JP2006073638A - Solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor which can reduce an operation failure even if the resist layer of a capacitor element is made thin. <P>SOLUTION: The capacitor element 2 of the solid electrolytic capacitor is provided with an anode 6, a cathode 7 and a resist layer 8 to isolate the anode 6 and the cathode 7 electrically. The anode 6 is formed of the roughening destructive part 9 of an aluminum substrate 9. A solid electrolyte layer 11 is formed in a roughening holding area 9b of the aluminum substrate 9, and a conductor layer 12 forming the cathode 7 is formed on the solid electrolyte layer 11. The resist layer 8 is formed with an internal projected part 15 having an arcuate cross section, and two external projected parts 16 which are formed on both sides of the internal projected part 15 and have arcuate cross sections. A space between the internal projected part 15 and the respective external projected parts 16 forms a recess 17 for liquid accumulation to accumulate a reaction solution that flows toward the anode 6 during the formation of the cathode 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solid electrolytic capacitor including a capacitor element having an anode part and a cathode part.

As a conventional solid electrolytic capacitor, for example, there is one described in Patent Document 1. In the solid electrolytic capacitor described in Patent Document 1, the valve action metal foil is provided with a resist layer including a water repellent resin layer and a hydrophilic resin layer at a predetermined portion of the valve action metal foil. It is divided into a foil part, a chemical oxidation polymerization film is formed on the element foil part, and an electrolytic polymerization film is further formed on the chemical oxidation polymerization film.
JP-A-6-45206

  However, in the above-described prior art, when the resist layer is thin, when the chemical oxidation polymerization film is formed on the element foil portion by the chemical polymerization method, the reaction solution may get over the resist layer and flow into the anode extraction portion. is there. In this case, there is a problem that a leakage current failure of the solid electrolytic capacitor occurs. In order to solve such a problem, it is conceivable to make the resist layer sufficiently thick. By the way, when forming a multilayer solid electrolytic capacitor by laminating a plurality of capacitor elements, it is necessary to bend each anode part in order to connect the anode parts of each capacitor element by laser welding or the like. At this time, if the resist layer is thick, the amount of bending of each anode portion increases accordingly, so that there is a possibility that cracks or disconnection of the anode portion may occur.

  An object of the present invention is to provide a solid electrolytic capacitor capable of reducing malfunction even when the resist layer of the capacitor element is thinned.

  The inventors of the present invention repeatedly conducted experiments on the formation of a capacitor element, and as a result of intensive studies, for example, using a chemical oxidation polymerization method, a solid was formed on the surface of a valve metal substrate partially formed with a resist layer. It has been found that when the electrolyte layer is formed, if the dent is provided in the resist layer, the reaction solution hardly gets over the resist layer even if the resist layer is somewhat thin. The present invention has been made based on such knowledge.

  That is, the present invention is a solid electrolytic capacitor including a capacitor element, the capacitor element being formed on a surface of an anode portion formed in a partial region of the valve metal base and a region excluding the anode portion in the valve metal base. A cathode portion formed by laminating a solid electrolyte layer and a conductor layer; and a resist layer that electrically separates the anode portion and the cathode portion. The resist layer has an anode portion when the cathode portion is formed. A liquid reservoir recess is provided for storing the reaction solution flowing toward it.

  In order to produce a capacitor element in such a solid electrolytic capacitor, first, a resist layer having a recess for collecting liquid is formed on the surface of the region between the anode forming region and the cathode forming region in the valve metal substrate. Then, a cathode part is formed by laminating a solid electrolyte layer and a conductor layer on the surface of the cathode forming region in the valve metal substrate. At this time, for example, when the solid electrolyte layer is formed by the chemical oxidative polymerization method, the reaction solution flows toward the resist layer. However, when the thickness of the resist layer is small, the reaction solution tends to get over the resist layer. However, since the resist layer is provided with a liquid reservoir recess, the reaction solution that has flowed into the resist layer is accumulated in the liquid reservoir recess. For this reason, the reaction solution is prevented from flowing over the resist layer to the anode portion. Thereby, even if the resist layer is somewhat thin, it is possible to reduce malfunction such as a leakage current defect of the solid electrolytic capacitor.

  Preferably, the resist layer includes a first convex portion and a second convex portion that is formed on the cathode portion side with respect to the first convex portion and has a top height position lower than that of the first convex portion. And the recessed part for a liquid pool is formed in the space between a 1st convex part and a 2nd convex part. In this case, for example, when the solid electrolyte layer is formed on the surface of the valve metal substrate by the chemical oxidative polymerization method, the reaction solution that has flowed into the resist layer is accumulated in the liquid reservoir recess beyond the second convex portion. However, it does not flow to the anode part unless it exceeds the first convex part. Here, since the top height position of the first convex portion is higher than the top height position of the second convex portion, the reaction solution cannot easily exceed the first convex portion. Thereby, it can suppress more effectively that a reaction solution gets over an resist part over a resist layer.

  Preferably, the resist layer is formed along a direction in which the anode part and the cathode part are juxtaposed, and has a plurality of convex parts having a cross-sectional mountain shape, and a liquid reservoir concave part is formed in a space between the convex parts. Form. A resist layer having a plurality of convex portions having such cross-sectional mountain shapes can be easily formed by using, for example, a screen printing method.

  According to the present invention, even when the resist layer is made somewhat thin, the reaction solution flowing toward the anode portion is prevented from getting over the resist layer when the cathode portion is formed, thereby reducing the malfunction of the solid electrolytic capacitor. be able to. Accordingly, since the thickness of the resist layer does not need to be increased more than necessary, the bending amount of the anode portion of each capacitor element can be suppressed when forming a multilayer solid electrolytic capacitor in which a plurality of capacitor elements are stacked. . As a result, it is possible to prevent the occurrence of cracks and disconnections in the anode part.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a solid electrolytic capacitor according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of a solid electrolytic capacitor according to the present invention. In the figure, the solid electrolytic capacitor 1 of the present embodiment includes a capacitor element laminate 3 composed of a plurality (three in this case) of capacitor elements 2, and a substrate 4 on which the capacitor element laminate 3 is placed and fixed. And a resin mold part 5 for molding the capacitor element laminate 3. The capacitor element 2 includes an anode part 6, a cathode part 7, and a resist layer 8 that is formed between the anode part 6 and the cathode part 7 and electrically separates the anode part 6 and the cathode part 7. ing.

  2 is a cross-sectional view showing a specific structure of the capacitor element 2, FIG. 3 is a partially enlarged cross-sectional view of FIG. 2, and FIG. 4 is a plan view of the capacitor element 2. In each figure, the anode portion 6 is formed by one end side portion of a foil-like or plate-like aluminum substrate 9 punched into a rectangular shape. The surface of the aluminum substrate 9 is roughened (enlarged) to increase the surface area. An insulating aluminum oxide film (dielectric layer) 10 is formed on the surface of the aluminum substrate 9 by chemical conversion treatment (anodic oxidation).

  One end side region of the aluminum substrate 9 including the region where the anode 6 is formed constitutes a roughened fracture region 9a in which the roughened structure of the surface is destroyed. A solid electrolyte layer 11 containing a conductive polymer compound is formed on the surface (both sides) of the roughened holding region 9b excluding the roughened broken portion 9a in the aluminum substrate 9. The solid electrolyte layer 11 is formed so as to enter the fine hole 9 c formed by roughening the surface of the aluminum substrate 9. On the solid electrolyte layer 11, a conductor layer 12 that forms the cathode portion 7 is provided. The conductor layer 12 is formed by sequentially laminating a graphite paste layer 13 and a silver paste layer 14.

  The resist layer 8 is formed on the surface (both sides) of the base end portion of the roughened fracture region 9a in the aluminum substrate 9. The resist layer 8 extends in a direction perpendicular to the longitudinal direction of the aluminum substrate 9 (the direction in which the anode portion 6 and the cathode portion 7 are arranged in parallel). The resist layer 8 is made of an insulating epoxy resin or the like. The width W of the resist layer 8 is about 0.5 to 1 mm, and the thickness (height) D of the resist layer 8 is about 15 μm, for example.

  The resist layer 8 is formed on the inner convex portion 15 having a cross-sectional mountain shape, and on both sides (the anode portion 6 side and the cathode portion 7 side) of the inner convex portion 15, and has two outer convex portions having a cross-sectional mountain shape. It consists of the shape part 16. The top height position of the outer convex portion 16 is lower than the top height position of the inner convex portion 15. A space is formed between the inner convex portion 15 and each outer convex portion 16 by the inner convex portion 15 and the outer convex portion 16 having a mountain shape in cross section. This space forms a liquid reservoir recess 17 having a substantially V-shaped cross section for storing a reaction solution flowing toward the anode 6 when the cathode 7 is formed. The liquid reservoir recess 17 extends in a direction perpendicular to the longitudinal direction of the aluminum substrate 9.

  In the case of producing such a capacitor element 2, first, a resist layer 8 is formed on the surface of the base end portion of the roughened fracture region 9 a in the aluminum substrate 9 by using a screen printing method.

  Specifically, first, using a screen pattern (not shown) having two linear patterns extending in parallel, two resin layers 18 having a cross-sectional mountain shape are formed as shown in FIG. Form. These resin layers 18 constitute the outer convex portions 16 of the resist layer 8. Subsequently, using a screen pattern (not shown) having a single linear pattern, a resin layer 19 having a cross-sectional mountain shape is formed between the two resin layers 18 as shown in FIG. Form. The resin layer 19 constitutes the inner convex portion 15 of the resist layer 8. At this time, as the screen pattern used for the second time, it is desirable to use a screen pattern having a larger film thickness than the screen pattern used first. As described above, the resist layer 8 having the two liquid reservoir concave portions 17 having a substantially V-shaped cross section is formed.

  Next, a solid electrolyte layer 11 containing a conductive polymer compound is formed on the surface of the roughened holding region 9b in the aluminum substrate 9 (see FIG. 2). Specifically, the solid electrolyte layer 11 is formed by immersing only the roughened holding region 9b in the aluminum substrate 9 in a reaction solution for forming the solid electrolyte layer 11 and performing chemical oxidation polymerization. At this time, for example, a pyrrole or 3,4-ethylenedioxythiophene solution is used as a monomer, and an ethanol water mixed solution containing, for example, sodium alkylnaphthalenesulfonate and iron (III) sulfate is used as an oxidant reaction solution.

  At this time, when the thickness D of the resist layer 8 is small, the reaction solution goes over the resist layer 8 and tries to go to the anode portion 6 side. Therefore, the reaction solution flowing toward the anode portion 6 is collected in the liquid reservoir recess portion 17. Moreover, since the top of the inner convex portion 15 of the resist layer 8 is at a higher position than the top of the outer convex portion 16, the reaction solution once accumulated in the liquid reservoir concave portion 17 gets over the inner convex portion 15. Is considered difficult. Therefore, since the resist layer 8 effectively exhibits the dam effect (damming effect) of the reaction solution, the reaction solution does not easily get over the resist layer 8.

  Subsequently, the conductor layer 12 is formed by forming the graphite paste layer 13 on the surface of the solid electrolyte layer 11 and further forming the silver paste layer 14 on the surface of the graphite paste layer 13. The conductor layer 12 is formed by using, for example, a screen printing method or a spray coating method. Thereby, one capacitor element 2 is completed.

  The capacitor element laminate 3 is obtained by laminating a plurality of such capacitor elements 2. The conductor layers 12 constituting the cathode part 7 of the capacitor element 2 are joined together by a conductive adhesive 20. As this conductive adhesive, for example, a silver-epoxy adhesive is used.

  The substrate 4 on which such a capacitor element laminate 3 is placed is, for example, an epoxy resin printed substrate. On the upper surface 4 a of the substrate 4, an anode wiring pattern 21 that is electrically connected to the anode portion 6 of the capacitor element laminate 3 and a cathode wiring pattern 22 that is electrically connected to the cathode portion 7 of the capacitor element laminate 3. And are provided. These wiring patterns 21 and 22 are made of copper or the like.

  The cathode portion 7 of the lowermost capacitor element 2 in the capacitor element laminate 3 is bonded to the cathode wiring pattern 22 with a conductive adhesive 20. The anode portion 6 of each capacitor element 2 in the capacitor element laminate 3 is welded to the anode wiring pattern 21 by a welding means such as YAG laser spot welding while being bent and overlapped on the substrate 4 side.

  An anode terminal pattern 23 and a cathode terminal pattern 24 are provided on the lower surface 4 b of the substrate 4. These terminal patterns 23 and 24 are parts mounted on an electronic circuit board or the like (not shown), and are formed of the same metal material as the wiring patterns 21 and 22.

  The substrate 4 is provided with a through hole 25 that electrically connects the anode wiring pattern 21 and the anode terminal pattern 23, and a through hole 26 that electrically connects the cathode wiring pattern 22 and the cathode terminal pattern 24. Yes. These through holes 25 and 26 are formed by, for example, forming a through hole 27 in the substrate 4 by drilling and then plating the inner wall surface of the substrate 4 where the through hole 27 is formed.

  In the present embodiment configured as described above, the resist layer 8 is provided with the liquid reservoir recesses 17 for storing the reaction solution flowing toward the anode part 6 when the cathode part 7 is formed. Even when the thickness D is small, the reaction solution is prevented from flowing over the resist layer 8 and flowing into the anode portion 6 when the solid electrolyte layer 11 is formed. Thereby, in the completed solid electrolytic capacitor 1, it becomes possible to reduce the leakage current defect of the capacitor element 2, and the like.

  For the above reason, it is not necessary to form the resist layer 8 thicker than necessary. Therefore, the bending of the anode portion 6 of each capacitor element 2 (particularly, the uppermost capacitor element 2) in the capacitor element laminate 3 is correspondingly increased. The amount can be reduced. Therefore, it is possible to prevent the aluminum substrate 9 constituting the anode portion 6 from being cracked or damaged, or to prevent the strength of the anode portion 6 from being lowered, so that it is possible to avoid deterioration of the characteristics of the capacitor element 2.

  The present invention is not limited to the above embodiment. For example, as the resist layer having a recess for storing a liquid for storing a reaction solution flowing toward the anode 6 when the cathode 7 is formed, the inner convex portion 15 and the two outer portions particularly as in the above embodiment are used. The shape is not limited to the resist layer 8 composed of the convex portions 16 and can be variously deformed. Modification examples of the resist layer having such a recess for storing liquid are shown in FIGS.

  The resist layer 30 shown in FIG. 6A is formed along the longitudinal direction of the aluminum substrate 9 (the direction from the cathode portion 7 toward the anode portion 6), and is composed of three convex portions 31 having a cross-sectional mountain shape. Yes. The top height positions of the convex portions 31 are the same. And the space between each convex-shaped part 31 forms the recessed part 32 for a liquid reservoir with a cross-sectional substantially V shape.

  The resist layer 35 shown in FIG. 6B is formed along the longitudinal direction of the aluminum substrate 9 and includes two convex portions 36 having a cross-sectional mountain shape. The top height positions of the convex portions 36 are the same. And the space between each convex-shaped part 36 forms the recessed part 37 for a liquid reservoir with a cross-sectional substantially V shape.

  The resist layer 40 shown in FIG. 6C is formed along the longitudinal direction of the aluminum base 9, and is composed of convex portions 41 and 42 having a cross-sectional mountain shape. The top height position of the convex part 42 on the cathode part 7 side is lower than the top height position of the convex part 41 on the anode part 6 side. The space between the convex portions 41 and 42 forms a liquid reservoir concave portion 43 having a substantially V-shaped cross section.

  The resist layer 45 shown in FIG. 7A is formed along the longitudinal direction of the aluminum substrate 9 and has two convex portions 46 having a rectangular cross section. The top height positions of the convex portions 46 are the same. And the space between each convex-shaped part 46 forms the concave part 47 for a liquid reservoir with a rectangular cross section.

  The resist layer 50 shown in FIG. 7B is formed along the longitudinal direction of the aluminum substrate 9 and has convex portions 51 and 52 having a rectangular cross section. The top height position of the convex part 52 on the cathode part 7 side is lower than the top height position of the convex part 51 on the anode part 6 side. A space between the convex portions 51 and 52 forms a liquid pool concave portion 53 having a rectangular cross section.

  The resist layer 55 shown in FIG. 7C is formed along the longitudinal direction of the aluminum base 9 and has two convex portions 56 having a trapezoidal cross section. The top height positions of the convex portions 56 are the same. And the space between each convex-shaped part 56 forms the recessed part 57 for a liquid reservoir with a V-shaped cross section.

  It should be noted that the number of recesses for reservoirs formed in the resist layer may be three or more along the longitudinal direction of the aluminum substrate 9. In addition, the shape of the liquid reservoir recess may be spherical in cross section. Furthermore, the method for forming the recess for liquid pool is not limited to the two-step resin layer printing as in the above embodiment, and the surface of the resin layer may be shaved by etching or the like.

  In the above embodiment, the liquid reservoir recess 17 of the resist layer 8 stores the reaction solution that flows toward the anode portion 6 when the solid electrolyte layer 11 is formed. However, the conductor layer 12 is a subsequent process. Is formed by dipping or the like, the liquid reservoir recess is configured so that the reaction solution used at that time is also stored in the liquid reservoir recess.

  Furthermore, in the said embodiment, although the aluminum base | substrate 9 was used as a valve metal electrode body which forms the anode part 6 of the capacitor | condenser element 2, as a metal material of a valve metal electrode body, in addition to aluminum, aluminum alloy, titanium, tantalum Niobium and zirconium or alloys thereof may be used.

  The solid electrolytic capacitor 1 of the above embodiment is a two-terminal capacitor having one anode portion 6 and one cathode portion 7, but the present invention can also be applied to a multi-terminal capacitor having a plurality of anode portions. It is. Further, the present invention is not limited to the substrate type electrolytic capacitor as in the above embodiment, but can also be applied to a lead frame type solid electrolytic capacitor.

[Example]
The solid electrolytic capacitor according to the above embodiment was produced as follows.

(1) Production of Capacitor Element First, an aluminum foil sheet having a thickness of 100 μm is prepared, which is subjected to a roughening treatment and further has an aluminum oxide film formed thereon. From this aluminum foil sheet, a capacitance of 250 μF / cm ² is obtained. The aluminum foil sheet was punched into a rectangular shape as shown in FIG. 4 to produce an aluminum anode electrode body having an area of 0.1 cm ² . And the roughened structure of the one end side part of the aluminum anode electrode body corresponding to an anode part was destroyed by the press process.

  Subsequently, an epoxy resin was applied to the base end portion of the roughened fracture region of the aluminum anode electrode body to form a resist layer. This resist layer was formed as follows using a screen printing method.

  That is, first, a screen pattern having two linear patterns extending in parallel was prepared in screen printing plate making. Then, using this screen pattern, a resin layer having a width of 0.3 mm and a height of 10 μm was printed and cured at a predetermined temperature. As a result, two linear thermosetting epoxy resin layers as shown in FIG. 5A were formed.

  Furthermore, a screen pattern having one linear pattern was produced in the screen printing plate making. Then, using this screen pattern, a resin layer having a width of 0.3 mm and a height of 10 μm was printed and cured at a predetermined temperature. Thus, one linear thermosetting epoxy resin layer as shown in FIG. 5B was formed between the two previously formed thermosetting epoxy resin layers. As a result, a resist layer having a width of 0.3 mm and a height of 17 μm having two liquid reservoir recesses was formed.

Subsequently, the aluminum anode electrode body was immersed in an aqueous solution of ammonium adipate adjusted to a pH of 6.0 at a concentration of 3% by weight, and the portion where the aluminum oxide film was formed and the roughened structure was maintained was completely Soaked in an aqueous solution. Next, using the anode portion side where the roughened structure in the aluminum anode electrode body was destroyed as an anode, the aluminum anode electrode body in the aqueous solution was oxidized under conditions of a formation current density of 50 to 100 mA / cm ² and a formation voltage of 6 V, An aluminum oxide film was formed on the end face of the cut part of the electrode body.

  Thereafter, the aluminum anode electrode body was pulled out of the aqueous solution, and a solid polymer electrolyte layer made of polypyrrole was formed by chemical oxidative polymerization on the surface (cathode formation region) of the electrode body that had been roughened. . Specifically, a monomer solution composed of pyrrole was impregnated only in a portion of the aluminum foil on which a roughening treatment was performed and an aluminum oxide film was formed, and purified 0.1 mol / l sodium alkylnaphthalene sulfonate and 0. It was generated by setting in an ethanol water mixed solution cell containing 05 mol / l iron (III) sulfate, stirring for 30 minutes to advance chemical oxidative polymerization, and repeating the same operation three times. As a result, a solid polymer electrolyte layer having a maximum thickness of about 10 μm was formed.

  A carbon paste was applied to the surface of the solid polymer electrolyte layer thus obtained, and a silver paste was further applied to the surface of the carbon paste to form a cathode portion. The capacitor element was completed by the above processing. In addition, four such capacitor elements were produced by the same method.

(2) Fabrication of substrate As a substrate, a glass cloth-containing heat-resistant epoxy resin substrate having a size of 7.3 mm in length, 4.3 mm in width, and 0.5 mm in thickness printed with a wiring pattern and a terminal pattern having a thickness of 35 μm ( (Hereinafter referred to as FR4 substrate) was prepared as follows.

  That is, a 0.4 mm thick FR4 substrate coated with a 36 μm thick copper foil on both sides is cut out to a size of 100 mm × 100 mm, and a wiring of a size of 7.3 mm × 4.3 mm is formed on one side (upper surface) thereof. The pattern was patterned by photolithography technology. 96 patterns were formed on the same surface. Further, a terminal pattern was patterned on the lower surface of the FR4 substrate using a photolithography technique while aligning with the wiring pattern.

  Subsequently, a plurality of through holes (0.3 mmφ) for connecting the wiring pattern formed on the upper surface of the FR4 substrate and the terminal pattern formed on the lower surface of the FR4 substrate were formed. Subsequently, 3 μm nickel plating was applied to the inner wall of the FR4 substrate part forming the through hole by electroless plating, and 0.8 μm gold plating was further formed thereon to form a through hole.

(3) Mounting Capacitor Elements on Substrate The anode parts of the four capacitor elements prepared above are aligned so as to overlap each other, and these capacitor elements are stacked, and the cathode parts (paste layer) of each capacitor element They were bonded together with a conductive adhesive to produce one capacitor element laminate.

  Such a capacitor element laminated body was mounted on the FR4 substrate, and a cathode part (paste layer) exposed on the lowermost surface of the laminated body was adhered to the cathode wiring pattern using a silver-epoxy conductive adhesive. Moreover, each anode part of the capacitor | condenser element laminated body was welded and integrated with the anode wiring pattern using the YAG laser welding machine made from NEC.

  Thereafter, the stacked body placed and fixed in a predetermined region on the FR4 substrate was molded with an epoxy resin by a casting mold using a vacuum printing method.

  Dicing cutting was performed at intervals of 7.3 mm × 4.3 mm on the basis of a predetermined marking position with the mold surface of the FR4 substrate having a size of 100 mm × 100 mm molded as described above facing upward. After washing, a discrete type two-terminal solid electrolytic capacitor sample # 1 having a capacitor element of 7.3 mm × 4.3 mm was obtained. Thereafter, an aging process was performed by applying a constant voltage to the solid electrolytic capacitor by a known method, and the leakage current was sufficiently reduced to complete the solid electrolytic capacitor sample # 1.

(4) Evaluation About the electrical characteristics of about 100 samples # 1 obtained in this way, the leakage current value was measured. A method for measuring leakage current is already known, and a DC stabilized power source and an ammeter that can apply a rated voltage (4 V) to a prototype solid electrolytic capacitor were prepared, and the solid electrolytic capacitor was connected according to the polarity of the power source. At that time, a resistance of 1 kΩ was connected in series with an ammeter as a protection circuit. And 5 minutes after turning on the power, the number of samples that reached a current value below a certain standard value was counted. As a result, 89 samples satisfy the leakage current standard value (40 μA or less).

[Comparative example]
A solid electrolytic capacitor as a comparative example was produced as follows.

  That is, first, the same aluminum anode electrode body was produced as in the above example. Subsequently, an epoxy resin was applied to the base end portion of the roughened fracture region of the aluminum anode electrode body to form a resist layer. Specifically, a screen pattern having one linear pattern was prepared in screen printing plate making. Then, using this screen pattern, a resin layer having a width of 0.7 mm and a height of 22 μm was printed and cured at a predetermined temperature. Thereby, the linear thermosetting epoxy resin layer without the recessed part for liquid pools was formed.

  Thereafter, in the same manner as in the above example, about 100 two-terminal solid electrolytic capacitor samples # 2 were produced and evaluated in the same manner. As a result, 60 samples satisfied the leakage current standard value (40 μA or less).

  Here, in the solid electrolytic capacitor sample # 1 manufactured in [Example] described above and the conventional solid electrolytic capacitor sample # 2 manufactured in [Comparative Example], the electrode manufacturing method, the insulating oxide film, The formation method, the type of solid polymer compound used, and the size of the finished part are the same. The difference is the shape of the resist layer of the capacitor element, that is, the presence or absence of a liquid pool recess in the resist layer. Therefore, it is considered that the shape of the resist layer affects the characteristics of the solid electrolytic capacitor. From the above results, the effect of the solid electrolytic capacitor according to the present invention could be confirmed.

It is sectional drawing which shows one Embodiment of the solid electrolytic capacitor concerning this invention. It is sectional drawing which shows the specific structure of the capacitor | condenser element shown in FIG. FIG. 3 is a partially enlarged cross-sectional view of the capacitor element shown in FIG. 2. FIG. 3 is a plan view of the capacitor element shown in FIG. 2. It is sectional drawing which shows the process of forming the resist layer shown in FIG. It is a figure which shows the modification of the resist layer shown in FIG. It is a figure which shows the other modification of the resist layer shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Solid electrolytic capacitor, 2 ... Capacitor element, 6 ... Anode part, 7 ... Cathode part, 8 ... Resist layer, 9 ... Aluminum base | substrate (valve metal electrode body), 11 ... Solid electrolyte layer, 12 ... Conductor layer, 15 ... inner convex part (first convex part), 16 ... outer convex part (second convex part), 17 ... concave part for liquid reservoir, 30 ... resist layer, 31 ... convex part, 32 ... for liquid reservoir Recess, 35 ... resist layer, 36 ... convex portion, 37 ... recess for liquid pool, 40 ... resist layer, 41 ... convex portion (first convex portion), 42 ... convex portion (second convex portion) , 43 ... concave portion for liquid reservoir, 45 ... resist layer, 46 ... convex portion, 47 ... concave portion for liquid reservoir, 50 ... resist layer, 51 ... convex portion (first convex portion), 52 ... convex portion ( (Second convex portion), 53 ... concave portion for liquid reservoir, 55 ... resist layer, 56 ... convex portion, 57 ... concave portion for liquid reservoir.

Claims (3)

A solid electrolytic capacitor having a capacitor element,
The capacitor element is
An anode formed in a partial region of the valve metal substrate;
A cathode part formed by laminating a solid electrolyte layer and a conductor layer on the surface of the valve metal substrate excluding the anode part; and
A resist layer for electrically separating the anode part and the cathode part;
A solid electrolytic capacitor, wherein the resist layer is provided with a recess for storing a liquid for storing a reaction solution flowing toward the anode when the cathode is formed. The resist layer includes a first convex portion and a second convex portion that is formed on the cathode portion side with respect to the first convex portion and has a top height position lower than that of the first convex portion. Have
2. The solid electrolytic capacitor according to claim 1, wherein the liquid reservoir recess is formed in a space between the first convex portion and the second convex portion. The resist layer is formed along a parallel direction of the anode portion and the cathode portion, and has a plurality of convex portions having a cross-sectional mountain shape,
The solid electrolytic capacitor according to claim 1, wherein the liquid reservoir concave portion is formed in a space between the convex portions.

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