Method for manufacturing surface-mounted electronic component
Patent Information
- Application Number
- JP2024560138
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2043-11-20
AI Technical Summary
Existing methods for manufacturing surface-mounted electronic components, such as those described in Patent Documents 1 to 3, result in increased costs due to unnecessary application of electrode paste on all surfaces, poor productivity from separate screen printing on end and bottom faces, and insufficient coverage at the edge portions leading to potential conduction failures between the end and bottom surfaces.
A method involving preparing rectangular parallelepiped electronic component elements with internal conductors, arranging them to tilt during screen printing, and applying electrode paste only on the first end surface and first main surface to form external electrodes, ensuring excellent edge coverage without applying paste to all surfaces, thereby reducing costs and improving productivity.
This method allows for the efficient formation of external electrodes with superior edge coverage, reducing costs and enhancing productivity while preventing conduction failures, thus improving the manufacturing process for surface-mounted electronic components.
Abstract
Description
Manufacturing method for surface-mounted electronic components
[0001] The present invention relates to a method for manufacturing a surface-mount electronic component.
[0002] Patent Documents 1 and 2 describe a method for forming external electrodes of an electrolytic capacitor by applying electrode paste by screen printing to the end faces of a resin molded body in which multiple capacitor elements are sealed with a sealing resin, as well as the surrounding bottom, top, and side faces.
[0003] Patent Document 3 describes a method for forming external electrodes of an electrolytic capacitor by applying electrode paste by screen printing to the end faces and bottom face of a resin molded body in which multiple capacitor elements are sealed with sealing resin.
[0004] International Publication No. 2020 / 174847 Japanese Patent Application Laid-Open No. 2020-141059 Japanese Patent Application Laid-Open No. 2020-107884
[0005] In an electrolytic capacitor, the internal anode and cathode electrodes are drawn out to both end surfaces of the resin molded body, and the bottom surface is the mounting surface, so it is sufficient if the electrode paste can be printed on at least the end surfaces and bottom surface of the resin molded body.
[0006] However, in the methods described in Patent Documents 1 and 2, the electrode paste is applied to the top and side surfaces of the resin molded body (electronic component body), which increases costs accordingly.
[0007] Furthermore, the method described in Patent Document 3 requires screen printing on both the end faces and the bottom face of the resin molded body, which reduces productivity.
[0008] Furthermore, in the methods described in Patent Documents 1 to 3, the coverage of the electrode paste at the edge portion of the resin molded body is insufficient, and as a result, there is a possibility that the electrical continuity of the external electrode between the end surface and the bottom surface may be insufficient.
[0009] The present invention has been made to solve the above problems, and aims to provide a method for manufacturing a surface-mounted electronic component that can easily form external electrodes that have excellent coverage at the edge portions of the electronic component body.
[0010] The method for manufacturing a surface-mounted electronic component of the present invention includes: an element preparation step of preparing a rectangular parallelepiped electronic component element having an internal conductor, and having first and second main surfaces opposing each other in the height direction, first and second side surfaces opposing each other in the width direction, and first and second end surfaces opposing each other in the length direction; an element placement step of placing the electronic component element so that the first end surfaces and the second end surfaces face up and down; and an electrode formation step of screen-printing an electrode paste on the first end surfaces and the first main surfaces while tilting the electronic component element toward the second main surface, thereby forming external electrodes on the first end surfaces and the first main surfaces.
[0011] According to the present invention, it is possible to provide a method of manufacturing a surface-mounted electronic component that can easily form external electrodes that have excellent coverage at the edge portions of the electronic component body.
[0012] FIG. 1 is a perspective view schematically illustrating an example of an electronic component element according to a first embodiment of the present invention. FIG. 2 is an example of a cross-sectional view taken along line A-A of the electronic component element shown in FIG. 1, showing a resin molded body constituting an electrolytic capacitor. FIG. 3 is another example of a cross-sectional view taken along line A-A of the electronic component element shown in FIG. 1, showing a resin molded body constituting an electrolytic capacitor. FIG. 4 is another example of a cross-sectional view taken along line A-A of the electronic component element shown in FIG. 1, showing a laminate constituting a multilayer ceramic capacitor. FIG. 5 is an exploded perspective view schematically illustrating an example of a step of arranging an electronic component element in a method for manufacturing a surface-mounted electronic component according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view schematically illustrating an example of a step of arranging an electronic component element in a method for manufacturing a surface-mounted electronic component according to the first embodiment of the present invention. FIG. 7 is a perspective view schematically illustrating an example of a step of forming external electrodes on the electronic component element shown in FIG. 5. FIG. 8 is a cross-sectional view schematically illustrating an example of a step (mesh coating) of forming external electrodes on the electronic component element shown in FIG. 6. FIG. 9 is a cross-sectional view schematically illustrating an example of a step (screen printing) of forming external electrodes on the electronic component element shown in FIG. 8. FIG. 10 is a cross-sectional view schematically showing an example of a step (after screen printing) of forming external electrodes on the electronic component body shown in FIG. 8 . FIG. 11 is a perspective view schematically showing an example of a surface mount electronic component produced by the method for manufacturing a surface mount electronic component according to embodiment 1 of the present invention. FIG. 12 is a first side view of the surface mount electronic component shown in FIG. 11 . FIG. 13 is a second side view of the surface mount electronic component shown in FIG. 11 . FIG. 14 is a cross-sectional view schematically showing an example of a step of arranging an electronic component body in the method for manufacturing a surface mount electronic component according to embodiment 2 of the present invention. FIG. 15 is a cross-sectional view schematically showing an example of a step (first screen printing) of forming external electrodes on the electronic component body shown in FIG. 14 . FIG. 16 is a cross-sectional view schematically showing an example of a step (after the first screen printing) of forming external electrodes on the electronic component body shown in FIG. 14 . FIG. 17 is a cross-sectional view schematically showing an example of a step (second mesh coating) of forming external electrodes on the electronic component body shown in FIG. 16 . FIG. 18 is a perspective view schematically showing an example of a step (second screen printing) of forming external electrodes on the electronic component body shown in FIG.Fig. 19 is a perspective view schematically showing an example of a step (after the second screen printing) of forming external electrodes on the electronic component body shown in Fig. 17. Fig. 20 is a perspective view schematically showing an example of a surface mount electronic component produced by the method for producing a surface mount electronic component according to embodiment 2 of the present invention. Fig. 21 is a first side view of the surface mount electronic component shown in Fig. 20. Fig. 22 is a second side view of the surface mount electronic component shown in Fig. 20.
[0013] The following describes a method for manufacturing a surface-mounted electronic component according to the present invention. However, the present invention is not limited to the following configurations, and can be modified as appropriate 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.
[0014] First Embodiment First, a method for manufacturing a surface mount electronic component according to a first embodiment of the present invention will be described.
[0015] (Element Preparation Process) FIG. 1 is a perspective view that schematically shows an example of an electronic component element according to the first embodiment of the present invention.
[0016] 1 , first, a plurality of rectangular parallelepiped electronic component bodies 10 are prepared. Each electronic component body 10 has a plurality of internal conductors 16, a first main surface 10a and a second main surface 10b facing each other in the height direction T, a first side surface 10c and a second side surface 10d facing each other in the width direction W, and a first end surface 10e and a second end surface 10f facing each other in the length direction L. The first main surface 10a is the surface on the side that will serve as the mounting surface of a surface-mount electronic component to be fabricated from the electronic component body 10.
[0017] As described above, the electronic component body 10 has a substantially rectangular parallelepiped outer shape, but the corners and ridges may be rounded. A corner is a portion where three faces of the electronic component body 10 intersect, and a ridge is a portion where two faces of the electronic component body 10 intersect.
[0018] The areas of the first main surface 10a and the second main surface 10b may be substantially the same as or different from the areas of the first side surface 10c and the second side surface 10d.
[0019] Each internal conductor 16 is exposed at either the first end face 10e or the second end face 10f.
[0020] Suitable examples of surface-mount electronic components manufactured by the manufacturing method of this embodiment include electrolytic capacitors and multilayer ceramic electronic components.
[0021] First, the internal structure of an electronic component body when manufacturing an electrolytic capacitor will be described.
[0022] FIG. 2 is an example of a cross-sectional view of the electronic component element taken along line AA shown in FIG. 1, showing a resin molded body that constitutes an electrolytic capacitor.
[0023] In this case, as shown in FIG. 2, the electronic component body 10 is a resin molded body 20 having a plurality of capacitor elements 21 and a sealing resin 22 that seals the plurality of capacitor elements 21 .
[0024] In this case, an inner plating layer may be formed on each of the first end face 10 e and the second end face 10 f. The inner plating layer may include a Ni plating layer and an Ag plating layer on the Ni plating layer.
[0025] When the internal conductors 16 contain Al, the Ni plating layer electrically connected to the internal conductors 16 is preferably formed by zincate treatment. That is, the exposed surfaces of the internal conductors 16 are alkaline etched to remove the oxide film on the internal conductors 16, and then Zn plating is performed. Next, the Ni plating layer is formed by displacement plating using electroless Ni plating.
[0026] The capacitor element 21 includes, as the internal conductor 16 , an anode 23 having a dielectric layer 25 on the surface thereof, and a cathode 27 facing the anode 23 .
[0027] A plurality of capacitor elements 21 are stacked to form laminate 28, and the periphery of laminate 28 is sealed with sealing resin 22 to form resin molded body 20. In laminate 28, stacked capacitor elements 21 may be bonded to each other via a conductive adhesive (not shown).
[0028] A first external electrode (to be described later) is electrically connected to an anode 23 exposed from the first end surface 10e, and a second external electrode (to be described later) is electrically connected to a cathode 27 exposed from the second end surface 10f.
[0029] The anode 23 has a valve metal foil 23a at the center and a porous layer (not shown) such as an etching layer on the surface thereof, and a dielectric layer 25 is provided on the surface of the porous layer.
[0030] Examples of the valve metal include simple metals such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, and silicon, as well as alloys containing these metals. Among these, aluminum and aluminum alloys are preferred.
[0031] The shape of the valve metal is not particularly limited, but is preferably a flat plate, more preferably a foil, and the porous layer is preferably an etched layer that has been etched with hydrochloric acid or the like.
[0032] The anode 23 is extended to the first end surface 10e and electrically connected to the first external electrode.
[0033] The dielectric layer 25 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 that becomes the dielectric layer 25 can be formed by anodizing the aluminum foil in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts or ammonium salts.
[0034] The dielectric layer 25 is formed along the surface of the porous layer, thereby forming pores (recesses).
[0035] The cathode 27 is formed by laminating a solid electrolyte layer 27a formed on the dielectric layer 25, a conductive layer 27b formed on the solid electrolyte layer 27a, and a cathode lead layer 27c formed on the conductive layer 27b.
[0036] Since the solid electrolyte layer 27a is provided as a part of the cathode 27, the electrolytic capacitor thus fabricated can be said to be a solid electrolytic capacitor.
[0037] Examples of materials constituting the solid electrolyte layer 27a include conductive polymers with a skeleton of pyrroles, thiophenes, anilines, etc. Examples of conductive polymers with a skeleton of thiophenes include PEDOT [poly(3,4-ethylenedioxythiophene)], which may be PEDOT:PSS composited with polystyrene sulfonic acid (PSS) as a dopant.
[0038] The solid electrolyte layer 27a is formed, for example, by a method of forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 25 using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric layer 25 and drying it. Note that it is preferable to form an inner solid electrolyte layer that fills the pores (recesses) and then form an outer solid electrolyte layer that covers the entire dielectric layer 25.
[0039] The solid electrolyte layer 27a can be formed in a predetermined region by applying the above-mentioned treatment liquid or dispersion liquid onto the dielectric layer 25 by sponge transfer, screen printing, spray coating, dispenser, inkjet printing, or the like.
[0040] The conductive layer 27b is provided to electrically and mechanically connect the solid electrolyte layer 27a and the cathode lead layer 27c. For example, the conductive layer 27b is preferably a carbon layer, a graphene layer, or a silver layer formed by applying a conductive paste such as carbon paste, graphene paste, or silver paste. Alternatively, the conductive layer 27b may be a composite layer in which a silver layer is provided on a carbon layer or a graphene layer, or a mixed layer in which a carbon paste or a graphene paste is mixed with a silver paste.
[0041] Conductive layer 27b can be formed by applying a conductive paste such as carbon paste onto solid electrolyte layer 27a by sponge transfer, screen printing, spray coating, a dispenser, inkjet printing, etc. It is preferable to laminate cathode lead layer 27c, which will be formed in the next step, on conductive layer 27b while it is still viscous before drying.
[0042] The cathode lead layer 27c can be formed of a metal foil or a printed electrode layer.
[0043] 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 containing these metals as the main component.
[0044] 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, etc. Carbon-coated Al foil is more preferably used.
[0045] In the case of a printed electrode layer, the cathode lead layer 27c can be formed in a predetermined region by applying an electrode paste to the conductive layer 27b by sponge transfer, screen printing, spray coating, a dispenser, inkjet printing, or the like. The electrode paste is preferably an electrode paste containing Ag, Cu, or Ni as a main component. When the cathode lead layer 27c is a printed electrode layer, the thickness of the printed electrode layer can be made thinner than when a metal foil is used.
[0046] The cathode lead layer 27c is led to the second end surface 10f of the resin compact 20 and electrically connected to the second external electrode.
[0047] The sealing resin 22 contains at least a resin, and preferably contains a resin and a filler. Examples of resins that can be used include epoxy resin, phenol resin, polyimide resin, silicone resin, polyamide resin, and liquid crystal polymer. The sealing resin 22 can be in the form of either a solid resin or a liquid resin. Examples of fillers that can be used include silica particles, alumina particles, and metal particles. It is more preferable to use a material that contains silica particles in a solid epoxy resin and a phenol resin.
[0048] As a molding method for resin molded body 20, when a solid encapsulant is used, it is preferable to use a resin mold such as compression molding or transfer molding, and it is more preferable to use compression molding. When a liquid encapsulant is used, it is preferable to use a molding method such as a dispensing method or a printing method. It is preferable to seal laminate 28 of capacitor elements 21 consisting of anode 23, dielectric layer 25, and cathode 27 with sealing resin 22 by compression molding to form resin molded body 20.
[0049] A support substrate 29 is provided on the bottom of the resin molded body 20 , and the bottom surface of the support substrate 29 forms the first main surface 10 a of the electronic component body 10 .
[0050] Support substrate 29 is provided to integrate laminate 28 formed by laminating a plurality of capacitor elements 21, and is preferably made of a glass epoxy substrate.
[0051] FIG. 3 is another example of a cross-sectional view of the electronic component element taken along line AA shown in FIG. 1, showing a resin molded body that constitutes an electrolytic capacitor.
[0052] 3, the electronic component body 10 does not need to have a support substrate provided at the bottom. In this case, the first main surface 10a of the electronic component body 10 (resin molded body 20) is the surface of the sealing resin 22.
[0053] The above-described electronic component body 10 for an electrolytic capacitor is used in a solid electrolytic capacitor having a solid electrolyte layer, but the surface-mount electronic component manufactured by the manufacturing method of this embodiment may be an electrolytic capacitor that uses an electrolytic solution instead of a solid electrolyte, or an electrolytic capacitor that uses an electrolytic solution together with a solid electrolyte.
[0054] Furthermore, the laminate including the capacitor element preferably includes a plurality of capacitor elements, but may include a single capacitor element.
[0055] Next, a multilayer ceramic electronic component will be described as another example of a surface-mount electronic component manufactured by the manufacturing method of this embodiment.
[0056] In this case, the electronic component body preferably comprises a rectangular laminate in which at least one of dielectric ceramic layers, magnetic ceramic layers, piezoelectric ceramic layers, and semiconductor ceramic layers is stacked with internal electrode layers as internal electrodes.
[0057] Examples of the multilayer ceramic electronic components include multilayer ceramic capacitors, multilayer coils, multilayer thermistors, multilayer varistors, multilayer LC filters, and multilayer piezoelectric filters.
[0058] Here, the internal structure of an electronic component body when manufacturing a multilayer ceramic capacitor will be described.
[0059] FIG. 4 is another example of a cross-sectional view of the electronic component element taken along line AA shown in FIG. 1, showing a laminate constituting a multilayer ceramic capacitor.
[0060] In this case, as shown in FIG. 4, the electronic component body 10 is a laminate 30 in which a dielectric ceramic layer 31, an internal electrode layer 32 and an internal electrode layer 33 are laminated.
[0061] The internal electrode layers 32 and 33 are internal conductors 16, with the internal electrode layer 32 connected to a first external electrode and the internal electrode layer 33 connected to a second external electrode.
[0062] The dielectric ceramic layer 31 contains a dielectric ceramic such as barium titanate, etc. The dielectric ceramic layer can be obtained by forming a dielectric slurry containing a dielectric ceramic and an organic solvent into a sheet.
[0063] The internal electrode layers 32 and 33 can be obtained by printing an electrode paste containing a conductive component. The internal electrode layers 32 and 33 are preferably Ni electrode layers using Ni as the conductive component.
[0064] Moreover, the Ni electrode layer may be replaced with an Ag electrode layer, a Pd electrode layer, or a Cu electrode layer.
[0065] (Element placement step) Fig. 5 is an exploded perspective view schematically showing an example of a step of placing an electronic component element in the method for manufacturing a surface mount electronic component according to embodiment 1 of the present invention. Fig. 6 is a cross-sectional view schematically showing an example of a step of placing an electronic component element in the method for manufacturing a surface mount electronic component according to embodiment 1 of the present invention.
[0066] As shown in FIGS. 5 and 6, each electronic component body 10 is then arranged so that the first end face 10e and the second end face 10f face in the vertical direction.
[0067] The electronic component bodies 10 are arranged at equal intervals in directions D1 and D2 that are orthogonal to each other in a horizontal plane.
[0068] In the element placement step, it is preferable to place each electronic component element 10 on an adhesive sheet 40 containing a silicone resin. This fixes each electronic component element 10 onto the adhesive sheet 40, making it possible to print the electrode paste more stably during screen printing, which will be described later.
[0069] The adhesive sheet 40 is a substrate (tack sheet) that is made of a material in which a silicone resin, which is the main component, is mixed with an adhesive and processed into a sheet, and has adhesiveness and elasticity (cushioning properties). Therefore, each electronic component body 10 placed on the adhesive sheet 40 can withstand a load from the vertical direction.
[0070] The thickness of the adhesive sheet 40 is preferably 0.1 mm or more and 10 mm or less, more preferably 0.5 mm or more and 5 mm or less, and even more preferably 1 mm or more and 3 mm or less.
[0071] The adhesive strength of the adhesive sheet 40 is preferably 25 N or greater. If it is less than 25 N, there is a risk that the electronic component body 10 will rise toward the electrode paste (screen printing plate) during screen printing, as will be described later, and become detached from the adhesive sheet 40. The adhesive strength of the adhesive sheet 40 is measured as interfacial fracture strength by a peel test (90° peel test).
[0072] The hardness (rubber hardness) of the adhesive sheet 40 is preferably 20° or more and 40° or less. If the hardness exceeds 40°, the electronic component body 10 will be difficult to absorb into the adhesive sheet 40, and there is a risk that the screen printing plate will break at the point of contact with the squeegee during screen printing, as described below. Here, the hardness (rubber hardness) of the adhesive sheet 40 is measured using a Type A durometer (hardness tester type A) in accordance with JIS K 6253.
[0073] The in-plane thickness variation of the adhesive sheet 40 is preferably within 30 μm. If it exceeds 30 μm, the thickness of the coating of the electrode paste applied to the electronic component element 10 during screen printing, which will be described later, may vary depending on the electronic component element 10. Here, the film thickness of the adhesive sheet 40 is measured using a thickness gauge.
[0074] From the same viewpoint, it is preferable that in the element placement step, the electronic component elements 10 are placed in each of a plurality of through holes 51 of a jig 50 having through holes 51 formed in the vertical direction.
[0075] Specifically, first, the jig 50 is placed on the adhesive sheet 40, and then the electronic component body 10 is placed in each through hole 51 of the jig 50 so that the first end face 10e and the second end face 10f face up and down, respectively.
[0076] Here, each electronic component body 10 is arranged so that a predetermined gap D is provided between the second main surface 10b and the jig 50 (see FIG. 6). On the other hand, such a gap may or may not exist between the first main surface 10a of each electronic component body 10 and the jig 50.
[0077] The material of the jig 50 is not particularly limited as long as it is solvent-resistant, but is preferably a rigid body that is neither adhesive nor elastic, such as glass epoxy resin, epoxy resin, or metal.
[0078] As shown in FIG. 6, the jig 50 has an inclined surface 52a at its upper portion against which the corresponding electronic component body 10 comes into contact during screen printing, which will be described later.
[0079] Each of the inclined surfaces 52 a is provided on the upper portion of the wall surface forming the through-hole 51 , on the side of the second main surface 10 b of the electronic component body 10 .
[0080] Furthermore, an inclined surface 52 b is provided on the upper portion of the wall surface forming each through hole 51 on the side of the first main surface 10 a of the electronic component body 10 .
[0081] The inclined surfaces 52a and 52b are both flat inclined portions, and as shown in Figure 6, the opening width of each through hole 51 increases from bottom to top in the area where the pair of inclined surfaces 52a and 52b are arranged.
[0082] The size of the gap D between the second main surface 10b and the jig 50 is set so that the electronic component body 10 that falls over during screen printing, which will be described later, will fit along the slope 52a.
[0083] In this embodiment, the inclined surface 52b does not have to be provided, and for example, the upper portion of the wall surface forming each through hole 51 on the first main surface 10a side of the electronic component body 10 may be a vertical surface.
[0084] (Electrode Forming Step) Fig. 7 is a perspective view schematically showing an example of a step of forming external electrodes on the electronic component body shown in Fig. 5. Fig. 8 is a cross-sectional view schematically showing an example of a step (mesh coating) of forming external electrodes on the electronic component body shown in Fig. 6.
[0085] Next, a mesh screen printer is used to print electrode paste onto the plurality of electronic component bodies 10 .
[0086] First, as shown in Figures 7 and 8, a mesh screen 60 is placed on the electronic component element 10 as a screen printing plate, and electrode paste 61 is applied onto the mesh screen 60. A gap (clearance) of a predetermined size is provided between the electronic component element 10 and the mesh screen 60. Then, a squeegee 62 is moved over the mesh screen 60 in the squeegeeing direction (the direction in which the squeegee 62 moves) to perform squeegeeing. The height of the squeegee 62 is adjusted so that at this stage the mesh screen 60 and the electrode paste 61 do not come into contact with the electronic component element 10, and the electrode paste 61 accumulates on the mesh screen 60. Then, a portion of the electrode paste 61 accumulated on the mesh screen 60 protrudes onto the underside of the mesh screen 60 (the side opposite to the squeegeeed surface).
[0087] Fig. 9 is a cross-sectional view schematically showing an example of a step (screen printing) of forming external electrodes on the electronic component body shown in Fig. 8. Fig. 10 is a cross-sectional view schematically showing an example of a step (after screen printing) of forming external electrodes on the electronic component body shown in Fig. 8.
[0088] 9, the electronic component body 10 is turned over toward the second main surface 10b, and the electrode paste 61 is screen-printed onto the first end face 10e and the first main surface 10a, so that the electrode paste 61 is applied onto the first end face 10e and the first main surface 10a. The electrode paste 61 is then thermally cured to form external electrodes on the first end face 10e and the first main surface 10a.
[0089] More specifically, first, electrode paste 61 is applied onto mesh screen 60, and then squeegee 62 is moved over mesh screen 60 to perform squeegeeing. At this time, the height of squeegee 62 is adjusted so that the tip of squeegee 62 is slightly lower than first end face 10e of electronic component element 10. Then, just before squeegee 62 arrives, mesh screen 60 is pressed downward by squeegee 62 and comes into contact with first end face 10e of electronic component element 10, thereby applying electrode paste 61 to the entire first end face 10e. Then, when squeegee 62 arrives, the upper part of electronic component element 10 is pressed in the squeegeeing direction. When the shear stress generated at the interface between the electronic component body 10 and the adhesive sheet 40 exceeds a threshold value, a gap D exists between the second main surface 10b and the jig 50, and so the electronic component body 10 begins to rotate about the ridge portion 11bf where the second main surface 10b and the second end face 10f intersect, and the electronic component body 10 falls until it abuts against the jig 50 (particularly the slope 52a). At this time, the mesh screen 60 remains in contact with the electronic component body 10 while the electronic component body 10 is falling, and the electrode paste 61 is also applied to the first main surface 10a of the electronic component body 10 (particularly a portion of the first end face 10e side).
[0090] 10 , the electrode paste 61 is applied not only to the first end face 10e of the electronic component body 10 but also to the first main surface 10a of the electronic component body 10. Furthermore, the electrode paste 61 has a larger film thickness on the ridge line 11ae where the first end face 10e and the first main surface 10a intersect, which ensures a sufficient film thickness (dimension G) of the external electrode at the edge portion (particularly the ridge line 11ae) of the electronic component body 10. Therefore, according to this embodiment, external electrodes with excellent coverage at the edge portion of the electronic component body 10 can be easily formed.
[0091] Furthermore, costs can be reduced because there is no need to apply electrode paste 61 to all four surfaces, i.e., the first main surface 10a, the second main surface 10b, the first side surface 10c, and the second side surface 10d. Also, because no external electrodes are formed on the second main surface 10b, i.e., the top surface, short circuits are less likely to occur even if the finished surface-mounted electronic component comes into contact with other components or the lid.
[0092] During the above-mentioned screen printing, the electrode paste 61 may also be applied to the first side surface 10c and the second side surface 10d of the electronic component body 10 (particularly to the areas near the corners where the first side surface 10c and the second side surface 10d intersect with the first end surface 10e and the first main surface 10a, respectively).
[0093] Unlike the above method, it is also possible to perform screen printing while the electronic component body is tilted from the beginning. In this case, however, the electrode paste will not be applied to the entire first end face of the electronic component body, but only to the portion of the first end face facing the first main surface.
[0094] The amount of electrode paste 61 applied to the first main surface 10a of the electronic component body 10 (how far on the first main surface 10a the electrode paste 61 is applied from the ridge line 11ae) can be controlled by the tilt angle of the electronic component body 10 during screen printing. A larger tilt angle of the electronic component body 10 increases the amount of electrode paste 61 applied to the first main surface 10a. As a result, the dimension (dimension E) of the external electrode on the first main surface 10a increases.
[0095] More specifically, during screen printing, the maximum inclination angle θ1 of the electronic component body 10 relative to the vertical direction is preferably 10° or more and 45° or less.
[0096] As described above, during screen printing, it is preferable to tilt the electronic component body 10 until it abuts against the jig 50 (particularly the slope 52 a), which stabilizes the maximum tilt angle of the electronic component body 10 and allows for more stable printing of the electrode paste.
[0097] The angle φ1 of the inclined surface 52a relative to the vertical direction is preferably 20° to 45°, which makes it easy to set the maximum inclination angle θ1 of the electronic component body 10 within the above range.
[0098] The screen printing plate to be used is not particularly limited, but from the viewpoint of cost, it is preferable to use the mesh screen 60 for screen printing, as described above.
[0099] The mesh screen 60 can be made of, for example, stainless steel such as SUS or wires made of high-tensile resin such as polyester woven into a mesh shape.
[0100] The electrode paste 61 to be used is not particularly limited, and any paste that has been used for forming external electrodes by conventional screen printing can be used, but metal paste and conductive polymer paste are particularly preferred.
[0101] The metal paste preferably contains a conductive component (metallic fine particles) such as Ag, Cu, Ni, etc., and an insulating resin component as a binder component.
[0102] The conductive polymer paste preferably contains a conductive component (conductive polymer) such as a polythiophene resin, a polyacetylene resin, a polyaniline resin, or a polypyrrole resin, and a resin component as a binder component. The conductive polymer preferably contains a dopant such as polystyrene sulfonic acid to improve conductivity.
[0103] After forming external electrodes on the first end face 10e and the first main surface 10a, similar screen printing can be performed on the second end face 10f side of the electronic component body 10, thereby screen-printing electrode paste 61 on the second end face 10f and the first main surface 10a, and forming external electrodes on the second end face 10f and the first main surface 10a as well.
[0104] An outer plating layer may be formed on the electrode layer after the electrode layer is formed using the electrode paste 61. The outer plating layer may include a Ni plating layer and a Sn plating layer on the Ni plating layer.
[0105] (Surface Mount Electronic Component) Fig. 11 is a perspective view schematically showing an example of a surface mount electronic component manufactured by the manufacturing method for a surface mount electronic component according to embodiment 1 of the present invention. Fig. 12 is a first side view of the surface mount electronic component shown in Fig. 11. Fig. 13 is a second side view of the surface mount electronic component shown in Fig. 11.
[0106] As shown in Figures 11, 12, and 13, a surface-mount electronic component 100 manufactured by the manufacturing method of this embodiment has an electronic component body 10, a first external electrode 110, and a second external electrode 120.
[0107] The first external electrode 110 is formed integrally with the first end face 10e and the first main surface 10a of the electronic component body 10. Therefore, the first external electrode 110 has an L-shape in a cross section parallel to the first side surface 10c.
[0108] The first external electrode 110 may also be formed integrally with the first side surface 10 c and the second side surface 10 d. More specifically, the first external electrode 110 may also be formed on the first side surface 10 c near a corner 12 ace where the first end surface 10 e, the first main surface 10 a, and the first side surface 10 c intersect, as shown in Fig. 12 , or may also be formed on the second side surface 10 d near a corner 12 ade where the first end surface 10 e, the first main surface 10 a, and the second side surface 10 d intersect, as shown in Fig. 13 .
[0109] In addition, the first external electrode 110 may also be formed on the ridge portions (particularly rounded ridge portions) where the first end face 10e intersects with the second main face 10b, the first side face 10c, or the second side face 10d.
[0110] The second external electrode 120 is formed integrally with the second end face 10f and the first main surface 10a of the electronic component body 10. Therefore, the second external electrode 120 has an L-shape in cross section parallel to the first side surface 10c.
[0111] The second external electrode 120 may also be formed integrally with the first side surface 10 c and the second side surface 10 d. More specifically, the second external electrode 120 may also be formed on the first side surface 10 c near a corner 12 acf where the second end surface 10 f, the first main surface 10 a, and the first side surface 10 c intersect, as shown in Fig. 12 , or may also be formed on the second side surface 10 d near a corner 12 adf where the second end surface 10 f, the first main surface 10 a, and the second side surface 10 d intersect, as shown in Fig. 13 .
[0112] The second external electrode 120 may also be formed on the ridge portions (particularly rounded ridge portions) where the second end face 10f intersects with the second main face 10b, the first side face 10c, or the second side face 10d.
[0113] Because the first external electrode 110 is formed by the above-described screen printing, it is possible to ensure a sufficient film thickness G1 (G dimension) at the edge portions of the electronic component body 10, particularly at the ridge portions 11ae where the first end face 10e and the first main surface 10a intersect, as shown in Figures 12 and 13. Similarly, it is possible to ensure a sufficient film thickness G2 (G dimension) for the second external electrode 120 at the edge portions of the electronic component body 10, particularly at the ridge portions 11af where the second end face 10f and the first main surface 10a intersect, as shown in Figures 12 and 13.
[0114] The dimensions E1 and E2 (dimension E) of the first external electrode 110 and the second external electrode 120 on the first main surface 10a are controlled by the inclination angle of the electronic component body 10 during the screen printing.
[0115] Although the type of surface mount electronic component 100 manufactured by the manufacturing method of this embodiment is not particularly limited, an electrolytic capacitor is suitable because a large space can be secured on the second main surface 10b, where the first external electrode 110 and the second external electrode 120 are not formed, for printing a mark indicating the polarity of the electrolytic capacitor.
[0116] [Embodiment 2] Next, a method for manufacturing a surface mount electronic component according to embodiment 2 of the present invention will be described. This embodiment is substantially the same as embodiment 1, except that screen printing is performed twice per end surface in two directions while the electronic component body is tilted.
[0117] FIG. 14 is a cross-sectional view schematically showing an example of a step of arranging an electronic component element in the method for manufacturing a surface mount electronic component according to the second embodiment of the present invention.
[0118] 14, each electronic component body 10 is arranged so that the first end face 10e and the second end face 10f face up or down, as in the first embodiment. However, each electronic component body 10 is arranged so that a gap D is provided not only between the second main surface 10b and the jig 50, but also between the first main surface 10a and the jig 50. That is, in this embodiment, the opening width of each through hole 51 is wider by the amount of the gap D on the first main surface 10a side than in the first embodiment.
[0119] Fig. 15 is a cross-sectional view schematically showing an example of a step (first screen printing) of forming external electrodes on the electronic component body shown in Fig. 14. Fig. 16 is a cross-sectional view schematically showing an example of a step (after the first screen printing) of forming external electrodes on the electronic component body shown in Fig. 14.
[0120] Next, as in embodiment 1, electrode paste 61 is collected on the mesh screen 60 so that the mesh screen 60 and electrode paste 61 do not come into contact with the electronic component body 10 (see Figure 8), and then, as shown in Figures 15 and 16, the electronic component body 10 is tilted toward the second main surface 10b, and the electrode paste 61 is screen-printed on the first end face 10e and the first main surface 10a.
[0121] FIG. 17 is a cross-sectional view schematically showing an example of a step (second mesh coating) of forming external electrodes on the electronic component body shown in FIG.
[0122] 17, each electronic component body 10 is rearranged (raised up) so that the first end face 10e and the second end face 10f face up and down, respectively. Then, the height of the squeegee 62 is adjusted (raised) so that the mesh screen 60 and the electrode paste 61 do not come into contact with the electronic component body 10, and the electrode paste 61 accumulates on the mesh screen 60.
[0123] Fig. 18 is a perspective view schematically showing an example of a step (second screen printing) of forming external electrodes on the electronic component body shown in Fig. 17. Fig. 19 is a perspective view schematically showing an example of a step (after the second screen printing) of forming external electrodes on the electronic component body shown in Fig. 17.
[0124] 18 and 19 , as in the first embodiment, the electronic component body 10 is turned over toward the first main surface 10a (the opposite side from the first screen printing), and the electrode paste 61 is screen-printed on the first end surface 10e and the second main surface 10b, thereby applying the electrode paste 61 to the first end surface 10e and the second main surface 10b. This second screen printing is performed without drying or thermally curing the electrode paste 61 applied in the first screen printing. Then, the electrode paste 61 is thermally cured to form external electrodes on the first end surface 10e, the first main surface 10a, and the second main surface 10b.
[0125] During the second screen printing, the maximum inclination angle θ2 of the electronic component body 10 with respect to the vertical direction is preferably 10° or more and 45° or less.
[0126] The maximum inclination angle θ2 of the electronic component body 10 may be substantially the same as the maximum inclination angle θ1 of the electronic component body 10 during the first screen printing.
[0127] The angle φ2 of the inclined surface 52b with respect to the vertical direction can be set as appropriate, but is preferably 20° or more and 45° or less.
[0128] The angle φ2 formed by the slope 52b may be substantially the same as the angle φ1 formed by the opposite slope 52a.
[0129] During the second screen printing, the electrode paste 61 may also be applied to the first side surface 10c and the second side surface 10d of the electronic component body 10 (particularly to the areas near the corners where the first side surface 10c and the second side surface 10d intersect with the first end surface 10e and the second main surface 10b, respectively).
[0130] (Surface Mount Electronic Component) Fig. 20 is a perspective view schematically showing an example of a surface mount electronic component manufactured by the manufacturing method for a surface mount electronic component according to embodiment 2 of the present invention. Fig. 21 is a first side view of the surface mount electronic component shown in Fig. 20. Fig. 22 is a second side view of the surface mount electronic component shown in Fig. 20.
[0131] As shown in Figures 20, 21, and 22, a surface-mount electronic component 200 manufactured by the manufacturing method of this embodiment has the same electronic component body 10 as in embodiment 1, a first external electrode 210, and a second external electrode 220.
[0132] The first external electrode 210 is formed integrally with the first end face 10e, the first main surface 10a, and the second main surface 10b of the electronic component body 10. Therefore, the first external electrode 210 has a U-shape (C-shape) in a cross section parallel to the first side surface 10c.
[0133] The first external electrode 210 may also be formed integrally with the first side surface 10 c and the second side surface 10 d. More specifically, as shown in Fig. 21 , the first external electrode 210 may also be formed on the first side surface 10 c near a corner 12 ace where the first end surface 10 e, the first main surface 10 a, and the first side surface 10 c intersect, and near a corner 12 bce where the first end surface 10 e, the second main surface 10 b, and the first side surface 10 c intersect, or as shown in Fig. 22 , the first external electrode 210 may also be formed on the second side surface 10 d near a corner 12 ade where the first end surface 10 e, the first main surface 10 a, and the second side surface 10 d intersect, and near a corner 12 bde where the first end surface 10 e, the second main surface 10 b, and the second side surface 10 d intersect.
[0134] The first external electrode 210 may also be formed on the ridges (particularly rounded ridges) where the first end face 10e intersects with the first side face 10c or the second side face 10d.
[0135] The second external electrode 220 is formed integrally with the second end face 10 f, the first main surface 10 a, and the second main surface 10 b of the electronic component body 10. Therefore, the second external electrode 220 has a U-shape (C-shape) in a cross section parallel to the first side surface 10 c.
[0136] The second external electrode 220 may be formed integrally with the first side surface 10 c and the second side surface 10 d. More specifically, as shown in Fig. 21 , the second external electrode 220 may be formed on the first side surface 10 c near a corner 12 acf where the second end surface 10 f, the first main surface 10 a, and the first side surface 10 c intersect, and near a corner 12 bcf where the second end surface 10 f, the second main surface 10 b, and the first side surface 10 c intersect, or as shown in Fig. 22 , the second external electrode 220 may be formed on the second side surface 10 d near a corner 12 adf where the second end surface 10 f, the first main surface 10 a, and the second side surface 10 d intersect, and near a corner 12 bdf where the second end surface 10 f, the second main surface 10 b, and the second side surface 10 d intersect.
[0137] The second external electrode 220 may also be formed on the ridges (particularly rounded ridges) where the second end face 10f intersects with the first side face 10c or the second side face 10d.
[0138] Because the first external electrode 210 is formed by the above-described screen printing, it is possible to ensure a sufficient film thickness G1 (G dimension) at the edge portions of the electronic component body 10, particularly at the ridge portion 11ae where the first end face 10e and the first main surface 10a intersect, and a sufficient film thickness G3 (G dimension) at the ridge portion 11be where the first end face 10e and the second main surface 10b intersect, as shown in Figures 21 and 22. Similarly, it is possible to ensure a sufficient film thickness G2 (G dimension) at the edge portions of the electronic component body 10, particularly at the ridge portion 11af where the second end face 10f and the first main surface 10a intersect, and a sufficient film thickness G4 (G dimension) at the ridge portion 11bf where the second end face 10f and the second main surface 10b intersect, as shown in Figures 21 and 22.
[0139] The respective dimensions E1 and E2 (E dimension) of the first external electrode 210 and the second external electrode 220 on the first main surface 10a, and the respective dimensions E3 and E4 (E dimension) of the first external electrode 210 and the second external electrode 220 on the second main surface 10b are each controlled by the inclination angle of the electronic component body 10 during the above-mentioned screen printing.
[0140] Although the type of surface mount electronic component 200 manufactured by the manufacturing method of this embodiment is not particularly limited, a multilayer ceramic electronic component, particularly a multilayer ceramic capacitor, is suitable because multilayer ceramic capacitors can be miniaturized, and in such cases, it is difficult to distinguish between the first main surface 10 a and the second main surface 10 b.
[0141] The present specification discloses the following:
[0142] <1> A method for manufacturing a surface mount electronic component, comprising: an element preparation step of preparing a rectangular parallelepiped electronic component element having an internal conductor, the electronic component element having first and second main surfaces opposing each other in a height direction, first and second side surfaces opposing each other in a width direction, and first and second end surfaces opposing each other in a length direction; an element placement step of placing the electronic component element so that the first end surfaces and the second end surfaces face up and down, respectively; and an electrode formation step of screen-printing an electrode paste on the first end surfaces and the first main surfaces while tilting the electronic component element towards the second main surface, to form external electrodes on the first end surfaces and the first main surfaces.
[0143] <2> The method for manufacturing a surface mount electronic component according to <1>, wherein in the element placement step, the electronic component element is placed on an adhesive sheet containing a silicone resin.
[0144] <3> The method for manufacturing a surface mount electronic component according to <1> or <2>, wherein the maximum inclination angle of the electronic component body relative to the vertical direction during the screen printing is 10° or more and 45° or less.
[0145] <4> The method for manufacturing a surface mount electronic component according to any one of <1> to <3>, wherein a mesh screen is used for the screen printing.
[0146] <5> The method for manufacturing a surface mount electronic component according to any one of <1> to <4>, wherein in the element placement step, the electronic component element is placed in a through hole of a jig having a through hole formed in the vertical direction, and during the screen printing, the electronic component element is tilted down until it abuts against the jig.
[0147] <6> The method for manufacturing a surface mount electronic component according to <5>, wherein the jig has an inclined surface on an upper portion thereof against which the electronic component body abuts during the screen printing, and the inclined surface forms an angle of 20° or more and 45° or less with respect to the vertical direction.
[0148] <7> The method for manufacturing a surface mount electronic component according to any one of <1> to <6>, wherein the electrode paste includes at least one of a metal paste and a conductive polymer paste.
[0149] <8> The method for manufacturing a surface mount electronic component according to any one of <1> to <7>, wherein in the electrode forming step, the electrode paste is screen-printed on the first end surface and the first main surface, and then the electronic component body is tilted toward the first main surface while screen-printing the electrode paste on the first end surface and the second main surface, thereby forming the external electrodes on the first end surface, the first main surface, and the second main surface.
[0150] <9> The method for manufacturing a surface-mounted electronic component according to any one of <1> to <8>, wherein the surface-mounted electronic component is an electrolytic capacitor.
[0151] <10> The method for manufacturing a surface-mounted electronic component according to any one of <1> to <8>, wherein the surface-mounted electronic component is a multilayer ceramic electronic component.
[0152] REFERENCE SIGNS LIST 10 Electronic component body 10a First main surface 10b Second main surface 10c First side surface 10d Second side surface 10e First end surface 10f Second end surface 11ae, 11af, 11be, 11bf Ridge line portion 12ace, 12acf, 12ade, 12adf, 12bce, 12bcf, 12bde, 12bdf Corner portion 16 Internal conductor 20 Resin molded body 21 Capacitor element 22 Sealing resin 23 Anode 23a Valve action metal foil 25 Dielectric layer 27 Cathode 27a Solid electrolyte layer 27b Conductive layer 27c Cathode lead layer 28 Laminate 29 Support substrate 30 Laminate 31 Dielectric ceramic layer 32, 33 Internal electrode layer 40 Adhesive sheet 50 Jig 51 Through-hole 52a, 52b Sloped surface 60 Mesh screen 61 Electrode paste 62 Squeegee 100, 200 Surface-mounted electronic component 110, 210 First external electrode 120, 220 Second external electrode
Claims
1. an element preparation step of preparing a rectangular parallelepiped electronic component element having an internal conductor, a first main surface and a second main surface opposing each other in a height direction, a first side surface and a second side surface opposing each other in a width direction, and a first end surface and a second end surface opposing each other in a length direction; an element placement step of placing the electronic component element so that the first end surface and the second end surface each face in a vertical direction; and an electrode formation process of screen-printing an electrode paste on the first end surface and the first main surface while tilting the electronic component body toward the second main surface, thereby forming external electrodes on the first end surface and the first main surface.
2. The method for producing a surface mount electronic component according to claim 1 , wherein in the element placement step, the electronic component element is placed on an adhesive sheet containing a silicone resin.
3. 3. The method for manufacturing a surface mount electronic component according to claim 1, wherein a maximum inclination angle of the electronic component body with respect to the vertical direction during the screen printing is not less than 10[deg.] and not more than 45[deg.].
4. The method for manufacturing a surface mount electronic component according to claim 1 or 2, wherein a mesh screen is used for the screen printing.
5. In the element placement step, the electronic component element is placed in a through hole of a jig having a through hole in a vertical direction; 3. The method for manufacturing a surface mount electronic component according to claim 1, wherein the electronic component body is tilted down until it abuts against the jig during the screen printing.
6. the jig has an inclined surface at an upper portion thereof against which the electronic component body comes into contact during the screen printing, 6. The method for manufacturing a surface mount electronic component according to claim 5, wherein an angle of the inclined surface with respect to the vertical direction is not less than 20 degrees and not more than 45 degrees.
7. The method for producing a surface mount electronic component according to claim 1 , wherein the electrode paste includes at least one of a metal paste and a conductive polymer paste.
8. 3. The method for manufacturing a surface mount electronic component according to claim 1, wherein in the electrode formation process, the electrode paste is screen-printed on the first end face and the first main surface, and then the electronic component body is tilted toward the first main surface while screen-printing the electrode paste on the first end face and the second main surface, thereby forming the external electrodes on the first end face, the first main surface, and the second main surface.
9. The method for manufacturing a surface mount type electronic component according to claim 1 , wherein the surface mount type electronic component is an electrolytic capacitor.
10. 3. The method for manufacturing a surface mount type electronic component according to claim 1, wherein the surface mount type electronic component is a multilayer ceramic electronic component.