JP2011077079A - Chip-type solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chip-type solid electrolytic capacitor which reduces internal connection failure of an anode portion. <P>SOLUTION: The chip-type solid electrolytic capacitor has: an anode lead line 2 led out therefrom; an anode connection terminal 4 and a cathode connection terminal which are provided opposite to a capacitor element 1, equipped with a cathode layer on the top surface of an insulation plate and connected to a capacitor element 1; an anode packaging terminal 5 and a cathode packaging terminal on the under surface of the insulation plate which are connected via through-holes to the anode connection terminal 4 and the cathode connection terminal respectively, and is provided with a support member 3, which is connected to the anode lead line 2 and the anode connection terminal 4, wherein the support member 3 has a height which varies by being pressed vertically with respect to the connection surface of the anode connection terminal 4 and is connected to the anode connection terminal 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a chip-type solid electrolytic capacitor.

  Conventionally, solid electrolytic capacitors using tantalum, niobium or the like as a valve action metal are small, have a large capacitance, are excellent in frequency characteristics, and are widely used in power supply circuits for CPUs. In addition, with the development of portable electronic devices, chip-type solid electrolytic capacitors are particularly becoming smaller and thinner. Among them, a product of a bottom electrode structure type has appeared that makes the internal structure of the capacitor more efficient and limits the volume of the capacitor element by limiting the electrode terminal to the mounting surface of the product. As a chip-type solid electrolytic capacitor having such a bottom electrode structure, for example, there is a technique disclosed in Patent Document 1.

  Conventional techniques will be described with reference to the drawings. FIG. 4 is a schematic cross-sectional view of the chip-type solid electrolytic capacitor as seen from the front. FIG. 5 is a perspective view of a conventional chip-type solid electrolytic capacitor viewed from the side.

  A chip-type solid electrolytic capacitor as shown in FIG. 4 conventionally uses a conversion substrate provided with electrode terminals for converting each electrode of the capacitor element 1 into a mounting terminal. This conversion board has a capacitor connection terminal surface on the upper surface of the insulating substrate, a mounting terminal surface on the lower surface, and a structure in which the upper and lower surfaces are electrically connected. A conventional chip-type solid electrolytic capacitor 15 is formed by sequentially forming a dielectric, an electrolyte, and a cathode layer on the surface of an anode body made of a porous sintered body made of a valve metal from which the anode lead wire 2 is led out. Form.

  Thereafter, the support member 3 made of a metal piece connected to the anode lead wire 2 of the capacitor element 1 by resistance welding, and the anode connection terminal 4 is connected to the support member 3 via high temperature solder or conductive adhesive 10. The capacitor element cathode connection surface 1 a is connected to the cathode connection terminal 6 through the conductive adhesive 11. The anode connection terminal 4 and the cathode connection terminal 6 are conversion substrates 12 having a glass epoxy layer 13 as a base material, and are connected to the anode mounting terminal 5 and the cathode mounting terminal 7 on the external mounting surface through the through holes 8, respectively. The external mounting surfaces 5a and 7a are covered with an exterior resin 9 so as to be exposed.

  After covering with the above-mentioned exterior resin 9, in order to adjust to the product outer shape, it is cut by dicing and a chip-type solid electrolytic capacitor is obtained.

JP 2008-270317 A

  So far, the structure of the conventional chip-type solid electrolytic capacitor has been described. However, in the case of mass production on an automated production line, the following problems have been concerned. This will be described with reference to the drawings. FIG. 6 is a perspective view as seen from the side of a conventional chip-type solid electrolytic capacitor. This is because the support member welding position 3a is shifted upward due to dimensional variation or welding state due to the combination of member supply lots. This indicates that the gap 14 has occurred. FIG. 7 is also a perspective view seen from the side of a conventional chip-type solid electrolytic capacitor. Since the amount of high-temperature solder or conductive adhesive 10 applied is small, the high-temperature solder or conductive adhesive connecting surface 10a is shifted downward. This indicates that the gap 14 has occurred.

  FIG. 8 shows a conventional arrangement of the capacitor element 1, the anode lead wire 2, and the support member 3, and the bottom of the capacitor element 1 and the bottom of the support member 3 are in the same position.

  As described above, in the conventional technique, variation in resistance welding accuracy position between the anode lead wire 2 and the support member 3 and variation in coating thickness accuracy of the high temperature solder or the conductive adhesive 10 may occur. Even if the bottom of the capacitor element 1 and the bottom of the support member 3 are at the same position, a gap 14 is generated between the support member 3 and the high-temperature solder or conductive adhesive 10, resulting in an electrical failure in the connection portion, and connection resistance. There is a concern about the state of the infinite, that is, the occurrence of open defects.

  The problem of the present invention is that the support member and the anode connection terminal do not become defective in opening even if there is a variation in resistance welding accuracy position between the anode lead wire and the support member, a variation in coating thickness accuracy of high-temperature solder or conductive adhesive, etc. The object is to provide a chip-type solid electrolytic capacitor.

  According to the chip-type solid electrolytic capacitor of the present invention, an anode lead wire is derived, and an anode connection terminal electrically connected to a capacitor element having a cathode layer and an upper surface via the anode lead wire and a support member, and A cathode connection terminal electrically connected to the cathode layer via a conductive adhesive; and an anode mounting terminal and a cathode mounting terminal electrically connected to the anode connection terminal and the cathode connection terminal, respectively, on the lower surface A chip-type solid electrolytic capacitor provided with a conversion substrate, wherein the support member has a bifurcated shape and is connected by pressing a bifurcated tip against the anode connection terminal.

  The support member of the chip-type solid electrolytic capacitor of the present invention is characterized in that the support member is made of a Fe—Ni alloy or a copper material.

  The support member of the chip-type solid electrolytic capacitor of the present invention is characterized in that it is connected to the anode connection terminal with a high-temperature solder or a conductive adhesive.

According to the present invention, the shape of the support member connected to the anode lead wire derived from the capacitor element is bifurcated, and the tip of the fork is pressed and connected to the anode connection terminal, whereby resistance welding between the anode lead wire and the support member is performed. Even if there is a variation in accuracy position, a variation in coating thickness accuracy of high-temperature solder or conductive adhesive, the accuracy variation can be absorbed, and the fixing reliability between the support member and the anode connection terminal is improved. .

The perspective view seen from the side of the chip type solid electrolytic capacitor of the present invention. The perspective view seen from the side surface which shows arrangement | positioning of the capacitor | condenser element, anode lead wire, and supporting member of the chip-type solid electrolytic capacitor of this invention. The figure which shows that the height of the supporting member of the chip type solid electrolytic capacitor of this invention changes. The schematic sectional drawing seen from the front which shows a chip type solid electrolytic capacitor. The perspective view seen from the side which shows the conventional chip type solid electrolytic capacitor. The perspective view seen from the side surface which shows that the clearance gap generate | occur | produced when the supporting member welding position of the conventional chip-type solid electrolytic capacitor shifted | deviated upwards. The perspective view seen from the side surface which shows that the clearance gap generate | occur | produced because the high temperature solder or conductive adhesive connection surface of the conventional chip-type solid electrolytic capacitor shifted | deviated downward. The perspective view seen from the side surface which shows arrangement | positioning of the capacitor | condenser element, anode lead wire, and supporting member of the conventional chip type solid electrolytic capacitor.

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

  First, an embodiment of the present invention will be described with reference to FIG. Capacitor element 1 has the same structure as that of the prior art, and is a cathode in which a dielectric, an electrolyte, and a cathode layer are sequentially formed on the surface of an anode body made of a porous sintered body made of a valve metal from which anode lead 2 is derived. It is the structure which has a part. Tantalum, niobium, aluminum or the like can be used as the valve metal.

  A support member 3 made of a metal piece having a bifurcated shape is welded to the anode lead wire 2 of the capacitor element 1 by resistance welding. The support member 3 is obtained by processing a plate material mainly composed of Fe-42% Ni42 alloy piece or copper as a material of the metal piece, and a support member welding position 3a having a flat portion for welding the anode lead wire 2; It consists of a variable portion connected to the anode connection terminal 4 via high temperature solder or conductive adhesive 10.

  As shown in FIG. 2, the variable portion of the support member 3 is in a state in which the bifurcated tip connected to the anode connection terminal protrudes downward from the bottom of the capacitor element 1 when it is welded to the anode lead wire 2.

  Then, when the support member 3 is connected and fixed to the anode connection terminal, a pressing force is applied in the vertical direction to the plane of the support member welding position 3a welded to the anode lead wire 2, and the variable part in contact is a letter C. And is plastically deformed until the gap described in FIGS. 6 and 7 does not occur. The surface of the anode connection terminal is preliminarily coated with high-temperature solder or a conductive adhesive, and the support member 3 and the anode connection terminal are fixedly connected in an optimal positional relationship. FIG. 3 shows a state in which the movable part of the support member 3 is opened in a letter C when a pressing pressure is applied.

  Even if a variation in resistance welding accuracy position between the anode lead wire 2 and the support member 3 and a variation in coating thickness accuracy of high-temperature solder or conductive adhesive, which have been a concern due to this action, can be absorbed. It is possible to improve the adhesion reliability between the support member 3 and the anode connection terminal.

  When high temperature solder is used for the connection means between the support member 3 and the anode connection terminal 4, the laser light is irradiated so as to avoid the welded anode lead wire 2 on the upper surface of the support member 3. The heat of the laser light is transmitted to the high temperature solder 10 through the support member 3, and the high temperature solder 10 can be efficiently melted by the heat. Further, when a conductive adhesive containing Ag or the like is used in the connection means between the support member 3 and the anode connection terminal 4, the connection is fixed by drying and curing.

  Returning to FIG. 1, the cathode portion of the capacitor element 1 is connected to the cathode connection terminal via the conductive adhesive 11. The conversion substrate 12 has a glass epoxy layer 13 as a base material, and has an anode connection terminal 4 and a cathode connection terminal, an anode mounting terminal 5 and a cathode mounting terminal which are connected through the through holes 8 respectively. Further, the entire outer mounting surface 5a of the conversion substrate 12 and a part of the glass epoxy layer 13 are exposed with an exterior resin 9 such as glass-containing epoxy resin or liquid crystal polymer, transfer mold resin, or liquid epoxy resin. The chip-type solid electrolytic capacitor 15 is obtained by covering and cutting the conversion substrate 12 and the exterior resin 9 into predetermined dimensions.

(Example)
Examples will be described with reference to FIGS. 1 to 3.

  Hereinafter, examples will be described with reference to FIG. 1 used in the embodiment. Since the manufacturing of the capacitor element 1 is a known technique, the details are omitted. A case where tantalum is used as the valve metal will be described. A tantalum powder was molded around a tantalum wire with a press and sintered at high vacuum and high temperature to produce a tantalum sintered pellet. Next, the sintered pellet was energized with 15 V in an aqueous phosphoric acid solution and anodized to form an oxide film on the surface of the sintered body. Further, after being immersed in manganese nitrate, it was thermally decomposed to form manganese dioxide which is a solid electrolyte, and subsequently a cathode layer made of graphite and silver paste was formed to obtain capacitor element 1. If a conductive polymer such as polythiophene or polypyrrole is used instead of manganese dioxide, which is a solid electrolyte, it is easy to obtain a low ESR as one capacitor element.

  Next, the conversion substrate 12 used in Example 1 was based on glass epoxy. An anode connection terminal 4 and a cathode connection terminal (cathode connection terminal 6 shown in FIG. 4) are formed on the conversion substrate 12, and an external mounting surface (external connection shown in FIG. 4) is formed on the opposite capacitor mounting surface. An anode mounting terminal 5 and a cathode mounting terminal (cathode mounting terminal 7 shown in FIG. 4) each having a mounting surface 7a) are formed. Further, in order to make the anode connection terminal 4 and the cathode connection terminal 6, the anode mounting terminal 5, and the cathode mounting terminal 7 conductive, through holes 8 were formed in the conversion substrate 12.

  Next, the state of the support member 3 when it is welded to the anode lead wire 2 will be described with reference to FIG. As shown in FIG. 2, the support member 3 connected to the anode lead wire 2 by resistance welding had a thickness of 0.03 mm, and was obtained by punching from a metal plate containing copper as a main component and bending it. The dimension of the bifurcated variable portion formed perpendicular to the plane of the support member welding position 3 a was set to a length protruding downward from the bottom of the capacitor element 1. At this time, the tip of the variable portion of the support member 3 needs to be opened outward, so that it is expanded from the root portion.

  Returning to FIG. 1, the support member 3 connected to the capacitor element 1 via the anode lead wire 2 is disposed at a predetermined position of the anode connection terminal 4, and the plane of the support member welding position 3 a welded to the anode lead wire 2. A pressure was applied to the part in the vertical direction. Then, the variable portion of the support member 3 in contact with the anode connection terminal 4 was deformed into a square shape at an angle of 85 degrees to 95 degrees, which is judged to be the optimum state to be connected.

  The surface of the anode connection terminal 4 is coated with high-temperature solder 10 in advance, and the high-temperature solder used was composed mainly of Sn, Ag, and Cu. The high-temperature solder 10 is a Sn—Ag—Cu composite material which is melted by heat of 200 ° C. or higher and once cured, it does not remelt even at 300 ° C. Laser light was used to melt the high-temperature solder. The laser beam is irradiated with a semiconductor laser having a wavelength of 940 nm, the laser beam diameter is set to 0.35 mm, and the laser beam is set to 2 at both ends so as to avoid the welded anode lead wire 2 on the upper surface of the support member welding position 3a. The part was irradiated simultaneously. As a result, the tip of the variable portion of the support member 3 could be connected and fixed in a state where no gap was generated on the surface of the anode connection terminal 4 while maintaining an angle of 85 to 95 degrees.

  Even if variations in the resistance welding accuracy position between the anode lead wire and the support member, and variations in the coating thickness accuracy of the high-temperature solder or conductive adhesive, which were concerned by the above embodiments, can be absorbed. Thus, it is possible to improve the adhesion reliability between the support member 3 and the anode connection terminal 4.

  The cathode connection surface of the capacitor element 1 (capacitor element cathode connection surface 1a shown in FIG. 4) was connected to the cathode connection terminal of the conversion substrate 12 by applying a conductive adhesive 11 containing Ag. Next, after heat-molding by using a glass-containing epoxy resin as the exterior resin 9, the exterior surface of the chip-type solid electrolytic capacitor 15 is cut by a dicing saw in order to adjust the product external dimensions, A chip-type solid electrolytic capacitor 15 of this example was obtained.

(Comparative example)
After the support member 3 having a rectangular parallelepiped shape according to the prior art was resistance-welded to the anode lead wire of the capacitor element, other manufacturing methods were carried out in the same manner as in the present invention to produce a solid electrolytic capacitor. Thus, a conventional solid electrolytic capacitor as a comparative example was produced.

  The open defect rate of the solid electrolytic capacitor of the Example of this invention and the solid electrolytic capacitor which is a prior art was compared. The open failure was detected by measuring the connection resistance by electrical inspection.

  Table 1 shows the results of the present invention and the prior art.

  From Table 1, it is confirmed that the open defects are reduced in the examples as compared with the comparative examples, and the effect of the present invention can be seen.

  The shape of the support member 3 is not limited to the above shape, and has a variability capable of absorbing the gap 14 generated between the support member 3 and the high-temperature solder or the conductive adhesive 10, and is a pressing pressure in the manufacturing process. Any shape and size may be used as long as the anode lead wire 2 and the anode connection terminal 4 can be connected via the high-temperature solder or the conductive adhesive 10.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to these embodiments, and the present invention is not limited to the scope of the present invention. Included in the invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Capacitor element 1a Capacitor element cathode connection surface 2 Anode lead wire 3 Support member 3a Support member welding position 3b Support member movable area 4 Anode connection terminal 5 Anode mounting terminal 5a, 7a External mounting surface 6 Cathode connection terminal 7 Cathode mounting terminal 8 Through Hole 9 Exterior resin 10 High-temperature solder or conductive adhesive 10a High-temperature solder or conductive adhesive connecting surface 11 Conductive adhesive 12 Conversion substrate 13 Glass epoxy layer 14 Gap 15 Chip-type solid electrolytic capacitor

Claims (3)

  An anode lead wire is led out, a capacitor element having a cathode layer, an anode connecting terminal electrically connected to the upper surface via the anode lead wire and a support member, and an electric connection via the cathode layer and a conductive adhesive A chip-type solid electrolytic capacitor having a cathode connection terminal to be electrically connected and a conversion substrate having an anode mounting terminal and a cathode mounting terminal electrically connected to the anode connection terminal and the cathode connection terminal, respectively, on a lower surface thereof The support member has a bifurcated shape, and the tip of the bifurcated end is pressed against the anode connection terminal for connection.   The chip-type solid electrolytic capacitor according to claim 1, wherein the support member is made of an Fe—Ni alloy or copper and an alloy thereof.   3. The chip-type solid electrolytic capacitor according to claim 1, wherein the support member is connected to the anode connection terminal by solder having a heat-resistant temperature of 300 ° C. or less after processing or a conductive adhesive. 4.

Images