JP5120026B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multi-terminal solid electrolytic capacitor that is excellent in manufacturing accuracy and bonding strength in addition to characteristics, and that is thin and has a high degree of freedom in component placement, 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 can be made smaller and operated at high speed. 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.

  In this regard, the conventional solid electrolytic capacitor as described above has a structure in which a cathode body is sandwiched between two pieces or an anode terminal is attached, and there is a limit to the 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 has been proposed in order to solve the above-mentioned problems, and its purpose is excellent in manufacturing accuracy, bonding strength and safety in addition to characteristics, and in particular, it is thin and small and has a component arrangement. An object of the present invention is to provide a multi-terminal solid electrolytic capacitor having a high degree of freedom and a method for manufacturing the same.

  In order to achieve the above object, a solid electrolytic capacitor according to an aspect of the present invention includes forming a plurality of groove-shaped first holes not penetrating the metal plate on one surface of a metal plate made of a valve metal. The metal opposite to the surface on which the first hole is formed is formed on the surface on which the first hole is formed by filling the first hole and forming a first protective layer covering the surface. A plurality of groove-shaped second holes each communicating with the first hole are formed on the surface of the plate, and the second hole is filled in the surface on which the second hole is formed and Forming a second protective layer covering the surface, and forming recesses at predetermined intervals on the surface of the metal plate on which the second protective layer between the adjacent second holes is formed; The valve metal ingot is exposed on the inner surface of the recess, the valve metal ingot on the inner surface of the recess is expanded, and an oxide film is formed on the surface. Forming a solid electrolyte layer on the oxide film layer in the recess, forming a cathode terminal portion on the solid electrolyte layer, and providing an anode terminal portion; The metal plate ingot is exposed by partially removing the second protective layer, the anode terminal portion is formed on the exposed metal plate, and the first and second portions communicate with each other. The solid protective capacitor is obtained by cutting the first and second protective layers at the hole portion.

  Another aspect of the present invention is a method of manufacturing a solid electrolytic capacitor in which the above aspect is captured from the viewpoint of the method, wherein a groove-shaped first hole that does not penetrate the metal plate is provided on one surface of the metal plate made of a valve metal. A step of forming a plurality, a step of filling the first hole with respect to the surface on which the first hole is formed, and forming a first protective layer covering the surface, and the first Forming a plurality of groove-shaped second holes respectively communicating with the first holes on the surface of the metal plate opposite to the surface on which the holes are formed; and on the surface on which the second holes are formed. On the other hand, a step of forming a second protective layer filling the second hole and covering the surface, and the metal on which the second protective layer between the adjacent second holes is formed Forming recesses at predetermined intervals on the surface of the plate, exposing the metal base metal to the inner surface of the recesses, and Expanding the surface metal of the valve metal on the inner surface, forming an oxide film layer on the surface, forming a solid electrolyte layer on the oxide film layer in the recess, A step of forming a cathode terminal portion on the solid electrolyte layer, and in order to provide an anode terminal portion, the base metal of the metal plate is exposed by partially removing the second protective layer around the recess. Cutting the first and second protective layers at a step, a step of forming the anode terminal portion on the bare metal plate, and a portion of the first and second holes communicating with each other. And a step of forming a solid electrolytic capacitor as a single piece.

  In the aspect as described above, the first hole is formed on one surface of the metal plate, the first protective layer is formed on the surface so as to fill the first hole, and the first hole is formed. A second hole is formed on the surface opposite to the surface on which the second layer is formed, and a second protective layer is formed on the surface opposite to fill the second hole. Then, a base metal is exposed by forming a concave portion on the surface of the metal plate on which the second protective layer is formed, and an oxide film layer, a solid electrolyte layer, a cathode terminal are provided in the concave portion, and both sides of the concave portion are provided. An anode terminal portion is provided on the substrate and cut at the positions of the first and second holes.

  This makes it possible to cover the side surfaces of the individual solid electrolytic capacitors with a protective layer using an insulating resin or the like. That is, since the side surface of the solid electrolytic capacitor is covered with the protective layer, the bonding strength of the metal plate and the anode terminal portion is increased, and the safety is further improved. Moreover, since the hole filled with the protective layer is cut when the individual pieces are formed, the anode terminal portion is not damaged, and a highly accurate solid electrolytic capacitor can be provided.

  Moreover, since the protective layer is formed on both surfaces of the metal plate, the solid electrolytic capacitor can be significantly reduced in thickness and size as compared with the case where the reinforcing layer is formed on one surface. Specifically, when a reinforcing layer is formed on one side of a metal plate, a hole that penetrates the metal plate from the opposite side of the reinforcing layer but does not penetrate the reinforcing layer is cut, and the surface on which the hole is formed is cut. On the other hand, a protective layer is formed. Therefore, it is necessary to provide the reinforcing layer with a certain thickness so as not to penetrate the reinforcing layer when cutting the hole.

  In contrast, according to the present invention, the first and second holes corresponding to and communicated with each other at the cutting position are provided, and the protective layer is formed on both surfaces of the metal plate. It is possible to make the protective layer thin. Thereby, size reduction of a solid electrolytic capacitor is realizable.

  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.

  As described above, according to the present invention, in addition to the characteristics, the manufacturing accuracy, the bonding strength and the safety are excellent, and in particular, the multi-terminal type solid electrolytic capacitor which is thin and small and has a high degree of freedom of component placement, and the manufacturing thereof. It is to provide a method.

  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 by the following steps A to L, 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 the 1st hole And the groove-shaped 1st hole 2 which does not penetrate the metal plate 1 is formed by cutting one surface of the metal plate 1 (FIG. 1 (2)). The shape of the hole 2 may be a continuous groove shape, or may be a plurality of holes intermittent at a constant pitch (length and interval).

C. Formation of a 1st protective layer Then, the 1st protective layer 3 is formed with respect to the surface in which the 1st hole 2 of the metal plate 1 was formed (FIG. 1 (3)). As a result, the first hole 2 is filled with the protective layer 3. The first protective layer 3 may be a resin coating layer such as a so-called resist, an anodic oxide film, or the like, and may be a layer that is not corroded by an etching solution during the surface enlargement process by etching described later. For example, the type and formation method can be freely selected. Of course, an insulating resin such as a thermosetting epoxy resin can also be used.

D. Formation of the second hole Then, the groove-shaped second hole 4 is formed by cutting the surface of the metal plate 1 opposite to the surface on which the first hole 2 is formed (FIG. 1 (4)). ). Here, the second hole 4 is cut to correspond to the position of the first hole 2 so as to reach the first protective layer 3 filled in the first hole 2 from the opposite side. It is formed. Therefore, the second hole 4 and the first hole 2 are configured to communicate with each other. The shape of the second hole 4 may be a continuous groove shape as in the first hole 2, or may be a plurality of holes intermittent at a constant pitch (length and interval). Neither the relationship with the first hole 2 nor the size of the shape is specified.

E. Formation of the 2nd protective layer Then, the 2nd protective layer 5 is formed with respect to the surface in which the 2nd hole 4 of the metal plate 1 was formed (FIG. 1 (5)). As a result, the second protective layer 5 is filled in the second hole 4 formed so as to reach the first protective layer.

  The second protective layer 5 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. As the second protective layer 5, as in the case of the first protective layer 3, an anodic oxide film may be formed in addition to a resin coating layer such as a so-called resist. In addition, as long as it is a layer that is not corroded by the etching solution, the type and means of formation can be freely selected. Of course, it is also possible to use an insulating resin such as a thermosetting epoxy resin.

F. Formation of recesses Subsequently, by forming recesses 6 at predetermined intervals on the surface of the metal plate 1 on which the second protective layer 5 between the second holes 4 is formed, the metal plate 1 is formed on the inner surface of the recesses 6. The bare metal is exposed (FIG. 1 (6)). Here, as a means for forming the recess 6, cutting of the metal plate 1 is suitable. In addition, when the window part is formed in the 2nd protective layer 5, the recessed part 6 is formed by press-working the window part part, or the recessed part 6 is formed by etching the window part part. In particular, when the recess 6 is formed by etching, the recess 6 can be efficiently formed by simultaneously performing the etching process of “G. Etching and formation of oxide film” described later.

G. Etching and Formation of Oxide Film Thereafter, the bare metal exposed on the inner surface of the concave portion 6 is subjected to surface expansion treatment by etching, and further anodized on the surface of the concave portion 6 subjected to the surface expansion treatment, thereby forming the oxide film layer 7 (FIG. 2 (7)). Here, it is possible to use known means for etching and anodizing.

H. Formation of Solid Electrolyte Layer and Cathode Terminal Portion A solid electrolyte layer 8 is formed on the oxide film layer 7 (FIG. 2 (8)). Here, as the solid electrolyte layer 8, 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 10 is formed by providing a cathode external electrode on the solid electrolyte layer 8 through a graphite (Gr) layer and a silver paste layer (indicated by reference numeral 9 together) (FIG. 2 ( 8)). The graphite (Gr) layer and the silver paste layer 9 itself may be the same as the known technique in a 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 formed by applying copper plating on the silver paste layer. However, there is no insulation between the cathode external electrode as the cathode terminal portion 10 and the second protective layer 5. It is necessary to provide a distance, that is, a gap.

  When a plate material having a plurality of protrusions formed on a flat plate is used as the cathode external electrode, and the plurality of protrusions are used as cathode external terminals, the cathode terminal portion 10 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.

I. Coating with Insulating Resin Next, a portion of the cathode terminal portion 10 excluding a predetermined externally exposed portion that should be exposed to the outside is covered by injecting the insulating resin 11 (FIG. 2 (9)). . As the insulating resin 11, a thermosetting epoxy resin is suitable.

  Here, for example, when the cathode terminal portion 10 has a protrusion on a flat plate as shown in FIG. 2 (9), the externally exposed portion corresponds to this protrusion, and the portion excluding the externally exposed portion is And the gap between the upper surface portion and the side end surface of the flat plate and the second protective layer 5. On the other hand, when the cathode terminal portion 10 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 the side end surface or the second protective layer 5. Such as the above gap.

  Insulating resin 11 is injected into a portion excluding a predetermined externally exposed portion that should be exposed to the outside of cathode terminal portion 10, thereby making it possible to improve the insulation between the anode and the cathode. 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 11 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.

J. et al. Partial removal of the protective layer Further, in order to achieve electrical connection with the anode terminal portion 13 described later, the second protective layer 5 of the metal plate 1 around the recess 6 is partially removed to remove the metal plate 1. The bare metal is exposed to form an exposed portion 12 for providing the anode terminal portion 13 (FIG. 2 (10)). At this time, the second protective layer 5 may be exposed only, or the metal plate may be cut, and the cutting depth can be adjusted as appropriate in relation to the height of the anode terminal portion 13 to be formed later. It is.

K. Formation of Anode Terminal Part Then, the anode terminal part 13 is formed on the exposed part 12 from which the second protective layer 5 has been removed as described above (FIG. 2 (11)). This anode terminal portion 13 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 on a copper plating to form ball-shaped terminals in a grid arrangement. (BGA) or the like can be freely selected.

  Such a bump electrode can form an electrode in a rectangular region having a width of about 300 μm, and the region of the anode terminal portion 13 that does not contribute to the capacitance of the solid electrolytic capacitor can be made extremely small. . Furthermore, the number of anode terminal portions 13 formed is arbitrary, and when a plurality of anode terminal portions 13 are formed on one side, a multi-terminal electrode structure derived as the plurality of anode terminal portions 13 is obtained.

L. Cutting into individual pieces Finally, the first and second protective layers 3 and 5 filled in the holes 2 and 4 are cut (cut) at the first hole 2 and the second hole 4, and By cutting each of the cathode terminal portions 10 as a unit, individual solid electrolytic capacitors are obtained (FIG. 2 (12)). That is, it cuts so that the predetermined area | region containing the recessed part 6 and the anode terminal part 13, and the area | region containing the anode terminal part 13 arrange | positioned facing this so that the recessed part 6 may be pinched | interposed in this embodiment.

(2) Operational effects As described above, the first hole is formed on one surface of the metal plate, and the first protective layer is formed on the surface so as to fill the first hole. A second hole is formed on a surface opposite to the surface on which the first hole is formed, and a second protective layer is formed on the opposite surface so as to fill the second hole. Then, a base metal is exposed by forming a concave portion on the surface of the metal plate on which the second protective layer is formed, and an oxide film layer, a solid electrolyte layer, a cathode terminal are provided in the concave portion, and both sides of the concave portion are provided. An anode terminal portion is provided on the substrate and cut at the positions of the first and second holes.

  This makes it possible to cover the side surfaces of the individual solid electrolytic capacitors with a protective layer using an insulating resin or the like. That is, since the side surface of the solid electrolytic capacitor is covered with the protective layer, the bonding strength of the metal plate and the anode terminal portion is increased, and the safety is further improved. Moreover, since the hole filled with the protective layer is cut when the individual pieces are formed, the anode terminal portion is not damaged, and a highly accurate solid electrolytic capacitor can be provided.

  Moreover, since the protective layer is formed on both surfaces of the metal plate, the solid electrolytic capacitor can be significantly reduced in thickness and size as compared with the case where the reinforcing layer is formed on one surface. Specifically, when a reinforcing layer is formed on one side of a metal plate, a hole that penetrates the metal plate from the opposite side of the reinforcing layer but does not penetrate the reinforcing layer is cut, and the surface on which the hole is formed is cut. On the other hand, a protective layer is formed. Therefore, it is necessary to provide the reinforcing layer with a certain thickness so as not to penetrate the reinforcing layer when cutting the hole.

  On the other hand, in the present embodiment, the first and second holes corresponding to and communicated with each other at the cutting position are provided, and the protective layer is formed on both surfaces of the metal plate, so that the reinforcing layer has a thickness to avoid penetration. As compared with the case, the protective layer to be formed can be made thinner. Thereby, size reduction of a solid electrolytic capacitor is realizable.

  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, 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 10 excluding the externally exposed portion that should be exposed to the outside with the insulating resin 11.

  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. For example, in the said embodiment, although the recessed part 6 is formed in the metal plate 1 in which the 2nd protective layer 5 was formed, it is not limited to this, On the surface in which the 1st protective layer 3 was formed On the other hand, the recess 6 may be formed.

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 ... 1st hole 3 ... 1st protective layer 4 ... 2nd hole 5 ... 2nd protective layer 6 ... Concave 7 ... Oxide film layer 8 ... Solid electrolyte layer 9 ... Graphite (Gr) layer And silver paste layer 10 ... cathode terminal part 11 ... insulating resin 12 ... exposed part 13 ... anode terminal part

Claims (2)

A plurality of groove-shaped first holes that do not penetrate the metal plate are formed on one surface of the metal plate made of the valve metal,
Forming a first protective layer that fills the first hole and covers the surface with respect to the surface on which the first hole is formed;
Forming a plurality of groove-shaped second holes respectively communicating with the first holes on the surface of the metal plate opposite to the surface on which the first holes are formed;
Forming a second protective layer that fills the second hole and covers the surface with respect to the surface on which the second hole is formed;
By forming recesses at predetermined intervals on the surface of the metal plate on which the second protective layer between adjacent second holes is formed, the metal base metal of the valve metal is exposed on the inner surface of the recesses. ,
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 plate is exposed by partially removing the second protective layer around the recess,
Forming the anode terminal portion on the bare metal plate exposed,
A solid electrolytic capacitor, wherein the first and second protective layers are cut at the portions of the first and second holes communicating with each other to form individual solid electrolytic capacitors. Forming a plurality of groove-shaped first holes not penetrating the metal plate on one surface of the metal plate made of valve metal;
Forming a first protective layer that fills the first hole and covers the surface with respect to the surface on which the first hole is formed;
Forming a plurality of groove-shaped second holes respectively communicating with the first holes on the surface of the metal plate opposite to the surface on which the first holes are formed;
Forming a second protective layer that fills the second hole and covers the surface with respect to the surface on which the second hole is formed;
By forming recesses at predetermined intervals on the surface of the metal plate on which the second protective layer between the adjacent second holes is formed, the metal base metal of the valve metal is exposed on the inner surface of the recesses. Process,
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 second protective layer around the recess,
Forming the anode terminal portion on the bare metal plate exposed;
Cutting the first and second protective layers at the portions of the first and second holes respectively communicating with each other to form individual solid electrolytic capacitors;
The manufacturing method of the solid electrolytic capacitor characterized by including this.

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