JP5206008B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multi-terminal solid electrolytic capacitor and a method for manufacturing the same, which are thin and excellent in freedom of component arrangement, and can be manufactured particularly efficiently by a simple process.

At present, various capacitors are used in various electronic circuit fields, and as one of them, solid electrolytic capacitors having a small equivalent series resistance (ESR) and excellent frequency characteristics are widely used. Patent Document 1 shows an example of a conventional solid electrolytic capacitor and a method for manufacturing the same. In this example, a solid electrolyte layer or the like is provided in a recess provided in a metal plate serving as an anode body, and is cut into pieces. And sandwiching the cathode body and attaching the anode terminal.
JP-A-3-284818

  However, in recent years, in the field of digital equipment such as personal computers, multi-terminal type solid electrolytic capacitors have been demanded from the viewpoint of improving characteristics such as low ESL (equivalent series inductance), and the equipment has been adapted to downsizing and high speed operation. Combined with the demand for excellent transient response, there is a need for a solid electrolytic capacitor that is thinner and has a high degree of freedom in component placement. Furthermore, there is a great demand for further improvement in production efficiency from the viewpoint of meeting increasing demand and costs.

  In this regard, the conventional solid electrolytic capacitor as described above has a structure in which a cathode body is sandwiched between two pieces and an anode terminal is attached, and there is a limit to improvement in manufacturing efficiency and reduction in size. Also, in the conventional solid electrolytic capacitor as described above, due to size and shape restrictions, it is essential to mount it on the board at a position shifted in the horizontal direction from the LSI that is the current supply target. There is a limit to the improvement, and from this point, an increase in the degree of freedom in component arrangement has been desired.

  The present invention solves the above-mentioned conventional problems, and its object is to provide a multi-terminal type solid electrolysis that is thin, excellent in freedom of component arrangement, and can be manufactured particularly efficiently by a simple process. It is to provide a capacitor and a manufacturing method thereof.

In order to achieve the above object, a solid electrolytic capacitor according to an aspect of the present invention includes a concave portion formed on the surface of a metal plate made of a valve metal, and an oxide film layer, a solid electrolyte layer, and a cathode terminal portion formed on the inner surface of the concave portion. The upper surface of the cathode terminal portion is sequentially formed so as to be the same flat surface as the surface of the metal plate, and the upper surface of the cathode terminal portion and the upper surface of the metal plate surface ingot around the cathode terminal portion. A gap is provided therebetween, the cathode terminal portion is formed so as not to contact the inner peripheral surface of the concave portion, the metal plate surface metal for drawing out the anode, and the cathode terminal portion are covered, and the metal plate Insulating the surface metal and the cathode terminal part with each other, and forming an insulating resin layer exposing the metal plate surface metal and the cathode terminal part, respectively, the metal plate surface metal and the cathode Each exposed part of the terminal Characterized in that the formation of the terminal portions.

Another aspect of the present invention is to capture the above aspect from the viewpoint of a method. In the method of manufacturing a solid electrolytic capacitor, a step of forming a recess on a metal plate surface made of a valve metal, and an oxide film on the inner surface of the recess A layer, a solid electrolyte layer, and a cathode terminal portion are sequentially formed such that the upper surface of the cathode terminal portion is the same flat surface as the surface of the metal plate , the upper surface of the cathode terminal portion, and the cathode terminal portion A gap is provided between the upper surface of the surrounding metal plate surface metal, the cathode terminal portion is formed so as not to contact the inner peripheral surface of the recess, and the metal plate surface metal that pulls out the anode, Forming an insulating resin layer that covers the metal plate surface metal and the cathode terminal part and exposes part of the metal plate surface metal and the cathode terminal part. And the metal plate surface metal A step of forming an external terminal portion on each exposed portion of the cathode terminal portion, and cutting the metal plate so as to divide each set of the external terminal portions of the positive and negative electrodes as a unit. And a step of forming a capacitor.

As described above, the cathode terminal is provided together with the oxide film layer and the solid electrolyte layer in the concave portion of the metal plate, and is covered with the insulating resin together with the surface of the surrounding metal plate from which the anode is drawn. This insulating resin is intended to insulate the cathode and anode from each other, and to provide an exposed portion (exposed hole) that exposes each part of the anode and cathode, and to form external terminals with gold bumps, solder balls, etc. And cut into pieces. In this way, by integrating the elements and terminals of the solid electrolytic capacitor on one side of the metal plate, the multi-terminal type solid that has a short current path, excellent transient response, thinness, and excellent flexibility in component placement Electrolytic capacitors can be manufactured with excellent efficiency, and furthermore, the manufacturing efficiency can be further improved by forming the insulating coatings and terminals of the positive and negative electrodes together by a simple process. Further, as described above, the cathode terminal portion is formed so that the upper surface of the cathode terminal portion is the same flat surface as the surface of the metal plate, so that an external terminal is formed using gold bumps, solder balls, or the like. In addition, since the external terminals have the same height, the external terminals are arranged on the same plane when the solid electrolytic capacitor is mounted on a substrate or the like. This can improve the manufacturing efficiency because the conditions for forming the external terminals can be made constant.

  According to another aspect of the present invention, in the method for manufacturing a solid electrolytic capacitor described above, in the step of forming the insulating resin layer, the base metal and the cathode terminal are formed by using an insulating resin as a pattern except for the exposed portion. And covering the portion.

  In this manner, by forming the insulating resin layer by printing a pattern in which the exposed portion is removed in advance, a process of peeling the exposed portion is not necessary, and further excellent manufacturing efficiency can be realized.

  According to another aspect of the present invention, in the method for manufacturing a solid electrolytic capacitor described above, the step of forming the insulating resin layer may include a step of covering the entire surface of the base metal and the cathode terminal portion with the insulating resin. And a second step of removing a portion corresponding to the exposed portion of the coating layer.

  In this way, once the entire surface of the metal plate base metal and the cathode terminal portion is covered and the exposed hole portion is removed by peeling or the like, it is not necessary to prepare a print pattern or the like in advance, and the covering state and dimensions are different. It is possible to respond flexibly to varieties.

  As described above, according to the present invention, it is possible to provide a multi-terminal type solid electrolytic capacitor and a method for manufacturing the same, which are thin and excellent in freedom of component arrangement, and can be manufactured particularly efficiently by a simple process. Characteristics such as sex are also improved.

Next, the best mode for carrying out the present invention will be described with reference to the drawings. In addition, the premise common to the content already demonstrated by the background art and the subject is abbreviate | omitted suitably.
(1) Configuration The present embodiment relates to a method for manufacturing a solid electrolytic capacitor by the following steps A to H, and a solid electrolytic capacitor manufactured as such. Here, each process step is shown in the cross-sectional view of FIG. 1, and a part of the process is shown in the perspective view of FIG.

A. Preparation of Metal Plate First, a metal plate 1 made of a valve metal, that is, a valve action metal is prepared, and a protective layer 2 is formed on at least one surface of the metal plate 1 (FIG. 1 (1)). Here, the metal type is desirably aluminum, and the thickness is generally considered to be about 200 to 800 microns, but the metal type and thickness can be appropriately changed. For example, valve action metals such as tantalum, niobium, and titanium can be used in addition to aluminum.

  Moreover, about the protective layer 2, it is not necessary to cover the whole surface of the metal plate 1, and the window part for subsequent processing may be formed. In addition to the resin coating layer, the protective layer 2 may be formed with an anodized film or the like, as long as it is a layer that is not corroded by the etchant during the surface expansion treatment by etching, which will be described later. Etc. can be freely selected.

B. Formation of the concave portion Next, the concave portions 3 are formed at predetermined intervals on the surface on which the protective layer 2 is formed, thereby exposing the metal plate 1 forming the anode portion on the inner surface of the concave portion 3 (FIG. 1 (2). )). Here, as a means for forming the recess 3, cutting of the metal plate 1 is suitable. In the case where a window is formed in the protective layer 2, the recess may be formed by pressing or etching the portion of the window, particularly when the recess 3 is formed by etching. By simultaneously performing the etching process of “C. Etching and formation of oxide film”, the recesses can be formed efficiently.

C. Etching and Formation of Oxide Film Thereafter, the metal on the inner surface of the recess 3 is subjected to a surface expansion process by etching, and an oxide film layer 4 is formed by anodic oxidation on the surface of the recess subjected to the surface expansion process (FIG. 1 (3)) ). Here, well-known means can be used for etching and anodic oxidation.

D. Formation of Solid Electrolyte Layer A solid electrolyte layer 5 is formed on the oxide film layer 4 (FIG. 1 (4)). Here, as the solid electrolyte layer 5, a conductive polymer is preferable, and such a conductive polymer layer is formed by a known technique such as chemical polymerization or electrolytic polymerization based on thiophene, pyrrole, or the like. do it.

E. Formation of Cathode Terminal Portion A graphite (Gr) layer and a silver paste layer (indicated by reference numeral 6 together) are formed on the solid electrolyte layer 5 (FIG. 1 (5)), and a cathode external electrode Is provided to form the cathode terminal portion 7 (FIG. 1 (6)). The graphite (Gr) layer and the silver paste layer itself may be the same as the known technology in a solid electrolytic capacitor. The state in which the cathode terminal portion 7 is formed on the metal plate 1 having the protective layer 2 is shown in the perspective view of FIG. Shown in the figure.

  Further, the cathode external electrode may be configured by performing copper plating on the silver paste layer, but it is preferable to connect a flat plate material made of a metal such as copper with a conductive adhesive. is there. In any case, the upper surface of FIG. 1 serving as the external terminal portion of the cathode external electrode is provided with an insulating distance, that is, a gap, between the upper surface of the surrounding metal plate 1 and the upper surface is made of metal. It forms so that the same flat surface as the upper surface of the board 1 or a substantially identical surface may be comprised. The protective layer 2 shown in FIGS. 1 (1) to 1 (5) is removed (FIG. 1 (6)).

F. Formation of Insulating Resin Layer Next, the surface (upper surface) of the metal plate 1 from which the anode is drawn out and the cathode terminal portion 7 are covered with the insulating resin, and the metal plate surface metal and the cathode terminal portion are mutually connected. Further, an insulating resin layer 8 is formed in which a part of each of the anode and the cathode is exposed through the exposure hole 9 (FIG. 2 (3)). Further, the portion exposed by the insulating resin layer 8 is a predetermined external electrode forming portion that should form an external terminal portion to be an external electrode of the positive and negative electrodes, and the insulating resin constituting the insulating resin layer 8 includes a resist, Thermosetting epoxy resins are preferred.

  The insulating resin of the insulating resin layer 8 enters the gap between the concave portion and the cathode external electrode, thereby improving the insulation between the anode and the cathode and covering a substantial portion of the cathode external electrode. By integrating the upper surface with the surrounding metal plate surface, the bonding strength of the cathode external terminal can be increased.

  Here, as an aspect of forming the insulating resin layer 8 having the exposed holes 9, at least the following two may be mentioned. A 1st aspect coat | covers the said base metal and the cathode terminal part 7 with an insulating resin by making the part except the exposed hole 9 into a pattern as the insulating resin layer 8. FIG.

  In the second mode, a coating layer is formed over the entire surface of the base metal and the cathode terminal portion 7 by applying an insulating resin or the like (FIG. 2 (2)). The insulating resin layer 8 is formed by using each predetermined portion of the metal plate as an external electrode forming portion, that is, by removing a portion corresponding to the exposed hole 9 (FIG. 2 (3)). For example, a predetermined portion corresponding to the exposure hole 9 is masked, an insulating resin is applied, and the masking portion is removed to expose the external electrode forming portions, that is, the exposed portions 11 and 71.

G. Formation of External Electrode Terminals External terminal portions 21 and 27 are respectively formed on the metal plate surface metal and the exposed portions 11 and 71 of the cathode terminal portion 7 (FIG. 2 (5)). Each of these external terminal portions 21 and 27 uses a so-called bump electrode. In addition to a gold bump obtained by cutting a gold wire by thermocompression bonding, a solder ball is bonded onto a copper plating 20 (FIG. 2 (4)) to form a ball shape. A ball grid array (BGA) in which terminals are formed in a lattice arrangement can be freely selected.

  In addition, when copper plating 20 is performed in advance in order to ensure the adhesion of solder (FIG. 2 (4)), the copper plating 20 may be applied only to the exposed portion 11 which is a metal plate ingot portion such as aluminum. Although it is good, copper plating may be performed together with the exposed portion 71 of the cathode terminal portion 7 such as copper (FIG. 2 (4)), thereby simplifying the work process.

  The bump electrodes as described above can be formed in a rectangular region having a width of about 300 μm, and the regions of the negative and positive electrode external terminal portions 21 and 27 that do not contribute to the capacitance of the solid electrolytic capacitor are extremely small. It can be. Furthermore, the number of external terminal portions 21 and 27 formed on each pole is arbitrary. For example, in the example of FIG. 2 (5), each concave portion is sandwiched between three anode terminal portions 21 at both ends. A multi-terminal electrode structure of nine cathode terminal portions 27 is formed.

H. Cutting into pieces Finally, the metal plate 1 is cut so as to divide a region including the cathode external terminal portion 27 on the concave portion and the anode external terminal portion 21 disposed so as to face each other. Thus, a solid electrolytic capacitor is obtained (FIG. 2 (5)). At this time, in the upstream processes A to G, the thickness of the cathode external electrode and the external terminal portion of each of the positive and negative electrodes are adjusted so that the heights of the external terminal portions 21 and 27 of the anode and the cathode are in the same plane position. Height or the like is set or adjusted in advance.

(2) Effects As described above, in the present embodiment, the cathode terminal is provided together with the oxide film layer and the solid electrolyte layer in the concave portion of the metal plate, and the metal plate is covered with the insulating resin together with the surface of the surrounding metal plate. In this insulating resin, the cathode and the anode are insulated from each other, and exposed holes are provided to expose each part of the anode and the cathode, and after forming external terminals with gold bumps, solder balls, etc. on each exposed part, Cut into pieces.

  In this way, by integrating each element of the solid electrolytic capacitor and a large number of electrode terminals on one side of the metal plate, the current path is short, excellent in transient response, thin, and multi-terminal excellent in freedom of component placement Type solid electrolytic capacitors can be manufactured with excellent efficiency, and further, the manufacturing efficiency is further improved by forming the insulating coatings of the positive and negative electrodes and a large number of terminals together by a simple process.

  In the present embodiment, the cathode terminal portion is formed in the vicinity of the interface between the oxide film, which is a capacitor holding portion as a capacitor, and the solid electrolyte layer, and the circuit pattern connected to the capacitor holding portion and the cathode terminal portion Since the distance to a device such as an LSI is short and the current routing path inside the capacitor is shortened, the transient response to instability of the power supply voltage is improved.

  In particular, since the conventional sandwich structure is not required, the thickness can be reduced and the so-called bump electrode can be used to reduce the size, and the mounting area can be reduced to about 5 mm square. In addition, by controlling the thickness of the cathode external electrode and the height of each external terminal part, the height of each pole external terminal part is unified at the same plane position, so that the whole is made the same plane shape without waste. The degree of freedom of layout and wiring is further increased, such as by placing the solid electrolytic capacitors vertically in the vertical direction, such as between the substrate and the back surface of the substrate, with respect to the LSI that is the current supply target, and transient response is improved. It is further improved.

  In addition, the anode terminal and cathode of the solid electrolytic capacitor should be installed close to the LSI as described above to shorten the current path and match the circuit pattern to be mounted and the terminal position of the device such as LSI. Since the lead-out position and the number of terminals can be set arbitrarily, an optimum electrode lead-out structure can be realized for a circuit pattern to be mounted and a device such as an LSI to be connected.

  In particular, in the present embodiment, if the insulating resin layer is formed by printing a pattern in which the exposed hole portion is removed in advance, a process of peeling the exposed hole portion is not necessary, and further excellent manufacturing efficiency can be realized. Become. On the other hand, if the insulating resin layer is formed by once covering the entire surface of the metal plate ingot and the cathode terminal part and then removing the exposed hole part by peeling or the like, it is not necessary to prepare in advance such as a print pattern, It is possible to adapt flexibly to a variety of products with different coating conditions and dimensions.

(3) Other Embodiments The present invention is not limited to the above-described embodiment, but includes the following examples and other embodiments. For example, it is needless to say that the specific types of materials, processing methods, shapes and structures shown in the drawings are merely examples, and can be appropriately changed. For example, the number of horizontal and vertical arrangements of solid electrolytic capacitors manufactured on a metal plate is arbitrary, FIG. 1 shows an example of three columns or three rows, and FIG. 2 shows an example of eight in one column. There is no problem. Further, the arrangement of the external electrodes and the position of cutting as a solid electrolytic capacitor piece are not limited to the specific examples given above, and can be changed as appropriate. For example, as shown in FIG. 3, it is good also as a solid electrolytic capacitor of a piece cut | disconnected so that it may have a some recessed part.

Sectional drawing which shows the manufacturing method (first half) of the solid electrolytic capacitor in embodiment of this invention. The perspective view ((1) and (2)) and top view ((3)-(5)) which show the manufacturing method (part) of the solid electrolytic capacitor in embodiment of this invention. The top view which shows the manufacturing method (part) of the solid electrolytic capacitor in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal plate 2 ... Protective layer 3 ... Recessed part 4 ... Oxide film layer 5 ... Solid electrolyte layer 7 ... Cathode terminal part 8 ... Insulating resin layer 9 ... Exposed hole 11, 71 ... Exposed part 20 ... Copper plating 21, 27 ... External Terminal section

Claims (4)

Forming a recess on the surface of the metal plate made of valve metal,
An oxide film layer, a solid electrolyte layer, and a cathode terminal portion are sequentially formed on the inner surface of the recess so that the upper surface of the cathode terminal portion is the same flat surface as the surface of the metal plate,
A gap is provided between the upper surface of the cathode terminal portion and the upper surface of the metal plate surface metal around the cathode terminal portion, and the cathode terminal portion is formed so as not to contact the inner peripheral surface of the recess. ,
The metal plate surface metal and the cathode terminal are drawn out, and the metal plate surface metal and the cathode terminal are insulated from each other, and the metal plate surface and the cathode terminal Forming an insulating resin layer that exposes a part of each part,
An external terminal portion is formed on each exposed portion of the metal plate surface metal and the cathode terminal portion. Forming a recess on a metal plate surface made of a valve metal;
Sequentially forming an oxide film layer, a solid electrolyte layer, and a cathode terminal portion on the inner surface of the recess so that the upper surface of the cathode terminal portion is the same flat surface as the surface of the metal plate;
A gap is provided between the upper surface of the cathode terminal portion and the upper surface of the metal plate surface metal around the cathode terminal portion, and the cathode terminal portion is formed so as not to contact the inner peripheral surface of the recess. ,
The metal plate surface metal and the cathode terminal are drawn out, and the metal plate surface metal and the cathode terminal are insulated from each other, and the metal plate surface and the cathode terminal Forming an insulating resin layer exposing a part of the part;
Forming an external terminal portion on each exposed portion of the metal plate surface metal and the cathode terminal portion; and
Cutting the metal plate so as to divide each set of the external terminal portions of the yin and yang poles as a unit, thereby forming a solid electrolytic capacitor as a piece;
The manufacturing method of the solid electrolytic capacitor characterized by including this. In the step of forming the insulating resin layer,
The method for manufacturing a solid electrolytic capacitor according to claim 2 , wherein the base metal and the cathode terminal portion are covered with an insulating resin using a portion excluding the exposed portion as a pattern. The step of forming the insulating resin layer includes
A first step of forming a coating layer with the insulating resin over the entire surface of the metal base and the cathode terminal portion;
A second step of removing a portion corresponding to the exposed portion of the coating layer;
The manufacturing method of the solid electrolytic capacitor of Claim 2 characterized by the above-mentioned.

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