Manufacturing method for electronic components

Abstract

A method for manufacturing an electronic component 1 according to the present invention comprises: a step for preparing electronic component element bodies 9 in each of which an inner electrode 3 is provided and the inner electrode 3 is exposed from an outer surface 9a thereof; and a first electrode layer formation step for forming a first electrode layer 11a by jetting metal fine particles 53 to the outer surface 9a of each of the electronic component element bodies 9 so as to cause the particles to be collided with the outer surface 9a, in a state where the pressure is lower than the atmospheric pressure.

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an electronic component. [Background technology]

[0002] Patent Document 1 discloses a chip-type capacitor. In Patent Document 1, a metal film is formed by plating on the exposed portion where the internal electrode provided inside the chip substrate is exposed, and then a conductive resin paste is applied to the exposed surface to form a side electrode.

[0003] Patent Document 2 discloses a solid electrolytic capacitor. Patent Document 2 discloses that a portion of the anode body is exposed to the outside of the sealing body, and that the exposed portion is covered with a plating layer and electrically connected to the anode conductive elastic body via the plating layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-073883 A [Patent Document 2] Patent No. 3276113 Summary of the Invention [Problem to be solved by the invention]

[0005] In the techniques described in Patent Documents 1 and 2, a plating process is used as a means for connecting an internal electrode to an external electrode. The plating process requires immersion in a plating solution, but leakage current (LC) defects can occur if the plating solution gets into unintended locations. Furthermore, the inclusion of a plating process increases the number of steps, making the manufacturing process complicated.

[0006] Therefore, an object of the present invention is to provide a method for manufacturing electronic components that can suppress the occurrence of LC defects and has a simple manufacturing process. [Means for solving the problem]

[0007] The method for manufacturing an electronic component of the present invention is characterized by comprising the steps of: preparing an electronic component body having an internal electrode, the internal electrode being exposed from its outer surface; and forming a first electrode layer by spraying and colliding metal microparticles onto the outer surface of the electronic component body at a pressure less than atmospheric pressure, thereby forming a first electrode layer. Effect of the Invention

[0008] According to the present invention, it is possible to provide a method for manufacturing an electronic component, which can suppress the occurrence of LC defects and has a simple manufacturing process. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view illustrating a schematic example of an electrolytic capacitor. [Diagram 2] FIG. 2 is a cross-sectional view of the electrolytic capacitor shown in FIG. 1 taken along line AA. [Diagram 3] FIG. 3 is a cross-sectional view that typically shows the vicinity of the valve metal base on the first end surface of the resin molded body. [Figure 4] FIG. 4 is a cross-sectional view that illustrates a schematic view of the vicinity of the cathode extraction layer on the second end face of the resin molded body. [Diagram 5] FIG. 5 is a cross-sectional view that illustrates an example of a resin molded body. [Figure 6] FIG. 6 is a schematic diagram showing a process of forming a first electrode layer by an aerosol deposition method. [Figure 7] FIG. 7 is a cross-sectional view illustrating a schematic diagram of another example of the electrolytic capacitor. [Figure 8] FIG. 8 is a cross-sectional view illustrating an example of a multilayer ceramic electronic component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The method for producing an electronic component of the present invention will now be described. However, the present invention is not limited to the following configurations, and can be modified and applied as appropriate within the scope of the present invention. Note that the present invention also includes a combination of two or more of the preferred configurations of each embodiment of the present invention described below.

[0011] First, an electrolytic capacitor will be described as an example of an object manufactured by the electronic component manufacturing method of the present invention. In this case, it is preferable that the electronic component base body constituting the electronic component is a resin molded body comprising a laminate including a capacitor element and a sealing resin that seals the periphery of the laminate, and that the capacitor element includes an anode having a valve action metal base with a dielectric layer formed on its surface, and a cathode facing the anode, and that the anode and the cathode are the internal electrodes.

[0012] FIG. 1 is a perspective view illustrating a schematic example of an electrolytic capacitor. FIG. 1 shows a resin molded body 9 that constitutes the electrolytic capacitor 1. The shape of the resin molded body constituting the electrolytic capacitor is not particularly limited, and any three-dimensional shape can be adopted. The shape of the resin molded body is preferably a rectangular parallelepiped. Moreover, the term "rectangular parallelepiped" does not mean a perfect rectangular parallelepiped, and the surface forming the resin molded body may be tapered and not perpendicular to other surfaces, and the corners may be chamfered.

[0013] FIG. 1 shows a resin molded body 9 in the shape of a rectangular parallelepiped. The resin molded body 9 has a length direction (L direction), a width direction (W direction), and a thickness direction (T direction). The resin molded body 9 has, as its outer surfaces, a first end face 9a and a second end face 9b facing each other in the length direction. An anode external electrode 11 is formed on the first end face 9a, and a cathode external electrode 13 is formed on the second end face 9b. The resin molded body 9 has, as its outer surfaces, a bottom surface 9c and a top surface 9d which face each other in the thickness direction. Moreover, the resin molded body 9 has, as its outer surfaces, a first side surface 9e and a second side surface 9f which face each other in the width direction. The resin molded body corresponds to the electronic component body in the method for producing an electronic component of the present invention.

[0014] In this specification, the surface along the length direction (L direction) and thickness direction (T direction) of the electrolytic capacitor or resin molding is referred to as the LT surface, the surface along the length direction (L direction) and width direction (W direction) is referred to as the LW surface, and the surface along the width direction (W direction) and thickness direction (T direction) is referred to as the WT surface. In the following description, the surface of the outer surface of the resin molded body on which the anode external electrode is provided will be referred to as a first end surface, and the surface on which the cathode external electrode is provided will be referred to as a second end surface. Note that the anode external electrode and the cathode external electrode may be provided on the same surface of the outer surface of the resin molded body.

[0015] FIG. 2 is a cross-sectional view of the electrolytic capacitor shown in FIG. 1 taken along line AA. Capacitor element 20 includes an anode 3 having a dielectric layer 5 on its surface, and a cathode 7 facing anode 3 . A plurality of capacitor elements 20 are stacked to form a laminate 30, and the periphery of the laminate 30 is sealed with a sealing resin 8 to form a resin molded body 9. In the laminate 30, the stacked capacitor elements 20 may be bonded to each other via a conductive adhesive (not shown). The laminate 30 may include only one capacitor element 20. An anode external electrode 11 is formed on a first end surface 9a of the resin molded body 9, and the anode external electrode 11 is electrically connected to the anode 3 exposed from the first end surface 9a. A cathode external electrode 13 is formed on the second end surface 9b of the resin molded body 9, and the cathode external electrode 13 is electrically connected to the cathode 7 exposed from the second end surface 9b. The end of the valve metal base 4 constituting the capacitor element 20 on the side of the second end face 9b is sealed with a sealing resin 8, and the valve metal base 4 is not in direct contact with the solid electrolyte layer 7a or the conductive layer 7b. On the other hand, if the end of the valve metal base 4 on the side of the second end face 9b is covered with a dielectric layer 5 or otherwise insulated, the end of the valve metal base 4 on the side of the second end face 9b may be covered with the solid electrolyte layer 7a and the conductive layer 7b.

[0016] FIG. 3 is a cross-sectional view that typically shows the vicinity of the valve metal base on the first end surface of the resin molded body. FIG. 3 is also a cross-sectional view that diagrammatically illustrates the area surrounded by the dotted line in the lower left portion of FIG. The valve metal substrate 4 has a core portion 4a and a porous portion 4b formed along the surface of the core portion 4a. An end portion of the valve metal substrate 4 is exposed at a first end surface 9a of the resin molded body 9. A dielectric layer 5 is formed on the surface of the porous portion 4b.

[0017] Examples of the valve metal constituting the valve metal substrate include simple metals such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, silicon, etc., and alloys containing these metals. Among these, aluminum or an aluminum alloy is preferred.

[0018] The shape of the valve metal substrate is not particularly limited, but is preferably a flat plate, more preferably a foil, and the porous portion is preferably an etching layer that has been etched with hydrochloric acid or the like. The thickness of the valve metal base before etching is preferably 60 μm or more and preferably 180 μm or less. Furthermore, the thickness of the valve metal base (core portion) that is not etched after etching is preferably 10 μm or more and preferably 70 μm or less. The thickness of the porous portion is designed according to the withstand voltage and electrostatic capacitance required for the electrolytic capacitor, and the combined thickness of the porous portions on both sides of the valve metal base is preferably 10 μm or more and preferably 120 μm or less.

[0019] The dielectric layer is preferably made of an oxide film of the valve metal. For example, when an aluminum foil is used as the valve metal substrate, an oxide film serving as the dielectric layer can be formed by anodizing in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or a sodium salt or ammonium salt thereof. The dielectric layer is formed along the surface of the porous portion to form pores (recesses). The thickness of the dielectric layer is designed according to the withstand voltage and capacitance required for the electrolytic capacitor, but is preferably 3 nm or more and 200 nm or less.

[0020] The anode external electrode 11 is provided on a first end surface 9a of the resin molded body 9. The anode external electrode 11 includes a first electrode layer 11a in direct contact with the core portion 4a of the valve metal base 4. The first electrode layer 11a is formed in a first electrode layer forming step in the method for manufacturing an electronic component of the present invention.

[0021] In a cross section including the first electrode layer, which is perpendicular to the main surface of the valve metal base and the outer surface of the resin molded body (the first end surface of the resin molded body), the cross section of the first electrode layer is preferably wedge-shaped. Fig. 3 shows the cross section of the first electrode layer 11a being wedge-shaped. In this specification, the wedge shape means a shape having a bottom that contacts the valve metal base in the above-mentioned cross-sectional shape, and a width perpendicular to the direction away from the bottom (height direction) that gradually narrows. The shape of the top of the wedge is not particularly limited, and may be pointed, rounded, or flat. In addition, the top of the wedge may appear roughly smooth, but may have irregularities when viewed microscopically.

[0022] The first electrode layer 11a is preferably an electrode layer containing at least one selected from the group consisting of Cu, Ni, Sn, Ag, Zn, and Au, and is particularly preferably an electrode layer containing at least one of Cu and Ni.

[0023] The first electrode layer 11a is preferably an electrode layer formed by an aerosol deposition method on the first end face 9a, which is the outer surface of the resin molded body 9. The method of forming the first electrode layer by an aerosol deposition method will be described later.

[0024] It is preferable that the anode external electrode 11 further includes a second electrode layer 11b formed on the first electrode layer 11a. The second electrode layer 11b can be formed by a second electrode layer forming step in the manufacturing method of the electronic component of the present invention. The second electrode layer 11b is preferably a conductive resin electrode layer containing a conductive component and a resin component.

[0025] An outer plating layer may be provided on the surface of the second electrode layer 11b. Fig. 2 shows a third electrode layer 11c which is an outer plating layer provided on the surface of the second electrode layer 11b. The third electrode layer is preferably a Ni-plated layer or a Sn-plated layer. When the third electrode layer has two layers, the third electrode layer may have a first outer layer plating layer formed on the surface of the second electrode layer, and a second outer layer plating layer formed on the surface of the first outer layer plating layer. The first outer plating layer is preferably a Ni plating layer, and the second outer plating layer is preferably a Sn plating layer.

[0026] Up to this point, the configuration related to the anode 3 has been described. Next, the configuration related to the cathode 7 and other components constituting the resin molded body will be described with reference to FIG.

[0027] The cathode 7 constituting the capacitor element 20 is formed by laminating a solid electrolyte layer 7a formed on the dielectric layer 5, a conductive layer 7b formed on the solid electrolyte layer 7a, and a cathode extraction layer 7c formed on the conductive layer 7b. An electrolytic capacitor in which a solid electrolyte layer is provided as part of the cathode can be said to be a solid electrolytic capacitor.

[0028] Examples of materials constituting the solid electrolyte layer include conductive polymers having a skeleton of pyrroles, thiophenes, anilines, etc. Examples of conductive polymers having a skeleton of thiophenes include PEDOT [poly(3,4-ethylenedioxythiophene)], which may be PEDOT:PSS complexed with polystyrene sulfonic acid (PSS) as a dopant.

[0029] The solid electrolyte layer is formed, for example, by a method of forming a polymerized film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or a method of applying a dispersion liquid of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric layer and drying it, etc. Note that it is preferable to form a solid electrolyte layer for an outer layer that covers the entire dielectric layer after forming a solid electrolyte layer for an inner layer that fills the pores (recesses). The solid electrolyte layer can be formed in a predetermined region by applying the above-mentioned treatment liquid or dispersion onto the dielectric layer by sponge transfer, screen printing, spray application, dispenser, inkjet printing, etc. The thickness of the solid electrolyte layer is preferably 2 μm or more and 20 μm or less.

[0030] The conductive layer is provided to electrically and mechanically connect the solid electrolyte layer and the cathode lead layer. For example, it is preferably a carbon layer, a graphene layer, a silver layer, a copper layer, a nickel layer, or the like formed by applying a conductive paste such as carbon paste, graphene paste, silver paste, copper paste, nickel paste, or the like. It may also be, for example, a composite layer in which a silver layer, a copper layer, or a nickel layer is provided on a carbon layer or a graphene layer, or a mixed layer formed by applying a mixed paste in which a carbon paste or a graphene paste is mixed with a silver paste, a copper paste, or a nickel paste.

[0031] The conductive layer can be formed by applying a conductive paste such as carbon paste to the solid electrolyte layer by sponge transfer, screen printing, spray coating, dispenser, inkjet printing, or the like. It is preferable to laminate the cathode lead layer in the next step while the conductive layer is still in a viscous state before drying. The thickness of the conductive layer is preferably 2 μm or more and 20 μm or less.

[0032] The cathode extraction layer can be formed of a metal foil. In the case of a metal foil, it is preferable that the metal foil is made of at least one metal selected from the group consisting of Al, Cu, Ag, and alloys mainly composed of these metals. When the metal foil is made of the above metals, the resistance value of the metal foil can be reduced, and the equivalent series resistance (ESR) can be reduced. The metal foil may be a metal foil whose surface is coated with carbon or titanium by a film forming method such as sputtering or vapor deposition. It is more preferable to use a carbon-coated Al foil. The thickness of the metal foil is not particularly limited, but from the viewpoints of handling in the manufacturing process, miniaturization, and reducing ESR, it is preferably 20 μm or more and preferably 50 μm or less.

[0033] FIG. 4 is a cross-sectional view that illustrates a schematic view of the vicinity of the cathode extraction layer on the second end face of the resin molded body. FIG. 4 is also a cross-sectional view that diagrammatically illustrates the area surrounded by the dotted line in the lower right portion of FIG. Cathode extraction layer 7c, which is a metal foil, is exposed at second end surface 9b of resin molded body 9.

[0034] The cathode external electrode 13 is provided on the second end face 9b which is the outer surface of the resin molded body 9. The cathode external electrode 13 may include a first electrode layer 13a in direct contact with the cathode lead layer 7c. The first electrode layer 13a may have a similar configuration to the first electrode layer 11a formed on the first end surface 9a of the resin molded body 9. In a cross section including the first electrode layer, which is perpendicular to the main surface of the cathode lead layer and the outer surface of the resin molded body (the second end face of the resin molded body), the cross section of the first electrode layer is preferably wedge-shaped. Fig. 4 shows a cross section of the first electrode layer 13a that is wedge-shaped.

[0035] Similar to the anode external electrode 11, the cathode external electrode 13 may include a second electrode layer 13b formed on a first electrode layer 13a, and may also include a third electrode layer 13c. The second electrode layer 13b and the third electrode layer 13c may have the same configuration as the second electrode layer 11b and the third electrode layer 11c in the anode external electrode 11.

[0036] The sealing resin 8 constituting the resin molded body 9 contains at least a resin, and preferably contains a resin and a filler. As the resin, it is preferable to use an insulating resin such as an epoxy resin, a phenol resin, a polyimide resin, a silicone resin, a polyamide resin, or a liquid crystal polymer. The resin molded body 9 may be composed of two or more kinds of insulating resins. The sealing resin 8 may be in the form of either a solid resin or a liquid resin. As the filler, it is preferable to use inorganic particles such as silica particles, alumina particles, or metal particles. It is more preferable to use a material containing silica particles in a solid epoxy resin and a phenol resin. As a molding method of the resin molded body, when a solid sealing material is used, it is preferable to use a resin mold such as a compression mold or a transfer mold, and it is more preferable to use a compression mold. When a liquid sealing material is used, it is preferable to use a molding method such as a dispensing method or a printing method. It is preferable to seal a laminate 30 of a capacitor element 20 consisting of an anode 3, a dielectric layer 5, and a cathode 7 with a sealing resin 8 by compression molding to form a resin molded body 9.

[0037] Next, a method for manufacturing an electronic component according to the present invention will be described using the case of manufacturing such an electrolytic capacitor as an example. In the method for manufacturing an electronic component of the present invention, an electronic component element having internal electrodes exposed from its outer surface is prepared. In the electrolytic capacitor shown in Fig. 2, resin molded body 9 corresponds to the electronic component element. In the following, an embodiment will be described in which an anode is exposed from the outer surface of a resin molded body serving as an electronic component base body, and a first electrode layer formation process is performed on the outer surface of the resin molded body where the anode is exposed, with the outer surface of the resin molded body where the anode is exposed being referred to as a first end face. FIG. 5 is a cross-sectional view that illustrates an example of a resin molded body.

[0038] In the first electrode layer forming step, metal particles are sprayed and collided at a pressure lower than atmospheric pressure onto a first end face, which is the outer surface of the electronic component body, to form the first electrode layer. By forming the first electrode layer through this process, the external electrodes can be formed without using a plating process that is prone to causing corrosion of the internal electrodes, thereby making it possible to suppress LC defects caused by the plating solution.

[0039] The method for forming the first electrode layer is preferably aerosol deposition, gas deposition, etc. In particular, it is preferable to form the first electrode layer on the outer surface of the electronic component body by aerosol deposition. FIG. 6 is a schematic diagram showing a process of forming a first electrode layer by an aerosol deposition method. 6 shows an aerosol deposition apparatus 51. The aerosol deposition apparatus 51 has a cylinder containing carrier gas 52, an aerosol generator 54 into which carrier gas 52 and metal fine particles 53 are introduced to generate an aerosol, a chamber 55 into which the aerosol is introduced, and a stage 57 on which electronic component bodies 9 are fixed and arranged with their first end faces 9a facing up. In the aerosol deposition method, metal particles 53 are sprayed from a nozzle 56 attached to the tip of an aerosol generator 54, and collide with a first end face 9a of an electronic component body 9 to form a first electrode layer. By forming the first electrode layer by the aerosol deposition method, the thickness of the first electrode layer can be reduced and the bonding strength between the electronic component body and the first electrode layer can be increased. Furthermore, the aerosol deposition method allows the film to be formed at a slow film formation speed and a low temperature, which reduces damage to the electronic component body.

[0040] The first electrode layer forming process is carried out under a pressure lower than atmospheric pressure. The pressure inside the chamber can be made lower than atmospheric pressure by evacuating the chamber. The pressure inside the chamber is preferably 10 Pa or more and 1000 Pa or less. The pressure inside the chamber can be adjusted by increasing or decreasing the gas flow rate. When the gas flow rate is increased so that the pressure inside the chamber becomes, for example, 100 Pa or more, the film formation speed can be increased, and as a result, the film formation cost can be reduced.

[0041] The first electrode layer forming step is preferably carried out at a temperature of 100° C. or less, and more preferably at room temperature. Since there is no need to raise the temperature, damage to the electronic component body can be reduced, and carrying out the step at room temperature allows the use of simple equipment. The normal temperature may be the temperature of the working environment, and may be, for example, 10°C or higher and 30°C or lower.

[0042] The metal fine particles are preferably fine particles containing at least one selected from the group consisting of Cu, Ni, Sn, Ag, Zn and Au, and more preferably fine particles containing at least one of Cu and Ni. By changing the particle size of the metal particles, the scanning speed of the nozzle, and the amount of metal particles ejected per unit time, it is possible to adjust the ease of adhesion of the metal particles and the thickness of the first electrode layer. From the viewpoint of ease of attachment of the metal fine particles and the thickness of the first electrode layer, the particle size of the metal fine particles is preferably D50 less than 5 μm, and more preferably D50 less than 3 μm. D50 of metal particles is the volume distribution based median diameter measured by laser diffraction / scattering method. As a measuring device for D50 of metal particles, for example, MT3300 manufactured by Microtrack Bell Corporation can be used.

[0043] In the first electrode layer forming step, it is preferable to form the first electrode layer with a thickness of 0.1 μm or more and 30 μm or less. It is more preferable to form the first electrode layer with a thickness of 1.0 μm or more and 30 μm or less. If the thickness of the first electrode layer is within the above range, the ESR of the electrolytic capacitor can be reduced, and the adhesion between the first electrode layer and the electronic component body can also be increased. The thickness of the first electrode layer may be measured at the thickest point in a cross-sectional photograph including the first electrode layer as shown in FIG.

[0044] After the first electrode layer is formed, a second electrode layer forming step may be performed in which a second electrode layer containing a conductive component and a resin component is formed on the first electrode layer. In the second electrode layer forming step, it is preferable to perform screen printing of an electrode paste to form a printed resin electrode layer as the second electrode layer. When the second electrode layer is formed by screen printing the electrode paste, the external electrodes can be made flatter than when the electrode paste is formed by dipping, which improves the uniformity of the film thickness of the external electrodes.

[0045] The conductive component preferably contains Ag, Cu, Ni, Sn or the like as a main component, and the resin component preferably contains epoxy resin, phenol resin or the like as a main component. In particular, it is preferable to form a conductive resin electrode layer containing Ag as the second electrode layer, since the specific resistance of Ag in the conductive resin electrode layer containing Ag can reduce the ESR.

[0046] The electrode paste may contain an organic solvent, and as the organic solvent, it is preferable to use a glycol ether-based solvent, such as diethylene glycol monobutyl ether or diethylene glycol monophenyl ether. If necessary, additives may be used. The additives are useful for adjusting the rheology of the electrode paste, particularly the thixotropy. The content of the additives is preferably less than 5% by weight based on the weight of the electrode paste.

[0047] After the second electrode layer is formed, a third electrode layer forming step may be performed in which a third electrode layer is formed on the second electrode layer by plating. If the first electrode layer is formed in advance on the electronic component body, LC defects are less likely to occur even if the third electrode layer is subsequently formed by plating.

[0048] Alternatively, a third electrode layer forming step may be performed in which a third electrode layer is formed by plating on the first electrode layer without forming a second electrode layer. In this case as well, if the first electrode layer is formed in advance on the electronic component body, LC defects are less likely to occur even if the third electrode layer is subsequently formed by plating.

[0049] The second end face of the electronic component body may also be subjected to the first electrode layer forming step in the same manner as for the first end face of the electronic component body, to form a first electrode layer on the second end face. This step makes it possible to form a first electrode layer 13a as shown in FIG. 4 on the second end face 9b of the electronic component body. Thereafter, the second electrode layer 13b and the third electrode layer 13c can be formed in the same manner as on the first end face side of the electronic component body. In particular, when the cathode extraction layer is a metal foil, providing the first electrode layer in the first electrode layer formation step is effective because it can improve the adhesion between the metal foil and the first electrode layer.

[0050] The method for producing an electronic component of the present invention can be used for producing the electrolytic capacitor described above as an electronic component, but can also be used for producing other types of electrolytic capacitors and multilayer ceramic electronic components. Examples of these are described below.

[0051] FIG. 7 is a cross-sectional view illustrating a schematic diagram of another example of the electrolytic capacitor. In the electrolytic capacitor 2 shown in FIG. 7, the cathode lead layer 7c and the cathode lead portion 7d are formed from an electrode paste rather than a metal foil. In this case, the electrode paste is applied onto the conductive layer by sponge transfer, screen printing, spray coating, dispenser, inkjet printing, or the like to form the cathode lead layer in a predetermined region. As the electrode paste, an electrode paste containing Ag, Cu, or Ni as a main component is preferable. When the cathode lead layer is formed by the electrode paste, the thickness of the cathode lead layer can be made thinner than when a metal foil is used, and in the case of screen printing, the thickness can be made 2 μm or more and 20 μm or less.

[0052] When cathode lead layer 7c and cathode lead portion 7d are formed using electrode paste, second electrode layer 13b can be formed by screen printing of the electrode paste without providing a first electrode layer on the cathode side.

[0053] Cathode lead layers 7c of capacitor elements 20 are gathered together in the vicinity of second end face 9b as cathode lead portion 7d and exposed to second end face 9b. Cathode lead portion 7d may be formed from the same electrode paste as cathode lead layer 7c, or the electrode pastes constituting cathode lead portion 7d and cathode lead layer 7c may have different compositions. When cathode lead layer 7c and cathode lead portion 7d are formed from electrode paste, they have good adhesion to second electrode layer 13b formed by screen printing of the electrode paste.

[0054] Further, although not shown in Fig. 7, an insulating mask may be provided on the anode side. In that case, the insulating mask may be provided on the surface of the dielectric layer.

[0055] In another example of the electrolytic capacitor shown in Fig. 7, the above-mentioned treatment liquid or dispersion liquid may be applied to the dielectric layer by dipping to form a solid electrolyte layer in a predetermined region. Similarly, a conductive paste such as a carbon paste may be applied to the solid electrolyte layer by dipping to form a conductive layer.

[0056] Similarly, the first electrode layer forming step is performed on the first end surface of the electronic component body as shown in FIG. 7 to form a first electrode layer. Furthermore, a second electrode layer forming step and a third electrode layer forming step may be carried out.

[0057] In the method for producing an electronic component of the present invention, the electronic component element may be a rectangular parallelepiped laminate in which at least one ceramic layer selected from the group consisting of a dielectric ceramic layer, a magnetic ceramic layer, a piezoelectric ceramic layer, and a semiconductor ceramic layer and an internal electrode layer are laminated, and the internal electrode layer is an internal electrode. In this configuration, the electronic component is a multilayer ceramic electronic component.

[0058] Examples of multilayer ceramic electronic components include multilayer ceramic capacitors, multilayer coils, multilayer thermistors, multilayer varistors, multilayer LC filters, multilayer piezoelectric filters, etc. Below, a multilayer ceramic capacitor will be described as an example of a multilayer ceramic electronic component.

[0059] FIG. 8 is a cross-sectional view illustrating an example of a multilayer ceramic electronic component. The multilayer ceramic capacitor 101 includes a laminate 109 in which a dielectric ceramic layer 108, an internal electrode layer 103, and an internal electrode layer 105 are laminated. The laminate 109 corresponds to an electronic component body. The shape of the laminate constituting the multilayer ceramic electronic component is not particularly limited, and any three-dimensional shape can be adopted. The shape of the laminate is preferably a rectangular parallelepiped. Moreover, the term "rectangular parallelepiped" does not mean that the laminate is a perfect rectangular parallelepiped, and the faces forming the laminate may be tapered and not perpendicular to other faces, and the laminate may have a shape with chamfered corners.

[0060] FIG. 8 shows a laminate 109 having a rectangular parallelepiped shape. The laminate 109 has a first end face 109a which is an outer surface, a second end face 109b, a bottom face 109c, and a top face 109d, as well as a first side face and a second side face (not shown).

[0061] The dielectric ceramic layers constituting the laminate contain a dielectric ceramic such as barium titanate, etc. The dielectric ceramic layers can be obtained by forming a dielectric slurry containing a dielectric ceramic and an organic solvent into a sheet.

[0062] The internal electrode layers constituting the laminate can be obtained by printing an electrode paste containing a conductive component. The internal electrode layers are preferably Ni electrode layers using Ni as the conductive component. Moreover, the Ni electrode layer may be replaced with an Ag electrode layer, a Pd electrode layer, or a Cu electrode layer.

[0063] By carrying out the first electrode layer forming step on the first end surface 109a of the laminate 109 as shown in FIG. 8, it is possible to form the first electrode layer 111a connected to the internal electrode layer 103 which is an internal electrode. Alternatively, a first electrode layer forming step may be performed on the second end surface 109b of the laminate 109 to form a first electrode layer 113a connected to the internal electrode layer 105 which is an internal electrode.

[0064] In addition to the first electrode layers 111a and 113a, second electrode layers 111b and 113b and third electrode layers 111c and 113c may also be formed. Through these steps, the anode external electrode 111 and the cathode external electrode 113 are formed. Furthermore, the third electrode layers 111c and 113c may be formed on the first electrode layers 111a and 113a without forming the second electrode layers 111b and 113b. EXAMPLES

[0065] The following examples are given to evaluate the LC failure, adhesion strength, and ESR of the electrolytic capacitor, which is an electronic component of the present invention. Note that the present invention is not limited to these examples.

[0066] (Examples 1 to 8) The laminate having the structure shown in FIG. 1 and FIG. 2 was sealed with a sealing resin containing an epoxy resin and silica particles to obtain a resin molded body. A first electrode layer was formed on a first end surface of the resin molded body by the aerosol deposition method (AD method). Cu particles were used as the metal fine particles, and the thickness of the first electrode layer was changed by changing the film formation conditions in the aerosol deposition method. Table 1 shows the type of metal particles (metal type) and the thickness of the first electrode layer in each example. A first electrode layer was formed on a second end surface of the resin molded body in the same manner as on the first end surface.

[0067] Then, an electrode paste containing Ag was applied to the end faces (first end face and second end face) of the resin molded body by screen printing and thermally cured to form a second electrode layer. Furthermore, a Ni plating layer and a Sn plating layer, which are the third electrode layer, were formed on the surface of the second electrode layer to produce an electrolytic capacitor.

[0068] Comparative Example 1 The first and second end faces of the resin molded body were etched with an acid mainly composed of nitric acid, and a zincate treatment was performed by forming a Zn coating. The first electrode layer was formed by Ni plating and Ag plating. The second electrode layer and the third electrode layer were formed in the same manner as in Example 1 to prepare an electrolytic capacitor. The thickness of the Ni plating layer and the Ag plating layer was 5 μm each.

[0069] [Film thickness measurement] The thickness of the first electrode layer of the electrolytic capacitor was measured non-destructively using a fluorescent X-ray film thickness gauge (SFT9450, manufactured by Hitachi High-Tech Science Corporation). The thickness obtained by this measurement method is approximately half the physical thickness measured by polishing the cross section of the LT surface of the electrolytic capacitor and using SEM / EDS. Therefore, the thickness obtained by the fluorescent X-ray film thickness gauge was considered to be twice the thickness of the first electrode layer, and is shown in Table 1.

[0070] [LC defect measurement] The rate at which LC defects occurred, that is, the LC defect rate (%), was determined for 1000 electrolytic capacitors for each of the examples and comparative examples.

[0071] [Adhesion strength measurement] The electrolytic capacitor was mounted on a glass epoxy board, and the glass epoxy board was deflected at 1 mm / sec until the displacement reached 10 mm, and then the capacitance change rate after maintaining this state for 5 seconds was measured. If the bonding strength between the first and second electrode layers is weak, peeling will occur, opening up the capacitor element and the external electrode, causing a change in capacitance. Therefore, measuring the rate of capacitance change can be used instead of measuring the adhesion strength between the first and second electrode layers. The evaluation criteria were as follows: a capacitance change rate of 5% or less was rated as excellent, a rate of change from more than 5% to less than 10% was rated as good, and a rate of change exceeding 10% was rated as poor.

[0072] [ESR measurement] The ESR (mΩ) at 100 kHz was measured using an LCR meter (KEYSIGHT E4980A). The ESR was calculated as the average value of the results of measuring 10 electrolytic capacitors. The evaluation criteria were as follows: 30 mΩ or less: ⊚ (particularly good); over 30 mΩ to 40 mΩ or less: ◯ (good); and over 40 mΩ: △ (acceptable for practical use). The results of each of these evaluation tests are shown in Table 1.

[0073] [Table 1]

[0074] In each of the Examples in which the first electrode layer was formed by the AD method, the number of LC defects was small, but in Comparative Example 1 in which the first electrode layer was formed by plating, the number of LC defects was large. When the thickness of the first electrode layer was as thin as 0.2 μm or less, the ESR was somewhat high. This is thought to be due to the fact that the formation of the first electrode layer formed on the valve metal substrate was partially insufficient. [Explanation of symbols]

[0075] 1, 2 Electrolytic capacitors (electronic components) 3 Anode 4 Valve metal substrate 4a Core 4b Porous part 5 Dielectric Layer 7 Cathode 7a Solid electrolyte layer 7b Conductive layer 7c Cathode extraction layer 7d Cathode lead-out section 8 Sealing resin 9. Resin moldings (electronic component bodies) 9a: First end surface of resin molded body (outer surface of resin molded body) 9b: second end surface of resin molded body (outer surface of resin molded body) 9c Bottom surface of resin molded body (outer surface of resin molded body) 9d Upper surface of resin molded body (outer surface of resin molded body) 9e First side surface of resin molded body (outer surface of resin molded body) 9f: second side surface of the resin molded body (outer surface of the resin molded body) 11 Anode external electrode 11a, 13a 1st electrode layer 11b, 13b second electrode layer 11c, 13c 3rd electrode layer 13 Cathode external electrode 20 Capacitor element 30 Laminate 51 Aerosol Deposition Device 52 Carrier Gas 53 Metal fine particles 54 Aerosol Generator 55 Chamber 56 Nozzle 57 Stages 101 Multilayer ceramic capacitors (electronic components) 103, 105 Internal electrode layer 108 Dielectric ceramic layer 109 Laminate (electronic component body) 109a: first end surface of laminate 109b second end surface of laminate 109c Bottom surface of stack 109d Top surface of laminate 111 Anode external electrode 111a, 113a 1st electrode layer 111b, 113b second electrode layer 111c, 113c 3rd electrode layer 113 Cathode external electrode

Claims

1. preparing an electronic component body having internal electrodes, ends of the internal electrodes being exposed from an outer surface; a first electrode layer forming step of forming a plurality of first electrode layers by injecting and colliding metal fine particles onto the outer surface of the electronic component body under a pressure lower than atmospheric pressure; the first electrode layers cover the ends of the internal electrodes and the surrounding surfaces of the electronic component body continuously and spaced apart from one another; the electronic component body is a resin molded body including a laminate including a capacitor element and a sealing resin that seals the periphery of the laminate, the capacitor element includes an anode having a valve metal base with a dielectric layer formed on its surface, and a cathode facing the anode, the anode and the cathode being internal electrodes.

2. The method for manufacturing an electronic component according to claim 1 , wherein the method for forming the first electrode layer is an aerosol deposition method.

3. The method for producing an electronic component according to claim 1 or 2, wherein the first electrode layer forming step is carried out at a temperature of 100° C. or less.

4. The method for producing an electronic component according to claim 3 , wherein the first electrode layer forming step is carried out at room temperature.

5. The method for manufacturing an electronic component according to any one of claims 1 to 4, wherein the metal fine particles have a D50 of less than 5 µm.

6. The method for producing an electronic component according to claim 5 , wherein the metal fine particles have a D50 of less than 3 μm.

7. The method for manufacturing an electronic component according to any one of claims 1 to 6, wherein the first electrode layer is formed to a thickness of 0.1 μm or more and 30 μm or less.

8. The method for manufacturing an electronic component according to claim 7 , wherein the first electrode layer is formed to a thickness of 1.0 μm or more and 30 μm or less.

9. The method for producing an electronic component according to any one of claims 1 to 8, further comprising a second electrode layer forming step of forming a second electrode layer containing a conductive component and a resin component on the first electrode layer.

10. The method for producing an electronic component according to claim 9 , further comprising a third electrode layer forming step of forming a third electrode layer on the second electrode layer by plating.

11. The method for manufacturing an electronic component according to claim 9 or 10, wherein in the second electrode layer forming step, a printed resin electrode layer is formed as the second electrode layer by screen printing an electrode paste.

12. The method for producing an electronic component according to any one of claims 1 to 8, further comprising a third electrode layer forming step of forming a third electrode layer on the first electrode layer by plating.

13. The method for manufacturing an electronic component according to any one of claims 1 to 12, wherein an end of the anode is exposed from the outer surface of the resin molded body, and the first electrode layer forming step is performed on the outer surface of the resin molded body where the end of the anode is exposed.

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