JPH07297084A - Method for manufacturing chip solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent a suction mistake on mounting by providing a cut-out so that the resin of the electrode formation part of an encapsulation resin layer becomes thin in the transfer mold system and covering it with an encapsulation resin layer. CONSTITUTION:When forming an encapsulation resin layer 2a at a capacitor element 1 where a dielectric oxide layer, electrolytic layer, carbon layer, and cathode layer are formed successively on the surface of an anode body consisting of a valve-operation metal with an anode leading wire, an encapsulation resin layer where a cut-out 2b is provided so that only the electrode formation part of the encapsulation resin layer on the electrode formation surface of a chip solid electrolytic capacitor becomes thin is covered by the transfer mold system so that the anode lead wire and the cathode layer are partially exposed. Then, by applying silver paste to the cut-out 2b of the encapsulation resin 2a, an electrode ground layer 3 is formed and an electroless plating layer 4 and an electrolytic solder plated layer 5 are formed on the electrode ground layer 3, thus constituting an anode metal layer and a cathode metal layer and hence achieving a positive and automatic packaging.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A conventional chip-shaped solid electrolytic capacitor is
As in the embodiment of Japanese Patent Laid-Open No. 5-226193, FIG.
As shown in FIG. 1, a capacitor element 1 is constructed by forming a dielectric oxide film, an electrolyte layer, a carbon layer and a cathode layer on the surface of an anode body made of a valve metal having an anode lead wire. Anode metal composed of an electrode underlayer 3, an electroless plating layer 4, an electrolytic solder plating layer 5, etc. after covering the outside of the capacitor element 1 with an exterior resin layer 2a so that the anode lead wire and a part of the cathode layer are exposed. Layer and the cathode metal layer were formed.

[0003]

However, the above-mentioned conventional chip-shaped solid electrolytic capacitor has, for example, an electrode underlayer such as a silver paste, an electroless plating layer, and
By the electrolytic solder plating layer, when forming the anode metal layer and the cathode metal layer, on the electrode formation surface of the chip-shaped solid electrolytic capacitor, the electrode underlayer, the electroless plating layer, the thickness of each layer of the electrolytic solder plating layer is accumulated, Total about 0.05m
The thickness of the anode metal layer and the cathode metal layer of 0.10 mm from m protrudes from the exterior resin surface. Further, even when a multiple plating layer is formed by an electroless plating layer or the like to form an anode metal layer and a cathode metal layer, a total of about 0.03 mm to 0.
The thickness of the anode metal layer and the cathode metal layer of 05 mm protrudes from the exterior resin surface.

For this reason, a step is formed on the electrode forming surface of the chip solid electrolytic capacitor, and when carrying by the suction nozzle during automatic mounting, a suction air leak occurs between the suction nozzle and the upper surface of the chip solid electrolytic capacitor. In some cases, it may occur, which is one of the causes of a suction error during mounting. In addition, the surface of the chip-shaped solid electrolytic capacitor, which is located below the chip solid contacting the substrate, has poor stability when mounted on the substrate, which is one of the causes of the mounting failure and the occurrence of the Tsumstone phenomenon during soldering. In addition, the projection on the side of the chip solid electrolytic capacitor has an image recognition error during automatic mounting.
As a result, the mounting workability was poor.

The present invention solves the above-mentioned conventional problems, and provides a small chip-shaped solid electrolytic capacitor which is excellent in mountability during automatic mounting and which can prevent the occurrence of the Tsumstone phenomenon. The purpose is to do.

[0006]

In order to achieve the above object, the chip solid electrolytic capacitor of the present invention is not a metal plate, but an anode metal layer and a cathode metal layer formed by a conductive paint or a plating layer, and an exterior. Cutouts are formed in the exterior resin layer of each part where the anode metal layer and the cathode metal layer are formed so that the resin layer is flush with the resin layer, and the anode lead wire and the cathode layer are partially exposed. Then, after that, it is provided with an anode metal layer and a cathode metal layer composed of either one of the conductive paint and the plating layer or a combination thereof.

That is, a dielectric oxide film, an electrolyte layer, and an electrolyte layer are formed on the surface of an anode body made of a valve metal having an anode lead wire.
A capacitor element in which a carbon layer and a cathode layer are sequentially formed,
An exterior resin layer that covers the capacitor element by a transfer mold method, and is drawn out of the exterior resin layer,
It is composed of an anode metal layer and a cathode metal layer connected to the anode lead wire and the cathode layer, respectively, and the anode metal layer and the cathode metal layer are composed of one or a combination of a conductive paint layer and a plating layer. And a chip-shaped solid electrolytic capacitor characterized in that a notch is formed in the exterior resin layer in a portion where the anode metal layer and the cathode metal layer are formed so as to be flush with the outer surface of the exterior resin layer. is there. Further, the position where the cutout portion of the exterior resin layer of the portion where the anode metal layer and the cathode metal layer are formed is formed on the substrate ground surface of the chip-shaped solid electrolytic capacitor during mounting, the suction surface of the suction nozzle, and both side surfaces. The feature is that it is provided.

[0008]

According to the above structure, since the notch is provided in the exterior resin layer, for example, the electrode underlayer, the electroless plating layer,
Even when an anode metal layer and a cathode metal layer composed of electrolytic solder plating layers are formed, each surface of the chip-shaped solid electrolytic capacitor becomes flat.
In addition, it is possible to prevent the occurrence of a mounting failure and a tombstone phenomenon by improving the stability when mounting on the board, and to prevent the image recognition error from occurring, so that reliable automatic mounting can be performed.

[0009]

Embodiment 1 An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a chip solid electrolytic capacitor according to an embodiment of the present invention, and FIG. 2 is a perspective view showing the shape after forming an exterior resin layer.

In FIG. 1 and FIG. 2, in this capacitor element 1, a dielectric oxide film, an electrolyte layer, a carbon layer, and a cathode layer are sequentially formed on the surface of an anode body made of a valve metal having an anode lead wire. When the exterior resin layer 2a is formed on the capacitor element 1, only the electrode forming portion of the exterior resin layer on the electrode forming surface of the chip solid electrolytic capacitor is thinned by about 0.070 mm as shown in FIG. The exterior resin layer provided with the cutout portion 2b was covered by a transfer mold method so that the anode lead wire and a part of the cathode layer were exposed.

Next, the electrode base layer 3 is formed by applying a silver paste by dipping to the electrode forming portion of the exterior resin layer, that is, the cutout portion 2b of the exterior resin layer 2a so as to have a thickness of about 40 μm. And the electroless plating layer 4 is formed on the electrode base layer 3 to have a film thickness of about 10 μm.
An electrolytic solder plating layer 5 having a film thickness of about 20 μm was formed to form an anode metal layer and a cathode metal layer, and a chip solid electrolytic capacitor was manufactured.

At this time, when the electrode base layer 3, the electroless plating layer 4, and the electrolytic solder plating layer 5 are formed to form the anode metal layer and the cathode metal layer, the electrode forming portion of the exterior resin layer is thinned and cut. Since the cutout portion 2b is provided, the exterior resin layer 2a and the anode metal layer and the cathode metal layer are flush with each other, that is, each surface of the chip solid electrolytic capacitor is flat. Air leaks from the contact surface of the suction nozzle are eliminated, the stability when mounted on the board is improved, and it is possible to prevent mounting failures and the occurrence of a tombstone phenomenon. Will not occur and reliable automatic mounting will be possible.

In the first embodiment, the anode metal layer and the cathode metal layer are made of a combination of conductive paint and plating. However, by forming at least one or more layers of either conductive paint or plating. You may comprise. However, the depth of the cut portion 2b, that is, the thickness of the exterior resin layer of the electrode forming portion needs to be changed according to the thickness of the constituent materials of the anode metal layer and the cathode metal layer. The position and shape of the cutout 2b may be changed according to the formation and shape of the anode metal layer and the cathode metal layer.

[0014]

As described above, according to the chip solid electrolytic capacitor of the present invention, the cutout portion 2b is provided by the transfer molding method so that the resin thickness of the electrode forming portion of the exterior resin layer 2a is reduced. As a result of coating the layers, for example, the electrode underlayer 3, the electroless plating layer 4, the electrolytic solder plating layer 5
Even when an anode metal layer and a cathode metal layer made of are formed,
Since each surface of the chip solid electrolytic capacitor is flat,
Achieves prevention of defective mounting and tombstone phenomenon during soldering, and improved image recognition accuracy.
Reliable automatic mounting is possible.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention after forming an exterior resin layer of a chip solid electrolytic capacitor.

FIG. 2 is a sectional view of a chip solid electrolytic capacitor showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional chip solid electrolytic capacitor.

[Explanation of symbols]

 1 Capacitor Element 2a Exterior Resin Layer 2b Notch 3 Electrode Base Layer 4 Electroless Plating Layer 5 Electrolytic Solder Plating Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01G 9/24 C

Claims (2)

[Claims] 1. A capacitor element in which a dielectric oxide film, an electrolyte layer, a carbon layer, and a cathode layer are sequentially formed on the surface of an anode body made of a valve metal having an anode lead wire, and a transfer mode method. The external resin layer covering the capacitor element with, and the anode metal layer and the cathode metal layer drawn out of the external resin layer and connected to the anode lead wire and the cathode layer, respectively, the anode metal layer and the cathode metal layer. The layer is composed of either one of a conductive paint layer and a plating layer or a combination thereof, and a portion of the portion where the anode metal layer and the cathode metal layer are formed so as to be flush with the outer surface of the exterior resin layer. A chip solid electrolytic capacitor having a notch formed in an exterior resin layer. 2. A substrate grounding surface of a chip solid electrolytic capacitor, a suction surface of a suction nozzle, and both side surfaces of a chip solid electrolytic capacitor at the time of mounting a position where a cutout portion of an exterior resin layer of a portion where an anode metal layer and a cathode metal layer are formed is mounted. The chip-shaped solid electrolytic capacitor according to claim 1, wherein the chip-shaped solid electrolytic capacitor is provided in and.