Method for producing solid electrolytic capacitor, and solid electrolytic capacitor

Abstract

This method for producing a solid electrolytic capacitor comprises: a first step in which an insulator layer 20 is formed between an element cathode section 14 and an element anode section 13 of an anode body 10; and a second step in which a solid electrolyte layer 30 is formed by printing or transfer from the element cathode section 14 side to a range not surpassing the insulator layer 20.

Description

Method for manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor

[0001] The present invention relates to a method for manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor.

[0002] Patent Document 1 describes a solid electrolytic capacitor element in which a dielectric layer, a solid electrolyte layer, a carbon paste layer, and a conductive paste layer are sequentially laminated on the surface of a valve metal plate, the solid electrolytic capacitor element having an end of the carbon paste layer on the solid electrolyte layer, the end of the carbon paste layer being covered with an insulating resin layer, and the maximum thickness of the capacitor element in the insulating resin layer portion being equal to or less than the maximum thickness of the capacitor element in the conductive paste layer portion.

[0003] Patent Document 2 describes a solid electrolytic capacitor element having a valve metal substrate having an anode terminal region and a cathode formation region, a dielectric layer formed on the cathode formation region, a solid electrolyte layer formed on the dielectric layer, and a current collecting layer formed on the solid electrolyte layer, wherein a masking region made of a masking member is formed on the anode terminal region to separate the anode terminal region from the cathode formation region and to insulate the valve metal substrate from a counter electrode, a hydrophilic region made of a hydrophilic member is formed on a surface of the masking member, and the masking member is formed at least on an end of the masking region on the cathode formation region side, and the masking member is a member having a lower hydrophilicity than the hydrophilic member.

[0004] Patent Document 3 describes a solid electrolytic capacitor element including: an anode made of a valve metal substrate and having a tip end surface and a base end surface; a dielectric layer provided on at least one main surface of the anode excluding at least the base end surface; a mask layer made of an insulating material provided on the dielectric layer along the base end surface; and a cathode provided on the dielectric layer on the tip end surface side of the mask layer, wherein the cathode has a solid electrolyte layer provided on the dielectric layer and a conductive layer provided on the solid electrolyte layer, and the solid electrolyte layer has convex portions along the mask layer, and the maximum thickness of the solid electrolyte layer at the convex portions is greater than the thickness of the solid electrolyte layer in the remaining portion excluding the convex portions.

[0005] JP 2011-155236 A JP 2020-205446 A International Publication No. 2023 / 026708

[0006] In a laminated solid electrolytic capacitor in which multiple solid electrolytic capacitor elements are electrically arranged in parallel and covered with a sealing resin except for the external electrode terminals, an exposed portion of the oxide film may occur on the outer surface of the cathode part of the solid electrolytic capacitor element between the insulator layer and the solid electrolyte layer. In this case, the oxide film may be damaged by the molding pressure of the sealing resin or thermal stress during reflow, and the exposed aluminum substrate may come into contact with the solid electrolyte layer that has penetrated the porous layer, which may increase leakage current or cause a short circuit.

[0007] In addition to the above-mentioned stress, it has also been pointed out that the conductive layer, such as the carbon layer or silver layer, may extend beyond the edge of the solid electrolyte layer and come into contact with the exposed part of the oxide film, resulting in an increase in leakage current or the occurrence of a short circuit.

[0008] The solid electrolytic capacitor element described in Patent Document 1 is effective in preventing leakage current and short circuits, but has a major disadvantage in that the conductive paste layer does not overlap with the insulating resin layer, which reduces the area of ​​the conductive paste layer and increases the equivalent series resistance (ESR).

[0009] The solid electrolytic capacitor element described in Patent Document 2 is effective in preventing leakage current and short circuits, but also proposes the use of silane coupling agents, chelating agents, etc. as a method for partially imparting hydrophilicity to the element. However, it is technically difficult to selectively form these materials on the masking member, and further, the adhesion of these materials to the dielectric layer and solid electrolyte layer in the cathode formation region leads to a decrease in capacitance and an increase in equivalent series resistance.

[0010] The solid electrolytic capacitor element described in Patent Document 3 is effective in preventing leakage current and short circuits, but in order to selectively form a thick solid electrolyte layer near the mask layer, it is necessary to form a thick outer periphery of the solution for forming the solid electrolyte layer, such as a solution containing a chemical polymerization monomer, an oxidizing agent, a dopant, etc., by utilizing the coffee ring effect. This requires adjustment of the viscosity, surface tension, contact angle, etc., which is technically difficult and reduces the degree of freedom in designing the solid electrolyte layer.

[0011] The present invention has been made to solve the above problems, and aims to provide a method for manufacturing a solid electrolytic capacitor that can suppress leakage current and short circuits in a simple manner and that can produce a solid electrolytic capacitor with low equivalent series resistance, and a solid electrolytic capacitor that suppresses leakage current and short circuits and has low equivalent series resistance.

[0012] The method for manufacturing a solid electrolytic capacitor of the present invention includes a first step of forming an insulator layer between an element anode portion and an element cathode portion of an anode body, and a second step of forming a solid electrolyte layer by printing or transfer from the element cathode portion side to an area not exceeding the insulator layer.

[0013] The solid electrolytic capacitor of the present invention includes an anode body, an insulator layer provided between an element anode portion and an element cathode portion of the anode body, and a solid electrolyte layer provided from the element cathode portion side to an area exceeding one-half but not exceeding three-quarters of the width of the insulator layer.

[0014] According to the present invention, it is possible to provide a method for manufacturing a solid electrolytic capacitor that can suppress leakage current and short circuits in a simple manner and that can produce a solid electrolytic capacitor with low equivalent series resistance, and a solid electrolytic capacitor that suppresses leakage current and short circuits and has low equivalent series resistance.

[0015] FIG. 1 is a cross-sectional view schematically showing an example of an anode body used in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 2 is a cross-sectional view schematically showing an example of a step of forming an insulator layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 3A is a cross-sectional view schematically showing an example of a step of forming a solid electrolyte layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 3B is an enlarged cross-sectional view of a portion including the insulator layer shown in FIG. 3A. FIG. 4 is a schematic diagram of an example of a roller transfer device used to transfer the solid electrolyte material. FIG. 5 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 6 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor fabricated by the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 7 is a cross-sectional view schematically showing an example of a step of forming an insulator layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 2. FIG. 8 is a cross-sectional view schematically showing an example of a step of forming a first solid electrolyte layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 2. FIG. 9 is a cross-sectional view schematically showing an example of a step of forming a second solid electrolyte layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 2. FIG. 10 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 2. FIG. 11 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor manufactured by the method for manufacturing a solid electrolytic capacitor according to embodiment 2. FIG. 12 is a cross-sectional view schematically showing an example of a step of forming an insulator layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. FIG. 13 is a cross-sectional view schematically showing an example of a step of forming a solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. FIG. 14 is a cross-sectional view schematically showing an example of a step of removing a solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. FIG. 15 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. FIG. 16 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor manufactured by the method for manufacturing a solid electrolytic capacitor according to embodiment 3.Fig. 17 is a cross-sectional view schematically showing an example of a step of forming a solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 4. Fig. 18 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 4. Fig. 19 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor fabricated by the method for manufacturing a solid electrolytic capacitor according to embodiment 4.

[0016] The following describes a method for manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor. However, the present invention is not limited to the following configurations and can be appropriately modified and applied within the scope of the present invention. Note that a combination of two or more of the individual desirable configurations described below also constitutes the present invention.

[0017] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0018] In this specification, terms indicating the relationship between elements (e.g., "parallel," "perpendicular," "orthogonal," etc.) and terms indicating the shapes of elements not only mean the literal strict form, but also mean a range that is substantially equivalent, for example, a range that includes a difference of about a few percent.

[0019] (Embodiment 1) A method for manufacturing a solid electrolytic capacitor according to embodiment 1 of the present invention includes a first step of forming an insulator layer between an element anode portion and an element cathode portion of an anode body, and a second step of forming a solid electrolyte layer by printing or transferring from the element cathode portion side to an area not exceeding the insulator layer.

[0020] According to the above manufacturing method, the solid electrolyte layer is formed continuously onto the insulator layer, which prevents stresses such as molding pressure of the sealing resin and thermal stress during reflow, and prevents conductive layers such as the carbon layer and silver layer from coming into contact with the oxide film, thereby suppressing leakage current and short circuits.

[0021] Furthermore, since there is no need to provide an insulating resin layer as in Patent Document 1 and the conductive layer can be formed up to the insulator layer, the area of ​​the conductive layer can be made larger and the equivalent series resistance (ESR) can be reduced.

[0022] Furthermore, according to the above manufacturing method, since the solid electrolyte layer is formed by printing or transfer, there is no need to partially provide a hydrophilic region on the insulator layer as in Patent Document 2, and there is no need to provide a convex portion of the solid electrolyte layer near the insulator layer as in Patent Document 3. Therefore, a simple manufacturing method can be realized.

[0023] One method for forming a solid electrolyte layer on an insulator layer without providing a hydrophilic region is to use a specific application method, specifically, to use printing or transfer when forming the solid electrolyte layer. When forming a solid electrolyte layer by dipping, the solid electrolyte layer is biased downward due to the weight of the polymer dispersion. In contrast, if a method such as printing or transfer in a planar direction is used, the bias due to the weight of the dispersion is alleviated. In addition, since materials with high leveling properties can be used for printing and transfer, it is possible to form a solid electrolyte layer on an insulator layer without providing a hydrophilic region.

[0024] In the second step, the solid electrolyte layer is preferably formed from the cathode side of the element to a range of ¾ or less of the width of the insulator layer. This avoids the risk of molten metal spatters, which are generated when welding the anode part of the element to the anode lead frame, coming into contact with the solid electrolyte layer. It also avoids the risk of the anode lead frame between adjacent solid electrolytic capacitor elements coming into contact with the solid electrolyte layer on the insulator layer due to misalignment during stacking of the solid electrolytic capacitor elements.

[0025] Although there is no particular lower limit to the width of the solid electrolyte layer formed on the insulator layer (the width of the solid electrolyte portion present on the insulator layer), it is desirable that at least about ⅕ of the width of the insulator layer from the cathode side of the element be covered with the solid electrolyte layer, because the insulator layer is generally formed in a tapered shape, and the thickness of the portion in contact with the cathode side of the element is thin.

[0026] More preferably, in the second step, the solid electrolyte layer is formed to an extent of at least one-third of the width of the insulator layer from the cathode portion side of the element, and even more preferably, in the second step, the solid electrolyte layer is formed to an extent of more than one-half of the width of the insulator layer from the cathode portion side of the element.

[0027] The insulator layer does not need to be water-repellent, and depending on the method for forming the solid electrolyte layer, the insulator layer may be hydrophilic to make it easier to form the solid electrolyte layer on the insulator layer.

[0028] In order to facilitate the formation of the solid electrolyte layer on the insulator layer, the chemical polymerization solution for forming the solid electrolyte layer, the dispersion liquid containing conductive polymer particles, or the like may contain an additive for adjusting the rheology, interfacial tension, or the like.

[0029] The method for manufacturing a solid electrolytic capacitor according to this embodiment will be described in more detail below with reference to the drawings.

[0030] FIG. 1 is a cross-sectional view schematically showing an example of an anode body used in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 2 is a cross-sectional view schematically showing an example of a step of forming an insulator layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 3A is a cross-sectional view schematically showing an example of a step of forming a solid electrolyte layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1, and FIG. 3B is an enlarged cross-sectional view of a portion including the insulator layer shown in FIG. 3A. FIG. 4 is a schematic diagram of an example of a roller transfer device used to transfer the solid electrolyte material. FIG. 5 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing the solid electrolytic capacitor according to Embodiment 1. FIG. 6 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor produced by the method for manufacturing the solid electrolytic capacitor according to Embodiment 1.

[0031] First, as shown in Fig. 1, a flat anode body 10 is prepared by etching to make it multifaceted (porous) and then anodizing (chemical conversion treatment) to form an oxide film (not shown) on its surface. The anode body 10 functions as the anode of the solid electrolytic capacitor element.

[0032] A valve metal substrate having a porous portion on the surface is used as the anode body 10. The anode body 10 is a thin film (foil) having a rectangular shape in plan view and including a metal substrate portion 11 and a porous portion 12 on the metal substrate portion 11.

[0033] In this specification, the term "plan view" means a view from the normal direction of the main surface of the anode foil.

[0034] The valve metal substrate is made of a valve metal such as an elemental metal such as aluminum, tantalum, niobium, titanium, or zirconium, or an alloy containing these metals.

[0035] The valve metal substrate may be formed of a core and a porous portion provided on at least one of the main surfaces of the core, and may be formed from a metal foil having an etched surface, a metal foil having a porous sintered powder body formed on the surface, or the like.

[0036] One longitudinal end of the anode body 10 is an anode portion 13, and the other longitudinal end is a cathode portion 14. The anode portion 13 and the cathode portion 14 each have a rectangular shape in plan view.

[0037] An oxide film is provided as a dielectric layer on the surface of the porous portion 12 of the anode body 10 and on the end of the element cathode portion 14 opposite to the element anode portion 13. The oxide film is made of, for example, an oxide of aluminum. The oxide film is formed along the surface of the porous portion 12, thereby forming pores (recesses).

[0038] 2 , an insulator layer 20 is formed to cover the outer periphery of the anode body 10 between the anode portion 13 and the cathode portion 14. That is, the insulator layer 20 is formed in a ring shape around the anode body 10 along the boundary between the anode portion 13 and the cathode portion 14.

[0039] The insulator layer 20 is formed by applying a mask material such as a composition containing an insulating resin by screen printing, roller transfer, dispenser, inkjet printing, etc. Examples of insulating resins include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), a composition consisting of soluble polyimide siloxane and epoxy resin, polyimide resin, polyamide-imide resin, and derivatives or precursors thereof.

[0040] After this, the insulating layer 20 may or may not be coated with a hydrophilic material.

[0041] Next, as shown in Fig. 3A, the solid electrolyte layer 30 is formed by printing or transfer on the cathode portion 14 and the insulator layer 20 on the cathode portion 14 side, from the cathode portion 14 side to an area of ​​¾ or less of the width of the insulator layer 20 (the area indicated by W1 in Fig. 3B). That is, the end of the solid electrolyte layer 30 on the anode portion 13 side is present in the area indicated by W1 in Fig. 3B.

[0042] In this case, it is preferable to form the solid electrolyte layer 30 from the cathode 14 side of the element to an area of ​​at least one-third but not more than three-quarters of the width of the insulator layer 20 (the area indicated by W2 in FIG. 3B ), and it is more preferable to form the solid electrolyte layer 30 from the cathode 14 side of the element to an area of ​​more than one-half but not more than three-quarters of the width of the insulator layer 20 (the area indicated by W3 in FIG. 3B ). That is, it is preferable that the end of the solid electrolyte layer 30 on the anode 13 side of the element is located within the area indicated by W2 in FIG. 3B , and it is more preferable that it is located within the area indicated by W3.

[0043] As shown in FIG. 3B , insulator layer 20 normally includes a portion that fills porous portion 12 (the pores thereof) of anode body 10 and a portion that is exposed on the outer surface of porous portion 12. The width of insulator layer 20 means the dimension in the longitudinal direction of the portion that is exposed on the outer surface of porous portion 12 (the range indicated by W in FIG. 3B ).

[0044] Furthermore, in this specification, the preferred ranges for forming the solid electrolyte layer or the conductive layer are all described as the preferred ranges for forming the solid electrolyte layer or the conductive layer in a dried state. For example, when the solid electrolyte layer or the conductive layer is formed from a liquid material (a treatment liquid or a conductive paste containing a solid electrolyte), the preferred ranges are described as the ranges that should be filled after the liquid material is dried.

[0045] When the solid electrolyte layer 30 is formed by transfer, it may be formed by roller transfer, for example, as shown in FIG.

[0046] The roller transfer device 200 shown in FIG. 4 includes a vertical conveying roller transfer unit 220A, and an assembly 10A having a strip or fishbone structure and including a plurality of anode bodies is conveyed through the roller transfer unit 220A at a predetermined conveying speed.

[0047] The roller transfer unit 220A transfers the treatment liquid containing the solid electrolyte onto the element cathode portions of the assembly 10A while transporting the supplied assembly 10A.

[0048] The roller transfer unit 220A has a plurality of transport rollers 221 that transport the assembly 10A on a transport path formed by the assembly 10A, a pair of rollers (transfer rollers) 222 between which the element cathode parts of the assembly 10A are transported, and a dispenser 223 and a squeegee 224 provided on each roller 222.

[0049] The pair of rollers 222 are provided on both sides of the assembly 10A transported by the transport roller 221. Each roller 222 has a circumferential surface made of metal or rubber, and grooves are formed on the circumferential surface to supply the treatment liquid containing a solid electrolyte. The depth of the grooves can be appropriately set taking into account the desired coating thickness of the treatment liquid containing a solid electrolyte. The circumferential surface of each roller 222 may not be grooved, and may be smooth. The circumferential surface may also be roughened by sandblasting or other methods. The circumferential surfaces of the pair of rollers 222 are spaced apart from each other by a predetermined distance from the opposite main surfaces of the cathode element of the assembly 10A. The treatment liquid containing a solid electrolyte contacts the cathode element, and the treatment liquid containing a solid electrolyte on the circumferential surfaces of the pair of rollers 222 is transferred onto the opposite main surfaces of the cathode element. The positions of the pair of rollers 222 and the assembly 10A are set so that the treatment liquid containing a solid electrolyte also contacts a portion of the insulator layer, and the treatment liquid containing a solid electrolyte is also transferred onto the insulator layer.

[0050] Each dispenser 223 supplies an appropriate amount of treatment liquid containing a solid electrolyte to the corresponding roller 222, and the treatment liquid containing a solid electrolyte does not drip from the circumferential surface of the roller 222. This makes it possible to minimize the consumption of the treatment liquid containing a solid electrolyte. The supply of the treatment liquid containing a solid electrolyte to the roller 222 may be continuous or intermittent.

[0051] Each squeegee 224 is positioned a predetermined distance away from the circumferential surface of the corresponding roller 222, and adjusts the amount of treatment liquid containing a solid electrolyte adhering to the circumferential surface of the corresponding roller 222 by scraping it off.

[0052] The treatment liquid containing the solid electrolyte is then dried to form the solid electrolyte layer 30. This drying may be natural drying, heat drying, or both.

[0053] When forming solid electrolyte layer 30 by transfer, a horizontally conveying roller transfer unit may be used instead of vertically conveying roller transfer unit 220A. That is, the treatment liquid containing a solid electrolyte may be transferred while horizontally conveying assembly 10A including a plurality of anode elements. In this case, solid electrolyte layer 30 can be formed at a targeted position on insulator layer 20 with even greater precision.

[0054] When the solid electrolyte layer 30 is formed by printing, for example, screen printing or inkjet printing can be used.

[0055] Solid electrolyte layer 30 is provided on the oxide film in element cathode portion 14. Solid electrolyte layer 30 is preferably provided so as to fill a plurality of pores (recesses) in porous portion 12 of anode body 10. However, it is sufficient that part of the outer surface of the oxide film is covered with solid electrolyte layer 30, and there may be pores (recesses) in porous portion 12 of anode body 10 that are not filled with solid electrolyte layer 30.

[0056] The treatment liquid containing a solid electrolyte may be, for example, a dispersion of a conductive polymer such as polypyrroles, polythiophenes, or polyanilines. Among these, polythiophenes are preferred, with poly(3,4-ethylenedioxythiophene), also known as PEDOT, being particularly preferred. The conductive polymer may also contain a dopant such as polystyrene sulfonic acid (PSS). A conductive polymer film can be formed by applying a conductive polymer dispersion to the outer surface of the oxide film and drying it. Alternatively, a liquid containing a polymerizable monomer, such as 3,4-ethylenedioxythiophene, may also be used as the treatment liquid containing a solid electrolyte precursor. The polymerizable monomer may contain a dopant, such as polystyrene sulfonic acid. The treatment liquid containing a solid electrolyte precursor may also contain an oxidizing agent. This treatment liquid may be applied to the outer surface of the oxide film, and a conductive polymer film can be formed by oxidative polymerization (chemical polymerization). This conductive polymer film becomes the solid electrolyte layer 30.

[0057] 5 , a carbon layer 41 and a conductive paste layer 42 (e.g., a silver layer) are sequentially laminated on the solid electrolyte layer 30 as the conductive layer 40 to form a solid electrolytic capacitor element 51. The solid electrolyte layer 30 and the conductive layer 40 function as the cathode of the solid electrolytic capacitor element 51.

[0058] The carbon layer 41 is formed, for example, by applying a carbon paste containing carbon particles and resin to the surface of the solid electrolyte layer 30 and drying it.

[0059] The carbon paste can be applied by, for example, a dipping method, sponge transfer, screen printing, spray application, a dispenser, inkjet printing, or the like.

[0060] The conductive paste layer 42 is formed by, for example, applying a conductive paste containing metal particles such as gold, silver, copper, or platinum and a resin to the surface of the carbon layer 41 and drying the paste. The conductive paste layer 42 is preferably a silver layer.

[0061] The conductive paste can be applied by, for example, a dipping method, sponge transfer, screen printing, spray application, a dispenser, inkjet printing, or the like.

[0062] As the conductive layer 40, only one of the carbon layer 41 and the conductive paste layer 42 may be formed.

[0063] Then, as shown in FIG. 6 , a plurality of similarly prepared solid electrolytic capacitor elements 51 are stacked, and an anode lead frame 61 and an element anode portion 13 are welded together, and a cathode lead frame 62 and a conductive layer 40 are connected with a conductive adhesive 70 such as adhesive silver to form a stacked solid electrolytic capacitor element. Thereafter, the anode lead frame 61 and the cathode lead frame 62 are covered with a sealing resin 80 except for the portions necessary for mounting on the substrate, thereby producing a solid electrolytic capacitor 101.

[0064] 6 , solid electrolytic capacitor 101 according to embodiment 1 of the present invention includes anode body 10, insulator layer 20 provided between element anode portion 13 and element cathode portion 14 of anode body 10, and solid electrolyte layer 30 provided from the element cathode portion 14 side to an area exceeding one-half to not more than three-quarters of the width of insulator layer 20. Therefore, as described above, leakage current and short circuits can be suppressed, and equivalent series resistance can be reduced.

[0065] (Embodiment 2) A method for manufacturing a solid electrolytic capacitor according to Embodiment 2 of the present invention differs from Embodiment 1 in the following respects: the second step includes the steps of forming a first solid electrolyte layer only on the cathode portion of the element so that an oxide film is exposed between the first solid electrolyte layer and the insulator layer, and forming a second solid electrolyte layer by printing or transferring from the cathode portion side of the element to an area that is ¾ or less of the width of the insulator layer, and the second solid electrolyte layer is formed continuously from a part of the first solid electrolyte layer to a part of the insulator layer so as to cover the exposed part of the oxide film.

[0066] According to the above manufacturing method, the second solid electrolyte layer can be formed thickly on the exposed portion of the oxide film, thereby further suppressing leakage current and short circuits. Although the first solid electrolyte layer and the second solid electrolyte layer are required to have different functions, using different materials for them does not impair the design freedom for each.

[0067] The method for manufacturing a solid electrolytic capacitor according to this embodiment will be described in more detail below with reference to the drawings.

[0068] Fig. 7 is a cross-sectional view schematically showing an example of a step of forming an insulator layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 2. Fig. 8 is a cross-sectional view schematically showing an example of a step of forming a first solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 2. Fig. 9 is a cross-sectional view schematically showing an example of a step of forming a second solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 2. Fig. 10 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 2. Fig. 11 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor produced by the method for manufacturing a solid electrolytic capacitor according to embodiment 2.

[0069] First, as shown in FIG. 7, similarly to the first embodiment, an anode body 10 having an oxide film (not shown) formed thereon is produced, and an insulator layer 20 is formed on the anode body 10 .

[0070] 8, a conductive polymer is formed only on the cathode portion 14 of the element by a method such as chemical polymerization, and this conductive polymer serves as the first solid electrolyte layer 31. An exposed portion 15 of the oxide film exists between the first solid electrolyte layer 31 and the insulator layer 20.

[0071] The method for forming the first solid electrolyte layer 31 is not particularly limited, and for example, dipping may be used.

[0072] Next, as shown in FIG. 9 , a dispersion of a conductive polymer whose rheology, interfacial tension, etc. have been adjusted is printed onto first solid electrolyte layer 31 on the insulator layer 20 side, exposed portion 15 of the oxide film, and an area extending from the element cathode portion 14 side of insulator layer 20 to not more than ¾ of the width of insulator layer 20, and this conductive polymer forms second solid electrolyte layer 32.

[0073] In this case, similarly to the first embodiment, it is preferable to form the second solid electrolyte layer 32 from the cathode portion 14 side of the element to an extent of not less than one-third and not more than three-quarters of the width of the insulator layer 20 (see the range indicated by W2 in FIG. 3B ), and it is more preferable to form the second solid electrolyte layer 32 from the cathode portion 14 side of the element to an extent of more than one-half and not more than three-quarters of the width of the insulator layer 20 (see the range indicated by W3 in FIG. 3B ).

[0074] The printing method for forming the second solid electrolyte layer 32 may be, for example, screen printing or inkjet printing.

[0075] In this embodiment, the solid electrolyte layer 30 is formed from the first solid electrolyte layer 31 and the second solid electrolyte layer 32 .

[0076] 10 , similarly to the first embodiment, a carbon layer 41 and a conductive paste layer 42 (e.g., a silver layer) are sequentially laminated on the solid electrolyte layer 30 as the conductive layer 40 to form a solid electrolytic capacitor element 52. In this case, only one of the carbon layer 41 and the conductive paste layer 42 may be formed as the conductive layer 40.

[0077] Thereafter, the same procedures as in the first embodiment are carried out to fabricate a solid electrolytic capacitor 102 as shown in FIG.

[0078] 11 , in the solid electrolytic capacitor 102 according to the second embodiment of the present invention, the solid electrolyte layer 30 includes a first solid electrolyte layer 31 and a second solid electrolyte layer 32, the first solid electrolyte layer 31 being provided only on the cathode portion 14 of the element, away from the insulator layer 20, and the second solid electrolyte layer 32 being provided from the cathode portion 14 side to an area exceeding one-half to three-quarters of the width of the insulator layer 20, and being provided continuously from a part of the first solid electrolyte layer 31 to a part of the insulator layer 20 so as to cover an oxide film (not shown) between the first solid electrolyte layer 31 and the insulator layer 20. Therefore, as described above, leakage current and short circuits can be further suppressed.

[0079] (Embodiment 3) A method for manufacturing a solid electrolytic capacitor according to Embodiment 3 of the present invention differs from Embodiment 1 in the following respects: the second step includes the steps of forming a solid electrolyte layer by printing or transferring from the cathode side of the element to an area exceeding three-quarters of the width of the insulator layer, and removing the solid electrolyte layer from the cathode side of the element to an area exceeding three-quarters of the width of the insulator layer and roughening the surface of the insulator layer.

[0080] According to the above manufacturing method, a simple manufacturing method can be realized for forming a solid electrolyte layer in a desired region on an insulating layer.

[0081] The method for manufacturing a solid electrolytic capacitor according to this embodiment will be described in more detail below with reference to the drawings.

[0082] Fig. 12 is a cross-sectional view schematically showing an example of a step of forming an insulator layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. Fig. 13 is a cross-sectional view schematically showing an example of a step of forming a solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. Fig. 14 is a cross-sectional view schematically showing an example of a step of removing a solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. Fig. 15 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 3. Fig. 16 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor produced by the method for manufacturing a solid electrolytic capacitor according to embodiment 3.

[0083] First, as shown in FIG. 12, similarly to the first embodiment, an anode body 10 having an oxide film (not shown) formed thereon is produced, and an insulator layer 20 is formed on the anode body 10 .

[0084] 13, the solid electrolyte layer 30 is formed by printing or transfer, as in the first embodiment. However, the solid electrolyte layer 30 is formed so as to extend beyond three-quarters of the width of the insulator layer 20 from the cathode portion 14 side of the element. However, the end of the solid electrolyte layer 30 on the anode portion 13 side of the element does not extend beyond the insulator layer 20.

[0085] 14 , a portion of the solid electrolyte layer 30 on the insulator layer 20 is removed from the anode portion 13 side of the element by a method such as a laser, leaving the solid electrolyte layer 30 in an area extending from the cathode portion 14 side of the element to a width of ¾ or less of the insulator layer 20. As a result, at least in the region where the solid electrolyte layer 30 has been removed, a portion of the insulator layer 20 is also removed, and the surface of that portion is roughened.

[0086] In this case, similarly to the first embodiment, it is preferable to leave the solid electrolyte layer 30 so that the end of the solid electrolyte layer 30 on the anode portion 13 side of the element is in a range of not less than 1 / 3 and not more than 3 / 4 of the width of the insulator layer 20 from the cathode portion 14 side of the element (see the range indicated by W2 in FIG. 3B ), and it is more preferable to leave the solid electrolyte layer 30 so that the end of the solid electrolyte layer 30 on the anode portion 13 side of the element is in a range of not more than 1 / 2 and not more than 3 / 4 of the width of the insulator layer 20 from the cathode portion 14 side of the element (see the range indicated by W3 in FIG. 3B ).

[0087] 15 , similarly to the first embodiment, a carbon layer 41 and a conductive paste layer 42 (e.g., a silver layer) are sequentially laminated as the conductive layer 40 on the solid electrolyte layer 30 to form a solid electrolytic capacitor element 53. In this case, only one of the carbon layer 41 and the conductive paste layer 42 may be formed as the conductive layer 40.

[0088] Thereafter, the same procedures as in the first embodiment are carried out to fabricate a solid electrolytic capacitor 103 as shown in FIG.

[0089] 16 , in solid electrolytic capacitor 103 according to embodiment 3 of the present invention, the surface of insulator layer 20 is roughened in an area extending from the element cathode portion 14 side to more than ¾ of the width of insulator layer 20. Like solid electrolytic capacitor 101 according to embodiment 1, solid electrolytic capacitor 103 according to embodiment 3 can suppress leakage current and short circuits and can also reduce equivalent series resistance.

[0090] A method for manufacturing a solid electrolytic capacitor according to a fourth embodiment of the present invention differs from that of the first embodiment in the following respects: a conductive layer is formed on a solid electrolyte layer from the cathode side of the element to an area of ​​¾ or less of the width of the insulator layer.

[0091] According to the above manufacturing method, the area of ​​the conductive layer can be increased, and the equivalent series resistance can be further reduced.

[0092] The method for manufacturing a solid electrolytic capacitor according to this embodiment will be described in more detail below with reference to the drawings.

[0093] Fig. 17 is a cross-sectional view schematically showing an example of a step of forming a solid electrolyte layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 4. Fig. 18 is a cross-sectional view schematically showing an example of a step of forming a conductive layer in the method for manufacturing a solid electrolytic capacitor according to embodiment 4. Fig. 19 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor fabricated by the method for manufacturing a solid electrolytic capacitor according to embodiment 4.

[0094] First, as shown in FIG. 17 , similarly to the first embodiment, an anode body 10 having an oxide film (not shown) formed thereon is produced, an insulator layer 20 is formed on the anode body 10, and a solid electrolyte layer 30 is formed by printing or transfer.

[0095] 18, a carbon layer 41 and a conductive paste layer 42 (e.g., a silver layer) are sequentially laminated on the solid electrolyte layer 30 as the conductive layer 40 to form a solid electrolytic capacitor element 54. At this time, the conductive layer 40 is formed from the element cathode portion 14 side to an area of ​​¾ or less of the width of the insulator layer 20. In other words, the end of the conductive layer 40 on the element anode portion 13 side is present in the area indicated by W1 in FIG. 3B.

[0096] In this case, similarly to the solid electrolyte layer 30, the conductive layer 40 is preferably formed from the cathode 14 side to an area of ​​at least one-third but not more than three-quarters of the width of the insulator layer 20 (see the area indicated by W2 in FIG. 3B ), and more preferably formed from the cathode 14 side to an area of ​​more than one-half but not more than three-quarters of the width of the insulator layer 20 (see the area indicated by W3 in FIG. 3B ). That is, the end of the conductive layer 40 on the anode 13 side is preferably present in the area indicated by W2 in FIG. 3B , and more preferably present in the area indicated by W3 in FIG. 3B .

[0097] As shown in FIG. 18, the conductive layer 40 may be formed in an area not exceeding the solid electrolyte layer 30, that is, only on the solid electrolyte layer 30.

[0098] In this embodiment, too, only one of the carbon layer 41 and the conductive paste layer 42 may be formed as the conductive layer 40 .

[0099] Thereafter, the same procedures as in the first embodiment are carried out to fabricate a solid electrolytic capacitor 104 as shown in FIG.

[0100] 19 , the solid electrolytic capacitor 104 according to the fourth embodiment of the present invention includes a conductive layer 40 provided on the solid electrolyte layer 30, the conductive layer 40 extending from the cathode portion 14 side of the element to an area equal to or less than three-quarters of the width of the insulator layer 20. Therefore, as described above, the equivalent series resistance can be further reduced.

[0101] In the above embodiment, a pair of lead frames drawn out from a pair of end faces are used as a pair of terminals (external electrodes) electrically connected to the anode and cathode of each solid electrolytic capacitor element, respectively. However, in the solid electrolytic capacitor of the present invention, a pair of electrode layers formed on a pair of end faces, respectively, may also be used as a pair of terminals (external electrodes).

[0102] Although the above embodiment describes a chip-type solid electrolytic capacitor, the solid electrolytic capacitor of the present invention may be used by being embedded in a package substrate included in a semiconductor device, for example, such as a semiconductor composite device in which a voltage regulator (voltage control device) and a load are mounted on a package substrate.

[0103] The present specification discloses the following:

[0104] <1> A method for manufacturing a solid electrolytic capacitor, comprising: a first step of forming an insulator layer between an anode portion and a cathode portion of an anode body; and a second step of forming a solid electrolyte layer by printing or transferring from the cathode portion side to an area not exceeding the insulator layer.

[0105] <2> The method for manufacturing a solid electrolytic capacitor according to <1>, wherein in the second step, the solid electrolyte layer is formed from the cathode portion side of the element to an area of ​​¾ or less of the width of the insulator layer.

[0106] <3> The method for manufacturing a solid electrolytic capacitor according to <2>, further comprising forming a conductive layer on the solid electrolyte layer to an extent of not more than ¾ of the width of the insulator layer from the cathode portion side of the element.

[0107] <4> The method for manufacturing a solid electrolytic capacitor according to any one of <1> to <3>, wherein in the second step, the solid electrolyte layer is formed from the cathode portion side of the element to an area that is at least one-third of the width of the insulator layer.

[0108] <5> The method for manufacturing a solid electrolytic capacitor according to <4>, wherein in the second step, the solid electrolyte layer is formed from the cathode portion side of the element to an area exceeding half the width of the insulator layer.

[0109] <6> The method for manufacturing a solid electrolytic capacitor according to any one of <1> to <5>, wherein the second step includes: forming a first solid electrolyte layer only on the cathode portion of the element so that an oxide film is exposed between the first solid electrolyte layer and the insulator layer; and forming a second solid electrolyte layer by printing or transferring from the cathode portion side to an area that is ¾ or less of a width of the insulator layer; and forming the second solid electrolyte layer continuously from a part of the first solid electrolyte layer to a part of the insulator layer so as to cover the exposed part of the oxide film.

[0110] <7> The method for manufacturing a solid electrolytic capacitor according to any one of <1> to <6>, wherein the second step includes: forming a solid electrolyte layer by printing or transferring from the cathode portion side of the element to an area exceeding three-quarters of a width of the insulator layer; and removing the solid electrolyte layer from the cathode portion side of the element to an area exceeding three-quarters of the width of the insulator layer and roughening a surface of the insulator layer.

[0111] <8> A solid electrolytic capacitor comprising: an anode body; an insulator layer provided between an anode portion and a cathode portion of the anode body; and a solid electrolyte layer provided from the cathode portion side to an area exceeding one-half but not exceeding three-quarters of the width of the insulator layer.

[0112] <9> The solid electrolytic capacitor according to <8>, wherein the solid electrolyte layer includes a first solid electrolyte layer and a second solid electrolyte layer, the first solid electrolyte layer being provided only in the cathode portion of the element, away from the insulator layer, and the second solid electrolyte layer being provided from the cathode portion of the element to an area exceeding one-half to not more than three-quarters of the width of the insulator layer, and being provided continuously from a part of the first solid electrolyte layer to a part of the insulator layer so as to cover an oxide film between the first solid electrolyte layer and the insulator layer.

[0113] <10> The solid electrolytic capacitor according to <8> or <9>, wherein the surface of the insulator layer is roughened in an area exceeding three-quarters of the width of the insulator layer from the cathode portion side of the element.

[0114] <11> The solid electrolytic capacitor according to any one of <8> to <10>, further comprising a conductive layer provided on the solid electrolyte layer, the conductive layer extending from the cathode side of the element to a range of ¾ or less of the width of the insulator layer.

[0115] REFERENCE SIGNS LIST 10 Anode body 10A Assembly of anode bodies 11 Metal substrate portion 12 Porous portion 13 Element anode portion 14 Element cathode portion 15 Exposed portion of oxide film 20 Insulator layer 30 Solid electrolyte layer 31 First solid electrolyte layer 32 Second solid electrolyte layer 40 Conductive layer 41 Carbon layer 42 Conductive paste layer 51, 52, 53, 54 Solid electrolytic capacitor element 61 Anode lead frame 62 Cathode lead frame 70 Conductive adhesive 80 Sealing resin 101, 102, 103, 104 Solid electrolytic capacitor 200 Roller transfer device 220A Vertical conveying type roller transfer portion 221 Conveying roller 222 Roller (transfer roller) 223 Dispenser 224 Squeegee

Claims

1. A method for manufacturing a solid electrolytic capacitor, comprising: a first step of forming an insulator layer between the anode portion and cathode portion of an anode body; and a second step of forming a solid electrolyte layer by printing or transferring from the cathode portion side to an area not extending beyond the insulator layer.

2. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein in the second step, the solid electrolyte layer is formed from the cathode side of the element to an area of ​​3 / 4 or less of the width of the insulator layer.

3. The method for manufacturing a solid electrolytic capacitor according to claim 2, wherein a conductive layer is formed on the solid electrolyte layer from the cathode side of the element to an extent of 3 / 4 or less of the width of the insulator layer.

4. The method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 3, wherein in the second step, the solid electrolyte layer is formed from the cathode side of the element to an extent of at least 1 / 3 of the width of the insulator layer.

5. The method for manufacturing a solid electrolytic capacitor according to claim 4, wherein in the second step, the solid electrolyte layer is formed from the cathode side of the element to an extent exceeding half the width of the insulator layer.

6. The method for producing a solid electrolytic capacitor according to any one of claims 1 to 5, wherein the second step includes the steps of: forming a first solid electrolyte layer only on the cathode portion of the element so that an oxide film is exposed between the first solid electrolyte layer and the insulator layer; and forming a second solid electrolyte layer by printing or transferring from the cathode portion side of the element to an area that is 3 / 4 or less of the width of the insulator layer; and forming the second solid electrolyte layer continuously from a part of the first solid electrolyte layer to a part of the insulator layer so as to cover the exposed part of the oxide film.

7. A method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 6, wherein the second step includes the steps of: forming a solid electrolyte layer by printing or transferring from the cathode side of the element to an area exceeding 3 / 4 of the width of the insulator layer; and removing the solid electrolyte layer from the cathode side of the element to an area exceeding 3 / 4 of the width of the insulator layer and roughening the surface of the insulator layer.

8. A solid electrolytic capacitor comprising: an anode body; an insulator layer provided between an anode portion and a cathode portion of the anode body; and a solid electrolyte layer provided from the cathode portion side to an area exceeding one-half but not exceeding three-quarters of the width of the insulator layer.

9. The solid electrolytic capacitor according to claim 8, wherein the solid electrolyte layer includes a first solid electrolyte layer and a second solid electrolyte layer, the first solid electrolyte layer being provided only on the cathode portion of the element, away from the insulator layer, and the second solid electrolyte layer being provided from the cathode portion of the element to an area exceeding one-half to not more than three-quarters of the width of the insulator layer, and being provided continuously from a portion of the first solid electrolyte layer to a portion of the insulator layer so as to cover an oxide film between the first solid electrolyte layer and the insulator layer.

10. The solid electrolytic capacitor according to claim 8 or 9, wherein the surface of the insulating layer is roughened in an area exceeding 3 / 4 of the width of the insulating layer from the cathode side of the element.

11. The solid electrolytic capacitor according to any one of claims 8 to 10, further comprising a conductive layer provided on the solid electrolyte layer, the conductive layer extending from the cathode side of the element to an area of ​​not more than 3 / 4 of the width of the insulating layer.

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