Chip type solid electrolytic capacitor, terminals, and method for manufacturing them

The present invention relates to a solid electrolytic capacitor, and more particularly to a structure of a chip-type solid electrolytic capacitor, terminals used therein, and a method for manufacturing the terminals.

Conventionally, solid electrolytic capacitors using tantalum, niobium, etc. as valve acting metals are small in size, have a large capacitance, have excellent frequency characteristics, and are widely used in CPU power supply circuits and the like.

FIG. 8 is a cross-sectional view of a conventional chip-type solid electrolytic capacitor when mounted on a substrate. Reference numeral 1 denotes a capacitor element, and this capacitor element 1 forms a porous anode body by molding and sintering a powder made of a valve acting metal in which an anode lead-out wire 2 is embedded so as to lead out one end of the anode body. A dielectric oxide film is formed by a method known to the above, and an electrolyte layer and a cathode layer (above, omitted in the figure) are sequentially formed on the surface thereof.

Further, the anode lead wire 2 derived from the capacitor element 1 is transferred from the lead wire joint 6b at the tip of the upright portion 6c to the anode terminal 6 composed of the substrate mounting surface portion 6d having an exposed surface on the substrate mounting surface via the upright portion 6c. Electrically connected and fixed, connected to the cathode terminal 5 consisting of the upright portion 5c planted from the substrate mounting surface portion 5d having an exposed surface on the substrate mounting surface via the conductive adhesive 3 to the cathode layer of the capacitor element 1. It is fixed, and the outer resin 4 is covered with an insulating resin so as to cover the entire connection portion and the capacitor element 1, and the outer resin 4 is formed into a desired external size by a known method such as dicing, and is a chip-type electrolytic solid. A capacitor is configured.

Since the chip-type solid electrolytic capacitor has a simple connection structure between the capacitor element 1 and the cathode terminal 5 and the anode terminal 6, the storage volumetric efficiency of the capacitor element 1 with respect to the exterior resin 4 can be improved. In recent years, it has greatly contributed to the progress of miniaturization and thinning of chip-type solid electrolytic capacitors required for further lightness, thinness, shortness and miniaturization in small mobile devices such as mobile phones. Many similar structures have been proposed.

However, in the above-mentioned conventional chip type solid electrolytic capacitor, since the terminal structure is simple, the coupling force between the exterior resin 4 and the cathode terminal 5 and the anode terminal 6 is weak, and it is large at the time of mounting on the substrate 11 or after mounting. When mechanical or thermal stress is applied, cracks 12 occur at the interface between the cathode terminal 5 and the anode terminal 6 and the exterior resin 4, which adversely affects the electrical characteristics and reliability, or in the worst case, There is a problem that the terminal and the exterior resin 4 are separated.

<patcit num="1"><text>JP-A-55-86111</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2001-126958</text></patcit><patcit num="3"><text>JP-A-2002-43175</text></patcit><patcit num="4"><text>Japanese Unexamined Patent Publication No. 2001-358037</text></patcit><patcit num="5"><text>Japanese Unexamined Patent Publication No. 2001-358038</text></patcit><patcit num="6"><text>Japanese Unexamined Patent Publication No. 2001-358041</text></patcit><patcit num="7"><text>Japanese Unexamined Patent Publication No. 2002-170744</text></patcit>

<p> An object of the present invention is to provide a small and large-capacity chip-type solid electrolytic capacitor, a terminal used therein, and a method for manufacturing the same, without weakening the bonding force between the terminal and the exterior resin.</p>

<p> In the chip-type solid electrolytic capacitor of the present invention, a capacitor element in which a dielectric, an electrolyte, and a cathode layer are sequentially formed on the surface of a porous sintered body made of a valve acting metal from which an anode lead wire is derived, and an exterior resin at one end. An anode consisting of a substrate mounting surface portion exposed on the mounting surface side of the capacitor, and an anode portion whose other end is arranged substantially perpendicular to the substrate mounting surface portion and whose tip is connected to an anode lead wire derived from a capacitor element. The terminals, the substrate mounting surface portion whose one end is exposed to the mounting surface side of the exterior resin, and the other end are arranged substantially perpendicular to the substrate mounting surface portion and are connected to the capacitor element via a conductive adhesive. Insulation that covers the cathode terminal formed of the upright portion and the capacitor element, and also covers the anode terminal and the cathode terminal so as to have an exposed surface on the outer side surface substantially perpendicular to the substrate mounting surface portion and the substrate mounting surface portion. In a chip-type solid electrolytic capacitor including an exterior material made of the above resin, a through hole is provided in at least one of the rising portions of the anode terminal and the cathode terminal.</p><p> A capacitor element which is a terminal of the chip type solid electrolytic capacitor and is arranged substantially perpendicular to the substrate mounting surface portion whose one end is exposed on the mounting surface side of the exterior resin and one end via an anode lead wire. At least a cathode terminal consisting of an anode terminal composed of an upright portion connected to a capacitor element, a substrate mounting surface portion, and an upright portion formed substantially perpendicular to the substrate mounting surface and connected to a capacitor element via a conductive adhesive. One is configured to have a through hole in the upright portion.</p><p> In the method for manufacturing terminals of the chip type solid electrolytic capacitor, a substrate mounting surface portion in which one end is exposed on the mounting surface side of the exterior resin and an anode lead-out wire which is arranged substantially perpendicular to the substrate mounting surface portion and one end is provided. A cathode consisting of an anode terminal consisting of an upright portion connected to the capacitor element via a substrate, a substrate mounting surface portion, and an upright portion formed substantially perpendicular to the substrate mounting surface and connected to the capacitor element via a conductive adhesive. At least one of the terminals is connected to the substrate mounting surface portion substantially perpendicularly after providing a through hole in the upright portion.</p><p> A part of the substrate mounting surface portion is raised to form an upright portion, and then through holes are arranged at predetermined positions of the upright portion.</p><p> A substrate mounting surface portion in which the anode terminal and the rectangular plate forming the cathode terminal are extended inward from the product outer shape side surface direction along the substrate mounting surface which is the outer outer lower surface of the product, and the product outer side surface. The first bent portion is bent in the direction opposite to the mounting surface side so as to be parallel to each other, and then the second bent portion is folded back so that the leader wire joint portion becomes the apex to form an upright portion.</p>

<p> According to the present invention, by providing the through hole in the terminal portion, the through hole of the terminal is filled with the exterior resin when the exterior resin is coated, and an anchor effect is generated between the exterior resin and the cathode terminal or the anode terminal. It is possible to stably produce chip-type solid electrolytic capacitors with a high degree of coupling between terminals and exterior resin, and it is also effective against thermal and mechanical stress during or after board mounting, with productivity and reliability. It is possible to provide an improved chip-type solid electrolytic capacitor, terminals used therein, and a method for manufacturing the same.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of the chip-type solid electrolytic capacitor of the present invention along the center line. FIG. 2 is a cross-sectional view of the rising portion of the anode terminal of the chip-type solid electrolytic capacitor of the present invention. FIG. 3 is a cross-sectional view of the chip-type solid electrolytic capacitor of the present invention when mounted on a substrate.

First, regarding the fabrication of the capacitor element 1, the case where tantalum is used as the valve acting metal will be described. Tantalum powder is formed around the anode lead wire 2 and sintered at high vacuum and high temperature. Next, on the surface of the tantalum metal powder, Ta₂O₅Form an oxide film of. Furthermore, after immersing in manganese nitrate, it is thermally decomposed and MnO₂And subsequently, a cathode layer made of graphite and Ag is formed to obtain a capacitor element 1. The cathode layer MnO₂Instead, using a conductive polymer such as polythiophene or polypyrrole is effective in reducing ESR (equivalent series resistance). Further, as the valve acting metal, niobium, aluminum, titanium and the like can be used in addition to tantalum.

As shown in FIGS. 1 and 2, the board mounting surface portion 6d in which one end of the anode lead wire 2 derived from the capacitor element 1 is exposed to the mounting surface side of the exterior resin 4 and the other end are the substrate mounting surface portion 6d. It is electrically connected to the anode terminal 6 composed of the upright portion 6c having the through hole 6a, which is arranged substantially perpendicular to the above, at the lead wire joint portion 6b by a known means such as resistance welding and laser welding. Further, a cathode composed of a substrate mounting surface portion 5d having one end exposed to the mounting surface side of the exterior resin 4 and an upright portion 5c having a through hole 5a arranged substantially perpendicular to the substrate mounting surface portion 5d at the other end. The terminal 5 is connected to the capacitor element 1 via the conductive adhesive 3. Next, the exterior resin 4 is transfer-molded so as to cover the capacitor element 1, and then cut into a desired shape with a dicing saw to obtain a chip-type solid electrolytic capacitor.

In this chip-type solid electrolytic capacitor, since the exterior resin 4 is filled inside the through holes 5a and 6a of the cathode and anode terminal upright portions 5c and 6c during molding with the exterior resin 4, the cathode and anode terminals 5 and 6 and the exterior resin are filled. As shown in FIG. 8, when the substrate is mounted as shown in FIG. 3, the anchor effect works between the anode and the resin, that is, the inner (element side) and outer resins are bonded and not separated through the through hole of the terminal. Prevents troubles such as deterioration of electrical characteristics and reliability caused by cracks 12 due to mechanical and thermal stress received during or after mounting on the substrate 11 that occur in chip-type solid electrolytic capacitors with a conventional terminal structure. It becomes possible.

Next, a method of manufacturing terminals used in the chip-type solid electrolytic capacitor of the present embodiment will be described with reference to FIGS. 4, 5 and 6.

FIG. 4 is a perspective view showing the first embodiment of the cathode or anode terminal (lead frame for forming) of the present invention, and FIG. 4 (a) is a perspective view after forming a through hole in the upright portion. , FIG. 4 (b) is a perspective view after the board mounting surface portion is connected to the upright portion.

As shown in FIG. 4A, through holes 5a are formed in the cathode and anode terminal upright portions 5c and 6c made of a rectangular plate by known means such as punching, drilling, and laser machining to have a predetermined shape and a predetermined position. , 6a are provided, and as shown in Fig. 4 (b), the cathode and anode terminal board mounting surfaces 5d and 6d, which are also rectangular plates, are connected to the cathode terminals by means such as welding or bonding substantially vertically. 5 and the anode terminal 6 are formed.

FIG. 5 is a perspective view showing a second embodiment of the cathode or anode terminal of the present invention, and FIG. 5 (a) is a perspective view after forming the substrate mounting surface portion and the upright portion, and FIG. 5 (b). ) Is a perspective view after forming a through hole in the upright portion.

As shown in FIG. 5 (a), a part of the cathode and anode terminal board mounting surfaces 5d and 6d is raised by means such as coining to form standing portions 5c and 6c, and then as shown in FIG. 5 (b). Through holes 5a and 6a are provided in the upright portions 5c and 6c by known means such as punching, drilling, and laser machining to form the cathode terminal 5 and the anode terminal 6.

FIG. 6 is a perspective view showing a third embodiment of the cathode or anode terminal of the present invention, and FIG. 6A is a perspective view after forming a through hole in a rectangular plate. 6 (b) is a perspective view during the second bending process, FIG. 6 (c) is a perspective view after the third bending process, and FIG. 6 (d) is a perspective view after the finishing process. is there.

As shown in FIG. 6A, through holes 5a of the cathode and anode terminal substrates are formed in the terminal portion, which is a rectangular plate, in a predetermined shape and at a predetermined position by a known means such as punching, drilling, and laser machining. After 6a is provided, as shown in FIG. 6 (b), the substrate mounting surface portions 5d and 6d extending inward from the product outer shape side surface direction along the board mounting surface which is the outer outer lower surface of the product are first. At the bent portion 7, a 90 ° bending process is performed in the direction opposite to the mounting surface direction. Next, in the second bending portion 8, after bending 180 ° in the mounting surface direction, the third bending is performed as shown in FIG. 6 (c) so as to extend inward from the product outer shape side surface direction. The cathode terminal 5 and the anode terminal 6 are formed by bending the portion 9 at 90 °, and if necessary, crushing and tapping are performed as shown in FIG. 6 (d).

The cathode or anode terminal obtained by the manufacturing method according to the embodiment shown in FIGS. 5 and 6 has the substrate mounting surface portions 5d and 6d and the standing portions 5c and 6c integrally molded, so that the cathode or anode terminal has excellent electrical connectivity. Has excellent advantages.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and the design is changed such that the through hole is provided with an angle or a step is provided, or the number of through holes is provided. , Position, shape, etc. are included in the present invention even if there are design changes within a range that does not deviate from the gist of the present invention. That is, it goes without saying that various modifications and modifications that can be made by those skilled in the art are included.

The dimensions of the substrate mounting surface of the cathode terminal and the anode terminal are 0.5 mm in length x 0.65 mm in width x 0.1 mm in thickness, the dimensions of the upright part are 0.5 mm in height x 0.65 mm in width x 0.1 mm in thickness, and the size of the through hole. JIS C60068-2-21 is a chip-type solid electrolytic capacitor manufactured with a diameter of 0.15 mm and 10 chip-type solid electrolytic capacitors having the same configuration as the present invention, except that a through hole is not provided as a comparative example. Figure 7 shows the results of the adhesion test based on the "terminal strength test method".

In the chip-type solid electrolytic capacitor of the present invention, a through hole is provided in the upright portion of the terminal and the inside thereof is filled with the exterior resin, so that an anchor effect is generated between the terminal and the exterior resin and the fixing strength is high. It is shown that there is an increase compared to.

<figref num="1">The vertical sectional view along the center line of the chip type solid electrolytic capacitor of this invention.</figref><figref num="2">The cross-sectional view of the anode terminal upright part of the chip type solid electrolytic capacitor of this invention.</figref><figref num="3">Sectional drawing of the chip type solid electrolytic capacitor of this invention at the time of substrate mounting.</figref><figref num="4">A perspective view showing the first embodiment of the cathode or anode terminal of the present invention, FIG. 4 (a) is a perspective view after forming a through hole in the upright portion, and FIG. 4 (b) shows the substrate mounting surface portion connected to the upright portion. Perspective view after.</figref><figref num="5">A perspective view showing a second embodiment of the cathode or anode terminal of the present invention, FIG. 5 (a) is a perspective view after forming the substrate mounting surface portion and the upright portion, and FIG. 5 (b) is the formation of a through hole in the upright portion. Rear perspective view.</figref><figref num="6">A perspective view showing a third embodiment of the cathode or anode terminal of the present invention, FIG. 6 (a) is a perspective view after forming a through hole in a rectangular plate, and FIG. 6 (b) is a second bending. The perspective view during processing, FIG. 6 (c) is a perspective view after the third bending process, and FIG. 6 (d) is a perspective view after finish processing.</figref><figref num="7">The graph which shows the stickiness test result of this invention and the conventional chip type solid electrolytic capacitor.</figref><figref num="8">Cross-sectional view of a conventional chip-type solid electrolytic capacitor when mounted on a substrate.</figref>

Code description

1 Condenser element 2 Anode lead wire 3 Conductive adhesive 4 Exterior resin 5 Cathode terminal 5a (cathode terminal) Through hole 5c (cathode terminal) Standing part 5d (cathode terminal) Board mounting surface 6 Anode terminal 6a (anode terminal) through hole 6b (Anode terminal) Lead wire joint 6c (Anode terminal) Standing part 6d (Anode terminal) Board mounting surface part 7 First bending part 8 Second bending part 9 Third bending part 10 Solder 11 Board 12 Crack