JP5120025B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multi-terminal solid electrolytic capacitor that is thin and has a high degree of freedom in component arrangement, and has excellent manufacturing accuracy and bonding strength in addition to characteristics, and a manufacturing method thereof.

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 Documents 1 and 2 show an example of a conventional solid electrolytic capacitor and a manufacturing method thereof. 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 individual pieces. Two cathode bodies are sandwiched and an anode terminal is attached.
JP-A-3-284818 JP-A-4-5813 JP-A-2-301118

  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.

  In addition, in a method of manufacturing a solid electrolytic capacitor in which a flat solid electrolyte layer or an insulating layer having openings is laminated on a substrate to draw out each electrode, the substrate is divided into comb-like rows and columns by cutting. Although there are proposals to improve the manufacturing efficiency (for example, refer to Patent Document 3, especially FIG. 1 (B)), the substrate in which only one end is connected is unstable and the accuracy and efficiency of processing are limited. .

  The present invention has been proposed in order to solve the above-described problems, and its purpose is thin and small and has a high degree of freedom in component placement, in addition to characteristics, manufacturing accuracy and bonding strength, An object of the present invention is to provide a multi-terminal solid electrolytic capacitor excellent in safety and a method for manufacturing the same.

  In order to achieve the above object, the solid electrolytic capacitor according to one aspect of the present invention is formed by forming a reinforcing layer on one surface of a metal plate made of a valve metal and cutting the surface opposite to the reinforcing layer. Forming a plurality of groove-shaped holes that penetrate the metal plate but do not penetrate the reinforcing layer, and form a protective layer that covers the surface while filling the hole with respect to the surface opposite to the reinforcing layer, By forming recesses at predetermined intervals on the surface of the metal plate on which the protective layer between adjacent holes is formed, a valve metal ingot is exposed on the inner surface of the recess, and the valve on the inner surface of the recess Metal base metal is subjected to surface expansion treatment, an oxide film layer is formed on the surface, a solid electrolyte layer is formed on the oxide film layer in the recess, and a cathode terminal is formed on the solid electrolyte layer. In order to form a part and provide an anode terminal part, And removing the metal plate to expose the metal plate, to form the anode terminal portion on the exposed metal plate, and at the hole portion, the metal plate, the reinforcing layer, and the protection By cutting the layer, a solid electrolytic capacitor of individual pieces is obtained.

  Another aspect of the present invention is a method of manufacturing a solid electrolytic capacitor in which the above aspect is grasped from the viewpoint of the method, the step of forming a reinforcing layer on one side of a metal plate made of a valve metal, and the opposite of the reinforcing layer Cutting a surface to form a plurality of groove-shaped holes that penetrate the metal plate but not the reinforcing layer, and fill the holes on the surface opposite to the reinforcing layer. A step of forming a protective layer covering the surface, and forming a concave portion at a predetermined interval on the surface of the metal plate on which the protective layer between the adjacent holes is formed, thereby forming a valve metal on the inner surface of the concave portion. A step of exposing the bare metal, a step of expanding the bare metal of the valve metal on the inner surface of the concave portion, forming an oxide film layer on the surface, and on the oxide film layer in the concave portion, A step of forming a solid electrolyte layer, and a cathode end on the solid electrolyte layer A step of forming a metal plate, a step of exposing the metal plate in the metal plate by partially removing the protective layer around the concave portion, and a step of exposing the metal plate in the exposed metal plate. Forming the anode terminal portion thereon, and cutting the metal plate, the reinforcing layer, and the protective layer at the hole portion to form a solid electrolytic capacitor in pieces. Features.

  In the above embodiment, a metal base is exposed by forming a recess on the surface of the metal plate opposite to the surface on which the reinforcing layer is formed, and an oxide film layer, a solid electrolyte layer, and a cathode terminal are provided in the recess. An anode terminal portion was provided on both sides of the recess, and a protective layer was injected into a hole formed in the metal plate and cut at the position of the hole, thereby using an insulating resin or the like on the side surface of the individual solid electrolytic capacitor It becomes possible to coat with a protective layer.

  Thereby, since the side surface of the solid electrolytic capacitor is covered with the protective layer, the bonding strength of the metal plate, the reinforcing layer, and the anode terminal portion is increased, and the safety is further improved. Moreover, since the hole into which the protective layer is injected is cut when forming the individual pieces, the anode terminal portion is not damaged, and a highly accurate solid electrolytic capacitor can be provided.

  In addition, it is a capacity | capacitance holding part as a capacitor | condenser by forming a recessed part in the metal plate single side | surface which provided the protective layer, exposing a base metal, and having provided the oxide film layer, the solid electrolyte layer, and the cathode terminal in the recessed part. The cathode terminal part is formed in the vicinity of the interface between the oxide film and the solid electrolyte layer. The distance between the capacitor holding part and the cathode terminal part to the circuit pattern or LSI device is short, and the current inside the capacitor Since the routing route is shortened, the transient response to the unstable power supply voltage is improved. In addition, by forming a reinforcing layer on the metal plate and making the hole through the metal plate but not through the reinforcing layer, the metal plate is more stable with the reinforcing layer than in the case of cutting in a comb shape as in the past. Processing accuracy and efficiency can be maintained.

  Furthermore, since the conventional sandwich structure is not necessary, it is possible to reduce the thickness and the size. In particular, the external electrode of the anode terminal portion and the cathode terminal portion are close to each other, and the effect of canceling the induced magnetic field generated when current flows through the external electrode and the cathode terminal portion of the anode terminal portion is increased. ESL can be reduced.

  Also, by covering the periphery of the cathode terminal with an insulating resin, the insulating resin enters the gap between the recess and the cathode external electrode to improve the insulation between the anode and the cathode, and the cathode terminal is made up of the insulating resin. By covering a part of the cathode external electrode, the bonding strength of the cathode external electrode can be increased.

  As described above, according to the present invention, there are provided a multi-terminal solid electrolytic capacitor that is thin and small, has a high degree of freedom in component arrangement, has excellent manufacturing accuracy and bonding strength in addition to characteristics, and a method for manufacturing the same. Is possible.

  Next, the best mode for carrying out the present invention will be described below with reference to FIGS. In addition, the description common to the contents already described in the background art and problems will be omitted as appropriate.

(1) Configuration The present embodiment relates to a method for manufacturing a solid electrolytic capacitor according to the following steps A to K, and a solid electrolytic capacitor manufactured as such. Here, each process step is shown in the cross-sectional views of FIGS.

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)). This metal plate is long, and FIG. 1 and FIG. 2 are cross-sectional views in which the depth direction is the longitudinal direction toward the figure. The metal plate 1 is preferably made of aluminum and generally has a thickness of about 200 to 800 microns, but the type and thickness of the metal 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 Reinforcing Layer Then, the reinforcing layer 2 is formed on one surface of the metal plate 1 (FIG. 1 (2)). The reinforcing layer 2 can be freely selected by attaching an insulating resin material such as an epoxy material, which is a reinforcing member, or by applying an insulating resin, a SUS material, or the like. From the viewpoint of ensuring insulation, it is preferable to use an insulating resin.

C. Formation of hole Subsequently, the metal plate 1 is cut from the surface opposite to the surface of the reinforcing layer 2 to form a groove-shaped hole 3 that penetrates the metal plate 1 but does not penetrate the reinforcing layer 2 (FIG. 1 (3)). The shape of the hole 3 may be a continuous groove shape, or may be a plurality of holes intermittent at a constant pitch (length and interval). Further, in any case, the reinforcing layer 2 is not connected in a comb-like shape, when viewed from the longitudinal direction of the groove-shaped hole, at least a part close to both ends.

D. Formation of the protective layer Then, the protective layer 4 is formed on the surface of the metal plate 1 on which the hole 3 opposite to the reinforcing layer 2 is formed (FIG. 1 (4)). The protective layer 4 does not need to cover the entire surface of the metal plate 1 and may be formed with a window for processing to form a concave portion to be described later. Further, as the protective layer 4, in addition to a resin coating layer such as a so-called resist, an anodized film may be formed. If the layer is not corroded by an etching solution during the surface enlargement process by etching described later, The formation method and the like can be freely selected.

E. Formation of recesses Subsequently, by forming recesses 5 at predetermined intervals on the surface of the metal plate 1 on which the protective layer 4 between the holes 3 is formed, the metal of the metal plate 1 is exposed on the inner surface of the recesses 5. (FIG. 1 (5)). Here, as a means for forming the recess 5, cutting of the metal plate 1 is suitable. In addition, when the window part is formed in the protective layer 4, the recessed part 5 may be formed by press-working the window part, or the recessed part 5 may be formed by etching the window part. In the case where the concave portion 5 is formed by etching, the concave portion can be efficiently formed by simultaneously performing the etching process of “F. Etching and formation of oxide film” described later.

F. Etching and Formation of Oxide Film Thereafter, the bare metal exposed on the inner surface of the concave portion 5 is subjected to surface expansion treatment by etching, and further, an oxide film layer 6 is formed by anodizing the surface of the concave portion subjected to the surface expansion treatment (FIG. 1). (6)). Here, it is possible to use known means for etching and anodizing.

G. Formation of Solid Electrolyte Layer and Cathode Terminal Portion A solid electrolyte layer 7 is formed on the oxide film layer 6 (FIG. 2 (7)). Here, as the solid electrolyte layer 7, a conductive polymer is suitable, 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.

  Subsequently, a cathode terminal portion 9 is formed on the solid electrolyte layer 7 by providing a cathode external electrode through a graphite (Gr) layer and a silver paste layer (indicated by reference numeral 8 together) (FIG. 2 ( 7)). The graphite (Gr) layer and the silver paste layer itself may be the same as the publicly known technique in the solid electrolytic capacitor.

  In addition, as the cathode external electrode, it is preferable to connect a metal plate material such as copper with a conductive adhesive, and the plate material may be a flat plate or a projection on the flat plate so that the projection serves as a cathode external terminal. Also good. The cathode external electrode can be configured by copper plating on the silver paste layer, but the distance between the cathode external electrode as the cathode terminal portion 9 and the protective layer 4 is an insulation distance. That is, it is necessary to provide a gap.

  When a plate material having a plurality of projections formed on a flat plate is used as the cathode external electrode and the plurality of projections are used as cathode external terminals, the cathode terminal portion 9 is a multi-terminal electrode derived as a plurality of cathode terminals. It becomes a structure.

  Alternatively, a flat plate material may be used as the cathode external electrode, and the protrusion may be formed after the flat plate material is bonded to the silver paste layer. The bumps are formed by using 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) or the like can be freely selected.

H. Coating with Insulating Resin Next, a portion of the cathode terminal portion 9 excluding a predetermined externally exposed portion that should be exposed to the outside is covered by injecting the insulating resin 10 (FIG. 2 (8)). . As the insulating resin 10, a thermosetting epoxy resin is suitable.

  Here, for example, when the cathode terminal portion 9 has a protrusion on the flat plate as shown in FIG. 2 (8), the externally exposed portion corresponds to this protrusion, and the portion excluding the externally exposed portion is And the above-mentioned gap between the upper surface portion and the side end surface of the flat plate and the protective layer 4. On the other hand, when the cathode terminal portion 9 is a flat plate having no protrusion, the externally exposed portion is the upper surface of the flat plate, and the portion excluding the externally exposed portion is between the side end surface and the protective layer 4. Such as a gap.

  The insulating resin 10 is injected into a portion excluding a predetermined external exposed portion that should be exposed to the outside of the cathode terminal portion 9, whereby the insulation between the anode and the cathode can be improved. It becomes possible to improve the bonding strength of the electrode. That is, for example, if a plate material having a plurality of protrusions 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 10 so that only the protrusions are exposed, the upper surface of the cathode external electrode is a metal plate. And the bonding strength of the cathode external terminal can be increased.

I. Partial removal of the protective layer Further, in order to achieve electrical connection with the anode terminal portion 12 to be described later, the metal layer 1 is removed by partially removing the protective layer 4 of the metal plate 1 around the recess 5. An exposed portion 11 for exposing and providing the anode terminal portion 12 is formed (FIG. 2 (9)). At this time, the protective layer 4 may only be exposed, or even a metal plate may be cut, and the cutting depth can be appropriately adjusted in relation to the height of the anode terminal portion 12 to be formed later.

J. et al. Formation of Anode Terminal Part Then, the anode terminal part 12 is formed on the exposed part 11 that forms the exposed anode lead means as described above (FIG. 2 (10)). The anode terminal portion 12 uses a so-called bump electrode, a gold grid obtained by cutting a gold wire by thermocompression bonding, and a ball grid array in which solder balls are bonded on a copper plating to form ball-shaped terminals in a grid array. (BGA) or the like can be freely selected.

  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 12 that does not contribute to the capacitance of the solid electrolytic capacitor can be made extremely small. . Furthermore, the number of anode terminal portions 12 formed is arbitrary, and when a plurality of anode terminal portions 12 are formed on one side, a multi-terminal electrode structure led out as a plurality of anode terminal portions 12 is obtained.

K. Cutting into individual pieces Finally, the reinforcing layer 2 and the protective layer 4 are cut (cut) at the portion of the hole 3, and the individual cathode terminal portions 9 are cut to form individual solid electrolytic capacitors and (FIG. 2 (11)). That is, it cuts so that the predetermined area | region containing the recessed part 5 and the anode terminal part 12, and the area | region containing the anode terminal part 12 arrange | positioned facing this so that the recessed part 5 may be pinched | interposed in this embodiment.

(2) Operational effects As described above, a metal base is exposed by forming a concave portion on the surface of the metal plate opposite to the surface on which the reinforcing layer is formed, and an oxide film layer, a solid electrolyte layer, a cathode terminal are formed in the concave portion. In addition, an anode terminal portion is provided on both sides of the recess, and a protective layer is injected into a hole formed in the metal plate and cut at the position of the hole, so that the side surface of the individual solid electrolytic capacitor is insulated with resin, etc. It becomes possible to coat with a protective layer using.

  Thereby, since the side surface of the solid electrolytic capacitor is covered with the protective layer, the bonding strength of the metal plate, the reinforcing layer, and the anode terminal portion is increased, and the safety is further improved. Moreover, since the hole into which the protective layer is injected is cut when forming the individual pieces, the anode terminal portion is not damaged, and a highly accurate solid electrolytic capacitor can be provided.

  In addition, it is a capacity | capacitance holding part as a capacitor | condenser by forming a recessed part in the metal plate single side | surface which provided the protective layer, exposing a base metal, and having provided the oxide film layer, the solid electrolyte layer, and the cathode terminal in the recessed part. The cathode terminal part is formed in the vicinity of the interface between the oxide film and the solid electrolyte layer. The distance between the capacitor holding part and the cathode terminal part to the circuit pattern or LSI device is short, and the current inside the capacitor Since the routing route is shortened, the transient response to the unstable power supply voltage is improved. In addition, by forming a reinforcing layer on the metal plate and making the hole through the metal plate but not through the reinforcing layer, the metal plate is more stable with the reinforcing layer than in the case of cutting in a comb shape as in the past. Processing accuracy and efficiency can be maintained.

  In addition, since the conventional sandwich structure is not required, the anode terminal portion is formed directly on the exposed portion of the metal plate of the solid electrolytic capacitor, so that the anode does not contribute to the capacitance of the solid electrolytic capacitor. The region where the terminal portion is provided can be made small, and downsizing is realized. In particular, the external electrode of the anode terminal portion and the cathode terminal portion are close to each other, and the effect of canceling the induced magnetic field generated when current flows through the external electrode and the cathode terminal portion of the anode terminal portion is increased. ESL can be reduced.

  Further, in this embodiment, by covering the periphery of the cathode terminal portion with an insulating resin, the insulating resin enters the gap between the concave portion and the cathode external electrode to improve the insulation between the anode and the cathode. By covering a part of the cathode external electrode constituting the cathode terminal portion, the bonding strength of the cathode external electrode can be increased.

(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 possible to omit covering the portion of the cathode terminal portion 9 excluding the externally exposed portion that should be exposed to the outside with the insulating resin 10. In addition, 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.

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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal plate 2 ... Reinforcement layer 3 ... Hole 4 ... Protective layer 5 ... Recess 6 ... Oxide film layer 7 ... Solid electrolyte layer 8 ... Graphite (Gr) layer and silver paste layer 9 ... Cathode terminal part 10 ... Insulating resin 11 ... Exposed part 12 ... Anode terminal part

Claims (2)

A reinforcing layer is formed on one side of a metal plate made of valve metal,
By cutting from the surface opposite to the reinforcing layer, a plurality of groove-shaped holes that penetrate the metal plate but do not penetrate the reinforcing layer are formed.
Forming a protective layer that fills the hole and covers the surface against the surface opposite to the reinforcing layer;
By forming a recess at a predetermined interval on the surface of the metal plate on which the protective layer between the adjacent holes is formed, the valve metal ingot is exposed on the inner surface of the recess,
Surface expansion of the valve metal ingot 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 in the recess,
Forming a cathode terminal on the solid electrolyte layer;
In order to provide the anode terminal portion, the metal layer bare metal is exposed by partially removing the protective layer around the recess,
Forming the anode terminal portion on the bare metal plate exposed,
A solid electrolytic capacitor, wherein the metal plate, the reinforcing layer, and the protective layer are cut at the hole portion to form an individual solid electrolytic capacitor. Forming a reinforcing layer on one side of a metal plate made of a valve metal;
Cutting a surface opposite to the reinforcing layer to form a plurality of groove-shaped holes that penetrate the metal plate but do not penetrate the reinforcing layer;
Forming a protective layer that fills the hole and covers the surface against the surface opposite to the reinforcing layer;
A step of exposing a valve metal ingot to the inner surface of the recess by forming recesses at predetermined intervals on the surface of the metal plate on which the protective layer between the adjacent holes is formed;
A step of expanding the surface metal of the valve metal 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 in the recess;
Forming a cathode terminal on the solid electrolyte layer;
In order to provide the anode terminal portion, the step of exposing the metal base metal by partially removing the protective layer around the recess, and
Forming the anode terminal portion on the bare metal plate exposed;
Cutting the metal plate, the reinforcing layer and the protective layer at the hole portion to form a solid electrolytic capacitor as a piece;
The manufacturing method of the solid electrolytic capacitor characterized by including this.

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