WO2010113978A1 - Solid electrolytic capacitor - Google Patents

Abstract

Provided is a capacitor, the transient response characteristics of which are excellent by reducing the ESL of a solid electrolytic capacitor more using the solid electrolytic capacitor with the ease of an increase in capacitance, and which is available as a distributed constant noise filter, and as a composite component having two functions of the capacitor and the distributed constant noise filter. Two capacitor element pieces (121) in which both ends of an anode body are rendered as anode lead-out sections (122, 122) and both surfaces of the center part of the anode body are rendered as cathode lead-out sections (123) are prepared. The two capacitor element pieces (121, 121) are stacked in such a manner that the cathode lead-out sections (123, 123) overlap each other and the anode lead-out sections (122, 122) are misaligned at approximately right angles to each other, thereby obtaining a capacitor element (120). As the mounting substrate (141), a mounting substrate (141) is prepared which is provided with conductors (144, 145) consistent with the anode lead-out sections (122, 122) and cathode lead-out sections (123) of the capacitor element on the mount surface and is provided with anode terminal sections (142) and a cathode terminal section (143) on the installation surface, and in which the conductors (144, 145), the anode terminal sections (142), and the cathode terminal section (143) are subjected to through-hole connection. The capacitor element (120) is mounted on the mounting substrate (141) to create the solid electrolytic capacitor.

Description

Solid electrolytic capacitor

The present invention relates to a solid electrolytic capacitor. More specifically, the present invention can function as a solid electrolytic capacitor having a low equivalent series inductance as electrical characteristics and good transient response characteristics, or a distributed constant noise filter. The present invention relates to a solid electrolytic capacitor.

Along with the increase in frequency of electronic equipment, capacitors that are one of the electronic components have been required to have better impedance characteristics in the high frequency range than before. Various solid electrolytic capacitors using a highly conductive polymer as a solid electrolyte have been studied.

In recent years, LSIs such as CPUs typified by computers, LSIs for image processing of televisions, and memories that exchange data with these LSIs have been placed around these devices for power supply applications. A solid electrolytic capacitor to be used is strongly demanded to be small in size and large in capacity. Further, in addition to low ESR (equivalent series resistance) corresponding to high frequency, low ESL (excellent noise removal and transient response) ( Equivalent series inductance) is strongly demanded, and various studies have been made to meet such a demand.

As a capacitor, for example, a solid electrolytic capacitor using a conductive polymer compound as a solid electrolyte, that is, a cathode electrode layer, the one shown in FIG. 13 is known. FIG. 13 is a cross-sectional view showing a conventional solid electrolytic capacitor. A dielectric layer made of an oxide film is formed on the anode body 304 made of a valve metal, and then a solid electrolyte layer (cathode electrode layer) 305 made of a conductive polymer is formed on the dielectric layer, and further around that After the graphite layer 306 is formed and the cathode layer composed of the silver paste layer 307 is sequentially formed, the anode lead 309 is connected to the other end side of the anode body 304, and the cathode lead 310 is connected to the lower surface of the silver paste layer 307. It is connected and pulled out and molded with exterior resin 308. Such a solid electrolytic capacitor is disclosed in Patent Document 7.

Generally, as a method for reducing the ESL, firstly, the current path is made as short as possible, and secondly, the magnetic field formed by the current path is canceled by the magnetic field formed by another current path. A third method is known in which the current path is divided into n and the effective ESL is reduced to 1 / n.

For example, the invention disclosed in Japanese Patent Laid-Open No. 2000-311832 employs the first and third methods, and the invention disclosed in Japanese Patent Laid-Open No. 06-267802 discloses the second and third methods. The invention disclosed in Japanese Patent Laid-Open No. 06-267801, Japanese Patent Laid-Open No. 11-288846, and Japanese Patent No. 4208831 employs the third method.

Japanese Patent Laid-Open No. 2002-164760 discloses a distributed constant type noise filter using a conductive polymer as an electrolyte, in which two flat plate-shaped oxide films are formed of a plate-shaped valve metal. An anode terminal having a distributed constant circuit forming portion sandwiched between the cathode terminal connected to the distributed constant circuit forming portion and an anode lead portion protruding from an oxide film in which a part of the valve action metal plate is a dielectric is provided. A three-terminal capacitor type distributed constant noise filter is disclosed.

FIG. 14 is a cross-sectional view showing a conventional distributed constant noise filter. A solid electrolyte (cathode electrode layer) 405, a graphite layer 406, and a silver paste layer 407 made of a conductive polymer are sequentially formed on the surface of the central portion of the dielectric layer formed on the anode body 404 of the valve metal to form a cathode. Both ends of the body 404 are a pair of anodes, anode leads 409 are connected to both ends thereof, cathode leads 410 are connected to the central silver paste layer 407, and molded with exterior resin 408. This distributed constant type noise filter utilizes the structure of a three-terminal type solid electrolytic capacitor and can also function as a solid electrolytic capacitor.

Japanese Unexamined Patent Publication No. 2000-311832 Japanese Unexamined Patent Publication No. 06-267802 Japanese Unexamined Patent Publication No. 06-267801 Japanese Laid-Open Patent Publication No. 11-288846 Japanese Patent No. 4208831 Japanese Unexamined Patent Publication No. 2002-164760 Japanese Unexamined Patent Publication No. 09-260215

Among the above-mentioned documents, the capacitor disclosed in Patent Document 1 can cope with high frequency by using a thin film capacitor, but in order to increase the capacitance, is it necessary to increase the area of the dielectric layer? It is necessary to laminate dielectric layers. The dielectric layer used is a perovskite-type complex oxide crystal containing Ba and Ti, and the realizable capacitance is nanofarad (nF) order capacitance, and microfarad (μF). There is a disadvantage that it is difficult to adopt when a capacitance of the order is required.

Further, in the solid electrolytic capacitors disclosed in Patent Document 2 and Patent Document 4, the current path is divided by making the solid electrolytic capacitor into four terminals, so that the solid electrolytic capacitor is more than the conventional two-terminal type solid electrolytic capacitor. To reduce ESL.
However, Patent Document 2 has a structure in which an external anode terminal and an external cathode terminal are attached to the capacitor element, and the current path inside the solid electrolytic capacitor is not necessarily short.

Further, in the solid electrolytic capacitor disclosed in Patent Document 4, the anode and cathode terminals are arranged on the four side surfaces of the solid electrolytic capacitor, and the four terminals are separated from each other, which is called cancellation of the induced magnetic field. The effect cannot be expected.

In the solid electrolytic capacitor described in Patent Document 3, a plurality of metal substrate portions positioned between the capacitor portions and the capacitor portions are bent in a zigzag shape in opposite directions, and the capacitor portions are joined to each other and laminated. Since the metal substrates located at both ends of the capacitor portion of the solid capacitor unit plate are joined so that all the metal substrates are connected in series, the bent metal substrate portions or the metal substrate portions joined to each other act as a coil and are laminated. The solid electrolytic capacitor is configured as a kind of filter circuit. Then, by covering the periphery of the bent metal substrate portion or the metal substrate portions joined to each other with a magnetic material, this multilayer solid electrolytic capacitor is configured as an effective filter device by combining a capacitor and a coil. Although it has been shown that it can be used as a noise absorbing device in a high frequency region, since a lead frame is used as a current path from the capacitor element inside the solid electrolytic capacitor to the external electrode, There is a problem that the current path inside the electrolytic capacitor becomes redundant and the ESL reduction effect is not sufficient.

In the solid electrolytic capacitor disclosed in Patent Document 5, a pseudo 5-terminal type solid electrolytic capacitor is adopted, and the current path of the anode is divided into four to reduce the effective ESL. However, since the lead frame is used as a current path from the capacitor element inside the solid electrolytic capacitor to the external electrode, the current path inside the solid electrolytic capacitor becomes redundant, and the ESL reduction effect is not sufficient. I have a problem.

As described above, the solid electrolytic capacitors described in Patent Document 1 to Patent Document 5 described above have an ESL reduction effect and are expected to improve transient response characteristics as compared with the conventionally known two-terminal capacitors. However, it has not always obtained a sufficient effect for the low ESL requirement recently required.

The solid electrolytic capacitors described in Patent Document 1 to Patent Document 5 described above are solid electrolytic capacitors for the purpose of reducing ESL, and are not intended for the function as a transmission line. In addition, although patent document 2, patent document 3, and patent document 5 are 3 terminal type solid electrolytic capacitors, it is thought that it can also be utilized as a transmission line, but when using these as a transmission line, Therefore, it cannot be used as a solid electrolytic capacitor for transient response, and has a single function.

On the other hand, a distributed constant type noise filter disclosed in Patent Document 6 is known as a noise filter having a three-terminal type solid electrolytic capacitor and having a transmission line structure. It has only a single function and cannot sufficiently meet the demand for transient response characteristics.

That is, the capacitor is arranged near the CPU, and a capacitor having a function with excellent transient response characteristics for quickly supplying power to an instantaneous voltage drop of the CPU is required. The noise filter is also arranged near the CPU. Therefore, it is required to remove the high frequency noise of the power supplied to the CPU and stabilize the operation of the CPU. For this reason, it is desirable that the capacitor and the noise filter are respectively disposed in the vicinity of the CPU, but there are restrictions on disposing them all in the vicinity of the CPU due to the limitation of the mounting area.

Therefore, there is a demand for a device that has both of these functions and can be used as a capacitor alone or as a distributed constant noise filter, and as a capacitor and a distributed constant noise filter.

The present invention has been made in view of the above-described problems. By using a solid electrolytic capacitor in which the capacitance can be easily increased, the transient response characteristic is improved by further reducing the ESL of the solid electrolytic capacitor. An object of the present invention is to provide a capacitor that is good and can be used as a composite component having two functions of a capacitor and a distributed constant noise filter as a distributed constant noise filter.

The above object of the present invention is achieved by the following configurations.
(1) Capacitor element pieces having both ends of the anode body as anode lead portions and both sides of the central portion of the anode body as cathode lead portions, the cathode lead portions overlap and the anode lead portions are substantially perpendicular to each other It is characterized by being a solid electrolytic capacitor having capacitor elements laminated so as to deviate from each other.

(2) In the solid electrolytic capacitor described in (1) above, the cathode lead portions on the side surfaces of the stacked capacitor element pieces are connected to each other with a conductive material.

(3) A mounting surface facing a wiring board in a solid electrolytic capacitor having a capacitor element in which both ends of an anode body are anode lead portions and a dielectric layer, a solid electrolyte layer, and a cathode lead portion are sequentially formed on the anode body. A first cathode terminal portion in the middle of the first cathode terminal portion, an anode terminal portion around the first cathode terminal portion, and a second cathode terminal portion adjacent to the anode terminal portion. It is a capacitor.

(4) Capacitor element in which both ends of the anode body are anode extraction portions, and a dielectric layer, a solid electrolyte layer, and a cathode extraction portion are sequentially formed on the anode body, a surface on which the capacitor element is mounted, and a surface on the wiring board A conductor surface corresponding to the anode lead portion and the cathode lead portion of the capacitor element is formed on the surface on which the capacitor element is mounted, and an anode terminal is provided on the mounting surface facing the wiring board. And a cathode terminal portion, and the conductor comprises a mounting substrate that penetrates the wiring board and is electrically connected to the anode terminal portion and the cathode terminal portion, respectively, on the mounting surface of the mounting substrate. The first cathode terminal portion is arranged at the center thereof, and the anode terminal portion is arranged on four sides of the mounting surface of the mounting substrate around the first cathode terminal portion, and the mounting surface of the mounting substrate is At the four corners Characterized in that it is a solid electrolytic capacitor which arranged the second cathode terminal portion adjacent to the anode terminal Te.

(5) In the solid electrolytic capacitor described in (3) or (4) above, the first cathode terminal portion is formed in a region substantially equal to the size of the cathode lead portion of the capacitor element, and the anode terminal portion And it is set as the area | region larger than the said 2nd cathode terminal part.

(6) In the solid electrolytic capacitor according to any one of (3) to (5), the first cathode terminal portion is a central portion of the mounting surface of the mounting board and is close to each anode terminal portion. And an insulating region is formed at the center of the mounting surface.

(7) A solid electrolytic capacitor comprising a rectangular mounting substrate having a mounting surface that is surface-mounted on a printed circuit board on one surface and an element mounting surface on which the capacitor element is mounted on the other surface, and a capacitor element. The mounting substrate has anode terminal portions at the four corners of the mounting surface and cathode terminal portions at the central portion, anode conductors connected to the anode terminal portions at the four corners of the element mounting surface, and a central portion. Cathode conductors that are electrically connected to the cathode terminal portion are respectively disposed, and the capacitor element has a capacitance forming portion, a cathode electrode layer, and a cathode lead portion sequentially laminated at a central portion of the conductor, and from the periphery of the cathode lead portion. An anode lead portion comprising four protruding conductors is formed, the anode lead portion of the capacitor element is formed on the anode conductor of the mounting substrate, and the cathode of the capacitor element is formed on the cathode conductor. Out section was connected, characterized in that it is a solid electrolytic capacitor comprising a transmission line structure by conductor in the capacitor element positioned diagonally of the mounting substrate.

(8) In the solid electrolytic capacitor as described in (7) above, the capacitor element is made of a rectangular conductor, and the anode lead portion protrudes from both ends of the cathode lead portion into a cruciform shape. It is characterized in that a plurality of layers are stacked.

(9) In the solid electrolytic capacitor described in (7) above, the capacitor element is made of a cross-shaped conductor, and the anode lead portion protrudes from the periphery of the cathode lead portion.

According to the solid electrolytic capacitor described in the above (1), the capacitor lead-out part overlaps the capacitor element piece with both ends of the anode body as the anode lead-out part and both surfaces of the central part of the anode body as the cathode lead-out part, By forming a solid electrolytic capacitor using capacitor elements that are laminated so that the anode lead portions deviate from each other at right angles, the anode lead portions are formed at four locations, and the current path can be divided into four parts. ESL can be reduced to 1/4.

In addition, the anode lead portions arranged opposite to each other are electrically connected inside the capacitor element pieces, and further have a cathode lead portion sandwiched between the anode lead portions, thereby constituting a transmission line structure. It can also function as a three-terminal noise filter. That is, when this solid electrolytic capacitor is mounted on a circuit board, an electric signal input from one of the opposing anode lead portions is filtered, and the electric signal is output to the other anode lead portion. On the other hand, in the solid electrolytic capacitor of the present invention, the laminated capacitor element pieces can be regarded as independent capacitors in terms of electrical circuits. In addition, when viewed as a transmission line structure, the capacitor element pieces constituting the transmission line structure intersect each other, so that there is little mutual influence. For this reason, a pair of anode lead portions facing each other is used as a noise filter, and a pair of anode lead portions arranged at a rotation angle perpendicular to the anode lead portion functioning as the noise filter is used as an output terminal of a capacitor for transient response. It is also possible to do. It is also possible to use the two capacitor element pieces as transmission lines.

According to the solid electrolytic capacitor described in (2) above, the internal resistance of the cathode lead portions of the stacked capacitor elements is reduced by connecting the side surfaces of the cathode lead portions of the stacked capacitor element pieces with a conductive material. Reduction can be achieved. For this reason, since the charge accumulated in the capacitance forming part of the laminated capacitor element can be quickly supplied from any of the four anode lead parts, the solid electrolytic capacitor as a whole has excellent transient response characteristics. A capacitor can be obtained.

According to the solid electrolytic capacitor described in (3) above, a solid having a capacitor element in which both ends of the anode body are anode extraction portions, and a dielectric layer, a solid electrolyte layer, and a cathode extraction portion are sequentially formed on the anode body. In the electrolytic capacitor, the first cathode terminal portion is arranged at the center of the mounting surface facing the wiring board, and the anode terminal portion is arranged around the first cathode terminal portion, and is adjacent to the anode terminal portion. By arranging the two cathode terminal portions, first, the distance from the anode lead portion and the cathode lead portion of the capacitor element to the anode terminal portion and the cathode terminal portion of the mounting substrate, which is the current outlet, is as follows. This can be achieved only by the thickness, and the current path can be shortened. Secondly, since the anode terminal portion of the mounting substrate is arranged so that the three directions are surrounded by the cathode terminal portion, the effect of canceling the induced magnetic fields of the anode and the cathode is large, and the ESL of the solid electrolytic capacitor can be reduced. .

According to the solid electrolytic capacitor described in (4) above, as the mounting substrate for the solid electrolytic capacitor, the anode mounting portion of the capacitor element, the anode conductor corresponding to the cathode leading portion, and the cathode conductor are provided on the surface on which the capacitor element is mounted. Each of the mounting substrates has a first cathode terminal portion in the center of the mounting substrate and four anode terminal portions on the four sides of the mounting substrate so as to surround the outer periphery of the first cathode terminal portion. In addition, second cathode terminal portions electrically connected to the cathode lead portions of the capacitor elements are provided at the four corners of the mounting substrate. Since the second cathode terminal portion is disposed adjacent to the anode terminal portion, the anode terminal portion is surrounded in three directions by the first cathode terminal portion and the second cathode terminal portion, respectively. Arrangement. And, by the configuration in which the anode conductor and the anode terminal portion, and the cathode conductor and the cathode terminal portion are electrically connected by conductors penetrating the mounting substrate, respectively, first, from the anode lead portion and the cathode lead portion of the capacitor element, The distance to the anode terminal portion and the cathode terminal portion of the mounting substrate, which is the current outlet, can be achieved by a distance corresponding to the thickness of the mounting substrate, and the current path can be shortened. Second, since the anode terminal portion of the mounting substrate is arranged so that three directions are surrounded by the cathode terminal portion, the effect of canceling the induced magnetic fields of the anode and the cathode is large. Third, by forming the anode terminal portion at four locations, the current path can be divided into four, and the substantial ESL can be reduced to ¼.

That is, in the solid electrolytic capacitor of the present invention, a method of shortening the length of the current path as the first element technology for reducing ESL and a magnetic field formed by the current path as the second element technique are separated. Using all the methods of canceling by the magnetic field formed by the current path of the current, and dividing the current path, which is the third elemental technology, into n pieces and reducing the effective ESL to 1 / n, Thus, it is possible to realize a solid electrolytic capacitor with an increased reduction effect.

According to the solid electrolytic capacitor described in (5) above, the first cathode terminal portion disposed in the center of the mounting surface is formed in a region substantially equal to the size of the cathode lead portion of the capacitor element, and the anode terminal portion Since the area is larger than that of the second cathode terminal portion, the distance from the cathode lead portion of the capacitor element to the first cathode terminal portion can be formed to be the shortest, and ESL can be reduced. At the same time, the current capacity output from the cathode lead portion of the capacitor element can be increased, and the cathode terminal portion can supply a large current during a transient response.

According to the solid electrolytic capacitor described in (6) above, the first cathode terminal portion is disposed in the central portion of the mounting surface and in the vicinity of each anode terminal portion, and the central portion is an insulating region. As a result, the current is concentrated by narrowing the current path of the first cathode terminal portion, and the effect of canceling the induced magnetic field can be further enhanced by bringing the current path closer to the anode terminal portion. That is, it is possible to realize a solid electrolytic capacitor that further enhances the overall ESL reduction effect.

According to the solid electrolytic capacitor described in the above (7), it functions as a five-terminal capacitor in which the anode terminal portion is led out in four directions and the cathode terminal portion is arranged in the center portion. Furthermore, the capacitor element is formed by sequentially laminating a capacitance forming portion, a cathode electrode layer, and a cathode lead portion at the center of the conductor, and an anode lead portion comprising four conductors protruding from the periphery of the cathode lead portion is formed. And the anode terminal parts located diagonally comprise the transmission line structure with the conductor. Since the dielectric layer and the cathode electrode layer serving as the capacitance forming portion of the capacitor element can function as a distributed constant circuit, it can function as a three-terminal noise filter using the distributed constant circuit portion as a filter portion. That is, when this capacitor is mounted on a circuit board, an electrical signal input from one of the opposing anode terminal portions arranged diagonally is filtered by the distributed constant circuit portion, and the electrical signal is filtered by the other anode terminal portion. Will be output.

And the transmission line structure of the capacitor element is a crossed structure. Therefore, the crossed transmission line structures can be regarded as independent transmission lines in terms of electrical circuits. When the solid electrolytic capacitor or the capacitor of the present invention is viewed as a distributed constant type noise filter, the transmission line structure is orthogonal, and the phase of the induced magnetic field generated from each transmission line is shifted, so that there is little mutual influence.

And, if the transmission line structure is composed of the anode terminal portions arranged diagonally, the length of the transmission line on a fixed rectangular mounting surface can be made the longest. As a result, the distributed constant circuit portion formed on the transmission line can be formed longer. In general, in order to function as a noise filter with high efficiency, it is desirable that the length of the distributed constant circuit unit is ¼λ or more when the wavelength of the input noise wave is λ. Therefore, in order to function as a noise filter that can cope with a wideband frequency, the longer the distributed constant circuit portion, the better.

For this reason, in the solid electrolytic capacitor described in (7) above, the transmission line length is the longest among the solid electrolytic capacitors having a fixed mounting area, and the length of the distributed constant circuit portion on the transmission line can be increased. Therefore, it becomes possible to reduce the size of the noise filter corresponding to broadband noise.

Further, when viewed as a solid electrolytic capacitor, a five-terminal solid electrolytic capacitor having a cathode terminal portion at the center and four anode terminal portions around the cathode terminal portion is obtained. Thus, by setting it as a five-terminal solid electrolytic capacitor, the current path can be divided into four, and the substantial ESL of the solid electrolytic capacitor can be reduced to ¼.

Furthermore, in the solid electrolytic capacitor described in (7), one of the crossed transmission line structures can be used as a solid electrolytic capacitor, and the other can be used as a distributed constant noise filter. Can be used.

It is drawing which shows the shape of the capacitor | condenser element piece used for the solid electrolytic capacitor of the 1st Embodiment of this invention, (a), (b) is sectional drawing, (c) is a top view. It is a perspective view showing the shape of a capacitor element piece and a capacitor element used for the solid electrolytic capacitor of the 1st embodiment of the present invention, (a) shows a capacitor element piece, and (b) shows a capacitor element. It is drawing which shows the shape of the mounting substrate used for the solid electrolytic capacitor of the 1st Embodiment of this invention, (a) is a mounting surface of a capacitor | condenser element, (b) is drawing which shows a mounting surface. It is sectional drawing of the mounting substrate used for the solid electrolytic capacitor of the 1st Embodiment of this invention. It is drawing which shows the solid electrolytic capacitor of the 1st Embodiment of this invention, (a) is a top view, (b) is sectional drawing. It is drawing which shows the shape of the mounting substrate used for the solid electrolytic capacitor of the 2nd Embodiment of this invention, (a) is a mounting surface of a capacitor | condenser element, (b) is drawing which shows a mounting surface. It is sectional drawing of the mounting substrate used for the solid electrolytic capacitor of the 2nd Embodiment of this invention. It is drawing which shows the solid electrolytic capacitor of the 2nd Embodiment of this invention, (a) is a top view, (b) is sectional drawing. It is drawing which shows the modification of the mounting substrate used for the solid electrolytic capacitor of the 2nd Embodiment of this invention, (a) is a surface which mounts a capacitor | condenser element, (b) is drawing which shows a mounting surface. 4A and 4B are views showing a third embodiment of the present invention, where FIG. 5A is a top view of the solid electrolytic capacitor, and FIG. 5B is a cross-sectional view taken along line AA in FIG. It is drawing which shows the modification of the 3rd Embodiment of this invention. It is drawing which shows the mounting substrate used for the solid electrolytic capacitor of the 3rd Embodiment of this invention, (a) is an element mounting surface, (b) is drawing which shows a mounting surface. It is sectional drawing which shows the internal structure of the conventional solid electrolytic capacitor. It is sectional drawing which shows the internal structure of the conventional distributed constant type noise filter.

Next, a mode for carrying out the present invention will be described in detail.

(First embodiment)
First, a capacitor element used for the solid electrolytic capacitor according to the first embodiment of the present invention will be described. The capacitor element used for the solid electrolytic capacitor according to the first embodiment of the present invention has a rectangular capacitor element piece in which both ends are an anode lead portion and a central portion between the anode lead portions is a cathode lead portion. The capacitor element pieces are shifted and overlapped so that the anode lead portions are oriented at a right angle of rotation angle, and the central portion becomes the cathode lead portion, and the anode lead portions are arranged in four directions from the cathode lead portion. It is a formed form.

Such a capacitor element will be described in more detail below.
As shown in FIG. 1, the capacitor element piece 121 uses a valve metal plate or valve metal foil (hereinafter referred to as an anode body) made of substantially rectangular aluminum or the like, and the central portion of the anode body is enlarged by an etching process. A porous etching layer 125 is formed on both sides of the aluminum foil by processing. At this time, the inside of the anode body is not etched and an aluminum ingot remains, and this aluminum ingot becomes a remaining core layer ((a) of FIG. 1). A dielectric oxide film is formed on the surface of the etching layer 125 by anodic oxidation. In this case, both end portions of the anode body are unetched portions and become anode lead portions 122. Next, a dielectric oxide film is formed on the surface of the etching layer 125 by anodic oxidation.

More specifically, the etching treatment is a step of forming a porous etching layer by dissolving both surfaces of the anode body with hydrochloric acid or the like. For example, an anode body made of a high-purity aluminum foil having a cross-sectional size of 10 mm × 5 mm and a thickness of 120 μm is used, and a resist material is applied to the positions of 1.5 mm from both ends of the anode body, respectively. (Not shown). After forming the resist protective film, an etching layer is formed in the central part of the anode body at a depth of 40 μm from both sides. In this case, the thickness of the remaining core layer is 40 μm.

A separation layer 124 is formed on the capacitor element piece, and the anode lead portion 122 and the cathode lead portion 123 of the capacitor element piece 121 are separated. After the etching is finished, the separation layer 124 is coated with an insulating resin and penetrated into the etching layer 125 to insulate the anode lead portion 122 and the etching layer 125. For example, the separation layer 124 can be formed to a position of 0.5 mm from the unetched portion.

Then, the etched anode body is subjected to chemical conversion treatment by anodization to form a dielectric oxide film layer made of aluminum oxide. In the anodic oxidation, a predetermined voltage is applied in a state where the etching foil is immersed in an aqueous solution such as boric acid or adipic acid to form a dielectric oxide film.

Further, a solid electrolyte layer (not shown) is formed on the dielectric oxide film. The solid electrolyte layer is sequentially immersed in a solution containing a polymerizable monomer that becomes a conductive polymer by polymerization and an oxidizer solution, and is pulled up from each solution to advance the polymerization reaction. These solid electrolyte layers may be formed by a method of applying or discharging a solution containing a polymerizable monomer and an oxidant solution. Moreover, the method of immersing and apply | coating to the mixed solution which mixed the polymerizable monomer solution and the oxidizing agent may be used.

Also, the solid electrolyte layer can be formed by an electrolytic polymerization method used in the field of solid electrolytic capacitors or a method of applying and drying a conductive polymer solution. Furthermore, it is also possible to form a solid electrolyte layer by combining these solid electrolyte layer forming methods.

As described above, thiophene, pyrrole or their derivatives can be suitably used as the polymerizable monomer used for forming the solid electrolyte layer. In particular, the monomer is preferably thiophene or a derivative thereof.

Examples of thiophene derivatives can be exemplified by the following structures: thiophene or its derivatives have higher electrical conductivity and particularly excellent thermal stability than polypyrrole or polyaniline. An excellent solid electrolytic capacitor can be obtained.

X is O or S.
When X is O, A is alkylene or polyoxyalkylene.
When at least one of X is S, A is alkylene, polyoxyalkylene, substituted alkylene, or substituted polyoxyalkylene. Here, the substituent is an alkyl group, an alkenyl group, or an alkoxy group.

Among the thiophene derivatives, 3,4-ethylenedioxythiophene is preferably used.

As an oxidizing agent used for polymerization of a polymerizable monomer, an aqueous solution of ferric paratoluenesulfonate, periodic acid or iodic acid dissolved in ethanol can be used.

Further, as shown in FIG. 1B, a cathode layer composed of a graphite layer and a silver paste layer is sequentially formed on the solid electrolyte layer of the capacitor element piece to form a cathode lead-out portion 123.

When the preparation up to the cathode lead-out portion 123 is completed, the resist protective film previously formed on the anode body is removed, and the aluminum at both ends of the anode body is exposed to form the anode lead-out portion 122 and the capacitor element piece 121. This capacitor element piece 121 has a length of 1.5 mm for the anode lead portions 122 and 122 at both ends, a length of 0.5 mm for the separation layer 124, a length of 6 mm for the cathode lead portion 123, and a width of 5 mm for all the capacitor element pieces. It becomes a piece 121.

As shown in FIG. 2, the capacitor element pieces 121 formed as described above are stacked so that the cathode lead portions 123 overlap and the anode lead portions 122 and 122 form a right angle to each other. Thus, a capacitor element 120 having a cross-shaped top view in which the anode lead-out part 123 and the anode lead-out part 122 are radially arranged in four directions from the cathode lead-out part 123 is formed.

When the capacitor element piece 121 is formed by stacking the capacitor element pieces 121, the size of the cathode lead portion 123 of the capacitor element piece 121 is a rectangle of 5 × 6 mm. It is preferable to overlap the portions so that they protrude from each other by 0.5 mm. When the end portions of the cathode lead-out portion 123 are overlapped so as to protrude by 0.5 mm from each other, the capacitor element 120 is formed in a cross shape when viewed from above, and the cathode lead-out portion 123 is arranged at the center thereof. However, the cathode lead-out portion 123 has a square shape of approximately 6 × 6 mm, and has four corner portions cut out in a size of 0.5 × 0.5 mm. By filling the notched portion with a conductive material, which will be described later, a conductive path that conducts the cathode lead portions 123, 123 of the upper and lower capacitor element pieces 121, 121 is formed.

Thus, the following characteristics can be obtained by stacking capacitor element pieces each having an anode lead portion at both ends and a cathode lead portion at the center in a cross shape in a top view.

(1) By forming the anode terminal at four locations, the current path can be divided into four, and the substantial ESL can be reduced to ¼.
(2) Opposite anode terminal portions are electrically connected inside the capacitor element pieces, and are composed of an opposing anode terminal portion 2 and a cathode terminal portion connected to a cathode lead portion, so that a transmission line structure Can be made to function as a noise filter of a three-pole terminal. When this solid electrolytic capacitor is mounted on a circuit board, an electric signal input from one of the opposing anode terminal portions is filtered, and the electric signal is output to the other anode terminal portion.

In addition, since this transmission line structure intersects and has little mutual influence, the pair of opposite anode terminal portions is used as a noise filter, and the other pair of opposite anode terminal portions is used as an output terminal of a capacitor for transient response. It is also possible to do.

Next, the capacitor element mounting substrate used in the first embodiment of the present invention will be described with reference to FIGS. The mounting substrate 141 is based on an insulating substrate such as a rectangular glass epoxy substrate, and includes an anode terminal portion 142 and a cathode terminal portion 143 on the lower surface, and the upper surface is connected to the anode lead portion and the cathode lead portion of the capacitor element, respectively. The anode conductor 144 and the cathode conductor 145 are provided, and the anode conductor 144 and the anode terminal portion 142 on the upper surface and the back surface are electrically connected to each other.

A cathode conductor joined to the cathode lead portion of the capacitor element is formed in a square shape at the center of the capacitor element mounting surface of the mounting substrate 141, and the anode conductor 144 is disposed so as to surround the cathode conductor 145. . On the other hand, on the mounting surface of the mounting substrate 141, a cathode terminal portion 143 is formed at the center, and four anode terminal portions 142 are arranged so as to surround the cathode terminal portion 143. The anode conductor 144 and the anode terminal portion 142, and the cathode conductor 145 and the cathode terminal portion 143 formed on both surfaces of the mounting substrate 141 are electrically joined through electrodes 148 penetrating the front and back of via holes or through holes, respectively. Yes.

It is preferable to use a glass epoxy substrate having a thickness of about 200 μm from the viewpoint of strength, but a glass epoxy substrate having a thickness of about 80 μm can also be used. The electrodes and conductors formed on the glass epoxy substrate need only have low electrical resistance and can be soldered, and it is preferable to use copper or nickel plated gold conductor. The electrodes and conductors can be formed with a thickness of 3 to 5 μm on one side. In addition, the electrodes and conductors on both surfaces of the mounting substrate 141 and the through holes that electrically connect them can be formed by a method for creating a double-sided printed circuit board that is often used in printed circuit boards. The arrangement of the through holes, the inner diameter, etc. at this time can be arbitrarily set.

In such a mounting board, first, the distance from the anode lead part and cathode lead part of the capacitor element to the anode terminal part and cathode terminal part of the mounting board that is the outlet of the current is only the thickness of the mounting board. The distance can be achieved, and the current path can be shortened. In particular, the thickness of the mounting substrate is preferably about 200 μm, but a thickness of about 80 μm can also be manufactured. Compared to the case where the capacitor element is attached to the lead frame and resin molded, the capacitor The distance from the cathode lead portion of the device to the cathode terminal portion can be made extremely short. Moreover, by forming the anode terminal portion at four locations, the current path can be divided into four, and the substantial ESL can be reduced to ¼. Combined with these two ESL reduction effects, the ESL of the solid electrolytic capacitor can be reduced.

Next, the process of mounting the capacitor element on the mounting board will be described.

As shown in FIG. 5, the capacitor element 120 is mounted on the mounting substrate 141, and the cathode lead-out portion 123 of the capacitor element 120 and the cathode conductor 145 of the mounting substrate are joined by a conductive adhesive. Further, the anode lead part 122 of the capacitor element 120 and the anode conductor 144 are connected. At this time, the anode lead portion 122 of the capacitor element 120 is aluminum, and the wettability with the silver paste or the like is not good, and adhesion with the silver paste may be difficult. In such a case, a connecting member 127 such as a copper material is connected to the anode lead portion 122 of the capacitor element 120 by laser welding, ultrasonic welding, or the like, and the connecting member 127 is made of a conductive material such as silver paste. It is preferable to bond to the anode conductor 144 of the mounting substrate 141 with an adhesive.

Further, by connecting the side surfaces of the cathode lead-out portion 123 of the capacitor element pieces 121 on which the capacitor elements 120 are laminated with the conductive material 149 and further connected to the cathode conductor 145, the capacitor element pieces are stacked and arranged one above the other. The internal resistance between the cathode lead portions 123 and 123 of 121 and 121 can be reduced, and a conductive path to the cathode conductor 145 of the mounting substrate 141 is formed. For this reason, the charge accumulated in the capacitance forming part of the laminated capacitor element can be supplied quickly from anywhere in the four anode terminal parts, so that the solid electrolytic capacitor as a whole has excellent transient response characteristics. A capacitor can be obtained.

Further, the number of capacitor elements mounted on the mounting substrate 141 is not limited to one. When a large capacitance is required, capacitor elements can be further stacked to achieve the required capacitance.

Then, for the purpose of mechanical protection of the capacitor element mounted on the mounting substrate and the shielding from the outside air, the exterior is molded by exterior resin. In addition, you may package an exterior by sticking to a board | substrate using a resin case.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the second embodiment, capacitor element pieces and capacitor elements formed by stacking the capacitor element pieces are the same as those in the first embodiment.
A capacitor element mounting substrate used in the second embodiment will be described with reference to FIGS. The mounting substrate 241 is based on an insulating substrate such as a rectangular glass epoxy substrate, and includes an anode terminal portion 242 and a first cathode terminal portion 243 on a mounting surface that faces a wiring substrate on which a solid electrolytic capacitor is mounted. The surface on which the capacitor element is mounted is provided with an anode conductor 244 and a cathode conductor 245 connected to the anode lead portion and the cathode lead portion of the capacitor element, respectively, and the anode conductor 244, the anode terminal portion 242 and the cathode conductor on each surface. 245 and the first cathode terminal portion 243 are electrically connected.

More specifically, as shown in FIG. 6A, a cathode conductor 245 joined to the cathode lead portion of the capacitor element is formed in a square shape at the center of the surface of the mounting substrate 241 where the capacitor element is mounted. The four anode conductors 244 are arranged on the four sides of the mounting substrate 241 so as to surround the outer periphery of the cathode conductor 245. In addition, auxiliary conductors 247 that are electrically continuous with the cathode conductors 245 are disposed at the four corners of the mounting substrate 241. On the other hand, as shown in FIG. 6B, on the mounting surface of the mounting substrate 241, a first cathode terminal portion 243 having substantially the same size as that of the anode conductor 244 is formed in the central portion. Four anode terminal portions 242 are arranged on the four sides so as to surround the outer periphery of the first cathode terminal portion 243. The second cathode terminal portion 246 is disposed adjacent to the anode terminal portion 242 at the four corners of the mounting surface of the mounting substrate 241. As shown in FIG. 7, the anode conductor 244 and anode terminal portion 242, the cathode conductor 245 and first cathode terminal portion 243, the auxiliary conductor 247 and second cathode terminal portion 246 formed on both surfaces of the mounting substrate 241 are These are electrically connected to each other through conductors 248 penetrating front and back such as via holes or through holes formed substantially perpendicular to the substrate surface of the mounting substrate 241.

The anode conductor 244 and the cathode conductor 245 disposed on the surface of the mounting substrate 241 on which the capacitor element is mounted are conductors corresponding respectively to the anode lead portion and the cathode lead portion of the capacitor element, and match the shape of the capacitor element. It becomes the size and arrangement which can be mounted. When a cross-shaped capacitor element suitable for the shape of the capacitor element as described above is used, the cathode conductor 245 corresponding to the cathode lead portion of the capacitor element is a conductor formed on the mounting substrate 241. Will occupy the largest area. Further, if the first cathode terminal portion 243 connected to the cathode conductor 245 through a through hole or the like is also formed so as to occupy the same area as the cathode conductor 245, the cathode conductor 245, The first cathode terminal portion 243 is arranged at the shortest distance through the through hole, and it is achieved to shorten the current path that is an element of ESL reduction. Therefore, also on the mounting surface of the mounting substrate 241, the area occupied by the first cathode terminal portion 243 is the largest compared to the anode terminal portion 242 and the second cathode terminal portion 246. Further, increasing the area occupied by the first cathode terminal portion 243 also increases the current capacity, and it is possible to flow a large current when outputting the charge accumulated by the capacitor element. By supplying the electric charge required at the time of the transient response with a large current, it is possible to quickly recover the instantaneous voltage drop state.

It is preferable to use a substrate having a thickness of about 200 μm in terms of strength, but an insulating substrate having a thickness of about 80 μm can also be used. The anode terminal portion, the first cathode terminal portion, the second cathode terminal portion, and the conductor formed on the insulating substrate need only have low electrical resistance and can be soldered. It is preferable to use a conductor plated with gold. The electrodes and conductors can be formed with a thickness of 3 to 5 μm on one side. In addition, the anode terminal portion of the mounting substrate 241, the cathode terminal portion and the conductor, and the through holes that electrically connect them can be formed by a method for producing a double-sided wiring board that is often used in printed wiring boards. it can. The arrangement of the through holes, the inner diameter, etc. at this time can be arbitrarily set.

Note that the first cathode terminal portion 243 and the second cathode terminal portion 246 are preferably insulated by a resist layer on the mounting surface of the mounting substrate 241. When the conductive pattern connecting the first cathode terminal portion 243 and the second cathode terminal portion 246 is exposed on the mounting surface of the mounting substrate 241, the first cathode terminal portion 243 and the second cathode terminal portion The distance between the conductive pattern connecting 246 and the anode terminal portion 242 becomes short, and a solder bridge may be generated when soldering on the mounting surface, resulting in a short circuit. Therefore, when a conductive pattern for connecting the first cathode terminal portion 243 and the second cathode terminal portion 246 is formed on the mounting surface of the mounting substrate 241, it is preferable that at least the conductive pattern is covered with a resist layer. .

Further, in order to electrically connect the first cathode terminal portion 243 and the second cathode terminal portion 246, the cathode conductor 245 and the auxiliary conductor 247 are connected to the conductive pattern on the surface on which the capacitor element of the mounting substrate 241 is mounted. It is most preferable that the auxiliary conductor 247 and the second cathode terminal portion 246 are connected by a through hole or the like. Regardless of whether the conductive pattern is formed on the surface on which the capacitor element is mounted or the mounting surface, the characteristics of the solid electrolytic capacitor are not greatly affected. However, if a conductive pattern is formed on the mounting surface, this solid This is because there is a possibility that noise is generated due to electromagnetic coupling with a conductive pattern formed on a wiring board or the like on which an electrolytic capacitor is mounted.

In addition, the anode terminal portion 242 and the second cathode terminal portion 246 of the mounting substrate 241 are preferably formed up to the end of the mounting surface of the mounting substrate 241. If the anode terminal portion 242 and the second cathode terminal portion 246 are formed up to the end of the mounting surface of the mounting substrate 241, when the solid electrolytic capacitor is mounted on the wiring substrate or the like by soldering, the wiring substrate or the like A solder fillet is formed between the conductive pattern, the anode terminal portion 242 and the second cathode terminal portion 246, and visibility of whether or not the soldering connection is surely made is improved. Furthermore, when the anode terminal portion 242 and the second cathode terminal portion 246 are formed from the mounting surface to the side surface of the mounting substrate 241, a solder fillet is formed large, which is preferable.

In such a mounting substrate, first, the distance from the anode lead portion and the cathode lead portion of the capacitor element to the anode terminal portion and the first cathode terminal portion of the mounting substrate, which is the outlet of current, is determined by the thickness of the mounting substrate. This can be achieved by a short distance, and the current path can be shortened. In particular, the thickness of the mounting substrate is preferably about 200 μm, but a thickness of about 80 μm can also be manufactured. Compared to the case where the capacitor element is attached to the lead frame and resin molded, the capacitor The distance from the cathode lead portion of the element to the first cathode terminal portion can be made extremely short. Second, since the anode terminal portion of the mounting substrate is arranged in three directions by the first cathode terminal portion and the second cathode terminal portion, the effect of canceling the induced magnetic fields of the anode and the cathode is large. Third, by forming the anode terminal portion at four locations, the current path can be divided into four, and the substantial ESL can be reduced to ¼.

That is, in the solid electrolytic capacitor of the present invention, a method of shortening the length of the current path as the first element technology for reducing ESL and a magnetic field formed by the current path as the second element technique are separated. Using all the methods of canceling by the magnetic field formed by the current path of the current, and dividing the current path, which is the third elemental technology, into n pieces and reducing the effective ESL to 1 / n, This enhances the effect of reducing the above.

Further, the second cathode terminal portion equivalent in potential to the first cathode terminal portion is formed at the four corners of the mounting surface of the mounting substrate 241, so that the degree of freedom of conduction with the GND line such as the wiring substrate to be mounted is increased. Can also be increased. Further, in the conventional solid electrolytic capacitor having a five-terminal structure, it is difficult to visually confirm whether the first cathode terminal portion is securely soldered. However, the second cathode terminal portion 246 is formed at the four corners. By forming the second cathode terminal portion 246 to the end of the mounting substrate 241, a solder fillet is formed between the conductive pattern of the wiring board to be mounted and the second cathode terminal portion 246. Visibility of surely soldering connection is improved.

Further, as shown in the modification of FIG. 9, the first cathode terminal portion formed on the mounting substrate 241 is not a pattern with the entire surface exposed, but at the center of the first cathode terminal portion 243 formed in a square shape. May be formed in a so-called square shape without forming a conductive pattern and having an insulating region at the center. If the first cathode terminal portion 243 is formed in the shape of a mouth in this way, the current path of the first cathode terminal portion 243 is narrowed and the current is concentrated. In addition, since the first cathode terminal portion where the current is concentrated is disposed so as to be close to the anode terminal portion 242, the effect of canceling the induced magnetic field can be further enhanced, and the overall ESL reduction effect can be achieved. A further improved solid electrolytic capacitor can be realized. In order to form such a first cathode terminal portion 243, a conductive pattern is not formed in advance, and the first cathode terminal portion 243 is formed with a conductive pattern on the entire surface, and the central portion is covered with a resist layer. Thus, the central portion can be an insulating region.

Even when the first cathode terminal portion 243 is formed in such a so-called square shape, the outer peripheral region of the first cathode terminal portion 243 is formed in a region substantially equal to the size of the cathode lead portion of the capacitor element. Thus, the anode and the cathode are arranged closest to each other, and the effect of canceling the induced magnetic field is large and preferable.

In terms of the characteristics of the solid electrolytic capacitor as a single unit, it is preferable that the shape of the first cathode terminal is a square shape as described above, but the pattern arrangement of the substrate on which the solid electrolytic capacitor is mounted In addition, the shape of the first cathode terminal portion can be arbitrarily changed depending on the terminal arrangement of the IC supplied with power by the solid electrolytic capacitor or the amount of electric power required. For example, in FIG. 6, the shape of the first cathode terminal portion 243 is not a perfect square, but an octagonal shape in which square corners are cut.

Next, the process of mounting the capacitor element on the mounting board will be described. Here, an example using the capacitor element 220 similar to the capacitor element 120 described in FIG. 2 used in the first embodiment will be described.

As shown in FIG. 8, the capacitor element 220 is mounted on the mounting substrate 241, and the cathode lead-out portion 223 of the capacitor element 220 and the cathode conductor 245 of the mounting substrate are joined by a conductive adhesive. Further, the anode lead part 222 of the capacitor element 220 and the anode conductor 244 are connected. At this time, the anode lead portion 222 of the capacitor element 220 is aluminum, and the wettability with the silver paste or the like is not good, and there are cases where adhesion with the silver paste is difficult. In such a case, a connecting member 227 such as a copper material is connected to the anode lead portion 222 of the capacitor element 220 by laser welding, ultrasonic welding or the like, and this connecting member 227 is made of a conductive material such as silver paste. It is preferable to join the anode conductor 244 of the mounting substrate 241 with an adhesive.

Further, the number of capacitor elements mounted on the mounting board 241 is not limited to one. When a large capacitance is required, capacitor elements can be further stacked to achieve the required capacitance.

Then, for the purpose of mechanical protection of the capacitor element mounted on the mounting substrate and the shielding from the outside air, the exterior is molded by exterior resin. In addition, you may package an exterior by sticking to a board | substrate using a resin case.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the third embodiment, capacitor element pieces and capacitor elements formed by stacking the capacitor element pieces are the same as those in the first embodiment.
Next, a mounting substrate on which the capacitor element used in the third embodiment is mounted will be described with reference to FIG. The mounting substrate 341 is based on an insulating substrate such as a rectangular glass epoxy substrate, and has an anode terminal portion 342 and a cathode terminal portion 343 on the bottom surface, and is connected to the anode lead portion and the cathode lead portion of the capacitor element on the top surface. The anode conductor 344 and the cathode conductor 345 are connected to each other, and the anode conductor 344 and the anode terminal portion 342 on the top surface and the back surface are electrically connected to each other.

Anode conductors 344 are arranged at the four corners of the capacitor element mounting surface of the mounting substrate 341. In the center portion, a cathode conductor 345 joined to the cathode lead portion of the capacitor element is formed in a square shape. On the other hand, on the mounting surface of the mounting substrate 341, four anode terminal portions 342 are formed at four corners, and a cathode terminal portion 343 is disposed at the center portion. The anode conductor and anode terminal portion, and the cathode conductor and cathode terminal portion formed on both surfaces of the mounting substrate 341 are electrically joined via electrodes 348 penetrating the front and back surfaces of via holes or through holes, respectively.

Further, the cathode terminal portion 343 of the mounting substrate 341 is preferably formed up to the end of the mounting surface of the mounting substrate 341. If the cathode terminal portion is formed up to the end of the mounting surface of the mounting board 341, when the solid electrolytic capacitor is mounted on the printed board or the like by soldering, the conductive pattern of the printed board or the like, the anode terminal part 342 and the cathode A solder fillet is formed between the terminal portion 343 and the visibility of whether or not the solder connection is surely improved. FIG. 12 shows an example in which such a cathode terminal portion 343 is formed up to the end portion of the mounting surface of the mounting substrate 341. The cathode terminal portion 343 formed at the end portion of the mounting substrate only needs to be electrically connected to the cathode terminal portion 343 formed at the center, and even if it has a separated shape on the mounting surface. good.

In such a mounting board, the length of the diagonal line is about 1.4 times the length of the mounting board in the vertical or horizontal dimension. If the transmission line is formed on the diagonal line, a transmission line having a length of about 1.4 times can be theoretically formed compared to the case where the transmission line is formed in parallel to the vertical and horizontal directions of the mounting substrate. However, even if the transmission line is formed, it is necessary to electrically connect the entrance and the exit of the transmission line. Considering the space for forming the anode conductor for connecting this transmission line, the length of the transmission line is 1.1 to 1.3 times the vertical dimension of the mounting substrate.

When the distributed constant circuit is formed on this transmission line, the length of the distributed constant circuit is 1.0 to 1.2 times that in the case where the transmission line parallel to the two sides of the mounting substrate is formed. It is possible to form a distributed constant circuit having a length of.

Here, the transmission line is constituted between the anode lead portions facing each other of the capacitor element, and the distributed constant circuit is constituted by a dielectric layer and a cathode electrode layer (solid electrolyte layer) serving as a capacitance forming portion of the capacitor element. . The length of the transmission line and the length of the distributed constant circuit can be changed depending on the shape and width of the capacitor element, and can be arbitrarily designed in consideration of the required capacitance and transmission line length.

FIG. 11 shows a modification in which the length of the transmission line and the length of the distributed constant circuit are made as long as possible by using the same mounting board. If the anode lead-out portion 322 of the capacitor element is formed in a substantially triangular shape so as to match the corner of the element mounting surface of the mounting substrate, the length of the distributed constant circuit (the cathode electrode layer of the capacitor element (solid electrolyte) The length of the layer) can be made longer.

It is preferable to use a glass epoxy substrate having a thickness of about 200 μm from the viewpoint of strength, but a glass epoxy substrate having a thickness of about 80 μm can also be used. And the conductor formed on a glass epoxy board | substrate should just have a small electrical resistance and can be soldered, and it is preferable to use copper and the conductor which plated gold on nickel. The conductor can be formed with a thickness of 3 to 5 μm on one side. The conductors and electrodes on both sides of the mounting board 341 and the through holes for electrically joining them can be formed by a method for producing a double-sided printed board often used in printed circuit boards. The arrangement of the through holes, the inner diameter, etc. at this time can be arbitrarily set.

When viewed as a solid electrolytic capacitor using such a mounting board, first, the distance from the anode lead part and cathode lead part of the capacitor element to the anode terminal part and cathode terminal part of the mounting board that is the outlet of current Can be achieved by a distance equal to the thickness of the mounting substrate, and the current path can be shortened. In particular, the thickness of the mounting substrate is preferably about 200 μm, and a thickness of about 80 μm can be manufactured. Compared to a solid electrolytic capacitor in which a capacitor element is attached to a lead frame and resin molded, the capacitor The distance from the cathode lead portion of the device to the cathode terminal portion can be made extremely short. Furthermore, by forming the anode terminal portion at four locations, the current path can be divided into four, and the substantial ESL can be reduced to ¼.

In other words, the solid electrolytic capacitor of the present invention uses a method of reducing the length of the current path as much as possible and dividing the current path into n pieces to reduce the effective ESL to 1 / n. The effect of reduction is enhanced.

Furthermore, since the cathode terminal portions 343 are formed on the four sides of the mounting surface of the mounting substrate 341, the degree of freedom of conduction with the GND line of the printed circuit board to be mounted can be increased. Further, in the conventional solid electrolytic capacitor having a five-terminal structure, it is difficult to visually confirm whether the cathode terminal portion is securely soldered, but by forming the cathode terminal portion on four sides, the conductive pattern of the printed circuit board to be mounted A solder fillet is formed between the cathode terminal portion 343 and the like, and the visibility of whether or not the solder connection is surely improved.

Next, the process of mounting the capacitor element on the mounting board will be described. Here, an example using the capacitor element 320 similar to the capacitor element 120 described in the first embodiment and described in FIG. 2 will be described.

As shown in FIG. 10, the capacitor element 320 is mounted on the mounting substrate 341, and the cathode lead-out portion 323 of the capacitor element 320 and the cathode conductor 345 of the mounting substrate are joined by a conductive adhesive. Further, the anode lead portion 322 of the capacitor element 320 and the anode conductor 344 are connected. At this time, the anode lead portion 322 of the capacitor element 320 is aluminum, and the wettability with the silver paste or the like is not good, and adhesion with the silver paste may be difficult. In such a case, a connection member 327 such as a copper material is connected to the anode lead portion 322 of the capacitor element 320 by laser welding, ultrasonic welding, or the like, and the connection member 327 is electrically conductive such as silver paste. It is preferable to join the anode conductor 344 of the mounting substrate 341 with an adhesive.

Further, the number of capacitor elements mounted on the mounting board 341 is not limited to one. When a large capacitance is required, capacitor elements can be further stacked to achieve the required capacitance.

Then, for the purpose of mechanical protection of the capacitor element mounted on the mounting substrate and the shielding from the outside air, the exterior is molded by exterior resin. In addition, you may package an exterior by sticking to a board | substrate using a resin case.

This application is Japanese Patent Application No. 2009-088318 filed on March 31, 2009, Japanese Patent Application No. 2009-124737 filed on May 22, 2009, Japanese Patent Application filed on September 30, 2009. Based on application / application number 2009-228751, the contents of which are incorporated herein by reference.

120 Capacitor Element 121 Capacitor Element Piece 122 Anode Leading Portion 123 Cathode Leading Portion 124 Separation Layer 125 Etching Layer 127 Connecting Member 141 Mounting Board 142 Anode Terminal Portion 143 Cathode Terminal Portion 144 Anode Conductor 145 Cathode Conductor 148 Through Hole (Electrode)
149 Conductive material 220 Capacitor element 222 Anode lead portion 223 Cathode lead portion 227 Connection member 241 Mounting substrate 242 Anode terminal portion 243 First cathode terminal portion 244 Anode conductor 245 Cathode conductor 246 Second cathode terminal portion 247 Auxiliary conductor 248 Through hole (conductor)
320 Capacitor Element 322 Anode Leading Portion 323 Cathode Leading Portion 327 Connection Member 341 Mounting Board 342 Anode Terminal Portion 343 Cathode Terminal Portion 344 Anode Conductor 345 Cathode Conductor 348 Through Hole (Electrode)

Claims (9)

Capacitor element pieces in which both ends of the anode body are anode lead portions and both surfaces of the central portion of the anode body are cathode lead portions, the cathode lead portions overlap with each other, and the anode lead portions are shifted from each other in a substantially perpendicular direction. A solid electrolytic capacitor having a capacitor element laminated on the substrate. The solid electrolytic capacitor according to claim 1, wherein the cathode lead portions on the side surfaces of the laminated capacitor element pieces are connected with a conductive material. In a solid electrolytic capacitor having a capacitor element in which both ends of the anode body are anode lead portions, and a dielectric layer, a solid electrolyte layer, and a cathode lead portion are sequentially formed on the anode body,
A first cathode terminal portion is arranged at the center of the mounting surface facing the wiring board, an anode terminal portion is arranged around the first cathode terminal portion, and a second cathode is adjacent to the anode terminal portion. Solid electrolytic capacitor with terminal. Capacitor elements in which both ends of the anode body are anode extraction portions, and a dielectric layer, a solid electrolyte layer, and a cathode extraction portion are sequentially formed on the anode body,
A surface on which the capacitor element is mounted and a mounting surface facing the wiring board are provided, and on the surface on which the capacitor element is mounted, a conductor corresponding to each of the anode lead portion and the cathode lead portion of the capacitor element is formed, On the mounting surface facing the wiring board, an anode terminal part and a cathode terminal part are formed, and the conductor penetrates the wiring board and is electrically connected to the anode terminal part and the cathode terminal part, respectively. Consisting of a substrate,
On the mounting surface of the mounting substrate, the first cathode terminal portion is arranged at the center thereof, and the anode terminal portions are arranged on the four sides of the mounting surface of the mounting substrate around the first cathode terminal portion, A solid electrolytic capacitor in which second cathode terminal portions are arranged adjacent to the anode terminal portion at four corners of the mounting surface of the mounting substrate. The first cathode terminal portion is formed in a region substantially equal to the size of the cathode lead portion of the capacitor element, and is larger than the anode terminal portion and the second cathode terminal portion. A solid electrolytic capacitor according to any one of the above. The first cathode terminal portion is arranged in a central portion of the mounting surface of the mounting substrate and in a region close to each anode terminal portion, and an insulating region is formed in the central portion of the mounting surface. The solid electrolytic capacitor as described in any one of Claim 5 thru | or 5. A solid electrolytic capacitor comprising a mounting surface that is surface-mounted on a printed circuit board on one surface, a rectangular mounting substrate that has an element mounting surface on which the capacitor element is mounted on the other surface, and a capacitor element,
The mounting board has anode terminal portions at the four corners of the mounting surface and cathode terminal portions at the central portion, an anode conductor connected to the anode terminal portion at the four corners of the device mounting surface, and the cathode terminal at the central portion. The cathode conductors that are connected to the parts are respectively arranged,
In the capacitor element, a capacitance forming portion, a cathode electrode layer, and a cathode lead portion are sequentially stacked at the center of the conductor, and an anode lead portion made of four conductors protruding from the periphery of the cathode lead portion is formed. ,
The anode lead portion of the capacitor element is connected to the anode conductor of the mounting substrate, the cathode lead portion of the capacitor element is connected to the cathode conductor, and a transmission line is formed by the conductor of the capacitor element located at the diagonal of the mounting substrate. Solid electrolytic capacitor with structure. The solid electrolytic capacitor according to claim 7, wherein the capacitor element is made of a rectangular conductor, and a plurality of capacitor element pieces in which the anode lead portion protrudes from both ends of the cathode lead portion are stacked in a cross shape. The solid electrolytic capacitor according to claim 7, wherein the capacitor element is made of a cross-shaped conductor, and the anode lead portion protrudes from the periphery of the cathode lead portion.

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