JPH02303016A - Capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase the capacitance of a capacitor significantly and to enable the capacitor to possess superior frequency-characteristics by a method wherein an organic solid electrolyte introduced in small holes in an insulating film and an organic solid electrolyte formed on the insulating film are respectively used as a cathode conductive layer. CONSTITUTION:The surface of an Al plate having pits of a mean pit diameter of 1.4mum is oxidized, a substrate with an insulating film consisting of Al2O3 formed on it is brought into contact to the Al plate, a TCNQ complex is deposited on this insulating film as an organic substance and this TCNQ complex is formed into a solid electrolyte. In this deposition, a porous conductor 2 covered with an insulating film and a deposition substance, which is housed in a deposition source 4 and becomes an organic solid state electrolyte, are arranged in opposition to each other, the conductor 2 comes into contact to a vibrator 3 and the deposition substance is deposited on the conductor 2 while the conductor 2 is vibrated by a drive power supply 6. Moreover, the interior of a container 1 is evacuated to a vacuum state by a discharging means 5. In such a way, the deposition substance is deposited on an insulating substrate while the insulating substrate is vibrated and a capacitor is manufactured. Thereby, the capacitance of the capacitor can be increased by several times or more compared to a conventional capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to capacitors, particularly solid electrolytic capacitors and methods of manufacturing the same.

(Prior Art) Electrolytic capacitors are widely used in electronic 8i devices and power electronics equipment, but aluminum electrolytic capacitors are the main type. In the case of this aluminum electrolytic capacitor, the anodic oxide film formed on the aluminum surface is the dielectric. The electrolytic solution that comes into contact with this is preferably one that uses ethylene glycol as a solvent and an organic carboxylate as a solvent.Generally, the performance required for an electrolytic solution is that the electrolyte has high electrical conductivity and no defects in the oxide film. It is the ability to recover.

However, in such an electrolytic solution, electrical conduction is based on ionic conduction, which has poor characteristics in a high frequency range and also has problems with temperature characteristics. In order to overcome these drawbacks, various organic materials with electronic conductivity have been developed as solid electrolytes.

These solid electrolytes include charge transfer complexes and conductive polymers. All of these have high electrical conductivity.

In particular, a tetrasiazuki/dimethane (TCNQ) complex is used as a solid electrolyte for aluminum electrolytic capacitors.

(The problem that the invention seeks to solve) Usually! The aluminum oxide film for dehydrator capacitors has small holes with a diameter of several microns in order to increase the capacity. Since the electrolyte solution that has been used for a long time is a liquid, it was able to enter this small hole and effectively increase the capacity.

On the other hand, ever since organic materials have attracted attention as solid electrolytes, methods for forming an organic material layer on the oxide film having small pores have been studied. and (3) vapor deposition method.

It has become clear that method (1) has a fatal weakness in that the TCNQ complex often precipitates as crystals and cannot be effectively incorporated into the small pores. Method (2) can be taken into small pores to some extent and has been put into practical use in some cases, but the range of organic substances that can be used, such as T CN Q n-isomers, is limited because it requires heating. Moreover, the procedure is complicated, and the introduction of various defects, impurities, etc. during the process often causes variations in the performance of the obtained product. Method (3) is easy to operate and can be applied to a variety of organic substances, but it is difficult to introduce organic substances into the pores, making it difficult to increase the capacity.

(Means for solving the problem) As a result of intensive studies to solve the difficulties of each method as described above, we found that by devising the vapor deposition method (3) in particular, it is possible to bring organic substances into the small pores to a certain extent. However, they established a method to form an organic layer and developed a capacitor with large capacity and good frequency characteristics.

That is, the present invention relates to a capacitor and its illuminating method, which is characterized in that an organic material that becomes a solid electrolyte is deposited on an insulating film having minute pores while vibrating it and used as a cathode conductive layer. Upstream capacitance increases significantly and frequency characteristics are also improved.

An example of an apparatus for carrying out the present invention is shown in FIG. 1 below.

In a container 1, a porous conductor 2 covered with an insulating film and a vapor deposition material that will become an organic solid electrolyte housed in a vaporized N source 4 are arranged facing each other, and the porous conductor 2 is in contact with a vibrating body 3. It can be vibrated using the drive power source 6. While the porous conductor 2 is vibrating, the deposition substance is deposited on the porous conductor 2.

In normal vacuum evaporation, the container 1 is moved up to the exhaust means 5 and evacuated, but a high vacuum is not necessarily required and the evaporation can be carried out at a low pressure or at atmospheric pressure. Further, the vapor deposition substance is usually evaporated by heating the heater of the vapor deposition source 4, but various heating methods such as electron beam heating, laser heating, etc. can be used. Furthermore, although various methods are possible (not shown here), such as applying a charge to the evaporation material during the evaporation process and accelerating it by an electric field, or performing evaporation in a cluster form, the present invention is applicable to the insulating material that is the evaporation substrate. Its unique feature is that capacitors are manufactured by vapor deposition while vibrating the substrate, and it can be applied to all normal vapor deposition methods. Of course, the method of applying vibration, the method of holding the insulating film that is the vapor deposition substrate, the method of facing the substrate, etc. are not limited to any particular method, but include audio frequency, ultrasonic frequency, 1 to 10
'Hz is often used.

The basic structure of the capacitor manufactured by the method of the present invention is an insulating film on a porous anode conductor, an organic cathode conductive layer formed on top of the insulating film while vibrating, and a cathode conductor layered on top of that. A third layer may be provided between the cathode conductive layer and the cathode conductor.

(Examples) The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Dog 1" [L Barium titanate (B a T i O3) based ultrasonic transducer (manufactured by Murata Manufacturing Co., Ltd.; diameter 50 mφ, thickness 4 mtms, resonance frequency 45.45 KHz) with an average pit diameter of 1.4
A substrate on which an insulating film (thickness 14A) of A I 20 z was formed by oxidizing the surface of an aluminum plate of μ theory was brought into contact with the
A TCNQ complex (EO8II) was deposited thereon as an organic material. This TCNQ complex becomes a solid electrolyte.

During this vapor deposition, four ultrasonic vibrators are activated by a driving power source.
Excitation was performed at 5 KHz, and 0.03-0.06 g of TCNQ complex was evaporated under vibration conditions. A capacitor was formed by coating this with silver paste as a cathode, and the capacitance was measured to be 450 nF/C at an applied voltage of 25 V.

For comparison, a capacitance of 80 nF/am2 was obtained when vapor deposition was performed under exactly the same conditions without applying vibration. It can be seen that by applying vibration to the substrate, the capacitance increases by more than 5.6 times.

In addition, the tan δ of both pit diameter capacitors is 1.6~
It was 3.4.

The results of measuring the frequency characteristics of this capacitor between 10' and 10'Hz are shown in FIG. 2 by black circles. It can be seen that the characteristics are better up to extremely high frequencies compared to the characteristics of ordinary electrolyte type capacitors (white circles).

Example 2 The substrate was vibrated under the same conditions as Example 1, except that the pit diameter was changed to 2.6μ, but when the same amount of the same TCNQ rust body was deposited, the result was 560nF/c at an applied voltage of 25V.
A capacity of m2 was obtained. It can be seen that the value is seven times higher than the value when vapor deposition is performed without applying vibration.

Example 3 N-n-butylisoquinolinium TC as an organic substance
When the NQ complex was deposited under the same conditions as in Example 1 while vibrating the substrate and a capacitor was fabricated by the same method, a capacitance of 3SOnF/cm2 was obtained. This was approximately 3.4 times as high as when no vibration was applied.

(Effects of the invention) As can be seen from the above explanation, it is very effective to create a capacitor by depositing an organic substance while vibrating the substrate and using it as a cathode conductive layer, and the capacitance of the capacitor is This is several times higher than without it, and the frequency characteristics are also extremely excellent.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of an apparatus for implementing the present invention, and FIG. 2 is a diagram showing frequency characteristics of a capacitor of the present invention and a capacitor manufactured for comparison. 1. Container 2. Porous conductor 3. Vibrating body 4. Evaporation source patent applicant Katsumi Yoshino Patent applicant Nippon Carlit Co., Ltd. Figure 1

Claims (1)

[Scope of Claims] 1. A solid electrolytic capacitor characterized in that an organic solid electrolyte introduced into the pores of an insulating film and an organic solid electrolyte formed on the insulating film serve as a cathode conductive layer. 2. The solid electrolytic capacitor according to claim 1, wherein the insulating film is aluminum oxide or tantalum oxide. 3. The solid electrolytic capacitor according to claim 1 or 2, wherein the organic solid electrolyte is a tetracyanoquinodimethane complex. 4. A method for producing a solid electrolytic capacitor, which comprises depositing an organic solid electrolyte on an insulating film while vibrating it to form a cathode conductive layer. 5. The method for manufacturing a solid electrolytic capacitor according to claim 4, wherein the insulating film is aluminum oxide or tantalum oxide. 6. The method for producing a solid electrolytic capacitor according to claim 4 or 5, wherein the organic solid electrolyte is a tetracyanoquinodimethane complex. 7. The method for manufacturing a solid electrolytic capacitor according to claim 4, wherein the insulating film is vibrated by ultrasonic waves.