JPH0590096A - Manufacture of chip type solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To provide a manufacture of a chip type solid electrolytic capacitor, where the alignment of electrode polarities can be performed easily and the exfoliation of the junction interface between the anode lead wire and the anode metallic layer can be prevented. CONSTITUTION:An anode lead wire 12, which is led out of the anode body 11 consisting of the valve acting metal constituting a capacitor element 11a, is attached to a metallic ribbon 13, and a series of manufacturing steps from the formation of a dielectric oxide film to an anode body 11 to the formation of solder metallic layers 21 and 22 are performed, with the anode lead wire 12 being attached to the metallic ribbon 13, and at the final stage of manufacture, the anode lead wire is cut form the metallic piece 13 into individual pieces.

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 chip solid electrolytic capacitor.

[0002]

2. Description of the Related Art In recent years, the number of chip parts has been rapidly increasing due to the miniaturization of electronic equipment and the progress of surface mounting technology. Even in the chip-type solid electrolytic capacitor, the miniaturization of the chip component itself is required as the size and capacity of the chip solid electrolytic capacitor are increasing.

A conventional method for manufacturing a chip-shaped tantalum solid electrolytic capacitor will be described below with reference to the flow chart of FIG.

First, an anode lead wire 2 drawn from a capacitor element 1 made of a porous anode body made of a valve metal is attached to a metal ribbon 3. From the next step, a metal ribbon is handled in units of 3 and a dielectric oxide film, an electrolyte layer, a cathode layer 4 composed of a carbon layer and a silver coating layer are sequentially laminated on the surface of a porous anode body made of a valve metal. The capacitor element 1 is formed. Next, a cathode conductor layer 5 is formed on a portion of the cathode device 4 opposite to the anode lead wire 2. Then, the capacitor element 1 and the cathode conductor layer 5 are covered with an exterior resin 6 so that the anode lead wire 2 is drawn out to one side, and then the cathode side of the exterior resin 6 is exposed to the cathode conductor layer 5. Cut or grind. Next, the anode metal layer 7 and the cathode metal layer 8 are formed on the anode lead-out surface 2a and the cathode lead-out surface 5a. In this case, in the prior art, the anode lead wire 2 was cut to separate the chip parts from the metal ribbon 3 before or after forming the anode metal layer 7 and the cathode metal layer 8. Then, after that, the anode metal layer 7 and the cathode metal layer 8 are covered with the solder metal layers 9 and 10 to be commercialized.

[0005]

However, in such a method for manufacturing a chip-shaped tantalum solid electrolytic capacitor, the anode lead wire 2 is cut to form the metal ribbon 3 before the anode metal layer 7 is formed on the anode lead wire 2. If the chip parts are separated into individual pieces, it is necessary to distinguish the polarities of the anode and the cathode from the shape of the chip parts in the subsequent process and align them.
The post process becomes complicated. After forming the anode metal layer 7 on the anode lead wire 2, the anode lead wire 2 is cut to form the metal ribbon 3
Further, when the chip parts are diced into individual pieces, there is a problem that the bonding interface between the anode lead wire 2 and the anode metal layer 7 is separated due to the cutting stress, and tan δ increases.

The present invention solves the above-mentioned problems of the prior art, in which the polarities of the electrodes can be easily aligned and the peeling of the bonding interface between the anode lead wire and the anode metal layer can be prevented. An object of the present invention is to provide a method for manufacturing a solid electrolytic capacitor.

[0007]

In order to achieve the above object, a method of manufacturing a chip solid electrolytic capacitor of the present invention comprises:
A capacitor element having an anode lead wire and having a dielectric oxide film, an electrolyte layer, and a cathode layer sequentially laminated on the surface of an anode body made of a valve metal, and the capacitor element having the anode lead wire and the cathode lead wire. The exterior resin covering the parts so as to be exposed in opposite directions, the anode lead-out surface of the exterior resin,
An anode lead derived from an anode body made of a valve action metal that constitutes the capacitor element, comprising an anode lead wire and an anode metal layer formed on the cathode portion of the exterior resin and a solder metal layer formed via the cathode metal layer. The wire is attached to the metal ribbon, and the series of manufacturing steps from the formation of the dielectric oxide film on the anode body to the formation of the solder metal layer are performed with the metal ribbon attached, and at the end of the manufacturing, the anode lead wire is cut to remove the metal. The ribbon is made into individual pieces.

[0008]

According to the above-described manufacturing method, the anode lead wire, which is led out from the anode body made of the valve metal that constitutes the capacitor element, is attached to the metal ribbon, and the dielectric oxide film is formed on the anode body to form the solder metal. Since the series of manufacturing processes up to layer formation is performed with the metal ribbon attached, and the anode lead wire is cut at the end of manufacture to separate the metal ribbon into individual pieces, the adhesion strength formed on the anode lead wire The weak anode metal layer is subject to cutting stress in a state of being covered and protected by the solder metal layer, which prevents an increase in tan δ due to peeling of the bonding interface between the anode lead wire and the anode metal layer. In addition, the polarity of the electrodes can be easily aligned by cutting the lead wire of the anode and separating the metal ribbon into individual pieces in the final step of manufacturing the capacitor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a finished chip tantalum solid electrolytic capacitor according to an embodiment of the present invention.
FIG. 2 is a flow chart showing a method of manufacturing the same chip-shaped tantalum solid electrolytic capacitor.

In FIGS. 1 and 2, reference numeral 11 denotes a porous anode body formed by molding and sintering tantalum metal powder which is a valve metal, and a dielectric oxide film is formed on the surface of the anode body 11 by anodic oxidation. Then, an electrolyte layer of manganese dioxide or the like is formed on this surface. The anode lead wire 12 is made of tantalum wire and is led out from the anode body 11. A series of processing steps on the surface of the anode body 11 are performed in a state where the anode lead wire 12 is connected to the metal ribbon 13 made of stainless steel. 14 is an anode lead wire 1
2 is a Teflon plate attached to the anode 2, and the Teflon plate 14 is an insulating plate that prevents manganese dioxide from creeping up and adhering to the anode lead wire 12 when the electrolyte layer is formed on the anode body 11. A cathode layer 15 made of a carbon layer and a silver coating layer is formed on the electrolyte layer of the anode body 11 by a dipping method.
Are sequentially laminated to form the capacitor element 11a. Further, in the portion of the capacitor element 11a located on the side opposite to the anode lead wire 12 of the cathode layer 15, the cathode conductor layer 16 is sequentially laminated by being dipped in a coating material containing silver powder as a main component. After that, the capacitor element 1 in this state
1a and the cathode conductor layer 16 are immersed in a silicone-based or fluorine-based water-repellent resin 17 so that the capacitor element 11a and the cathode conductor layer 16 are entirely water-repellent resin 17.
To be covered with.

Next, the capacitor element 11a and the cathode conductor layer 16 are made of epoxy resin by a transfer molding method so that the anode lead wire 12 is drawn out to one side.
After packaging, the packaging resin 18 is cut or ground so that the cathode conductor layer 16 is exposed. After that, after pretreatment of alkali degreasing, chemical etching and catalyst application, the anode lead wire 12 and the anode lead surface 12 are formed by electroless Ni plating.
The anode metal layer 19 made of Ni and the cathode metal layer 20 made of Ni are formed on the respective surfaces of a, the cathode lead-out surface 16a, and the molded body of the exterior resin 18. In this case, the thickness of the anode metal layer 19 and the cathode metal layer 20 is 0.5 to 5.0 μ.
The range of m is excellent in the bonding strength with the base. Then, solder metal layers 21 and 22 are provided on the both electrodes through the anode metal layer 19 and the cathode metal layer 20. In the final manufacturing step, the anode lead-out wire 12 is cut into individual pieces from the metal ribbon 13 so that the chip-shaped tantalum solid electrolytic capacitor thus manufactured is located at the external product dimension position, and after the inspection, it is completed.

In the manufacturing method according to the embodiment of the present invention described above, the anode lead wire 12 led out from the anode body 11 made of the valve metal which constitutes the capacitor element 11a.
Is attached to the metal ribbon 13, and a series of manufacturing steps from the formation of the dielectric oxide film on the anode body 11 to the formation of the solder metal layers 21 and 22 are carried out while the metal ribbon 13 is attached. Since the lead wire 12 is cut into individual pieces from the metal ribbon 13, the anode metal layer 19 formed on the anode lead wire 12 and having low adhesion strength is formed.
Is subjected to a cutting stress in a state where it is covered and protected by the solder metal layer 21 on the anode side, whereby peeling of the bonding interface between the anode lead wire 12 and the anode metal layer 19 can be prevented. The increase in tan δ due to this peeling can be prevented.

Further, since the anode lead wire 12 is cut in the final step of manufacturing the capacitor, the polarities of the electrodes can be easily aligned.

FIG. 3 compares the tan δ of the chip-shaped tantalum solid electrolytic capacitor obtained by the manufacturing method in one embodiment of the present invention with the tan δ of the chip-shaped tantalum solid electrolytic capacitor obtained by the conventional manufacturing method. It is a graph showing the results, and as is clear from FIG. 3, the one using the conventional manufacturing method shows an increase in tan δ, but the one using the manufacturing method in one embodiment of the present invention shows The increase can be prevented.

In the embodiment of the present invention described above, the cathode conductor layer 16 is provided separately from the cathode layer 15 of the capacitor element 11a, but when the capacitor element 11a is covered with the exterior resin 18. , The cathode layer 1
5 may be directly exposed from the end surface of the exterior resin 18, and the point is that the cathode portion is exposed from the end surface of the exterior resin 18.

[0017]

As described above, according to the method for manufacturing the chip solid electrolytic capacitor of the present invention, the anode lead wire derived from the anode body made of the valve metal constituting the capacitor element is attached to the metal ribbon, and Perform a series of manufacturing steps from forming the dielectric oxide film on the anode body to forming the solder metal layer with the metal ribbon attached, and at the end of manufacturing, cut the anode lead wire to separate it from the metal ribbon. Therefore, the anode metal layer formed on the anode lead wire and having a weak adhesion strength is subjected to cutting stress in a state of being covered and protected by the solder metal layer, whereby the anode lead wire and the anode metal layer are It is possible to prevent an increase in tan δ due to the peeling of the bonding interface of, and cut the anode lead wire to separate it from the metal ribbon in the final step of manufacturing the capacitor, and Column also those which can be easily performed.

[Brief description of drawings]

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

FIG. 2 is a flow chart of a method for manufacturing the same chip-shaped tantalum solid electrolytic capacitor.

FIG. 3 is a graph showing a comparison of tan δ of the chip-shaped tantalum solid electrolytic capacitor obtained by the manufacturing method and the chip-shaped tantalum solid electrolytic capacitor obtained by the conventional manufacturing method in one example of the present invention.

FIG. 4 is a flow chart of a method for manufacturing a conventional chip-shaped tantalum solid electrolytic capacitor.

[Explanation of symbols]

 11 Anode body 11a Capacitor element 12 Anode lead wire 13 Metal ribbon 15 Cathode layer 18 Exterior resin 19 Anode metal layer 20 Cathode metal layer 21, 22 Solder metal layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Junichi Kurita 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] Claim: What is claimed is: 1. A capacitor element comprising an anode lead wire and an anode body made of a valve metal, on which a dielectric oxide film, an electrolyte layer and a cathode layer are sequentially laminated. The exterior resin covering the anode lead wire and the cathode portion so as to be exposed in the opposite direction, the anode lead surface of the exterior resin, the cathode lead wire, and the cathode metal layer and the cathode metal layer formed on the cathode portion of the exterior resin. And a solder metal layer formed through the anode metal, and an anode lead wire derived from an anode body made of a valve metal constituting the capacitor element is attached to a metal ribbon, and a dielectric oxide film is formed on the anode body to form a solder. A chip-shaped solid electrolytic capacitor characterized by performing a series of manufacturing steps up to metal formation with the metal ribbon attached, and cutting the anode lead wire at the end of the manufacturing to separate the metal ribbon into individual pieces. The method of production.