TW201334001A - Method of manufacturing solid electrolytic capacitor, and solid electrolytic capacitor - Google Patents

Abstract

Provided are a solid electrolytic capacitor manufacturing method and solid electrolytic capacitor with which it is possible to more reliably and simply achieve insulation between a capacitor element and a terminal plate with a sealing resin. A capacitor element is formed having a negative electrode part in which a portion of the surface area of a valve metal is enlarged and a dielectric oxide film layer, a solid electrolyte layer, and an electrode extraction part are formed, and a positive electrode part in which an electrode extraction part is formed in a portion of the valve metal. A positive electrode electrode plate and a negative electrode electrode plate are positioned in the same plane with a gap maintained therebetween, with an insulating resin interposed in the gap, forming a terminal plate. Prior to bringing the capacitor element and the terminal plate together, an uncured sealing resin is positioned upon the positive electrode electrode plate of the terminal plate, and a conductive bonding agent is positioned in the negative electrode electrode plate of the terminal plate. The capacitor element and the terminal plate are brought together while being compressed, the electrode extraction parts are brought into contact with the positive electrode electrode plate of the terminal plate, and the sealing resin and the conductive bonding agent are cured.

Description

Method for manufacturing solid electrolytic capacitor and solid electrolytic capacitor

The present invention relates to a solid electrolytic capacitor assembled by overlapping a terminal plate and a capacitor element in a corresponding surface.

The capacitor is a passive element and has an electrostatic capacitance, and performs electric storage and discharge of electric charges corresponding to the electrostatic capacitance. The solid electrolytic capacitor is a capacitor in which a valve-acting metal such as aluminum is used as an electrode, the electrode is chemically treated to form a dielectric layer, and a conductive polymer is used as a solid electrolyte layer.

With the recent high frequency of electronic devices, capacitors are excellent in transient responsiveness so that charges can be supplied at a speed faster than conventionally, and products having higher impedance characteristics in a high frequency region than conventional ones are also known. This is to stabilize the power supply voltage of a digital circuit that operates at a high frequency and requires a large current.

In view of this requirement, in solid electrolytic capacitors, there is a strong demand for low ESR (equivalent series resistance) for high frequency, and low ESL (equivalent series) with excellent noise removal or transient responsiveness. Inductance). In the solid electrolytic capacitor, in order to achieve low ESL, a method of shortening the current path length as much as possible or a method of canceling the magnetic field formed by the current path by the magnetic field formed by the other current path has been proposed.

For example, the applicant proposes a capacitor in Japanese Patent Laid-Open Publication No. 2010-239091 or International Publication No. WO/2011/02155. A novel solid electrolytic capacitor in which a component is combined with a substrate. In the solid electrolytic capacitor of Japanese Laid-Open Patent Publication No. 2010-239091, the capacitor element is formed with a dielectric oxide film layer on the inner surface of the concave portion provided in the center of the anode body, and passes through the solid electrolyte layer and the cathode portion to be external to the capacitor element. Forming an outlet for electricity.

Further, in the capacitor element, the cathode electrode is taken out from the outside of the solid electrolytic capacitor through the mounting substrate, and the anode portion is taken out through the anode portion and the conductor on which the substrate is mounted, as the anode portion is formed around the central portion of the capacitor element. According to such a solid electrolytic capacitor, it is possible to shorten the current path of both the anode and the cathode inside the solid electrolytic capacitor.

In the solid electrolytic capacitor of the international publication WO/2011/02155, the substrate to be combined with the capacitor element includes the following terminal plates. That is, the terminal plate is disposed on the same plane as the anode electrode plate and the cathode electrode plate formed of the thin metal plate. The insulating resin is interposed between the anode electrode plate and the cathode electrode plate, and the anode electrode plate and the cathode electrode plate are electrically insulated by an insulating resin, and the two electrode portions are integrated into a sheet shape.

Such a terminal plate is superposed on the connection surface of the capacitor element, and the anode electrode plate of the terminal plate is electrically connected to the anode lead portion of the capacitor element, and the cathode electrode of the terminal plate is electrically connected to the cathode lead portion of the capacitor element. According to such a technique, the distance from the anode lead portion and the cathode lead portion of the capacitor element to the current outlet, that is, the distance from the anode electrode plate and the cathode electrode plate of the terminal plate can be achieved only to the distance of the terminal plate thickness. However, it is possible to shorten the current path.

In the technique disclosed in Japanese Laid-Open Patent Publication No. 2010-239091 or the International Publication No. WO/2011/02155, the distance from the capacitance forming portion of the solid electrolytic capacitor to the electrode serving as the power outlet is extremely short. It can promote the thinning of the solid electrolytic capacitor. Therefore, it is possible to reduce the current path and promote low ESL, and it is possible to realize a solid electrolytic capacitor having excellent transient response characteristics.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-239091

[Patent Document 2] WO/2011/02155

In the solid electrolytic capacitors disclosed in Patent Documents 1 and 2, first, a conductive adhesive is applied to an anode lead portion or an anode electrode plate, a conductive adhesive is applied to a cathode lead portion or a cathode electrode plate, and a capacitor element is overlapped with a terminal plate. It is produced by filling an insulating sealing resin in a gap to thermally harden it.

However, the gap between the capacitor element and the terminal block is small, and it is necessary to fill the sealing resin so as to surely cover the place where insulation is required, even in the case of high-level technology. Further, the addition of the sealing resin to this process results in a decrease in the production efficiency of the solid electrolytic capacitor.

Accordingly, the present invention has been made in order to solve the above problems. Provided is a method for producing a solid electrolytic capacitor and a solid electrolytic capacitor, which can more reliably and easily insulate between a capacitor element and a terminal plate with a sealing resin.

In order to achieve the above object, a aspect of the present invention relates to a method of manufacturing a solid electrolytic capacitor in which a capacitor element is superposed on a terminal plate, characterized in that the capacitor element is formed, and the capacitor element has a cathode portion that functions as a valve metal. a part of the area is increased to form a dielectric oxide film layer, a solid electrolyte layer, and an electrode lead-out portion; and an anode portion forming an electrode lead-out portion in a part of the valve action metal; forming the terminal plate, which is an anode electrode The plate and the cathode electrode plate are disposed on the same plane with a gap therebetween, and the insulating resin is interposed therebetween; and the uncured seal is disposed on the anode electrode plate of the terminal plate before the capacitor element is superposed on the terminal plate a resin, wherein a conductive adhesive is disposed on the cathode electrode plate of the terminal plate, and the capacitor element and the terminal plate are overlapped while being pressed, and the electrode lead portion is brought into contact with the anode electrode plate of the terminal plate to seal the electrode The resin is hardened with the aforementioned conductive adhesive.

The capacitor element and the terminal plate are heated while being superposed while being pressed, and the sealing resin and the conductive adhesive may be cured.

The conductive adhesive may also be solvent-free.

The electrode lead portion is a bump electrode that is sharpened at the tip end. When the electrode lead portion is overlapped, the bump electrode penetrates the sealing resin and passes through the bump electrode. The anode portion may be electrically connected to the anode electrode plate.

The bump electrode may be pressed against the anode electrode plate by pressurization when the sealing resin is cured.

Further, in order to achieve the above object, another aspect of the present invention relates to a solid electrolytic capacitor in which a capacitor element is superposed on a terminal plate, and is characterized in that it includes a plurality of bump electrodes and is erected on an anode of the capacitor element. a portion that is abutted to the anode electrode plate of the terminal plate and is squashed at the tip end; and a sealing resin interposed between the capacitor element and the terminal plate, penetrated by the bump electrode; and a conductive adhesive The cathode portion of the capacitor element and the cathode electrode plate of the terminal plate are connected to each other; and the bump electrode and the anode electrode plate of the terminal plate are connected by pressure bonding.

According to the present invention, it is not necessary to fill the gap between the capacitor element and the terminal plate to fill the sealing resin, and the process of sealing the solid electrolytic capacitor with the sealing resin is extremely simple. In addition, where it is necessary to be insulated, it can be insulated with a sealing resin.

Hereinafter, embodiments of the solid electrolytic capacitor of the present invention and a method of manufacturing the same will be described in detail with reference to the drawings.

(capacitor element)

1 is a schematic model view of a capacitor element, (a) being a plan view and (b) being a cross-sectional view. The capacitor element 10 shown in Fig. 1 is a substantially square plate having a thickness of about 100 to 500 μm, an anode lead portion 13 having an anode portion along each side of the square plate, and a cathode lead portion 14 having a cathode portion at the center portion. . The anode lead portion 13 and the cathode lead portion 14 are distinguished from each other by the separation layer 15. On the surface of the anode lead portion 13, a plurality of bump electrodes 16 are erected.

The capacitor element 10 is formed of a valve metal plate or a valve metal foil as the anode body 11. In the present embodiment, aluminum is taken as an example of the valve metal. An etching layer 12 is formed on a central portion of one surface of the anode body 11, and a dielectric oxide film to be a dielectric layer is formed on the etching layer 12, and a cathode lead portion 14 is formed on the surface. The cathode lead portion 14 is composed of a solid electrolyte layer, a graphite layer, and a silver paste layer.

The etching layer 12 is a porous layer whose area is increased by etching. For example, in the case of the anode body 11 having a thickness of about 100 μm, the etching layer 12 is formed to have a depth of about 40 μm. Therefore, the thickness of the layer which is not etched in the anode body is about 60 μm. Both end portions of the anode body 11 are unetched portions, and the unetched portions become the anode lead portions 13.

The dielectric oxide film is formed by anodization, and a dielectric oxide film made of alumina is formed on the aluminum surface (the inner surface of the etching layer 12) which is etched to form a porous layer. The anodic oxidation is performed by immersing the etching layer 12 in an aqueous solution such as boric acid or adipic acid, and applying a predetermined voltage.

The solid electrolyte layer is formed by sequentially immersing the anode body 11 in the poly The monomer solution and the oxidizing agent solution are pulled up from the respective liquids to carry out a polymerization reaction, whereby the respective liquids permeate into the inside of the etching layer 12 to be formed on the dielectric oxide film. The formation of the solid electrolyte layer can also be carried out by coating or discharging the polymerizable monomer solution and the oxidizing agent solution onto the etching layer 12. Further, a method of immersing or coating the anode body 11 in a mixed solution of a polymerizable monomer solution and an oxidizing agent may also be employed. Further, the solid electrolyte layer can be formed by an electrolytic polymerization production method used in the technical field of solid electrolytic capacitors, or a coating/drying dispersion of a conductive polymer or a soluble conductive polymer solution.

As the polymerizable monomer solution used in the method for forming a solid electrolyte, thiophene, pyrrole or a derivative thereof can be suitably used. Among the thiophene derivatives, 3,4-ethylenedioxythiophene is suitable. As the oxidizing agent, an aqueous solution of iron (II) p-toluenesulfonate, periodic acid or iodic acid dissolved in ethanol can be used.

The separation layer 15 is located at the boundary between the inner periphery of the anode lead portion 13 and the outer periphery of the cathode lead portion 14, so that the anode lead portion 13 of the cathode lead portion 14 is insulated from the cathode lead portion 14. The separation layer 15 is formed by applying an insulating resin between the anode lead portion 13 and the cathode lead portion 14. An insulating resin may also be applied to the outer periphery of the anode lead portion 13.

The bump electrode 16 is an example of an electrode lead portion, and the anode lead portion 13 is electrically connected to the anode electrode plate 22 of the terminal plate 20 to be described later, and has a quadrangular pyramid or a conical shape in which the tip end is sharpened, and the tip end is crushed by an external force. Flexible protruding electrode.

(terminal board)

2 is a schematic view of a terminal block, (a) is a plan view, and (b) is a cross-sectional view. The terminal block 20 shown in FIG. 2 is a terminal portion that is connected to the printed circuit board and has a mounting pad that closely matches the capacitor element 10. That is, in the terminal block 20, the cathode electrode plate 21 is provided at the center, and the anode electrode plate 22 is further provided to surround the four sides of the cathode electrode plate 21. The square anode electrode plate 22 and the cathode electrode plate 21 are insulated by an insulating resin 23.

The anode electrode plate 22 and the cathode electrode plate 21 are each formed of a thin metal plate. The metal plate is, for example, a thin copper plate having a thickness of about 5 to 100 μm, and may be a rolled copper foil or a copper alloy foil. The metal plate as the cathode electrode plate 21 has a square shape, and the metal plate as the anode electrode plate 22 has a square-shaped hole. The hole of the metal plate as the anode electrode plate 22 is larger than the square shape of the cathode electrode plate 21. Between the anode electrode plate 22 and the cathode electrode plate 21, the anode electrode plate 22 surrounds the cathode electrode plate 21, and is disposed on the same plane with a gap of about 0.1 mm.

The gap existing between the anode electrode plate 22 and the cathode electrode plate 21 is filled with the insulating resin 23 interposed therebetween, and the two metal plates are held in the same plane and integrated. In other words, the insulating resin 23 is an insulating member that electrically insulates the cathode electrode plate 21 from the anode electrode plate 22, and is also a bonding agent that integrates the cathode electrode plate 21 and the anode electrode plate 22. The insulating resin 23 can be, for example, a polyester resin, a polyimide resin, a liquid crystal polymer or the like, and its insulating property, adhesion between the two electrode plates 21 and 22, strength, and the like are suitable for use in a solid electrolytic capacitor.

In the terminal plate 20, the cathode electrode plate 21 and the anode electrode plate 22 are disposed on the same plane, and the gap portion is filled with the insulating resin 23 and thermally cured. Further, the insulating resin 23 may be applied to the peripheral edge of the surface of the cathode electrode plate 21 and the anode electrode plate 22 which are connected to the gap portion, in addition to the gap portion, to enhance the integration strength.

(Manufacturing method of solid electrolytic capacitor)

FIG. 3 is a schematic view showing the assembly relationship between the capacitor element 10 and the terminal block 20. As shown in FIG. 3, the solid electrolytic capacitor is formed so as to face the surface on which the anode lead portion 13 and the cathode lead portion 14 are formed, and the capacitor element 10 and the terminal plate 20 are overlapped. In the solid electrolytic capacitor, the anode lead portion 13 is assembled by an electrode lead portion such as a bump electrode 16, and the cathode lead portion 14 is assembled by a conductive adhesive.

4 is a schematic view showing a first step of manufacturing a solid electrolytic capacitor, wherein (a) is a side cross-sectional view and (b) is a plan view. First, as shown in FIG. 4( a ), the sealing resin 30 is applied by coating on the entire periphery of the mounting surface on the terminal plate 20 that overlaps the capacitor element 10 . For example, as shown in FIG. 4(b), the sealing resin 30 includes the entire surface of the anode electrode plate 22, and the sealing resin 30 is disposed by coating to cover the cathode electrode plate 21. It may also be configured to cover the periphery of the cathode electrode plate 21 with the sealing resin 30.

The sealing resin 30 is a thermosetting insulating resin, and fills a gap between the terminal plate 20 and the capacitor element 10. For example, the sealing resin 30 is an epoxy resin, a polyester resin, or a polyimide resin, and its insulating property. The adhesion, strength, and the like between the capacitor element 10 and the terminal block 20 are applied to a solid electrolytic capacitor.

The sealing resin 30 is adjusted in thickness to be coated so as to be at the same level as the height of the bump electrode 16 whose tip is flattened when pressurized. The sealing resin 30 can be formed by discharging or printing a gel-like sealing resin 30, or can be disposed so as to be attached to a film-shaped sealing resin 30.

Fig. 5 is a schematic view showing a second step of manufacturing a solid electrolytic capacitor, wherein (a) is a side sectional view and (b) is a plan view. After the portion other than the cathode electrode plate 21 is covered with the sealing resin 30, the conductive adhesive 40 is applied to the exposed surface of the cathode electrode plate 21.

As the conductive adhesive 40, it is preferred to use a gas to generate less solvent-free. The conductive adhesive 40 is obtained by dispersing a conductive filler in a binder such as a liquid resin which is rapidly hardened by heat.

As the conductive filler, gold powder, silver powder, copper powder, nickel powder, aluminum powder, plating powder, carbon powder, graphite powder, or the like of various particle diameters or shapes are used. The representative shape of the conductive filler is spherical or needle-like, scale-like, etc., but is not limited thereto. Further, a conductive filler having a different particle diameter or shape may be combined to be mixed.

The binder is mainly an organic binder, and an epoxy resin can generally be used. Further, urethane, polyfluorene oxide, acrylic acid, polyimine, and other thermosetting resins or thermoplastic resins may be used depending on the desired characteristics of the solid electrolytic capacitor or the place of use. In the case of an inorganic material, when a conductive adhesive 40 which is fired at a high temperature is used, a low melting point glass can be used as a secondary binder.

Further, in the first step to the third step, the process of applying the sealing resin 30 and the process of applying the conductive adhesive 40 may be performed in reverse order.

Fig. 6 is a schematic side sectional view showing a third step of manufacturing a solid electrolytic capacitor. After the conductive adhesive 40 is formed on the cathode electrode plate 21, the capacitor element 10 is placed on the terminal block 20, and is held under pressure, and then heated while maintaining the pressure for about 10 seconds or less.

At this time, the anode lead portion 13 is opposed to the anode electrode plate 22, the cathode lead portion 14 is opposed to the conductive adhesive 40, and the capacitor element 10 is placed on the terminal block 20. The bump electrode 16 is sharpened at the tip end, and thus passes through the sealing resin 30 to reach the anode electrode plate 22. As shown in FIG. 7, the bump electrode 16 reaching the anode electrode plate 22 is pressed against the anode electrode plate 22 due to the flexibility of the bump electrode 16 and the contraction stress of the sealing resin 30, and the tip end side is flattened. In order to seek electrical connection.

Further, the connection of the anode lead portion 13 may be such that the bump electrode 16 is connected to the anode electrode plate 22 as shown in FIG. For example, as shown in FIG. 8(a), the conductive adhesive 41 may be applied to the surface of the anode electrode plate 22 or the surface of the bump electrode 16 in advance, and the bump electrode 16 may be bonded to the anode electrode plate 22 by an adhesive. . Further, as shown in FIG. 8(b), a plating 42 such as gold may be applied to the surface of the anode electrode plate 22 in advance, and the bump electrode 16 and the plating may be metal-bonded by heat fusion.

(Effect)

Like this, the solid electrolytic capacitor is first placed on the terminal block 20 The sealing resin 30 is applied to the entire periphery of the carrier. Next, after the sealing resin 30 is applied, the capacitor element 10 is overlapped with the terminal block 20. Therefore, it is not necessary to fill the gap between the capacitor element 10 and the terminal block 20 with the sealing resin, and it is extremely easy to seal the solid electrolytic capacitor with the sealing resin 30. Further, where it is necessary to be surely insulated, it can be insulated by the sealing resin 30.

At this time, the sealing resin 30 is applied before the overlap, and it is conceivable that the gap between the capacitor element 10 and the terminal block 20 is filled with the sealing resin 30 before the conductive adhesive 40 is thermally cured. In this case, a solvent-free gas-free solvent is used as the conductive adhesive 40, whereby when the capacitor element 10 and the terminal plate 20 are pressurized while being heated, there is no fear of being generated from the conductive adhesive 40. A lot of gas. Therefore, even if the sealing resin 30 is applied before the capacitor element 10 is overlapped with the terminal block 20, a solid electrolytic capacitor having a good sealing performance can be manufactured.

Further, as long as the tip end sharpening bump electrode 16 is provided upright in the anode lead portion 13, the bump electrode 16 penetrates the sealing resin 30 to reach the anode electrode of the terminal block 20 even if the anode electrode plate 22 is covered with the sealing resin 30. Board 22. Therefore, even if the anode electrode plate 22 is covered with the sealing resin 30, there is no problem in electrical conduction. Therefore, the engineering of applying the sealing resin 30 can be simplified. Further, it is possible to more reliably insulate between the capacitor element 10 and the terminal block 20 where insulation is required.

The bump electrode 16 is crimped to the anode electrode plate 22 in a state where the tip end is flattened, and then heated and pressurized to apply the sealing resin 30 and The conductive adhesive 40 is hardened. The bump electrode 16 receives shrinkage stress from the sealing resin 30 or the conductive adhesive 40. Therefore, as long as the bump electrode 16 and the anode electrode plate 22 are crimped, the state of electrical conduction is maintained. Therefore, the bump electrode 16 can be pressed against the anode electrode plate 22, and the work can be simplified.

As described above, the embodiments of the present invention have been described as examples of the present invention, and the scope of the invention is not limited thereto, and various omissions, substitutions, and changes may be made without departing from the scope of the invention. The present invention and its modifications are intended to be included within the scope of the invention and the scope of the invention.

10‧‧‧ capacitor components

11‧‧‧Anode body

12‧‧‧ etching layer

13‧‧‧Anode lead-out

14‧‧‧Cathode lead-out

15‧‧‧Departure Department

16‧‧‧Bump electrode

20‧‧‧Terminal board

21‧‧‧Cathode electrode plate

22‧‧‧Anode electrode plate

23‧‧‧Insulating resin

30‧‧‧ Sealing resin

40‧‧‧ Conductive Adhesive

Fig. 1 is a schematic view showing a capacitor element, (a) being a plan view and (b) being a cross-sectional view.

2] A schematic diagram of a terminal block, (a) is a plan view, and (b) is a cross-sectional view.

[Fig. 3] Schematic diagram of the assembly relationship between the capacitor element and the terminal block.

Fig. 4 is a schematic view showing a first step of manufacturing a solid electrolytic capacitor, wherein (a) is a side sectional view and (b) is a plan view.

Fig. 5 is a schematic view showing a second step of manufacturing a solid electrolytic capacitor, wherein (a) is a side sectional view and (b) is a plan view.

Fig. 6 is a schematic side sectional view showing a third step of manufacturing a solid electrolytic capacitor.

Fig. 7 is a schematic view showing an example of connection of an anode lead portion.

Fig. 8 is a schematic view showing another example of the connection of the anode lead portions.

10‧‧‧ capacitor components

12‧‧‧ etching layer

13‧‧‧Anode lead-out

14‧‧‧Cathode lead-out

15‧‧‧Departure Department

16‧‧‧Bump electrode

20‧‧‧Terminal board

21‧‧‧Cathode electrode plate

22‧‧‧Anode electrode plate

23‧‧‧Insulating resin

30‧‧‧ Sealing resin

40‧‧‧ Conductive Adhesive

Claims (6)

A method of manufacturing a solid electrolytic capacitor, which is directed to a method of manufacturing a solid electrolytic capacitor in which a capacitor element is superposed on a terminal plate, characterized in that the capacitor element is formed, the capacitor element having a cathode portion which is a part of a valve metal Increasing, forming a dielectric oxide film layer, a solid electrolyte layer, and an electrode lead-out portion; and an anode portion forming an electrode lead portion in a part of the valve action metal to form the terminal plate, which is an anode electrode plate and a cathode The electrode plates are disposed on the same plane with a gap therebetween, and an insulating resin is interposed therebetween, and an unhardened sealing resin is disposed on the anode electrode plate of the terminal plate before the capacitor element is superposed on the terminal plate. a conductive adhesive is disposed on the cathode electrode plate of the terminal plate, and the capacitor element and the terminal plate are superposed on each other while being pressed, and the electrode lead portion is brought into contact with the anode electrode plate of the terminal plate, and the sealing resin and the sealing resin are The conductive adhesive hardens. The method of manufacturing a solid electrolytic capacitor according to the first aspect of the invention, wherein the capacitor element and the terminal plate are heated while being superimposed while being pressed, and the sealing resin and the conductive adhesive are cured. The method for producing a solid electrolytic capacitor according to claim 1 or 2, wherein the conductive adhesive is solvent-free. Solid electrolytic electricity such as any one of claims 1 to 3 In the method of manufacturing a container, the electrode lead portion is a bump electrode that is sharpened at the tip end, and when the electrode is overlapped, the bump electrode penetrates the sealing resin, and the anode portion and the anode electrode plate are electrically connected through the bump electrode. connection. The method of manufacturing a solid electrolytic capacitor according to the fourth aspect of the invention, wherein the bump electrode is pressed against the anode electrode plate by pressurization when the sealing resin is cured. A solid electrolytic capacitor is a solid electrolytic capacitor in which a capacitor element is superposed on a terminal plate, and is characterized in that it includes a plurality of bump electrodes that are erected on an anode portion of the capacitor element and abuts against an anode of the terminal plate. The electrode plate is squashed at the tip end; a sealing resin interposed between the capacitor element and the terminal plate, penetrated by the bump electrode; and a conductive adhesive interposed between the cathode portion of the capacitor element and the terminal plate Between the cathode electrode plates, the bump electrodes and the anode electrode plates of the terminal plates are connected by pressure bonding.