JP5164213B2 - Solid electrolytic capacitor - Google Patents

Description

  The present invention relates to a small-sized and large-capacity solid electrolytic capacitor excellent in reliability and used for stabilizing a power supply voltage of electronic equipment and reducing high-frequency noise.

  In recent years, with the increase in performance of electronic devices, the circuit drive frequency has been increased. In order to cope with this, it is important to smooth the power supply voltage and prevent high frequency noise. Compared to conventional aluminum electrolytic capacitors using electrolytic solution and tantalum capacitors using manganese dioxide as solid electrolyte, equivalent series resistance (ESR) A solid electrolytic capacitor using a conductive polymer as a solid electrolyte that can be greatly reduced) has been used.

  In addition, along with the downsizing and thinning of electronic devices, the demand for downsizing and thinning of electronic components has increased, and the demand for solid electrolytic capacitors that are small and thin, low impedance, and large capacity has increased.

7A and 7B are diagrams illustrating a conventional solid electrolytic capacitor. FIG. 7A is a plan view of an electrode substrate, FIG. 7B is a cross-sectional view taken along the line DD in FIG. 7A, and FIG. ) Shows a schematic cross-sectional view of the solid electrolytic capacitor. The solid electrolytic capacitor 30 is obtained by mounting the capacitor element 17 on the electrode substrate 18, thermocompression bonding the capacitor element 17 through the conductive adhesive 19, and then molding with the exterior resin 20.
Patent Document 1 describes a large-capacity multilayer solid electrolytic capacitor in which capacitor elements made of plate-like aluminum are stacked and connected to an electrode substrate via a conductive adhesive.

JP 2008-28298 A

  To achieve small size, thinness, low impedance, and large capacity, the distance from the end of the capacitor element in the capacitor package to the package surface (hereinafter referred to as the exterior margin) is reduced to increase the volume efficiency of the capacitor element. However, there is a problem that reliability is reduced due to intrusion of moisture.

  In particular, when the exterior resin is a general mold resin in a product with a structure that combines the exterior resin and the electrode substrate, it is necessary to ensure the releasability from the mold mold, so that a certain degree of releasability is imparted to the resin. Has been. As a result, the adhesive force between the resin and the electrode substrate is essentially reduced, and moisture easily enters from the interface between the exterior resin and the electrode substrate. Since the moisture resistance reliability is low, the exterior margin cannot be reduced, which hinders downsizing.

  The present invention solves the above-mentioned problems, and is a thin solid electrolytic capacitor made of a plate-like or foil-like valve metal, which has high moisture resistance reliability, can be realized in a small, thin, low impedance, and large capacity. It is to provide a capacitor.

  In order to solve the above-mentioned problem, the present invention provides moisture that permeates from the interface between the exterior resin and the electrode substrate by providing a convex portion or a concave portion in the peripheral portion of the cathode terminal formed on the capacitor element mounting surface of the electrode substrate. Thus, a solid electrolytic capacitor can be obtained that can maintain excellent moisture resistance reliability even when the penetration path of the capacitor is made long and the exterior margin for increasing the volume efficiency of the capacitor element is reduced.

According to the present invention, a dielectric layer made of an oxide of the valve action metal is formed on the enlarged surface of a base material made of a plate-like or foil-like valve action metal, and the dielectric layer is formed on the dielectric layer. A capacitor element in which a cathode conductor part including a solid electrolyte layer is formed and an anode conductor part made of the valve metal separated from the cathode conductor part and an insulating part is formed; and an electrode substrate on which the capacitor element is mounted A solid electrolytic capacitor in which the capacitor element is bonded to the electrode substrate via a conductive adhesive and sealed with an exterior resin, and is formed on the mounting surface of the capacitor element of the electrode substrate anode terminals for connecting the anode conductor portion and the peripheral portion of the cathode terminal for connecting the cathode conductor portion, said anode terminal and said cathode terminal so as to surround both the convex of the same material as the anode terminal and the cathode terminal a little part Solid electrolytic capacitor being characterized in that also one form is obtained.

According to the present invention, the sectional shape of the convex portion has an upper surface side is the convex portion, the above-mentioned solid electrolytic capacitor characterized in that each larger than the surface side of the electrode substrate is obtained.

According to the present invention, the sectional shape of the convex portion, the minimum thickness of the convex portion, and the upper surface of the convex portion, the above-mentioned solid electrolytic capacitor and is smaller than the surface side of the electrode substrate is obtained It is done.

According to the present invention, the sectional shape of the convex portion, the maximum thickness of the convex portion, and the upper surface of the convex portion, the above-mentioned solid electrolytic capacitor being larger than the surface side of the electrode substrate is obtained It is done.

  In the present invention, by providing a convex portion or a concave portion in the peripheral portion of the cathode terminal formed on the capacitor element mounting surface of the electrode substrate, the ingress path of moisture entering from the interface between the exterior resin and the electrode substrate becomes long, and the capacitor Even when the exterior margin for increasing the volumetric efficiency of the element is reduced, excellent moisture resistance reliability can be realized.

  Further, the cross-sectional shape of the convex portion or the concave portion is such that the upper surface side of the convex portion or the bottom surface side of the concave portion is larger than the surface side of the electrode substrate, or the minimum thickness of the convex portion or the minimum width of the concave portion is the upper surface side of the convex portion. Alternatively, the bottom surface side of the concave portion and the shape smaller than the surface side of the electrode substrate, or the maximum thickness of the convex portion or the maximum width of the concave portion is larger than the upper surface side of the convex portion or the bottom surface side of the concave portion and the surface side of the electrode substrate. By adopting the shape, it is possible to further increase the intrusion route of moisture that penetrates along the interface between the exterior resin and the electrode substrate, and it is also possible to improve the adhesive strength between the exterior resin and the electrode substrate due to the anchor effect. .

  Embodiments according to the present invention will be described with reference to the drawings.

  1A and 1B are diagrams illustrating an electrode substrate in a solid electrolytic capacitor according to the present invention. FIG. 1A is a plan view, FIG. 1B is a cross-sectional view taken along line AA in FIG. ) Shows enlarged sectional views in a circle X of FIG. 2A and 2B are diagrams for explaining the solid electrolytic capacitor of the present invention. FIG. 2A is a schematic cross-sectional view of the capacitor element, and FIG. 2B is a schematic cross-sectional view of the solid electrolytic capacitor.

  As shown in FIG. 1, the electrode substrate 18 has an element-side anode terminal 11 and an element-side cathode terminal 12 formed on the capacitor element mounting surface of the base material 10, and a protrusion 13 formed around the element-side anode terminal 11. . On the other hand, the external anode terminal 14 and the external cathode terminal 15 are formed on the mounting surface of the electrode substrate 18, the element side anode terminal 11 and the external anode terminal 14, and the element side cathode terminal 12 and the external cathode terminal 15 respectively. The structure is connected by vias 16.

  The convex portion 13 is for improving the moisture resistance reliability by lengthening the penetration path when moisture enters from the interface between the exterior resin 20 and the electrode substrate 18 shown in FIG. Any of resin, metal and the like may be used. Further, the convex portion 13 is formed by chemical etching simultaneously with the element side anode terminal 11 and the element side cathode terminal 12. Furthermore, as shown in FIG.1 (c), the cross-sectional shape is made into the substantially rectangular shape.

  On the other hand, as shown in FIG. 2 (a), the capacitor element 17 is preferably an aluminum foil in which both surfaces of the aluminum foil that is the valve metal 1 are enlarged by an etching process and an oxide film 2 is formed by anodization. The element size is cut out. Next, an insulating portion 3 made of an insulating resin such as an epoxy resin is applied and formed at a predetermined position on the oxide film 2, and the aluminum foil is divided into regions of the anode conductor portion 8 and the cathode conductor portion 9. Thereafter, anodic oxidation is performed again, and an oxide film is re-formed on a portion where the aluminum core is exposed, such as a cut surface. Subsequently, a solid electrolyte layer 4 made of a conductive polymer, a graphite layer 5, and a metal electrode layer 6 made of a conductive paste or the like are sequentially laminated and formed on the upper and lower surfaces of the region where the cathode conductor portion 9 is formed. The conductor portion 9 is used.

  Next, in a region other than the cathode conductor portion 9, the oxide film 2 and the surface enlargement layer are removed to expose the aluminum valve metal 1. Further, a lead frame 7 made of Cu or Cu alloy foil plated with Ni, Cu, Ag or the like is joined to the valve metal 1 by ultrasonic welding, resistance welding, laser welding, or the like, To do.

  Next, as shown in FIG. 2 (b), the capacitor element 17 is bonded to the electrode substrate 18 shown in FIG. 1 through a conductive adhesive 19 containing silver or the like, and then an epoxy resin or the like. The exterior resin 20 is used for exterior molding to obtain a solid electrolytic capacitor 30a.

  3A and 3B are diagrams for explaining an electrode substrate in the solid electrolytic capacitor of the present invention. FIG. 3A is a plan view, FIG. 3B is a cross-sectional view taken along the line BB in FIG. ) Respectively show enlarged sectional views in the circle Y of FIG. 4A and 4B are diagrams for explaining the solid electrolytic capacitor of the present invention. FIG. 4A is a schematic sectional view of the capacitor element, and FIG. 4B is a schematic sectional view of the solid electrolytic capacitor.

  As shown in FIG. 3, the electrode substrate 18 has an element-side anode terminal 11 and an element-side cathode terminal 12 formed on the capacitor element mounting surface of the base material 10, and a protrusion 13 formed around the element-side anode terminal 11. . On the other hand, the external anode terminal 14 and the external cathode terminal 15 are formed on the mounting surface of the electrode substrate 18, the element side anode terminal 11 and the external anode terminal 14, and the element side cathode terminal 12 and the external cathode terminal 15 respectively. The structure is connected by vias 16.

  The convex part 13 is for improving the moisture resistance reliability by lengthening the penetration path when moisture enters from the interface between the exterior resin 20 and the electrode substrate 18 shown in FIG. Any of resin, metal and the like may be used. The convex portion 13 is formed by chemical etching simultaneously with the element-side anode terminal 11 and the element-side cathode terminal 12, and the cross-sectional shape of the convex portion 13 is further increased by side etching as shown in FIG. The upper surface side is larger than the surface side of the electrode substrate, and the inner surface is recessed in an arc shape. By setting it as such a cross-sectional shape, the penetration | invasion path | route of the water | moisture content which penetrate | invades along the interface of exterior resin and an electrode board | substrate can further be lengthened, and adhesion | attachment of exterior resin 20 and the electrode board | substrate 18 is possible by an anchor effect. The strength can be further improved.

  On the other hand, as shown in FIG. 4 (a), the capacitor element 17 is preferably an aluminum foil in which both surfaces of the aluminum foil that is the valve metal 1 are enlarged by an etching process and an oxide film 2 is formed by anodization. The element size is cut out. Next, an insulating portion 3 made of an insulating resin such as an epoxy resin is applied and formed at a predetermined position on the oxide film 2, and the aluminum foil is divided into regions of the anode conductor portion 8 and the cathode conductor portion 9. Thereafter, anodic oxidation is performed again, and an oxide film is re-formed on a portion where the aluminum core is exposed, such as a cut surface. Subsequently, a solid electrolyte layer 4 made of a conductive polymer, a graphite layer 5, and a metal electrode layer 6 made of a conductive paste or the like are sequentially laminated and formed on the upper and lower surfaces of the region where the cathode conductor portion 9 is formed. The conductor portion 9 is used.

  Next, in a region other than the cathode conductor portion 9, the oxide film 2 and the surface enlargement layer are removed to expose the aluminum valve metal 1. Further, a lead frame 7 made of Cu or Cu alloy foil plated with Ni, Cu, Ag or the like is joined to the valve metal 1 by ultrasonic welding, resistance welding, laser welding, or the like, To do. This is the same as FIG.

  Next, as shown in FIG. 4 (b), the capacitor element 17 is bonded to the electrode substrate 18 shown in FIG. 3 through a conductive adhesive 19 containing silver or the like, and then an epoxy resin or the like. The exterior resin 20 is used for exterior packaging to obtain a solid electrolytic capacitor 30b.

  5A and 5B are diagrams for explaining an electrode substrate in the solid electrolytic capacitor of the present invention. FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view taken along the line C-C in FIG. 6A and 6B are diagrams for explaining the solid electrolytic capacitor of the present invention. FIG. 6A shows a schematic cross-sectional view of the capacitor element, and FIG. 6B shows a schematic cross-sectional view of the solid electrolytic capacitor.

As shown in FIG. 5, the electrode substrate 18 has an element-side anode terminal 11 and an element-side cathode terminal 12 formed on the capacitor element mounting surface of the base material 10, and two recesses 21 formed on the periphery thereof. ing.
On the other hand, the external anode terminal 14 and the external cathode terminal 15 are formed on the mounting surface of the electrode substrate 18, the element side anode terminal 11 and the external anode terminal 14, and the element side cathode terminal 12 and the external cathode terminal 15 respectively. The structure is connected by vias 16.

The concave portion 21 is provided to lengthen the penetration path when moisture enters from the interface between the exterior resin 20 and the electrode substrate 18 shown in FIG. The capacitor element mounting surface is formed by laser processing or the like. The cross-sectional shape of the recess 21 is substantially rectangular as shown in FIG. 5B, but the bottom surface side of the recess 21 is larger than the surface side of the electrode substrate, or the minimum width of the recess 21 is the bottom surface side of the recess 21. And a shape smaller than the surface side of the electrode substrate, that is, a shape having a minimum width portion between the electrode substrate surface and the bottom surface of the recess, or a maximum width of the recess 21 is set on the bottom surface side of the recess 21 and the electrode substrate. A shape larger than the surface side, that is, a shape in which a portion having the maximum width is located between the electrode substrate surface and the bottom surface of the recess may be employed. By adopting such a cross-sectional shape, it is possible to further increase the intrusion route of moisture that penetrates along the interface between the exterior resin and the electrode substrate, and the anchor effect also improves the adhesive strength between the exterior resin and the electrode substrate. Can be made.
In addition, the depth of the recess 21 is preferably about ½ or less of the thickness of the base material 10 in order to maintain the strength of the electrode substrate 18. Further, a plurality of recesses 21 may be formed.

  On the other hand, as shown in FIG. 6 (a), the capacitor element 17 is preferably an aluminum foil in which both surfaces of the aluminum foil that is the valve metal 1 are expanded by an etching process and an oxide film 2 is formed by anodization. The element size is cut out. Next, an insulating portion 3 made of an insulating resin such as an epoxy resin is applied and formed at a predetermined position on the oxide film 2, and the aluminum foil is divided into regions of the anode conductor portion 8 and the cathode conductor portion 9. Thereafter, anodic oxidation is performed again, and an oxide film is re-formed on a portion where the aluminum core is exposed, such as a cut surface. Subsequently, a solid electrolyte layer 4 made of a conductive polymer, a graphite layer 5, and a metal electrode layer 6 made of a conductive paste or the like are sequentially laminated and formed on the upper and lower surfaces of the region where the cathode conductor portion 9 is formed. The conductor portion 9 is used.

  Next, in a region other than the cathode conductor portion 9, the oxide film 2 and the surface enlargement layer are removed to expose the aluminum valve metal 1. Further, a lead frame 7 made of Cu or Cu alloy foil plated with Ni, Cu, Ag or the like is joined to the valve metal 1 by ultrasonic welding, resistance welding, laser welding, or the like, To do. This is the same as FIGS. 2 (a) and 4 (a).

  Next, as shown in FIG. 6 (b), the capacitor element 17 is bonded to the electrode substrate 18 shown in FIG. 5 through a conductive adhesive 19 containing silver or the like, and then an epoxy resin or the like. The exterior resin 20 is used for exterior molding to obtain a solid electrolytic capacitor 30c.

  As the valve metal 1 serving as a base material shown in the series of embodiments, it is preferable to use a metal plate or foil such as aluminum, tantalum, niobium or titanium.

  The oxide film 2 acts as a dielectric, and is formed on the metal surface by immersing the valve metal 1 in an electrolytic solution and flowing an electric current. It is preferable to form a film by appropriately adjusting the type and current of the electrolyte.

  The insulating part 3 is made of a material having high heat resistance, and may be any one of a thermosetting resin such as epoxy and silicone, and a thermoplastic resin such as polyimide, and it is preferable to use a paste or liquid. In consideration of film processability, a silicone-based thermosetting resin is more preferable. As a forming method, a general method such as dipping, spraying, coating, or printing is used, and the thickness is preferably 10 to 30 μm, which is sufficient to ensure the function of the resist.

  The solid electrolyte layer 4 is preferably made of a conductive polymer such as polythiophene or polypyrrole.

  The graphite layer 5 is for enhancing the bonding between the metal electrode layer 6 laminated on the upper layer and the solid electrolyte layer 4 formed on the lower layer.

  The metal electrode layer 6 is preferably formed by applying a silver paste generally used as a cathode electrode material of the capacitor element 17 with a dispenser and drying and curing.

  The lead frame 7 is preferably made of a conductive material made of metal such as copper, aluminum, stainless steel, or an alloy thereof, and further having its surface plated with gold, silver, tin, nickel or the like.

  The substrate 10 is preferably made of a highly heat-resistant insulating material, and any of a resin system such as a glass epoxy material, a BT resin, a polyimide, a liquid crystal polymer, or a ceramic system such as alumina may be used. It is more preferable to use a general-purpose glass epoxy material that is effective in terms of flexibility and cost.

  The element-side anode terminal 11 and the element-side cathode terminal 12 are generally used for gravure printing, screen printing, and the like after a conductive foil body made of metal such as copper or aluminum is bonded to the upper surface of the substrate 10. The resist is printed by a simple printing method and is formed by etching. Not only the above method but also a conductive paste may be printed.

The convex part 13 should just be formed in the peripheral part so that the whole of the element side anode terminal 11 and the element side cathode terminal 12 may be enclosed, and a material may be either metal, resin, or those mixed materials. At the time of formation, since it is advantageous in terms of man-hours and costs to be performed simultaneously with the element side anode terminal 11 and the element side cathode terminal 12, the same material as the element side anode terminal 11 and element side cathode terminal 12 is used. It is preferable to perform a resist (insulation) treatment.
The shape of the convex portion 13 as viewed from the upper surface of the electrode substrate 18 may be any of a square shape, a circular shape, an elliptical shape, and the like. It is more preferable to provide a defect portion in the vicinity of the four corners of the electrode substrate 18 where the distance from the outer peripheral end of the substrate 18 to the cathode terminal of the capacitor element, that is, the moisture intrusion path is relatively long.
Moreover, although the cross-sectional shape of the convex part 13 is substantially rectangular in the case shown in FIG. 1 (c), as shown in FIG. 3 (c), the upper surface side of the convex part 13 is the surface side of the electrode substrate by side etching. A larger shape, that is, an inverted trapezoidal shape, or a shape in which the minimum thickness of the convex portion 13 is smaller than the upper surface side of the convex portion 13 and the surface side of the electrode substrate 18, that is, the side surface is recessed in an arc shape or a wedge shape. By forming an elliptical shape or a shape where the maximum thickness of the convex portion 13 is larger than the upper surface side of the convex portion 13 and the surface side of the electrode substrate 18, that is, a shape in which the side surface protrudes outward in an arc shape or a wedge shape, The intrusion path of moisture entering along the interface between the exterior resin 20 and the electrode substrate 18 can be further lengthened, and the adhesive strength between the exterior resin 20 and the electrode substrate 18 can be improved by the anchor effect.

  The external anode terminal 14 and the external cathode terminal 15 are formed by attaching a conductive foil made of metal such as copper or aluminum to the lower surface of the base material 10 and attaching it to general printing such as gravure printing or screen printing. Resist printing is performed by a construction method, and it is formed by etching. Not only the above method but also a conductive paste may be printed.

  The electrode substrate 18 includes the base material 10, the element-side anode terminal 11, the element-side cathode terminal 12, the external anode terminal 14 and the external cathode terminal 15 formed on the upper and lower surfaces thereof, and vias 16 that join them together. It has been done.

  The conductive adhesive 19 is preferably applied by using a dispenser with an epoxy-based paste resin containing metal powder such as gold, silver or copper.

  The exterior resin 20 is a general-purpose sealing resin and may be any resin that can withstand the use environment, such as an epoxy-based or phenol-based thermosetting resin, polypropylene (PP), polystyrene (PS), or the like. Any of thermoplastic resins may be used, but it is preferable to select them appropriately in consideration of heat resistance and workability. In consideration of solder reflow mounting property on the power supply board, an epoxy-based thermosetting resin is more preferable. The sealing method may be any method such as an injection method or a transfer method.

The recess 21 is for increasing the moisture penetration reliability by increasing the penetration path when moisture enters from the interface between the exterior resin 20 and the electrode substrate 18. 11 and the element-side cathode terminal 12 are formed around the periphery by an etching method or the like. The shape of the concave portion 21 viewed from the upper surface of the electrode substrate 18 may be any of a square shape, a circular shape, and an elliptical shape, and is not limited to an annular shape, and may be in a state without a partial concave portion. More preferably, the distance from the outer peripheral edge of the capacitor 18 to the cathode terminal of the capacitor element, that is, the location where there is no recess in the vicinity of the four corners of the electrode substrate 18 where the water infiltration path is relatively long.
In addition, the cross-sectional shape of the concave portion 21 is substantially rectangular in the case shown in FIG. 5C, but the inner surface may be formed in an arc shape or a wedge shape inwardly or projecting outwardly. By doing so, the intrusion route of moisture entering along the interface between the exterior resin 20 and the electrode substrate 18 can be further lengthened, and the adhesive strength between the exterior resin 20 and the electrode substrate 18 is improved by the anchor effect. Can be made.
The number to be formed is preferably 1 or more, and is suitably adjusted according to the gap and groove width to the outer peripheral edge of the electrode substrate 18. Increasing the number makes it possible to lengthen the moisture intrusion route, which is favorable in terms of moisture resistance reliability. However, it is difficult to increase the number of grooves when the gap is reduced due to downsizing, and thus it is preferable to adjust appropriately.
The depth of the recess 21 is preferably about ½ of the thickness of the base material 10 in view of the strength of the electrode substrate 18.

  In addition, you may form the convex part 13 and the recessed part 21 mentioned above in combination on the upper surface of the base material 10 suitably.

  Hereinafter, it explains in full detail using an Example.

Example 1
As the capacitor element 17 used in the solid electrolytic capacitor of the present invention, first, a porous portion was formed on the surface of the thin plate-like valve metal 1 to enlarge the surface, and anodized to form the oxide film 2. Here, an aluminum foil having a capacitance of 450 μF per unit square centimeter, a nominal formation voltage of 3 V for forming an oxide film, and a thickness of 150 μm was selected, which is commercially available for aluminum electrolytic capacitors. This aluminum foil was cut into a shape having a width of 2.6 mm and a length of 5.4 mm, and a region having a width of 2.6 mm and a length of 4.4 mm from the end in the length direction of the aluminum foil was defined as a cathode formation portion, A region having a width of 2.6 mm and a length of 0.5 mm from the end in the length direction of the aluminum foil was defined as an anode forming portion.

  Subsequently, as the insulating portion 3 for separating the anode and the cathode, a resin mainly composed of an epoxy resin is used, and the width is 2.6 mm and the length is 0.65 mm from the anode forming portion side lengthwise end portion. It was formed by coating and curing at a thickness of 0.3 mm and a thickness of 20 μm. After the formation of the insulating part 3, it was immersed in a 10% aqueous solution of diammonium adipate and a voltage of 5V was applied for 30 minutes to form an oxide film again on the exposed aluminum part.

  Next, 3,4-ethylenedioxythiophene as a monomer, ammonium peroxodisulfate as an oxidant, and paratoluenesulfonic acid as a dopant at a composition ratio of 6: 1: 2 on the oxide film 2 of the cathode forming portion. A solid electrolyte layer 4 made of a reacted conductive polymer was formed, and a graphite layer 5 having a thickness of 15 μm was formed thereon by screen printing. Further, a conductive paste containing silver was applied on the graphite layer 5 to a thickness of 25 μm, and dried and cured at 150 ° C. to form the metal electrode layer 6, thereby forming the cathode conductor portion 9. Thereafter, the oxide film 2 in the anode forming portion is removed, and a lead frame 7 made of Cu alloy foil having a width of 2.6 mm, a length of 0.5 mm, and a thickness of 80 μm plated with Ni is formed on the lower surface of the anode conductor portion 8. The capacitor element 17 shown in FIG. 2A was obtained by ultrasonic welding.

  Next, as the electrode substrate 18, an FR-4 material having a base material 10 with a thickness of 100 μm is used. The cathode terminal 12 was formed of a copper foil having a thickness of 50 μm by a chemical etching method, and a convex portion 13 of a copper foil having a width of 100 μm and a height of 60 μm was formed in a rectangular shape around the periphery thereof. On the other hand, the external anode terminal 14 and the external cathode terminal 15 are formed on the mounting surface of the substrate 10 with a copper foil having a thickness of 50 μm, and the element side anode terminal 11 and the external anode terminal 14 and the element side cathode terminal 12 and the external side are externally formed. The cathode terminal 15 was joined to each other through the via 16 to obtain the electrode substrate 18 shown in FIG.

  Next, as shown in FIG. 2 (b), a conductive adhesive 19 made of a silver-containing epoxy adhesive is screen-printed on the upper surfaces of the element-side anode terminal 11 and the element-side cathode terminal 12 of the electrode substrate 18. The capacitor element 17 was thermocompression bonded by coating with a thickness of 70 μm. Subsequently, transfer molding was performed with the exterior resin 20 mainly composed of an epoxy resin to obtain the solid electrolytic capacitor 30a of the present invention shown in FIG.

(Example 2)
As Example 2 of the solid electrolytic capacitor of the present invention, the shape, dimensions, configuration and manufacturing method are the same as those of the solid electrolytic capacitor described in Example 1 above, but only the electrode substrate 18 is different. The electrode substrate 18 shown in FIG. The thing using was produced.

The electrode substrate 18 shown in FIG. 3 differs in the cross-sectional shape of the convex part 13 in Example 1. FIG. The convex portion 13 is a copper foil having a width of 100 μm and a height of 60 μm formed by chemical etching at a position 0.15 mm from the outer peripheral ends of the element-side anode terminal 11 and the element-side cathode terminal 12 on the capacitor element mounting surface of the substrate 10. The convex portion 13 was formed in a rectangular shape, and further, by side etching, the cross-sectional shape of the convex portion 13 was changed to an inverted trapezoidal shape that was wider on the surface side than on the substrate side. On the other hand, the external anode terminal 14 and the external cathode terminal 15 are formed with a thickness of 50 μm on the mounting surface of the electrode substrate 18, and the element side anode terminal 11 and the external anode terminal 14, and the element side cathode terminal 12 and the external cathode terminal 15. Were joined via vias 16 respectively.
The capacitor element 17 was mounted on the upper surface of the electrode substrate 18 by the same manufacturing method as in Example 1 to obtain the solid electrolytic capacitor 30b of the present invention shown in FIG. 4B.

(Example 3)
As Example 3 of the solid electrolytic capacitor of the present invention, the shape, dimensions, configuration, and manufacturing method are the same as those of the solid electrolytic capacitor described in Example 1 above, but only the electrode substrate 18 is different. The electrode substrate 18 shown in FIG. The thing using was produced.

The electrode substrate 18 shown in FIG. 5 has a concave portion 21 formed in place of the convex portion 13 in the first and second embodiments. The concave portion 21 is formed on the capacitor element mounting surface of the substrate 10 by laser processing at positions of 0.09 mm and 0.18 mm from the outer peripheral ends of the element-side anode terminal 11 and the element-side cathode terminal 12, and has a width of 60 μm and a depth. Two rectangular shapes with a cross-sectional shape of approximately 50 μm were formed. On the other hand, the external anode terminal 14 and the external cathode terminal 15 are formed to a thickness of 50 μm on the mounting surface of the electrode substrate 18, and the element side anode terminal 11 and the external anode terminal 14, and the element side cathode terminal 12 and the external cathode terminal 15 Were joined via vias 16 respectively.
The capacitor element 17 was mounted on the upper surface of the electrode substrate 18 by the same manufacturing method as in Example 1 to obtain the solid electrolytic capacitor 30c of the present invention shown in FIG. 6B.

(Comparative example)
As a comparative example, a conventional solid electrolytic capacitor using the electrode substrate 18 having the same shape, dimensions, configuration, and manufacturing method as those of Examples 1 to 3 but without the convex portion 13 or the concave portion 21 shown in FIG. Was made.

  The solid electrolytic capacitors according to Examples 1 to 3 and the comparative example were each placed in a constant temperature and humidity chamber of 65 ° C. and 95% RH at n = 10, and the humidity resistance reliability was compared by performing a standing test for 500 hours. It was. Table 1 shows the average value of the equivalent series resistance (ESR) at 100 kHz before and after the standing test.

  It can be seen that in the solid electrolytic capacitors of Examples 1 to 3 according to the present invention, the equivalent series resistance (ESR) change before and after the standing test is small and the moisture resistance reliability is improved as compared with the solid electrolytic capacitor of the comparative example. .

  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.

  With the solid electrolytic capacitor of the present invention, it is possible to reduce the size, increase the capacity, improve the performance, and improve the quality, and respond to the increasingly diverse electronic equipment market where demands for further downsizing and higher performance become stricter in the future. Become.

FIG. 1A is a plan view, FIG. 1B is a cross-sectional view taken along line AA in FIG. 2A, and FIG. 1C is a diagram illustrating an electrode substrate in a solid electrolytic capacitor of the present invention. The expanded sectional view in the circle | round | yen X of (b). The figure explaining the solid electrolytic capacitor of this invention, Fig.2 (a) is a cross-sectional schematic diagram of a capacitor | condenser element, FIG.2 (b) is a cross-sectional schematic diagram of a solid electrolytic capacitor. FIG. 3A is a plan view, FIG. 3B is a cross-sectional view taken along line BB in FIG. 3A, and FIG. 3C is a diagram illustrating an electrode substrate in the solid electrolytic capacitor of the present invention. The expanded sectional view in the circle Y of (b). The figure explaining the solid electrolytic capacitor of this invention, Fig.4 (a) is a cross-sectional schematic diagram of a capacitor | condenser element, FIG.4 (b) is a cross-sectional schematic diagram of a solid electrolytic capacitor. The figure explaining the electrode substrate in the solid electrolytic capacitor of this invention, Fig.5 (a) is a top view, FIG.5 (b) is CC sectional view taken on the line of Fig.5 (a). The figure explaining the solid electrolytic capacitor of this invention, Fig.6 (a) is a cross-sectional schematic diagram of a capacitor | condenser element, FIG.6 (b) is a cross-sectional schematic diagram of a solid electrolytic capacitor. FIG. 7 (a) is a plan view of an electrode substrate, FIG. 7 (b) is a cross-sectional view taken along the line DD of FIG. 7 (a), and FIG. 7 (c) is a solid electrolytic capacitor. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve metal 2 Oxide film 3 Insulation part 4 Solid electrolyte layer 5 Graphite layer 6 Metal electrode layer 7 Lead frame 8 Anode conductor part 9 Cathode conductor part 10 Base material 11 Element side anode terminal 12 Element side cathode terminal 13 Convex part 14 External Anode terminal 15 External cathode terminal 16 Via 17 Capacitor element 18 Electrode substrate 19 Conductive adhesive 20 Exterior resin 21 Recesses 30, 30a, 30b, 30c Solid electrolytic capacitor

Claims (4)

A dielectric layer made of an oxide of the valve action metal is formed on the surface of the base material made of a plate-like or foil-like valve action metal, and a solid electrolyte layer is included on the dielectric layer A capacitor element formed by forming a cathode conductor part and forming an anode conductor part made of the valve metal separated by the cathode conductor part and the insulating part; and an electrode substrate on which the capacitor element is mounted, the capacitor A solid electrolytic capacitor in which an element is bonded to the electrode substrate via a conductive adhesive and sealed with an exterior resin, and the anode conductor portion formed on the mounting surface of the capacitor element of the electrode substrate is connected anode terminal is, and the periphery of the cathode terminal for connecting the cathode conductor portion, wherein the anode terminal and to surround both the cathode terminal, at least one convex portion of the same material as the anode terminal and the cathode terminal forming did The solid electrolytic capacitor according to claim and. 2. The solid electrolytic capacitor according to claim 1, wherein a cross-sectional shape of the convex portion is such that an upper surface side of the convex portion is larger than a front surface side of the electrode substrate. Cross-sectional shape of the convex portion, the minimum thickness of the convex portion, the solid electrolytic capacitor according to claim 1, characterized in that the upper surface of the convex portion is smaller than the surface side of the electrode substrate. Cross-sectional shape of the convex portion, the maximum thickness of the convex portion, the solid electrolytic capacitor according to claim 1, wherein the upper surface of the convex portion, is greater than the surface side of the electrode substrate.

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