JP2006332403A - Lead frame, manufacturing method of solid electrolytic capacitor of lower-side electrode type employing the same, and solid electrolytic capacitor of lower-side electrode type manufactured by the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor of lower-side electrode type manufactured by using a lead frame of a structure, wherein the current path distance between the anode and the cathode is short, the skin effect at a high-frequency band is high, and the ESL and ESR of the whole capacitor can be fully lowered. <P>SOLUTION: The capacitor employs the lead frame of the structure, wherein the connection range for connecting a cathode terminal and a capacitive element 11 by a conductive adhesive extends from a cathode side toward a part close to a reference face side. The reference face is a connection end face at an anode lead wire embedded face of the capacitive element 11 in a cathode terminal forming part 22 provided facing an anode terminal forming part 21, so that the cathode terminal extends up to the anode terminal side and is exposed on the mounting side. After the capacitive element 11 connected to the lead frame has been molded by an outer packaging resin 19, the molded capacitive element 11 is cut along an anode side cut face 23a and a cathode side cut face 23b, and a chip body separated from the lead frame is obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lead frame for forming a terminal used mainly for the production of a bottom electrode type solid electrolytic capacitor having an electrode directly drawn out to a substrate mounting side, a method for producing a bottom electrode type solid electrolytic capacitor using the same, and The present invention relates to a bottom electrode type solid electrolytic capacitor manufactured by:

  Conventionally, solid electrolytic capacitors using tantalum, niobium, or the like as a valve action metal are widely used in CPU decoupling circuits, power supply circuits, and the like due to their small size, large capacitance, and excellent frequency characteristics. In addition, with the development of portable electronic devices, the ESR (equivalent series resistance) and ESL (inductance component) of the entire capacitor, particularly in the high frequency band, are small, and the bottom electrode type solid electrolytic capacitor having an electrode drawn directly to the board mounting side Commercialization is progressing.

  As such a bottom electrode type solid electrolytic capacitor, a case is provided in which the lower ends of the anode piece and the cathode piece arranged opposite to each other are connected by a connecting piece, and the capacitor element is arranged so as to be electrically connected between the two pole pieces. Then, after covering between the two pole pieces with synthetic resin, the connecting piece is polished or deleted to electrically separate the anode piece and the cathode piece, and the opposite portion of the two pole pieces facing the circuit board is exposed. And the like (see Patent Document 1), and those having a structure in which at least two cathode exposed portions exposed from the exterior resin are provided on the same plane with respect to the cathode terminal (see Patent Document 2). .

JP 2003-133177 A (summary, FIG. 1) JP 2004-349270 A (summary, FIG. 1)

  In the case of the lower surface electrode type solid electrolytic capacitors according to Patent Document 1 and Patent Document 2 described above, according to the technology of the electrode terminal structure, the current path distance between the anode and the cathode and the conductive path distance from the capacitor element to the circuit board. The skin effect in the high frequency band is reduced, and the ESR (equivalent series resistance) and ESL (inductance component) of the entire capacitor are increased remarkably, resulting in a skin effect in the high frequency band. There is a problem that ESL and ESR of the entire capacitor cannot be made sufficiently low.

  The present invention has been made to solve such problems, and its technical problem is that the current path distance between the anode and the cathode is short, the skin effect in the high frequency band is large, and the ESL of the entire capacitor. It is another object of the present invention to provide a lead frame having a structure with a sufficiently low ESR, a method of manufacturing a bottom electrode type solid electrolytic capacitor using the lead frame, and a bottom electrode type solid electrolytic capacitor manufactured thereby.

  According to the present invention, in a lead frame for forming a terminal used for manufacturing a bottom electrode type solid electrolytic capacitor having an electrode that is directly drawn out to a substrate mounting side, an anode terminal forming portion and a cathode terminal for forming an anode terminal are provided. A cathode terminal forming portion for forming is provided opposite to the anode terminal forming portion, and a part of the anode terminal forming portion is deformed in a direction perpendicular to the mounting surface to form a concave portion on the mounting surface side, and on the opposite side to the mounting surface. An uneven part to be a convex part is formed, a plating process is applied to the concave part, and the convex part is connected to the flat part that is parallel to the mounting surface and serves as a welding base, and is connected to the flat part as the mounting part moves away from the flat part. And a connecting end surface of the capacitor element having a connection range for connecting the cathode terminal and the capacitor element with the conductive adhesive at the embedded portion of the anode lead wire. Lead frame from the cathode portion as a reference plane which is positioned to extend in the reference surface portion closer to obtain.

  Further, according to the present invention, in the lead frame, the cathode terminal is electrically conductively bonded so that a part or all of the cathode terminal is exposed on the mounting surface in accordance with a connection range extending from the cathode side portion toward the reference surface side portion. A lead frame to be connected by the agent is obtained.

  Furthermore, according to the present invention, in any one of the above lead frames, a lead frame can be obtained in which the concavo-convex portion is formed by drawing or coining.

  In addition, according to the present invention, in any one of the above lead frames, a lead frame having a polygonal shape or a shape in which at least one side is a straight line is obtained as a cross-sectional shape parallel to the mounting surface in the recess. .

  On the other hand, according to the present invention, in any one of the above lead frames, the surface substantially perpendicular to the mounting surface in the convex portion is directed in a direction parallel to the mounting surface and separated from the mounting surface. A lead frame provided with a protrusion or notch in position is obtained.

  On the other hand, according to the present invention, in any one of the above lead frames, the anode terminal forming portion and the cathode terminal forming portion include at least Ag, Au, Cu, Pd, and Sn to form an anode terminal and a cathode terminal, respectively. A lead frame in which a film including one is formed is obtained.

  Further, according to the present invention, in any one of the lead frames, the surface in the frame thickness direction in the anode terminal forming portion and the cathode terminal forming portion has Ag, A lead frame in which a film containing at least one of Au, Cu, Pd, and Sn is formed is obtained.

  Furthermore, according to the present invention, there is provided a method of manufacturing a bottom electrode type solid electrolytic capacitor using any one of the above lead frames, a capacitor joining step for joining a capacitor element on the lead frame, and the capacitor element and the lead frame. A resin molding process in which the outer resin is molded, and the lead frame, the anode lead wire of the capacitor element, and the outer resin are cut while leaving one of the plating surfaces along one of the concave plating surfaces. The manufacturing method of the bottom surface electrode type solid electrolytic capacitor including the outer surface forming step for forming the outer surface which becomes the side surface of the lower surface electrode is obtained. In this method of manufacturing a bottom electrode type solid electrolytic capacitor, in the capacitor bonding step, a capacitor element is bonded to the anode terminal forming portion, and an insulating resin is applied to a part of the anode terminal forming portion prior to the bonding. It is preferable.

  In addition, according to the present invention, there is provided a bottom electrode type solid electrolytic capacitor manufactured by any one of the above methods for manufacturing a bottom electrode type solid electrolytic capacitor, wherein the capacitor element has a valve action metal from which an anode lead wire is derived. A dielectric layer, an electrolyte layer, and a cathode layer are sequentially formed on the surface of a porous sintered body made of an anode terminal formed on the anode terminal forming portion, and one end is connected to the anode lead wire. In addition, the other end is provided as an external connection terminal. The cathode terminal formed in the cathode terminal forming portion is connected at one end to the cathode layer in the capacitor element and at the other end as the external connection terminal. The exterior resin covers the capacitor element, and is packaged so as to have an exposed surface on the mounting surface of the anode terminal and the cathode terminal on the substrate and an outer surface substantially perpendicular to the mounting surface. Polar type solid electrolytic capacitor is obtained.

  In the case of the lead frame of the present invention, the connection end surface when the connection range (disposition of the cathode terminal forming portion) for connecting the cathode terminal and the capacitor element with the conductive adhesive is in the anode lead wire embedded surface portion of the capacitor element is A part of or all of the mounting surface is exposed depending on the connection range in which the cathode terminal extends from the cathode side portion to the reference surface side portion as the reference surface and the cathode terminal extends from the cathode side portion to the reference surface side portion. Thus, since the structure is connected by a conductive adhesive (that is, a structure in which the cathode terminal extends to the anode terminal side and is exposed on the mounting surface), the current path between the cathode and the anode is shortened, and the high frequency band As a result, the ESL and ESR of the entire capacitor can be reduced. In addition, in such a lead frame, in consideration of the fact that the plating becomes a current path due to the skin effect in the high frequency band, a plating having a low electrical resistance is selected, and a cathode terminal which is a part of the current path between the anode and the cathode When cutting in order to adjust the shape with respect to the thickness direction with the anode terminal, the structure is such that the ESL can be lowered by cutting so that the plating surface remains in the concave portion of the electrode terminal forming portion after the cutting process. The current path between them is shortened and the ESL is sufficiently reduced. Therefore, in the manufacturing method of the bottom electrode type solid electrolytic capacitor using such a lead frame, the skin effect in the high frequency band is increased, and the ESL and ESR of the entire capacitor can be lowered, and the bottom electrode type solid electrolytic capacitor having excellent reliability Capacitors can be provided with high productivity.

  First, prior to the description of the lead frame of the present invention, the method of manufacturing the bottom electrode type solid electrolytic capacitor using the lead frame, and the bottom electrode type solid electrolytic capacitor manufactured thereby, the premise technique of the present invention will be described. A bottom electrode type solid electrolytic capacitor will be described.

  The present applicant has made proposals based on Japanese Patent Application No. 2004-002180, Japanese Patent Application No. 2004-358094, Japanese Patent Application No. 2004-358095, etc. as bottom electrode type solid electrolytic capacitors related to the premise technology of the present invention. .

  FIG. 4 exemplifies the basic structure of the bottom electrode type solid electrolytic capacitor (structure proposed as Japanese Patent Application No. 2004-358095) according to the premise technique of the present invention, and FIG. FIG. 4B relates to a side view from the cathode side, FIG. 2B relates to a front view seen through the inside from the front side, and FIG.

  In this bottom electrode type solid electrolytic capacitor, by applying a lead frame, a dielectric layer, an electrolyte layer, and a cathode layer are sequentially formed on the surface of a porous sintered body made of a valve metal from which an anode lead wire 72 is led. With respect to the capacitor element 71 formed, a lower electrode type anode terminal 73 having one end connected to the anode lead wire 72 and the other end serving as an external connection terminal is provided in the anode terminal forming portion, and the capacitor element 71 A cathode electrode 74 having a bottom electrode type, one end of which is connected to the cathode layer and the other end serving as an external connection terminal, is provided in the cathode terminal forming portion, and further the anode is formed by an exterior resin 99 so as to cover the capacitor element 71. The terminals 73 and the cathode terminals 74 are packaged so as to have exposed surfaces on the mounting surfaces of the terminals 73 and the cathode terminals 74 and the outer surfaces substantially perpendicular to the mounting surfaces.

  However, the anode terminal 73 here is formed in an anode terminal forming part in which an insulating resin 77 is partially applied in advance, and the cathode terminal 74 can be connected to the capacitor element 71 using the conductive adhesive 80. The plated fillet surface 76a is exposed on the anode side and the plated fillet surface 76b is exposed on the cathode side. 4A shows a substantially U-shaped anode terminal cut surface 79, FIG. 4C shows a cathode terminal cut surface 78, and FIG. 4B shows one end surface and the other end surface in the longitudinal direction. FIG. 6 shows a state in which one surface of the concave portion plated on the inner surface becomes an anode-side fillet surface 76a and a cathode-side fillet surface 76b. The anode-side protrusion 25a exposed at one end surface in the longitudinal direction and the cathode-side protrusion 25b exposed at the other end surface are provided as terminals for obtaining an anchor effect into the exterior resin 99.

  FIG. 5 is a front view showing a state before cutting, in which the capacitor element 71 is joined to the lead frame provided in the bottom electrode type solid electrolytic capacitor and molded with the exterior resin 99, as seen through the inside from the front side. is there.

  Here, as a manufacturing process of such a bottom electrode type solid electrolytic capacitor, first, a flat lead frame having a predetermined shape is formed, and an anode terminal forming portion 81 for forming an anode terminal 73 in the lead frame is provided to provide an anode. Inclination processing of the anode terminal uneven portion for forming the uneven portion through drawing or crushing processing of the anode joint portion for securing the connectivity between the terminal 73 and the anode lead wire 72, and the cathode terminal for forming the cathode terminal 74 In order to provide the forming portion 82, after performing unevenness processing for electrode formation including processing of the unevenness portion of the cathode terminal that forms the unevenness portion through drawing or crushing processing of the cathode junction portion, plating processing of the lead frame and capacitor The capacitor element 71 is bonded and fixed to bond the element 71 to the lead frame, and further molded by the exterior resin 99. The cutting process along the anode side cut surface 83a and the cathode side cut surface 83b (located near the outside of the anode side fillet surface recess 84a and the cathode side fillet surface recess 84b) of the exterior resin 99 and the lead frame. It is necessary. However, if the plating layer remains after the lead frame forming process and the concave and convex process for electrode terminal formation, the lead frame plating process should be performed in advance before the lead frame forming process as a cost measure. You may make it do.

  In any case, in a state where the capacitor element 71 is bonded to the lead frame and molded with the exterior resin 99, the anode terminal forming portion 81 and the cathode terminal forming portion 82 are formed, and the anode side fillet surface recess 84a and the cathode side are formed. The fillet surface recess 84b performs a cutting process along the anode-side cutting surface 83a and the cathode-side cutting surface 83b to obtain a chip body, thereby forming a fillet surface after cutting. Here, the anode terminal forming portion 81 and the cathode terminal forming portion 82 are characterized in that a plating process is performed after cutting by providing a plated recess.

  However, referring to FIG. 4B, the connection range for connecting the cathode terminal 74 and the capacitor element 71 with the conductive adhesive 80 is the anode lead of the capacitor element 71 as in the structure according to this premise technique. The connection end surface in the line embedding surface portion is present only at the position closer to the cathode side with the reference position 17 as a part, and a part of the mounting surface is exposed according to the connection range in which the cathode terminal 74 exists in the portion closer to the cathode side. Thus, if the structure is connected by the conductive adhesive 80 (in other words, the cathode terminal 74 does not exist near the reference position 17 side and is not exposed on the mounting surface near the reference position 17 side), the anode and The distance of the current path between the cathodes is increased, and the ESL and ESR of the entire capacitor in the high frequency band are increased. That is, in the case of the bottom electrode type solid electrolytic capacitor according to the premise technique proposed by the present applicant, the current path from the capacitor element 71 to the circuit board becomes long due to the electrode terminal structure in any case. As in the case of No. 1 and Patent Document 2, there is a drawback that the skin effect in the high frequency band is small and the ESR and ESL of the entire capacitor are increased.

  Therefore, in the lead frame according to the best mode of the present invention, the anode terminal is formed in the basic structure for terminal formation used for the production of the bottom electrode type solid electrolytic capacitor having the electrode directly drawn to the substrate mounting side. An anode terminal forming portion for forming a cathode terminal and a cathode terminal forming portion for forming a cathode terminal are provided to face each other, and a portion of the anode terminal forming portion is deformed in a direction perpendicular to the mounting surface to form a recess on the mounting surface side. In addition, a concave and convex portion that is a convex portion is formed on the side opposite to the mounting surface, plating processing is performed on the concave portion, and the convex portion is connected to a flat portion that is parallel to the mounting surface and serves as a welding base and a flat portion. And an inclined portion that is inclined so as to approach the mounting surface as the distance from the substrate is increased, and a connection range (that is, arrangement of the cathode terminal forming portion) for connecting the cathode terminal and the capacitor element with the conductive adhesive is condensate. It has the extending Mashimashi have been positioned structure in the reference position side portion near the connecting end face from a cathode-side portion as a reference position of the anode be in the lead embedding surface of the element. However, this lead frame has a structure in which the cathode terminal is connected by a conductive adhesive so that part or all of the cathode terminal is exposed on the mounting surface in accordance with the connection range extending from the cathode side portion toward the reference position side portion. It is preferable to do. According to such a basic structure of the lead frame, the current path between the cathode and the anode is shortened, the skin effect in the high frequency band is increased, and the ESL and ESR of the entire capacitor are sufficiently lowered.

  In addition, the uneven portion can be formed by drawing or coining, and the inclined portion can also be formed by crushing. The cross-sectional shape parallel to the mounting surface in the recess is preferably a polygonal shape or a shape having at least one side as a straight line. Such a concave shape facilitates cutting for separating the chip from the lead frame.

  Furthermore, it is preferable that a protrusion or a notch that is directed in a direction parallel to the mounting surface and away from the mounting surface is provided on a surface that is substantially perpendicular to the mounting surface in the convex portion. Thus, when a projection part or a notch part is provided in a convex part, it will become an anchor to exterior resin and the adhering force will increase.

  In addition, a film containing at least one of Ag, Au, Cu, Pd, and Sn may be formed on the anode terminal forming portion and the cathode terminal forming portion to form the anode terminal and the cathode terminal, respectively. Preferably, a film containing at least one of Ag, Au, Cu, Pd, and Sn is formed on the surface in the frame thickness direction of the anode terminal forming portion and the cathode terminal forming portion to form the anode terminal and the cathode terminal, respectively. It is also preferable that it is formed. As described above, when a structure including at least one of Ag, Au, Cu, Pd, and Sn is formed on the anode terminal forming portion and the cathode terminal forming portion, the bonding strength with solder or the like at the interface is increased. In particular, the current path in the high frequency band is obtained by the relational expression that the depth δ of the skin effect is δ = (ρ / πfμ) 1/2, where ρ is the resistivity, f is the frequency, and μ is the magnetic permeability. Since the surface current path of several tens of μm or less is affected by the skin effect when the band is reached, it can be said that it is best to lower ESL if a structure plated with Au with a low specific resistance ρ is adopted. Further, the thickness direction of the cathode terminal and anode terminal which are part of the current path between the anode and the cathode is cut in order to adjust the shape of the electrode terminal forming portion (anode terminal forming portion, cathode terminal forming portion). If it cuts so that a plating surface may remain in a crevice, ESL can be lowered.

  By the way, in the manufacturing method of the bottom electrode type solid electrolytic capacitor of the present invention using any one of these lead frames, a capacitor joining step for joining the capacitor elements on the lead frame, and the capacitor elements and the lead frame are molded with an exterior resin. Resin mold process to be molded and outer surface that becomes the side surface of the product by cutting the lead frame, the anode lead wire of the capacitor element, and the exterior resin while leaving one of the plated surfaces along one of the plated surfaces of the recess And an outer surface forming step for forming the substrate. However, in the method of manufacturing the bottom electrode type solid electrolytic capacitor, in the capacitor joining step, the capacitor element is joined to the anode terminal forming portion, and an insulating resin is applied to a part of the anode terminal forming portion prior to joining. It is preferable to do so.

  Further, in the bottom electrode type solid electrolytic capacitor manufactured by such a method of manufacturing a bottom electrode type solid electrolytic capacitor, an anode lead wire is derived for the capacitor element as in the case of the structure of the premise technique described above. In this case, a dielectric layer, an electrolyte layer, and a cathode layer are sequentially formed on the surface of a porous sintered body made of a valve metal. One end is connected to the other end, and the other end is provided as an external connection terminal. For the cathode terminal formed in the cathode terminal forming portion, one end is connected to the cathode layer in the capacitor element. The other end is provided as an external connection terminal, and the exterior resin covers the capacitor element, and the mounting surface of the anode terminal and the cathode terminal on the substrate and the mounting surface thereof It may be assumed to be exterior to have an exposed surface perpendicular to the outer surface. Also in this bottom electrode type solid electrolytic capacitor, the lead frame structure is improved, so the current path between the anode and the cathode is short, the skin effect in the high frequency band is increased, and the ESL and ESR of the entire capacitor are reduced. It becomes excellent in reliability that can be valuated.

  Hereinafter, the lead frame of the present invention, a method for producing a bottom electrode type solid electrolytic capacitor using the lead frame, and a bottom electrode type solid electrolytic capacitor produced thereby will be specifically described with reference to examples.

  1A and 1B show the basic structure of a bottom electrode type solid electrolytic capacitor according to Example 1 of the present invention. FIG. 1A is a side view from the anode side, and FIG. FIG. 4C relates to a side view from the cathode side. FIG. In FIG. 1B, the hatched portion shows the removal surface of the exterior resin 19.

  Also in this bottom electrode type solid electrolytic capacitor, by applying a lead frame described later, a dielectric layer, an electrolyte layer, a cathode are formed on the surface of a porous sintered body made of a valve metal from which the anode lead wire 12 is derived. For the capacitor element 11 formed by sequentially forming layers, a bottom electrode type anode terminal 13 having one end connected to the anode lead wire 12 and the other end serving as an external connection terminal is provided in the anode terminal forming portion, and A bottom electrode type cathode terminal 14 having one end connected to the cathode layer in the capacitor element 11 and the other end serving as an external connection terminal is provided in the cathode terminal forming portion, and further, an exterior resin so as to cover the capacitor element 11 In the case of the prior art, the mounting surface of the anode terminal 13 and the cathode terminal 14 with respect to the substrate and the outer surface substantially perpendicular to the mounting surface are exposed by 19. Although the structure is the same, here, the connection end face for connecting the cathode terminal 13 and the capacitor element 11 with the conductive adhesive 20 is the anode lead wire embedded surface portion of the capacitor element 11, and the reference end face 17 is the connection end face. As shown in FIG. 4, the structure extends from the cathode side portion toward the reference surface 17 side portion. That is, in this bottom electrode type solid electrolytic capacitor, by using the improved lead frame, all (or even on the mounting surface) according to the connection range in which the cathode terminal 14 extends from the cathode side portion toward the reference surface 17 side portion. It may be connected by the conductive adhesive 20 so that it may be partly exposed.

  In addition, the anode terminal 13 here is formed in the anode terminal forming portion (note that the anode terminal forming portion here is also preferably partially coated with an insulating resin in advance). Is formed on the cathode terminal forming portion so that it can be connected to the capacitor element 11 using the conductive adhesive 20, and the anode side is plated with a fillet surface 15a, and the cathode side is plated with a fillet surface. 15b is exposed. 1A shows a substantially U-shaped anode terminal cut surface 16, FIG. 1C shows a cathode terminal cut surface 18, and FIG. 1B shows one end surface and the other end surface in the longitudinal direction. FIG. 6 shows a state in which one surface of the recess whose inner surface is plated becomes an anode-side fillet surface 15a and a cathode-side fillet surface 15b. In this case, the anode side protrusion 25a exposed at one end surface in the longitudinal direction and the cathode side protrusion 25b exposed at the other end surface are provided as terminals for obtaining an anchor effect into the exterior resin 19.

  FIG. 2 is a front view showing the state before cutting, in which the capacitor element 11 is bonded to the lead frame provided in the bottom electrode type solid electrolytic capacitor and molded with the exterior resin 19, as seen through the inside from the front side. is there.

  This lead frame has a basic structure for forming a terminal used for manufacturing a bottom electrode type solid electrolytic capacitor having an electrode directly drawn to a substrate mounting side (not shown), and an anode terminal for forming an anode terminal 13 The forming portion 21 and the cathode terminal forming portion 22 for forming the cathode terminal 14 are provided to face each other, and the cathode terminal 14 formed in the cathode terminal forming portion 22 is formed in the anode terminal forming portion 21. The structure extends to the terminal 13 side and is exposed on the mounting surface. Among these, the anode terminal forming portion 21 is partially deformed in a direction perpendicular to the mounting surface to form a concave portion on the mounting surface side and a convex portion on the side opposite to the mounting surface, and a drawing process or coining process ( For example, crushing). Here, the concave portion is plated, and the convex portion is parallel to the mounting surface and is connected to the flat portion and the inclined portion 26 which is inclined so as to approach the mounting surface as the flat portion is connected to the flat portion. Is formed. The inclined portion 26 can be formed by crushing. If the cross-sectional shape parallel to the mounting surface in the recess is a polygonal shape or a shape having at least one side as a straight line, cutting for separating the chip from the lead frame is facilitated. In addition, if a protrusion or a notch is provided on a surface that is substantially perpendicular to the mounting surface in the convex portion and is directed in a direction parallel to the mounting surface and away from the mounting surface, It becomes an anchor to the exterior resin 19 to increase the fixing force.

  By the way, a film containing at least one of Ag, Au, Cu, Pd, and Sn is formed on the anode terminal forming portion 21 and the cathode terminal forming portion 22 to form the anode terminal 13 and the cathode terminal 14, respectively. In addition, in order to form the anode terminal 13 and the cathode terminal 14 on the surface in the frame thickness direction in the anode terminal forming part 21 and the cathode terminal forming part 22, respectively, Ag, Au, Cu, Pd, Sn If a film including at least one film is formed, the bonding force with solder or the like at the interface increases.

  FIG. 3 is a flowchart showing a manufacturing process of the bottom electrode type solid electrolytic capacitor.

  Here, as a manufacturing process of the bottom electrode type solid electrolytic capacitor, a flat lead frame having a predetermined shape is first formed (step S1) by the same procedure as described in the premise technique, An anode terminal for providing an anode terminal forming portion 21 for forming the anode terminal 13 and forming an uneven portion through drawing processing or crushing processing of an anode joint portion for securing the connectivity between the anode terminal 13 and the anode lead wire 12 Inclination processing of the concavo-convex portion (step S2), and processing of the cathode terminal concavo-convex portion that forms the concavo-convex portion through drawing processing or crushing processing of the cathode joint portion in order to provide the cathode terminal forming portion 22 for forming the cathode terminal 14 After the concavo-convex process for forming the electrode including the lead frame, the lead frame plating process (step S3) and the capacitor element 11 are joined to the lead frame. The fixing and fixing of the capacitor element 11 to be fixed (step S4) is performed, and further molding with the exterior resin 19 (step S5) is performed, and then the anode side cut surface 23a and the cathode side cut surface of the exterior resin 19 and the lead frame Cutting (step S6) is required along the line 23b (located near the outside of the anode side fillet surface recess 24a and the cathode side fillet surface recess 24b). However, in the inclination processing of the anode terminal uneven portion (step S2), only when drawing is performed, the formation of the recess is plated on the planar lead frame and then the lead frame forming processing (step S1) and It is also possible to adopt a procedure for processing and forming the concave portion by performing the concave and convex processing for electrode formation including the inclination processing (step S2) of the concave and convex portion of the anode terminal.

  The process of fixing and fixing the capacitor element 11 here (step S4) corresponds to the capacitor bonding step of bonding the capacitor element 11 on the lead frame in the above-described method of manufacturing the bottom electrode type solid electrolytic capacitor, and the exterior resin 19 (Step S5) corresponds to a resin molding process in which the capacitor element 11 and the lead frame are molded with the exterior resin 19, and the cutting (step S6) processing is performed on one of the plated surfaces along one of the plated surfaces of the recesses. This corresponds to an outer surface forming step in which the lead frame, the anode lead wire 12 of the capacitor element 11 and the exterior resin 19 are cut to form an outer surface which is a side surface of the product while leaving one of them. In addition, as described above, in the capacitor bonding step, it is preferable to apply an insulating resin to a part of the capacitor element 11 prior to bonding the capacitor element 11 to the anode terminal forming portion 21.

  In any case, when the capacitor element 11 is bonded to the lead frame and molded with the exterior resin 19, the anode terminal forming portion 21 and the cathode terminal forming portion 22 are formed as shown in FIG. The surface recess 24a and the cathode side fillet surface recess 24b perform a cutting process along the anode side cut surface 23a and the cathode side cut surface 23b to obtain a chip body, thereby forming a fillet surface after cutting. Also in this process, the anode terminal forming part 21 and the cathode terminal forming part 22 are characterized in that a plating process is not necessary after cutting by providing a plated recess.

  Incidentally, here, after producing a flat lead frame, the anode terminal forming portion 21 and the cathode terminal forming portion 22 are respectively formed with recesses in the shape as shown in FIG. Regarding the bonding of the element 11, the capacitor element 11 and the anode lead wire 12 are connected by laser welding or resistance welding on the anode side, and the cathode side is connected by the conductive adhesive 20 containing Ag, and the exterior resin 19 is transferred. After molding with a mold, the bottom electrode type solid electrolytic capacitor according to Example 1 was obtained by cutting the two surfaces of the anode side cut surface 23a and the cathode side cut surface 23b, which are product side surfaces, with a dicing saw. In addition, since a known technique can be introduced for the production of the capacitor element 11, a case where tantalum is used as a valve action metal with the details being simplified will be described. When the capacitor element 11 is manufactured, first, a tantalum powder is molded around a tantalum wire with a press machine and then sintered at a high vacuum / high temperature, and then a Ta2O5 oxide film is formed on the surface of the tantalum metal powder. A step of immersing in manganese nitrate and further thermally decomposing to form MnO 2 and then forming a cathode layer of graphite and Ag to obtain the capacitor element 11 may be executed. However, a conductive polymer such as polythiophene or polypyrrole can be used instead of MnO 2 for forming the cathode layer. In this case, it is easy to obtain a low ESR as one capacitor element 11. In addition to tantalum, niobium, aluminum, titanium or the like can be used as the valve metal.

  Note that the bottom electrode type solid electrolytic capacitor according to Example 1 described above is merely disclosed as an example, and the detailed structure in each part can be variously modified and modified by design change. The lead frame of the invention, the manufacturing method of the bottom electrode type solid electrolytic capacitor using the same, and the bottom electrode type solid electrolytic capacitor manufactured thereby are not limited to those disclosed in the first embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It shows the basic structure of the bottom electrode type solid electrolytic capacitor according to Example 1 of the present invention, (a) relates to a side view from the anode side, (b) shows a part of the exterior resin from the front side. (C) relates to the side view from the cathode side. FIG. 2 is a front view illustrating a state before cutting in which a capacitor element is joined to a lead frame provided in the bottom electrode type solid electrolytic capacitor illustrated in FIG. It is the flowchart which showed the manufacturing process of the bottom electrode type solid electrolytic capacitor shown in FIG. 1 illustrates a basic structure of a bottom electrode type solid electrolytic capacitor according to a premise technique of the present invention, wherein (a) relates to a side view from the anode side, and (b) illustrates a front view seen through from the front side. (C) relates to a side view from the cathode side. FIG. 5 is a front view showing a state before cutting in which a capacitor element is bonded to a lead frame provided in the bottom electrode type solid electrolytic capacitor shown in FIG.

Explanation of symbols

11, 71 Capacitor element 12, 72 Anode lead wire 13, 73 Anode terminal 14, 74 Cathode terminal 15a, 76a Anode fillet surface 15b, 76b Cathode side fillet surface 16, 79 Anode terminal cut surface 17 Reference surface 18, 78 Cathode terminal Cut surface 19, 99 Exterior resin 20, 80 Conductive adhesive 21, 81 Anode terminal forming part 22, 82 Cathode terminal forming part 23a, 83a Anode side cut surface 23b, 83b Cathode side cut surface 24a, 84a For anode fillet surface Recesses 24b, 84b Cathode side fillet surface recesses 25a Anode side projections 25b Cathode side projections 26 Inclined surfaces 77 Insulating resin

Claims (10)

  In a lead frame for forming a terminal used for manufacturing a bottom electrode type solid electrolytic capacitor having an electrode directly drawn to the substrate mounting side, an anode terminal forming portion for forming an anode terminal and a cathode terminal for forming a cathode terminal The anode terminal forming portion is partly deformed in a direction perpendicular to the mounting surface to form a concave portion on the mounting surface side, and a convex portion on the opposite side to the mounting surface. A portion is formed, the concave portion is plated, and the convex portion is parallel to the mounting surface and is connected to the flat portion and becomes closer to the mounting surface as it is connected to the flat portion and away from the flat portion. And a connection end in which the connection range for connecting the cathode terminal and the capacitor element with a conductive adhesive is in the anode lead wire embedded surface portion of the capacitor element. Lead frame, characterized in that the cathode side portions are positioned to extend in the reference surface portion close as reference surface.   2. The lead frame according to claim 1, wherein the cathode terminal is configured to expose part or all of the cathode terminal on the mounting surface according to the connection range extending from the cathode side portion toward the reference surface side portion. A lead frame characterized by being connected by an adhesive.   3. The lead frame according to claim 1, wherein the concavo-convex portion is formed by drawing or coining.   The lead frame according to any one of claims 1 to 3, wherein the cross-sectional shape parallel to the mounting surface in the concave portion is a polygonal shape or a shape having at least one side as a straight line. Lead frame.   The lead frame according to any one of claims 1 to 4, wherein a surface substantially perpendicular to the mounting surface of the convex portion is directed in a direction parallel to the mounting surface from the mounting surface. A lead frame provided with a protrusion or a notch at a distant position.   6. The lead frame according to claim 1, wherein the anode terminal forming portion and the cathode terminal forming portion include Ag, Au, Cu, Pd for forming the anode terminal and the cathode terminal, respectively. A lead frame, wherein a film containing at least one of Sn and Sn is formed.   7. The lead frame according to claim 1, wherein the anode terminal and the cathode terminal are formed on surfaces of the anode terminal forming portion and the cathode terminal forming portion in the frame thickness direction, respectively. Therefore, a lead frame in which a film containing at least one of Ag, Au, Cu, Pd, and Sn is formed.   A method for manufacturing a bottom electrode type solid electrolytic capacitor using the lead frame according to any one of claims 1 to 7, wherein a capacitor joining step for joining the capacitor element on the lead frame, and the capacitor element And a resin molding step of molding the lead frame with an exterior resin, while leaving one of the plated surfaces along one of the plated surfaces of the recess, the lead frame, the anode lead wire of the capacitor element, and The manufacturing method of the bottom electrode type solid electrolytic capacitor characterized by including the outer surface formation process which cuts said exterior resin and forms the outer surface used as the side of a product.   9. The method of manufacturing a bottom electrode type solid electrolytic capacitor according to claim 8, wherein in the capacitor joining step, the capacitor element is joined to the anode terminal forming portion, and a part of the anode terminal forming portion is joined prior to the joining. A method of manufacturing a bottom electrode type solid electrolytic capacitor, comprising applying an insulating resin. 10. A bottom electrode type solid electrolytic capacitor manufactured by the method of manufacturing a bottom electrode type solid electrolytic capacitor according to claim 8 or 9, wherein the capacitor element is a porous metal made of a valve action metal from which the anode lead wire is led out. A dielectric layer, an electrolyte layer, and a cathode layer are sequentially formed on the surface of the sintered body. One end of the anode terminal formed in the anode terminal forming portion is connected to the anode lead wire. The other end is provided as an external connection terminal. The cathode terminal formed in the cathode terminal forming portion is connected at one end to the cathode layer in the capacitor element, and the other end is external. The exterior resin covers the capacitor element and has an exposed surface on a mounting surface of the anode terminal and the cathode terminal with respect to the substrate and an outer surface substantially perpendicular to the mounting surface. Lower-face electrode type solid electrolytic capacitor characterized in that it is intended to be exterior to.

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