JPH1116783A - Manufacture of conductive high-molecular solid-state electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use conductive high molecular compound, which is kept low in viscosity so as to improve pores inside an anode in permeability to the molecular compound by a method, wherein organic semiconductor mother liquid which is not subjected to polymerization reaction yet and where a specific amount of acrylic resin is dissolved is used. SOLUTION: An anode lead leading wire 2 of Ta is implanted upright in tantalum powder, the tantalum powder is subjected to pressure molding, the molded tantalum body is sintered into an anode body 1. Then, the anode lead wire 2 is welded into a belt-like metal plate 3, and an oxide film 4 is formed on the surface of the anode body 1. Thereafter, about 0.1 to about 5 wt.% acrylic resin is dissolved into a pyrrole monomer water solution to form organic semiconductor mother liquid, the anode body 1 is dipped into the organic semiconductor mother liquid, and a chemical polymerization reaction takes place to form an organic semiconductor layer 5 which contains an acrylic resin component. Thereafter, a conductor layer 9 is formed by the use of Ag paste to serve as a cathode layer for the formation of a capacitor device. By this setup, an organic semiconductor layer is formed, even into pores inside an anode to improved the covering rate.

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 conductive polymer solid electrolytic capacitor, and more particularly to a method for manufacturing a conductive polymer solid electrolytic capacitor obtained by adding an acrylic resin or a cellulose resin as a binder to a semiconductor mother liquor. About.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 60-206127 discloses a method and a technique for producing a solid electrolytic capacitor having a small tan δ and good high-frequency characteristics using an organic semiconductor containing an acrylic resin as a binder as a solid electrolyte. Have been.

[0003] As shown in FIG. 8, a conventional conductive polymer solid electrolytic capacitor is formed by erecting an anode lead wire 2 on a valve metal powder, press-molding it, and sintering it in a high vacuum. Then, the anode lead wire 2 was welded to the strip-shaped metal plate 3 to form an oxide film 4 which is a dielectric substance on the surface of the anode body 1 and then mixed with an organic semiconductor and an acrylic resin. The organic semiconductor layer 7 is injected into the inside of the anode body 1, and thereafter, the conductor layer 9 is formed to complete the capacitor element. Next, the capacitor is completed by connecting to the lead terminal 2 and covering with a resin.

[0004]

When an organic semiconductor according to the prior art is formed by injecting an organic semiconductor into the anode body after adding a binder such as an acrylic resin to the organic semiconductor of the prior art, the viscosity of the organic semiconductor is high. However, there is a disadvantage that the permeability to the pores is deteriorated and the coverage is reduced. In addition, due to a decrease in the coverage, the conductor layer comes into contact with the dielectric film due to mechanical stress or thermal stress during mounting, thereby causing a short circuit failure.

[0005] It is an object of the present invention to be able to withstand heat history during mounting.

[0006]

The conductive polymer solid electrolytic capacitor of the present invention uses an organic semiconductor mother liquor before polymerization reaction in which an acrylic resin is dissolved, and therefore has a higher viscosity than that obtained by mixing an organic semiconductor with an acrylic resin. Can be lower. After the anode body is immersed in the organic semiconductor matrix before the polymerization reaction, the polymerization reaction is performed to form an organic semiconductor layer.
It has an organic semiconductor layer that can withstand mechanical stress capable of improving the coverage of the organic semiconductor layer and thermal stress during mounting.

According to the present invention, an organic semiconductor layer can be formed in the pores inside the anode body, and an increase in leakage current due to mechanical stress during assembly and thermal stress during packaging or mounting can be prevented. Short defects can be reduced.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view of a solid electrolytic capacitor according to the manufacturing method of the first embodiment of the present invention, and FIG. 2 is a process flowchart of the method of manufacturing the solid electrolytic capacitor of the first embodiment of the present invention. . As shown in FIGS. 1 and 2, a method for manufacturing a solid electrolytic capacitor according to a first embodiment of the present invention is as follows. The anode body 1 was sintered in the anode, and then the anode lead wire 2
Is welded to the strip-shaped metal plate 3 to form an oxide film 4 as a dielectric layer on the surface of the anode body 1 electrochemically, and then an acrylic resin is dissolved at a ratio of 1 wt% to an aqueous solution containing pyrrole as a monomer. After being immersed in the organic semiconductor mother liquor, a chemical polymerization reaction is performed to form an organic semiconductor layer 5 containing an acrylic resin component.
Is formed to complete the capacitor element.

Next, the lead terminals are connected and packaged with resin to complete the capacitor.

FIG. 3 shows the relationship between the amount of acrylic resin added, the coverage of the organic semiconductor layer covering the oxide film, and the thickness of the organic semiconductor layer outside the anode body. FIG. 4 shows the amount of acrylic resin added and the solder heat resistance. The relationship of the leakage current by a test is shown. 3 and FIG. 4, when the addition amount of the acrylic resin is 0 wt%, the thickness of the organic semiconductor layer is thin, so that the occurrence of a leakage current defect due to the solder heat resistance test is recognized. When the addition amount of the acrylic resin is 10 wt%, Since the coverage of the organic semiconductor layer is poor, occurrence of a leakage current defect in the solder heat resistance test is recognized, and it can be determined that the leakage current characteristic of the capacitor is adversely affected. Furthermore, if the addition amount of the acrylic resin is in the range of 0.1 wt% to 5 wt%, the leakage current characteristics can be improved,
Considering the appearance rate of the capacity and the variation at the time of preparing the organic semiconductor mother liquor, it is determined that the addition amount of the acrylic resin is preferably about 1.0 wt%.

The above-described prototype according to the present invention and the conventional product shown in FIG. 8 were compared in terms of the organic semiconductor layer coverage and film thickness. The results are shown in FIG. 5 (A). The coverage of the organic semiconductor layer according to the first embodiment is shown in FIG. 5 (A). FIG. 5 (B) shows a conventional organic semiconductor mixed with 1.0 wt% of acrylic resin and then injected into the anode body. 4 shows the coverage of the organic semiconductor layer when the organic semiconductor layer was formed by the method described above. From this figure, it was found that the coverage of the organic semiconductor layer of the first embodiment can be improved by about 30% as compared with the conventional product.

FIG. 6A shows the thickness of the organic semiconductor layer according to the first embodiment of the present invention, and FIG. 6B shows a conventional organic semiconductor mixed with 1.0% by weight of an acrylic resin and then an anode. This shows the thickness of the organic semiconductor layer when the organic semiconductor layer is formed by injecting it into a body. From this figure, the film thickness of the organic semiconductor layer of the first embodiment is equivalent to that of the conventional product.
Further, the prototype according to the present invention and the conventional product shown in FIG.
The change of the leakage current value by the test of immersion for 2 seconds was compared.
The results are shown in Table 1 (A), the short-circuit failure rate during the manufacturing process according to the first embodiment, and Table 1 (B), a conventional organic semiconductor mixed with 1.0 wt% of acrylic resin. The percentage of short-circuit defects during the manufacturing process when an organic semiconductor layer is formed by injecting the organic semiconductor layer into the anode body is shown below. From this Table 1, it was found that the short-circuit defect rate of the first embodiment was significantly reduced as compared with the conventional product.

[0014]

[Table 1]

FIG. 7A shows a change in the leakage current value in the solder heat resistance test according to the first embodiment, and FIG. 7B shows a conventional organic semiconductor layer 5 made of acrylic resin of 1.0%.
The change of the leakage current value in the solder heat resistance test when the organic semiconductor layer 5 is formed by being injected into the anode body 1 after leaking by wt% is shown. From this figure, it was found that the reliability of the first embodiment was extremely small in the change of the leakage current value as compared with the conventional product.

From the results described above, the conventional organic semiconductor layer in which an acrylic resin was mixed at 1.0 wt% and then injected into the anode body had a good film thickness of the organic semiconductor layer but a poor coverage, so that the leakage current characteristic was poor. However, it is clear that the first embodiment of the present invention is superior to the conventional product.

Another embodiment of the present invention is a capacitor element completed by using a cellulose resin in place of the acrylic resin described in the first embodiment. In the case of the cellulose resin, the same results as in the case of the acrylic resin can be obtained.

[0018]

The first effect is that the coverage of the organic semiconductor layer is improved. The reason is that the anode body is immersed in an organic semiconductor mother liquor in which 0.1 to 5 wt% of an acrylic resin is dissolved, and the organic semiconductor mother liquor penetrates into pores inside the anode body, and then forms an organic semiconductor layer by a polymerization reaction. This is because an organic semiconductor layer can be formed in the pores inside the anode body and the coverage can be improved. As a result, it is possible to prevent an increase in leakage current due to mechanical stress at the time of assembly and thermal stress at the time of packaging and mounting, thereby improving the yield.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a solid electrolytic capacitor manufactured by a manufacturing method according to a first embodiment of the present invention.

FIG. 2 is a process flowchart of a method for manufacturing the solid electrolytic capacitor according to the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the amount of acrylic resin added, the coverage of the organic semiconductor layer covering the oxide film, and the thickness of the organic semiconductor layer outside the anode body.

FIG. 4 is a characteristic diagram showing a relationship between an added amount of an acrylic resin and a leakage current in a solder heat resistance test.

FIGS. 5A and 5B show a case where an organic semiconductor layer is formed by mixing an acrylic resin with an organic semiconductor of 1.0 wt% in the first embodiment of the present invention and a conventional organic semiconductor and then injecting the mixture into an anode body; FIG. 4 is a distribution diagram of the coverage of the organic semiconductor layer of FIG.

FIGS. 6A and 6B show a case where an organic semiconductor layer is formed by mixing 1.0 wt% of an acrylic resin with an organic semiconductor according to the first embodiment of the present invention and a conventional organic semiconductor and then injecting the mixture into an anode body; 3 is a distribution diagram of the film thickness of the organic semiconductor layer of FIG.

FIGS. 7A and 7B show an organic semiconductor layer formed by mixing 1.0% of acrylic resin with a conventional organic semiconductor according to the first embodiment of the present invention and injecting it into an anode body; FIG. 8 is a distribution diagram showing a change in a leakage current value in a solder heat resistance test in the case.

FIG. 8 is a sectional view of a solid electrolytic capacitor manufactured by a conventional manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode body 2 Lead wire of anode lead 3 Strip metal plate 4 Oxide film 5 Organic semiconductor layer containing acrylic resin 6 Organic semiconductor layer containing cellulose resin 7 Conventional organic semiconductor layer containing acrylic resin 8 Inside of anode body 9 Conductor layer

Continuing on the front page (72) Inventor Kenichi Takahashi 560, Irizen-cho, Shimoshinkawa-gun, Toyama Prefecture Inside Toyama NEC Co., Ltd.

Claims (3)

[Claims] 1. An anode lead wire is directly exposed to a fine powder of a valve action metal, and the anode body formed by pressing and sintering in a high vacuum is successively formed with an anodic oxide film, an organic semiconductor layer and a cathode conductor layer. In the method for producing a conductive polymer solid capacitor in which is formed, a resin as a binder is added to the semiconductor mother liquor in the step of forming the semiconductor layer, and the amount added is 0.1 wt.
A method for producing a conductive polymer solid electrolytic capacitor, characterized in that it is formed by a chemical polymerization reaction at a concentration of from 5% to 5% by weight. 2. The method according to claim 1, wherein the resin as the binder is an acrylic resin. 3. The method according to claim 1, wherein the resin as the binder is a cellulosic resin.