JP2741064B2 - Manufacturing method of solid capacitor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a solid capacitor using a thin film as a dielectric film by a Langmuir-Blodgett method.

(Prior Art) In recent years, with the progress of electronic devices, there has been an increasing demand for miniaturization of electronic components used therein, and in the field of solid capacitors, dielectric layers and solid electrolyte layers have been made thinner.

As one example, a solid capacitor in which a thin film (hereinafter abbreviated as an LB film) formed by a Langmuir-Blodgett method is laminated on an electrode has been proposed (JP-A-63-80514). This capacitor uses a dielectric layer formed of an LB film, so that the thickness of the dielectric can be made extremely thin, and has a film structure in which monomolecular films in which molecules are regularly arranged on an electrode plate are accumulated. Therefore, a solid capacitor excellent in pinhole-free, high withstand voltage, and excellent in insulation performance can be obtained.

Incidentally, as a method for laminating an LB film on an electrode in manufacturing a solid capacitor, a method disclosed in Japanese Patent Application Laid-Open No. 63-122207 is known. In this method, a solid electrolyte LB film is laminated on an electrode. However, the method can be similarly used for laminating a dielectric LB film on an electrode.

This method will be described with reference to FIG. 3. A monomolecular film (not shown) of a film material is formed on a water surface in a Langmuir-Blodget device (hereinafter abbreviated as an LB device) 8 and a plastic film is formed by a pulley 9. The LB film is accumulated on the electrode plate by continuously moving the electrode plate on which the aluminum thin film and aluminum oxide thin film are laminated on the substrate up and down, and at the same time, continuously bringing the floats 11 and 12 closer to the electrode plate direction. It is to be laminated.

(Problems to be Solved by the Invention) The above-described method for manufacturing a solid capacitor in which an LB film is laminated on an electrode plate can form a pinhole-free film having a small thickness. However, the use of floats was necessary for controlling the surface pressure, and a complicated LB apparatus had to be used. Further, in the above method, two LB film laminated electrode plates could not be obtained at the same time by one LB apparatus.

The object of the present invention is to eliminate the above disadvantages, use an LB device having a simpler structure than in the past, and simultaneously stack LB films on two electrode plates with one LB device, and then stack the two plates. An object of the present invention is to provide a method for easily manufacturing a flat plate capacitor or a wound wound capacitor.

(Means for Solving the Problems) The present invention has been made to solve such problems. In the production of a solid capacitor having a dielectric film on an electrode plate, two electrode plates are formed by a dielectric material. Expanded material
The dielectric LB film is laminated by facing the inside of the trough of the LB device, simultaneously raising and lowering the two electrode plates continuously and vertically, and simultaneously moving the two electrode plates so as to approach the horizontal direction continuously. Characterized by using the electrode plate as a constituent member of a solid capacitor, and using a method simpler than the conventional method, having a small size, a small leakage current, a large capacity, and a high withstand voltage. Is made possible.

The method of the present invention will be described with reference to the drawings. FIGS. 1 and 2 show conceptual diagrams of a method of laminating an LB film on an electrode, where 1 indicates an LB device, and 2 and 3 are opposed to each other. Two electrode plates. Numerals 4 and 4 'are vector representations of the vertical lifting or lowering speed Y of the electrode plates, and the two electrode plates 2 and 3 are continuously raised or lowered in the vertical direction at the same speed. It shows that. 5 and 5 'are vector representations of the speed X of the approach of the electrode plate in the horizontal direction which is performed in parallel with the raising and lowering of the electrode plate in the vertical direction. It indicates that they approach in the same direction at the same speed. Therefore, the two electrode plates continuously move in the a direction or the b direction while facing each other. The lower part of FIGS. 1 and 2 conceptually shows the state of accumulation of the monomolecular films 6, 6 ', 7, 7' on the electrode plate when the electrode plate is moved.

Various methods can be adopted as a method of laminating the LB film on the electrode plate. As shown in FIG. 1, a method in which opposing electrode plates are successively pulled up in a direction and accumulated while approaching as shown in FIG. 1, or as shown in FIG. Then, a method of accumulating by approaching while continuously pulling up, or a method of repeating these laminating operations a plurality of times may be mentioned, but the present invention is not limited to these methods.

The LB device used in the present invention may have various structures. For example, making the width of the electrode plate smaller than the width of the trough, making the width of the electrode plate the same as the width of the trough, moving on the trough, applying zone heating to the monomolecular film on the water surface to change it to a multilayer film For example, a device provided with a zone heater capable of performing the above-described operation may be used.

Further, the method of the present invention can be carried out by variously changing the method of laminating the LB film on the electrode plate according to the type of the dielectric material used.

For example, (1) a method in which a polymer precursor is developed on a water surface and accumulated on an electrode plate, and then heat-treated or chemically treated to change the precursor on the electrode plate into a polymer; (3) a method in which the monomers are spread on the water surface and accumulated on the electrode plate, and then polymerized on the electrode plate; and (4) a monomer is accumulated on the water surface. And then accumulating on the electrode plate after (5) developing the low molecular weight compound on the water surface and then accumulating on the electrode plate. Further, as one mode of the method (1), after accumulating the polymer precursor on the electrode, heating is performed in a state where the obtained two LB film accumulation electrodes are combined (see FIGS. 1 and 2). A method of changing a body film into a polymer film can also be performed.

Examples of the dielectric material used in the method (1) include a polyamic acid alkylamine salt and a polyamic acid long-chain alkyl ester. After these precursor substances are accumulated on the electrode plate, the former is treated by chemical treatment, the latter is, for example, 200
Converted to polyimide by heat treatment at ~ 400 ° C.

Examples of the dielectric material used in the method (2) include amphiphilic polyamide, polyimide, polycarbonate, polyester, and polyether sulfone.

Examples of the dielectric material used in the methods (3) and (4) include higher fatty acid vinyl. Specific examples thereof include vinyl stearate, vinyl palmitate, vinyl arachiate and the like.

As the dielectric material used in the method (5), higher fatty acids can be mentioned. Specific examples thereof include stearic acid, arachidic acid, palmitic acid, heptadecylic acid, nonadecanoic acid,
Hene eicosanoic acid.

As described above, in the present invention, since the dielectric formed of the LB film is used, the thickness of the dielectric can be extremely reduced. Its thickness varies somewhat depending on the dielectric material used, but can vary from a few microns to a few microns. If necessary, the same type or different types of dielectric films can be laminated by another method, for example, a coating method, after laminating an extremely thin LB film.

As the electrode plate used in the present invention, a material such as aluminum, tantalum, copper, zinc, tin, nickel, and stainless steel is used, and a foil shape is particularly preferable. Instead of the metal foil electrode, a material obtained by laminating an electrode material as a thin film on a base material such as metal or plastic by means of vacuum deposition, sputtering, ion plating or the like may be used.

The electrode plate on which the dielectric LB film produced by the method of the present invention is laminated can be used to produce a flat plate capacitor by laminating two electrode plates obtained as shown in FIGS. it can. Further, the method of the present invention is applied to both sides of the electrode, and an electrode plate having an LB film laminated on both sides is overlapped and wound, whereby a wound capacitor can be manufactured.

(Examples) Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to only these Examples.

Example 1 A polyamic acid alkylamine salt (a precursor of polyimine) having a repeating unit represented by the following formula was used as a dielectric material.

The precursor was spread on the water surface in the trough of the LB apparatus using a solvent, and after evaporating the solvent, the operation of FIG. 1 was repeated to accumulate the LB film on the aluminum foil. Then this LB
The membrane was treated with acetic anhydride and pyridine in the presence of a benzene medium to obtain an electrode plate on which a polyimine membrane having a repeating unit represented by the following formula was laminated.

105v / cm because this polyimine film has very few defects
It has the above dielectric breakdown strength and a resistivity of 10 ¹⁵ Ω · cm. The two electrode plates thus obtained were overlapped to prepare a flat capacitor.

Example 2 Polyamic acid long-chain alkyl ester having a repeating unit represented by the following formula as a dielectric material (a precursor of polyimine)
It was used.

The precursor was spread on the water surface in the trough of the LB apparatus using a solvent, and after the solvent was evaporated, the operation shown in FIG. 2 was repeated to accumulate the LB film of the precursor on the aluminum foil. Then, the precursor LB film laminated electrode was heated at about 250 ° C. to obtain an electrode plate on which a polyimine film having the same repeating unit as in Example 1 was laminated. The dielectric breakdown strength and resistivity of this film were almost equal to those of Example 1. The two electrode plates thus obtained were overlapped to prepare a flat capacitor.

In this example, when two electrode plates on which the precursor was laminated were stacked and heat-treated in the same manner, the same results were obtained as in the case where the electrode plates were heat-treated one by one.

Example 3 Stearic acid was used as a dielectric material. Stearic acid was dissolved in benzene and spread on the water surface in the trough of the LB device. After the volatilization of benzene, the monomolecular film formed on the water surface was subjected to the operation method shown in FIG. 1 to repeat the stearic acid LB film on the aluminum foil. The thus obtained electrode plates were overlapped to prepare a plate capacitor.

Example 4 Arachiic acid was used as a dielectric material. Arachiic acid was dissolved in benzene and spread on the water surface in the trough of the LB device. After the volatilization of benzene, the arachidic acid LB film was accumulated on the aluminum foil by repeating the operation method shown in FIG. 1 for the arachidic acid monomolecular film formed on the water surface. Next, the direction of the electrode was reversed, and an LB film of arachidic acid was also accumulated on the back surface. The two electrode plates thus obtained were wound to form a wound capacitor.

Example 5 An amphiphilic polyamine was used as a dielectric material.
A small amount of polyamine was dissolved in a solvent and developed in a trough of an LB apparatus. After the evaporation of the solvent, the polyamine monomolecular film formed on the water surface was accumulated on the aluminum foil according to the operation method shown in FIG.

The thus obtained electrode plates were overlapped to prepare a plate capacitor.

(Effects of the Invention) As described in detail above, according to the method of the present invention, two LB film laminated electrode plates can be manufactured at one time, and by combining these two electrode plates, a flat plate capacitor can be manufactured. In addition, since a wound capacitor can be easily manufactured, the production process can be simplified.

Further, the LB apparatus used in the present invention does not require the float used in the conventional apparatus, so that the manufacturing apparatus can be simplified.

In addition, since the LB film is used, it is possible to manufacture a small and lightweight capacitor having a large capacity, a low leakage current, a high withstand voltage, and a high insulation performance.

Therefore, the present invention achieves extremely excellent effects in terms of the production process, equipment, and performance of the capacitor.

[Brief description of the drawings]

FIGS. 1 and 2 are conceptual diagrams showing a process of laminating a dielectric LB film on an electrode plate according to the method of the present invention. The lower part of each figure shows a state in which the LB film is accumulated on the electrode in each process. It shows. FIG. 3 shows the LB in the conventional method of accumulating the LB film on the electrode plate.
FIG. 2 shows a conceptual diagram of the device. 1, 8: LB device 2, 3, 10: Electrode plate 4, 4 ': Speed vector indicating the vertical lifting or lowering speed of the electrode plate 5, 5': Horizontal approach speed of the electrode plate 6, 6 ', 7, 7' ... monomolecular film 9 ... pulleys 11, 12 ... floats a, b ... moving direction of electrode plate

Claims (5)

(57) [Claims] In the manufacture of a solid capacitor having a dielectric film on an electrode plate, two electrode plates are opposed to each other in a trough of a Langmuir-Blodget apparatus in which a dielectric material is developed. An electrode plate with a Langmuir-Blodgett film laminated thereon is obtained by simultaneously raising and lowering the plate continuously in the vertical direction, and simultaneously moving the plate so as to approach the horizontal direction. A method for manufacturing a solid capacitor, which is used as a member. 2. The method according to claim 1, wherein the vertical lifting and the horizontal movement of the electrode plate are simultaneously and continuously performed in one lamination operation.
3. The method for manufacturing a solid capacitor according to item 1. 3. The method for manufacturing a solid capacitor according to claim 1, wherein in a single laminating operation, the lifting and the horizontal movement of the electrode plate are simultaneously performed continuously in the vertical direction. 4. The method for manufacturing a solid capacitor according to claim 1, wherein the laminating operation is repeated a plurality of times. 5. The method according to claim 1, wherein a polyamide precursor is used as a dielectric material, and after the precursor is accumulated on the electrode plate, the precursor film is converted into a polyamide film by heat treatment or chemical treatment. A method for manufacturing a solid capacitor according to any one of the above.