JP2010278033A - Surface mount thin capacitor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mount thin capacitor having a short construction period and stable electric characteristics, and a solid electrolyte of the manufacturing method thereof.
A surface-mount thin capacitor using a valve-acting metal having an enlarged surface comprising a metal core portion and an etched layer covering both surfaces of the metal core portion as a base material. The first conductive polymer layer 12 and the second conductive polymer layer 14 are formed, and the first conductive polymer layer 12 is regularly formed on the surface of the dielectric layer 1. .
[Selection] Figure 1

Description

  The present invention relates to a surface mount thin capacitor and a method for manufacturing the same, and more particularly to a surface mount thin capacitor using a metal foil as a base material and a method for manufacturing the same.

  In recent years, information electronic devices such as mobile phones have been widely used in the world. These information electronic devices use digital circuit technology. Recently, digital circuit technology such as LSI is also used in computers, communication-related devices, home appliances, and in-vehicle devices. Furthermore, it is known that when the above-described LSI is operated, a high-frequency current is generated in the power supply line of the LSI. As a countermeasure, it is effective to separate the LSI, which is the source of the high-frequency current, from the power supply system at high frequency, that is, a power supply decoupling technique. When using a capacitor to remove electrical noise over a wide frequency band, multiple types of capacitors, such as different types of capacitors such as aluminum electrolytic capacitors, tantalum capacitors, and ceramic capacitors with different self-resonant frequencies, are located near the LSI. It has been done by providing multiple.

  Conventionally, solid electrolytic capacitors using aluminum, tantalum, or the like as a valve metal have been widely used in CPU decoupling circuits or power supply circuits because they are small and have a large capacitance and excellent frequency characteristics. In particular, the development of surface mount type solid electrolytic capacitors having low ESR (equivalent series resistance) and low ESL (equivalent series inductance) at high frequencies is in progress.

  FIG. 3 shows a cross-sectional view of a capacitor element used in a conventional surface mount thin capacitor.

  A conventional technique will be described with reference to FIG. In this type of surface-mount thin capacitor, an anodic oxide film 1 is formed on the surface of an anode body 10 obtained by enlarging a plate-like or foil-like metal having a valve action, and the anode body 10 is formed by a resist layer 13. A conductive polymer layer 11 is formed as a solid electrolyte so as to cover the surface of the anodic oxide film 1 at the center and separate the anode portion, and then a graphite layer 15 as a cathode layer is formed thereon. The silver paste layer 16 is sequentially formed to manufacture the capacitor element 17. The technology of such a surface mount thin capacitor is disclosed in Patent Document 1.

  However, in the conventional surface mount thin capacitor having such a structure, when chemical oxidative polymerization is used in forming the conductive polymer layer 11, an oxidant solution and a monomer solution are alternately immersed a plurality of times as a polymerization solution. At that time, since the surface of the anode body 10 is smooth, the polymerization solution flows down without adhering to the anode body 10, and since the polymerization solution is not retained, it is difficult to form a uniform polymerization layer and it is difficult to obtain stable electrical characteristics. become. In addition, in order to solve this problem, there has been a problem that the manufacturing time is prolonged by repeating the immersion many times.

JP 2005-159154 A

  A technical problem of the present invention is to provide a surface mount thin capacitor having stable electric characteristics and a method of manufacturing the same without performing a large number of polymerization solution immersions.

  According to the present invention, a surface-enhanced valve action metal composed of a metal core part and an etched layer covering both surfaces of the metal core part is used as a base material, A dielectric layer made of an oxide film is formed, both ends are used as anodes, and a first conductive layer formed in a regular pattern on a part of the surface of the dielectric layer in the central portion. A surface-mount thin capacitor comprising a conductive polymer layer and a second conductive polymer layer formed on the entire dielectric layer is obtained.

  According to the present invention, there is obtained a surface mount thin capacitor characterized in that the first conductive polymer layer is formed by printing a conductive polymer dispersion.

  Further, the first conductive polymer layer has a protrusion on a part of the surface of the dielectric layer, and the protrusion has a lattice shape, a stripe shape, and a plurality of circular shapes. A characteristic surface mount thin capacitor is obtained.

  According to the present invention, an expanded valve action metal composed of a metal core portion and an etched layer covering both surfaces of the metal core portion is used as a base material, and an oxide film is formed on the surface of the expanded valve action metal. Forming a dielectric layer comprising: both ends are used as anodes, and a first conductive polymer layer is formed with a regular pattern in part on the surface of the central portion of the capacitor element. And a method of manufacturing a surface mount thin capacitor, comprising: forming a second conductive polymer layer on the first conductive polymer layer and the dielectric layer. .

  In addition, a method for manufacturing a surface mount thin capacitor is obtained, wherein the step of forming the first conductive polymer layer includes a step of forming by printing.

  According to the present invention, it is possible to provide a mounted thin capacitor having stable electrical characteristics with a smaller number of times of immersion of the polymerization liquid.

Sectional drawing of the capacitor | condenser element in embodiment of this invention. FIG. 2 (a) shows the shape of the first polymerization layer in the front view after the formation of the first polymerization layer in the embodiment of the present invention, FIG. 2 (a) shows a striped shape, FIG. 2 (b) shows a lattice shape, FIG. 2C is a front view showing a circular shape. Sectional drawing of the capacitor | condenser element used for the conventional surface mount thin capacitor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a capacitor element according to an embodiment of the present invention. A dielectric layer 1 is formed by subjecting the anode body 10 whose surface is enlarged by etching or the like to the valve action metal such as Al, Ti, Ta, Nb, etc., here Al by an electrochemical method. After forming the dielectric layer 1, the dielectric film and the electrolyte layer at the boundary portion between the anode and the cathode are partially removed to expose both ends of the anode body 10. Thereafter, an insulating resin is formed on the exposed portions at both ends of the anode body 10 by a screen printing method or the like to separate the anode and the cathode as the resist layer 13. Thereafter, the resist layer 13 is dried and cured, and then the anode body 10 is formed with a DC voltage.

  Thereafter, the first conductive polymer layer 12 is formed on the surface of the anode body 10. Examples of the forming method include an ink jet method or a method by screen printing. The surface of the anode body 10 has a convex shape, and a striped, latticed, or circular conductive polymer layer is formed. It forms so that a location and an unformed location may exist regularly.

  Then, after dipping in an oxidizer solution such as iron sulfonate and ammonium persulfate, it is dried. Thereafter, it is immersed in a monomer solution such as 3,4-ethylenedioxythiophene or pyrrole. By repeating the cycle a plurality of times, the second conductive polymer layer 14 is formed by chemical oxidative polymerization.

  After the formation of the conductive polymer layer 14, a graphite layer 15 and a silver paste layer 16 are formed to obtain a capacitor element 17 as a cathode layer.

  An embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a capacitor element 17 used in the embodiment, and FIG. 2 is a front view after the formation of the first conductive polymer layer, showing the shape of the first conductive polymer layer. FIG. 2A is a front view showing a stripe shape, FIG. 2B is a lattice shape, and FIG. 3C is a circular shape.

  As shown in FIG. 1, an anode body 10 is formed by expanding an aluminum foil (width 10 mm, length 15 mm, thickness 150 μm), which is a valve action metal, and then a 3 V DC voltage is applied electrochemically. A dielectric film was formed.

  After the formation of the dielectric film, a first conductive polymer layer 12 is formed on the anode body 10 as shown in FIG. The formation is arranged in a striped manner as shown in FIG. 2A, a lattice shape as shown in FIG. 2B, and a circular shape as shown in FIG. Here, the striped pattern in FIG. 2A will be described in detail.

  After forming a printing plate with a stripe interval of 0.2 mm and a stripe width of 0.2 mm on a screen printing plate, a slurry polymer (viscosity 400 mPa · S) in which a conductive polymer powder is dispersed in a solution is used. It apply | coated to the printing plate, and after printing on the anode body 10, it dried at 150 degreeC for 30 minutes. Thereafter, the remaining one surface was printed and dried in the same manner to form a striped first conductive polymer layer 12 having a convex portion having a thickness of 5 μm as shown in FIG. .

  Thereafter, the capacitor element is immersed in ferric benzene sulfonate solution for 30 seconds, dried for 5 minutes, and then immersed in monomer 3,4-ethylenedioxythiophene for 30 seconds for 45 minutes. It was allowed to stand and a chemical oxidative polymerization reaction was performed to form polythiophene as a conductive polymer layer on the entire dielectric layer.

  The aforementioned immersion cycle was repeated 5 times to form the second conductive polymer layer 14, and then the graphite layer 15 and the silver paste layer 16 were formed thereon to obtain the capacitor element 17.

(Comparative example)
As a comparative example, the capacitor element described in the previous example except that the first conductive polymer layer 12 before forming the second conductive polymer layer 14 was not formed and the chemical oxidation polymerization was performed 17 times. Got.

  Table 1 shows the number of polymerizations and the capacities of the examples and comparative examples, and the equivalent series resistance (hereinafter referred to as ESR) values. As can be seen from Table 1, this example has a smaller number of polymerizations than the comparative examples. Regardless, the conductive polymer layer, which is a solid electrolyte, had the same thickness, and stable electrical characteristics equivalent to those of the comparative example could be obtained.

  From the above results, according to the present invention, the amount of the polymer solution adhered by the pulling up after immersion of the polymer solution is increased, and further, the polymerization solution is prevented from sagging during the polymerization standing time, thereby forming the capacitor element 17 per one polymerization step. The thickness of the conductive polymer layer formed increased, and the same or better electrical characteristics could be obtained even with a small number of polymerizations.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and design changes within a range not departing from the gist of the present invention are also included in the present invention. That is, it goes without saying that various modifications and corrections that can be made by those skilled in the art are included.

  The surface-mount thin capacitor according to the present invention can be applied to a solid electrolytic capacitor of a type that is surface-mounted on a substrate such as a printed wiring board of an electronic component or an electrical component.

DESCRIPTION OF SYMBOLS 1 Dielectric layer 10 Anode body 11 Conductive polymer layer 12 1st conductive polymer layer 13 Resist layer 14 2nd conductive polymer layer 15 Graphite layer 16 Silver paste layer 17 Capacitor element

Claims (8)

  A surface-enhanced valve metal comprising a metal core and an etched layer covering both surfaces of the metal core is used as a base material, and the surface of the surface-enhanced valve metal is a dielectric made of an oxide film. A first conductive polymer layer formed with a regular pattern on a part of the surface of the dielectric layer at a central portion and the both ends are used as anodes, A surface-mount thin capacitor comprising a second conductive polymer layer formed on the entire dielectric layer.   The surface-mount thin capacitor according to claim 1, wherein the first conductive polymer layer is formed by printing a conductive polymer dispersion.   2. The surface mount thin capacitor according to claim 1, wherein the first conductive polymer layer has a convex portion on a part of the surface of the dielectric layer.   3. The surface mount thin capacitor according to claim 2, wherein the first conductive polymer layer is arranged in a lattice pattern.   3. The surface mount thin capacitor according to claim 2, wherein the first conductive polymer layer is arranged in a striped pattern.   3. The surface mount thin capacitor according to claim 2, wherein the first conductive polymer layer is arranged in a plurality of circles.   A valve layer metal having an enlarged surface consisting of a metal core and an etched layer covering both surfaces of the metal core is used as a base material, and a dielectric layer made of an oxide film is formed on the surface of the expanded valve metal. Forming the first conductive polymer layer having a regular pattern in part on the surface of the capacitor element center portion, the both end portions being used as anodes, and the first step A method for producing a surface mount thin capacitor, comprising a step of forming a second conductive polymer layer on one conductive polymer layer and the dielectric layer.   The method for producing a surface mount thin capacitor according to claim 8, wherein the step of forming the first conductive polymer layer includes a step of forming by printing.

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