JPS6122617A - Method of producing solid electrolytic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing a capacitor formed by laminating valve metals such as aluminum (AI) and tantalum (Ta), an anodized film, a semiconductor layer, and a conductor layer. In particular, the present invention relates to a method for controlling the apparent resistivity of a semiconductor layer formed of an oxide semiconductor or an organic semiconductor.

It is generally believed that the smaller the tan δ or equivalent series resistance (hereinafter referred to as ESR) of a capacitor, the better. However, the oscillation prevention circuit of an audio power amplifier is generally constructed by connecting a capacitor and a resistor in series, and if it were possible to freely select and use a capacitor with an appropriate ESR, the circuit could be improved. It is possible to configure the circuit using only capacitors, which is extremely advantageous in terms of circuit configuration.

In response to such requirements, the ESR of solid electrolytic capacitors depends on the resistance structure of the semiconductor layer, and conventional manufacturing methods
It is difficult to control SH. Therefore, there is a demand for a manufacturing method that can freely control the ESR of solid electrolytic capacitors.

[Conventional technology]

The figure is a side sectional view that does not show an example of a solid electrolytic capacitor.

The anode body 1 is a porous sintered body made by compression molding tantalum or aluminum powder and sintered in a vacuum, that is, a pellet, and after covering its surface with an anodic oxide film, the surface of the pellet is A cathode body 2 is formed by filling and coating every corner of the container with a semiconductor layer such as manganese dioxide (Mn02).

Then, the anode lead 3 is pulled out from the anode body 1, and the cathode body 2
is connected to a cathode lead 6 via a colloidal carbon layer 4 and a silver paint layer 5, and the whole is covered with an epoxy resin or the like 7.

Manganese dioxide (manganese dioxide) in such solid electrolytic capacitors (
The Mn02) layer is usually formed by immersing a sintered body whose surface is covered with an anodic oxide film in an aqueous solution of manganese nitrate, then placing it in an electric furnace and thermally decomposing it at a temperature of around 350°C. .

However, strictly defined, the formed semiconductor layer is MnO2
It is known that the specific resistance of the semiconductor layer changes depending on the amount of oxygen or its degree of porosity.

[Problem that the invention seeks to solve]

It is known that the specific resistance of a semiconductor layer changes depending on the amount of oxygen or its degree of porosity, and methods to control this include controlling the heating conditions, controlling the atmosphere, and equalizing the surface condition of the sintered body. Control from various angles has been suggested, but they all have poor reproducibility (conventional techniques have the problem of not being able to provide sufficient control).

Similarly, the types of materials that can be used for organic semiconductors are limited, and each material exhibits a unique resistance value, and no technology has been established to control the specific resistance.

[Means for solving problems]

The above problems are solved by the method of manufacturing a solid electrolytic capacitor according to the present invention, which controls the equivalent series resistance of the capacitor by adding an insulator to the semiconductor layer.

[Effect]

By adding an insulator to the semiconductor layer and changing the type and addition ratio of the insulator, it becomes possible to freely change the apparent resistivity of the semiconductor layer. That is, various ESR
It is possible to manufacture a capacitor having a

〔Example〕

An embodiment of the method for manufacturing a solid electrolytic capacitor according to the present invention will now be described.

b) Form an aluminum sintered body with a surface area of 150 mm2 joined to the anode lead wire, and use anodization to form a sintered aluminum body with a surface area of 0.2 μ
Form an F element.

1) A silicone resin is added to an aqueous solution of manganese nitrate having a specific gravity of 1.8, and the element is immersed in this mixed solution while stirring and pulled up.

c) Leave at 350°C for 10 minutes to form a mixture of manganese dioxide and silicone resin.

2) Apply colloidal carbon to the surface and bake at 200℃.

e) Apply silver paint on the colloidal carbon, 1
Bake at 50℃.

f) Solder the cathode lead wire to the silver paint.

g) The entire capacitor is covered with epoxy resin to form a solid electrolytic capacitor.

We prepared various mixtures with different ratios of silicone resin added to the manganese nitrate aqueous solution and measured the ESR of the capacitors manufactured by the above method.The relationship between ESR and the ratio of silicone resin added is shown in the table below. .

As shown in the table above, the ESR changes depending on the resin addition ratio. Note that the equivalent capacitance is in the range of 0.15 to 0.25 μF, and no correlation with the resin addition ratio is observed.

Further, in this embodiment, silicone resin is added as an insulator, but the same effect can be obtained by adding powder obtained by crushing silicon dioxide (Si02) or crushed pieces of glass fiber.

By adding an insulator to the semiconductor layer and changing the type and ratio of the added insulator, various ESR characteristics can be achieved.
A solid electrolytic capacitor having the following properties can be manufactured.

That is, it is possible to provide a method for manufacturing a solid electrolytic capacitor in which ESR can be freely controlled.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a method for manufacturing a solid electrolytic capacitor in which ESR can be freely controlled.

[Brief explanation of the drawing]

The figure is a side sectional view showing an example of a solid electrolytic capacitor.

Claims (1)

[Scope of Claims] A capacitor formed by laminating a valve metal, an anodized film, a semiconductor layer, and a conductor layer, characterized in that the equivalent series resistance of the capacitor is controlled by adding an insulator to the semiconductor layer. A method for manufacturing solid electrolytic capacitors.