dielectric oxide film formed up to the formation of the conductive precoat layer is chemically repaired. The chemical conversion restoration is performed by immersing the aluminum foil in an aqueous solution of ammonium adipate or the like and performing anodization.

Thereafter, as shown in FIG. 4, a conductive polypyrrole film 12 is formed on the conductive precoat layer 11 by electrolytic polymerization. Conductive polypyrrole film 12 by electrolytic polymerization,
A part of the end of the conductive coating film 7 is used as an anode and the supporting electrolyte is 0.01 to
It is formed by carrying out electrolytic polymerization in an electrolytic solution containing 2 mol / l and 0.01 to 5 mol / l of pyrrole monomer.

As the anion of the supporting electrolyte used in the electropolymerization of the present invention, hexafluoroline, hexafluoroarsenic, hexafluoroantimony, tetrafluoroboron,
Halide ions such as perchloric acid, halogen ions such as iodine, bromine and chlorine, alkylsulfonic acid ions such as methanesulfonic acid and dodecylsulfonic acid, benzenesulfonic acid, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, benzenedisulfonic acid Alkyl-substituted or unsubstituted benzene mono- or disulfonate ion, such as
Alkyl-substituted or non-substituted ion of naphthalene sulfonic acid having 1 to 4 sulfonic acid groups such as 2-naphthalene sulfonic acid and 1,7-naphthalenedisulfonic acid, alkyl-substituted or non-substituted alkyl biphenyl sulfonic acid, biphenyl disulfonic acid, etc. substituted biphenyl sulfonate ion, polystyrenesulfonic acid, naphthalenesulfonic acid formalin condensates, etc. of the polymer sulfonate ion, bis salicylate boron, bis catecholate boric arsenide boron compound ions, heteropoly acids such as PMo ₁₂ O _{4 0} It is an ion, preferably a sulfonate ion. The cation is an alkali metal ion such as lithium, potassium or sodium, or a quaternary ammonium ion such as ammonium or tetraalkylammonium. The compounds include LiPF ₆ , LiAsF ₆ , LiBF ₄ , KI and NaP.
F ₆ , NaClO ₄ , sodium toluenesulfonate, tetrabutylammonium toluenesulfonate, sodium 1,7-naphthalenedisulfonate, tetraethylammonium n-octadecylnaphthalenesulfonate, tetramethylammonium bissalicylate and the like can be mentioned.

Then, a cathode layer 13 is formed on the surface of the conductive polypyrrole film 12 by electrolytic polymerization using a carbon paste and a silver paste. The back side is processed similarly.

Next, mechanical means such as a cutter or YAG
Using a thermal means such as a laser, leaving the portion where the anode extraction portion 3 and the solid electrolyte are formed, the first insulating coating film and the second insulating coating film are cut at the positions shown in FIG. Get the element.

Next, the obtained device and anode lead frame
14 and the cathode lead frame 15 are joined together.

The anode lead-out portion 3 and the anode lead frame 14 of the obtained element are joined by welding such as ultrasonic welding, spot welding, laser welding, or soldering.

Next, the back surface of the cathode layer 13 and the cathode lead frame 15 are joined with silver paste 16 or the like. Then, using a wire bonder, the surface of the cathode layer 13 and the cathode lead frame 15 are joined with a metal wire 17.

The wire bonder used in the present invention is a device for bonding a metal wire to the surface of a metal by an ultrasonic thermocompression bonding method or an ultrasonic pressure bonding method, and is usually used for drawing out electrodes in the production of integrated circuit parts and the like. Has been.

By using the wire bonder, the surface of the cathode layer 13 and the cathode lead frame 15 can be joined without the metal wire 17 coming into contact with the cut surface of the aluminum foil, and there is no adverse effect on the capacitor characteristics. It has excellent mass productivity.

Examples of the metal wire 17 used in the present invention include a gold wire and an aluminum wire. The aluminum wire can be joined without applying heat, and is suitable for joining the surfaces of the conductive polymer membranes that do not like high heat. is there. Further, the diameter of the metal wire is preferably 10 to 400 μm. If the diameter of the metal wire exceeds 400 μm, it will be difficult to bond with a wire bonder, and if it is less than 10 μm, the strength will be insufficient. The number of metal wires used for bonding is usually one, but a plurality of metal wires may be used to reduce the electric resistance.

Further, as shown in FIG. 6, after the metal foil piece 18 is joined to the surface of the cathode layer 13 with silver paste 16 or the like, the surface of the metal foil piece 18 and the cathode lead frame 15 are bonded using a wire bonder. And may be joined with the metal wire 17. By using this method, it is possible to easily and surely join and the equivalent series resistance can be further reduced.

As the metal foil piece 18 used in the present invention,
Examples include foil pieces of aluminum, stainless steel, nickel, gold, copper, etc., and alloy foil pieces of 42 alloy, nickel silver, etc. Nickel white is preferable in terms of electrical conductivity and price.

The ratio of the area of the metal foil piece 18 to the surface area of the cathode layer (hereinafter abbreviated as area ratio) is preferably 1 to 70%. If the area ratio is less than 1%, it is difficult to weld the metal wire, and if it is more than 70%, the equivalent series resistance becomes large.

[0034]

The present invention will be described below with reference to examples. The present invention is not limited to the examples.

Example 1 After etching the surface of an aluminum foil (length 30 mm × width 50 mm), it was subjected to chemical conversion treatment in an aqueous solution of ammonium adipate at a voltage of 40 V to form a dielectric oxide film, and then as shown in FIG. And leaving a grid pattern (2 rows long × 8 rows wide, first pattern) of the anode extraction portion 3 (length 3 mm × width 1 mm) and the solid electrolyte formation portion 4 (length 3 mm × width 5 mm).
After screen-printing the epoxy resin, heat cure and
The first insulating coating film 5 was formed.

Subsequently, an epoxy resin is screen-printed, leaving a pattern (second pattern), a part of which is larger than the first insulating coating film 5, and then heat-cured to form a second insulating coating film. 6 was formed. Further, the fish paste-like conductive coating film 7 was formed on the second insulating coating film 6 with nickel paste.

Then, as shown in FIG. 2, a part of the first insulating coating film 8 and a part of the conductive coating film 9 are left, screen printing of an epoxy resin is performed, and then heat curing is carried out. The insulating coating film 10 was formed and the conductive coating film 7 was masked. The back side was treated similarly.

Then, in the second pattern, an 8-channel multichannel micropipette (SOCORE
(Manufactured by Company X), 5 ml of an ethanol solution containing 30 wt% of pyrrole monomer is added dropwise, and after leaving it for 1 minute, ammonium persulfate is added.
10 ml of a 0.1 mol / l aqueous solution was added dropwise. After standing for 5 minutes, it was washed with water and dried to form a polypyrrole film 11 by chemical polymerization. The back side was treated similarly.

Further, anodization was carried out in an aqueous solution of ammonium adipate at a voltage of 40 V to recover the chemical conversion.

Next, pyrrole monomer 0.4 mol / l, 1,7
-Tetraethylammonium naphthalene disulfonate 0.4
It was immersed in a stainless steel container containing an electrolytic solution of mol / l and acetonitrile, part of the end of the conductive coating film 7 was connected to a power source to serve as an anode, and the stainless steel container was used as a cathode. mA / pin, 90 minutes) to form a polypyrrole film 12 by electrolytic polymerization. After coating a carbon paste and a silver paste on the polypyrrole film by electrolytic polymerization to form the cathode layer 13, using a YAG laser,
16 elements were obtained by cutting at the cutting points shown in FIG.

As shown in FIG. 5, by spot welding,
Anode lead part 3 and anode lead frame of the obtained device
Joined 14 and. In addition, after bonding the back surface of the cathode layer 13 and the cathode lead frame 15 with a silver paste 16, using a wire bonder (SW-1-20 type manufactured by Ultrasonic Industries Co., Ltd.), the surface of the cathode layer 13 The cathode lead frame 15 was joined with an aluminum wire 17 (diameter 50 μm).

Next, eight solid electrolytic capacitors having a rated voltage of 16 V and a rated electrostatic capacity of 10 μF were completed by molding with epoxy resin.

The average value of the initial characteristics of the obtained solid electrolytic capacitor is as follows: electrostatic capacity at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.68%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 42mΩ, voltage 16V
The leakage current was 0.01 μA or less.

Example 2 Eight solid electrolytic capacitors were completed in the same manner as in Example 1 except that an aluminum wire (diameter: 10 μm) was used instead of the aluminum wire 17 (diameter: 50 μm).

The average values of the initial characteristics of the obtained solid electrolytic capacitor are as follows: capacitance at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.69%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 49mΩ, voltage 16V
The leakage current was 0.01 μA or less.

Example 3 Eight solid electrolytic capacitors were completed in the same manner as in Example 1 except that aluminum wire 17 (diameter 50 μm) was used instead of aluminum wire 17 (diameter 50 μm).

The average value of the initial characteristics of the obtained solid electrolytic capacitor is as follows: electrostatic capacity at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.66%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 39mΩ, voltage is 16V
The leakage current was 0.01 μA or less.

Example 4 Eight solid electrolytic capacitors were completed in the same manner as in Example 1 except that aluminum wire (diameter: 380 μm) was used instead of aluminum wire 17 (diameter: 50 μm).

The average values of the initial characteristics of the obtained solid electrolytic capacitor are as follows: capacitance at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.65%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 35mΩ, voltage is 16V
The leakage current was 0.01 μA or less.

Example 5 In Example 1, as shown in FIG. 6, the anode lead portion 3 of the obtained device and the anode lead frame 14 were joined by ultrasonic welding, and the cathode of the obtained device was joined. Layer 13 surface (length 3 mm x width 5 mm, area 15 mm ² ) and nickel silver 18 (length 2 mm x)
3 mm in width, 40% in area ratio) are bonded with silver paste 16, and the back surface of cathode layer 13 and cathode lead frame 15 are bonded with silver paste 16, and then wire bonder (SW manufactured by Ultrasonic Industry Co., Ltd.)
-1-20 type), using nickel silver 18 and cathode lead frame
Eight solid electrolytic capacitors having a rated voltage of 16 V and a rated electrostatic capacity of 10 μF were completed in the same manner as in Example 1 except that 15 and 15 were joined by an aluminum wire 17 (diameter 50 μm).

The average value of the initial characteristics of the obtained solid electrolytic capacitor is as follows: electrostatic capacity at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.60%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 32mΩ, voltage is 16V
The leakage current was 0.01 μA or less.

Example 6 Eight solid electrolytic capacitors were completed in the same manner as in Example 1, except that aluminum wire (diameter: 10 μm) was used instead of aluminum wire 17 (diameter: 50 μm).

The average value of the initial characteristics of the obtained solid electrolytic capacitor is as follows: capacitance at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.61%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 40mΩ, voltage is 16V
The leakage current was 0.01 μA or less.

Example 7 Eight solid electrolytic capacitors were completed in the same manner as in Example 1 except that aluminum wire (diameter 100 μm) was used instead of aluminum wire 17 (diameter 50 μm).

The average value of the initial characteristics of the obtained solid electrolytic capacitor is as follows: capacitance at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.63%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 28mΩ, voltage 16V
The leakage current was 0.01 μA or less.

Example 8 Eight solid electrolytic capacitors were completed in the same manner as in Example 1 except that aluminum wire (diameter: 380 μm) was used instead of aluminum wire 17 (diameter: 50 μm).

The average value of the initial characteristics of the obtained solid electrolytic capacitor is as follows: electrostatic capacity at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 0.59%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 24mΩ, voltage 16V
The leakage current was 0.01 μA or less.

Comparative Example In Example 5, nickel silver 18 (length 2 mm × width 3 mm, area ratio 40)
% Instead of nickel silver 18 (3 mm length x 4 mm width, area ratio 80
%), And eight solid electrolytic capacitors were completed in the same manner as in Example 2.

The average value of the initial characteristics of the obtained solid electrolytic capacitor is as follows: capacitance at frequency 120 Hz, 10.5 μF, tangent of loss angle (tan δ) at frequency 120 Hz, 1.68%, frequency 1
Equivalent series resistance (ESR) at 00kHz is 720mΩ, voltage 16V
The leakage current was 0.01 μA or less.

[0060]

According to the method of the present invention, a small-sized and large-capacity solid electrolytic capacitor can be easily manufactured without impairing the capacitor characteristics. Further, since the cathode layer and the cathode lead frame can be joined with a metal wire using a wire bonder, mass productivity is excellent.

[Brief description of drawings]

FIG. 1 is a plan view in which a pattern is formed on an aluminum foil with an insulating coating film.

FIG. 2 is a plan view showing a cut portion.

FIG. 3 is a sectional view taken along line ab of FIG.

FIG. 4 is a cross-sectional view showing a location where a conductive precoat layer is formed.

FIG. 5 is a schematic cross-sectional view in which an element is connected to a lead frame.

FIG. 6 is a schematic cross-sectional view in which a metal foil piece is joined to the surface of the cathode layer and the device is connected to a lead frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum foil 2 Dielectric oxide film 3 Anode extraction part exposed by the first pattern 4 Solid electrolyte formation part exposed by the first pattern 5 First insulating coating film 6 Second insulating coating film 7 Conductivity Coating 8 Part of conductive coating 9 Part of first insulating coating 10 Third insulating coating 11 Conductive precoat layer 12 Conductive polypyrrole film by electrolytic polymerization 13 Cathode layer 14 Cathode lead frame 15 Anode lead frame 16 Silver paste 17 Metal wire 18 Metal foil piece

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[Procedure amendment]

[Submission date] June 9, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of Codes] 1 Aluminum foil 2 Dielectric oxide film 3 Anode lead-out portion exposed in the first pattern 4 Solid electrolyte forming portion exposed in the first pattern 5 First insulating coating film 6 Second insulation Conductive coating 7 Conductive coating 8 Part of first insulating coating 9 Part of conductive coating 10 Third insulating coating 11 Conductive precoat layer 12 Conductive polypyrrole film by electrolytic polymerization 13 Cathode Layer 14 Anode lead frame 15 Cathode lead frame 16 Silver paste 17 Metal wire 18 Metal foil piece

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Hideo Yamamoto Inventor Hideo Yamada 2470 Handa Shibukawa City Gunma Japan Carlite Co., Ltd. Research and Development Center

Claims (4)

[Claims] 1. A solid electrolyte and a cathode layer are sequentially formed on a surface of a valve action metal on which a dielectric oxide film is formed, which is to be an anode lead portion, and an anode lead portion, an anode lead frame and a cathode layer. In the method for manufacturing a solid electrolytic capacitor in which a cathode lead frame and a cathode lead frame are bonded to each other, the surface of the cathode layer and the cathode lead frame are bonded with a metal wire using a wire bonder. . 2. A solid electrolyte and a cathode layer are sequentially formed on the surface of the valve action metal on which the dielectric oxide film has been formed, which will be an anode lead portion, and the anode lead portion, the anode lead frame and the cathode layer. In the method for producing a solid electrolytic capacitor for joining a cathode lead frame and a cathode lead frame, after joining a metal foil piece to at least a part of the surface of the cathode layer, the surface of the metal foil piece and the cathode lead frame form a wire bonder. A method for manufacturing a solid electrolytic capacitor, which is characterized by being joined with a metal wire. 3. The method for producing a solid electrolytic capacitor according to claim 1, wherein the metal wire is aluminum having a diameter of 10 to 400 μm. 4. The metal foil piece has a surface area of the cathode layer ranging from 1 to 1.
3. White nickel having an area of 70%.
A method for manufacturing a solid electrolytic capacitor as described in.