JPS6155243B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a chip-shaped solid electrolytic capacitor.

Conventionally, chip-shaped solid electrolytic capacitors that are attached to printed circuit boards or the like as face bonding have been coated with resin by transfer molding, but these have been large in size and expensive. In addition, there was a bare type that was not transfer molded and had a solderable metal terminal welded to the lead drawn out from the anode body of the capacitor element, but it had poor dimensional accuracy and low mechanical strength.
It was difficult to automate the attachment to the printed circuit board. In addition, all of the above products involve welding metal terminals to the lead-out leads, and if you try to cut the lead-out leads short, the oxide film will be damaged during handling, resulting in an increase in leakage current; This resulted in the drawback that the lead-out leads could break during handling.

Therefore, in the final process of manufacturing the main body 3 of the chip-shaped solid electrolytic capacitor, which has the lead-out lead 2 connected to the power supply bar 1 by welding or the like, as shown in Fig. 1, the lead-out lead is cut off as shown in Fig. 2. In this case, as shown in Figure 3,
The lead 2 is pulled out by the upper and lower holding jigs 4a and 4b.
In order to cut the lead-out lead 2 by lowering the cutting teeth 5, it is not possible to cut it shorter than the width l of the holding jigs 4a and 4b, and the same problem as described above remains depending on the handling. Ta.

The present invention solves the above-mentioned problems and provides a chip-shaped solid electrolytic capacitor that is small, easy to manufacture, and has excellent electrical characteristics.

The present invention will be described below with reference to embodiments shown in FIGS. 4 to 6.

First, as shown in FIG. 4, the lead-out leads 2 of a plurality of prismatic, cylindrical, etc. anode bodies 6 made of valve metal such as tantalum or aluminum having lead-out leads 2 are welded to the power supply bar 1, and the anode A dielectric oxide film 7 is formed on the surface of the body 6, and a semiconductor solid electrolyte layer 8 such as manganese dioxide and a cathode conductive layer 9 such as carbon and silver paste are sequentially formed on the film. Next, a reinforcing resin 10 such as epoxy is applied to the lead-out portion of the lead-out lead 1 and cured to form a resin layer 11 so as to selectively cover the anode body 6 . Next, a conductive layer 12 such as silver paste is applied to the cathode side electrode portion at the bottom of the anode body 2 and hardened. At this time, the conductive layer 12 is also applied to the anode side and hardened. Next, in order to separate the lead-out lead 2 from the power supply bar 1, the lead-out lead 2 is interposed between the upper mold 13 and the lower mold 14, each having a V-shaped tip as shown in FIG. Notches 2b are provided in a plane parallel to the plane of 1. This notch 2b is desirably formed in a range of 15 to 90% of the cross-sectional area of the lead-out lead 2. In other words, the conductive lead is usually made of metal such as tantalum or aluminum with a round or square cross section. If it is less than 15% of the cross-sectional area of the lead-out lead 2, the number of bends before cutting will increase, and if it exceeds 90%, the lead-out lead 2 is likely to bend during handling during the manufacturing process, which may cause problems in the subsequent process. This will hinder your work. Next, an electroless plating process of nickel, copper, etc. is performed to form an electroless plating layer on the above-mentioned conductive layer 12 and the lead-out lead 2 with the notches 2b formed on the surface. Thereafter, after contacting with molten solder to form a solder layer 15 and aging treatment, the lead-out lead 2 is bent and cut from the power supply bar as shown in FIG.

The method for manufacturing a chip-shaped solid electrolytic capacitor of the present invention is carried out as described above.

Therefore, the lead-out leads of chip-shaped solid electrolytic capacitors are cut extremely short, so the lead-out leads do not bend during handling, and the lead-out leads are not pinched and cut, so the oxide film on the lead-out leads is not damaged. Therefore, it is possible to obtain a product with excellent electrical characteristics with little variation. Since an electroless plating layer is formed on the surface where the notches 2b are formed,
This has remarkable effects such as increasing tanδ and eliminating accidents caused by wire breakage, significantly improving reliability.

Figure 7 shows the results of measuring the leakage current of a chip solid electrolytic capacitor with a rating of 6.3V and 68μF, and comparing it with the conventional method of cutting the lead-out lead 2 by lowering the cutting teeth 5 as shown in Figure 3. .

As is clear from the figure, it was demonstrated that the chip-shaped solid electrolytic capacitor produced by the method of the present invention has significantly improved leakage current value and its variation.

In addition, in the above embodiment, the shape of the notch is V
The shape is not limited to a letter shape, but may be appropriately selected such as a wave shape or a concave shape, and the positions of the notches may also be formed from both the upper and lower sides of the lead-out lead 2.

As described above, the method for manufacturing a chip-shaped solid electrolytic capacitor of the present invention can produce a capacitor that is small, easy to manufacture, has low leakage current, and has little variation, and has extremely high industrial and practical value. It is what it is.

[Brief explanation of the drawing]

Figure 1 is a front view of the main parts of a chip-shaped solid electrolytic capacitor connected to a power supply bar during the manufacturing process, Figures 2 and 3 are explanatory diagrams of cutting the lead-out lead of a conventional chip-shaped solid electrolytic capacitor, and Figure 4 6 to 6 show an embodiment of the chip-shaped solid electrolytic capacitor according to the present invention, FIG. 4 is a sectional view of the main part during the manufacturing process, and FIG.
The figure is an explanatory diagram of the process of forming a notch in the lead-out lead, Figure 6 is an explanatory diagram of the process of cutting the lead-out lead from the notch, and Figure 7 is a diagram of a chip-shaped solid electrolytic capacitor comparing the method of the present invention and the conventional method. It is a leakage current distribution diagram. 1: power supply bar, 2: lead-out lead, 2b: notch, 6: anode body, 7: dielectric oxide film, 8: solid electrolyte layer, 9: cathode conductive layer.

Claims (1)

[Claims] 1. Lead-out leads drawn out from an anode body made of a valve metal are welded to a power supply bar and arranged in a line, and a dielectric oxide film, a solid electrolyte layer, a cathode conductive layer, etc. are formed on the surface of the anode body. At the same time, a conductive material is applied to the anode side of the lead-out lead and cured to form a conductive layer, and then a notch is made in the face parallel to the plane of the power supply bar of the lead-out lead. A plating process is performed to form an electroless plating layer on the conductive layer and the lead-out lead and in the notch, and then a solder layer is formed by contacting with molten solder, and after aging treatment, the lead-out lead is bent and cut from the notch. A method for manufacturing a chip-shaped solid electrolytic capacitor characterized by separating it from a power supply bar. 2. The method for manufacturing a chip-shaped solid electrolytic capacitor according to claim 1, wherein the notch provided on the lead-out lead is in a range of 15 to 90% of the cross-sectional area of the lead-out lead.