KR19990086255A - Manufacturing method of chip type solid electrolytic capacitor - Google Patents

Abstract

The present invention relates to a method of manufacturing a chip-type solid electrolytic capacitor, the manufacturing process of forming a dielectric oxide film layer (5) on the metal foil capable of forming an oxide film, and to protect the oxide film layer during electrolytic polymerization on the dielectric oxide film layer Hazardous electrically conductive polymer (3) having an electrically insulating property and hardness, and a soluble conductive polymer layer formed by solution bonding so that the soluble conductive polymer is dissolved in a solvent and overlaps the dielectric oxide layer used as a cathode and the lower portion of the HF protective insulating layer (6 , The first conductive layer), the highly conductive solid electrolyte layer 7 and the second electrode by electrolytic polymerization by contacting the polymerizing electrode 4 with the soluble conductive polymer layer superimposed on the dielectric oxide film and the upper portion of the chemical protection foil. Conductive layer) and the conductive cathode layers 8 and 9 of the multi-layer structure are formed on the solid electrolyte layer to be connected to the lead frame and to increase the capacity. The anode of the metal foil is characterized by withdrawing a predetermined length, and stacking the purchase been designed and cut to the right or left by the width spacing of the anode foil on one side of the cathode surface.

Description

Manufacturing method of chip type solid electrolytic capacitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a chip-type solid electrolytic capacitor. The present invention relates to a method of manufacturing a chip-shaped solid electrolytic capacitor having a low ESR and low impedance characteristics and surface mount using a highly conductive polymer thin film as an electrolyte. It is about.

In general, the structure of a solid electrolytic capacitor is formed by forming a dielectric oxide film on an electrolytically etched metal foil, winding a wound aluminum foil formed by applying a conductive solid electrolyte layer on top of it, and then wrapping it in a circular aluminum case having an internal terminal. The exterior of the aluminum case is wrapped with resin. At this time, the electrical characteristics of the solid electrolytic capacitor manufactured according to the type and the formation method of the conductive solid electrolyte is also changed.

The solid electrolyte used in the aluminum solid electrolytic capacitor described above can be broadly divided into an inorganic solid electrolyte and an organic solid electrolyte, and the organic solid electrolyte is subdivided into an organic semiconductor type and a polymer electrolyte type. Typical inorganic solid electrolytes include manganese dioxide and lead dioxide. In the case of a solid electrolytic capacitor, a tantalum electrolytic capacitor was developed by impregnating an aqueous solution of manganese nitrate into a tantalum sintered body and using manganese dioxide produced by pyrolysis as a solid electrolyte layer.

In addition, the organic semiconductor is tetracyanoquinone dimethane (TCNQ) complex salt. The solid electrolytic capacitor using TCNQ complex salt has already been developed and commercialized, but TCNQ also has a high conductivity and a poor high frequency characteristic and is formed by thermal melting impregnation, so that it has manufacturing problems and poor thermal stability of TCNQ.

In addition, examples of other organic solid electrolytes include conductive polymer materials such as polyaniline and polypyrrole. Polypyrrole produced by electrolytic oxidation polymerization is known as a conductive polymer having a very high conductivity and excellent thermal stability of 10 ² S / cm or more. It also has excellent thermal stability, which makes it possible to chip the product.

Therefore, a chip-type solid electrolytic capacitor was manufactured and commercialized using an organic solid electrolyte capable of chipping, overcoming the problems of the conventional solid electrolytic capacitor.

In the conventional chip type solid electrolytic capacitor, a metal foil capable of forming a dielectric oxide film is enlarged through electrolytic etching to increase the surface roughness, and then the metal foil is cut using a mold to form a device. A first conductive layer forming an insulator band separating the positive electrode and the negative electrode and forming a conductive polymer layer by manganese dioxide, lead dioxide, or chemical polymerization on only the negative electrode portion, and a second conductive layer by electrolytic polymerization, It produced by the manufacturing method which apply | coats carbon and silver paste which are multilayer conductive cathode materials sequentially.

However, the chip-type solid electrolytic capacitor manufactured by the above-described manufacturing method distinguishes a metal foil capable of forming a dielectric oxide film layer from a cathode for electrically connecting a lead frame and a cathode area to which a conductive polymer material and a conductive cathode material can be sequentially applied. The insulator band forming process for the purpose is to enter between the etching process for enlarging the surface and the chemical conversion process for forming the dielectric layer, resulting in poor work continuity.

In addition, during the formation of the first conductive layer, a process of thermally decomposing or immersing the metal foil having the dielectric oxide film layer formed therein into the monomer and oxidizing the same may be repeated several times. The first electrode formed on the dielectric oxide film layer when the second electrode is formed by electrolytic polymerization is formed. Direct connection to the conductive layer results in very poor leakage current characteristics after fabrication. As a result, the existing process described above has a problem that causes a decrease in overall product yield and a decrease in productivity.

In addition, due to the thickness of the laminated positive electrode foil when the metal foil elements are laminated in order to increase the capacity, there is a problem that a defect occurs during welding.

The present invention forms a dielectric oxide layer on top of the metal foil capable of forming an oxide film, and cut in the shape of a stackable chemical foil to solve the above-described problems, and then insulates the insulating film to protect the oxide film layer during electrolytic polymerization on the coating layer. After the formation, the first conductive layer is formed by a solution impregnation method to the lower portion of the insulating layer. Next, the electrode for polymerization is brought into contact with the upper portion thereof to form a second conductive layer by electrolytic oxidation polymerization, and then a conductive cathode layer having a multilayer structure is formed on the second conductive layer and connected to a lead frame to shorten the production time. The purpose is to improve leakage current characteristics and product yield after device fabrication.

Figures 1a to 1d is a view showing the cutting shape of the metal foil when manufacturing the laminated device according to the present invention.

2a to 2e are cross-sectional views sequentially showing the manufacturing process of the chip-shaped solid electrolytic capacitor according to the present invention.

<Brief description of the main parts of the drawing>

1 anode 2 cathode

3: chemical protection foil insulator 4: polymerization auxiliary electrode

5: dielectric oxide film 6: first conductive layer

7: second conductive layer 8: carbon layer

9 silver paste layer 10 cathode of lead frame

11: anode of lead frame a: anode foil width

12: first layer element in lamination 13: second layer element in lamination

14: third layer element in the lamination 15: fourth layer element in the lamination

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1A to 1D show an embodiment of a chip type electrolytic capacitor according to the present invention, in order to facilitate assembly when a metal foil on which a dielectric oxide film 5 is formed is stacked in parallel with a device in which a cathode material is formed. The formation position of the metal foil in which the anode 1 was formed is shown. First, FIG. 1A shows a metal foil when a device in which a negative electrode material is not stacked is formed so that the positive electrode 1 is positioned at one side of the negative electrode 2 with a predetermined width a. The cutting shape of the metal foil for laminating the formed element is shown, and it is shown that it was formed in the cathode 2 so that the anode 1 of FIG. 1A may have a constant width a inside as much as the width a formed, and FIG. It is a cutting shape of a metal foil for stacking elements formed with two cathode materials, and is formed inside 2a from the position of the first anode 1 of FIG. 1A to have a constant width (a), and FIG. 1D is an element having three cathode materials formed thereon. It shows the cutting shape of the metal foil for laminating the anode 1 is formed in the inside 3a than the anode 1 of Fig. 1a. At this time, the width of the laminated element on which the negative electrode material is formed is manufactured to be the same as the width of the positive electrode 1, and the stacked elements are attached by a conductive adhesive. In addition, anode foils having different positions of the same width are electrically connected to the anode frame by using spot welding, ultrasonic welding, laser welding, and stitch processes.

Next, FIGS. 2A to 2E are cross-sectional views sequentially illustrating a manufacturing process of a chip type electrolytic capacitor according to the present invention. First, FIG. 2A is a dielectric oxide film 5 formed on a metal foil on which an oxide film can be formed. As shown in FIGS. 1A to 1D, the cut sheet is cut into a shape of a chemically feasible foil, and FIG. 2B has electrical insulation and hardness for protecting the oxide film 5 during electrolytic polymerization on the dielectric oxide film 5. The upper portion of the metal foil cathode (2), which is an element of the solid electrolytic capacitor, is formed on both surfaces with the upper portion of the metal foil cathode insulator (3) not overlapping with the portion where the ultra-thin anode (1) is welded with the lead frame. In addition, it shows what was formed to the side surface of the area where the chemical protection foil insulator 3 was formed. At this time, an epoxy resin, a fluororesin, an acrylic resin, or the like is used as a material for forming the chemical protection foil insulator 3. Next, FIG. 2C shows the soluble conductive polymer layer 6 or less by solution impregnation so as to dissolve the soluble conductive polymer in a solvent and overlap the entire dielectric oxide film 5 having the area to be used as the cathode and the middle of the chemical protection foil insulator 3. After forming the 1st conductive layer), the electrode for superposition | polymerization is connected. At this time, the soluble conductive polymer in the solution state, which is the first conductive layer 6, includes the entire dielectric oxide film 5 (cathode portion) and the insulator for protecting the foil (3) exposed to the lower portion of the shield for protecting the foil (3) used as the cathode. ) Formed by impregnation to the middle. Next, FIG. 2D shows a superconducting heterocyclic solid electrolyte layer 7 (hereinafter referred to as second conduction) by contacting the polymerizing electrode 4 over the soluble conductive polymer layer superimposed on the dielectric oxide film and the HF protective insulator 3. Layer) was formed by electrolytic oxidation polymerization, and then the electrode 4 for polymerization was removed. In this case, the second conductive layer 7 is formed only at the portion where the first conductive layer 1 is formed, and thus does not physically damage the dielectric oxide film 5. The second conductive layer 7 formed by this process serves as an electrolyte of the solid electrolytic capacitor. FIG. 2D shows that the carbon layer 8 and the silver paste layer 9 are formed of the conductive cathode layer having the multilayer structure for the solid electrolyte layer. Next, a lead frame is connected to the positive electrode 1 and the negative electrode 2 to produce a chip type solid electrolytic capacitor.

In addition, in order to expand the capacity of the product, a solid electrolyte and a metal foil having a conductive cathode layer are connected in parallel. At this time, the negative electrode uses a conductive adhesive. In order to reduce the welding defect due to the thickness of the metal foil laminated in parallel, the anode is fabricated by welding the portions by laminating metal foils of different positions in the same width.

A method of manufacturing the chip type electrolytic capacitor as described above will be described with reference to Examples.

First, a metal foil capable of forming a dielectric oxide film forms a dielectric oxide film layer through an etching and chemical conversion process. At this time, the etching foil produced diammonium adipate at the density | concentration of 150 g / L, and performed chemical conversion to 9V by the constant current of 10 mA / cm <2> at 60 degreeC. The area of the negative electrode portion on which the solid electrolyte and the conductive material are formed is cut to 6 × 4 mm, and then a chemical protection foil insulator is formed on the above-mentioned predetermined portion. The first conductive layer, the second conductive layer, carbon, and silver paste were sequentially formed on the intermediate layer of the HF protective insulator and the oxide film to be used as the cathode, and then the exterior was formed by a transfer molding method using an epoxy molding compound. The manufactured device is 6.3V, 10V class and ESR is 80mΩ (100㎑), which has very excellent device characteristics.

For evaluating the characteristics of the present invention, the leakage current characteristics and yields of the devices using the general insulator band and the chemical protection foil for insulator were compared. The value in Table 1 is the current value when 6.3V voltage is applied for 120 sec.

As shown in Table 1, the chip-type solid electrolytic capacitor manufactured by the manufacturing method of the present invention can be seen that the leakage current value and the yield of the product are improved than when using an insulator band. Dose values are shown.

Leakage Current Value and Product Yield Insulator band Hwaseong Foil Protective Insulator One 10.5 0.01 2 18.9 0.02 3 0.02 0.01 4 215 0.05 5 Defective 0.01 6 Defective 0.01 7 0.03 0.03 8 Defective 0.02 9 Defective 0.06 10 Defective 0.08 yield 20% 100%

Capacitance value of stacked devices Stacked Number Capacity 1 sheet 11 2 sheets 23 3 sheets 36 4 sheets 47

After forming a first conductive layer of a soluble conductive polymer in a solution state on a portion of the HF protective insulator and the dielectric oxide film below the HF protective insulator, the auxiliary electrode for polymerization overlaps the HF protective insulator and the first conductive layer. When the electrolytic polymerization is carried out by contacting from both sides of the place, the time can be shortened and a uniform second conductive layer can be obtained. In addition, leakage current characteristics and product yield are greatly improved after fabrication.

In addition, in order to increase the capacity of the product, when the anode foil is laminated with metal foils having different positions at the same width interval, the welding defects are greatly reduced, and the yield according to the capacity expansion can be improved.

Claims (5)

Forming a dielectric oxide film layer (5) on top of the metal foil to form an oxide film, Forming an insulator for protecting the chemical foil having electrical insulation and hardness to protect the oxide film layer during electrolytic polymerization on the dielectric oxide film layer; Forming an entire dielectric oxide film layer to be used as a cathode positioned below the HF protective insulator and the HF protective insulator by superimposing a soluble conductive polymer layer (first conductive layer) by a solution impregnation method; Forming a highly conductive solid electrolyte layer (second conductive layer) by electrolytic polymerization by contacting the electrodes for polymerization on both sides of the soluble conductive polymer layer superimposed on the HF protective insulator; And a carbon paste (8) and a silver paste (9), which are conductive cathode materials having a multilayer structure, are electrically connected to the lead frame in the solid electrolyte layer. The method of claim 1, In the electrolytic polymerization, the insulator for protecting the HF foil does not overlap a portion where the metal foil anode part is welded with the lead frame, and a part of the first conductive layer and the second conductive layer must be formed on the HF protective insulator. The method of manufacturing a chip-type solid electrolytic capacitor, characterized in that the overlapping structure. The method according to claim 1 or 2, The chemical protection foil protective insulator is formed using an epoxy resin, a fluorine resin, an acrylic resin, or the like. The method of claim 1, When stacking two or more elements having a cathode layer formed on the solid electrolytic capacitor, the anode foil drawn out from the cathode portion is cut left or right by the anode foil width spacing (a) when forming the second layer based on the metal foil of the lowermost layer. The third layer is also cut to the left or the right side by two times the width of the anode (2a) by the distance between the anode foil of the second layer is formed so that the anode foil of each layer is in direct contact with the lead frame and electrically connected. Method of manufacturing an electrolytic capacitor. The method of claim 4, wherein The positive electrode foils having different positions of the same width may be electrically connected to the anode lead frame 11 by using spot welding, ultrasonic welding, laser welding, stitch, or the like. Method for manufacturing a capacitor