JP5007677B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multi-terminal solid electrolytic capacitor that is thin, excellent in freedom of component arrangement, and that can be efficiently manufactured, and a method for manufacturing the same.

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-described conventional problems, and an object of the present invention is to provide a multi-terminal solid electrolytic capacitor that is thin, excellent in freedom of component placement, and can be efficiently manufactured, and a method for manufacturing the same. Is to provide.

  In order to achieve the above object, a solid electrolytic capacitor according to one aspect of the present invention is formed by forming a protective layer on at least one surface of a metal plate made of a valve metal and forming a recess on the surface on which the protective layer is formed. An ingot of the metal plate forming the anode part is exposed on the inner surface of the recess, the ingot of the inner surface of the recess is enlarged, an oxide film layer is formed on the surface, and the oxide film layer is formed on the oxide film layer. A solid electrolyte layer is formed, a cathode terminal portion is formed on the solid electrolyte layer, the protective layer around the recess is partially removed, and the metal plate base metal forming the anode drawing means is exposed. A solid piece is formed by forming an anode terminal on the metal plate forming the exposed anode lead-out means, and cutting the metal plate so as to partition the predetermined region including the concave portion and the anode terminal as a unit. Special feature of electrolytic capacitor To.

  In another aspect of the present invention, the above aspect is taken from the viewpoint of a method for producing a solid electrolytic capacitor. A step of forming a protective layer on at least one surface of a metal plate made of a valve metal, and a surface on which the protective layer is formed. Exposing the valve metal ingot to the inner surface of the recess by forming a recess in the surface, expanding the valve metal ingot on the inner surface of the recess, and forming an oxide film layer on the surface; Forming a solid electrolyte layer on the oxide film layer; forming a cathode terminal on the solid electrolyte layer; and partially removing the protective layer on the metal plate around the recess. A step of exposing a metal plate of the metal plate forming the anode lead-out means, a step of forming an anode terminal on the metal plate forming the exposed anode lead-out means, the concave portion, and a plurality of the anode terminals Ward with the area of By cutting a metal plate to, and having the steps of a solid electrolytic capacitor of the pieces, the.

  In this way, the concave portion is exposed on one side of the metal plate provided with the protective layer, the oxide film layer, the solid electrolyte layer, and the cathode terminal are provided, and the anode terminal is provided on the metal plate surface from which a part of the protective layer is removed, By cutting into individual pieces, it becomes possible to manufacture a multi-terminal solid electrolytic capacitor having a thin shape and excellent freedom of component arrangement with excellent efficiency, and characteristics such as transient response are improved.

  In another aspect of the solid electrolytic capacitor of the present invention, a portion of the cathode terminal portion excluding a predetermined external exposed portion that should be exposed to the outside is further covered with an insulating resin.

  In another aspect of the present invention, the above aspect is taken from the viewpoint of a method for producing a solid electrolytic capacitor, and further, a portion of the cathode terminal portion excluding a predetermined external exposed portion to be exposed to the outside, And a step of coating by injecting an insulating resin.

  Thus, by covering the periphery of the cathode terminal portion with the insulating resin, the insulation between the anode and the cathode can be enhanced, and by covering a part of the cathode external electrode constituting the cathode terminal portion, the cathode The bonding strength of the external electrode can be increased.

  As described above, according to the present invention, a metal plate in which a concave portion is exposed on one side of a metal plate provided with a protective layer, an oxide film layer, a solid electrolyte layer, and a cathode terminal are provided, and a part of the protective layer is removed. By providing an anode terminal on the surface and cutting it into individual pieces, it is possible to manufacture a multi-terminal type solid electrolytic capacitor that is thin, compact, and has excellent flexibility in component placement, with excellent efficiency and characteristics such as transient response. 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 processes A to J, and a solid electrolytic capacitor manufactured as such. Here, each process step is shown in the cross-sectional views of FIGS. 1 and 2, 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 (FIG. 1 (1)). The metal type is preferably aluminum and the thickness is generally considered to be about 200 to 800 microns, but the metal type and thickness can be changed as appropriate. For example, valve action metals such as tantalum, niobium, and titanium can be used in addition to aluminum.

B. Formation of Protective Layer Then, the protective layer 2 is formed on at least one surface of the metal plate 1 (FIG. 1 (2)). The protective layer 2 does not need to cover the entire surface of the metal plate 1, and the protective layer 2 may be provided with a window portion for subsequent processing. 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.

C. Formation of recess Next, by forming recesses 3 at predetermined intervals on the surface on which the protective layer 2 is formed, the metal bar 1 forming the anode part is exposed on the inner surface of the recess 3 (FIG. 1 (3) )). Here, as a means for forming the recess 3, cutting of the metal plate 1 is suitable. When the protective layer 2 has a window portion, the window portion may be pressed to form a recess, or the window portion may be etched to form a recess. When the concave portion 3 is formed by the above, the concave portion can be efficiently formed by simultaneously performing the etching process of “D. Etching and formation of oxide film” described later.

D. 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 on the surface of the recess subjected to the surface expansion process by anodic oxidation (FIG. 1 (4) ). Here, well-known means can be used for etching and anodic oxidation.

E. Formation of Solid Electrolyte Layer A solid electrolyte layer 5 is formed on the oxide film layer 4 (FIG. 1 (5)). 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.

F. Formation of the cathode terminal portion And, by providing a cathode external electrode on the solid electrolyte layer 5 through a graphite (Gr) layer and a silver paste layer (indicated by reference numeral 6 together) (FIG. 1 (6)), The cathode terminal portion 7 is formed (FIG. 2 (7)). 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.

  In addition, as the cathode external electrode, it is preferable to connect a metal plate material such as copper with a conductive adhesive, but the plate material is a flat plate, and a protrusion is provided on the flat plate, and this protrusion is used as a cathode external terminal. Also good. Further, the cathode external electrode may be configured by performing copper plating on the silver paste layer. However, a distance for insulation, that is, a gap is provided between the cathode external electrode and the protective layer on the same surface.

  When a plate material having a plurality of protrusions formed on a flat plate is used as a cathode external electrode, and the plurality of protrusions are used as cathode external terminals, the cathode terminal portion 7 is a multi-terminal electrode structure derived as a plurality of cathode terminal portions 7. It becomes.

  It should be noted that a flat plate material may be used as the cathode external electrode, and the protrusions may be formed after the flat plate material is bonded to the silver paste layer. The protrusions can be formed by a method similar to “I. Formation of anode terminal” described later to form a so-called bump electrode.

G. Coating with Insulating Resin Next, a portion of the cathode terminal portion 7 excluding a predetermined external exposed portion that should be exposed to the outside is covered by injecting insulating resin 8 (FIG. 2 (8)). Here, the externally exposed portion is, for example, the upper surface or the protruding portion of the cathode terminal portion 7, and the portion excluding the externally exposed portion is, for example, between the side end surface and the protective layer 2. Moreover, as the insulating resin 8, a thermosetting epoxy resin is suitable.

  The insulating resin 8 enters the gap between the concave portion and the cathode external electrode, so that the insulation between the anode and the cathode can be enhanced, and the bonding strength of the cathode external electrode can be increased by covering a part of the cathode external electrode. Can be increased. For example, if a plate material having a plurality of projections formed on a flat plate is used as the cathode external electrode and the upper surface of the plate material is covered with the insulating resin 8 so that only the projections are exposed, the upper surface of the cathode external electrode is integrated with the metal plate. Thus, the bonding strength of the cathode external terminal can be increased.

H. Removal of protective layer Further, in order to achieve electrical connection with the anode terminal, the protective layer 2 of the metal plate 1 around the recess 3 is partially removed to expose the metal plate and form an anode lead-out means It is set as the exposed part 9 (FIG. 2 (9)). At this time, the protective layer may only be exposed, or even the metal plate may be cut, and the cutting depth can be adjusted as appropriate in relation to the height of the anode terminal to be formed later. Thus, the state which removed the protective layer 2 of the metal plate 1 partially, and provided the exposed part 9 is shown in the perspective view of FIG.3 (2).

I. Formation of Anode Terminal Then, the anode terminal 10 is formed on the exposed portion 9 that forms the anode drawing means exposed as described above (FIG. 2 (10)). The anode terminal 10 uses a so-called bump electrode, a gold bump obtained by cutting a gold wire by thermocompression bonding, and a ball grid array in which solder balls are bonded onto a copper plating to form ball-shaped terminals in a grid array ( BGA) and the like can be freely selected. Thus, the state which provided the anode terminal 10 is shown in the perspective view of FIG.3 (3).

  Such a bump electrode can be formed in a rectangular region having a width of about 300 μm, and the region of the anode terminal portion that does not contribute to the capacitance of the solid electrolytic capacitor can be made extremely small.

  Furthermore, the number of anode terminals 10 formed is arbitrary, and when a plurality of anode terminals 10 are formed on one side (in FIG. 3 (3), three anode terminals are formed on each side), a plurality of anode terminals 10 are formed. A multi-terminal electrode structure derived as the anode terminal 10 is obtained.

J. et al. Cutting into pieces Finally, the metal plate is cut so as to partition a predetermined region including the concave portion and the anode terminal, in this embodiment, a region including the anode terminal disposed so as to sandwich the concave portion 3. Thus, an individual solid electrolytic capacitor is obtained (FIG. 2 (11)). At this time, the thickness of the cathode external electrode and the height of the anode terminal are set or adjusted in advance in each of the upstream steps A to I so that the heights of the anode and cathode external terminals are in the same plane position. deep. Prior to cutting, the periphery 10 of the anode terminal may be reinforced and fixed with resin 11 as shown in the perspective view of FIG.

(2) Operation and effect As described above, the concave portion is exposed on one side of the metal plate provided with the protective layer, the oxide film layer, the solid electrolyte layer, and the cathode terminal are provided, and the protective layer is partially removed to extract the anode. Produces a multi-terminal solid electrolytic capacitor with excellent efficiency by providing an anode terminal on the metal plate that forms the means and cutting it into individual pieces. It becomes possible.

  In addition, the cathode terminal part is formed in the vicinity of the interface between the oxide film, which is a capacitor holding part as a capacitor, and the solid electrolyte layer, and even devices such as circuit patterns and LSIs connected to the capacitor holding part and the cathode terminal part. , And the current routing path inside the capacitor is shortened, so that transient response to power supply voltage instability 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 the anode terminal, the height of the anode and cathode external terminals are set to the same plane position, and the entire plane including the external terminals is made to be the same plane shape without waste. Electrolytic capacitors can be stacked in the vertical direction, such as between the substrate and the back of the substrate, and direct wiring using bump electrodes can be performed on the LSI that is the current supply target, further improving transient response. Is done.

  Furthermore, the anode terminal of the solid electrolytic capacitor so that the current path is shortened by being installed close to the LSI as described above, and the circuit pattern to be mounted and the terminal position of a device such as LSI are matched. Since the lead-out position and the number of cathode terminals can be set arbitrarily, an optimum electrode lead structure can be realized for a circuit pattern to be mounted and a device such as an LSI to be connected.

(3) Other Embodiments The present invention is not limited to the above-described embodiment, and includes the following embodiments 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, it is possible to omit covering a portion of the cathode terminal portion excluding the externally exposed portion that should be exposed to the outside with an insulating resin.

Sectional drawing which shows the manufacturing method (first half) of the solid electrolytic capacitor in embodiment of this invention. Sectional drawing which shows the manufacturing method (latter half) of the solid electrolytic capacitor in embodiment of this invention. The perspective view which shows the manufacturing method (part) of the solid electrolytic capacitor in 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 9 ... Exposed part 10 ... Anode terminal 11 ... Resin

Claims (4)

Forming a protective layer on at least one side of the metal plate made of valve metal,
By forming a recess on the surface on which the protective layer is formed, the metal plate forming the anode part on the inner surface of the recess is exposed,
Surface expansion of the metal on the inner surface of the recess, forming an oxide film layer on the surface,
Forming a solid electrolyte layer on the oxide film layer;
Forming a cathode terminal on the solid electrolyte layer;
A part of the protective layer around the recess is partially removed to expose the metal sheet metal that forms the anode lead means;
Form an anode terminal on the metal plate ingot that forms the exposed anode lead means,
A solid electrolytic capacitor, characterized in that an individual solid electrolytic capacitor is obtained by cutting a metal plate so as to partition a predetermined region including the concave portion and the anode terminal as a unit.   2. The solid electrolytic capacitor according to claim 1, wherein a portion of the cathode terminal portion excluding a predetermined external exposed portion to be exposed to the outside is covered with an insulating resin. Forming a protective layer on at least one side of a metal plate made of a valve metal;
Exposing the metal sheet metal to form an anode on the inner surface of the recess by forming a recess in the surface on which the protective layer is formed;
Expanding the surface of the inner surface of the recess, and forming an oxide film layer on the surface;
Forming a solid electrolyte layer on the oxide film layer;
Forming a cathode terminal on the solid electrolyte layer;
A step of partially removing the protective layer of the metal plate around the recess to expose the metal plate ingot to form the anode lead means;
Forming an anode terminal on the metal plate forming the exposed anode lead means;
Cutting the metal plate so as to partition the concave portion and a predetermined region including the plurality of anode terminals as a unit, thereby forming a solid electrolytic capacitor as a piece;
A method for producing a solid electrolytic capacitor, comprising:   4. The solid electrolytic capacitor according to claim 3, further comprising a step of covering a portion of the cathode terminal portion excluding a predetermined external exposed portion to be exposed to the outside by injecting an insulating resin. Production method.

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