JPH05136008A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To make it possible to improve the yield at the time of production by surely preventing from creeping up of the mother liquor of a semiconductor to valve action wire, and to provide a solid electrolytic capacitor which permits to improve remarkably its reliability at the time of actual use on user side. CONSTITUTION:Forming is made by implanting valve action wire in valve action metallic powder, and then an insulating material 13 with water repellency characteristics is bonded, with the valve action wire 12 penetrating therethrough, to the root of sintered-electrode 11 on which the valve action wire has been implanted.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, in the parts industry, there has been an increasing demand for light, thin, short, compact, and highly reliable electric products, and even tantalum solid electrolytic capacitors, which are electronic parts used in such products, have the heat generated during board mounting. The demand for higher reliability against stress is increasing.

A conventional tantalum solid electrolytic capacitor, in particular, a chip type tantalum solid electrolytic capacitor will be described below with reference to FIG. In FIG. 4, reference numeral 1 denotes an electrode body, and this electrode body 1 is constituted by implanting a valve action metal wire 2 made of tantalum in a valve action metal powder made of tantalum, molding it, and sintering it. The valve action metal wire 2 serves as an anode lead wire, and a water repellent insulating member 3 is inserted in the valve action metal wire 2 in order to prevent the semiconductor mother liquor from creeping up. Further, a dielectric layer is formed on the surface of the electrode body 1 by an electrochemical reaction (anodic oxidation) in an electrolytic solution, and then a semiconductor layer made of manganese dioxide which is a solid electrolyte by thermal decomposition on the dielectric layer. And a cathode layer composed of a carbon layer and a silver coating layer is formed on the semiconductor layer. Also, the valve action metal wire 2 is connected to an anode lead-out terminal 4 led out to the outside, and the cathode layer is connected to a cathode lead-out terminal 5 led out to the outside, and the anode lead-out terminal 4 and the cathode lead-out terminal are connected. The outside of the electrode body 1 is molded with the exterior resin 6 so that a part of the terminal 5 is exposed, and then the anode lead terminal 4 and the cathode lead terminal 5 are bent along both side surfaces and the bottom surface of the exterior resin 6. As a result, a chip-type tantalum solid electrolytic capacitor was constructed.

[0004]

However, the insulating member 3 having water repellency for preventing the rising of the semiconductor mother liquor in the above-mentioned conventional structure is simply inserted into the valve action metal wire 2. When the dielectric layer or the semiconductor layer made of manganese dioxide is formed on the surface of the electrode body 1, the insulating member 3 having water repellency is lifted and the adhesion between the valve metal wire 2 and the electrode body 1 is deteriorated. As a result, the semiconductor mother liquor causes the anode lead-out terminal 4 of the valve action metal wire 2 to
The phenomenon of climbing up to the side sometimes occurred. If the assembling is performed in this state, there is a problem that a leakage current failure occurs or, in the worst case, a short circuit occurs and the capacitor does not function.

The present invention solves such a problem, and it is possible to surely prevent the semiconductor mother liquor from creeping up to the valve action metal wire to improve the yield at the time of manufacturing, and at the same time for the user. It is an object of the present invention to provide a solid electrolytic capacitor that can significantly improve reliability during actual use.

[0006]

In order to achieve the above object, a solid electrolytic capacitor of the present invention comprises an electrode body obtained by implanting a valve metal wire in a valve metal powder, molding the metal wire, and sintering the metal wire. The valve body is provided with an insulating member having water repellency fixed to the root of the electrode body where the valve metal line is implanted, and a dielectric layer is further formed on the surface of the electrode body. , A semiconductor layer and a cathode layer are sequentially formed.

[0007]

According to the above construction, a valve-repellent metal powder is planted with a valve-acting metal wire, molded, and sintered. Since the insulating member having is fixed in a state of penetrating the valve action metal wire, it means that the insulating member having water repellency floats up when the dielectric layer and the semiconductor layer are formed on the surface of the electrode body. As a result, since it is possible to reliably prevent the semiconductor mother liquor from creeping up to the anode lead terminal side of the valve action metal wire, the yield at the time of manufacturing is improved, and furthermore, the occurrence of leakage current defects is eliminated. The reliability when actually used by the user can be significantly improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 11 denotes an electrode body, and this electrode body 11 is constituted by implanting a valve action metal wire 12 made of tantalum in a tantalum metal powder which is a valve action metal, molding and sintering it. . Reference numeral 13 denotes an insulating member having water repellency. This insulating member 13 has the valve action metal wire 12 at the root of the electrode body 11 in which the valve action metal wire 12 is implanted.
It is fixed by an epoxy adhesive 14 which is excellent in heat resistance and chemical resistance in a state of being penetrated through. Further, a dielectric layer is formed on the surface of the electrode body 11 by an electrochemical reaction (anodic oxidation) in an electrolytic solution, and then a semiconductor layer made of manganese dioxide which is a solid electrolyte by thermal decomposition is formed on the dielectric layer. And a cathode layer composed of a carbon layer and a silver coating layer is formed on the semiconductor layer.

The valve action metal wire 12 is connected to an anode lead-out terminal 15 led out to the outside, and the cathode layer is connected to a cathode lead-out terminal 16 led out to the outside. The outside of the electrode body 11 is molded with the exterior resin 17 so that a part of the cathode extraction terminal 16 is exposed, and then the anode extraction terminal 15 and the cathode extraction terminal 16 are formed along both side surfaces and the bottom surface of the exterior resin 17. The chip-type tantalum solid electrolytic capacitor is constructed by bending it.

FIG. 2 shows a method of fixing the water-repellent insulating member 13. First, when the electrode body 11 is aligned and fixed to the metal plate 18 by welding or the like, the water-repellent insulating member 1 is formed.
3 is penetrated through the valve action metal wire 12 of the electrode body 11, and an epoxy adhesive 14 is applied to the upper surface of the insulating member 13. Then, in a hot air drying oven at about 125 ° C for 10 minutes
The epoxy adhesive 14 can be put in for 15 minutes.
Is dried and cured, and the water-repellent insulating member 13 is fixed to the root portion of the electrode body 11 in which the valve metal wire 12 is implanted. After that, a dielectric layer, a semiconductor layer made of manganese dioxide, a cathode layer made of a carbon layer and a silver coating layer are sequentially formed on the surface of the electrode body 11.

Table 1 shows that the insulating member 13 is fixed to the valve action metal wire 12 as in the embodiment of the present invention and that the insulating member 3 is not fixed to the valve action metal wire 2 as in the conventional example. 3 shows a comparison of the number of defective rising members of the insulating member.

[0012]

[Table 1]

As is clear from this (Table 1), in the embodiment of the present invention, the insulating member 13 is connected to the valve action metal wire 12.
Since it is adhered to the insulating member 13, the rising defect of the insulating member 13 can be eliminated.

Table 2 shows that semiconductor mother liquor was prevented from creeping up to the valve action metal wire as in the embodiment of the present invention.
FIG. 5 shows a comparison of the number of defective leakage currents in the initial stage after assembly is completed with a case where the insulating member is not fixed to the valve action metal wire as in the conventional example.

[0015]

[Table 2]

As is clear from this (Table 2), in the embodiment of the present invention, the initial leakage current defective rate after the assembly is completed can be greatly reduced as compared with the conventional example.

FIG. 3 is a comparison of the leakage currents of the solid electrolytic capacitor in the embodiment of the present invention and the conventional solid electrolytic capacitor after assembling and after completion and in the solder bath at 260 ° C.
It shows the leakage current comparison when dipping for 0 seconds.

As is clear from FIG. 3, the embodiment of the present invention can reduce the leakage current as compared with the conventional example.

[0019]

As described above, according to the solid electrolytic capacitor of the present invention, the valve action metal wire of the electrode body formed by implanting the valve action metal wire in the valve action metal powder and molding and sintering is implanted. Since the insulating member having water repellency is fixed to the provided root portion while penetrating the valve action metal wire, water repellency can be prevented when forming the dielectric layer and the semiconductor layer on the surface of the electrode body. Since the insulating member that it has does not float up, as a result, it is possible to reliably prevent the semiconductor mother liquor from creeping up to the anode lead terminal side of the valve action metal wire, improving the manufacturing yield and further preventing leakage. Since the occurrence of current failure is eliminated, the reliability of the user during actual use can be significantly improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a chip-type tantalum solid electrolytic capacitor showing an embodiment of the present invention.

FIG. 2 is a plan view showing a method of fixing an insulating member having water repellency in the same capacitor.

FIG. 3 is a characteristic diagram showing a comparison of leakage current between a solid electrolytic capacitor according to an embodiment of the present invention and a conventional solid electrolytic capacitor.

FIG. 4 is a sectional view of a conventional chip type tantalum solid electrolytic capacitor.

[Explanation of Codes] 11 Electrode Body 12 Valve Metal Wire 13 Insulation Member 14 Epoxy Adhesive

Claims (2)

[Claims] 1. A valve-action metal powder is provided with an electrode body formed by implanting and molding a valve-action metal wire, and the electrode body is provided with a sintered body. A solid electrolytic capacitor in which an insulating member having water repellency is fixed in a state of penetrating the valve action metal wire, and a dielectric layer, a semiconductor layer, and a cathode layer are sequentially formed on the surface of the electrode body. 2. The fixing of the water-repellent insulating member is performed by penetrating the water-repellent insulating member through the valve metal wire, applying an epoxy adhesive to the insulating member, and curing the adhesive. The solid electrolytic capacitor according to claim 1, wherein